Sparks v Hobson; Gray v Hobson

The mechanism of the respondent's injury

1. A neurologist, Dr Guy Sawle, identified the cause of the respondent's paraplegia as "a spinal cord stroke" caused by damage to the spinal cord, which, in turn, was caused by oxygen deficiency that resulted in obstruction of circulation. This view was also expressed by others of the experts. A contributing factor to the oxygen deficiency was the first operation, which had had the effect of reducing the number of arteries supplying blood to the spinal cord. (There is no suggestion of negligence in the performance of the first operation. As mentioned above, reduction of the number of arteries was a necessary consequence of the first part of the surgery.) A second factor was "the period of circulatory collapse" during the second operation. Dr Sawle considered that the spinal cord stroke occurred "shortly before" the decision to terminate the operation, at about 21:30, and not during the earlier episodes of low blood pressure and hypoxia. This was said by the primary judge to be uncontroversial.

The case at trial

1. The respondent's claim in negligence was governed by the Civil Liability Act 2002 (NSW) ("the CLA"). The case in contract was particularised in the same way as the case in negligence, and depended upon the same allegations of breach of duty.
2. Although, as set out in the judgment of Macfarlan JA, the primary judge found negligence against Dr Sparks in only one respect (failure to direct the cessation of the surgery at a point earlier than he did), to approach the appeal on that basis only is to mask the way the case was conducted.
3. As finally pleaded against all defendants, multiple particulars of negligence were identified. Notwithstanding the multiplicity of particulars, the case pleaded depended essentially on two allegations: (i) that the commencement of (or the failure to delay) the surgery in the absence of spinal cord monitoring, which was intended to be undertaken by Dr Lagopoulos, or to ensure "complete and effective" spinal cord monitoring was negligent; and (ii) that failure to halt or advise the cessation of the surgery following the adverse signs at various times during the procedure (specified as 18:50, 19:10, 20:35 and 21:20) was negligent. As against Dr Gray, it was also pleaded that the surgery ought not to have been commenced at the time it was, and that there was no necessity for the operation to have been performed as an emergency procedure. As against Dr Sparks, additional particulars asserted: (i) that he had negligently failed to advise Dr Gray that a probable cause of failure of the spinal cord monitoring was the use of the chosen anaesthetics and muscle relaxants and that an alternative which did not affect the monitoring should have been used, and (ii) that he had negligently failed to inform Dr Gray that the likely cause of the respondent's ventilation problems was that he was in a prone position and that this could not be solved in any way other than returning him to a supine position.
4. Both Dr Gray and Dr Sparks denied all allegations of negligence. Dr Gray denied any causal connection between any breach of duty proved against him (relying on s 5D of the CLA), and asserted that he had acted in a manner that was widely accepted in Australia by peer professional opinion as competent professional practice (CLA, s 5 O). Dr Sparks also relied on s 5 O of the CLA, and on s 5 I, which provides that a person is not liable in negligence for harm resulting from the materialisation of an inherent risk.
5. The case presented at trial fluctuated from time to time. At the commencement of the hearing, senior counsel opened with something of a flourish. He said: "Now, the second procedure was brought forward for reasons which have been expressed as dramatically as, 'if we didn't do it, he was going to die', but at its most benign, he was having respiratory difficulties, but respiratory difficulties would be cured, it was hoped, by the second stage; therefore, it was appropriate to bring the surgery forward. At the end of the day, your Honour will conclude that the melodrama was confected, that is to say, it was ex post facto justification for what was done. And the reality was that it was simply convenient."
6. In response to a question from the primary judge, he explained "convenient" as: "… it enabled the surgeon to get all this team together when they were not all available later." He described the decision as "pragmatism". He then described as "a grim irony" that, while the surgery was timed to enable Dr Lagopoulos to be present, he was, in fact, late arriving.
7. By the time senior counsel came to cross-examine Dr Sparks (on the first day of hearing), the position had changed somewhat. Senior counsel commenced his cross-examination by saying: "… it's not part of the plaintiff's case that the commencement of this surgery was not reasonable or not indicated. So, we're not saying the surgery should never have started."
8. During the course of cross-examination he said: "… I accept as my first premise that it was reasonable to commence the surgery. My second premise was though that when it became obvious, as it did, that the surgery was proving to be much more fraught and much more dangerous than it seems you, at least, had assumed, it should have been stopped then. That's what I'm suggesting to you."
9. At the commencement of proceedings the following day, the position changed yet again. Echoing his affidavit evidence, Dr Sparks had given evidence in cross-examination to the effect that if the surgery were elective, he would not have "accepted to take [the respondent] to theatre". Senior counsel said: "… we will submit that the surgery should never have started." He said that the respondent's case was put in the alternative - that the surgery should not have been commenced, and that, if it had, it should have been terminated.
10. Written submissions were produced at the conclusion of the proceedings. In the opening paragraph of the respondent's written submissions, the attack on the decision to bring the surgery forward was again abandoned; it was expressly accepted that the decision to do so was reasonable. The principal submission made in relation to Dr Sparks was: "169 Dr Sparks was negligent in not advising that surgery should have been abandoned at no later than 20:37. He was alive to the patient's metabolic deterioration which would have caused a reasonably competent anaesthetist to call a stop to the surgery."

Medical evidence

1. Apart from Dr Sparks, reports or affidavits were provided by six anaesthetists, five of whom gave oral evidence.
2. As indicated above, until the tenth day of the trial, four defendants were involved. The parties adopted the sensible course of providing the primary judge at the outset with agreed bundles of documents, which included affidavits and expert reports prepared on behalf of the respondent and the defendants (including those defendants who were subsequently released from the proceedings, RNSH and Dr Lagopoulos). That material remained part of the proceedings even after the departure of those two defendants.
3. It is relevant to observe that, as is obvious, the interests of the defendants were divergent, and it was inevitable that, at times, it would suit one defendant to defend his position by shifting the responsibility for certain decisions to another of the defendants. This can most plainly be seen where Dr Gray asserted (correctly in my opinion) that, since the complications that eventually called for cessation of the surgery were related to anaesthetic issues, the principal liability for that decision lay with Dr Sparks. The practical effect of this aspect of the proceedings was that some of the evidence given in Dr Gray's defence bore upon the case against Dr Sparks.
4. The parties also adopted the course of having the medical practitioners retained for the purpose of providing expert opinion meet in conclave and furnish joint reports prior to the hearing. Thus, an anaesthetist who had provided opinion evidence for the respondent (Dr Jon Westbrook) met with an anaesthetist (Dr Paul Forrest) retained by Dr Sparks' solicitors for the purpose of providing opinion evidence. A similar course was taken with respect to orthopaedic experts retained, respectively, by solicitors for the respondent and Dr Gray. The experts then gave their oral evidence concurrently (Dr Westbrook from the United Kingdom).
5. Dr Westbrook is a consultant anaesthetist at the John Radcliffe Hospital in Oxford, UK. He provided a number of reports to the respondent's solicitors, the first dated 10 January 2012.
6. In his reports Dr Westbrook addressed a number of questions. At times, he appeared to question the techniques and instrumentation selected by Dr Sparks. For example, initially Dr Westbrook appeared to query the appropriateness of Dr Sparks' decision to use a double lumen tube, although he later retreated from this position.
7. Relevantly to the present question, whether it was negligent of Dr Sparks not to abandon the surgery earlier, Dr Westbrook said: "Having positioned the patient prone and shown that the endotracheal tube position was not optimal and that the ventilation was difficult and the carbon dioxide level very high a decision could have been taken to abandon surgery at that point … As the decision had already been made to bring forward Mr Hobson['s] surgery because of his deteriorating condition the team may have decided to proceed on that basis." (italics added)
8. Dr Westbrook provided a further report and supplementary report, both dated 21 October 2012. In the earlier of these reports, he said: "The decision to perform Mr Hobson's second operation as an emergency on the evening of 17th November 2009 appears to be critical to this case and the adverse outcome. It meant that the anaesthetists had to persist with an anaesthetic technique that was not achieving optimal gas exchange and ultimately resulted in a significant period of hypoxaemia and hypotension. This appears to have been the cause of Mr Hobson's spinal injury. In addition the operation and the work up to it was commenced before spinal cord monitoring was available. Although it arrived shortly after the start it was not possible to obtain baseline measurements. The monitoring was reported as abnormal throughout the case but this could have been due in part to the anaesthetic difficulties and the use of vecuronium making interpretation very difficult. It is likely that had spinal cord monitoring been properly established in a timely manner that there would have been advanced warning to the clinicians that spinal cord perfusion was threatened particularly during the transient, earlier episodes of hypoxaemia … In the absence of any threat to Mr Hobson's life or spinal cord whilst on the intensive care unit on 17th November 2009 the decision to perform emergency surgery needs to be justified."
9. In the supplementary report of the same date, Dr Westbrook said: "On the balance of probabilities had the surgery been abandoned before the start when the anaesthetic team were already in difficulty Mr Hobson would not have had the problems he had nor suffered his spinal cord injury. There was not sufficient surgical or medical indication to undertake the surgery that night with anything other than optimal ventilation and haemodynamics."
10. In his last report, dated 24 August 2016, Dr Westbrook again addressed the decision to bring the surgery forward, and expressed the view that the assessment of the surgery as "lifesaving" was "erroneous", and that that, in turn, explained the decision to persist despite the adverse signs. He again questioned the decision to expedite the surgery and concluded: "It was the correct decision to abandon the surgery following the episode of severe collapse. There were opportunities earlier in the procedure when the anaesthetic team were struggling to achieve adequate ventilation and oxygenation and effective spinal cord monitoring was not in place for the team to discuss discontinuing the surgery … As previously stated this was a very difficult case given the highly complex surgery in a patient with significant comorbidities and very distorted anatomy causing compression of intra-thoracic structures including the heart and the left main bronchus. Dr Sparks would appear to have persisted with a suboptimal anaesthetic when consideration should have been given to abandoning the procedure. Subsequent statements by Dr Sparks and other members of the medical team suggest that they had assessed the operation to be lifesaving. It is not clear from the notes or Mr Hobson's subsequent progress that this was a correct assessment." (italics added)
11. In a series of reports, Dr Westbrook gradually modified his position with respect to the validity (or otherwise) of the decision to perform the surgery on the evening of 17 November. By the time he gave oral evidence, he considered that, because of the compression of the respondent's bronchus, it was reasonable to commence the surgery when it was commenced.
12. Dr Barratt, the anaesthetist who had assisted Dr Sparks in the bronchoscopy performed on the afternoon of 17 November, and had been consulted by Dr Sparks during the course of the surgery, filed an affidavit on behalf of RNSH. His affidavit was factual, essentially giving an account of the earlier bronchoscopy, and of his conversation with Dr Sparks during the surgery. He did not then express any opinion relevant to the issues raised in the proceedings. He gave the following oral evidence: "Q. Dr Sparks told you that the various metabolic indicators were critical. A. Yes, yes. Q. Despite, apparently, adequate blood pressure and blood oxygen levels. That was one of his dilemmas, wasn't it? A. Yes, yep. Q. Then in those circumstances, it really wasn't appropriate, was it, to look at the blood pressure and blood oxygen levels alone when making a decision whether to persist or abandon surgery? A. I agree with that statement."
13. Dr Wang also provided an affidavit on behalf of RNSH. Dr Wang had assisted the primary anaesthetist (not Dr Sparks) during the first stage surgery. He also assisted Dr Sparks during the second stage procedure. In his affidavit, he gave a factual account of what had occurred during the surgery. He, too, withheld expressing any opinion about the issues in the case.
14. The transcript records the following exchange in cross-examination: "Q. When were there indications to your recollection of when it looked as if he was going to crash? A. Before 9.30. Is it 9.30 when he was about to crash? Blood pressure came down and the saturation came and bradycardia-- Q. What about earlier when Dr Sparks was on the phone to Dr Barrett? There were signs then, weren't there, that he could crash? A. Yes. Q. Did you think at that time, 'We really should be stopping this'? A. I didn't think so at the time. Q. But you were conscious, weren't you, at that time that this is what could happen? HIS HONOUR: Sorry. What could happen? [SENIOR COUNSEL]: That he would crash later. WITNESS: To explain-- [SENIOR COUNSEL] Q. No. I don't want to stop you from explaining but I would like to get an answer to the question which was: at about the time of the Dr Barrett conversation, there were indications, weren't there, that he might well be heading towards a crash? A. There were indications, yes. Q. That was a time, wasn't it, at least when the surgery should have stopped? A. Not necessarily. Q. Not necessarily? Why do you say that? A. Because in my mind the way I perceived the operation, if we don't do the operation he will die. Up until that point, hemodynamically he was still stable. We are drifting - you know, it's difficult but we were managing. He hasn't crashed. If we stopped then, he could die. Q. From what? A. From the reason why we brought him to the operating theatre. Q. All of this proceeds upon an assumption that you had an understanding from somebody else that if the surgery didn't take place then, he would die. Is that correct? A. That's my impression at the time, yes. Q. Your impression? A. Yes, my understanding at the time. Q. So then when he did crash, you say that the anaesthetic team which obviously included yourself-- A. Yes. Q. --and the surgical team together promptly and ultimately made the decision to abandon the operation. Correct? A. Yes."
15. Dr Mike Lambros is a consultant anaesthetist who provided a report to the solicitors acting for Dr Gray. Dr Lambros did not express any opinion about the appropriateness of continuing the surgery to 21:28.
16. Dr Bojidar Manasiev is a specialist anaesthetist who also provided a report to Dr Gray's solicitors, specifically responding to a series of questions put to him by the solicitors representing Dr Gray. In a question numbered 2, Dr Manasiev was asked whether Dr Gray should have advised the halting of the surgery (at any of the times nominated in the particulars outlined above), and if not, to explain his reasons. He gave a lengthy written answer, which included: "… the decision was balanced against the apparent necessity of the operation as a potential lifesaving technique. As such, it was not warranted by Dr Sparks or Dr Gray to halt the surgery at this time and would be considered widely accepted in Australia by peer professional opinion as competent medical practice to continue the surgery." He was also asked whether Dr Gray was negligent in continuing the operation "in the face of the anaesthetic events [described] in the Further Amended Statement of Claim" (those events being the instances of hypoxia and hypotension at 18:50, 19:10 and 21:20). Dr Manasiev replied: "In my opinion, Dr Gray was not negligent in continuing the operation in the circumstances pleaded. As outlined in my answer to 2. above, the management of the ventilatory and cardiovascular parameters is the primary responsibility of the anaesthetist. Dr Sparks' management of the plaintiff in regards to directing Dr Gray to continue the surgery at 18:50, 19:10 and 20:35 and halt the surgery at 21:20 would be considered widely accepted in Australia by peer professional opinion as competent medical practice, with reasoning for each specific time as outlined in question 1 above. As such it would be considered competent medical practice by Dr Gray to heed Dr Sparks' direction and proceed with the surgery at times 18:50, 19:10 and 20:35 and halt the surgery at 21:20."
17. Dr Paul Forrest is the head of Cardiothoracic Anaesthesia and Perfusion at the Royal Prince Alfred Hospital Sydney and a Clinical Associate Professor at Sydney University. He provided a report to Dr Sparks' solicitors dated 26 October 2013. In answer to a specific question, he said that it was "appropriate and reasonable" for Dr Sparks to direct Dr Gray to cease performing surgery at the time he did. In answer to a specific question: "Did Dr Sparks provide a reasonable standard of anaesthetic management to Mr Hobson during surgery on 19 November, 2009?" He replied: "Yes. Mr Hobson was a high risk patient who required major emergency surgery at that time. He posed a very unusual and difficult anaesthetic challenge due to the significant compression of his left main bronchus by his spine and due to the requirement for prone positioning during surgery. … The patient was appropriately monitored during the case, and the choice and dosages of anaesthetic drugs and intravenous fluids were also appropriate. The main clinical dilemma in this case was whether surgery should have been allowed to continue given the difficulties in ventilating the patient that were encountered before the severe deterioration that occurred at 21:30. As noted above, the patient had been difficult to ventilate prior to this time due to compression of his left main bronchus, which was exacerbated in the prone position. However, given that the patient's surgery was considered to be sufficiently urgent that it needed to be performed out of hours, and given also that his lung infection would not have been expected to resolve until the compression of his left main bronchus was relieved by surgery, it was reasonable to continue the anaesthetic at that time."
18. He was also asked: "Did Dr Sparks, in his anaesthetic management of Mr Hobson, act in a manner that was widely accepted in Australia by peer professional opinion as competent professional practice, at the time the service was provided?" to which he answered: "Yes. Mr Hobson was a high risk patient who required major emergency surgery on his spine, in the prone position. … The patient was appropriately monitored intraoperatively, and the anaesthetic drugs, dosages and fluid administration were also appropriate. The management of the patient's critical deterioration at 21:30h was appropriate, as was the decision to abandon the procedure at that time. The anaesthetic management of Mr Hobson by Dr Sparks would therefore have been widely accepted by peer professional opinion in 2009 as competent professional practice."
19. Drs Westbrook and Forrest conferred on 7 September 2016, and provided a joint report in which they addressed a number of specific questions.
20. Dr Westbrook somewhat modified his position concerning the timing of the surgery by saying that it was reasonable, in the light of certain findings, to bring forward the second stage surgery, but added that it did not need to take place on the evening of 17 November, and 24-48 hours would have been a reasonable timeframe. (Dr Forrest was of a different opinion, considering it reasonable to proceed with the surgery that night, given the respondent's respiratory condition.)
21. Dr Westbrook also modified his earlier stated opinion concerning the use of the double lumen tube, which he now considered "not an unreasonable decision".
22. The critical question for present purposes was a question numbered 14. The two anaesthetists had answered the previous question concerning the respondent's blood pressure and decreased oxygen saturation at various times during the surgery and said: "At 21:20, Both experts agree that it is difficult to determine exactly what the cause of the plaintiff's low blood pressure was, but it was likely to have been a combination of patient and surgical factors. At that time, however, his oxygenation was adequate."
23. Question 14 was: "In the light of that indication, what steps, if any, should the anaesthetist have taken, particularly including recommending a cessation of the surgery at any of those times?" The answers were recorded as follows: "Dr Westbrook feels that in view of the significant worsening of the plaintiff's haemodynamic state at 20:35, surgery should have been abandoned no later than 20:37, given the concurrent evidence of his worsening metabolic state as evidenced by blood gas analysis demonstrating a severe acidosis. In Dr Forrest's view, given that the plaintiff's surgery was considered to be potentially lifesaving at that time and was well advanced and also given that the period of haemodynamic instability and desaturation were transient at 20:35, it was reasonable to attempt to continue to improve the plaintiff's ventilation and haemodynamic state. At 21:30, however, it was clearly necessary to abandon surgery given the sudden, severe respiratory and haemodynamic instability that suddenly occurred at that time."
24. The anaesthetists were asked, once the surgery had commenced, when it should have ceased (if at all). The following responses were given: "It is the opinion of Dr Westbrook that the surgery should have been abandoned before 20:37 following the episode of hypotension that occurred at 20:30 hours, coupled with the plaintiff's severe and deteriorating metabolic state that was identified at 20:37 hours (by blood gas analysis). Dr Forrest is of the opinion that the surgery should have been abandoned when the plaintiff suddenly became hypoxic and hypotensive at 21:30 hours."
25. Both experts agreed that the most probable cause of the ultimate spinal injury suffered by the respondent was inadequate supply of oxygenated blood to his spinal cord, and that this most likely occurred at around 21:30.
26. At trial, Drs Westbrook and Forrest gave oral evidence in conclave, Dr Westbrook by video link from London. Dr Westbrook again expressed the view that surgery should have been abandoned "certainly at 20:37". Dr Forrest was more nuanced. He said: "Well, with a benefit of hindsight I think you couldn't argue that would have been preferable to abandon the surgery earlier than - than - than at the time that it was abandoned. That's a retrospective interpretation of the events that the anaesthetist was faced with at the time. You've also got to bear in mind that the key imperative for performing this case out of hours in the first place was that the attending doctors felt that if they didn't operate, his respiratory state would continue to worsen because of the compression of his main stem bronchus. And there was a reasonable expectation, I think, that if surgery had not been successful or not been performed to alleviate that obstruction, that the patient would have died from contractible respiratory failure … … So, I think that there was - would have been a strong sense among the - the - the anaesthetists and attending doctors that - that - that surgery should proceed and that all attempts should be made to correct the underlying causes of his metabolic acidosis, which was being exacerbated by the fact that his ventilation proved so difficult in the prone position. And one thing that was done in order to improve his ventilation was to administer muscle relaxants, which had been withheld up until the period between 20 - 20 - 20.20 and 21.30, in order to attempt to improve his - his ventilation."
27. Three orthopaedic surgeons provided reports. They were Dr Richard Johnson and Dr James Wilson-McDonald, both retained by the respondent's solicitors, and Dr Geoffrey Askin, retained on behalf of Dr Gray. Dr Wilson-McDonald is a consulting orthopaedic surgeon in Oxford, UK. They also conferred and provided a joint report.
28. For the purpose of their report, they were asked: "4 Once commenced, when should the surgery have ceased?" They replied: "The experts agree that cardiorespiratory problems arising in spinal surgery with the patient in the prone position occur infrequently but they have all experienced these problems necessitating the cessation of the operation. The experts agree procedures should have ceased when the anaesthetists were unable to maintain the metabolic state, ie satisfactory blood pressure and oxygenation. Dr Wilson-McDonald notes that at 20:37 blood gas analysis demonstrated a deteriorating metabolic state following an episode of hypotension at 20:30. In his opinion surgery should have been discontinued shortly after this."
29. They were then asked: "18 In the light of (a) the information provided by the anaesthetists or (b) information provided by the spinal cord monitor (upon the assumption that the anaesthetists were informing the orthopaedic surgeon of the difficulties that they were experiencing and the spinal cord monitor was informing the orthopaedic surgeon of the inadequacies or absence of traces on the spinal cord monitoring) should the surgery have been ceased and, if so, when?" The short answer given, representing the opinion of all experts, was: "The experts agree yes, when the anaesthetists reached the stage that they were unable to maintain satisfactory cardiorespiratory parameters."
30. These answers reflect an observation in the report of Dr Johnson to the respondent's solicitors, in which he said: "The decision to halt surgery in the presence of hypoxia and hypotension is anaesthetic rather than surgical matter."

The primary judgment

1. The primary judge found that the decision to advance the second stage of the surgery was "perfectly reasonable" and that the decision to continue the operation "at and beyond 20:30" was also "perfectly reasonable". These conclusions are not challenged.
2. He then found that the absence of any (or any effective) spinal cord monitoring after 20:30 was of no significance, as the administration of the vecuronium to the respondent (which neutralised the effectiveness of the monitoring) was critical and took precedence. He held that, until about 20:35, Drs Gray and Sparks were: "226 … in effect, permissibly taking an expectant approach, in the absence of material that indicated only one possible course of action."
3. He held, however, that that position changed very shortly thereafter. Specifically, he found that both Dr Gray and Dr Sparks were negligent in not taking steps to have the surgery terminated "no later than approximately 21.00".
4. His ultimate conclusions were expressed in six paragraphs. He said: "239 Dr Sparks understood that Mr Hobson's need for surgery was urgent. He examined him and formed that view for himself. Dr Westbrook's opinion that that view was 'erroneous' is necessarily second hand and retrospective. Both Dr Westbrook and Dr Forrest in their joint report expressed the opinion that it was reasonable for the surgery to commence. I am however not satisfied that either Dr Gray or Dr Sparks conformed to the relevant standard of care in failing to halt surgery before 21.25. 240 As I have earlier noted, the orthopaedic surgeons in their joint report indicated that the surgery should have ceased 'when the anaesthetists reached the stage that they were unable to maintain satisfactory cardio respiratory parameters'. The orthopaedic surgeons made no precise reference to a time when the surgery should have ceased. Satisfactory cardio respiratory parameters were not being maintained by 20.30. … 242 It is important not to lose sight of the fact that Dr Sparks and Dr Gray were confronted with what was patently a distressing and fraught intraoperative emergency. It is difficult to over-emphasise just how awful it must have been at that time for all concerned. It is clear that Dr Sparks had attempted all of the anaesthetic manoeuvres in his armoury to correct the problem without apparent success. Criticism of these doctors in those circumstances may seem harsh. However, it is not in question that stopping the surgery when no obvious answer to the problems confronting the doctors was presenting itself would have avoided the damage. We know with hindsight that postural adjustment from prone to supine produced immediate resolution of these problems. That was something which in my opinion Dr Sparks and Dr Gray should have foreseen and acted upon. Failure to do so amounted to a want of reasonable care. It was in my view not appropriate to take the risk that something that could not be explained would or might somehow spontaneously resolve or improve. It is no answer to insist that the surgery was lifesaving in circumstances where Mr Hobson's respiratory difficulties at or after 20.30 had deteriorated below his pre-operative condition in ICU."
5. The primary judge went on to restate his conclusions that the absence of effective spinal cord monitoring after 20:30 did not support a finding of negligence against either of the appellants; he considered that to be "a fact of life in the operating theatre". However, he went on to describe the absence of effective spinal cord monitoring as: "243 … a critically significant factor that not only enlivened, but in fact heightened, the need to act conservatively and to proceed expeditiously. It told against the appropriateness of taking an expectant approach when the solution to Mr Hobson's difficulties had not emerged or was not understood." He then said: "264 Dr Sparks was negligent in not advising that surgery should have been abandoned no later than approximately 21.00. He was alive to Mr Hobson's metabolic deterioration which would have caused a reasonably competent anaesthetist to call a stop to the surgery. Had the surgery been paused or halted at that time, and Mr Hobson turned supine, he would not have suffered spinal cord damage."
6. He restated his conclusion that the absence of spinal cord monitoring was irrelevant, but nevertheless held: "268 … the surgery should have been terminated when it became apparent that no reliable indications of the integrity of Mr Hobson's spinal cord health would be available due to the masking effect of that drug [vecuronium] upon informative traces. I have earlier expressed the view, which I maintain, that the absence of spinal cord monitoring, for whatever reason, should have heightened the doctors' need for caution when proceeding without it."
7. The primary judge then turned to the statutory provisions on which the defendants relied. In his consideration of the defence under s 5 I (the full text of which is set out below, and which provides that a person is not liable in negligence for harm that results from the materialisation of an inherent risk) he acknowledged the judgment of Leeming JA in Paul v Cooke (2013) 85 NSWLR 167; [2013] NSWCA 311 in which his Honour had expressed the view that "if a case can conveniently be decided under s 5 I, it should be", but said that this case could not conveniently be decided under that provision. The primary judge said: "248 … the second stage of Mr Hobson's surgery was not attended by an inherent risk that he might suffer a cardiovascular collapse and vascular disturbance causing lower motor neurone injury, such as his anterior spinal artery syndrome, arising out of the circumstances as they occurred. Mr Hobson had a pre-surgical anatomical vulnerability to spinal cord stroke and the effects of hypotension. However, the damage sustained by Mr Hobson was not the materialisation of a risk that was inherent in undergoing posterior instrumented thoracolumbar surgery having regard to his medical condition at the time. … 251 However, Mr Hobson's paraplegia could in the circumstances have been avoided by the exercise of reasonable care and skill. Neurological injury, including paralysis, was an inherent risk of the surgery. A negligent failure to abandon the surgery, meaning a failure to exercise reasonable care and skill, before his paraplegia developed was not."
8. With respect to s 5 O (the full text of which is also set out below, and which, as mentioned above, provides protection from liability in negligence to a professional who provides professional services in a manner widely accepted in Australia by peer professional opinion as competent professional practice) the primary judge referred to the evidence of Drs Manasiev and Forrest, both of whom had expressed their written opinions in the language of s 5 O. He observed that the respondent had adduced no evidence from any suitably qualified expert contradicting the opinions of those experts, and that no submission on behalf of the respondent had been made with respect to s 5 O.
9. Notwithstanding the absence of any evidence to the contrary of that of Drs Manasiev and Forrest, his Honour rejected their opinions. His reasons for doing so were the same as the reasons for which he had found that Dr Gray and Dr Sparks were in breach of their duty of care to the respondent by failing to halt the surgery earlier than they in fact had.

The grounds of appeal

1. Given my earlier stated concurrence with the view of Macfarlan JA that the appeal by Dr Gray should be upheld, it is only necessary now to address those grounds advanced by Dr Sparks.
2. By Grounds 1 and 2 Dr Sparks complains of the manner in which the primary judge dealt with s 5 O of the CLA. By Ground 3 he complains of the treatment of s 5 I of the CLA. By Grounds 4, 5 and 6 he asserts error in the conclusion that Dr Sparks was negligent in failing to call a halt to the surgery earlier than he did. By Ground 7 he asserts error in some respects in the quantification of the damages awarded.

(i) the common law position

1. Although the respondent's claims in the appeal are governed by the CLA, I proceed on the basis that the common law, as it had been declared prior to the 2002 enactment of the CLA, continues to apply other than as modified by the CLA: Dobler v Halverson (2007) 70 NSWLR 151; [2007] NSWCA 335. Relevantly for present purposes, the common law principle is that "the law imposes on a medical practitioner a duty to exercise reasonable care and skill in the provision of professional advice and treatment" (Rogers v Whitaker (1992) 175 CLR 479 at 483; [1992] HCA 58). The standard imposed is "that of the ordinary skilled person exercising and professing to have that special skill". Whether, in any particular case, there has been departure from that standard such as to render the medical practitioner liable in negligence is a matter for adjudication and determination by the court, although guided by the evidence of medical practitioners skilled in the area of medical practice in question: Rogers v Whitaker, p 487; Rosenberg v Percival (2001) 205 CLR 434; [2001] HCA 18 at [7].
2. It may be recognised that both Rogers v Whitaker and Rosenberg v Percival were cases in which the issue was alleged failure by the medical practitioner concerned to make appropriate disclosure of risks associated with the treatment proposed. However, it is clear that the principles stated were intended to extend to other aspects of treatment; for example, in Rogers v Whitaker, the High Court said (at 487): "Further, and more importantly, particularly in the field of non-disclosure of risk and the provision of advice and information … it is for the courts to adjudicate on what is the appropriate standard of care after giving weight to 'the paramount consideration that a person is entitled to make his own decisions about his life'." The Court made a distinction between the application of the principle in cases of alleged failure to warn or inform, and cases of alleged negligence in the administration of treatment, saying (at 489): "Whether a medical practitioner carries out a particular form of treatment in accordance with the appropriate standard of care is a question in the resolution of which responsible professional opinion will have an influential, often a decisive, role to play; whether the patient has been given all the relevant information to choose between undergoing and not undergoing the treatment is a question of a different order. Generally speaking, it is not a question the answer to which depends upon medical standards or practices." (italics in original)
3. In Rosenberg v Percival, Gleeson CJ added to the principle already stated, the following: "7 … In many cases, professional practice and opinion will be the primary, and in some cases it may be the only, basis upon which a court may reasonably act. But, in an action brought by a patient, the responsibility for deciding the content of the doctor's duty of care rests with the court, not with his or her professional colleagues."
4. These observations, in my opinion, are particularly pertinent to the present case. It is difficult to imagine how the primary judge (or this Court) could reach a conclusion as to whether Dr Sparks' decision to allow the surgery to continue beyond some unspecified point earlier than 21:00 or 21:15 failed to meet the standard of the ordinary skilled anaesthetist other than as informed by the evidence of witnesses with appropriate expertise.

(ii) the Civil Liability Act

1. The relevant provisions of the CLA are s 5B, s 5 I and s 5 O. All are contained in Pt 1A of the CLA, enacted with effect from 6 December 2002. Section 5B provides as: "5B General principles (1) A person is not negligent in failing to take precautions against a risk of harm unless: (a) the risk was foreseeable (that is, it is a risk of which the person knew or ought to have known), and (b) the risk was not insignificant, and (c) in the circumstances, a reasonable person in the person's position would have taken those precautions. (2) In determining whether a reasonable person would have taken precautions against a risk of harm, the court is to consider the following (amongst other relevant things): (a) the probability that the harm would occur if care were not taken, (b) the likely seriousness of the harm, (c) the burden of taking precautions to avoid the risk of harm, (d) the social utility of the activity that creates the risk of harm."
2. Section 5 O provides as follows: "5O Standard of care for professionals (1) A person practising a profession (a professional) does not incur a liability in negligence arising from the provision of a professional service if it is established that the professional acted in a manner that (at the time the service was provided) was widely accepted in Australia by peer professional opinion as competent professional practice. (2) However, peer professional opinion cannot be relied on for the purposes of this section if the court considers that the opinion is irrational. (3) The fact that there are differing peer professional opinions widely accepted in Australia concerning a matter does not prevent any one or more (or all) of those opinions being relied on for the purposes of this section. (4) Peer professional opinion does not have to be universally accepted to be considered widely accepted."
3. Also relevant to this appeal is s 5 I, invoked by Dr Sparks, which is in the following terms: "5I No liability for materialisation of inherent risk (1) A person is not liable in negligence for harm suffered by another person as a result of the materialisation of an inherent risk. (2) An inherent risk is a risk of something occurring that cannot be avoided by the exercise of reasonable care and skill. (3) This section does not operate to exclude liability in connection with a duty to warn of a risk."

Section 5 I

1. In Paul v Cooke Leeming JA subjected s 5 I to searching scrutiny. The meaning of s 5 I is, to my mind, obscure. Even more obscure is its purpose. It seems to me that it does little (if anything) more than restate that liability in negligence depends upon a causal connection between the negligence alleged and the harm alleged to have been suffered. In that sense, it is a statement of the obvious. What it might achieve is a short cut to a resolution of the issues: if what occurred could not be avoided by the exercise of reasonable care and skill, there is no harm resulting from whatever negligence might be shown to co-exist with or precede the damage suffered, as required by s 5B. This, perhaps, is what Leeming JA meant at [51] of Paul v Cooke, when he said: "51 … the issue of causation, determined in accordance with s 5D, does not arise once it is determined a claim falls within s 5I …" He held that s 5 I provides a complete answer to any claim falling within Pt 1A of the CLA. Leeming JA (with the concurrence of Basten and Ward JJA) considered that, for a s 5 I defence to be made out, what has to be shown to be unavoidable is "the risk of something occurring", as distinct from the occurrence itself. In that case, the surgery proposed and undertaken always carried a risk of the harm that in fact materialised (intra-operative stroke), and that that risk could not have been avoided by the exercise of reasonable care and skill.

Section 5 O

1. In Dobler v Halverson, at [60]-[61], this Court held that s 5 O operates as a defence to a claim, the onus lying on the defendant to establish the relevant facts. In Paul v Cooke, Leeming JA observed that s 5 O, like s 5 I, provides a complete answer to a claim under Pt 1 A of the CLA (at [41]). It is in that sense that the section operates as a defence. For that reason, when it is pleaded, it is convenient to deal with it first.
2. In McKenna v Hunter & New England Local Health District; Simon v Hunter & New England Local Health District (2013) Aust Tort Reports 82-158; [2013] NSWCA 476 this Court held that s 5 O is directed to: "165 … a practice, that was in existence at the relevant time, here July 2004 …", (bold added) and that, in the circumstances of that case, no such practice had been identified.
3. The circumstances that gave rise to the decision in McKenna may be briefly stated. In 2004 a psychiatric patient was discharged by the health authority that administered the psychiatric institution in which he had been compulsorily detained under then applicable mental health legislation. Shortly thereafter, he killed a friend (Stephen Rose) who was transporting him from NSW to Victoria.
4. Members of Mr Rose's family who suffered consequential nervous shock sued the health authority, alleging negligence in the decision to discharge the patient. Their claims also were governed by the CLA. This Court (by majority) held that the health authority owed the plaintiffs a duty of care in accordance with common law principles, which it had failed to discharge. It was therefore necessary to consider the application of s 5 O. It was in that context that the majority construed s 5 O as set out above. On that construction, the defence failed.
5. Macfarlan JA (with whom Beazley P agreed) said: "165 … It is unlikely, to say the least, that there would have occurred in or before 2004 a number of situations in which there were sufficient features in common with the present case to enable it to be said that there was a practice concerning how such a situation was to be dealt with by a competent medical practitioner." (bold added)
6. An appeal to the High Court of Australia was successful on the ground that this Court erred in finding that the health authority owed the plaintiffs a duty of care; the High Court therefore did not find it necessary to address the construction of s 5 O: Hunter and New England Local Health District v McKenna; Hunter and New England Local Health District v Simon (2014) 253 CLR 270; [2014] HCA 44.
7. I consider that I am obliged to accept McKenna (in this Court) as stating the prevailing construction of s 5 O: Gett v Tabet (2009) 254 ALR 504; [2009] NSWCA 76 at [277]-[279]. But for that constraint, I would have considered that the language of s 5 O makes it plain that "competent professional [here, medical] practice" is intended to denote "the practice of a profession [here, medicine]", and not a specific practice or method of providing the professional services in question. That construction is supported by the absence of the indefinite article in conjunction with "professional practice", and the use instead of the adjective "competent", which to my mind signifies professional practice in a general sense, rather than an identifiable, specific, and discrete aspect of the profession or method of providing the professional service.
8. As construed in McKenna, s 5 O can apply only in limited circumstances, where the defendant can, or seeks to, identify a discrete practice to which he or she conformed. It necessarily excludes unusual factual circumstances, such as occurred in McKenna, and such as occurred in the present case. It does not appear to me that s 5 O was intended to have such limited application. However, as I have said, I consider myself constrained to follow and apply that decision.
9. Failure by a defendant to prove the s 5 O circumstances (however that section is construed) does not conclude the matter. The onus remains on the plaintiff to establish that the defendant failed to provide the professional service in accordance with the standard of the ordinary skilled person practising that profession.
10. The claim is then to be determined by reference to s 5B of the CLA: see Adeels Palace Pty Ltd v Moubarak; Adeels Palace Pty Ltd v Bou Najem (2009) 239 CLR 420; [2009] HCA 48 at [27]. The relevant questions are:

• was there a foreseeable risk of harm arising from the conduct the subject of the claim?;
• was the risk not insignificant?;
• would a reasonable person in the position of the defendant have taken precautions to safeguard against the risk? (It is necessary for the plaintiff to identify the precautions it is alleged ought to have been taken.)

Determination

1. With those legal principles in mind, I turn to the determination of the issues raised on the appeal.
2. In seeking to apply the principles to the present case, it is worth restating, briefly, the relevant chronology. Surgery commenced at about 19:10 or 19:15. At 19:10 and 20:35 the respondent's blood pressure dropped, but recovered. There were identifiable causes of these episodes - the insertion of the double lumen tube and the insertion of the pedicle screws. At about 20:50 Dr Sparks was sufficiently concerned by the respondent's condition to consult two colleagues, one an anaesthetist and one a cardiac surgeon. At about 21:24 the respondent's blood pressure again dropped, causing Dr Sparks to direct cessation of the surgery.
3. The conclusion of the primary judge was that the decision to continue beyond 20:30 was "perfectly reasonable", but that Dr Sparks ought to have directed that the surgery cease at some time before 21:00 or 21:25. It was only in his consideration of causation, with which he dealt appropriately briefly, that the primary judge nominated 21:15 (at the latest) as the time by which surgery should have ceased. He did this in the context of noting that it was uncontroversial that the paraplegia was caused at some time after 21:15 and before 21:30.

Grounds 1 and 2: section 5 O

1. The construction given to s 5 O in McKenna played no part in the primary judge's rejection of the defences under that section. No ground of appeal sought to call in question the correctness of the McKenna construction of s 5 O. However, if, under s 75A of the Supreme Court Act 1970 (NSW), the court were to proceed to its own consideration of the s 5 O issue, it would be necessary to determine what construction to adopt.
2. Senior counsel for Dr Sparks did suggest, during oral argument, that this Court declare that the McKenna construction is wrong. In the absence of any advance notice of that proposal, and any request for the constitution of an enlarged Bench, the suggestion must be rejected.
3. Were the construction of s 5 O that I prefer to prevail, I would uphold these grounds of appeal. Drs Manasiev and Forrest were unequivocal in their evidence that Dr Sparks acted in a manner that at the time was widely accepted in Australia by peer professional opinion as competent professional practice. No countervailing evidence was given on behalf of the respondent. Indeed, it is difficult to see how Dr Westbrook (the respondent's only expert anaesthetist witness) could comment on peer professional opinion in Australia. He practises in the United Kingdom, and gave evidence from London. There was no evidence that he has any Australian experience.
4. Whether Dr Sparks acted in accordance with widely accepted peer professional practice is a question of fact; it is not a question of the kind referred to in Rogers v Whitaker and Rosenberg v Percival, involving determination of whether a medical practitioner failed to conform to standards of the ordinary skilled medical practitioner (in this case, practising as an anaesthetist). Under s 5 O, the task of the court is not to evaluate the merits of the competing views (if there is evidence of competing views) but to determine whether, as a factual matter, the service had the acceptance of peer opinion, even if other peer opinion was different.
5. However, adopting as I consider I must, the McKenna construction of s 5 O, and since, principally because the circumstances of this case were highly unusual, it was not possible for Dr Sparks to identify "a practice" to which he conformed, the s 5 O defence must fail. That is notwithstanding that the overwhelming medical evidence was that his conduct was in accordance with what was widely accepted in Australia as "competent professional practice".

Ground 3: section 5 I

1. Dr Gray's September advice to the respondent makes it plain that there was always a risk that the surgery would result in neurological injury, including paralysis. It is also clear from Dr Sparks' reluctant agreement to participate in the operation that significant risks were involved. Although Dr Sparks did not expressly spell out what those risks were, it is a reasonable inference on the whole of the evidence that they included the very thing that happened.
2. Whether the risk of neurological injury including paralysis was an "inherent risk" for the purposes of s 5 I depends upon whether that risk could have been avoided, by the exercise of reasonable care and skill. Having regard to the primary judge's finding that Dr Sparks was in breach of his duty of care in failing to terminate the surgery earlier than he did, the finding that, by the exercise of reasonable care and skill, the harm suffered by the respondent could have been avoided was logical and inevitable.
3. On behalf of Dr Sparks it was argued that, as in Paul v Cooke, the primary judge erroneously focused on the potential for Dr Sparks to avoid the occurrence rather than risk of the occurrence. True it is that the risk could have been avoided by a decision not to operate at all. That, in the circumstances of the respondent's condition, was not a realistic proposition. Once it is accepted that the respondent's condition warranted the performance of the operation as emergency surgery, and that that surgery carried a risk of paraplegia, it seems to me that this is a rare case, like Paul v Cooke, in which s 5 I applies. I would uphold Ground 3.

Grounds 4, 5 and 6: breach of duty

1. Since satisfaction of the s 5 I criteria is a complete answer to the claim it may be unnecessary to address the remaining grounds. However, even if I am wrong about s 5 I, I have concluded that the evidence does not support the conclusion that Dr Sparks failed in his duty to exercise the skill and care required of a specialist anaesthetist by failing to take steps to ensure that the operation was terminated at any earlier stage than he did. In the present case, the answers to the first and second questions that arise under s 5B are obvious. There was a risk of harm to the respondent from the administration of anaesthesia given his respiratory condition. That risk was both foreseeable and foreseen. The risk was far from insignificant. The issue is whether Dr Sparks ought to have taken precautions against the risk, those precautions being the termination of the surgery at not later than 21:00 or 21:15. That question is to be decided by reference to the four factors set out in sub-s (2) (as well as any other "relevant thing"). In a case of alleged professional negligence "other relevant things" must include the opinions of relevant experts, as envisaged in both Rogers v Whitaker and Rosenberg v Percival as to conformity (or otherwise) with relevant standards.
2. In the light of the rather lengthy exposition of the facts above, the reasons for my conclusion that the evidence did not establish any breach of his duty of care on the part of Dr Sparks may be stated with relative brevity.
3. The central circumstance to note is the parlous condition in which Dr Sparks reasonably understood the respondent to be, pre-surgery. The medical consensus, as at 17 November, was that the respondent needed urgent surgery to ensure his survival. Although Dr Westbrook at one point challenged that view, Dr Sparks' conduct must be assessed in the light of what he had been told by other respected medical practitioners and in the unchallenged finding of the primary judge that the decision to undertake the surgery when it was undertaken was "perfectly reasonable". It was the ICU staff who first drew attention to the respondent's life threatening condition. Dr Sparks was entitled (and probably obliged) to act upon the fears of those experienced medical practitioners, or at least to take them into account. Indeed, as I have noted above, his evidence was that, were the surgery not as urgent as he understood it to be, he would not have anaesthetised a patient in the condition of the respondent. That circumstance permeated his decision-making throughout the entire process, during which he was faced with the unenviable task of balancing two competing, extremely serious, risks: on the one hand, the risk that without the surgery the respondent's survival was in doubt; on the other, the risk that the surgery itself threatened his survival. Initially, on Dr Sparks' assessment, the former outweighed the latter. When he perceived that the balance had changed, he acted appropriately to have the surgery halted. There is no evidence to support a proposition that his assessment in this respect was erroneous, let alone negligently erroneous.
4. Not one of the anaesthetists who reported and gave evidence expressed a view that Dr Sparks' conduct failed to reach the relevant standard. The nearest was that of Dr Westbrook who considered that the surgery should have stopped at 20:37. Even so, Dr Westbrook's opinion was given at a time when he rejected the otherwise generally accepted opinion that the surgery was necessary to ameliorate a life threatening condition. His conclusion about the time at which it should have ceased is coloured by that, now known to be mistaken, view. Moreover, as the passage extracted above at [286] demonstrates, he based the assessment, at least in part, on "[the respondent's] subsequent progress" - that is, on events that post-dated the decision of Dr Sparks - which nobody suggested was or should have been apparent at the time.
5. It is not now in issue that the surgery was reasonably believed to be urgent and lifesaving. The concerns of the ICU staff were expressed to Dr Gray and passed on by him to Dr Sparks. Dr Sparks independently satisfied himself of that circumstance. It was also recognised that the surgery was of a complexity that called for the assembly of a particularly skilled and experienced team of specialists, including the neurophysiologist Dr Lagopoulos. The degree of urgency, together with the need for specialised assistance, may be gauged by the fact that the operation was scheduled to take place out of ordinary operating hours. Further, it cannot be overlooked that Dr Sparks agreed to undertake the anaesthetic role only because of the perceived urgency. His evidence that, absent that urgency, he would not have agreed to anaesthetise the respondent is a further indicator of the dire situation in which the respondent was perceived to be. There is nothing in the evidence that supports doubt about that perception. That also influenced his decision to persist, and his reliance on the two most salient factors, the respondent's blood pressure and oxygenation.
6. In this regard, reliance on subsequent events (the respondent's recovery, and the ultimate successful performance of the second stage surgery, on 11 December) provides no answer: see Moubarak at [31]. Dr Sparks, and the entire medical team, had to work on what they knew at the time, which was that the respondent's condition was life threatening. The finding (in [242]) that Dr Sparks and Dr Gray ought to have foreseen that "postural adjustment" from a prone to a supine position would have produced immediate resolution of the respondent's respiratory problems, and acted on that anticipation, was largely based on what happened after the surgery had terminated and is not sustainable in the light of what is known of the respondent's pre-surgery condition. It does not take into account the extraordinarily painful risk-balancing exercise in which Dr Sparks had to (and did) engage.
7. On behalf of the respondent, specific reliance was placed on the earlier episodes of hypotension and hypoxia as indicating that the surgery should have ceased earlier than it did. Two responses may be made to this. The first is that each episode was explicable by a specific event - the insertion of the double lumen tube, and then pressure being placed on the respondent by the insertion of "pedicle screws". On each occasion, when the cause of the deterioration was removed, the respondent's condition improved. The second answer is that there was no evidence that the pre-existing condition of the respondent (the condition that compelled the expedition of the surgery) had diminished. That it did on his return to the ICU says nothing about what the signs were at the time.
8. Reliance was also placed on behalf of the respondent on an answer given by Dr Barratt in cross-examination, extracted above. This was directed to Dr Sparks' evidence that, in determining to permit the surgery to proceed, he had relied principally on the respondent's blood pressure and blood oxygenation levels: Dr Barratt was asked: "Then in those circumstances, it really wasn't appropriate, was it, to look at the blood pressure and blood oxygen levels alone when making a decision whether to persist or abandon surgery?" He agreed with the proposition contained in the question. The primary judge regarded this answer as "critical". Dr Barratt replied that he agreed with that statement. Again, two answers may be given to the proposition. The first is that other specialist medical evidence was more favourable to Dr Sparks: Dr Forrest, asked a similar question in oral evidence, answered: "Well, these are the parameters that are - that are used routinely in anaesthetic practice to - to guide our management and they're not the only factors that would determine how the surgery would be conducted. But in this particular case, they would be the - the main factors that would be used to determine whether surgery should continue or not."
9. Dr Westbrook, giving evidence concurrently with Dr Forrest, did not dissent from that answer. He had earlier said that blood gas analysis showed evidence of other serious and deteriorating problems, but agreed that those problems were reversible.
10. Dr Manasiev was asked in cross-examination what factors would inform competent professional practice with respect to anaesthetists and the continuance or otherwise of surgery. The transcript records the following answer: "Well, it's the whole gambit [sic - gamut] of all the haemodynamic parameters that you're looking at within a patient. Predominantly, the blood pressure and saturation, which are telling you how the organs are being perfused, but as well as that, all the attempts that are made, in this case, to improve ventilation … it's a complicated gambit [sic - gamut] of numbers and figures that you're looking at." Ultimately, he said: "You wouldn't exclude, but you would give different parameters different weights upon the patient's stability."
11. The second answer to the proposition is that the evidence did not extend to precise identification of what other factors ought to have been considered. More importantly, no conclusion can, on the evidence, be drawn as to what decision would, on the probabilities, have been made in the light of the other considerations. In other words, there is no evident causal connection between Dr Sparks' reliance on those two factors (to the possible exclusion of others) and the injury suffered by the respondent.
12. It has been suggested that, urgent as the surgery may have been, it was not so urgent that the respondent would have died if it were not completed within a few hours. This must be seen in the light of acceptance on behalf of the respondent (and the unchallenged finding of the primary judge) that it was reasonable to undertake the surgery at the time it was commenced, and in the circumstances in which it was commenced. A decision to terminate surgery only partly completed, after anaesthetisation of the patient, is very far from a decision to commence, or not to commence, surgery. It was not, I am satisfied, demonstrated that it was outside the bounds of proper practice for Dr Sparks to persist in his efforts to maintain the respondent's stability in order to allow the operation to proceed to conclusion.
13. The medical evidence does not, in my opinion, support a finding that, in failing to direct the termination of the surgery before 21:28, Dr Sparks failed to exercise reasonable care and skill. The decision Dr Sparks had to make (on a continuing basis throughout the surgery) involved the exercise of clinical judgment. Although, as decided by Rogers v Whitaker, the ultimate determination as to whether the clinical judgment made came within the bounds of the exercise of reasonable care and skill expected of a competent anaesthetist lies with the court, the judgment is one which must, in this case, be guided by the evidence of other medical practitioners with the requisite knowledge and understanding of the issues involved. So much is clear from Rosenberg v Percival, and, indeed, from Rogers v Whitaker. It was not sufficient to say, although it is plainly the case, that, had Dr Sparks directed termination of the surgery prior to the respondent's collapse at 21:28, the injury would not have occurred. The respondent bore the onus of establishing that Dr Sparks' decision not to direct the termination of the surgery before that time represented a departure from the standard of care and skill required of a specialist anaesthetist. That onus was not discharged. The medical evidence falls well short of permitting a conclusion to that effect.
14. Dr Westbrook's opinion that a decision "could have been taken to abandon surgery" earlier than it was abandoned is insufficient to establish that failure to make that decision lay outside the bounds of competent anaesthetic practice. For the purposes of Dr Sparks' appeal, the evidence of the orthopaedic surgeons that the surgery should have been brought to an end "when the anaesthetists were unable to maintain the metabolic state, ie satisfactory blood pressure and oxygenation" or "when the anaesthetists reached the stated that they were unable to maintain satisfactory cardiorespiratory parameters" can be given little (or no) weight. The true import of that evidence, in the context in which it was given, was that Dr Gray was entitled to rely on the advice given to him by Dr Sparks and that the decision lay within the anaesthetic (not orthopaedic) speciality. The answer given carefully (and properly) avoided the expression of opinion by orthopaedic specialists in respect of an anaesthetic issue.
15. It follows that, in my opinion, the primary judge was in error in finding breach of duty on the part of Dr Sparks. I would uphold the appeal and set aside the judgment.

Damages

1. It follows that, in my view, it is unnecessary to determine the appeal so far as it relates to the quantification of damages. It is sufficient to record that, if it were necessary to decide those issues, I would agree with the judgment of Macfarlan JA.
2. The orders I would make are: (1) The appeal by Dr Gray is upheld. (2) The appeal by Dr Sparks is upheld. (3) The judgment against each defendant is set aside. (4) The respondent is to pay the costs of each appellant of both the trial and the appeal. (5) The respondent be granted a certificate under the Suitors' Fund Act 1951 (NSW).

Endnotes

1. Hobson v Northern Sydney Local Health District [2017] NSWSC 589 ("Hobson").
2. The judge upheld one, saying there were 15, which is not clear from the pleading: Hobson at [6].
3. Defence to third amended statement of claim (Dr Gray), 14 November 2016, par 40.
4. Amended defence (Dr Sparks), 10 November 2016, par 23.
5. Fourth Defendant's outline of submissions, 21 November 2016, pars 124-140 (Dr Sparks); Second Defendant's outline of submissions, 22 November 2016, pars 195-202.
6. Dobler v Haloverson (2007) 70 NSWLR 151; [2007] NSWCA 335 at [60] (Giles JA); Sydney South West Area Health Service v MD [2009] NSWCA 343; (2009) 260 ALR 702 at [21]-[25] (Hodgson JA), [51] (Allsop P), [58] (Sackville AJA).
7. Interpretation Act 1987 (NSW), s 35(2)(a).
8. Dobler at [61].
9. Dobler at [55].
10. (1992) 175 CLR 479 at 487; [1992] HCA 58 (citations omitted).
11. Cf now Montgomery v Lanarkshire Health Board [2015] 1 AC 1430.
12. [1957] 1 WLR 582 at 587.
13. [1985] AC 871 at 881.
14. Sidaway at 876.
15. (2001) 205 CLR 434; [2001] HCA 18 at [7].
16. Naxakis v Western General Hospital (1999) 197 CLR 269; [1999] HCA 22 at [21] (Gaudron J), [47] (McHugh J), [81] (Kirby J).
17. Dobler at [61].
18. Cf Qidwai v Brown [1984] 1 NSWLR 100 at 102, dealing with misconduct of a medical practitioner in a professional respect.
19. McKenna v New England & Hunter Local Health District [2013] NSWCA 476; (2013) Aust Torts Rep 82-158 ("McKenna").
20. McKenna at [160] (emphasis in original).
21. Hunter and New England Local Health District v McKenna (2014) 253 CLR 270; [2014] HCA 44 ("Hunter Health District").
22. (1998) 194 CLR 395; [1998] HCA 48 at [56].
23. (1981) 146 CLR 336 at 410; [1981] HCA 4.
24. [2011] NSWCA 59 at [3] (Beazley and Tobias JJA agreeing).
25. Hunter Health District at [12].
26. See CEMEX Australia Pty Ltd v Takeovers Panel (2009) 177 FCR 98; [2009] FCAFC 78 at [94]-[95] (Ryan, Jacobson and Foster JJ).
27. (2013) 85 NSWLR 167; [2013] NSWCA 311.
28. Civil Liability Act, s 5I(3).
29. Paul v Cooke at [80].
30. Hobson at [196].
31. Hobson at [38], par 7 of Dr Westbrook's supplemental report of 21 October 2012.
32. Hobson at [39].
33. Hobson at [59].
34. Hobson at [224].
35. Affidavit of Stephen Barratt, 12 November 2015, at Hobson [57].
36. Hobson at [226] (italics added).
37. Hobson at [240].
38. Tcpt, 14/11/16, p 264(27).
39. Tcpt, p 265(24).
40. Tcpt, p 265(50).
41. Tcpt, 08/11/16, pp 103-104
42. Hobson at [242].
43. Fourth defendant's outline of submissions, 21 November 2016, par 133.
44. Hobson at [259].
45. Report of Dr Forrest, 26 October 2013, pp 5-6.
46. Report, pp 3-4.
47. Report, p 5.
48. Tcpt, 14/11/16, p 268(33).
49. Report of Dr Manasiev, 26 October 2016, p 3.
50. Report, p 3.
51. Report, p 4.
52. Tcpt, 14/11/16, p 294(28).
53. Hobson at [122].
54. Hobson at [248] and see [249(2)].
55. Report of Joint Orthopaedic Expert Teleconference Conclave of Drs Johnson, Askin and Wilson-MacDonald, 7 October 2016, p 6.
56. Affidavit, Randolph Gray, 7 November 2016, p 5.
57. Tcpt, 07/11/16, p 40(15).
58. Report, p 4.
59. Tcpt, 14/11/16, p 295(5).

Amendments 14 May 2018 - [214]: Formatting correction. DISCLAIMER - Every effort has been made to comply with suppression orders or statutory provisions prohibiting publication that may apply to this judgment or decision. The onus remains on any person using material in the judgment or decision to ensure that the intended use of that material does not breach any such order or provision. Further enquiries may be directed to the Registry of the Court or Tribunal in which it was generated. Decision last updated: 14 May 2018