Waaka v Accident Compensation Corporation

IN THE DISTRICT COURT AT WELLINGTON DECISION NO. 8 5 /2008 UNDER The Injury Prevention, Rehabilitation and Compensation Act 2001 IN THE MATTER OF an appeal pursuant to section 149 of the Act (Appeal No. AI 465/03 BETWEEN IZAYA WAAKA Appellant AND ACCIDENT COMPENSATION CORPORATION Respondent Hearing: 4 March 2008 Appearances: Ms S Thistoll for appellant Ms A Douglass for respondent Judgment: 21 April 2008 RESERVED JUDGMENT OF JUDGE D A ONGLEY [1] The main question in this appeal is whether injury from ischaemic hypoxic hypoglycemic collapse of a baby of two months following surgery was substantially caused by a failure to provide an effective post-operative plan to ensure early response to any post-operative problems. [2] Izaya Waaka was born on 26 November 2001. In January 2002 his General Practitioner diagnosed a right inguinal hernia and Izaya was referred to Mr Samiuela Tonga, General Surgeon at Timaru Hospital. Mr Tonga reviewed Izaya at Timaru Hospital on 17 January 2002 and arranged for him to have his hernia repaired by way of a herniotomy. He repaired the hernia on 29 January 2002 when Izaya was two months old and weighed approximately 5 kg. IZAYA WAAKA V ACCIDENT COMPENSATION CORPORATION DC WN DECISION NO. /2008 [21 April 2008] [3] The surgery was uneventful and Izaya was admitted to the recovery room at 1515 hours where his vital signs were noted to be within normal limits. Further recordings were taken of his vital signs at 1600 hours and were also noted to be normal. The next and last entry in the medical notes on the day of surgery was probably written by a staff nurse from the ward: Slept post op. Has B/F [breast fed]. IV luer removed. Dx [discharged] home with Mum at 2000hrs. For OPD [Outpatients department] 2 wks, dressing to remain on for 1 wk. [4] There was no plan for the baby's condition to be monitored following surgery. On 2 February 2002 Izaya was readmitted to Timaru Hospital after his mother found him unconscious and blue. He was found at about 9.00 am but the ambulance did not arrive until at 10.30 am because the family did not have a telephone and lived in a relatively isolated location. The St John Ambulance report noted that at approximately 0900 hours he had been found very pale, cyanosed and possibly having suffered a seizure. When the ambulance arrived, Izaya was described as "Unconscious. Nil response. Skin hot, pale, dry". His eyes were not opening, his pupils were dilated and he was not responding, even to painful stimuli. His heart rate was noted to be 147 beats per minute, his respirations were 62 per minute and his temperature was 38.9C. [5] Izaya was admitted to Timaru Hospital at 1115 hours where intensive resuscitation was commenced. Blood tests indicated severe hypoglycaemia and dehydration. He was transferred to Starship Hospital in Auckland later that evening. Investigations done at Starship Hospital showed that the cause of Izaya's severe illness was not related to any problem from the inguinal hernia repair. Further exploratory surgery at Starship Hospital revealed no obvious cause for his collapse. He was treated with antibiotics, stabilised and discharged back to Timaru Hospital on 19 February 2002. [6] Tragically, Izaya has been left with profound mental retardation, cortical blindness and a severe seizure disorder. [7] Izaya's parents lodged an ACC claim for medical misadventure claiming Izaya's injuries were caused by ischaemic hypoxic hypoglycemic collapse following sepsis from hernia repair. However infra-abdominal sepsis was excluded following a laparotomy at Star Ship hospital and no other cause for Izaya's collapse could be positively identified. Dr Richardson's opinion [8] The principal evidence on which the appellant replies is an opinion from Dr Vaughan Richardson, Paediatrician. The main text of the letter needs to be set out in full in order to understand the basis for the claim of medical error, which does not concern the surgical procedure itself but failure to monitor the baby's progress following surgery. Dr Richardson wrote on 26 June 2007: "I believe that one of the main concerns I had about this surgery being performed on such a young infant at a secondary hospital (Timaru) rather than the tertiary hospital (in this case Christchurch Hospital) are not just those of operative technique and paediatric anaesthetic expertise but also the whole care 'package' which would include follow-up and understanding of the difficulties faced by such a young infant following such surgery. I do not have evidence that the technical aspects of the surgery or anaesthetic were the cause for the subsequent near-fatal collapse with severe hypernatraemic (high sodium) dehydration, bile stained stomach contents, hypoglycaemia and seizures. However I believe that he should not have been discharged on the day of surgery - not only because of his age but also because of the distance he was away from help if complications developed. Our local (Wellington) practice does allow discharge on the day of operation in babies over 4 weeks of age (if born at term) in certain circumstances - but in reality, babies under three months stay in hospital over night to ensure feeding and breathing have fully recovered. If early discharge was to be considered in an individual baby, the anaesthetic would contain no opiates (morphine or similar) and the patient would have to be able to return for assessment to the hospital at short notice. While many herniotomies are performed in young infants, this surgery can be followed by apnoea (breathing cessations) poor feeding and delayed intestinal motility and quite a number of babies require intravenous fluid and pain relief following this - often up to 48 hours following surgery. I have no doubt hat this catastrophic outcome would not have occurred had Izaya not had he surgery. The outcome was unexpected and rare but I believe that this was due to him being discharged - without an adequate plan - too early following surgery. There is no evidence for any other coincidental cause being responsible other than poor oral intake and a possible ileus (delayed intestinal motility) due to inadequate recovery from the surgery prior to discharge. I feel that the early discharge from hospital following surgery in his case led to this poor outcome. (Causal link) A decision to discharge on the evening following such surgery in a young infant has to made very carefully with a plan made about expected progress and what action to take if this progress is not met. This would be a simple plan related to feeding and sleeping and urinary output for example. No such plan was in place and Izaya has been permanently damaged by this failure. In conclusion I believe that this case does meet the criteria for error. I believe that if such surgery is to be contemplated in a secondary unit (e.g. Timaru) in a young baby there needs to be a clear post-operative plan in place to ensure full recovery has occurred together with a back-up plan if problems develop. Early discharge from hospital increases the chance of delayed diagnosis of such problems together with a delay in resuscitation and definitive treatment. There is no evidence of an appropriate discharge plan with Izaya and I believe this represents an error on the part of the responsible health professional and those caring for the infant at the time of discharge." [9] Dr Richardson's opinion was obtained for the hearing of this appeal and was not available to the Reviewer who dismissed the review application. The argument at review was rather different from the argument on appeal. The search at review was for a specific cause that could be associated with the events of surgery, or a non- associated cause such as vaccination aftermath or sudden infant death syndrome. Medical reports and opinions 10] The medical reports or opinions concerning the cause of Izaya's condition are set out in the following paragraphs in the order in which they were received. [11] Mr Tonga wrote on 6 August 2002 to the medical advisor of the medical misadventure unit. He said: "... The history I received was that Izaya was slightly off his food on 30 January 2002, the day after his operation, he was well for the rest of that day 30/1/02) and from then on until the evening of 1 February 2002 when he became irritable. He became pale and floppy with shallow respiration. His abdomen was soft and his operative wound was healing well, showing no signs of infection." Mr Tonga concluded: "Given the facts and the results of the investigations, I do not believe that Izaya's unfortunate illness can be directly attributed to his inguinal hemia repair or the anaesthetic on 29 January 2002." [12] Dr Pringle, paediatric surgeon and Professor of Paediatric Surgery, in a report of 17 November 2002, said that he was in no doubt that Izaya's severe handicap was clearly related to the acute episode that he suffered on 2 February 2002. That much has never been disputed. It is an accepted fact that his severe handicap was not pre- existing but was caused by illness on 2 February. The question is whether there was a causal nexus between that catastrophic event and the surgery four days before. Dr Pringle said that there was absolutely no evidence that the anoxic insult was in any way related to the inguinal herniatomy. He described the anoxic insult as being so severe that it not only caused injury to his brain but also significant injuries to his liver, his kidneys, his heart and his gastrointestinal tract mucosa. Dr Pringle considered that the event of 2 February was a near miss sudden infant death syndrome. He found no evidence to support diagnosis of sepsis, given that blood cultures taken from the bone marrow prior to the introduction of any antibiotics grew no organisms. Dr Pringle said: "Given the total lack of any evidence that there was any connection between the child's illness on the 2nd of February, and his herniotomy four days earlier, I find no evidence to support a claim for medical misadventure. However, if a diagnosis of a 'near-miss sudden infant death syndrome' does prove to be correct, then depending on the circumstances surrounding the initial finding of this child at 9.00 am on the 2nd of February (incidentally a Saturday morning), this incident may possibly meet the criteria for the definition of an accident." [13] That last paragraph followed some earlier reservations that Dr Pringle raised about the possibility of an unexplained delay in reporting Izaya's condition. There was no telephone in Izaya's home. After his mother found he was unwell, she had to drive to another house in order to ring the hospital. There was a time delay that Dr Pringle appeared to find significant, suggesting that he was of the view that if there had been more immediate access to treatment the consequences might have been less severe. [14] However the focus of the report was on the possibility of sepsis caused by the surgery, or any other physical cause that could be connected with the surgery. Sepsis was ruled out and no surgically related cause could be found. At that stage no attention was given to the question of a duty to keep this two month old infant under review following surgery. The Corporation received a medical report from its medical misadventure clinical advisor and wrote to the family on 14 January 2003 declining cover. The decision to decline was based on the respondent's medical advisor's report, as follows; "In Izaya's case it is impossible to show that he has suffered a physical injury as a result of medical treatment. Izaya's injury is undoubtedly a result of his collapse on 2 February 2002 However, it is impossible to show that Izaya's collapse is related to the right herniotomy on 28 January 2002. We do not have any evidence that Izaya developed sepsis following his right herniotomy. Investigations performed in Starship hospital did not establish any cause for Izaya's collapse and subsequent injury." [15] The family lodged a review of ACC's decision and the Corporation sought further advice from Mr James Shaw, Clinical Professor of Surgery, and Professor Carl Burgess, Professor of Medicine and Clinical Pharmacology. [16] Mr Shaw agreed that the severe handicaps Izaya suffered were a result of the acute episode occurring on 2 February 2002, however he could find no relation between this acute episode and the inguinal hernia repair operation four days earlier. Mr Shaw noted that the herniotomy was uneventful and Izaya was discharged home later that day. He was noted to be more grizzly than usual for two days and than appeared to return to his normal self, but was found critically ill the following morning. He was resuscitated at Timaru Hospital and transferred to Starship Paediatric Intensive Care where infra-abdominal sepsis was excluded following a laparotomy. Once he was stabilised there was possibly an ECG abnormality, possibly a cardiac abnormality, possibly a metabolic problem and it was clear that he had suffered a major cerebral insult. Mr Shaw said: "There would appear to be little doubt that the severe handicap this child has suffered is a result of the acute episode which occurred on the 2nd February, however, there is no evidence whatsoever that this was related to his inguinal hernia repair as this was never noted to be a problem after the acute episode and he underwent a laparotomy which failed to show any abnormality, in particular no abnormality associated with the hernia repair or in fact any other septic problem. Overall I can see no connection between the child's severe illness on the 2nd February and the herniotomy four days earlier. I can see no evidence to support a claim of medical misadventure. In fact the resuscitation performed at Timaru Hospital clearly has been of an A Plus standard." [17] Professor Burgess wrote on 9 July 2003 stating that vaccination can on occasions lead to encephalopathy and very occasionally to mental retardation, but there was no evidence that lazaya had a severe reaction to his vaccinations. There was no temporal connection and no sign of a systemic reaction. [18] Dr Richardson first gave an opinion on 18 November 2003. His more recent letter of 26 June 2003 is referred to earlier in this judgment. He was the only practitioner to consider the question of adequate post-operative oversight and there has been no contradictory evidence on that point. The other opinions had considered the possible causes of sepsis or vaccination, and had addressed the herniotomy and nursing up to the time of discharge from Timaru Hospital. Dr Richardson questioned whether the surgery should have been performed at Timaru Hospital on a baby of two months. He identified risks such as loss of a testes or anaesthetic problems, which are mostly eliminated if a paediatric surgical team perform this surgery in very young infants. Then he wrote: "The next potential problem is that he was discharged home at 2000 hrs on the day of surgery. Some infants have breathing and feeding issues following surgery at this age and I believe that it would have been wise to keep him in the hospital until the following morning at least. I am not reassured by the notes before me that his feeding returned to normal following this operation. In fact there are a number of findings that make me feel that his collapse was due to significantly reduced intake. These findings include his apparent weight loss, his very high sodium level and his very low glucose level. In addition very low glucose levels lead to convulsions and that [was] a very likely precursor to Izaya's final collapsed state. . . .. In conclusion From the evidence before me, I believe that his profound illness was most likely due to poor intake in the days after the surgery (or perhaps just over the last 24 hours) leading to hypernatraemic dehydration and severe and prolonged hypoglycemia. This situation then led to seizures and contributed to his poor outcome - partly due to the fact that he was so far away (in time) from the resuscitative help at Timaru Hospital. The collapse was associated with hypoxaemia and circulatory collapse leading to the cascade of gut, liver, kidney and respiratory failure and caused permanent brain damage. While I do not believe that the surgery was directly responsible for his state now, I believe that his reduced intake probably did occur partly because he had just returned from surgery. It appears that he was not reviewed by any health professional in the time between his operation and collapse, and if he had been it might have been noted that his condition was not as good as it should have been. I also do not believe that he would have fed normally in the hours before he collapsed and certainly not at the 0600 hr feed that morning. I would have expected him to look irritable and disinterested at that time and may have already developed increased work of breathing. There is no evidence before me that there was error on the part of any health professional or organisation involved. The question is therefore if Izaya's illness was the result of medical mishap. He had a herniotomy performed as planned and this appeared at the time and subsequently to have been without direct complication. I would have expected that those feeding him would have noted that he was not feeding as well as he used to - and possibly less requently. If he was in discomfort from the wound and the handling involved in feeding made it more difficult for him then this could be considered partially to blame. It appears however that his family were not too concerned about him until the collapse - whether that was because he was not complaining or that he truly seemed to be feeding and reacting normally I cannot say. I can understand why his family find it difficult not to blame the surgery for his outcome. Overall I feel that the surgery did give rise to a cascade of problems with him that ultimately led to the collapse. A review prior to that could have prevented this outcome so that on the balance of probabilities I believe that about half of the poor outcome should be put down to 'lack of proper recovery from the surgical procedure'. Delays in recognising the problem and getting help rapidly enough (at least partly due to geography) contributed to the rest of the poor outcome. [19] In that letter, Dr Richardson considered the collapse as a rare and severe outcome of surgery properly performed. The cause proximate to the outcome would have been reduced intake leading to possible convulsions but in any case a metabolic collapse that would not have occurred but for the surgery. Dr Richardson considered that if he had been reviewed by a health professional in the time between his operation and collapse, it might have been noted that his condition was not as good as it should have been. It would follow that he could have been readmitted and kept under observation. [20] In his letter of 26 June 2007 Dr Richardson gave further consideration to his view that there might have been inadequate post-operative oversight. He said that the whole care package should include follow-up and understanding of the difficulties faced by such a young infant following such surgery. He believed that Izaya should not have been discharged on the day of surgery, both because of his age and also because of geographical distance and impossibility of quick response. He said that the Wellington practice was to keep babies under three months in hospital over night to ensure feeding and breathing have fully recovered. Herniotomies can be followed by apnoea, poor feeding and delayed intestinal motility and quite a number of babies require intravenous fluid and pain relief, often up to 48 hours following surgery. Dr Richardson had no doubt that this catastrophic outcome would not have occurred had Izaya not had the surgery. The outcome was unexpected and rare, but was due to his being discharged, without an adequate plan, too early following surgery. There was no evidence for any other coincidental cause. [21] On that basis, Dr Richardson believed that the case meets the criteria for error. Recognising that his view was critical of performing herniotomy surgery in Timaru hospital, he said that if such surgery for a young baby is to be contemplated in a secondary unit, there needs to be a clear post-operative plan in place to ensure full recovery has occurred together with a back-up plan if problems develop. Early discharge from hospital increases the chance of delayed diagnosis and delay in resuscitation and definitive treatment. [22] The Corporation asked Mr Shaw to comment on Dr Richardson's opinion. In a short note of 30 November 2008, Mr Shaw did not attempt to contradict Dr Richardson's view that the outcome might have been prevented by a plan to keep Izaya's condition under review in the days following surgery. He repeated that there was no surgical error in the surgery performed by Dr Tonga. He said that Hospital Management was responsible for policy regarding rules for age limits for surgery in young patients. Mr Shaw's note did not contradict anything Dr Richardson had written, but raised the question whether the responsibility rested with the surgeon or with hospital management. Respondent's submissions [23] Ms Douglass for the respondent pointed to the investigations that excluded the possible causes of intra-abdominal sepsis, vaccination reaction or underlying metabolic disorder. It was submitted that no diagnosis has been ascertained and that temporal association between the herniotomy operation and the collapse four days later is insufficient to establish on the balance of probabilities the cause of the collapse. 24] Ms Douglass noted that Dr Richardson changed his opinion, and she submitted that the criticisms contained in Dr Richardson's second report do not support on the balance of probabilities a causal link being established. Dr Richardson's view that the catastrophic outcome would not have occurred had Izaya not had the surgery, is speculative and relies on a temporal association. Ms Douglass referred to evidence that there had been no sign of impending collapse. It was noted by Dr Richardson that the family were not too concerned about Izaya until the collapse, whether because he was not complaining or whether he truly seemed to feeding and reacting normally. [25] It was submitted that there is no evidence to suggest how the surgery may have caused the conditions leading to Izaya's collapse. While there was no direct enquiry about the anaesthetic process, the extensive investigation raised nothing to question the actions of the anaesthetist. [26] Section 33 of the Act states that medical error does not occur solely because desired results are not achieved or because subsequent events show that different decisions might have produced different results. The onus lies with the claimant. Recently in ACC v Ambros (CA 172/05) [2007] NZLR 304 the Court of Appeal confirmed that a claimant is required to prove causation on the balance of probabilities. A close proximity test was specifically rejected. The Court said that there must be sufficient material pointing to proof of causation on the balance of probabilities for a Court to draw even a robust inference on causation. Risk of causation does not suffice. The respondent says that the risk of causation is not sufficient to establish proof of causation or to draw a robust inference regarding causation. Appellant's submissions [27] Ms Thistoll for the appellant submitted that physical injury including brain damage, cortical blindness and a severe seizure disorder are the result of medical error through failure of a registered health professional to observe a standard of care and skill reasonably to be expected in circumstances where there was a material risk of complications occurring following surgery on a very young baby and no evidence that the baby was reviewed prior to his discharge from hospital or any discharge advice given to the baby's parents. It was submitted that, where a material risk exists, a patient or guardian should be warned about that risk so they may take appropriate action should that risk eventuate. In the absence of documentary evidence of a warning being given it must be inferred that none was given. [28] Ms Thistoll also submitted that the decision to undertake surgery on a baby as young as Izaya in a secondary hospital amounted to a medical error. The surgeon was not a paediatric surgeon. In Mr Richardson's opinion an infant of this age should have been referred for surgery to Christchurch Hospital where risks of surgery could have been properly managed. Ms Thistoll submitted that the surgeon had a non-delegable duty to provide care to Izaya from the time he was admitted to Timaru Hospital until the time he was discharged. Care at the time of discharge should have included a suitable post-operative plan. [29] Ms Thistoll referred to a discussion by Judge Cadenhead in Estate of Gavin Thomas (381/2004) where he referred to the judgment of Mason J in the High Court of Australia in Burnie Port Authority v General Jones Ply Lid (1994) 120 ALR 42 and discussed the non-delegable nature of the duty of care in circumstances where there is a particular responsibility for the safety of the claimant. Mason J referred to the "the central element of control" and special dependence or vulnerability on the part of the person claiming. I agree that such a relationship exists in the present case where the appellant was utterly dependent on the care of the surgeon during the herniotomy and immediately after. [30] Ms Thistoll submitted that the failure of the surgeon to review Izaya on his discharge from Timaru Hospital, to provide any discharge advice to his parents, or to ensure that those tasks were undertaken by some other medical practitioner, was directly responsible for Izaya's collapse and cascade of problems which ultimately led to his brain damage. There was no primary record of observations of normal feeding and bowel motions in Izaya's hospital notes. The only entries after his operation were made by nursing staff. Dr Richardson noted in his report that there was evidence of weight loss, and that he would have expected that those feeding him would have noted he was not feeding as well as he used to and possibly less frequently. The weight loss was said to be 800g from the time of his operation to his admission to Starship Hospital four days later. Dr Richardson stated that he was not reassured by the notes that his feeding returned to normal following this operation and that there were a number of findings that made him feel that his collapse was due to significantly reduced intake. Those findings included apparent weight loss, his very high sodium level and his very low glucose level. Very low glucose levels lead to convulsions and that were a very likely precursor to Izaya's final collapsed state. Dr Richardson therefore reached the conclusion that Izaya's profound illness was most likely due to poor intake in the days after the surgery, or over the last 24 hours, leading to hypernatraemic dehydration and severe and prolonged hypoglycaemia. He was so far from resuscitative help at Timaru Hospital that the crisis could not be treated in time. The collapse was then associated with hypoxaemia and circulatory collapse leading to cascade of gut liver, kidney and respiratory failure and caused permanent brain damage. [31] Ms Thistoll also submitted that there was a negligent failure to prescribe analgesia, which may have contributed to his being unable to feed because of pain, resulting in dehydration and collapse. There is however no specific medical opinion directed to that possibility. [32] Ms Thistoll submitted that the failure to provide any discharge information to Izaya's parents meant that they were not in a position to recognise that he may have been deteriorating and required immediate medical attention prior to his collapse. Izaya's mother reported that he was more irritable than usual after going home but that she was not greatly concerned until his collapse. Had she been told prior to Izaya's discharge that irritability could be an indictor of more serious illness then she would have had to opportunity to have him reviewed by medical staff in time to prevent his collapse. There is no record of Izaya's mother having any instructions on his post operative care and about what potential complications she should look out for and when she should be concerned and seek medical assistance. It is common sense that an infant of only two months who is still being breastfed would need to be observed closely following any surgery and that its mother should be given explicit instructions on possible post-operative complications and what to do if they occur. These instructions should include what to do if the baby became irritable and stopped feeding as this could result in dehydration, a potentially dangerous event for a very young baby. Decision [33] The claim is to be determined under the law as it stood before s 33 of the 2001 Act was amended on 1 July 2005 to include treatment injury including organisational error. [34] In Dr Richardson's opinion Izaya needed a clear post-operative plan, and there has been no evidence for any cause of his collapse other than poor oral intake and a possible ileus (delayed intestinal motility) due to inadequate recovery from the surgery prior to discharge from hospital. If that is correct, it would follow that failing to put a plan in place would have increased the risk of failing to recognise the need to stabilise Izaya's condition. [35] The question of error is whether it was appropriate to discharge the baby without a post-operative plan. Dr Richardson's opinion was that surgery can be followed by apnoea, poor feeding and delayed intestinal motility, and that quite a number of babies require intravenous fluid and pain relief, often up to 48 hours following surgery. Dr Richardson considered that, if early discharge is to be considered for an individual baby, the anaesthetic would contain no opiates and the patient would have to be able to return to the hospital for assessment at short notice. It follows that post-operative care should have been available in this case. I accept that evidence and find that there was medical error in failing to provide a post- operative plan. [36] As to causation consequent upon failure to provide a plan, the appellant submits that it is more probable than not that the cause of the collapse was a post- operative complication, and that some signal of that would have been detectable if there had been an effective post operative plan. [37] That view is logically consistent with the medical evidence. Izaya was only two months old when he was discharged following his herniotomy and remained with his family in a fairly isolated location where there was no arrangement for his progress to be monitored. It seems probable that there would have been some sign of developing failure and there should have been an opportunity for the baby to be returned to the hospital where he could have been observed. In that case, his acute condition should not have been allowed to occur. A plan could have required medical examination shortly after discharge, and the baby's progress could also have been more effectively monitored by his parents so that early intervention could have been requested if there were adverse signs that were post-operatively significant. Without a plan, the parents were not to know of the risks following surgery and the level of concern to attach to any problems that might not otherwise appear to be significant. [38] There is no body of evidence addressed to the probable effectiveness of an appropriate plan. Dr Richardson said that there should have been follow-up and understanding of the difficulties faced by such a young infant following such surgery. He said that, if Izaya had been reviewed by a health professional in the time between his operation and collapse, it might have been noted that his condition was not as good as it should have been. There is no evidence contradicting that view. In his letter of 26 June 2007 Dr Richardson wrote: "A decision to discharge on the evening following such surgery in a young infant has to made very carefully with a plan made about expected progress and what action to take if this progress is not met. This would be a simple plan related to feeding and sleeping and urinary output for example. No such plan was in place and Izaya has been permanently damaged by this failure." [39] It is also possible that the signs of post-operative complication might not have been observed, or might not have been observed in time. There is of course the need to avoid speculation in considering what the likely outcome would have been had he received appropriate care. What is to be considered is the probable outcome if there had been an effective plan, either for Izaya to remain in hospital for continued observation or otherwise for follow up examination and for the family to know what signs to look for and when to have Izaya's condition checked. If there had been an effective plan, there would have been an increased likelihood of recognising poor oral intake, or delayed intestinal motility. If the plan were designed to be effective Izaya should have been carefully monitored once any adverse signs were recognised and he would have received immediate attention in the event of distress. I find on this evidence that there would have been a real likelihood of deterioration being recognised and a real opportunity of intervention. [40] In ACC v Ambros (above) the Court of Appeal said that the requirement for a plaintiff to prove causation on the balance of probabilities means that the plaintiff must show that the risk of causation or probability of causation is higher than 50 per cent. Mere risk of injury caused by medical error is not enough. The Court rejected a reverse onus, but accepted that there is a tactical burden that passes to the defendant when some evidence of causation has been adduced by the plaintiff. In stating that conclusion, the Court adopted Lord Mansfield's maxim in Blatch v Archer (below) in the following paragraph in Ambros: [59] In Canada in Snell v Farrell, Sopinka J, for the Court, pointed out that in many malpractice cases the facts lie particularly within the knowledge of the defendant. In these circumstances very little affirmative evidence on the part of the plaintiff will justify the drawing of an inference of causation in he absence of evidence to the contrary and even though positive or scientific proof of causation has not been adduced - see at 300. Even if some evidence o the contrary is adduced by the defendant, the trial judge is entitled to take account of Lord Mansfield's famous precept in Blatch v Archer (1774) 1 COWP 63 at 65; 98 ER 969 at 970: It is certainly a maxim that all evidence is to be weighed according to the proof which it was in the power of one side to have produced, and in the power of the other to have contradicted. [41] Dealing further with the weighing of evidence, the Court said: [67] The different methodology used under the legal method means that a court's assessment of causation can differ from the expert opinion and courts can infer causation in circumstances where the experts cannot. This has allowed the court to draw robust inferences of causation in some cases of uncertainty - see at [32] above. However, a court may only draw a valid inference based on facts supported by the evidence and not on the basis of supposition or conjecture - see, for example, Jones v Great Western Railway Co (1930) 47 TLR 39 at 45 and Smith v Auckland Hospital Board [1965] NZLR 191 at 214 (CA) per McGregor J and at 220 per Gresson J. Judges should ground their assessment of causation on their view of what constitutes the normal course of events, which should be based on the whole of the lay, medical, and statistical evidence, and not be limited to expert witness evidence - see Khoury at 203. For a more detailed discussion on inferences, see Khoury at 39 - 43 and 143 - 228. [42] There was no evidence that the effect of surgery and anaesthesia on an infant of two months could not have resulted in Isaya's collapse through a cascade of events including dehydration secondary to a poor intake for some time prior to his collapse. Anaesthesia was not without risk although the evidence does not spell out what the risks might have been. The surgeon recorded that he advised the parents that he would proceed with the operation provided the anaesthetist was happy to anaesthetise Izaya because of his young age. In relation to Wellington practice, Dr Richardson said that if early discharge was to be considered for a baby under three months, the anaesthetic would contain no opiates and the patient would have to be able to return for assessment to the hospital at short notice. Those precautions and responses were not available to Izaya. [43] In this case the respondents have not put forward evidence that a plan would have had less than a 50 percent chance of avoiding the adverse outcome. In my view, the most important aspect of assessing the evidential or tactical burden in this case is that there was no evidence to contradict Dr Richardson's opinion that post- operative risks to such a young infant had to be considered in the ordinary course. The paediatric experts in this case were Mr Pringle, paediatric surgeon, and Dr Richardson, paediatrician. The evidence of the other surgical specialists concerned the adequacy of surgery rather than the post-operative care concerns of a two month old infant. Mr Pringle was not asked to comment on Dr Richardson's opinion of the failure of post-operative care and its consequences. Mr Shaw was asked to comment but he did not address that aspect of error and causation. The possibility of a purely coincidental near-miss sudden infant death syndrome was suggested but not evaluated in comparison with the possibility of post-operative complication. [44] Dr Burgess was asked to address the issue of whether the brain damage may have been due to the side effects of live vaccines given prior to the general anaesthetic. He rejected that possibility because there had been no severe reaction to vaccinations. He said that it is usual for encephalopathy to occur soon after the vaccination and it is usually accompanied by the patient having a systemic reaction to the vaccine. The opinion appeared to leave open a possibility, but went no further. Vaccination remains one of the possible contributing causes. [45] I find on that balance of probabilities that Izaya's collapse was brought about by a post-operative complication of the kind described by Dr Richardson that could probably have been detected at an earlier stage and could probably have been averted if there had been an effective post-operative plan. [46] I find that Izaya was still within the scope of treatment when he collapsed. Accepting Dr Richardson's view that there should have been a discharge plan, and accepting that Izaya's post-operative well-being remained the responsibility of the hospital in the short term, the evidence is that treatment should have been available to him but was not. In Roborgh v ACC (High Court, Wellington CIV 2003-485- 1477, 27 April 2004) Ronald Young J) decided that "treatment" should not be defined narrowly but extended over the period of time required for proper treatment of a premature baby. This case is similar because the baby was within the range of time and circumstances during which he should have had proper post-operative treatment available to him. In Roborgh (187/07) when the medical error appeal was heard in the District Court, error was not found because a screening test had excluded the need for further examination of an infant who suffered retinopathy of prematurity. The evidence in that appeal was that, following the clear screening result, the occurrence of the condition was so rare that the ophthalmologist did not have a duty to conduct a specific examination in the months following the screening test. By contrast, in the present case the relevant time for special care to be taken was a short post-operative period. The possibility of a post-operative complication had not been excluded by any process such as a screening test. [47] I find that the appellant has shown on the balance of probabilities that failure to treat and avoid the severe consequences of Izaya's collapse was a result of medical error by a failure to diagnose, monitor and treat him appropriately. I am satisfied that Dr Richardson properly associated the cause of Izaya's collapse with failure to recognise signs that could have been detected with the particular care that would have been reasonable for a baby of this age following surgery. The crisis occurred between 6.00 am and 9.00 am on 2 February 2003 but Dr Richardson inferred, from evidence of significant weight loss, that Izaya was dehydrated secondary to a poor intake for some time prior to his collapse. It follows that there would have been opportunities to recognise a need for treatment. The primary need was to ensure feeding and breathing had fully recovered before the infant was discharged from hospital. A post-operative plan would then have ensured that the parents should have been able to recognise any ongoing need for further medical examination in the days following surgery. [48] Finally, I find that the responsibility for a post-operative plan remained with the surgeon until he had taken reasonable steps to ensure that a plan was in place and that another medical professional had assumed responsibility for it. That did not happen and the surgeon remained responsible for a reasonable period of time after the baby was discharged. That is because there was a special relationship between the surgeon and a vulnerable patient, imposing a non-delegable duty of care. If Izaya had been post-operatively placed in the care of a paediatrician or other appropriately qualified doctor, then the surgeon's duty of care would have been discharged. However I consider that it could not have been discharged by putting the infant in the care of nursing staff without complete instruction in the post-operative care of an infant of two months. It has been submitted that there is nothing to suggest that Izaya's discharge breached any hospital protocol. In fact there is no evidence of the protocol at Timaru Hospital, but it is clear from the evidence that Izaya required paediatric care or paediatric advice to his parents. I am satisfied from the evidence that the risks to a two month old child following surgery could not otherwise be addressed appropriately. [49] For those reasons the appeal is allowed with the effect that the review decision is quashed and the appellant will have cover for the consequences of his ventilatory and circulatory collapse on 2 February 2003. The appellant will have costs of $3,000 and reasonable disbursements. Judge D A Ongley District Court Judge