Graham, Duncan --- "Causation problems in medical negligence cases - Part 1" [2020] PrecedentAULA 17; (2020) 157 Precedent 20

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CAUSATION PROBLEMS IN MEDICAL NEGLIGENCE CASES

By Dr Duncan Graham SC

Causation problems are not peculiar to medical negligence cases. They are, however, magnified by the factual and scientific controversies that such cases commonly generate. There are a number of thorny issues that may arise. In this two-part article, I will address those related to hypothetical causation (Part 1) and those arising from the use of epidemiology (Part 2).

PART 1: HYPOTHETICAL CAUSATION PROBLEMS

What I term hypothetical causation is often described as the counterfactual analysis, or even ‘the counterfactual’. It arises once a breach of duty has been proved or admitted. The analysis ignores events that have happened, and instead looks at what would have transpired had reasonable care been exercised by a defendant. It is a fertile area for a defendant to explore because a defendant will not be causally liable or legally responsible for an injury if he or she adduces evidence that no alternative course of action would have eliminated or reduced the risk of injury.^[1]

ASSESSING HYPOTHETICAL CAUSATION

The process of assessing hypothetical causation was described by Hayne J (dissenting on the facts) in Chappel v Hart:

‘The search for causal connection between damage and negligent act or omission requires consideration of the events that have happened and what would have happened if there had been no negligent act or omission. It is only by comparing these two sets of facts (one actual and one hypothetical) that the influence or effect of the negligent act or omission can be judged.’^[2]

The process was reiterated by the High Court in Tabet v Gett^[3] by Hayne and Bell JJ:

‘For the purposes of the law of negligence, “damage” refers to some difference to the plaintiff. The difference must be detrimental. What must be demonstrated (in the sense that the tribunal of fact must be persuaded that it is more probable than not) is that a difference has been brought about and that the defendant’s negligence was a cause of that difference. The comparison invoked by reference to “difference” is between the relevant state of affairs as they existed after the negligent act or omission, and the state of affairs that would have existed had the negligent act or omission not occurred.’^[4]

And by Keifel J:

‘The issue whether damage has been caused by a negligent act invites a comparison between a plaintiff’s present position and what would have been the position in the absence of the defendant’s negligence. Such an inquiry directs attention to all the circumstances pertaining to the plaintiff’s condition at the time he or she sought the medical treatment which was not properly provided. The question of whether harm or damage has been suffered is bound up in the question of causation.’^[5] [footnotes omitted.]

The four most important reasons why medical negligence cases pose special difficulties for hypothetical causation are:

1. Patients usually present to doctors with a condition that requires treatment.

2. There is often more than one treatment alternative available for a particular condition.

3. Treatment may involve referrals to or treatment by a number of specialists before a condition is cured.

4. Whether alternative treatment would have avoided an injury may depend on epidemiological evidence.

The effect of all of these circumstances may need to be evaluated as part of a counterfactual analysis. For example, in a case involving a delay in diagnosing breast cancer, it may be necessary to evaluate the clinical course of the disease at an earlier point in time; what the outcome would have been with a lumpectomy compared with radiation; what a surgeon, radiation oncologist and medical oncologist would each have advised; and what survival could have been expected from epidemiological studies if the diagnosis had been made at the appropriate time.

FAILURE TO WARN CASES

Hypothetical causation presents the most obvious challenges for a plaintiff in a so-called ‘failure to warn’ case. What would have happened if, prior to consenting to medical treatment, the plaintiff had been warned of the risk of injury that he or she in fact suffered as a result of undergoing that treatment? Given the economical way in which many doctors record consultations, there is often a reasonable basis for believing a plaintiff was not informed of a particular risk – there is simply no note of the risk warning. From that point on, things become tricky; there are a number of roadblocks for a plaintiff in proving that he or she would not have proceeded with the treatment if warned of the risk of injury that eventuated.

The paradigm case is Wallace v Ramsay Health Care Ltd.^[6] At first instance, the trial judge found that the plaintiff would have consented to the operation even if warned of the risk of paraplegia (which was not the injury that materialised). It is worth setting out the prevailing state of affairs at the time surgery was contemplated to see why the plaintiff failed to prove that he would not have consented to surgery if warned of all risks:

‘As the result of his preoperative condition, as described by him, the plaintiff was desperate for some form of pain relief. He had attended a pain management centre in an effort to try to reduce the pain in his back and legs ... He had tried physiotherapy but this had not helped. He was taking more and more medication with no corresponding benefit ... He told Dr New that the fact of the matter was that he was not getting any better. He felt inadequate and useless. He had severe restrictions in movement. This was a cause of significant stress and anxiety. He had bouts of depression because his future was uncertain. He approached Dr Kam for assistance to try to do something about unremitting pain, because he could barely move. Dr Diwan had told him that surgery might be risky. He agreed Dr Kam had told him the same thing. By the time he saw Dr Kam for the second time “he was desperate for relief” ... The last resort was to undergo surgery.’^[7]

The fact that the High Court dealt with a different issue on appeal does not undermine the basic fact that the plaintiff had no real option but to undergo the operation, even if he was warned of all relevant risks.

There are other problems with the counterfactual analysis in failure to warn cases. First, it is doubtful whether a court will accept subjective, circumstantial evidence of a plaintiff, given with the benefit of hindsight, that suggests the plaintiff would not have consented to the procedure if he or she had been given appropriate warnings of the risk that occurred and its consequences. Secondly, evidence of what an injured plaintiff would have done if warned of a risk of injury is often inadmissible.^[8] Thirdly, even if such evidence, or other subjective, circumstantial evidence, is admissible, it would be viewed with great scepticism by a court.^[9]

For all of these reasons, failure to warn cases are in my opinion cases for the despairing, when no other causes of action appear to have merit. As we shall find, however, hypothetical causation can be equally perilous for other types of medical negligence cases. Proof requires a degree of lateral thinking and planning.

PROOF OF HYPOTHETICAL CAUSATION

The proper approach to proof of hypothetical causation demands consideration of the key decision in Bolitho v City and Hackney Health Authority.^[10] In that case, a two-year-old boy suffered respiratory failure, cardiac arrest and brain damage while in hospital. He had suffered two earlier warning episodes. The trial judge found that the defendant was in breach of its duty of care to the plaintiff because the senior paediatric registrar did not attend to the patient or arrange a suitable deputy to do so after receiving two telephone calls from nursing staff well before the final catastrophic episode. One of the questions before the House of Lords related to causation: would the cardiac arrest and brain damage have been avoided if the paediatric registrar or another doctor had attended the patient after the first two calls? It was common ground that the cardiac arrest would have been avoided only if the patient was intubated before the final catastrophic episode. Thus, the question was whether the registrar (Dr Horn) or a suitable deputy (Dr Rodger) would have intubated the plaintiff if they had fulfilled the defendant’s duty of care by attending him after the nurses’ calls.

The proper approach to the question of hypothetical causation is set out in the decision of Lord Browne-Wilkinson. It is important in my view to set out the critical passage in full:

‘Where, as in the present case, a breach of a duty of care is proved or admitted, the burden still lies on the plaintiff to prove that such breach caused the injury suffered. In all cases the primary question is one of fact: did the wrongful act cause the injury? But in cases where the breach of duty consists of an omission to do an act which ought to be done (eg the failure by a doctor to attend) that factual inquiry is, by definition, in the realms of hypothesis. The question is what would have happened if an event which by definition did not occur had occurred ... Therefore in the present case, the first relevant question is “What would Dr Horn or Dr Rodger have done if they had attended?” As to Dr Horn, the judge accepted her evidence that she would not have intubated. By inference, although not expressly, the judge must have accepted that Dr Rodger also would not have intubated: as a senior house officer she would not have intubated without the approval of her senior registrar, Dr Horn ...

However, in the present case the answer to the question “What would have happened?” is not determinative of the issue of causation. At the trial the defendants accepted that if the professional standard of care required any doctor who attended to intubate Patrick, Patrick’s claim must succeed. Dr Horn could not escape liability by proving that she would have failed to take the course which any competent doctor would have adopted. A defendant cannot escape liability by saying that the damage would have occurred in any event because he would have committed some other breach of duty thereafter. ... I adopt the analysis of Hobhouse LJ in Joyce v Merton, Sutton and Wandsworth Health Authority [1996] 7 Med L R 1. In commenting on the decision of the Court of Appeal in the present case, he said, at p20:

“Thus a plaintiff can discharge the burden of proof on causation by satisfying the court either that the relevant person would in fact have taken the requisite action (although she would not have been at fault if she had not) or that the proper discharge of the relevant person’s duty towards the plaintiff required that she take that action. The former alternative calls for no explanation since it is simply the factual proof of the causative effect of the original fault. The latter is slightly more sophisticated: it involves the factual situation that the original fault did not itself cause the injury but that this was because there would have been some further fault on the part of the defendants; the plaintiff proves his case by proving that his injuries would have been avoided if proper care had continued to be taken. In the Bolitho case the plaintiff had to prove that the continuing exercise of proper care would have resulted in his being intubated.”’ [emphasis added].^[11]

In considering whether the defendant could escape liability for negligence simply by calling evidence from a number of responsible medical experts who supported its view about the need for intubation, the House of Lords held that the trial judge must be satisfied that the defendant’s ‘experts have directed their minds to the question of comparative risks and benefits and have reached a defensible conclusion on the matter’.^[12] The House of Lords considered that the defendant’s expert evidence was not unreasonable, irresponsible or respectable, and the plaintiff’s claim therefore failed.

The House of Lords’ approach to the question of causation in Bolitho is consistent with the approach to hypothetical causation in Australia, although it has not yet been fully considered by a superior court.^[13] It makes it important for a plaintiff lawyer to ascertain what the actual treating doctor in question would have done but for his or her (or a hospital’s) breach of duty and also objectively what a reasonable doctor in the circumstances would have done. The second question will require expert opinion to answer.

The Bolam test,^[14] however, does not apply in Australia.^[15] Section 5O of the Civil Liability Act 2002 (NSW) and corresponding provisions in the other states and territories introduced a modified Bolam test.^[16] Such a peer professional practice defence is not part of the law of causation. Nonetheless, consistent with Bolitho, a court needs to carefully assess any expert opinions about the hypothetical conduct of a third-party doctor.

This raises questions about how this peer professional practice defence operates when a court is considering the counterfactual. There could be a trial within a trial about whether some hypothetical conduct would have been negligent or not. This will be difficult given the current uncertainty about how to construe the peer professional practice provisions.^[17]

ILLUSTRATING THE DIFFICULTIES – A CASE EXAMPLE

The difficulties confronting a plaintiff who is attempting to establish hypothetical causation were graphically highlighted in Varipatis v Almario.^[18]

In that case, the plaintiff suffered from morbid obesity. He had tried to lose weight by medical measures and failed. The obesity resulted in the development of fatty liver disease and then non-alcoholic steatohepatitis (NASH), which led to cirrhosis and liver failure. The cirrhosis in turn caused liver cancer. By the time the case came to trial, the plaintiff’s life expectancy was greatly reduced. The only treatment that could have avoided this outcome was bariatric surgery (lap band surgery). Thus, the plaintiff needed to prove that he should have been referred to a bariatric surgeon before he developed cirrhosis.

The critical case against the defendant (his general practitioner) was that he should have referred the plaintiff to a hepatologist (a liver specialist) because his liver function tests were increasingly abnormal over time and warranted specialist attention. At first instance, the plaintiff succeeded because the trial judge found that the defendant should have referred him to a bariatric surgeon. This was overturned on appeal on the basis that the general practitioner’s evidence that was relied upon by the trial judge was unsatisfactory. I wish to focus on the failure to refer to a hepatologist.

The trial judge found that the defendant breached his duty of care to the plaintiff by not referring him to a hepatologist by September 2000 at the latest. In addition, he found that, had the plaintiff been referred to a bariatric surgeon, he would have been offered and undergone surgery and would have avoided his injuries (cirrhosis, liver failure and liver cancer). These findings were either not challenged on appeal or not disturbed or considered by the NSW Court of Appeal.

The missing link, however, in the chain of causation was whether a hepatologist would and should have referred the plaintiff to a bariatric surgeon. It was contended that, if the plaintiff had been referred to a hepatologist, he would then have been on-referred to a bariatric surgeon for consideration of bariatric surgery. He would then have been offered the surgery and undergone it, thereby avoiding his terminal injuries. The NSW Court of Appeal rejected these arguments.

Three hepatologists gave evidence. The Court was confronted with a divergence of expert opinion in relation to hypothetical causation. It was necessary for the Court to weigh the evidence itself and decide what a reasonable hepatologist would and should have done in the particular circumstances.

The hepatologists called by the defendant gave evidence that it was not standard practice in 2002 to refer a morbidly obese patient to a bariatric surgeon. The expert evidence of the plaintiff was that, by the time of his hypothetical referral to a hepatologist, the plaintiff would have been at most 56 years of age. He would have been suffering from life-threatening morbid obesity, with serious co-morbidities and deteriorating liver function. He was at a not insignificant risk of developing cirrhosis, liver failure and liver cancer. All prior attempts at conservative or medical treatment for his morbid obesity had failed. The only remaining untried form of treatment was bariatric surgery. The plaintiff contended that there was only one practical treatment option: an ordinary, skilled hepatologist would and should have referred the plaintiff to a bariatric surgeon by September 2000 at the latest.

Justice Basten rejected the plaintiff’s contention for two principal reasons. First, he found (or considered the trial judge to have found) that hepatologists would not have been particularly concerned about the plaintiff’s obesity.^[19] Secondly, he found that it was ‘by no means clear that the hepatologists would have referred to a bariatric surgeon in 1997–2000’.^[20]

The bottom line is that hypothetical causation was just too hard to prove. In order to succeed, the plaintiff had to prove:

(a) A reasonable hepatologist would have known about the connection between obesity and liver disease, including cirrhosis, by 2000;

(b) A reasonable hepatologist would have known about the connection between cirrhosis and liver cancer by 2000;

(c) A reasonable hepatologist would have considered that bariatric surgery was a reasonable treatment alternative for morbid obesity and liver disease in 2000;

(d) The plaintiff did not have cirrhosis by September 2000;

(e) A reasonable hepatologist would have referred the plaintiff to a bariatric surgeon before he developed cirrhosis;

(f) A bariatric surgeon would have offered surgery to the plaintiff;

(g) The plaintiff would have been able to afford the surgery (it could only be performed privately at the time);

(h) The plaintiff would have consented to the surgery; and

(i) The cirrhosis, liver failure and liver cancer would have been avoided.

The plaintiff effectively proved everything but (e). He ticked all but one box and consequently lost.

SOME IMPORTANT LESSONS

An important lesson to be learned from Almario is that hypothetical causation should always be assessed before proceedings are launched. It should then be reviewed once the litigation has commenced. An assessment of hypothetical causation is likely to require the input from experts and lay witnesses. Do not accept that proof of breach of duty will be enough for the case to settle. Certainly, do not accept that proof of injury following treatment will be enough to prove causation. Finally, if it is necessary to prove a chain of events as part of the counterfactual assessment, be careful about prosecuting a case where there are too many links in the chain to prove. Such cases are intimidating for both lawyers and the court.

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^[1] Chappel v Hart (1998) 195 CLR 232, 246–248.

^[2] Ibid, 282 [113].

^[3] [2010] HCA 12; 240 CLR 537.

^[4] Ibid, [66].

^[5] Ibid, [140].

^[6] [2010] NSWSC 518.

^[7] Ibid, [92].

^[8] See eg, Civil Liability Act 2002 (NSW), s5D(3)(b).

^[9] See eg, Seltsam Pty Ltd v McNeill [2006] NSWCA 158, [123] per Bryson JA; Elbourne v Gibbs [2006] NSWCA 127, [67] per Basten JA.

^[10] [1997] UKHL 46; [1998] AC 232.

^[11] Ibid, 239F–240G.

^[12] Ibid, 242A-B per Lord Browne-Wilkinson; see also 243B-E.

^[13] It was considered by Kirby J in Finch v Rogers [2004] NSWSC 39 (he agreed that it was similar to the approach in Chappel v Hart). It was also referred to by the Court of Appeal in South Eastern Sydney Area Health Service v King [2006] NSWCA 2. That decision was consistent with the first limb of Bolitho. The Court decided that it was unnecessary to consider whether both limbs of the Bolitho test applied in Australia.

^[14] Bolam v Friern Hospital Management Committee [1957] 1 WLR 583, 587.

^[15] Rogers v Whitaker [1992] HCA 58; (1992) 175 CLR 479.

^[16] Dobler v Halverson (207) [2007] NSWCA 335; 70 NSWLR 151, 168 [62] per Giles JA.

^[17] See for example, Sparks & Gray v Hobson [2018] NSWCA 29; Child and Adolescent Health Service v Mabior [2019] WASCA 151.

^[18] [2013] NSWCA 76.

^[19] Ibid, [77].

^[20] Ibid, [78].