In 1977, Dr Kerr published an unusual case series in the British Journal of Anaesthesia. As a specialist in the area of anaesthesia for middle ear surgery, he had been using the technique of the day, inducing deliberate hypotension with a mixture of volatile and ganglion-blocking agents. Prompted by a desire to present his surgical colleague with as bloodless a field as possible, he decided to probe the physiological limits of the technique, essentially by investigating how low he could go [1].

In his article he described a personal series of 700 patients treated between 1969 and 1974, in whom a combination of halothane, pentolinium and head-up tilt had been used to reduce systolic pressure to 50 mmHg or lower, generally for a period of 1–2 h. He demonstrated that the chance of achieving what he classified as satisfactory haemostasis was 92% when the systolic was controlled at or below the target level, but only 41% when systolic was higher than 50 mmHg. A considerable number of patients were taken to even lower levels, with 42 held at a systolic pressure below 40 mmHg and five below 30 mmHg. Around 10% of his patients were over 60 years old. Before starting to recruit patients for this published series, Kerr had completed 500 anaesthetics using the same technique.

Kerr concluded that ‘The arterial systolic pressure which gave the most satisfactory haemostasis was 30–45 mmHg. In a few patients operating conditions were satisfactory above this value and in a few bleeding occurred in spite of pressures in the low range’. With regard to adverse effects, he was able to say: ‘In spite of the arterial pressures being reduced to very low values in many instances, there was no mortality or morbidity which could be ascribed to the technique… All patients had been examined as outpatients after operation, sometimes at intervals of many years and in no case has any resulting mental disturbance been detected’.

Modern practitioners may well raise an eyebrow at the levels of blood pressure employed by Kerr. However, it should be remembered that induced hypotension was much more commonly used in the 70s and 80s, although primarily, in the argot of the day ‘…not to make the difficult easy, but to make the impossible possible’. In the next 10 months, two readers of the British Journal of Anaesthesia were sufficiently concerned to write to the journal (although one was more interested in Kerr’s failure to use ECG monitoring than in the degree of hypotension), but otherwise the profession was silent [2, 3]. It is likely that other anaesthetists, emboldened by Kerr’s results, started copying his techniques.

Two years after Kerr published his article, he administered his hypotensive anaesthetic to Mr Hepworth, a patient undergoing mastoid surgery. Hepworth’s systolic pressure was lowered to 40 mmHg, with marked hypotension sustained for one and a half hours, and he suffered a spinal infarct. A claim for negligence was duly brought against Kerr and, 18 years after the event, the parties appeared in the High Court before The Hon Mr Justice McKinnon [4].

Eminent experts, including one past and one future President of the Royal College of Anaesthetists, were instructed by both sides to provide opinion as to whether the care provided by Kerr had fallen below the level of ‘a practice accepted as proper by a responsible body of medical men’, the well-known ‘Bolam’ test for negligence [5]. The judge, having heard the experts’ views, concluded that 60 mmHg was widely regarded as the lowest acceptable level to which blood systolic blood pressure should be lowered as part of a deliberate hypotensive technique, and further found that Kerr had not followed up or evaluated his patients in any meaningful way for cerebral or spinal ischaemia in the postoperative period or later. In finding in favour of Hepworth, he stated: ‘As I find, the defendant adopted a new hypotensive anaesthetic technique which, as he knew, had never been attempted routinely before. Other anaesthetists had never gone to such low levels over such long periods. The defendant, as he accepted, was, to begin with at least, plainly experimenting. He expected serious complications such as cerebral or cardiac thrombosis to occur. He was surprised when they did not. He never, however, attempted to embark upon any proper scientific validation of his technique in some 1500 patients by the time of the plaintiff’s operation…I simply cannot, and do not, accept that the defendant was justified in doing what he did without proper scientific validation of his technique’.

The reader may well feel that Kerr was rather badly treated in this judgment. He had gone considerably further than many practitioners of his day, at a time when clinical audit was largely unknown, in collecting a very large case series, scrupulously recording his data, and then submitting his findings for consideration by his peers. Publication in a respectable peer-review journal would be regarded by scientists as confirmation of the validity of the technique, especially as there was no accompanying editorial comment and very little concern expressed in subsequent correspondence. However, McKinnon J was almost certainly accurate in his summing up and his finding in favour of the plaintiff; this was a technique flying in the face of conventional wisdom and, whereas such experimentation is permissable, it must be scrupulously validated (and of course – although this was not said at the time – patients need to be fully informed of what is intended so that they can decide whether they wish to participate).

In the case of Hepworth vs Kerr, it seems that science got it wrong and the law got it right. It would be fair to say that the practice of inducing hypotension of this degree was on the wane by the time the case came to court, but the judgment in Hepworth vs Kerr essentially stopped the practice, particularly the use of ganglion-blockers, in its tracks. Patient safety was certainly enhanced as a result of the ensuing publicity.

However, one swallow does not make a summer, and it is pertinent to ask whether the involvement of law in medicine makes patients safer. The two main legal tests upon which clinical negligence is determined are the Bolam principle (see above), and the Bolitho principle, which states that, before accepting a body of opinion as being ‘responsible, reasonable or respectable’, the Court will need to be satisfied that, ‘in forming their views, the experts have directed their minds to the question of comparative risks and benefits’ [6]. These two tests appear, on the face of it, to be designed to weed out the rogue practitioner on the one hand and to discourage practice that flies in the face of evidence-based medicine and good risk management on the other. Civil litigation should theoretically improve standards, but does it do so in practice?

In addressing this, I intend to consider three areas where law impacts upon medicine: the role of the Court as arbiter in matters of clinical practice; lessons learnt from analysis of negligence claims; and resource allocation.

Judges are traditionally not well-versed in science, often having entered the law via a liberal arts route. I once spent a fruitless hour in the High Court with a whiteboard and several coloured felt pens trying to explain the concept of moments of force in an attempt to justify the use of a semi-sitting position as an aid to alleviation of aorto-caval compression; most medical expert witnesses will have similar stories. Civil law works to a standard of proof of 50% (the balance of probabilities); scientists need to be at least 95% sure before accepting a hypothesis. Science is based on hard fact, derived from systematic observation; although judges take expert argument into account, the weight they place upon such evidence is theirs to determine, and they may be swayed, rightly or wrongly, by rhetoric and emotion. On balance, a court of law would not seem the right place in which to test scientific evidence, especially in a complex speciality such as anaesthesia, and so it often proves to be the case.

In another high-profile anaesthetic-related negligence case, two consecutive patients on an operating list, paralysed after spinal anaesthesia, lost their case against the anaesthetist when the Court concluded that the cinchocaine, the local anaesthetic used, had become contaminated with phenol used for sterilising the ampoules via microscopic cracks in the glass [7]. This was not a recognised phenomenon at the time of the events in question, 1947, and the patients, Wooley and Roe, lost their case. Hutter, in a detailed examination of the facts of the case, concluded that phenol, in the concentrations that would have resulted, could not have caused the neurological pathology suffered by the claimants [8]. It was his view that the damage arose from contamination by an acid descaler used in the water baths in which the needles and syringes were sterilised, an unarguably negligent act.

Not only did the Court almost certainly get it wrong when the Wooley and Roe case was heard in 1953, but the publicity arising from the press coverage [9], coupled no doubt with the insidious concept of contamination via invisible cracks, led to spinal anaesthesia, the technique of choice at the time for lower limb and inguinal surgery, being nearly abandoned across the UK for many years. The impact of this upon patient safety cannot have been anything other than malign, when the relative risks and benefits of general vs regional anaesthesia are considered.

The possibility of learning lessons to improve patient safety by analysing databases of negligence claims would seem, on the surface, to be of potential benefit to patients. The recent availability of data from the National Health Service Litigation Authority (NHSLA), the body responsible for defending NHS trusts, allows similar analyses to those carried out in the US and elsewhere on closed claims [10]. In practice, however, the value of these databases as a tool for improving patient safety is very limited. First, they only include cases, unsurprisingly, that have been the subject of a legal claim. This will only be a very small proportion of incidents causing the patient harm. Secondly, these databases are prepared by lawyers for lawyers, and those who have set themselves the task of analysing them have run into considerable problems in interpreting the data. As an example, lawyers tend to include pain during regional anaesthesia under the general heading ‘anaesthetic awareness’, with self-evident implications when it comes to analysing complications of obstetric anaesthesia [11]. Data collected by clinicians for clinicians are likely to be of much greater value, as has been shown by long-running audits such as the Confidential Enquiry into Maternal Deaths [12], and shorter, intensive national surveys such as those carried out by the Royal College of Anaesthetists into the complications of neuraxial blocks [13].

The main negative impact of negligence litigation on patient safety and quality of care must, however, come from the cost of claims and the process by which they are settled. In 2009–2010, the Clinical Negligence Scheme for Trusts, the scheme whereby the NHSLA indemnifies NHS bodies against clinical litigation, paid out £650 million in claims, a figure that has doubled since 2004–2005. Of this, £163 million was for legal costs, with 74% of this sum going on the claimant lawyers’ fees [14]. This money is very largely top-sliced from the budget available for healthcare, taking priority over all other clinical needs.

None of this takes into account the impact of so-called ‘defensive medicine’, which can be defined as those aspects of patient care that would not happen if not for fear of litigation. Do we over-investigate or, worse, over-treat our patients to defend our reputations, jobs and livelihoods from the perceived predation of the law, or does the spectre of legal action act as a driver to better and safer care? There is insufficient space to consider this question in depth here, but it may help to consider the specific area of documentation. Good records are an essential part of good care; they allow continuity between professionals, indicate the results of investigations and record how a patient responds to a particular treatment. But excessive records that do not advance care carry their own problems: they swell the documentation, obscuring important material and their maintenance can distract attention from the patient. Next time you have a patient’s record in front of you, try to weed out those papers that appear to have been created primarily for the purpose of protection against possible litigation – you may be surprised at how slim the file becomes suddenly.

Although patients in any civilised society must have recourse to legal redress when they suffer harm as a result of negligent treatment, and although sometimes a judge may provide a common-sense rebuff to poor science, negligence litigation probably does not benefit patient safety and may even, primarily by diverting resources, prevent progress in this field. Advances in patient safety come from the aforementioned audits, sometimes from bodies such as the National Patient Safety Agency, itself the offspring of a Department of Health enquiry rather than the litigation process [15], and occasionally from wise coronial comments made at an inquest. The spectre of civil litigation may have anaesthetists looking over their shoulders, but that is not necessarily the safest position when moving forward.

Competing interests

  1. Top of page
  2. Competing interests
  3. References

Dr Bogod receives legal instructions from claimants and defendants as a medicolegal expert in negligence litigation.


  1. Top of page
  2. Competing interests
  3. References
  • 1
    Kerr AR. Anaesthesia with profound hypotension for middle ear surgery. British Journal of Anaesthesia 1977; 49: 44752.
  • 2
    Donald JR. Profound hypotension for middle ear surgery. British Journal of Anaesthesia 1978; 50: 845.
  • 3
    Rollason WN. Anaesthesia with profound hypotension for middle ear surgery. British Journal of Anaesthesia 1978; 50: 2067.
  • 4
    Hepworth v Kerr [1995] 6 Med LR.
  • 5
    Bolam v Friern Hospital Management Committee [1957] 1 WLR 583.
  • 6
    Bolitho v City and Hackney Health Authority [1997] 4 All ER 771.
  • 7
    Roe v Ministry of Health and Others. Wooley v Same [1954] 2 All Eng LR 131-43.
  • 8
    Hutter CDD. The Wooley and Roe case: a reassessment. Anaesthesia 1990; 45: 85964.
  • 9
    Allegation of irritant in anaesthetic: damages claimed. The Times 1953; 21: 12.
  • 10
    Cook TM, Bland L, Mihai R, Scott S. Litigation related to anaesthesia: an analysis of claims against the NHS in England 1995–2007. Anaesthesia 2009; 64: 70618.
  • 11
    Szypula K, Ashpole KJ, Bogod DG, et al. Litigation related to regional anaesthesia: an analysis of claims against the NHS in England 1995–2007. Anaesthesia 2010; 65: 44352.
  • 12
    LewisG (ed). The Confidential Enquiry into Maternal and Child Health (CEMACH). Saving Mothers’ Lives: Reviewing Maternal Deaths to Make Motherhood Safer – 2003-2005. The Seventh Report on Confidential Enquiries into Maternal Deaths in the United Kingdom. London: CEMACH, 2007.
  • 13
    Royal College of Anaesthetists. NAP3. The Third National Audit Project of the Royal College of Anaesthetists. London: RCoA, 2009.
  • 14
    NHSLA. The National Health Service Litigation Authority: Reports and Accounts 2010. London: The Stationery Office, 2010.
  • 15
    Toft B. External Inquiry into the Adverse Incident that Occurred at Queen’s Medical Centre, Nottingham, 4th January 2001. London: Department of Health, 2001.