A widespread misunderstanding exists regarding the scientific investigative and research skills of medical doctors compared with scientists. Many assume that medical doctors, with their hands-on patient experience, possess a robust foundation in the principles of scientific research and investigation. However, this is often not the case. Their training primarily equips them to diagnose, treat, and manage patient health, with the foundational emphasis on clinical practice over research or investigative methodology.
The media landscape, and the diminished understanding of the field of life sciences further perpetuates this misconception. This has been observed in numerous health epidemics, whether it be due to the causes of common diseases or even reasoning about health related outcomes. Clinicians, because of their frontline involvement in patient care, often become the go-to commentators in media circles. Their insights into patient symptoms, care strategies, and disease management are undoubtedly valuable. Yet, when the media presents them as broad scientific experts or specialists outside their clinical domain, it can lead to potential misinformation. The audience might misinterpret their words, thinking their clinical expertise equates to a deep understanding of the nuances found in the complex body of scientific research surrounding human health and disease.
Labeling all medics as experts simply because they practice in a specific branch of medicine is a gross over simplification of the purposes behind the creation of medical specialisms. Many clinicians have not undergone training in areas such as research methodology, investigative approaches or scientific literature appraisal. When they lack these tools, they might not be equipped to critically evaluate the quality or implications of the complex phenomena they are tasked with investigating. This becomes even more concerning when such clinicians are presented as scientific authorities, in a court of law, and their testimony is relied upon to explain the scientific data and findings associated with a cluster of deaths in a neonatal unit.
The Translational Scientist
Over the last 15 years, research in the life sciences has shifted considerably, and there is greater emphasis on linking research findings to specific physiological outcomes. This new approach to research science is called translational science and it is often referred to within the biomedical context as "translational medicine" or "translational research," which describes a discipline focused on bridging the gaps between basic scientific discoveries and their application in real-world clinical settings to improve human health. The goal of a translational scientist is to translate findings from laboratory-based research into methods, tools, and treatments that can help patients more effectively and rapidly. This process involves multiple steps, each ensuring that scientific discoveries are transformed into practical applications in a systematic and efficient manner.
A translational scientist is a professional who operates at the interface of basic science and clinical medicine. Their primary aim is to expedite the movement of discoveries from the laboratory to clinical settings to improve patient care and outcomes. They focus on "translating" or "bridging" the knowledge gained from basic scientific research into practical therapies, tools, and procedures that can be used to diagnose, treat, and prevent diseases. Translational scientists are well placed to conduct complex investigations such as the cause of a cluster of deaths owing to their strong background in both basic science and clinical medicine, allowing them to understand and navigate both realms effectively.
Conversely, medical doctors, are educated primarily in diagnosing, treating, and managing patient health. Although they certainly learn from existing research, their main emphasis lies in practical clinical care rather than in conducting research. This distinction leads to a common misconception that just because clinicians are well-versed in the results of scientific studies (like best treatment methods) this means they are also experts in the intricate methodologies of scientific investigations. Simply understanding the findings of a study does not grant one the expertise to design such studies, analyze the data, or interpret results in a broader scientific framework.
Figure 1, depicts the core differences between doctors and scientists and provides clues as to why a medical doctor may be ill-suited to carrying out complex scientific investigations, especially with regard a cluster of deaths. A scientist has typically received extensive training in a specific field of study, which often involves designing, conducting, analyzing, and interpreting research. This training emphasizes creating new knowledge or expanding on existing knowledge.
Rare Diseases: A Challenge to Medics
A perfect example of the difficulties that medics face in identifying the correct cause of patient symptoms can be found in the sphere of rare diseases. Rare diseases by definition, are those which have an incidence of less than 1 in 2000, however there are numerous rare diseases that have an incidence as low as 1 in 1, 000,000. The Rare Disease Impact Report consisted of a survey of patients and caregivers in the USA and UK who were impacted by rare diseases. The survey revealed that it took on average 7·6 years in the USA and 5·6 years in the UK to get an accurate diagnosis, during which time patients typically visited eight different physicians (four primary care and four specialist) and received two to three misdiagnoses (Shire, 2013).
A particular challenge in the detection of rare diseases is the influence of cognitive Biases. Doctors, like all humans, are prone to cognitive biases, such as the availability heuristic, which makes them judge the likelihood of diseases based on how readily examples come to mind. This causes medical doctors to disregard key symptoms observed in the patient and focus on those symptoms that are recognizable to the doctor (Li et al., 2020). In simple terms, the availability heuristic results in the overestimation of how rare the individual, object, or event is, which undermines the medic’s ability to accurately detect cause and effect when it comes to evaluating patient symptoms and how they relate to a given disease.
Rare Events get the Rare Disease treatment
In the trial of Lucy Letby, the primary expert witnesses, Dr Sandra Bohin and Dr David (Dewi) Evans, revealed the risk inherent in permitting medical doctors to carry out complex scientific investigations, into the deaths and decompensations of multiple premature or critically ill babies on an NNU. In conducting this investigation both medics demonstrated a complete abandonment of the principles of independent investigation, and from the outset sought to define the events they were investigating as opposed to collect evidence on the events.
“On reviewing the notes it became obvious for some of these cases what had happened, so although it was not obvious to other people, it was very clear to me and also to Dr Evans that some sort of foul play or some sort of unnatural act had befallen these children.”
Dr Sandra Bohin, 22nd August 2023
The statement from Dr Bohin exhibits confirmation bias, which is the tendency for individuals to search for, interpret, or remember information in a way that confirms their preconceptions. Dr Bohin’s assertion that upon review, it became "obvious" what had transpired in some of the cases suggests that she may have harboured a preconceived notion or theory about the cause of death and then looked for evidence in the notes that confirmed this belief. Scientifically, the approach should be more objective; instead of having an expectation and then searching for data that aligns with this, one should evaluate all the available data and then formulate a hypothesis or conclusion based on the data drawn from the population under study.
In addition to confirmation bias there is a tone of overconfidence bias in Dr Bohin’s statement that while the nature of the deaths was not "obvious to other people," it was "very clear" to the doctor, herself, and Dr. Evans. By suggesting that only they could see what others could not, Dr Bohin reveals a tendency to overvalue her opinion and overlook that such excessive confidence will skew her ability to evaluate confounding findings or variables. A scientific approach would necessitate the doctor blind herself in some manner, such that she were unable to determine whether she had evaluated the case previously. Further, her analysis should be cross-referenced with peer-reviewed studies, and a thorough assessment of similar clusters of neonatal deaths should have been undertaken.
Dr Bohin appears to be leveraging Dr. Evans' authority to bolster the credibility of her claim that there was foul play involved. In a scientific context, the consensus or agreement of one or even several experts is wholly insufficient. Objective evidence, replicated findings, and a broader consensus in the scientific community are crucial for validating conclusions. This most basic of approaches is the cornerstone of every investigation of a scientific nature, which require that there is a commitment to adhering to the scientific method.
“The Scientific method refers to the body of techniques for investigating phenomena, acquiring new knowledge, or correcting and integrating previous knowledge. It is based on gathering observable, empirical and measurable evidence subject to specific principles of reasoning.” (Newton, 1726/1999, pp 794-796)
Dr Bohin is not alone in the unique investigative approach she adopted. Dr Evans’ methodology falls under the same category of risk for several cognitive biases, which likely went some way to skewing his judgments and conclusions surrounding the cause of death and collapse in the neonates. When analysing a complex cluster of events it is necessary to first identify how to categorise each neonate in the cluster. That is to say, are the events due to one event, or multiple events, and what is the process for identifying the events? Essentially, a translational scientist would approach the cluster of events in the NNU with critical thinking, aiming to ensure that decisions and conclusions are rooted in solid evidence rather than their own perceptions or cognitive distortions.
Making incorrect assumptions
Dr Evans’ approach to conducting an investigation in to the neonatal deaths and collapses at CoCH was deeply flawed, and this was apparently made clear by Dr Evans‘ own reporting. In a recent podcast interview, Dr Evans confirmed that he did not carry out an objective, controlled investigation. Instead he described how he thumbed through a handful of reports before arbitrarily investigating one specific case file. Dr Evans then goes on to describe his reaction to reading the clinical notes as follows:
“I found something that shouldn’t be there, one of the medics had written down that, what he noticed what he thought was bruising over the area of the liver. That doesn’t happen, and I got the postmortem results, as well, and saw some pretty florid horrid photographs that showed several blood, areas of bleeding over the liver. In other words, trauma to the liver, and I thought oh my God this is dreadful. This is inflicted injury. So right from the beginning I said, look, this is inflicted injury, we need to investigate this.”
Dr Dewi Evans, September 5th 2023
The scientific approach to reviewing clinical notes would require that the scientist take a deliberate, methodical process, ensuring that all potential biases are recognized and controlled for, guaranteeing that conclusions are based on comprehensive evidence and analysis. Dr Evans disregards such an approach. Conversely, Dr Evans, jumps to a conclusion based on initial findings without considering all potential explanations. Although trauma to the liver may be indicative of inflicted injury, there are many other causes of liver damage, and it is essential to explore all plausible causes for such trauma before drawing definitive conclusions.
It is entirely likely that Dr Evans was actually misdiagnosing a rare condition named subcapsular liver hematoma (SLH). SLH is often associated with a high degree of mortality, and it is typically identified on autopsy especially, where it occurs in premature neonates with a very low birth weight. The condition is described by a blood clot in the liver, which may initially present with systemic and non-specific symptoms, and is often associated with sepsis (Ahn et al., 2010; Gonçalves C, et al., 2013; Liakou et al., 2022).
In the preterm neonate, the presentation of SLH might be subtle and is often overlooked. However, the medical dangers increase dramatically once the haematoma (a localized swelling filled with blood) ruptures through the liver's capsule, causing blood to enter the peritoneal cavity, which is the space within the abdomen that houses various organs. The sudden entrance of blood into this cavity can lead to an acute circulatory collapse, a life-threatening condition characterized by a dramatic drop in blood pressure and inadequate blood flow to vital organs. This can lead to organ failure and may be fatal if not addressed promptly (Ahn et al., 2010).
The clinical signs, such as a distended and rigid abdomen, further confirm the seriousness of the situation. When the abdomen becomes distended, it indicates the accumulation of blood or other fluids in the peritoneal cavity. The rigidity, on the other hand, points towards irritation of the peritoneum, likely due to the presence of blood. Dullness on percussion further supports the presence of fluid accumulation (Liakou et al., 2022).
Additionally, the presence of a bluish colouration of the overlying skin could suggest cyanosis, which can be due to the decreased oxygenation of the tissues, another sign of reduced circulation or compromised oxygen delivery to the tissues. It is entirely likely the bluish bruise that Dr Evans reported was actually the result of shifts in oxygenation in the periphery, which occurred due to circulatory collapse. What Dr Evans perceived to be intentional infliction of harm was more than likely a burst liver hematoma, and the consequent circulatory collapse.(Gonçalves C, et al., 2013).
The purpose of expert witnesses
As made clear in the Criminal Practice Directions for expert witnesses, it is known that there is an overriding duty for an expert witness to provide the court with a neutral, independent and unbiased opinion on matters within their expertise. Their duty is to the court and not to the party instructing or paying them. In the post-conviction interview, with the TV channel, ITV, Dr Bohin stated:
“And it wasn’t our role to say who had done that; it was our role to say something unusual had happened and what we thought had happened.”
Dr Sandra Bohin (August 22nd 2023)
Dr Bohin’s statement does convey a distinction between the responsibilities of diagnosing or identifying medical conditions and assigning blame. However, the phrasing she uses introduces elements of uncertainty and ambiguity, which cause one to doubt the reliability of her claims. Precision in language and evidence-based conclusions are essential, especially in contexts where such findings can have significant legal implications.
Dr Evans, and Dr Bohin, reveal something very important about medicine, and that is that holding a license to practice medicine does not transform a person into a individual bestowed with the ability to comprehend complex biological phenomena, coherently recognise antecedents of physiological states and effectively carry out differential diagnoses.
Ironically, Dr Evans’ hamfisted forensic investigation demonstrates how unlikely it was that anyone had the vaguest of ideas what was happening in the NNU either at the time of the events or in the period of the investigation. The clinical notes reviewed by Dr Evans and Dr Bohin appear to describe circulatory collapse, haemorrhage, hypovolemic shock, and cardiac arrest as sudden events not because they are sudden but because the clinical notes are such that they fail to describe the events coherently. This means that the medics are not properly monitoring the infants during the day shift, resulting in a failure to spot the antecedents of sudden collapse.
Lost in Translation
The emergence of translational scientists has resulted in a number of scientists being ideally suited to carry out complex disease investigations in distinct populations. A translational scientist would have used their combination of a deep understanding of both basic science and clinical medicine, paired with a research-oriented, problem-solving, and collaborative mindset, to effectively and appropriately conduct an investigation into the cluster of events that happened in the NNU at CoCH in June 2015- 2016.
In reality, the investigation, which was performed by Dr Evans and Dr Bohin, fell short of what was required in order to limit cognitive bias. Humans naturally tend to fit events into a narrative, whether that narrative is true or not. The doctor's assertion about "foul play" or an "unnatural act" seems to suggest a storyline. While this might or might not be accurate, relying on a narrative without sufficient evidence can be misleading. A scientific approach would involve disaggregating the data, analyzing each death independently, and not trying to fit them into a pre-existing narrative without substantial evidence.
A more effective approach to analysing the the cluster of deaths and collapses at CoCH, is set out in Figure 2.
Ahn HS, Chang YW, Lee DW, Kwon KH, Yang SB. An incidentally detected hepatic subcapsular hematoma in a very low birth weight newborn: a case report. Cases J. 2010 Jan 20;3(1):32. doi: 10.1186/1757-1626-3-32.
Gonçalves C, Aguilar S, Prior AR, Oliveira G. Hepatic subcapsular haematoma in a premature newborn. BMJ Case Rep. 2013 Jun 3;2013:bcr2013009074. doi: 10.1136/bcr-2013-009074.
Liakou P, Batsiou A, Konstantinidi A, Theodoraki M, Taliaka Kopanou P, Tavoulari EF, Tsantes AG, Piovani D, Bonovas S, Tsantes AE, Iacovidou N, Sokou R. Subcapsular Liver Hematoma-A Life-Threatening Condition in Preterm Neonates-A Case Series and Systematic Review of the Literature. J Clin Med. 2022 Sep 26;11(19):5684. doi: 10.3390/jcm11195684.
Li P, Cheng ZY, Liu GL. Availability Bias Causes Misdiagnoses by Physicians: Direct Evidence from a Randomized Controlled Trial. Intern Med. 2020 Dec 15;59(24):3141-3146. doi: 10.2169/internalmedicine.4664-20. Epub 2020 Aug 12. PMID: 32788532; PMCID: PMC7807127.
Shire, Rare Disease Impact Report https://globalgenes.org/wp-content/uploads/2013/04/ShireReport-1.pdf Accessed 20th September 2023