A University of Adelaide PhD student has just completed one of the world's first academic studies on nurses who deliberately kill their patients.
John Field , a senior academic, lawyer and registered nurse with more than 30 years' experience, has examined media reports and professional literature involving 48 cases from around the world where nurses have murdered patients.
The nurses - mostly serial killers - are believed to have murdered more than 750 patients using a variety of methods, although the number of murders of which they have been convicted is much lower due to a difficulty in obtaining hard evidence.
Mr Field's PhD looks at the conditions which make it possible for nurses to murder patients, often over a period of many years, without being detected.
"In one case in France, the nurse had murdered 30 patients before she was apprehended," Mr Field says.
Among the cases he examined was US serial killer Charles Cullen, a registered nurse in New Jersey who murdered between 40 and 80 patients over a 16-year period. He worked in 10 different health facilities during that time. In 2006 he was sentenced to 18 consecutive life sentences, with a non parole period of 397 years.
"The 1993 conviction of UK enrolled nurse Beverley Allitt for the murder of four babies and the attempted murder of nine others, followed by the conviction in 2000 of Dr Harold Shipman, a UK general practitioner, for the murder of 15 patients resulted in increased surveillance of health professionals in hospitals and health services in developed countries," Mr Field says.
"It has not eliminated murder by health professionals though - and that includes murder by nurses. This is shown by the convictions of English nurse Benjamin Geen, who was found guilty in 2006 of two murders and 15 attempted murders, and Colin Norris, a Scottish nurse who this year was convicted of four murders and one attempted murder."
Mr Field says that even though the proportion of nurses who murder patients is "miniscule", he wants to increase awareness of such incidents to help eliminate, or at least minimise, the risk of similar cases occurring in hospitals around the world.
"The murder of patients in health care facilities seems to be independent of the quality of care provided. My key conclusion is that the murder of a patient by a nurse could occur in any facility.
"Of the 48 cases included in my study, 38 were serial killers. While other nurses may have harboured suspicions about the murderer for a while, it took a long time for their suspicions to be reported. This points to a need for more open communication in our hospitals," he says.
Mr Field says hospital administrators have also been generally slow to react to reported suspicions. "The response on a number of occasions has been to encourage the nurse to move on, which just enables them to continue murdering patients in other facilities."
The PhD student says his study reveals a need for the nursing profession to acknowledge the possibility of murder in their own workplaces.
"While the overwhelming majority of nurses are outstanding professionals, there is a very small number who are capable of committing such heinous crimes. We need to encourage their peers to report their suspicions in the knowledge they will be dealt with fairly, correctly and sensitively, but with the patients' safety as the paramount consideration."
Of the 48 cases investigated, 26 came from the United States, six from the United Kingdom, and the rest from Austria (4), Germany (3), The Netherlands (2) and one each from Canada, Egypt, France, Hungary, Italy, Japan, South Africa and Switzerland.
"There have been some cases in Australia of nurses being charged with the murder of patients and at least one of these made it to court. None have been successfully prosecuted as there has always been too little evidence to sustain the prosecution," he says.
Mr Field is a Senior Lecturer in Nursing at James Cook University . He is based on Thursday Island and responsible for the undergraduate nursing program in the Torres Strait, where 90% of the students are Indigenous.
Mr Field is one of 110 students who will graduate from the University of Adelaide this Saturday 19 April at an offshore ceremony at the Ngee Ann-Adelaide Education Centre  in Singapore.
Mr Field's PhD thesis can be found online in the University of Adelaide's digital library, Adelaide Research and Scholarship, at: