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Case study: ‘Out by ten’ – Samuel McIntosh died after receiving 10 times the correct dose of a salt solution
(November 2010)
According to newspaper reports, four-month old Samuel McIntosh died in July 2009 after receiving 50mL of a salt solution, a dose which was 10 times the 5mL that should have been given. Following an investigation the coroner, Dr Nigel Chapman, recorded a narrative verdict and ruled that the death was ‘due to a ‘drug error’, but not gross negligence.’
The two nurses who delivered the medication, Sister Karen Thomas and staff nurse Louisa Swinburn, spoke at the inquest of having been distracted during the administration of the solution but that they had not been aware of any errors being made.
"Out by ten" errors are often explainable as a simple calculation error; these usually happen when someone miskeys a zero or decimal point during a calculation. Research done in test 'classroom' settings has indicated that drug calculation errors by nurses and nursing students are common (Kapborg, 1994), and while the solution to reducing errors in practice seems to focus on 'improving the calculation skills of nurses' it may be that in a busy clinical setting other factors may also be critical sources of error. It is also important to note that errors made in a classroom-type setting do not necessarily indicate someone's skills in a clinical one (Wright, 2010). Research by members of the CHI+MED team suggests it may also be possible to reduce the frequency of such errors being made by appropriate design of the number entry system. Many number entry systems do little to help operators avoid making such mistakes or to detect them when made (Thimbleby and Cairns, 2010).
In the case here the nurses were reportedly distracted while working, leading to the incorrect amount of solution being drawn up and delivered. Following the verdict at Nottingham Coroner’s Court the Medical Director for Nottingham University Hospitals NHS trust, Dr Stephen Fowlie, said "We have changed the way salt solutions are used and given to ensure that these mistakes aren’t repeated. We have new guidance to minimise the need for concentrated salt solution, changed the infusion prescription chart on the neonatal unit and introduced a ‘tabard system’ to ensure nurses are not interrupted when administering drugs.”
The use of a tabard is an example of resilient behaviour being used to reduce the risk of wrong medication (or wrong amounts of medication) being administered. The tabards have clearly marked phrases such as “DRUG ROUND IN PROGRESS, PLEASE DO NOT DISTURB” and can reduce interruptions. A small audit of tabard use, published in the August 2010 issue of Health Services Journal, found that the tabards were generally well received by nurses, other staff and patients, and while interruptions were reduced there were some practical issues regarding availability and fit of appropriate tabards. While such a strategy may not provide a simple fix in all situations it is one of many steps that can be taken, as part of a strategy to improve patient safety.
Ongoing research as part of the CHI+MED project is investigating many issues relevant to this case including strategies and device design to mitigate against the disruptive effect of interruptions and exploring how number entry systems can help prevent out by ten errors being made.
References
Kapborg ID (1994) Calculation and administration of drug dosage by Swedish nurses, student nurses and physicians International Journal for Quality in Healthcare 6 (4): 389-395.
Scott J, Williams D, Ingram J and Mackenzie F (2010) The effectiveness of drug round tabards in reducing incidence of medication errors Health Services Journal online.
Thimbleby H and Cairns P (2010) Reducing number entry errors: solving a widespread, serious problem Journal of the Royal Society: Interface online.
Wright K (2010) Do calculation errors by nurses cause medication errors in clinical practice? A literature review Nurse Education Today 30 (1): 85-97.
News articles
Narrative verdict on death of baby given ten times too much salt solution
This is Nottingham website
Wednesday, November 24, 2010, 14:36
http://www.thisisnottingham.co.uk/news/Baby-given-times-correct-dose-salt-solution-inquest-hears/article-2933343-detail/article.html
'Louisa is goin 2 treat herself 2 bottle wine!' Facebook boast of nurse allowed back to work after fatally giving baby ten times correct dose of salt
Daily Mail website
10:13 AM on 25th November 2010
http://www.dailymail.co.uk/news/article-1332758/Facebook-boast-nurse-fatally-giving-baby-10-times-correct-dose-salt.html
Nurse involved in baby's salt solution overdose death is under investigation
This is Nottingham website
Thursday, November 25, 2010, 09:02
http://www.thisisnottingham.co.uk/news/Baby-died-given-overdose-salt-solution-Nottingham-hospital/article-2936513-detail/article.html
Suspected salt death baby named
This is Nottingham website
Thursday, July 23, 2009, 20:03
http://www.thisisnottingham.co.uk/news/Suspected-salt-death-baby-named/article-1191735-detail/article.html
Case study: Jamie Merrett and Victoria Aylward – what role did the ventilator’s design play? (October 2010)
Tetraplegic Jamie Merrett’s quality of life has been permanently worsened after a carer, Victoria Aylward, mistakenly switched off the ventilator which was keeping him alive. He was without oxygen for 21 minutes while the carer, Victoria Aylward, and a colleague failed to get the ventilator restarted and struggled to provide emergency ventilation using a hand held ventilation bag. You can read more about the case at Channel 4 News and The Telegraph.
Although the nurse and the nursing agency are taking the blame in this tragic case there are still questions to be asked about the ventilator and how a better design would have reduced the risk of such an incident, or helped the carers to recover from it more quickly. Professor Harold Thimbleby of CHI+MED (a large research project on Human-Computer Interaction in Medicine) said,
“We don’t know why it was so easy for the ventilator to be switched off and what role the design of the machine could have played here. There should have been interlocks or checks, and the ventilator should have been harder to switch off, and certainly easier to switch back on again. Even if unplugged the device would have had battery back up to maintain power to such a vital piece of equipment. It’s designed to keep people alive and well-ventilated; it failed."
We do not know if these pertinent questions were taken into consideration in the Care Quality Commission's confidential report, which has apparently been leaked to the BBC, but we believe that answers to these questions are essential to get a fuller picture of the incident and to improve care everywhere.
A video shows the nurse pressing a button and the ventilator beeping as it is switched off. An interlock would have meant lifting a flap or similar, and more deliberately switching the device off. The device didn’t ask the user to confirm the switch off – when is there ever such a rush to switch off a working ventilator that an extra step would be problematic? A better approach may have been to require the air tubes to be physically removed first, so the ventilator ‘knows’ it isn’t keeping somebody alive, then it will switch off.
Another issue is that the carers appear to have had tunnel vision after the ventilator was switched off. Rather than switching it back on, they persevered in manual resuscitation that they appeared not to have much skill in doing (one wonders why). Training in the needs of specific patients, and more generally training in human factors would evidently help everybody, from designers to nurses.
The entire system appears to have flaws, from design, through to training, and compounded by the failure to listen to and act on patient’s worries. On the positive side, it is interesting to see how technology, in this case the video camera, can draw attention to improvements in healthcare.
The worst part of the story is the saddest: the patient was aware of the potential problem, which is why a video camera had been set up. There was clearly poor communication and teamwork in his care: this is what inexorably led to the incident, not the actions of the people at the last stages of the problem who we see in the video. Indeed, anybody there who pressed the button could have caused the same result – it is clearly therefore not any carer’s or carers’ fault at the time the incident occurred.
NB We would be happy to work with any people more closely involved in this case to work towards improving outcomes; it is awkward to speculate with only the video and media reports to go on.