Elsevier

Applied Ergonomics

Volume 37, Issue 5, September 2006, Pages 669-679
Applied Ergonomics

Applying hierarchical task analysis to medication administration errors

https://doi.org/10.1016/j.apergo.2005.08.001Get rights and content

Abstract

Medication use in hospitals is a complex process and is dependent on the successful interaction of health professionals functioning within different disciplines. Errors can occur at any one of the five main stages of prescribing, documenting, dispensing or preparation, administering and monitoring. The responsibility for the error is often placed on the nurse, as she or he is the last person in the drug administration chain whilst more pressing underlying causal factors remain unresolved.

This paper demonstrates how hierarchical task analysis can be used to model drug administration and then uses the systematic human error reduction and prediction approach to predict which errors are likely to occur. The paper also puts forward design solutions to mitigate these errors.

Introduction

Improving the quality and safety of patient care has become an increasingly high priority in both the UK and across the world. Medical errors affect 850,000 people in the UK each year, often leading to patients spending extended time in hospital or in community care. These errors cost the National Health Service (NHS) up to £2 billion in additional treatment and the cost of clinical negligence settlements is about £400 million (DOH, 2000). The NHS was set up in 1948 by the concurrent government to provide free healthcare for the British public. It has changed and evolved since then but its remit is still the same.

Many of the major medical error studies have highlighted medication errors as a cause of adverse events suffered by patients (Bates et al., 1995; Leape et al., 1995; Brennan et al., 1991; Kohn et al., 1999). Ferner and Aronson (2000) define a medication error as “a failure in a drug treatment process that leads to or has the potential to lead to harm to the patient.” The definition most commonly used is that given by the National Co-ordinating Council for Medication Error Reporting and Prevention (NCC MERP) in the USA:

…any preventable event that may cause or lead to inappropriate medication use or patient harm, while the medication is in the control of the healthcare professional, patient or consumer. Such events may be related to professional practice, healthcare products, procedures, and systems including: prescribing; order communication; product labelling, packaging and nomenclature; compounding; dispensing; distribution; administration; education; monitoring and use.

Medication use is complex and is dependent on the successful interaction of health professionals functioning within different disciplines. Errors can occur at any one of the five main stages of prescribing, documenting, dispensing or preparation, administering and monitoring. Wolf (1993) has pointed out that nurses make medication errors regardless of their speciality and that errors occurred on medical and surgical floors, postpartum units, emergency units and intensive care units.

The responsibility for the error is often placed on the nurse, as she or he is the last person in the drug administration chain. A parallel can be drawn with aviation. Pilots used to be held responsible for aviation accidents until analysis revealed that other factors were highly significant. The reality is that there are many different causes of medication errors and they often combine to cause the incident. For instance, commonly reported reasons due to organisational factors are workload, constant interruptions, shift patterns (Ferner, 1995), communication failures (Fiesta, 1998) and long working hours (DOH, 2000). Thornton et al. (1999) cite lack of proficiency in the calculation of drug doses, dilutions and rates of administration; incorrect preparation or compounding of drugs; and inappropriate drug selection and using incorrect routes of administration. Leape et al. (1995), in addition to the above, identified lack of information about the patient; rule violations (failure to follow accepted and well-established procedures); slips and memory lapses in which the individual “knew better” and could not explain why the error occurred; and drug stock or delivery problems.

In the UK many hospitals use a ward pharmacy system. However, this is in a state of transition to a system that uses the patient's own drugs. In the ward pharmacy system, a large proportion of the medications administered are held as ward stock. These drugs are the most frequently used and are stocked in bottles of 50 or 100 tablets or capsules and are kept in a locked trolley along with non-stock items. Nurses make a drug administration round four to six times daily, depending on the ward during which the trolley is taken to each patient's bed. The patient's own drug system enables the patient to continue using medication they would normally use at home whilst in hospital. This is kept in a locked cabinet at the bedside.

Successful drug administration is dependent on an effective patient information and patient monitoring system. Some drugs have a limited therapeutic range and various indicators (such as blood pressure, heart rate, anticoagulant levels) have to be checked before they can be administered in the appropriate quantity. Medical staff also need to know which drug is needed and when. This cannot be accurately ascertained in the absence of the medication chart. Physicians use the patient's chart to indicate to the nurse which medications the patient is to receive. This is kept with the patient and used to record drug administration. The order includes the drug name, the dose, the route and the drug administration round when it is to be administered. Each dose administered is recorded on the medication chart, which usually allows 14 days of documentation. This allows the patient's most recent drug history to be viewed. Pharmacists visit their designated wards daily to review all patient charts, performing a clinical and supply function (Dean et al., 1995). If a drug is ordered that is not held as ward stock or is not in the patient's bedside drug cabinet, the pharmacist makes a note on the medication chart and a supply sufficient for several days is dispensed with the patient's name on the container.

Giving medications to patients is a fundamental nursing role. It is also a complex activity that carries a high risk of error, as the involvement of different healthcare professionals means that errors may occur at any stage of the process (Hand and Barber, 2000). Nurses seek to give medications correctly or perfectly. However their efforts are often confounded by poorly written prescriptions, constant interruptions, conflicting demands and high workloads.

Section snippets

Addressing the problem

Failure mode and effects analysis (FMEA) has been applied to drug administration as a process of continuous quality improvement and is usually carried out by an interdisciplinary group of healthcare professionals (Cohen et al., 1994). An FMEA anticipates what errors can be made and what the results will be. Thus for each medication the analyst will ask what will happen when someone mistakes a drug package for something else, uses the wrong amount of drug, gives the drug to the wrong patient,

Discussion

The main purpose for carrying out this analysis was to demonstrate the types of error that occur during drug administration and where in the process these errors occur. The analysis predicts what steps can be taken to achieve resolution and highlights those aspects of the drug administration process where design solutions would have the greatest impact.

Many of the tasks presented in the HTA could be subdivided into further levels of component tasks and operations, thus revealing a highly

Conclusion

This paper illustrates how a human error identification technique can be applied to the process of administering drugs to hospitalised patients as a means of preventing error or reducing the effects of error. Schneider (2002) advocates the benefits of applying human factors to the issue of medication errors and makes the point that healthcare providers need to be more aware of the limits of human performance and that system changes need to be made to accommodate these limits. Whilst this paper

Acknowledgements

We thank the reviewers for their comments. This work was funded by the Anthony Anson Medical Fund.

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