Causes of Medication Administration Errors in Hospitals: a Systematic Review of Quantitative and Qualitative Evidence

3.4.1.1 Unsafe Acts

Seven studies reported usable data matching Reason’s description of active failures [34, 40, 41, 44, 53, 56, 57, 62, 88]. The majority of studies identified primary causes of MAEs that could be attributed to the individual responsible for the error without using an established framework. These were broadly considered as either slips, lapses, mistakes or violations.

Slips and lapses. Slips and lapses were common, being identified by 29 studies (53.7 %). Misidentification of either medication or a patient were among the most frequently reported events considered as slips [54, 58, 68, 73, 76, 77, 81]. Misreading either a medication label/product, prescription or other documentation was also common [34, 40, 51, 52, 54, 58, 64, 77, 78]. Staff confused look-a-like or sound-a-like medication names, patient names and medication packaging, which led to MEs [42, 43, 45, 56, 59, 63, 64, 69, 71, 72, 82, 85, 87]. Mental states such as lack of concentration, complacency and carelessness were also reported [51, 52, 78]. Most of the data was presented in tabular or list form in article texts; more detailed examples from qualitative interviews, focus groups or open-ended surveys were able to identify the cause(s) of their slips and lapses [34, 40, 41, 42, 43, 44, 45, 53, 62, 63, 73, 88]; these included nurses forgetting to sign a medication order or misreading labels due to being busy and/or distracted [42, 43, 45, 53, 88], failing to administer a drug or being careless due to heavy workload, poor staffing and/or being distracted [42, 43, 45, 73] and selecting the wrong medication due to pressure from others or busy/distracting environments [63].

Knowledge- and rule-based mistakes. Knowledge-based mistakes were less frequent (n = 16), with staff explaining that they did not know enough about the medication they were administering [34, 40, 41, 44, 51, 52, 56, 66, 77, 78, 82], the infusion pump they were using [58] or the patient to whom they were administering it [56, 82]. Rule-based mistakes were generally not observed [88].

Violations. Violations were reported by 14 studies, which were limited predominantly to data collection methods involving (at least in part) conversations with subjects to determine error causality. Where enough data were provided, situational violations (those arising due to necessity [e.g. poorly designed protocols, lack of staff]) were noted [53, 58, 67, 77, 78, 88]. Reasons for violations included trusting senior colleagues [63], patients requests [77], lack of access to suitable administration protocols [88], patient acuity [58, 88], acting in the patients’ interests (e.g. to avoid harm or optimise treatment) [53, 60, 66], poor supervision/drug knowledge (associated with fast bolus intravenous administration) [34, 40], lack of staff (intentionally giving drugs early/late) [58, 67, 78] and common accepted practice (administering without a signed prescription) [53]. One nurse gave paracetamol 4 hourly instead of the prescribed 6-hourly regimen because they thought it would not be effective if given 6 hourly [66].

Other unsafe acts. Calculation errors [39, 48, 50, 52, 64, 74, 77, 78, 80, 87] and faulty checking activities [6, 7, 42, 43, 45, 56, 63, 72, 75, 77, 78, 80, 81, 82, 86] were commonly reported. Difficulty with infusion equipment was also noted [42, 43, 45, 56, 58, 76, 83]. Other errors included not following instructions; insufficient evidence existed to determine whether these were deliberate acts (and hence violations) [51, 52, 77].

3.4.1.2 Latent Conditions

Error- or violation-producing conditions describe the circumstances in which errors occur, and arise due to high-level managerial decisions. Multiple conditions can lead to one unsafe act [36].

The patient. A total of 17 (31.5 %) studies reported patient characteristics as causes of MAEs. Logistical problems associated with delivery of medication were most common and included lack of, difficulty with or delays waiting for intravenous access [34, 39, 40, 49, 50, 67, 68] (leading to wrong route [39], deterioration of medication [49], omission [50], wrong time [49] and compatibility errors [39]), and absent/sleeping patients during drug administration rounds [49, 51, 67, 76, 88]. Severity of patient illness (acuity) was reported by seven studies [42, 43, 45, 54, 55, 82, 86, 88]; some studies provided examples of resulting errors, which included wrong time or dose omission and, in many cases, the nurses were aware of their actions, which would constitute a violation [54, 58, 88]. Patient behaviour also led to MAEs through non-cooperation [34, 40, 51, 85], or prevented errors though knowledge of medications [73].

Policies and procedures. Problems with policies or procedures were reported on few occasions (n = 6). Examples included absence of a policy [41, 44, 56] and policies that were considered over-laborious [42, 43, 45], or generally unsuitable [34, 40, 41, 44, 88] (which led to wrong dose and time violations in one study [88]). Nurses reported that they had only basic information to help them safely mix and administer intravenous medications [41, 44]. Nurses were unclear about the role of the second checker in one study, which contributed to MAEs [53].

Ward-based equipment. Problems with equipment used to aid drug administration contributed to MAEs (n = 19). Insufficient equipment (computers [62] or gloves [78]) [88], malfunctioning equipment [86] and ambiguous equipment design (e.g. syringe driver, drug packaging) [34, 40, 41, 44, 50] were reported; more general problems with drug charts included a lack of access [38, 50] and misplacement [50, 77], which combined with distractions and a noisy environment to lead to a wrong drug error in one interview study [63]. Example(s) of the nature of the infusion pump problems were given by a few studies, which reported that doses could either be administered incorrectly due to being un-calibrated [77] or malfunctioning (a nurse commented how she expected the pump to work because it was well tested) [61], or not be administered at all due to different pump properties [88] or pumps that were not connected [78].

Health and personality. Physical feelings of fatigue, tiredness/sleep deprivation, sickness and general discomfort amongst staff were reported as contributory factors to errors (n = 13) [42, 43, 45, 51, 52, 63, 64, 65, 68, 70, 71, 72, 82, 86, 88]. More detailed analysis of error accounts by one interview study revealed cases where physical exhaustion was caused by long hours and lack of breaks/food [63]. Staff member mental state at the time of error occurrence was also reported to lead to errors; stress [42, 43, 45, 51, 52, 62, 64], boredom [68], nervousness (with being busy and young) [42, 43, 45] and poor mood [82] were all found to be associated, though their origins were not stated. Personality-related causes were briefly reported as a lack of assertiveness/confidence [52] (including when challenging medical staff [51]), error perception [88] and conscientiousness [51].

Training and experience. Staff inexperience played a role in contributing to errors (n = 8) [34, 40, 42, 43, 45, 52, 72, 82, 86, 87, 88]. This included being unfamiliar with the medication, environment, procedures or equipment, as well as being ‘new’ [42, 43, 45, 82, 87]. The feeling of being a newly qualified nurse in post was found in open-ended survey questions to be related to violation-type errors as nurses obeyed/trusted senior colleagues and felt pressure to complete their rounds on time, which led to them not performing their own safety checks [42, 43, 45]. Insufficient training and experience has strong links with knowledge- and rule-based mistakes [34, 40, 41, 44, 53, 88].

Inadequate training was also reported (n = 6), but few specifically mentioned training regarding the practicalities of preparing and administering medication [34, 40, 41, 44, 85]; one study reported that nurses felt their intravenous drug administration skills were not assessed appropriately [34, 40], which may have contributed to nurses learning these skills from each other on the ward [34, 40, 41, 44].

Communication. Difficulty with written communication featured prominently (n = 19), with two studies reporting that illegible [51, 64] and five unclear/messy [34, 40, 41, 44, 55, 77, 82] prescriptions contributed to MAEs. Transcription errors were reported by some [37, 41, 42, 43, 44, 45, 50, 76, 83, 85], as were MAEs (e.g. omission and extra dose errors) apparently caused by others’ documentation errors when writing prescriptions or administering medication [42, 43, 45, 50, 60, 65, 67, 77, 78], with open-ended surveys and interviews relating one case to misinterpreting the roles of nursing students and their supervisors [42, 43, 45]. Studies commonly reported more general communication difficulties between healthcare staff or other services without specifying their nature (n = 15). Those using interviews/conversations (± direct observation) and open-ended survey methods reported instances where nurses/doctors failed to pass on information or successfully passed on incorrect information to their colleagues resulting in a drug administration delays [66, 67], drugs being given that should have been withheld [77] and incorrect doses being administered [42, 43, 45, 54]. Problems with labelling were also frequently reported, though detail on their nature and relationship to other causes was missing [49, 68, 70, 71, 72, 81, 82, 86].

Supervision and social dynamics. Poor supervision by senior colleagues appears to have a role to play in MAE causation, manifesting as pressuring students to administer drugs more quickly, not supervising or assisting closely enough or giving unclear/incorrect instructions (n = 4) [34, 40, 42, 43, 45, 63, 86]. As discussed previously, specific error examples appear to link poor supervision to violation-type errors and the provoking conditions of inexperience, trusting colleagues and fatigue [34, 40, 42, 43, 45, 63], though supervision has also been linked to poor equipment and workload in one example [42, 43, 45]. Two studies reported apparent overconfidence in/from other nurses when either communicating instructions (as a cause of a wrong dose error) [42, 43, 45] or carrying out independent checks (a dose calculation error) [74]. Pressure from other staff members [42, 43, 45, 71], confronting and intimidating behaviour [64] and social isolation from colleagues also feature as causes [42, 43, 45]. There were examples of how proper supervision and communication could maintain patient safety, through co-workers identifying errors before they reached the patient [54, 63, 73].

Workload and skill mix. Heavy staff workload (n = 19) appeared an important contributor to MAEs, and includes end of shift/patient transfer pressures, patient load and multitasking [34, 40, 41, 42, 43, 44, 45, 67]. Resulting errors included omissions [60] and violations [67, 88], though one study found that workload appeared not be a contributory factor (along with most other latent conditions) [57]. Workload was found to combine with distractions to lead to errors in intravenous administration [34, 40] and with patient acuity, inexperience or local working practice to lead to other errors [42, 43, 45, 62].

Skill mix of staff was identified by six studies, with two stating a lack of qualified staff [34, 40, 51] and others that working with inexperienced or new staff members contributed to MAEs [64, 72]. Short staffing was reported by six studies as a cause of MAEs [42, 43, 45, 51, 64, 78, 82].

Distractions and interruptions. Sixteen studies found that interruptions/distractions were a cause of MAEs, though details of the nature of these distractions or their interplay with other contributory factors were rarely given. Of these studies, those using interviews/conversations (± observation) or surveys with open-ended questions provided more descriptive data; examples of resulting errors/near errors included wrong drug [58], wrong time [34, 40] and wrong dose calculations [88]. Distractions included ward rounds [34, 40] or face-to-face/telephone conversations with co-workers/patients [42, 43, 45, 63] and were often present with high workload and/or poor supervision [34, 40, 63].

General work environment. Eleven studies reported on the contribution of the general environment; specifically, noise [64], lighting [64, 71], emergencies [88], and busy [34, 40, 42, 43, 45, 54, 58, 73, 85] or chaotic [42, 43, 45, 54] working environments were identified. Studies offering more detail through open-ended survey questions linked these factors to short staffing, workload, patient acuity and poor supervision [42, 43, 45].

Medicines supply and storage. Issues relating to medicines logistics were reported by 27 studies. A lack of ward stock led to omission/wrong time errors [37, 38, 47, 51, 78, 79, 80, 84]. Medication was misplaced or lost on the ward on occasions [47, 62, 75, 81]. In contrast, one study found no errors relating to medication unavailability [50]. The pharmacy department contributed to errors and violations in other cases, through delayed deliveries [50, 55, 66, 76, 85, 88], incorrect dispensing [6, 38, 42, 43, 45, 51, 55, 58] and unavailable stock [58, 78, 79].

Local working culture. Nurses passed on bad practices (e.g. administering without a prescription) that led to errors in three studies [34, 40, 41, 44]. Levels of trust between colleagues [53] and working double shifts or not taking breaks (leading to exhaustion) [42, 43, 45] were additional causes. One nurse described how a wrong drug was selected for administration in a busy and chaotic theatre environment when she/he “relied on routine” [42, 43, 45].

Organisational (high-level) decisions. Included studies rarely reported organisational/high-level decisions as having a direct impact on error occurrence; feedback on errors was considered important by some interview or survey studies using narrative responses to minimise errors in future, and the importance of nurse input in the process was highlighted in one case [42, 43, 45]. Some described supervisory teams responding to errors poorly [63], that opportunities to learn from mistakes were limited [42, 43, 45, 53] and how positive feedback about errors improved nursing practice [63, 64]. More direct causal evidence cited a lack of hospital policy (when challenging other healthcare staff) or misguided policy (low nurse staffing) as causes of MAEs [56, 82], as well as decisions regarding logistical strategy generally revolving around clashes of other ward activities with medication administration [42, 43, 45, 50, 78]. Mix-ups involving medicines that look or sound alike may have roots beyond hospitals with the pharmaceutical industry [34, 40].