This Is AuburnElectronic Theses and Dissertations

The Effect Of Illumination On Medication Preparation Errors In A Long Term Care Facility




Varadarajan, Ranjani

Type of Degree



Pharmacy Care Systems


The main objectives of this study were to (1) measure the effect of increased illumination levels on the medication preparation error rate in a long term care facility, and (2) measure the effect of increased illumination levels on the medication preparation error types in the same facility. The data collection process was divided into two phases: 1. Initial site visit to explore and operationally define the variables of interest and collect demographic information about the subjects in the study. 2. Explanatory phase to study the effect of the intervention variable (increased illumination level) on the dependant variable (medication preparation errors). The sampling unit was the preparation of an oral prescription medication dose by the nurse-subject in the particular section of the study site and observed by the principal investigator, before administration to the resident, during the study period. The data were collected by direct, undisguised observation method during the morning and evening medication pass shifts (8 am and 5 pm) at the study site, during a period of 45 days. The doses observed were randomly assigned for illumination at one of three levels of illumination (baseline, 100 and 145 foot-candles). Each nurse was observed for doses at all three illumination levels, thus each subject served as their own control. The illumination was controlled by a supplemental lighting apparatus (OttLite 508 IlluminationTM rechargeable fluorescent task lamp), which was affixed to the study medication cart. Seven nurse-subjects prepared a total of 6,758 doses during the observation period, of which 467 doses were in error (error rate 6.7%). The most frequently observed medication preparation error was Omission (N = 190, 40%), followed by Wrong time (N = 146, 31%), Wrong form (N = 72, 15%), Wrong Dose (23, 5%) and Unauthorized Dose (4, 1%). A repeated - measures Analysis of Variance (ANOVA) was performed on the observation data for the study period. Significant treatment (illumination) effect (F2,5 =17.116, p < 0.05) was found on the medication preparation error rate, with Illumination level 3 (145 foot-candles; error rate 4.3%) significantly associated with lower medication preparation error rate as compared to the baseline illumination level (30 foot-candles; error rate 8.5%). Chi Square Analysis revealed Wrong dose form errors (X2 =12.954, df =2, p < 0.05) and Omission errors (X2 =180825, df =2, p < 0.05) to have significant relationship with the illumination level. Linear regression analysis revealed no significant linear relationship between medication preparation workload of the nurse-subjects and their medication preparation error rate for all three illumination levels (Level 1: F1,26 = 0.196, p > 0.05, Level 2: F1,26 = 0, Level 2: p > 0.05, Level 3: F1,26 = 0.122, p > 0.05). There were no significant differences in the proportion of medication preparation errors for each nurse-subject for all three illumination levels. It was concluded that adjustment of lighting from baseline level to 145 foot-candles achieved significant reduction in medication preparation errors. An important implication of this study is that the elevation of illumination standards at long- term care facilities could reduce the rate of errors in the preparation of doses for administration on the order of 50%. The study directed attention to the need for setting higher illumination standards at long-term care facilities, in order to facilitate optimum visual performance by the healthcare staff.