Cohort study for evaluation of dose omission without justification in a teaching general hospital in Bahia, Brazil.

OBJECTIVE

To evaluate the incidence of medication errors due to dose omissions and the reasons for non-administration of medications.

DESIGN

A cohort study blinded to the nursing staff was conducted for 5 consecutive days to evaluate administration of prescribed medications to selected inpatients.

SETTING

A major academic teaching hospital in Brazil.

PARTICIPANTS

Dispensed doses to patients in medical and surgical wards.

MAIN OUTCOME MEASURES: Doses returned to pharmacy were evaluated to identify the rate of dose omission without a justification for omission.

RESULTS

Information was collected from 117 patients in 11 wards and 1119 doses of prescribed medications were monitored. Overall, 238/1119 (21%) dispensed doses were not administered to the patients. Among these 238 doses, 138 (58%) had no justification for not being administered. Failure in the administration of at least 1 dose occurred for 58/117 (49.6%) patients. Surgical wards had significantly more missed doses than that in medical wards (P = 0.048). The daily presence of a pharmacist in the wards was significantly correlated with lower frequency of omission errors (P = 0.019). Nervous system medications were missed more significantly than other medications (P < 0.001). No difference was noted in the omission doses in terms of route of administration.

CONCLUSIONS

High incidence of omission errors occurs in our institution. Factors such as the deficit of nursing staff and clinical pharmacists and a weak medication dispensing system, probably contributed to incidence detected. Blinding nursing staff was essential to improve the sensibility of the method for detecting omission errors.