Abstract: Objective: To investigate the status quo of nursing interruption events during the course of administration by nurses, so as to provide basis for developing preventive strategies of nursing interruption events. Methods: Nurses' drug delivery process was divided into three phases according to the time of clinical practice: doctor's order processing, drug allocation and bedside drug administration. Structured observation method was employed to observe the frequencies, sources, types and consequences of nursing interruption events during the three phases in the Department of Cardiology from September 2018 to February 2019. The interruption time, medication errors caused by the interruption and the influencing factors of interruption were analyzed. Results: After 270 hours of observation, 3424 nursing interruption events occurred, with an average of 12.68 times per hour. The distribution of event types in the three phases and the distribution of consequences were statistically significant (P<0.001). The average interruption time was (28.01±10.99) seconds each time, and the total interruption time of drug administration was 26.65 hours, accounting for 9.87% of the total observation time. There was no statistical difference in the average interruption time of the three phases (P=0.209). During the time of interruption, there were 39 potential incidents of medication errors, with the incidence of 11.39‰. The sources of interruption events were as follows: family members, environment, doctors, patients, colleagues, nurses themselves and others, of which 2340 were low priority events, accounting for 68.34%. Conclusion: Nursing interruption events occur frequently, come from many sources, have complex causes and common negative outcomes. There are high proportions of low priority events, which actually reflect patients' needs. Interruption also has time cost, and can directly lead to medication errors. It is of great importance to provide predictive services for patients to avoid or reduce unnecessary interruptions during the process of nursing medication, so as to meet patients' needs, save the wasted time, and ensure the safety of drug administration.

Key words: drug administration; interruption; nursing; reason