Incidence and significance of clinically abnormal events in a tertiary referral medical center: implementation of the clinical alert system (CAS).

Background: The prognosis of in-hospital cardiopulmonary arrest remains very poor. Reports have shown patients often have clinically abnormal events prior to arrest. To improve patient outcome and prevent arrest, detection of the abnormal events with early intervention has been advocated. However, the incidence of these events in Taiwan and their clinical significance remain unclear.

Methods: We conducted a prospective observational study with the implementation of the clinical alert system (CAS) in a university-affiliated tertiary referral medical center. Clinically abnormal events were detected using the CAS criteria for acute physiologic deterioration, and reported to experienced physicians for management. Patient and report data were retrieved, collected and analyzed.

Results: During the 14-month study period, a total of 2,050 events were detected in 1,640 patients. The estimated incidence of the events was 3.19 per 1,000 bed-days, which occurred in 2.14% of admissions. The most common event was abnormal heart rate (36.5%), followed by desaturation (26.7%), abnormal respiratory rate (24.5%), and abnormal blood pressure (23.1%). The majority of the events were reported in the day time, and nurses contributed most of the reports (66.4%). The 30-day and in-hospital mortality rates were 26.3% and 34%, respectively. Multivariate survival analysis showed that desaturation (relative risk [RR] = 1.715; p < 0.001), abnormal respiratory rate (RR = 1.652; p < 0.001), abnormal blood pressure (RR = 1.460; p = 0.001), coma (RR = 1.918; p < 0.001), and oliguria (RR = 1.424; p = 0.0024) were significantly associated with 30-day mortality. Mortality of patients in the last 2 months was significantly lower than that in the first 2 months (20.5% vs. 35.4%; p < 0.001), which suggests the effectiveness of the CAS.

Conclusion: The development of clinically abnormal events is associated with poor outcome, which suggests that early detection and timely management of these events is necessary. Implementation of the CAS may improve the in-hospital outcome of these patients.