Abnormal vital signs are associated with an increased risk for critical events in US veteran inpatients☆
Received 20 April 2009; received in revised form 21 June 2009; accepted 9 August 2009. published online 10 September 2009.
Abstract
Aim
Establish the frequency of abnormal vital signs in medical and surgical ward patients; study their association with “critical events,” which for the purposes of this study, were mortality, cardiac arrests and unplanned ICU transfers.
Design and methods
Four-month prospective, observational cohort study; University-affiliated US Veteran's hospital. Vital signs from all regular ward medical and surgical inpatients were recorded over the study period and compared with records of cardiac arrests, mortality and ICU admissions.
Results
Using the Hospital's Medical Emergency Team criteria to define normal/abnormal thresholds for vital signs, abnormal vital signs (VSMET) were found in 16% of patients; of these; 35% experienced a critical event vs. 2.5% in the patients with normal vital signs (OR 21, 95% CI 12–35, p<0.001). The sensitivity of VSMET to predict a critical event was 0.72 and the positive predictive value was 0.35; sensitivity decreased to 0.28 and positive predictive value increased to 0.78 for patients that had two different VSMET. Survival was significantly lower in both medical and surgical patients with VSMET at both 30 days and at 1 year following discharge (p<0.02). Both medical and surgical patients with VSMET had twice the length of stay of patients with normal vitals (3 vs. 7 days; p<0.001).
Conclusions
Even single recordings of VSMET signaled increased risk for critical events in hospital ward patients. Use of vital signs as criteria for additional patient assessment and possible ICU admission appears justified. Development of abnormal vitals during hospitalization may signify impaired physiologic reserve that places a patient at higher risk for mortality after discharge.
aDepartment of Anesthesia, Stanford University School of Medicine, Stanford, CA 94305, United States
bDepartment of Anesthesiology, Veterans Affairs Medical Center, Palo Alto, CA 94304, United States
Corresponding author at: Department of Anesthesia, MC 112A, Veterans Affairs Medical Center, 3801 Miranda Avenue, Palo Alto, CA 94304, United States. Tel.: +650 493 5000x66756; fax: +650 852 3432.
ABSTRACT