Autonomic Nervous System Activity for Risk Stratification of Emergency Patients With Pneumonia

Abstract

BackgroundCommunity-acquired pneumonia (CAP) causes appreciable morbidity and mortality in adults, especially in those ≥65 years of age. At hospital admission, an immediate and reliable risk assessment is necessary to detect patients with possible fatal outcome. ObjectiveWe aimed to evaluate markers of the autonomic nervous system based on an electrocardiogram to predict mortality in patients with CAP. MethodsFor this purpose, the deceleration capacity (DC) of heart rate was calculated in 253 patients who presented to the emergency department with CAP. The 30-day mortality rate was defined as the primary endpoint (PEP). The secondary endpoint was the total mortality within 180 days. ResultsPEP was reached in 33 patients (13%). The DC, measured in milliseconds, was significantly lower in patients who reached the PEP than in those who did not (2.3 ± 1.5 ms vs. 3.6 ± 2.3 ms, p = 0.004). The DC was also significantly lower in nonsurvivors than in survivors at the time of the secondary endpoint (2.3 ± 1.5 ms vs. 3.7 ± 2.4 ms, p < 0.001). Our results indicate that DC is an independent predictor of 30- and 180-day mortality. ConclusionDC was independently associated with death from CAP in our study. As a practical consequence, DC could be useful in triage decisions. Patients with certain high risks could benefit from adjuvant treatment and special medical attention.