Author + information
- 1Department of Emergency Medicine, the Second Affiliated Hospital, Xi’an Jiaotong University, Xi’an, China
- 2Department of Cardiology, the Second Affiliated Hospital, Xi’an Jiaotong University, Xi’an, China
- 3Clinical Research Center, the first Affiliated Hospital, Xi’an Jiaotong University, Xi’an, China
Patients in intensive care unit (ICU) are exposed to enormous pathophysiological and psychological factors, which leads to alterations on sympathovagal balance and variations of continuous blood pressure (BP) monitoring. Although amount of evidences indicated the fluctuations of BP over a certain period could provide additional prognostic value for cardiovascular events and mortality, it remains uncertain whether BP variation could assist risk stratification for critically ill patients. In this study we aimed at exploring the associations of day-night variation (DNV) in mean arterial pressure (MAP) and mortality in non-shock patients in ICU.
This is a retrospective observational cohort study, utilizing a massive ICU database from the Massachusetts Institute of Technology (MIT) and Beth Israel Deaconess Medical Center (BIDMC). The complete data includes all patients admitted to ICUs at BIDMC from 2001 to 2012. A total of 20702 patients were involved in our study, individuals were excluded if the patients (1) were diagnosed as shock; (2) failed to provide continuous MAP records. MAP-DNV of the patients were calculated from continuous bedside blood pressure monitoring data. MAP-DNV was defined as MAP (night)/MAP (day). Then the patients were classified into severe abnormal dipping group (DNV>1.0 or DNV≤0.8), abnormal dipping group (0.9<DNV≤1.0), dipping group (0.8<DNV≤0.9). Then chi-squared test was performed to test the significance of mortality among different groups.
There was increased mortality in severe abnormal dipping group (55.09%) than abnormal dipping group (51.22%) and dipping group (50.02%). The difference between three groups were statistically significant (χ2=34.05, P<0.01). Moreover, severe abnormal dipping group had high mortality rate than abnormal dipping group (χ2=27.20, P<0.01) and dipping group (χ2=18.50, P<0.01), respectively. However, there was no difference between abnormal dipping group and dipping group (χ2=1.085, P =0.298).
Our analysis in non-shock critical ill patients identified three different ranges of MAP-DNV. These results suggested that severe abnormal MAP-DNV might associate with higher mortality in non-shock patients in ICU and may reflect severe damage of sympathovagal balance due to the original diseases.