PURPOSE: Evaluate gender-based autonomic (ANS) differences in 1) early sepsis, and 2) septic related hemodynamic patterns and associated outcomes.
METHODS: Shortly after admission to emergency dept., concurrent autonomic and hemodynamic patterns were monitored in 208 consecutive severely ill septic and septic shock patients; 48 females (23%). Simultaneous respiratory rate (RR) variability and heart rate (HR) variability (HRV) spectral patterns were collected and used to compute ANS parameters. Low Frequency area (LFa) and Respiratory Frequency area (RFa), are measures of sympathetic (SNS) and parasympathetic (PSNS) activity, respectively, according to the MIT approach to spectral analysis of HRV with RR spectral analysis. Noninvasive hemodynamic monitoring included: a) cardiac index (CI) by bioimpedance, HR, and mean arterial pressure (MAP) reflecting cardiac function, b) pulse oximetry (SapO2) reflecting changes in pulmonary function, and c) transcutaneous oxygen (PtcO2) indexed to the FiO2 reflecting tissue perfusion.
RESULTS: ANS branch activity as measured by HRV with respiratory analysis correlates with that as measured by the standard approach (HRV without respiratory analysis): for the two SNS measures r=0.72, p=0.00, sig.=0.01; for the two PSNS measures r=0.52, p=0.0, sig.=0.01. The only ANS measure associated with outcomes was RFA: survivors’ RFa averaged 18.86 bmp2 and non-survivors’ RFa averaged 30.00 bpm2 (p=0.06).Initially, female nonsurvivors had greater RFa (PSNS activity), while male survivors had greater LFa (SNS activity). Nonsurvivors’ increases of both genders occurred early, i.e., in the first day of admission. In survivors, these ANS patterns were associated with increased CI & HR, normal MAP, SapO2, & PtcO2/FiO2. Nonsurvivors had normal CI, hypotension, tachycardia, low PtcO2/FiO2 & SapO2, and reduced oxygen delivery. Sudden surges of increased autonomic activity, especially in nonsurvivors, were associated with increased HR, MAP, & CI, and tendencies toward reduced PtcO2/FiO2 With decreased SNS and PSNS activity, the opposite hemodynamic changes occurred.
CONCLUSION: Increased autonomic activity was greater in females and greater in those who died; especially females. Overall, the salient difference between survivors and non-survivors was parasympathetic activity.
CLINICAL IMPLICATIONS: ANS changes associated with sepsis show gender differences.
DISCLOSURE: Joseph Colombo, Shareholder Joe Colombo (only) owns shares of the ANS monitoring company Ansar, Inc.; Employee Joe Colombo (only) is employed by the ANS monitoring company Ansar, Inc.