Autonomic predictors of recovery following surgery: A comparative study

Abstract

Although heart rate and temperature are continuously monitored in patients during recovery following surgery, measures that extract direct manifestations of neural regulation of autonomic circuits from the beat-to-beat heart rate may be more sensitive to outcome. We explore the relationship between features of autonomic regulation and survival in the prairie vole, a small mammal, with features of vagal regulation of the heart similar to humans. Cardiac vagal regulation is manifested in the beat-to-beat heart rate variability (HRV) pattern and can be quantified by extracting measures of the amplitude of periodic oscillations associated with spontaneous breathing. Thus, monitoring beat-to-beat heart rate patterns post-surgery in the prairie vole may provide an opportunity to dynamically assess autonomic adjustments during recovery. Surgeries to implant telemetry devices to monitor body temperature and continuous ECG in prairie voles are routinely performed in our laboratory. Ten of these implanted prairie voles died within 48 h post-surgery. To compare the post-surgery autonomic trajectories with typical surviving prairie voles, the post-surgery data from 17 surviving prairie voles were randomly selected. The data are reported hourly for 27 prairie voles between 6 and 14 h (1 h before the demise of the first subject) post-surgery. Receiver operator curves were calculated hourly for each variable to evaluate sensitivity in discriminating survival. The data illustrate that measures of HRV are the most sensitive indicators. These findings provide a foundation for investigating further neural mechanisms of cardiovascular function.

Acoustic features of prairie vole (Microtus ochrogaster) ultrasonic vocalizations covary with heart rate

“…Although the voles in this study were selected for inclusion based on having high vagal regulation of heart rate, voles with less vagal regulation of heart rate might have a weaker covariation between acoustic features of vocalizations and heart rate. This rule of inclusion excluded voles that did not express an optimal physiological state following surgery (see [14, 34]). Interestingly, the cage relocation challenge was sufficiently stressing to disrupt the vagal dominance in heart rate regulation, which was observed by low nonsignificant correlations between heart period and RSA.…”

Autonomic, behavioral and neuroendocrine correlates of paternal behavior in male prairie voles

“…RSA was assessed using time-frequency procedures [34, 35] described in detail elsewhere [30, 31, 36]. RSA was operationally defined as the natural log of the sum of the power within the respiratory bandwidth of 1.0–4.0 Hz.…”

Autonomic Substrates of the Response to Pups in Male Prairie Voles

“…RSA was assessed using standardized procedures [22]–[24], which were modified for the frequency band of spontaneous breathing the vole and described in detail elsewhere [19], [20], [25]. RSA was operationally defined as the natural log of the sum of the power within the respiratory bandwidth of 1.0–4.0 Hz.…”