Testing the involvement of baroreflex during general anesthesia through Granger causality approach

Area of Science:

• Anesthesiology
• Cardiovascular Physiology
• Autonomic Neuroscience

Background:

• Baroreflex sensitivity (BRS) assessment typically relies on spontaneous heart period (HP) and systolic arterial pressure (SAP) fluctuations.
• General anesthesia can impair autonomic function, potentially hindering the accurate estimation of BRS from spontaneous variability.

Purpose of the Study:

• To investigate the validity of using spontaneous variability to infer BRS under general anesthesia.
• To determine if Granger causality methods can establish a relationship between SAP and HP during different anesthetic strategies.

Main Methods:

• Application of two Granger causality approaches (F-test and Wald test).
• Analysis of data from two distinct anesthesiological strategies: sevoflurane plus remifentanil and propofol plus remifentanil.

Main Results:

• A significant Granger-causality was identified from SAP to HP.
• This causal relationship was observed independently of the specific anesthesiological strategy employed.

Conclusions:

• Techniques estimating BRS from spontaneous variability are applicable during general anesthesia.
• The findings support the continued use of spontaneous variability methods for BRS assessment in anesthetized patients.