Coherence analysis overestimates the role of baroreflex in governing the interactions between heart period and systolic arterial pressure variabilities during general anesthesia

Tito Bassani, Vlasta Bari, Andrea Marchi, Maddalena Alessandra Wu, Giuseppe Baselli, Giuseppe Citerio, Alessandro Beda, Marcelo Gama de Abreu, Andreas Güldner, Stefano Guzzetti, Alberto Porta

Research output: Contribution to journalArticle


During general anesthesia positive pressure mechanical ventilation (MV) profoundly affects intrathoracic pressure and venous return, thus soliciting cardiopulmonary reflexes and modifying stroke volume. As a consequence heart period, approximated as the temporal distance between two consecutive R peaks on the ECG (RR), and systolic arterial pressure (SAP) variability series are usually highly correlated at the MV frequency (MVF) and this significant correlation is commonly taken as an indication of an active baroreflex. In this study the involvement of baroreflex was tested according to a time-domain linear Granger causality approach accounting explicitly for MV in two experimental protocols. In the first protocol volatile (VA) or intravenous (IA) anesthetic was administered in humans during pressure controlled MV (PCMV). In the second protocol IA was administered in pigs during PCMV or pressure support MV (PSMV). Causality analysis was contrasted with RR-SAP squared coherence. Significant coherence values at MVF were always found in both protocols. On the contrary, a significant causal link from SAP to RR was less frequently found in humans independently of the anesthesiological strategy and in animals during PCMV. PSMV was superior to PCMV in animals because it was able to better preserve a link from SAP to RR. During general anesthesia the involvement of baroreflex in governing RR-SAP variability interactions is largely overestimated by RR-SAP squared coherence and causality analysis can be exploited to rank anesthesiological strategies and MV modes according to the ability of preserving a working baroreflex.

Original languageEnglish
Pages (from-to)83-88
Number of pages6
JournalAutonomic Neuroscience: Basic and Clinical
Issue number1-2
Publication statusPublished - Nov 2013



  • Baroreflex
  • Cardiovascular control
  • Coherence analysis
  • General anesthesia
  • Granger causality
  • Heart rate variability

ASJC Scopus subject areas

  • Clinical Neurology
  • Cellular and Molecular Neuroscience
  • Endocrine and Autonomic Systems

Cite this