Heart Rate Variation is The Clinical Sign Associated with The Deepest Plane of Anesthesia During Induction: The Novel Finding and Its Clinical Implications

  • Ting-Hsuan Chiang, MD
  • Sami Strutner, BA
  • Adam Moheban, MD
  • Joseph Rinehart, MD
  • Govind R. Rajan, MD, MBBS, FAACD, FASA
DOI: https://doi.org/10.35975/apic.v27i2.1930
Keywords: Depth of Anesthesia, Patient Safety, Heart rate variation, Induction

Abstract

Background: Premature airway manipulation during induction can lead to adverse patient outcomes. However, there is currently no standardized clinical sign to assess adequate anesthesia depth during induction. With the goal of increasing patient safety during induction, we aim to correlate different clinical signs during induction with the depth of anesthesia using the bispectral index (BIS) monitor and determine the physical metrics corresponding to the deepest plane of anesthesia.

Methodology: This prospective study enrolled 41 subjects scheduled for surgery requiring propofol for induction. A BIS monitor was used for standardized monitoring of anesthesia depth during the induction process. We documented the BIS value and occurrence time of the observed physical metrics: (1) loss of eyelash reflex, (2) loss of response to verbal stimuli, (3) loss of muscle tone, (4) loss of end tidal carbon dioxide (EtCO2) or apnea, and (5) transient heart rate variations.

Results: Apnea, change in heart rate from baseline, and heart rate return to baseline are signs during induction associated with both lower BIS values and later occurrence when compared to other clinical signs such as loss of eyelash reflex, verbal response, and muscle tone (P < 0.001).

Conclusion: Physical signs such as loss of eyelash reflex, verbal response, and muscle tone during induction are associated to lighter planes of anesthesia. A safer and deeper plane of anesthesia occurs later. Relying on these physical signs for assessment of laryngeal mask airway insertion may increase the risk of stimulating the patient’s airway prematurely, which can lead to adverse patient outcomes.

Abbreviations: EtCO2 - End tidal carbon dioxide; BIS - Bispectral index; EEG - electroencephalogram; EKG - electrocardiogram

Key words: Depth of Anesthesia; Patient Safety; Heart rate variation; Induction

Citation: Chiang TH, Strutner S, Moheban A, Rinehart J, Rajan GR. Heart rate variation is the clinical sign associated with the deepest plane of anesthesia during induction: the novel finding and its clinical implications. Anaesth. pain intensive care 2023;27(2):243−249.

DOI: 10.35975/apic.v27i2.1930

Received: October 13, 2022; Reviewed: March 29, 2023; Accepted: March 31, 2023

Author Biographies

Ting-Hsuan Chiang, MD

Clinical Research Specialist, Department of Anesthesiology and Perioperative Care, University of California, Irvine Medical Center, Irvine, California, USA

Sami Strutner, BA

Medical Student, Department of Anesthesiology and Perioperative Care, University of California, Irvine Medical Center, Irvine, California, USA.

Adam Moheban, MD

Resident physician, Department of Anesthesiology and Perioperative Care, University of California, Irvine Medical Center, Irvine, California, USA.

Joseph Rinehart, MD

Research Vice Chair, Department of Anesthesiology and Perioperative Care, University of California, Irvine Medical Center, Irvine, California, USA.

Govind R. Rajan, MD, MBBS, FAACD, FASA

Clinical Professor, Department of Anesthesiology and Perioperative Care, University of California, Irvine Medical Center, Irvine, California, USA.

Published
04-02-2023
How to Cite
MD, T.-H., BA, S., MD, A., MD, J., & Rajan, MD, MBBS, FAACD, FASA, G. (2023). Heart Rate Variation is The Clinical Sign Associated with The Deepest Plane of Anesthesia During Induction: The Novel Finding and Its Clinical Implications. Anaesthesia, Pain & Intensive Care, 27(2), 243-249. https://doi.org/10.35975/apic.v27i2.1930
Issue
Vol 27 No 2 (2023): April 2023
Section
ORIGINAL RESEARCH