Related Experiment Video
Updated: Jan 21, 2026

Induction and Monitoring of Adoptive Delayed-Type Hypersensitivity in Rats
Published on: October 1, 2007
[Evaluation of Bispectral Index time delay in response to anesthesia induction: an observational study]
Ana Leitão Ferreira1, Joaquim Gabriel Mendes2, Catarina Sofia Nunes3
1Universidade do Porto, Faculdade de Engenharia, Porto, Portugal; Centro Hospitalar do Porto, Serviço de Anestesiologia, Centro de Investigação Clínica em Anestesiologia, Porto, Portugal.
Background And Objectives:
According to the manufacturer, the Bispectral Index (BIS) has a processing time delay of 5-10s. Studies addressing this have suggested longer delays. We evaluated the time delay in the Bispectral Index response.
Methods:
Based on clinical data from 45 patients, using the difference between the predicted and the real BIS, calculated during a fixed 3minutes period after the moment the Bispectral Index dropped below 80 during the induction of general anesthesia with propofol and remifentanil.
Results:
The difference between the predicted and the real BIS was in average 30.09±18.73s.
Conclusion:
Our results may be another indication that the delay in BIS processing may be much longer than stated by the manufacture, a fact with clinical implications.
More Related Videos
07:54Drug-Induced Sleep Endoscopy DISE with Target Controlled Infusion TCI and Bispectral Analysis in Obstructive Sleep Apnea
Published on: December 6, 2016
05:44Novel Methods for Intranasal Administration Under Inhalation Anesthesia to Evaluate Nose-to-Brain Drug Delivery
Published on: November 14, 2018
Related Concept Videos
Observational Studies
There are three types of observational studies – Prospective, retrospective, and cross-sectional.
Prospective Study
Prospective studies, also known as longitudinal or cohort studies, are carried out by collecting future data from groups sharing similar characteristics. One...
Naturalistic Observations
General Anesthesia: Overview
General anesthesia induces unconsciousness in the whole body, while the others target specific areas or sensations. It is administered to minimize adverse effects, maintain...
Stages of General Anesthesia
Actor-Observer Effect
Observational Learning