title: Comparison of equi-minimum alveolar concentration of sevoflurane and isoflurane on bispectral index values during both wash in and wash out phases: A prospective randomised study.
abstract: OBJECTIVE
  At equal minimum alveolar concentration (MAC), volatile agents may produce different bispectral index (BIS) values especially at low BIS levels when the effect is volatile agent specific. The present study was performed to compare the BIS values produced by sevoflurane and isoflurane at equal MAC and thereby assessing which is a better hypnotic agent.
  
  
  METHODS
  Sixty American Society of Anaesthesiologists I and II patients undergoing elective mastoidectomy were divided into groups receiving either isoflurane or sevoflurane, and at equi-MAC. BIS value was measured during both wash in and wash out phase, keeping other parameters same. Statistical analysis was performed using the Friedman two-way analysis and Mann-Whitney U-test. A P < 0.05 was considered significant.
  
  
  RESULTS
  BIS value was significantly lower with sevoflurane at all MAC values as compared to isoflurane, except in the beginning and at MAC awake. However, both the drugs proved to be cardiostable.
  
  
  CONCLUSIONS
  At equi-MAC sevoflurane produces lower BIS values during wash in as well as wash out phase as compared to isoflurane, reflecting probably an agent specific effect and a deficiency in BIS algorithm for certain agents and their interplay.
authors: Department of Anesthesia, ESI PGIMSR, Basaidarapur, New Delhi, India.
authors: Madhu
authors: M
authors: Gupta
authors: Department of Anesthesia, ESI PGIMSR, Basaidarapur, New Delhi, India.
authors: Iti
authors: I
authors: Shri
authors: Department of Anesthesia, ESI PGIMSR, Basaidarapur, New Delhi, India.
authors: Prashant
authors: P
authors: Sakia
authors: Department of Anesthesia, ESI PGIMSR, Basaidarapur, New Delhi, India.
authors: Deepika
authors: D
authors: Govil
keywords: Bispectral monitoring; cardiostability; isoflurane; mean alveolar concentration; sevoflurane