CORRELATION OF BIS INDEX WITH SEVOFLURANE CONCENTRATION IN PAEDIATRIC ANAESTHESIA

Abstract

Objectives: To correlate BIS value with anaesthetic concentration of sevoflurane during various phases of conventional anaesthesia in children and to compare end-tidal with alveolar concentration of Sevoflurane on Gasman.

Methods and Material: It is a prospective single blind study conducted in 25 ASA-I and II paediatric patients of either sex between 2 to 12 years of age posted for general surgical procedures. Anaesthesia was conducted in conventional manner by consultant who was blinded for BIS value and Sevoflurane concentration. Same cases were compared on Gasman simulator programme.

Results: BIS value decreased to 71.65±13.5 at the induction and it further reduced to 40 at intubation, it was ranged between 40 and 60 during maintenance phase of anaesthesia. Extubation was done at BIS value of 75. At induction, end-tidal Sevoflurane concentration was 6.41±0.67 which was 7.08±0.69 at intubation. During maintenance, end-tidal concentration was in range of 1.5±0.64 -3.19±0.39 and decreased to 0.14 ±0.27 at extubation. At induction, MAC of Sevoflurane was 3.37±0.34, which was 3.58±0.3 at intubation. During maintenance, MAC was in range of 1.07±0.56 to 1.71±0.28 which decreased to 0.07±0.16 at extubation. End-tidal concentration of conventional method was comparable with alveolar concentration of Gasman simulator.

Conclusions: Correlating BIS value with end tidal Sevoflurane concentration, inverse linear relationship was established and our clinical finding correlates well with Gasman simulator programme.