By Lexa W. Lee
NEW ORLEANS -- October 20, 2009 -- Intraoperative variability measured by Composite Variability Index (CVI) was strongly associated with somatic responses during anaesthesia with either propofol plus remifentanil or sevoflurane plus remifentanil anaesthesia, according to a study presented here October 17 at the 2009 Annual Meeting of the American Society of Anesthesologists (ASA).
The researchers wanted to compare the relation of CVI with somatic responses for propofol/remifentanil and sevoflurane/remifentanil, according to Donald Mathews, MD, St. Vincent's Hospital, New York, New York.
Data analysis was performed on 105 patients who underwent elective, noncardiac surgery. Bispectral index (BIS), surface BIS (sBIS), surface electromyography (sEMG), and CVI were continuously recorded to a computer. Descriptions and times of significant intraoperative events including somatic (ie, movement, grimacing, tearing) and haemodynamic events were recorded.
Anaesthesiologists were blinded to sBIS, sEMG, and CVI at all times. Patients were randomised to receive either remifentanil plus either sevoflurane (group S) or propofol (group P). Sevoflurane and propofol concentrations were adjusted to maintain BIS between 45 and 60 (BIS of 0 = very deep anaesthesia, 100 = awake state).
The maintenance phase of anaesthesia was divided into consecutive 10-minute segments categorised by the absence or presence of a somatic event(s). Mean CVI, sBIS, and sEMG were computed for each segment, excluding all data for 3 minutes following somatic response to allow for variability specifically related to the response.
For each metric, the area under the receiver operating characteristic area under curve (AUC) for discriminating somatic event segments from segments without haemodynamic or somatic events was computed. AUC standard error for each metric and a Z-test was used to compare AUCs of the 2 groups (P < .05 was considered significant).
There was no significant difference in AUCs for CVI and sEMG (group P, 0.76 +- 0.12 vs group S, 0.84 +- 0.12; P = .07 and P, 0.81 +- 0.08 vs S, 0.88 +- 0.08; P = .10). However, the AUC for sBIS was significantly higher in group S than group P (P = .0017).
[Presentation title: CVI Detection of Intraoperative Somatic Events Was Similar With Propofol or Sevoflurane Anesthesia. Abstract A229]
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