Skin conductance monitoring compared with Bispectral Index to assess emergence from total i.v. anaesthesia using propofol and remifentanil.
BACKGROUND
Arousal after sevoflurane anaesthesia has been detectable by monitoring changes in skin conductance (SC) with similar accuracy as monitoring Bispectral Index (BIS). As SC monitoring detects changes in sympathetic tone, the measurements might be confounded by the sympatholytic properties of propofol, a component of total i.v. anaesthesia (TIVA). Therefore in this study, monitoring of SC during emergence from TIVA was compared with the monitoring of BIS.


METHODS
Twenty-five patients undergoing plastic surgery were investigated. The number of fluctuations of SC per second (NFSC), BIS and haemodynamic variables [systolic blood pressure (SBP) and heart rate (HR)] were recorded simultaneously. The performance of the monitoring devices in distinguishing between the clinical states 'steady-state anaesthesia', 'first clinical reaction' and 'extubation' were compared using the method of prediction probability (Pk) calculation.


RESULTS
BIS((R)) showed the best performance in distinguishing between 'steady-state anaesthesia' and 'first reaction' (Pk BIS 0.99 vs NFSC 0.80; P<0.01), and 'steady-state anaesthesia' and 'extubation' (Pk BIS) 1.00 vs NFSC 0.91; P<0.05); the time from first change of BIS or NFSC to a first clinical reaction was significantly longer for NFSC (median BIS 135 s vs NFSC 191 s; P<0.05). BIS and NFSC performed better in distinguishing between the investigated clinical states than SBP and HR.


CONCLUSIONS
In this study, BIS was found to predict arousal with a higher probability but slower response times than NFSC in patients waking after TIVA.
Ledowski
T
T
Department of Anaesthesia and Pain Medicine, Royal Perth Hospital Wellington Street Campus, Perth WA 6000, Australia. thomas.ledowski@health.wa.gov.au
Bromilow
J
J
Paech
M J
MJ
Storm
H
H
Hacking
R
R
Schug
S A
SA
D000328:Adult; D000762:Anesthesia Recovery Period; D019162:Anesthetics, Combined / Q000494:pharmacology; D018686:Anesthetics, Intravenous / Q000494:pharmacology*; D001794:Blood Pressure / Q000187:drug effects; D004569:Electroencephalography / Q000187:drug effects*; D005260:Female; D005712:Galvanic Skin Response / Q000187:drug effects*; D006339:Heart Rate / Q000187:drug effects; D006801:Humans; D008297:Male; D008875:Middle Aged; D008991:Monitoring, Physiologic / Q000379:methods; D010880:Piperidines / Q000494:pharmacology*; D015742:Propofol / Q000494:pharmacology*; D011930:Reaction Time / Q000187:drug effects; D019651:Plastic Surgery Procedures; D000077208:Remifentanil
D019162:Anesthetics, Combined; D018686:Anesthetics, Intravenous; D010880:Piperidines; D000077208:Remifentanil; D015742:Propofol