BIS - AAI and clinical measures during propofol target controlled infusion with Schnider's pharmacokinetic model.
OBJECTIVE
The A-line autoregressive index (AAI) and the Bispectral Index Score (BIS) are two commercially available indexes of anesthetic depth widely used in clinical practice. The aim of the current study was to compare the accuracy of AAI, BIS, Schnider's predicted effect-site concentration of propofol (Ce propofol) to assess depth of anesthesia.


METHODS
Forty-four patients scheduled for major elective abdominal surgery received target effect-site controlled infusion of propofol. Target effect-site (Ce propofol) was started at 1.5 mug/mL and increased every 4 min by 1.0 microg/mL until 5.5 microg/mL were achieved. At every step sedation level was estimated, using AAI, BIS, Observer's Assessment of Alertness/Sedation scale (OAA/S), loss of eyelash reflex and Ce propofol.


RESULTS
We enrolled 44 patients, 20 males and 24 females, ASA I/II 18/26, 48+/-10 years, 68.2+/-9 kg, 165+/-7.1 cm, body mass index (BMI) 25+/-3.5. At increasing Ce propofol BIS-AAI values decreased progressively (BIS range 97-38) (AAI range 97-17). Values of BIS < or = 50, of AAI < or = 48 and of Ce propofol > or = 5.1 resulted in OAA/S=0, while values of BIS < or = 62, AAI < or = 53 and Ce propofol < or = 3.5 resulted in OAA/S=2. Loss of eyelash reflex occurred when values were BIS < or = 64 and AAI < or 61.


CONCLUSIONS
BIS, AAI, propofol site effect concentration revealed information on sedation level and consciousness but no gold standard yet exists because of consistent overlap between ''conscious'' and ''not conscious'' states.
Iannuzzi
E
E
Department of Anesthesiological, Surgical and Emergency Sciences, Unit of Anesthesia and Intensive Care Medicine 2nd Service of Anaesthesia, 2nd University of Naples, Naples, Italy.
Iannuzzi
M
M
Viola
G
G
Sidro
L
L
Cardinale
A
A
Chiefari
M
M
D000161:Acoustic Stimulation; D000328:Adult; D000771:Anesthesia, Intravenous; D018686:Anesthetics, Intravenous / Q000009:adverse effects; D004569:Electroencephalography / Q000187:drug effects*; D005072:Evoked Potentials, Auditory / Q000187:drug effects; D005260:Female; D006801:Humans; D016014:Linear Models; D008297:Male; D008875:Middle Aged; D016343:Monitoring, Intraoperative; D015742:Propofol / Q000009:adverse effects
D018686:Anesthetics, Intravenous; D015742:Propofol