Autonomic activity during desflurane anesthesia in patients with brain tumors.
OBJECTIVE
Although intracranial tumors may affect autonomic function, there are few reports of autonomic changes during anesthesia. The purpose of this study was to evaluate autonomic effects of anesthesia in patients with brain tumors compared to neurosurgical controls.


METHODS
Two groups were evaluated: group 1 = 10 neurosurgical patients undergoing spinal cord surgery, group 2 = 10 patients with intracranial tumors. After placement of electrocardiogram and Response Entropy electroencephalogram (EEG) electrodes, 10 min baseline measures were made. Heart periods were transformed into a percentage index and heart rate entropy determined as a measure of variance of autonomic activity. Tone was evaluated as the balance between accelerator and inhibitory activity. Tone-entropy was measured during propofol anesthetic induction and the first 60 min of desflurane anesthesia before the start of surgery.


RESULTS
Blood pressure and heart rate were similar between the groups. Starting at awake levels, vagal heart tone was observed. Anesthesia decreased vagal dominance to near zero in both groups. Heart rate entropy and EEG activity decreased during anesthesia with no significant difference between the groups. Desflurane concentrations required to maintain anesthesia were significantly lower in patients in brain tumors.


CONCLUSIONS
Tone-entropy analysis of heart rate indicates anesthetic related depression of autonomic activity with no difference between groups. Normal titration of desflurane concentrations to maintain adequate blood pressure produced desflurane requirements that were lower in patients with brain tumors, while autonomic and EEG activity were similar.
Paisansathan
Chanannait
C
Department of Anesthesiology, University of Illinois at Chicago, 1740 W Taylor, Suite 3200, Chicago, IL 60612, USA. oon@uic.edu
Hoffman
William E
WE
Lee
Michael
M
Ananda
Ranga C
RC
Wheeler
Peggy
P
D000328:Adult; D000368:Aged; D000769:Anesthesia, Inhalation / Q000009:adverse effects; D018685:Anesthetics, Inhalation / Q000008:administration & dosage*; D001341:Autonomic Nervous System / Q000187:drug effects* / Q000503:physiopathology*; D001794:Blood Pressure / Q000187:drug effects; D001932:Brain Neoplasms / Q000503:physiopathology* / Q000601:surgery; D016022:Case-Control Studies; D000077335:Desflurane; D004569:Electroencephalography; D006339:Heart Rate / Q000187:drug effects; D006801:Humans; D007530:Isoflurane / Q000008:administration & dosage / Q000031:analogs & derivatives*; D008875:Middle Aged
D018685:Anesthetics, Inhalation; D000077335:Desflurane; D007530:Isoflurane