Human middle cerebral artery flow velocity during controlled hypotension combined with hemodilution-transcranial Doppler study.
OBJECTIVE
To evaluate the effects of controlled hypotension combined with hemodilution on human middle cerebral artery flow velocity (Vmca) by transcranial Doppler ultrasonography.


METHODS
Randomized prospective study.


METHODS
Inpatient surgery at Nagasaki Rosai Hospital.


METHODS
Thirty American Society of Anesthesiologists physical status I and II patients scheduled for total hip arthroplasty.


METHODS
Anesthesia was maintained with nitrous oxide-oxygen (N(2)O-O(2)) and sevoflurane during normocapnia. Hemodilution was carried out after induction of anesthesia, in which blood was withdrawn then replaced with the same amount of hydroxyethyl starch to achieve a final hematocrit level of 32% (group A = mild hemodilution group, N = 15) or 24% (group B = moderate hemodilution group, N = 15). In both groups, controlled hypotension was induced with prostaglandin E(1) to maintain mean arterial pressure at approximately 55 mm Hg for 80 minutes.


RESULTS
Vmca and blood gas were measured before hemodilution, after hemodilution, 80 minutes after starting hypotension, and 60 minutes after recovery from hypotension. Vmca significantly increased in group A (+122%) and group B (+156%) after each hemodilution. In group B, Vmca was significantly greater than baseline values at 80 minutes after starting hypotension (+135%) and 60 minutes after recovery from hypotension (+140%).


CONCLUSIONS
The combination of moderate hemodilution, such as hematocrit value of 24%, and prostaglandin E(1)-induced hypotension would not impair middle cerebral artery flow during sevoflurane-N(2)O-O(2) anesthesia during normocapnia.
Fukusaki
Makoto
M
Department of Anesthesia, Nagasaki Rosai Hospital, Sasebo 857-0134, Japan. fukusaki@na-robyo.jp
Kanaide
Masato
M
Inadomi
Chiaki
C
Yamashita
Kazunori
K
Takada
Masafumi
M
Terao
Yoshiaki
Y
Sumikawa
Koji
K
D000368:Aged; D018685:Anesthetics, Inhalation; D019644:Arthroplasty, Replacement, Hip; D001783:Blood Flow Velocity / Q000502:physiology*; D001784:Blood Gas Analysis; D005260:Female; D006438:Hemodilution / Q000379:methods*; D006801:Humans; D007023:Hypotension, Controlled / Q000379:methods*; D008297:Male; D008738:Methyl Ethers; D008875:Middle Aged; D020768:Middle Cerebral Artery / Q000000981:diagnostic imaging / Q000502:physiology*; D009609:Nitrous Oxide; D011446:Prospective Studies; D000077149:Sevoflurane; D017585:Ultrasonography, Doppler, Transcranial
D018685:Anesthetics, Inhalation; D008738:Methyl Ethers; D000077149:Sevoflurane; D009609:Nitrous Oxide