[Breathing pattern and postoperative analgesia at various effect-site concentrations of fentanyl].
BACKGROUND
We investigated how various effectsite concentrations of fentanyl could affect breathing pattern and postoperative analgesia.


METHODS
This study enrolled 64 ASA physical status 1 and 2 patients, undergoing elective surgical procedures, including otologic, orthopedic, breast surgery and gynecological laparoscopic procedure. General anesthesia was performed with sevoflurane inhalation and target-controlled infusion for fentanyl. After the surgery, fentanyl was administered by a target-controlled infusion system to maintain one of the effect-site concentrations of fentanyl as follows ; 0.5, 0.8, 1.0, 1.2, 1.5, 1.8 and 2.0 ng x ml(-1) under 0.8% of the end-tidal sevoflurane concentration. We recorded spontaneous respiratory rate (RR), tidal volume (Vt), and minute volume (MV). After sevoflurane inhalation was finished, the end-tidal sevoflurane concentration at the time at which they responded to command was recorded. Postoperative pain was assessed right after extubation.


RESULTS
Although RR decreased in a effect-site concentration of fentanyl dependent manner, V(T) increased gradually, resulting in relatively constant range between 0.5-2.0 ng x ml(-1) of effect-site concentration of fentanyl. Postoperative pain was adequately controlled in the range between 1.2-2.0 ng x ml(-1) of effect-site concentrations of fentanyl.


CONCLUSIONS
According to our data, 1.2-2.0 ng x ml(-1) of effect-site concentration of fentanyl could provide adequate postoperative analgesia without respiratory depression in otologic, orthopedic, breast surgery and gynecological laparoscopic procedures.
Noguchi
Nobuhiro
N
Department of Anesthesiology, Faculty of Medicine, University of the Ryukyus, Okinawa 903-0215.
Kamizato
Kota
K
Fuchibe
Makoto
M
Miyata
Yuji
Y
Kakinohana
Manabu
M
Nagata
Osamu
O
Sugahara
Kazuhiro
K
D000328:Adult; D000768:Anesthesia, General; D018686:Anesthetics, Intravenous / Q000008:administration & dosage* / Q000378:metabolism*; D017558:Elective Surgical Procedures; D005260:Female; D005283:Fentanyl / Q000008:administration & dosage* / Q000378:metabolism*; D006801:Humans; D008297:Male; D010149:Postoperative Pain / Q000517:prevention & control*; D012119:Respiration
D018686:Anesthetics, Intravenous; D005283:Fentanyl