[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.
Department of Anesthesiology, Faculty of Medicine, University of the Ryukyus, Okinawa 903-0215.
Nobuhiro
N
Noguchi
Kota
K
Kamizato
Makoto
M
Fuchibe
Yuji
Y
Miyata
Manabu
M
Kakinohana
Osamu
O
Nagata
Kazuhiro
K
Sugahara
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