[Efficacy and safety of remifentanil-based regimen for postoperative pain management in abdominal surgery patients: a double-blind study with low-dose remifentanil infusion of 0.02 microg x kg(-1) x min(-1)].

BACKGROUND: Remifentanil is a powerful analgesic with fast onset and ultra-short duration of action. Its context-sensitive half-time is consistently short even after a prolonged infusion. Remifentanil is effective for providing better postoperative analgesia, but this method is not generally accepted in Japan. The present study was conducted to document efficacy and safety of low-dose remifentanil infusion in postoperative patients. METHODS: Forty patients undergoing abdominal surgery were studied prospectively. They were randomly assigned to either remifentanil (0.02 microg x kg(-1) x min(-1)) or placebo group. Postoperatively all patients received continuous epidural anesthesia with lidocaine and IV patient-controlled analgesia with fentanyl. Flurbiprofen was administered only when no pain relief was achieved. Visual analogue scale (VAS), requirement of fentanyl and flurbiprofen, and the incidence of remifentanil-related adverse effects (respiratory depression, nausea, vomiting, pruritus) were examined at 3 hourly intervals for 12 hours. RESULTS: There are no statistical differences between two groups in pain scores. No adverse events including respiratory depression occurred throughout the study in both groups. CONCLUSIONS: Remifentanil infusion at 0.02 microg x kg(-1) x min(-1) can safely be used without any serious adverse events, while it may not be enough for postoperative analgesia. The best dosage of this drug for postoperative analgesia remains to be elucidated.

[Intraperitoneal irrigation for pseudomyxoma peritonei-a case of critical metabolic alkalosis precipitated by irrigation with 101 of sodium bicarbonate--].

Pseudomyxoma peritonei causes marked accumulation of jelly-like ascites in the peritoneal cavity. Removal of much mucinous ascites by irrigating the cavity appears to be an effective treatment. We describe a patient who underwent the irrigation with sodium bicarbonate solution and developed critical alkalemia. A 68-year-old woman with normal renal function was operated on for recurrent pseudomyxoma peritonei. Fol- lowing the excision of primary lesion, her intraperitoneal cavity was irrigated with 10 1 of 7% sodium bicarbonate in about 45 minutes. Thirty minutes after irrigation, blood gas analysis revealed severe metabolic alkalosis (pH 7.714, BE 25.6 mmol x l-1 ) with electrolyte disorder (Na 157.8 mmol x l-1 K 2.31mmol x l-1, Ca 0.73 mmol x l-1). Hypotension (<60 mmHg) and sinus tachycardia (>130 beats x min -1) supervened 75 minutes later. Transferring to the ICU, she was given KC1 solution intravenously based on serial blood analysis while on mechanical ventilation. The next day acid-base disturbance returned spontaneously to normal (pH 7.45, BE 8.0mmol x l-1), leading to endotracheal extubation. Electrolyte imbalance was gradually resolved on 2nd POD and she was discharged from the ICU. Intraperitoneal irrigation with sodium bicarbonate requires special perioperative considerations for lifethreatening alkalemia, especially in a patient with renal impairment.

[The evaluation of total body water composition during caesarean section under spinal anesthesia].

BACKGROUND: Hypotension is a common adverse effect of spinal anesthesia (SA). Preoperative fluid infusion is recommended to prevent hypotension during caesarean section. The aim of this study is to document relationship between preoperative total body water (TBW) and the amount of the vasopressors given intraoperatively and to evaluate the change of maternal body water composition (BWC). METHODS: In 57 patients scheduled for caesarean section under SA, maternal BWC was measured by bioelectrical impedance analysis method. SA was performed using 0.5% isobaric bupivacaine 2 ml and fentanyl 20 microg at L3-4 intervertebral space. After this procedure, the impedance was measured again. We investigated the correlation between TBW and the amount of the vasopressor and the change of maternal BWC before and after SA. RESULTS: No positive linear correlation existed between the preoperative TBW and the amount of vasopressors given intraoperatively. SA produced a 3.8% increase in TBW and a 4.7% increase in extracellular water (ECW, P < 0.01). CONCLUSIONS: Preoperative TBW does not affect the amount of vasopressors given during caesarean section, which suggested massive fluid infusion can not always prevent hypotension after SA. A slight changes in TBW and ECW may be induced by SA, while the exact physiological and clinical significance of these observation remains to be elucidated.