Effects of sevoflurane and propofol on pulmonary shunt fraction during one-lung ventilation for thoracic surgery.

Forty patients requiring one-lung ventilation (OLV) for thoracic surgery were randomly assigned to receive propofol (4-6 mg kg(-1) h(-1)) or sevoflurane (1 MAC) for maintenance of anaesthesia. Three sets of measurements were taken: (i) after 30 min of two-lung ventilation (TLV), (ii) after 30 min of one-lung ventilation (OLV-1) in the supine position and (iii) during OLV in the lateral position (OLV-2) with the chest open and before surgical manipulation of the lung. There were no differences between groups in patient characteristics or preoperative condition. Increases in shunt fraction during OLV-1 were 17.4% and 17.2% (P=0.94), those during OLV-2 were 18.3% and 16.5% (P=0.59) for the propofol and sevoflurane group, respectively. Cardiac index and other haemodynamic and respiratory variables were similar for the two groups. We conclude that inhibition of hypoxic pulmonary vasoconstriction by sevoflurane may only account for small increases in shunt fraction and that much of the overall shunt fraction during OLV has other causes.

A randomized controlled double-blind trial comparing piritramide and morphine for analgesia after hysterectomy.

BACKGROUND AND OBJECTIVE: Efficacy and side-effects of piritramide (pirinitramide) and morphine, given intravenously for postoperative analgesia after hysterectomy, were compared in a randomized controlled double-blind trial in 92 ASA class I-III patients. METHODS: Administration was investigator-controlled during the first 90 min and subsequently via a patient-controlled device. Visual analogue scales for pain intensity and verbal rating scales for side-effects were taken repeatedly. RESULTS: Median visual analogue scores for pain intensity on a 100-mm scale 4, 8 and 24 h after surgery were 10, 8.5 and 5 mm in the piritramide group and 18, 10 and 8.5 mm in the morphine group. These differences are neither statistically nor clinically significant. Median values for nausea on a verbal rating scale from 0 to 3 were zero for both groups at all times with similar ranges. There was no difference in number of episodes of vomiting and retching and usage of antiemetics. The mean amount of piritramide used for initial titration was 15.2 mg; the respective amount of morphine was 15.4 mg. CONCLUSIONS: In this setting the two agents are equally effective and show a similar profile of side-effects.

The pharmacokinetics and analgesic efficacy of larger dose rectal acetaminophen (40 mg/kg) in adults: a double-blinded, randomized study.

UNLABELLED: Analgesic acetaminophen plasma concentrations are not known. We investigated in a randomized, double-blinded study the pharmacokinetics and analgesic efficacy of small- (AS; 20 mg. kg(-1)) and larger- (AL; 40 mg/kg) dose rectal acetaminophen and compared it with the combination (C) of rectal diclofenac (100 mg) and acetaminophen (20 mg/kg) in 65 women undergoing hysterectomy. Suppositories were administered after the induction of a standardized general anesthesia. Pain (measured by using a 10-cm visual analog scale) and morphine consumption (patient-controlled analgesia) were repeatedly assessed for 24 h. Acetaminophen plasma concentrations were measured by using a fluorescence polarization immunoassay. Antipyretic plasma concentrations (10-20 mg/L) after 40 mg/kg acetaminophen were not associated with improved analgesia or decreased opioid requirements; 20 mg/kg acetaminophen produced subtherapeutic plasma levels (<10 mg/L). Maximal plasma concentrations of 17.2 and 10.4 mg/L (P < 0.01, analysis of variance) were achieved after 4.2 and 3.6 h for the AL and AS groups, respectively. The only difference in clinical outcome was lower visual analog scale scores after acetaminophen/diclofenac (C 2.0 versus AS 3.2 and AL 3.4) 4 h after the induction (P < 0.05, analysis of variance). Acetaminophen pharmacokinetics in adults were similar to those observed in children. Analgesic plasma concentrations are likely to be higher than antipyretic plasma levels, which were only attained after twice the recommended rectal dose was administered. Analgesic plasma concentrations have yet to be determined but may be higher than those associated with antipyresis. IMPLICATIONS: Acetaminophen pharmacokinetics were comparable in adults and children. Plasma concentrations known to reduce fever did not produce better pain relief and were only achieved after twice the conventional dose was administered. Analgesic plasma concentrations have yet to be determined but may be higher than those associated with antipyresis.