Effect of partial pressure on solubility of isoflurane in blood.

The effect of partial pressure of isoflurane on its solubility in blood of different haematocrit was determined at different isoflurane partial pressures, using a syringe--flask method and gas chromatography with blood from one donor. The solubility of isoflurane decreased with increasing blood haematocrit (39.5%, 51.9% and 61.9%) and isoflurane partial pressure from 1 MAC to 4 MAC. The solubility in 50% and 60% haematocrit blood at 2, 3 and 4 MAC was significantly different from the solubility in normal blood at 1 MAC (P < 0.05). We conclude that the solution of isoflurane in blood (especially in high haematocrit blood) does not obey Henry's law.

Combined traditional Chinese medicine and Western medicine. Relieving effects of Chinese herbs, ear-acupuncture and epidural morphine on postoperative pain in liver cancer.

In the evaluation of Chinese herbs (A), ear-acupuncture (B) and epidural morphine (C) to relieve postoperative pain and abdominal distension, sixteen male patients with primary liver cancer were observed. This study was conducted by means of orthogonal experiment and double blind, randomized design. The patients received various treatments according to the display of the orthogonal table L16(2)15 which corresponds to 2(3) factorial experiment design. C+ (morphine 2 mg) was given before the peritoneum was sutured. A+ (orally administered) and B+ were given 24 hours after operation. 50-100 mg of pethidine was given when the pain intensity VAS (0-100) exceeded 50-70. The observation parameters included plasma leucine enkephalin (LEK), postoperative total dosage of narcotics administered for 5 days, VAS for pain and pain reliever, abdominal distension, urinary retention, constipation, etc. The results were as follows: a. Patients who had received A (A+B+C+, A+B+C-, A+B-C-, A+B-C+); C (C+A+B+, C+A+B-, C+A-B+, C+A-B-), or B (B+A+C+, B+A+C-, B+A-C+, B+A-C-) produced better analgesic effects than those who had received placebo. The A, B, and C reduced narcotics 650, 450 and 550 mg respectively when compared with placebo. The effects of A and C were of statistical significance (P < 0.05), while AB, BC, and AC interactions were not found; b. A and B minimized abdominal distension and urinary retention, while C prolonged them. As compared with the placebo, A and B accelerated restoration of bowel peristalsis (P < 0.05, ANOVA). Both A and B decreased it for 165 hours, while epidural morphine prolonged it for 49 hours; and c.(ABSTRACT TRUNCATED AT 250 WORDS)

Nitrous oxide decreases solubility of isoflurane and halothane in blood.

This study investigated the effects of carrier gases on the solubility of isoflurane or halothane in blood. The blood/gas partition coefficients (lambda blood/gas) of 1 minimum alveolar anesthetic concentration of isoflurane or halothane in 100% oxygen, 30% oxygen with 70% nitrous oxide, 100% nitrous oxide or air were measured at 37 degrees C, with blood from four donors. The values of isoflurane or halothane in 100% nitrous oxide (1.42 +/- 0.03; 2.59 +/- 0.05) were lower (P < 0.05) than those obtained when using 100% oxygen (1.53 +/- 0.02; 2.71 +/- 0.05) or air (1.54 +/- 0.03; 2.74 +/- 0.05). To determine the effect of absence of oxygen in the blood containing nitrous oxide on solubility, lambda blood/gas of 1 minimum alveolar anesthetic concentration of isoflurane or halothane in 100% oxygen, a gas mixture (30% oxygen and 70% nitrous oxide) or 100% nitrous oxide were measured under the same conditions. The values of isoflurane or halothane in 100% nitrous oxide (1.29 +/- 0.03; 2.25 +/- 0.08) and in a gas mixture of 30% oxygen and 70% nitrous oxide (1.33 +/- 0.04; 2.29 +/- 0.05) were lower (P < 0.05) than those obtained with 100% oxygen (1.40 +/- 0.03; 2.37 +/- 0.04). We conclude that nitrous oxide decreases the lambda blood/gas of isoflurane or halothane, and that this change of solubility, although small, increases the uptake rate of halothane or isoflurane.