Halothane: how should it be used in a developing country?

The anaesthetic agent halothane is still widely used in developing countries including the Islamic Republic of Iran because of its low price. Because of halothane-induced hepatitis, a rare complication, it has been replaced by other inhalation anaesthetics in Western countries; it has been suggested by some Iranian professionals that the Islamic Republic of Iran should do the same. We evaluated various dimensions of this replacement through a literature review to assess the incidence of halothane-induced hepatitis and costs of anaesthetics in the country. We also conducted a questionnaire survey of 30 anaesthesiology/gastroenterology experts about their views on the subject. The results indicate that the incidence of halothane hepatitis in the Islamic Republic of Iran is very low and could mostly be avoided by strict adherence to guidelines. Complete withdrawal of halothane in the Islamic Republic of Iran might not be appropriate at present. Comprehensive cost-effectiveness studies are needed before a decision is made on complete replacement of halothane with other anaesthetics.

[Pollution of operating rooms. Measurements made during five anesthesias]. / Pollution des blocs opératoires. Measures effectuées lors de cinq anesthésies.

The purpose of this study is to measure amounts of anaesthetic vapours present in operating rooms and anaesthetic places without any gas scavenging system except air conditioning with fifteen air changes per hour. Nitrous oxide, halothane and isoflurane were measured. Halothane and isoflurane concentration is slightly higher than the French standard for anaesthetic places and lower for operating rooms. Nitrous oxide concentration is five to eight times greater than recommended standard. Although no international agreement exists concerning an acceptable pollution standard, it seems that only nitrous oxide pollution is disquieting. It would seem sensible to avoid needles contamination by use of waste gas scavenging devices.

The nonlinear potency of sub-MAC concentrations of nitrous oxide in decreasing the anesthetic requirement of enflurane, halothane, and isoflurane in rats.

The effect of nitrous oxide (N2O) on the MAC of enflurane, halothane, and isoflurane was determined in male rats. Each rat received either enflurane, halothane, or isoflurane, along with 0%, 15%, or 75% N2O. Anesthetic equilibration was verified by mass spectrometry sampling of end-tidal gases. MAC was determined at each N2O concentration by the standard tail clamp method. The N2O dose-response data for each animal were fit by a second-order polynomial equation to estimate the value of a second-order coefficient. A linear dose-response would result in a value of zero, whereas the extent to which the data deviate from nonlinearity would be reflected by an increase in the value of this coefficient. The null hypothesis, that the second-order coefficient should be zero, was tested by a one-sample two-tailed t test. The volatile anesthetic requirement decreased as the N2O concentration increased; however, it did not do so linearly. For each of the three volatile anesthetic groups, the second-order coefficients were consistently greater than zero (P less than 0.05). These data are not consistent with the accepted presumption that the summation of N2O with volatile anesthetics is linear.

Concentration of halothane in veterinary operating and treatment rooms.

Fourteen operating rooms and 3 treatment rooms in veterinary facilities were monitored for ambient halothane. All rooms except 1 were in private practices, Regularly scheduled surgical or dental procedures were monitored under routine working situations of each facility. The mean maximal steady halothane value for all rooms was 4.7 ppm, with a range of 1.1. to 18 ppm. In 10 of the 17 rooms, concentrations exceeded the recommended maximum of 2 ppm. Rooms that had scavenging devices averaged 1.4 ppm whereas rooms without scavenging devices averaged 5.2 ppm. The average room volume for the 17 rooms was 39.7 m3, with a range of 21.6 to 79 m3. The average ventilation or air movement for 11 rooms was 6 rooms air exchanges/hour. The average time spent in the rooms during halothane usage was 1.8 hours.