soda-lime and Carbon-Monoxide-Poisoning

After institutional approval, we studied the effect of animal size, anesthetic concentration, and fresh gas flow (FGF) rate on inspired carbon monoxide (CO) and carboxyhemoglobin (COHb) during anesthesia in swine, using soda lime previously dried to 1 +/- 0.1% water content. To ascertain the effect of anesthesia, eight adult pigs were anesthetized with either 1 minimum alveolar anesthetic concentration (MAC) desflurane or isoflurane and, to characterize the effect of the FGF rate, it was doubled in four pigs. To determine the effect of animal size, four small and four large pigs received 1 MAC desflurane or isoflurane, and to determine the effect of the anesthetic concentration, a group of four swine was exposed to 0.5 MAC. CO and COHb concentrations were larger with desflurane (5500 +/- 980 ppm and 57.90% +/- 0.50%, respectively) than with isoflurane (800 ppm and 17.8% +/- 2.14%, respectively), especially in the small animals. Increasing the FGF rate significantly reduced peak CO and COHb concentrations resulting from both anesthetics; however, when each anesthetic was reduced to 0.5 MAC, the concentrations obtained were similar. We conclude that CO intoxication is more severe with desflurane than with isoflurane, that small animals are at higher risk for CO poisoning, and that low FGF can increase COHb concentrations.. The present study shows that the use of desflurane with desiccated carbon dioxide absorbents in pediatric anesthesia can produce a dangerous carbon dioxide intoxication, especially with low-flow anesthesia.

Topics: Absorption; Air; Anesthesia, Closed-Circuit; Anesthetics, Inhalation; Animals; Body Constitution; Body Weight; Calcium Compounds; Carbon Monoxide; Carbon Monoxide Poisoning; Carboxyhemoglobin; Desflurane; Inhalation; Isoflurane; Oxides; Rheology; Risk Factors; Sodium Hydroxide; Swine

Topics: Adolescent; Adult; Anesthesia; Anesthetics, Inhalation; Calcium Compounds; Carbon Monoxide Poisoning; Carboxyhemoglobin; Child; Child, Preschool; Desflurane; Drug Interactions; Humans; Isoflurane; Oxides; Sodium Hydroxide

Topics: Absorption; Anesthetics, Inhalation; Barium Compounds; Calcium Compounds; Calcium Hydroxide; Carbon Monoxide; Carbon Monoxide Poisoning; Humans; Humidity; Hydrocarbons, Halogenated; Intraoperative Complications; Oxides; Potassium Compounds; Risk; Sodium Hydroxide

After reports of carbon monoxide toxicity from the United States, the Medicines Control Agency issued a warning which recommended that soda lime used in circle breathing systems should not be allowed to dry out. We have measured carbon monoxide levels within a circle system in vitro (under a variety of conditions) and in vivo. Carbon monoxide was detected only when a patient was connected to the circle system. As levels in the expiratory limb of the circle system were significantly higher than those in the inspiratory limb, we conclude that the patient acts as the source of carbon monoxide.

Topics: Anesthesiology; Anesthetics, Inhalation; Calcium Compounds; Carbon Dioxide; Carbon Monoxide; Carbon Monoxide Poisoning; Humans; Nitrous Oxide; Oxides; Smoking; Sodium Hydroxide

Topics: Anesthesiology; Anesthetics, Inhalation; Calcium Compounds; Carbon Monoxide; Carbon Monoxide Poisoning; Humans; Intraoperative Complications; Oxides; Risk Factors; Sodium Hydroxide

Topics: Anesthesia, General; Anesthesiology; Anesthetics, Inhalation; Calcium Compounds; Carbon Monoxide Poisoning; Desflurane; Female; Humans; Intraoperative Complications; Isoflurane; Middle Aged; Oxides; Sodium Hydroxide

Topics: Aged; Anesthesia, General; Anesthesiology; Anesthetics, Inhalation; Calcium Compounds; Carbon Monoxide Poisoning; Female; Humans; Intraoperative Complications; Oxides; Sodium Hydroxide