Changes in ventilatory patterns during halothane anaesthesia in children.
Changes in ventilatory variables (VE, VE, f, Tl/Ttot, VT/Tl, PE'CO2) were studied in 12 unpremedicated children, weighing between 10 and 20 kg, during halothane anaesthesia. At an inspired concentration of 0.5% halothane, respiratory rate increased, VT decreased, and VE did not change markedly. When the inspired halothane concentration increased further, there was a significant decrease in VE, mainly as a result of a marked decrease in VT. PE'CO2 increased significantly and inspiratory duty cycle decreased at high inspired halothane concentrations. On return to baseline (0.5% halothane), there was a significant decrease in inspiratory timing and a significant increase in PE'CO2. The relations between these changes and the effect of halothane on inspiratory muscles are discussed.
D000769:Anesthesia, Inhalation; D002245:Carbon Dioxide / Q000502:physiology; D002675:Child, Preschool; D006221:Halothane / Q000494:pharmacology*; D006801:Humans; D007223:Infant; D012119:Respiration / Q000187:drug effects*; D013990:Tidal Volume; D013997:Time Factors
D002245:Carbon Dioxide; D006221:Halothane