VENTILATORY PARAMETERS IN CHILDREN DURING PROPOFOL ANESTHESIA - A COMPARISON WITH HALOTHANE

Purpose: The purpose of this study was to compare the effects of propo fol on ventilation with those of halothane. Methods: Respiration was s tudied in 20 spontaneously breathing children undergoing elective dent al restoration randomized to receive either propofol (Group P) or halo thane (Group H) anaesthesia; Data were recorded at different inspired concentrations of halothane (FIH) or propofol (RivP) during a washout of the anaesthetic agent. The FIH 2%, 1% and 0% corresponded to an end -tidal halothane concentration of 1.38 +/- 0.06%, 0.857 +/- 0.03% and 0.191 +/- 0.01% respectively. The RivP were 18, 15, 12, 9 and 0 mg . k g(-1). hr(-1). The inspiratory flow waveform, the CO2 waveform and the occluded inspiratory pressure waveform were recorded. The flow wavefo rm was analyzed for minute ventilation (Pi), and tidal volume (VT), pa rameters of breath Timing [Total time (Ttot), Inspiratory time (Ti)]an d parameters of breath Amplitude [mean inspiratory flow (VT/Ti)]. The slope of the initial 100 msec (dP/dt(0.1)) of an occluded inspiration, together with the occluded inspiratory time (Ti-occ) and the ratio of the occluded to unoccluded inspiratory time (T-iocc/Ti) were obtained Results: There were intergroup differences in the preemergence values of Ttot, dP/dt(0.1) and Ti-occ/Ti. In group P the Vi, VT and Ttot inc reased and PETCO(2) decreased during a washout of propofol. The values of dP/dt(0.1), in Group P at all RivP were half the values of those i n Group H. The ratio Ti-occ/Ti did not change in Group P and increased in Group H during a washout of halothane. Conclusion: Propofol anaest hesia was associated with a decrease in Pi whereas during halothane an aesthesia, Pi did not change. Ventilation in Group P differed from Gro up H in parameters of both breath Drive and Timing.