The effect of minimal-flow inhalational anesthesia on peak expiratory flow rate

Abstract

Aim: In this study, we aimed to compare the effects of minimal (500 mL/min) and high-flow (3000 mL/min) anesthesia on the respiratory system by evaluating the peak expiratory flow rate (PEFR) and the ventilation pressure. Material and Method: Forty ASA I-II patients undergoing elective middle ear microsurgery under minimal and high-flow desflurane anesthesia were evaluated for the PEFR in the preoperative and the postoperative 1st, 6th, 24th hours. Intraoperative hemodynamic parameters, ventilation pressures and the duration of extubation were also evaluated. Results: There were no significant differences between the groups in terms of demographic characteristics. The duration of operation, anesthesia and extubation, intraoperative peak and plateau pressure, SpO2%, heart rate, end-tidal desflurane, MAC, and FiO2 were similar. In the minimal flow anesthesia group, the MAP (69.40±6.21 mmHg) was significantly higher than in the patients receiving high-flow (61.70±4.39 mmHg) anesthesia (p<0.001). The difference between PEFR values measured at four different time points was statistically significant (time; F (3.38) = 29.696, p<0.001). The PEFR value in the postoperative 1st hour was statistically significantly lower compared to the preoperative levels and the levels measured in the postoperative 6th and 24th hours. The PEFR values of the patients in the high-flow and minimal-flow anesthesia groups were not statistically significantly different (Group; F(1.38) = 0.623, p>0.05). Discussion: The effects of minimal (500 mL/min) and high-flow (3000 mL/min) anesthesia on the respiratory system were compared by PEFR and ventilation pressure showing similar results. With the current technological advances, the use of minimal-flow anesthesia combined with an effective follow-up period may have favorable effects.