[The problem of airtightness during the use of a laryngeal mask under conditions of carboperitoneum and muscle relaxation].

This study was aimed at assessing the airtightness of the airways during the use of a laryngeal mask (LM) under conditions of myoplegia and traditional forced ventilation of the lungs (FVL) with carboperitoneum (CP) during laparoscopic cholecystectomy (LCE). A total of 146 anesthesias for LCE were carried out using LM (n = 86) or endotracheal tube (ETT) (n = 60). The groups did not differ by the demographic characteristics or concomitant diseases. After premedication and induction of anesthesia it was maintained with N2O:O2--2/1 (Fi O2 = 0.3), fractionated administration of fentanyl (0.1-0.2 mg), and pipecuronium bromide (0.06 mg/kg). A gastric tube was inserted. Two variants of FVL were used: 1) permanent minute respiration volume (MRV) was maintained and 2) MRV was increased in order to maintain the Et CO2 at a constant level. The amount of gastric contents was measured and its pH assessed. Regurgitation and aspiration was assessed (in 33 patients) using methylene blue in gelatin capsules administered orally 10 min before anesthesia. Gas exchange was monitored by the Datex Capnomac-Ultima and by check-ups of acid base balance in the arterial capillary blood, hemodynamics was monitored by noninvasive Criticon Dynamap monitor. Manual FVL with inhalation P no more than 10 cm H2O completely prevented the entry of gas narcotic mixture into the stomach. Application of LM under conditions of total myoplegia and FVL with inhalation P of 23-25 cm H2O provided a satisfactory airtightness of the LM-airways contact without audible (appreciable) leaking of gas narcotic mixture. Leakage of gas narcotic mixture during LM application under total myoplegia and carboperitoneum (with CO2 pressure in the abdominal cavity 12 cm Hg) is no more than 6%, which indicates that LM is a reliable air guide providing good airtightness of the LM-airways contact even under conditions of increased abdominal pressure. No cases of regurgitation and aspiration were observed.