"comparison of hemodynamic changes after insertion of laryngeal mask airway, facemask and endotracheal intubation"

hemodynamic changes are major hazards of general anesthesia and are probably generated by direct laryngoscopy and endotracheal intubation. we designed this prospective randomised study to assess the cardiovascular changes after either laryngeal mask airway (lma), face mask (fm) or endotracheal tube (ett) insertion in the airway management of adult patients anesthetised with nitrous oxide and halothane. a total of 195 healthy normotensive adult patients with normal airways were randomly assigned to one of the three groups according to their airway management (n= 65 each) for transurethral lithotripsy procedures. heart rate (hr), systolic blood pressure (sbp), diastolic blood pressure (dbp) and mean arterial blood pressure (map) values were recorded before the induction of anesthesia, and then every three minutes until 30 min thereafter. the mean maximum hr and map values obtained during 15 and 30 minutes after insertion of lma were 81±13, 73±8 bpm and 82±14, 79 ±11 mmhg, respectively which were significantly smaller compared to those with fm (84±12, 80±6 bpm and 86±10, 83±13 mmhg) and ett (96±8, 88±7 bpm and 91±11, 82±9 mmhg) (p< 0.05). direct stimulation of the trachea appears to be a major cause of the hemodynamic changes associated with tracheal intubation during general anesthesia, but why hemodynamic changes in lma were smaller than facemask needs further study. in healthy normotensive patients the use of lma for the airway management during general anesthesia results in a smaller cardiovascular change than fm and ett.