Opioid sparing during endotracheal intubation using McCoy laryngoscope in neurosurgical patients: the comparison of haemodynamic changes with Macintosh blade in a randomized trial.

BACKGROUND: There is conflicting data in literature to show that the McCoy laryngoscope is less stressful and opioids can actually be avoided during laryngoscopy and intubation with the use of this laryngoscope.

AIM: A comparison of hemodynamic changes with McCoy vs Macintosh laryngoscope..

SETTINGS AND DESIGN: 180 ASA I and II neurosurgical patients undergoing elective surgery for space occupying lesions were recruited. The study was was prospective, randomized and blinded in the setting of neurosurgical perioperative services.

METHODS AND MATERIALS: The patients were divided into four groups (Gr.1 McCoy and fentanyl; Gr. 2 McCoy and no fentanyl; Gr. 3 Macintosh and fentanyl; Gr. 4 Macintosh and no fentanyl). In Gr. 2 and 4 equivalent volume of saline was given in place of fentanyl as placebo. Heart rate, systolic and diastolic blood pressure were measured after laryngoscopy, after intubation and subsequently every minute for the next five minutes. The incidence of cough due to fentanyl treatment was observed.

STATISTICAL ANALYSIS: Haemodynamic changes were compared between and within groups using oneway ANOVA and repeated measures ANOVA. All analysis included 95% CI at 5% significance. The Mann Whitney U test was used for comparing incidence of cough.

RESULTS: No difference was found between McCoy laryngoscopy when done with or without fentanyl pretreatment (HR p=0.848, sys BP p=0.229 and diastolic blood pressure p=0.981). Significant changes in haemodynamic parameters were seen between Macintosh and McCoy laryngoscopy without fentanyl pretreatment (p<0.001) whereas changes were blunted with fentanyl pretreatment in Macintosh laryngoscopy (p<0.05).

CONCLUSIONS: McCoy laryngoscope blade is less stressful and fentanyl pretreatment is not necessary to attenuate haemodynamic responses with its use in ASA I and II patients.