Cardiovascular responses to endotracheal intubation with the Bullard and the Macintosh laryngoscopes

To the Editor: Since the Bullard laryngoscope (BL) is anatomically shaped, it is considered less invasive than the Macintosh laryngoscope (ML) is. We compared cardiovascular changes following endotracheal intubation and times required for intubation between the two laryngoscopes. After obtaining Institutional approval and informed consent, 30 patients without hypertension were studied. Endotracheal intubation was performed by BL (15 patients) or ML (15 patients), following induction of general anesthesia. Systolic and diastolic blood pressure (SBP and DBP), heart rate just before and one, two, three, four and five minutes after intubation were measured. The time required to visualize the glottis (T1), to place the tube (T2), and to complete intubation (T3) were recorded. All intubations were successful at the first attempt. The increase in SBP displayed a tendency to be smaller in the Bullard group than in the Macintosh group (12 mmHg difference, two minutes after intubation), but the difference was not statistically significant (Figure). There were no differences in DBP and in heart rate between the groups. Time to visualize the vocal cords, time required to place the endotracheal tube and time to complete intubation were significantly longer with the BL (7.7, 17.5 and 21.3 sec, respectively) than with the ML (5.3, 12.7 and 14.7 sec, respectively; P < 0.05). Although the time to complete intubation with the BL was statistically longer, the 6.6 sec difference does not seem clinically important. Although we were unable to demonstrate that the BL is less invasive in patients without hypertension, further studies (larger sample size; hypertensive patients) appear warranted.