Comparative Evaluation of McGrath MAC, Truview Video Laryngoscopes and Macintosh Laryngoscope for Endotracheal Intubation in Patients Undergoing Surgery under General Anaesthesia.

BACKGROUND

Videolaryngoscopy is a newly developed technique to improve tracheal intubation success. It was made to bypass the need of directly visualising the glottic inlet. These devices are advantageous as there is no need of aligning the laryngeal, pharyngeal and oral axes for a clear view, thus making intubation easier and faster.

AIM AND OBJECTIVES

Primary objective of the study was to determine the duration of laryngoscopy and intubation and Cormack - Lehane grading when intubating with McGrath MAC, Truview video laryngoscope and Macintosh laryngoscope. Secondary objectives of the study were to determine the number of attempts and optimization manouveres required to intubate.

MATERIALS AND METHODS

This study was conducted on total of 120 patients in age 20-70 years, either sex, with American Society of Anaesthesiologists physical status classes I or II scheduled for elective surgery under general anaesthesia. They were randomly assigned equally to group 1, 2 and 3 ( = 40) to be intubated by Mcgrath MAC video laryngoscope, Truview video laryngoscope and Macintosh laryngoscope respectively. Parameters recorded were duration of laryngoscopy and intubation, Cormack Lahane grading, ease of intubation, number of attempts and optimisation manouveres required for intubation.

STATISTICAL ANALYSIS

Comparison of mean value among the three groups was done using student t test and percentage comparison was done using chi square test. To compare more than two variables ANOVA test was used. The values of less than 0.05 was considered statistically significant.

RESULTS

Duration of laryngoscopy was significantly less in McGrath MAC group when compared to Truview group ( = 0.02) and to Macintosh group ( < 0.001) and the duration of intubation was comparable among all three study groups ( > 0.05). The difference in Cormack - Lehane grading was not significant between McGgrath MAC and Trueview ( = 0.71) but was significant between McGrath MAC and Macintosh ( = 0.002) and Trueview and Macintosh ( = 0.002). Ease of intubation was better in McGrath MAC and Truview groups compared to Macintosh group ( < 0.05). Intubation was successful in the first attempt in 39 (97.50%) patients in McGrath MAC group, 40 (100%) patients in Truview group and 35 (87.50%) patients in Macintosh group. McGrath MAC and Truview groups performed better with respect to optimization manoeuvres compared to Macintosh group ( < 0.05). Trauma was observed in 2 (5%) patients in Truview group and 5 (12.50%) patients in Macintosh group. In McGrath MAC group, no patient underwent any trauma.

CONCLUSION

Although duration of laryngoscopy was significantly shorter in McGrath as compared to Truview video laryngoscope and Macintosh laryngoscope but the duration of intubation was comparable between the three groups. Both these video laryngoscopes performed significantly better than Macintosh laryngoscope with respect to laryngoscopic view, requirement of optimization manoeuvre and need for second attempt for intubation.