BY TAKING INTUBATION DIFFICULTY SCALE AS GOLD STANDARD IN ASSESSING DIFFICULT INTUBATION AND PREDICTIVE VALUE OF RESTRICTED NECK MOVEMENT

Introduction: The three main causes of respiratory related injuries of anesthesia are inadequate ventilation, esophageal intubation and difficult tracheal intubation. 17% of all respiratory related injuries are due to difficult intubation and it accounts for 28% of anesthesia related deaths’. Airway maintenance during anesthesia is crucial for adequate oxygenation and ventilation and failure to secure airway can lead to tissue hypoxia and ultimately death.

Subjects and Methods: This study involved 126 patients of both genders, aged between I8-70 years undergoing general anesthesia with endotracheal intubation on elective lists Difficult intubation was predicted on restricted neck movement (<80°) and was confirmed on IDS. IDS diagnosis was taken as gold standard and results of restricted neck movement were evaluated accordingly. Written informed consent was taken from every patient.

Results: The age of the patients ranged from 18 years to 70 years with a mean of 42.49 + 14.56 years. There were 64 (50.8%) male and 62 (49.2%) female patients in the study group. There were 52 (41.3%) obese patients. Difficult intubation was confirmed in 90 (71.4%) patients on intubation difficulty scale (as per operational definition)1. The frequency of difficult intubation was higher among obese patients (80.8% vs. 64.9%; p 0.052) however the difference was insignificant. There were 90 (71.4%) true positive patients with 36 false positive patients. It yielded a positive predictive value of 71.4% for restricted neck movement in the prediction of difficult intubation taking IDS as gold standard. Similar positive predictive value was observed across age, gender and obesity groups.

Conclusion: The positive predictive value of restricted neck movement (<80°) was found to be 71.4% in predicting difficult intubation among patients undergoing general anesthesia with endotracheal intubation on elective list while taking intubation difficulty scale as the gold standard.

Keywords: Difficult Intubation. Intubation Difficulty Scale. Restricted Neck Movement.