Factors influencing time of intubation with a lightwand device in patients without known airway abnormality

Abstract Study objective To evaluate the correlation between accepted screening tests for difficult tracheal intubation and ease of intubation with a lightwand blind technique. Design Prospective study. Setting Anesthetic rooms of a university hospital. Patients 122 female, ASA physical status I, II, and III patients requiring tracheal intubation for elective surgery. Interventions After receiving a standardized anesthetic induction, patients first underwent direct laryngoscopy to determine Cormack laryngoscopy grade, then tracheal intubation was performed using a transillumination method. Measurements and main results Patient demographics, Mallampati class (MC), mouth opening (MO; cm), and thyromental distance (TMD; cm) were all measured and the values recorded. Body mass index (BMI; kg/m 2 ) was calculated for each patient. Laryngoscopy grades obtained by laryngoscopy were also recorded. Times to intubation were measured by a chronometer and failures were recorded. Patients were then allocated to groups according to the measured parameters: BMI ≥ 30 kg/m 2 , BMI 2 ; TMD ≥ 6 cm, TMD 2 groups, only the MC III and BMI ≥ 30 kg/m 2 groups represented a statistically significant difference of prolongation. Mean time to intubation in the MC III and BMI ≥ 30 kg/m 2 groups were 13.2 ± 5.4 ( p = 0.011) and 14.8 ± 1.7 ( p ≤ 0.001), respectively. Conclusion Mallampati class III airway significantly increases time to intubation when the transillumination technique is used. BMI ≥ 30 kg/m 2 is another factor that interferes with the ease and success of intubation with this technique.