Flexible Intubation Scope versus Flexible Intubation Scope and Video Laryngoscopy Combination: A Prospective Randomized Clinical Trial

BACKGROUND: In patients with anticipated difficult airways, suboptimal airway management may increase perioperative morbidity and mortality. Combining video laryngoscopy (VL) with a flexible intubation scope (FIS) has been shown to enhance visualization and facilitate endotracheal tube passage in patients with known or anticipated difficult airways. To date, randomized evidence supporting this approach remains limited. METHODS: In this prospective, randomized trial, 135 adults with anticipated difficult airways undergoing elective surgery were randomized 1:1 to intubation with FIS alone or a combined technique using FIS with VL (FIS/VL). The primary end point was the composite rate of difficult endotracheal tube (ETT) placement, defined by one or more of the following: (1) first-attempt intubation time >60 seconds; (2) failure to intubate on the first attempt; or (3) provider assessment of the intubation process as difficult. Provider-rated ease of intubation was recorded immediately following the procedure by the anesthesiologist performing the intubation using a 5-point Likert scale. Scores of 1 (extremely easy), 2 (somewhat easy), and 3 (resistance to tube advancement) were classified as Not Difficult, whereas scores of 4 (difficult) and 5 (unsuccessful) were classified as Difficult/Unsuccessful. For analysis and reporting, the Likert-scale ratings were dichotomized into a binary outcome (Not Difficult vs Difficult/Unsuccessful). The secondary outcome was total intubation time. RESULTS: A total of 144 patients were screened and enrolled, and 135 patients were randomized. Of these, 66 patients were assigned to the FIS/VL arm and 69 patients to the FIS arm. Among the 135 randomized patients, 128 provided analyzable data for the composite primary end point. Overall, the first-pass success rate was 54/58 (93.1%) in the FIS/VL group versus 50/64 (78.1%) in the FIS group; P = .020. Intubation time greater than 60 seconds was similar between groups (33/66 52.4% in the FIS arm vs 24/61 39.3% in the FIS/VL arm; P = .145). Provider-rated ease of intubation considered difficult or unsuccessful occurred in 4/64 (6.1%) of FIS/VL compared to 13/67 (19.4%) of FIS cases ( P = .025). Among the 128 evaluable patients (61 FIS/VL, 67 FIS), the composite primary end point- difficult ETT placement defined as (1) first-attempt intubation time >60 seconds, (2) failure on first attempt at intubation, or (3) provider-rated difficult intubation occurred in 28/61 (45.9%) of FIS/VL versus 40/67 (59.7%) of FIS cases Risk difference (95% CI) = –0.14 (–0.31 to 0.03); P = .118. CONCLUSIONS: In adults with anticipated difficult airways, adding VL to FIS did not significantly reduce the composite rate of difficult ETT placement, although it was associated with fewer repeat attempts and fewer provider-rated difficult/unsuccessful intubations. These findings support the clinical value of dual-visualization strategies to improve first-pass performance metrics, whereas larger trials are needed to determine their effect on composite difficulty end points.