Prospective model-based comparison of different laryngoscopes for difficult intubation in infants

Background: Difficult intubation in infants is uncommon but may be a challenge for the anesthesiologist. Many optical-assisted techniques are available to ease endotracheal placement of tube but have not been systemically evaluated for pediatric practice. Aim: The study was performed to compare conventional pediatric Macintosh with different optical laryngoscopes in difficult endotracheal intubation in infants. We hypothesized that inexperienced anesthetists would perform more successful with optical devices and that differences between the devices would be found. Methods/Materials: In this randomized controlled study, 30 anesthesia residents performed endotracheal intubation in an infant model of difficult airway presenting with airway obstruction and neck immobilization. Primary endpoints were intubation success rate and intubation time. Beyond that glottis view, dental trauma and difficulty of technique were evaluated and measured by a study observer. Macintosh, Airtraq (R), Storz DCI (R)-, and Gyrus Infant Bullard (R) laryngoscopes were used in random order. After standardized briefing every resident had three attempts of at most 120 s with every device to place a 3-mm tube into the trachea. Glottis view and difficulty of technique were rated by the residents using classification of Cormack/Lehane and Visual Analogue Scale (VAS; 0 = easy to 10 = very difficult). Results: Success rate was 41% with conventional Macintosh, 43% with Airtraq (R), 62% with Storz DCI (R), and 100% with Bullard (R) laryngoscopes. Median time from passing the lips to first ventilation was 67 s (Storz DCI (R) laryngoscope), 54 s (Macintosh laryngoscope), 45 s (Airtraq (R) laryngoscope), and 21 s (Bullard (R) laryngoscope), respectively. Dental trauma did not occur with Bullard (R) laryngoscope and was frequent with Storz DCI (R) laryngoscope (39%) and Macintosh laryngoscope (42%). Glottis view was best with Bullard (R) laryngoscope (Grade 1 in 100%) and worst with Macintosh laryngoscope (Grade 1 in 2%). Difficulty of technique was rated with a VAS score of 2 (Bullard (R) laryngoscope), 4.5 (Storz DCI (R) laryngoscope) and 6 (Airtraq (R)- and Macintosh laryngoscopes). Conclusions: Inexperienced anesthetists have higher success rates and shorter intubation times with optical-assisted laryngoscopes compared with conventional Macintosh laryngoscope. Gyrus Infant Bullard (R) laryngoscope significantly undertakes best success rate and shortest intubation time with mildest impact to maxillary dents and easiest technique. Our findings support the hypothesis that optical laryngoscopes can be used successfully by inexperienced anesthetists in simulated difficult pediatric airway conditions.