ABSTRACT
BACKGROUND: Videolaryngoscopy has proven advantageous over direct laryngoscopy for a variety of outcome variables, most importantly, making laryngoscopy more successful. We tested whether three videolaryngoscopes (VLS), McGrath® series 5 (Aircraft Medical Ltd, Edinburgh, UK), C-MAC® (Karl Storz, Tuttlingen, Germany) and GlideScope® Cobalt (Verathon Medical, Bothell, WA, USA) exert reduced forces on maxillary incisors and lower teeth, and compared them with a classic Macintosh MAC 3 laryngoscope blade during laryngoscopy. METHODS: In this randomized crossover trial, we included 141 patients (ASA I-III) with non-anticipated difficult airways. They were randomly allocated to undergo direct laryngoscopy and videolaryngoscopy performed with one of three VLS. Primary outcome was the magnitude of forces applied to the maxillary incisors during laryngoscopy. Secondary outcomes were the frequency with which forces were applied, and the magnitude of forces applied to the lower teeth. RESULTS: Forces applied to the maxillary incisors during direct classic laryngoscopy were on average higher than forces applied during videolaryngoscopy. Among the VLS the average force applied was significantly lower for the C-MAC® as compared to the McGrath® and the GlideScope® VLS. The frequency with which a force was applied to the maxillary incisors was significantly lower for the C-MAC®, compared to the other VLS and classic Macintosh laryngoscope. The number of cases in which force was applied to the lower teeth was smallest for the McGrath VLS. CONCLUSION: Forces exerted on maxillary incisors are lower using video-assisted Macintosh blade laryngoscopy compared to classic direct laryngoscopy. The number and magnitude of forces applied to maxillary incisors also differ substantially between different VLS.
Subject(s)
Airway Management/methods , Laryngoscopy/methods , Tooth Injuries/etiology , Adult , Aged , Airway Management/adverse effects , Cross-Over Studies , Female , Humans , Laryngoscopes , Laryngoscopy/adverse effects , Male , Middle Aged , Tooth Injuries/epidemiologyABSTRACT
INTRODUCTION: Previous studies comparing Glidescope and classic direct laryngoscopy did not show an attenuation of CV responses to endotracheal intubation. In the present study, we hypothesize that indirect videolaryngoscopy can attenuate cardiovascular responses to endotracheal intubation. METHODS: In a randomized cross-over study, eighty adults (ASA PS II-III) were included. Both direct and indirect videolaryngoscopies were used in a random order, in the same patient. Cardiovascular responses to intubation were recorded as a relative change in rate pressure product (RPP = systolic blood pressure times heart rate) from baseline values. A linear mixed model was used to study the association between the outcome variable RPP and the type of laryngoscope used. RESULTS: The relative increase of the RPP at intubation was significantly smaller (i.e. 27%, P < 0.001) using videolaryngoscopy compared to the classic direct laryngoscopy. Cardiovascular responses were blunted by an additional 10.2% (P = 0.029), when the patient was on beta blockade. CONCLUSIONS: Our study shows less hemodynamic responses during endotracheal intubation using indirect videolaryngoscopy compared to classic direct laryngoscopy.
