Is older still good, or even better? Evaluation of possibility of using Miller laryngoscope for intubation in adults and comparison with the most widely used Macintosh laryngoscope. Protocol of a crossover randomized control trial.

Background: Macintosh laryngoscope is the most widely used laryngoscope for intubation. In some patients, e.g. with flaccid, drooping, aplastic epiglottis, usage of this laryngoscope, or even videolaryngoscopes, may not provide visualization of a glottis. Elevation of the laryngopharynx, like in intubation with Miller laryngoscope, may significantly improve intubating conditions. Methods: An anaesthesiologist with over 20 years of experience will perform direct laryngoscopy with randomly chosen Miller or Macintosh blade, evaluating the visibility of rima glottidis with Cormack-Lehane classification and POGO score with and without external laryngeal pressure. Then the second evaluation of glottis with other blade type will be obtained and the patient will be intubated. Comparison of the rima glottidis visibility when using both blades will be the primary endpoint of the study. The secondary endpoints consist of: demonstrating whether there is a group of adult patients in whom the use of the Miller blade associated with better vocal cord visibility may be predicted based on an anesthesiological examination, and whether external laryngeal pressure improves vocal cord visualization more when using the Miller blade compared with the Macintosh blade. Sample size: We performed minimal sample size calculations based on the data derived from the first 60 patients. We assessed the minimal sample size to obtain the alpha of 5 % and power of 90 %. We decide to enroll at least 286 patients. Discussion: this will be the first trial assessing Miller and Macintosh blades in the same population of adult patients. It will determine group of patients in whom Miller laryngoscope will provide better visualization of rima glottidis than Macintosh blade and associated technique, diminishing rate of prolonging intubations and reducing possible aftermaths of hypoxia.

Supraglottic Airway Devices with Vision Guided Systems: Third Generation of Supraglottic Airway Devices.

Supraglottic airway devices are currently widely used for airway management both for anaesthesia and emergency medicine. First-generation SADs only had a ventilation channel and did not provide protection from possible aspiration of gastric content if regurgitation occurred. Second-generation SADs are equipped with a gastric channel to allow the insertion of a gastric catheter and suctioning of gastric content. Additionally, the seal was improved by a change in the shape of the cuff. Some second-generation SADs were also designed to allow for intubation through the lumen using fiberscopes. Although the safety and efficacy of use of SADs are very high, there are still some issues in terms of providing an adequate seal and protection from possible complications related to misplacement of SAD. New SADs which allow users to choose the insertion scope and control the position of SAD can overcome those problems. Additionally, the Video Laryngeal Mask Airway may serve as an endotracheal intubation device, offering a good alternative to fibre-optic intubation through second-generation SADs. In this narrative review, we provide knowledge of the use of video laryngeal mask airways and the possible advantages of introducing them into daily clinical practice.

Comparison of the macintosh and airtraq laryngoscopes in morbidly obese patients: a randomized and prospective study.

STUDY OBJECTIVE: Morbid obesity is associated with a difficult management of the airway. There is no agreement on these patients being difficult to intubate, but if they are difficult to ventilate with facial mask, then the fast control of their airway becomes a priority. This study compares the quickness and success in tracheal intubation, glottic view, hemodynamic response, and complications from the use of the Macintosh and Airtraq laryngoscopes in morbidly obese patients for scheduled surgery. DESIGN: Prospective, observational, and randomized study. SETTING: Operating room. PATIENTS: Forty-six American Society of Anesthesiologists III patients. INTERVENTIONS: Patients were randomly assigned to undergo tracheal intubation using a Macintosh (n=23) or an Airtraq laryngoscope (n=23). MEASUREMENTS: The following were compared: intubation time, laryngeal vision, the necessity of additional maneuvers to carry out the tracheal intubation, the success of the maneuvers, complications, and hemodynamic response. MAIN RESULTS: The preoperative conditions of the studied patients were similar in both groups. The average time of the intubation was 17.27±16.1 seconds and 22.11±13.62 seconds in the Airtraq and Macintosh groups, respectively (P=.279). With the Airtraq device, 95.65% of patients presented a glottic view 1 and 2a (P=.006) and less optimizing maneuvers were needed to perform the tracheal intubation (P=.001). There were no cases of difficult intubation, failed intubation, or difficult ventilation. A statistically significant increase in the heart rate was detected with the use of the Macintosh laryngoscope. A patient with redundant epiglottis could not be intubated with the Airtraq laryngoscope. CONCLUSION: Both devices allow quick and safe management of the airway. The Airtraq laryngoscope improved the glottic view by the modified Cormack-Lehane classification, reduced the need for additional maneuvers for tracheal intubation, and also reduced the degree of sympathetic stimulus detected by a minor increase in heart rate after tracheal intubation.