Determination of the appropriate sizes of oropharyngeal airways in adults: correlation with external facial measurements A randomised crossover study

Introducing the First Distal Pharyngeal Airway

Airway obstruction during anesthesia is a common occurrence with potentially serious outcomes. Increasingly, patients are older, heavier, and more likely to have obstructive sleep apnea-all heightened risk factors for airway complications. These patients undergo procedures where distal pharyngeal tissues can relax, obstructing the airway. As a result, there is a need for airway devices that can stent open distal pharyngeal tissues to maintain adequate ventilation. To physically address this problem, the new distal pharyngeal airway (DPA) prevents airway obstruction and enables providers to maintain ventilation.

Guedel oropharyngeal airway: The validation of facial landmark-distances to estimate sizing in children - Visualisation by magnetic resonance imaging (GUEDEL-I): A prospective observational study

OBJECTIVE

To validate the ERC-recommended facial landmark-distance for oropharyngeal airway sizing in children.

METHODS

We conducted a prospective observational study in anaesthetised, spontaneously breathing children ≤12 years undergoing cranial MRI. Oropharyngeal airways were inserted following the distance from the maxillary incisors to the mandibular angle. Primary outcome was the rate of properly sized oropharyngeal airways on MRI, defined as the distal end positioned within 10 mm from the epiglottis without contacting it. Secondary outcomes were the occurrence of tongue protrusion, oropharyngeal airways clinical efficacy, and related adverse events. Furthermore, we calculated probabilities for the estimation of proper size when considering five facial landmark-distances and optimal rules based on biometric parameters.

RESULTS

In 94 children with a mean (SD) age of 4.7 (±3) years, 47.9% [95%-CI 38%-57.9%] oropharyngeal airways were properly sized, while 23.4% [95%-CI 15.9%-33%] were undersized, and 28.7% [95%-CI 20.5%-38.7%] oversized. Tongue protrusion occurred in 59.1% [95%-CI 38.2%-77.2%] of undersized and 15.6% [95%-CI 7.6%-29.2%] of properly sized oropharyngeal airways. No oropharyngeal airway required replacement. Comparing probabilities for five landmark-distances, "maxillary incisors to the angle of the mandible" proved superior for proper sizing at 41.2% [95%-CI 32%-51.7%]. The best-fit formula was "22.43 + 17.54 × log(weight[kg])" with a probability of 61.7% [95%-CI 51.5%-70.9%].

CONCLUSION

Although the facial landmark-distance "maxillary incisors to the angle of the mandible" does not reliably predict oropharyngeal airway size, no clinical problems have been encountered. Since it can be considered the least inaccurate facial landmark-distance, it can serve as an approximation, but the efficacy of oropharyngeal airways should be evaluated clinically.

REGISTERED CLINICAL TRIAL

German Clinical Trials Register; DRKS00025918.