The Role of Indirect Laryngoscopy, Clinical and Ultrasonographic Assessment in Prediction of Difficult Airway

Abstract

Objectives Pre‐operative airway evaluation is essential to decrease the proportion of possible mortality and morbidity due to difficult airway (DA). The study aimed to evaluate the accuracy of pre‐operative ultrasonographic airway assessment (UAA) and indirect laryngoscopy (IL) in predicting DA. Study Design Prospective obsevational study. Methods Preoperative clinical examination (body mass index [BMI], mallampati classification [MP], thyromental distance, sternomental distance, neck circumference), UAA (epiglottis‐skin distance [ESD], hyoid bone‐skin distance [HSD], the thickness of tongue root [ToTR], anterior commissure‐skin distance [ACSD]) and IL with the rigid 70‐degree laryngoscope were performed to predict DA (Cormack‐Lehane grade 3 and 4). The sensitivity, specificity, positive predictive value (PP), and negative predictive values of the parameters were assessed. Results Twenty‐two of 140 (15.7%) patients were diagnosed with DA. The cut‐off points of ESD, HSD, ToTR, ACSD, and BMI were 2.09 cm, 0.835 cm, 4.05 cm, 0.545 cm, and 27.10, respectively. AUC values were 0.874, 0.885, 0.871, 0.658, and 0.751 in the same order. AUC values for IL and MP were 0.773 and 0.925, respectively. MP and HSD had the best sensitivity (91%), IL grading had the best specificity (100%), and PP (100%) value among all measurements. The best‐balanced sensitivity (91%), specificity (97%), and PP (88%) values were obtained by combining the IL with MP and ESD or with MP and HSD. Conclusions Ultrasonographic measurements and IL were found significantly correlated to predict DA. Combined parameters, the IL with MP and ESD or with MP and HSD, are the best parameters in predicting the DA. Level of Evidence 4 Laryngoscope, 131:E555–E560, 2021

2022 American Society of Anesthesiologists Practice Guidelines for Management of the Difficult Airway *

“…Topics related to interventions intended to prepare for difficult airway management include (1) the availability of equipment for airway management (e.g., items for anesthetizing locations, portable storage unit, cart, or trolley for difficult airway management); (2) informing the patient with a known or suspected difficult airway; (3) preoxygenation; (4) patient positioning; (5) sedative administration; (6) local anesthesia; (7) supplemental oxygen during difficult airway management; (8) patient monitoring; and (9) human factors.## Literature Findings. Although the need for immediate access to difficult airway management equipment is a well accepted practice, the literature is insufficient to directly evaluate outcomes associated with the availability of such equipment.…”

“…Adjuncts that may be employed during intubation attempts include tracheal tube introducers, rigid stylets, intubating stylets, or tube changers and external laryngeal manipulation. 8 Other options include, but are not limited to, proceeding with procedure utilizing face mask or supraglottic airway ventilation. Pursuit of these options usually implies that ventilation will not be problematic.…”

“…Adjuncts that may be employed during intubation attempts include tracheal tube introducers, rigid stylets, intubating stylets, or tube changers and external laryngeal manipulation. 8 Includes postponing the case or postponing the intubation and returning with appropriate resources (e.g., personnel, equipment, patient preparation, awake intubation). 9 Other options include, but are not limited to, proceeding with procedure utilizing face mask or supraglottic airway ventilation.…”

Concordancia de la valoración de vía aérea por ultrasonido versus escalas tradicionales y su relación con complicaciones de la intubación orotraqueal

“…Por lo tanto, es importante en futuros estudios evaluar la utilidad de otros parámetros por US y determinar cuáles parámetros ultrasonográficos son los de mejor desempeño para predecir vía aérea difícil de forma adicional a la detección de anormalidades estructurales o anatómicas de la vía aérea, ya que falta estandarización y recomendaciones basadas en la evidencia para seleccionar los mejores parámetros ultrasonográficos de cabeza y cuello que pronostiquen la vía aérea difícil. [20][21][22][23]…”

Glottic Opening Appearance is Not Sufficient for Every Endotracheal Intubation

“…

We read with interest the article by Altun et al 1 as the difficult airway is a life-threatening emergency, and predicting difficult intubation is an issue that especially anesthesiologists and Ear, Nose, and Throat (ENT) surgeons, have been working on for years.We want to contribute to this issue and criticize the authors' research.An ENT surgeon performed indirect laryngoscopy (IL), and patients classified as Grade 3 to 4 were assumed to have a difficult airway. 2 However, approximately 80% of patients classified as Grade 3 to 4 actually have easy intubation, and 6% of patients classified as Grade 1 to 2 have difficult intubation.

…”