Predictors of Difficult Tracheal Intubation in Adult Surgical Patients: A Prospective Observational Study
Keywords:
Difficult intubation, Surgical, BMI.Abstract
Background: Difficult tracheal intubation is an important airway-related challenge during general anaesthesia and may result in
repeated intubation attempts, airway trauma and perioperative complications. Identification of patients at increased risk during
preoperative assessment allows appropriate preparation and planning. The present study evaluated demographic, clinical and airwayrelated
predictors of difficult tracheal intubation in adult surgical patients.
Methods: This prospective observational study included 300 adult patients aged ≥18 years scheduled for elective surgery under general
anaesthesia with planned tracheal intubation. Preoperative assessment included age, sex, body mass index, comorbidities, modified
Mallampati class, mouth opening, thyromental distance, neck movement and dentition. During laryngoscopy, Cormack–Lehane
grade was recorded. Difficult tracheal intubation was defined as Cormack–Lehane grade III or IV. Associations between potential
predictors and difficult intubation were assessed using appropriate statistical tests, followed by multivariable logistic regression to
identify independent predictors.
Results: Difficult tracheal intubation was observed in 27 (9.0%) patients. Its incidence was significantly higher among patients aged
≥60 years, males, patients with BMI ≥30 kg/m² and those with comorbidities. Significant associations were observed with modified
Mallampati class III–IV (33.9% vs. 3.3%), mouth opening <3 cm (40.9% vs. 3.5%), thyromental distance <6.5 cm (29.9% vs. 3.0%),
restricted neck movement (42.1% vs. 4.2%) and abnormal dentition (62.5% vs. 6.0%) (p<0.05). On multivariable analysis, Mallampati
class III–IV, restricted neck movement, mouth opening <3 cm, thyromental distance <6.5 cm, abnormal dentition, BMI ≥30 kg/m²
and age ≥60 years remained independently associated with difficult intubation.
Conclusion: Difficult tracheal intubation occurred in a clinically relevant proportion of adult surgical patients. A systematic assessment
incorporating demographic and multiple airway parameters may improve preoperative identification of patients at increased risk.
References
Ahmad I, El-Boghdadly K, Bhagrath R, Hodzovic I, McNarry
AF, Mir F, et al. Difficult Airway Society guidelines for
awake tracheal intubation (ATI) in adults. Anaesthesia.
;75(4):509-528.
Apfelbaum JL, Hagberg CA, Connis RT, Abdelmalak BB,
Agarkar M, Dutton RP, et al. 2022 American Society of
Anesthesiologists practice guidelines for management of the
difficult airway. Anesthesiology. 2022;136(1):31-81.
Narkhede HH, Muranjan MN, Nair AS, Ghodki PS. Difficult
laryngoscopy and intubation in the Indian population: an
assessment of anatomical and clinical risk factors. Indian J
Anaesth. 2013;57(6):569-575.
Myatra SN, Shah A, Kundra P, Patwa A, Ramkumar V,
Divatia JV, et al. All India Difficult Airway Association
guidelines for the management of unanticipated
difficult tracheal intubation in adults. Indian J Anaesth.
;60(12):885-898.
Shiga T, Wajima Z, Inoue T, Sakamoto A. Validation of
modified Mallampati test with addition of thyromental distance
and sternomental distance to predict difficult endotracheal
intubation in adults. Indian J Anaesth. 2014;58(3):252-257.
Khan ZH, Mohammadi M, Rasouli MR, Farrokhnia F, Khan
RH. The diagnostic value of the upper lip bite test combined
with the Mallampati score for prediction of difficult tracheal
intubation. J Clin Anesth. 2009;21(7):485-489.
Shah PJ, Dubey KP, Yadav JP. Validity of thyromental height
test as a predictor of difficult laryngoscopy: a prospective
evaluation comparing modified Mallampati score, interincisor
gap, thyromental distance, neck circumference, and neck
extension. J Anaesthesiol Clin Pharmacol. 2018;34(2):238-
Ramachandran S, Kumar A, et al. Evaluation of neckcircumference-
thyromental-distance ratio as a predictor of
difficult intubation: a prospective, observational study. Indian
J Anaesth. 2023;67(5):463-469.
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