Value of oropharyngeal Mallampati classification in predicting difficult laryngoscopy among obese patients

Abstract

The prediction of difficult intubation in obese patients was investigated by co-estimating the degree of visibility of oropharyngeal structures in conjunction with the respective body mass index. Data were collected prospectively in a series of 1833 consecutive adult patients. Body mass index (BMI) in kg m-2 was used as a measure of obesity (morbid: > 40, moderate: 30-40, no obesity: < 30). The oropharyngeal class findings were assessed using the original methodology as well as by a modification requiring the tongue to be pulled forward by the examiner. Difficult intubation was defined as inadequate exposure of the glottis by direct laryngoscopy. Both oropharyngeal class methodologies were of equal sensitivity, whereas the modified technique presented a significantly higher positive predictive value (50.0% vs. 37.2%, P < 0.01). Statistical analysis revealed an increased risk of difficult laryngoscopy among obese patients compared with subjects with normal body mass index (20.2% vs. 7.6%, P < 0.001). When obesity is estimated with respect to oropharyngeal class the positive predictive value is greatly improved (66.7% vs. 20.2%, P < 0.001). We conclude that obesity which is associated with a disproportionately large base of the tongue, is a predisposing factor for difficult laryngoscopy.

Preoperative predictors of difficult intubation in patients with obstructive sleep apnea syndrome

“…A large prospective study of 1,833 patients identified obesity is a factor predisposing difficult intubation. 12 The mean BMI of our OSAS patients was 27.9 ± 2.9, which would place our patients in their non-obese category.…”

Increased body mass indexper se is not a predictor of difficult laryngoscopy

“…Two patients in CG had their trachea intubated at the third attempt with the gum elastic bougie and external laryngeal pressure applied to facilitate the laryngoscopic view. D Di is sc cu us ss si io on n Obesity has been found to be a risk factor for difficult intubation, 4,12 yet, Meyer 13 and Bond 5 failed to demonstrate a higher occurrence of difficult intubation in morbidly obese patients. Meyer 13 had shown that intubation difficulty in 400 morbidly obese patients was similar to that of non-obese patients.…”

“…4,5 The purpose of our study was to evaluate the impact of specific factors in predicting a DL in morbidly obese patients undergoing elective surgery.…”

Airway Management Using the Intubating Laryngeal Mask Airway for the Morbidly Obese Patient

“…Thus, a body mass index (BMI) Ͼ26 kg/m 2 results in a 3-fold increase in difficult ventilation via a mask (1) and in a 10-fold increased incidence of difficult endotracheal intubation (2,3). Inability to maintain a patent airway can be problematic in the obese, because lung and chest mechanical properties are markedly impaired in sedated, paralyzed obese patients (4).…”

“…Preoperative prediction of potential difficulty with airway management by using individual tests, such as a Mallampati score, seems to have a lesser value in obese patients as compared with lean patients (2). Consequently, anesthesia of morbidly obese patients remains at frequent, but not foreseeable, risk of difficult mask ventilation or tracheal intubation.…”