Original Research Article
Year: 2021 | Month: January | Volume: 8 | Issue: 1 | Pages: 716-722
Ultrasound Assessment of Anterior Neck Soft Tissue Thickness as a Predictor of Difficult Laryngoscopy and Intubation in Obese Patients
Deepika Kesarwani1, Neha Chandrakar2, Ruqaiya Bano3, Vijay Vohra4
1Senior Resident Department of Anesthesia and Critical Care, VMMC & Safdarjung Hospital, New Delhi.
2Consultant Ramakrishna Hospital,
3Senior Resident Anesthesia & Critical Care, VMMC & Safdarjung Hospital, New Delhi.
4Chairman of Liver Transplant Medanta-The Medicity Hospital
Corresponding Author: Deepika Kesarwani
ABSTRACT
Background and objective: Maintaining a patent airway is essential for adequate oxygenation and ventilation and it can be life threatening on its failure. Unanticipated difficult intubation being a dreaded concern for the anaesthesiologist. Although obesity increases the risk of difficult intubation but BMI alone is not a good predictor of difficult laryngoscopy. Ultrasound has long been used as a noninvasive and safe tool for diagnosis and assessment of airway. Aim of the study was to determine if ultrasound assessment of anterior neck soft tissue thickness at the level of vocal cord can be used to assess the difficult airway.
Method: 70 morbidly obese patients (BMI>35 kg/m2) were allocated in 2 groups, Group 1 (easy laryngoscopy) and group 2 (difficult laryngoscopy) for prospective observational study scheduled for elective surgery under general anaesthesia with tracheal intubation. Preoperative work up with airway assessment as mouth opening, thyromental distance, neck circumference, Mallampati grading (MO, TMD, NC, MPG) and anterior neck soft tissue thickness by USG at the level of vocal cord were done. Cormack-Lehane grading with laryngoscope were assessed intraoperatively.
Result: Average Soft tissue thickness at the level of vocal cord by USG in group 1(18.3±1.1) and in group 2 (18.6±0.9) and the difference was not statistically significant (p value 0.317) which showed Cormack-Lehane grading is not affected by anterior neck soft tissue thickness. Also no significant difference was found in respect to mouth opening (p value 0.059). Significant difference was found in both the group (easy and difficult laryngoscopy) in respect to TMD (p value 0.032), MPG (p value 0.002) and NC (p value 0.001).
Conclusion: USG assessment of anterior neck soft tissue thickness at the level of vocal cord is not a good predictor of difficult laryngoscopy in obese patients. But this is a small observational study. Other larger randomization studies are required to prove significant results. Among the potential predictors of difficult laryngoscopy MPG, TMD and neck circumference were the only measures that fully distinguished difficult laryngoscopy from easy one.
Keywords: morbid obese, ultrasound, airway assessment.
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