A Prospective Observational Study to Determine the Usefulness of Ultrasound Guided Airway Assessment Preoperatively in Predicting Difficult Airway

Mirunalini, G (2015) A Prospective Observational Study to Determine the Usefulness of Ultrasound Guided Airway Assessment Preoperatively in Predicting Difficult Airway. Masters thesis, Stanley Medical College, Chennai.

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Abstract

AIM OF THE STUDY: The primary aim of this study was to assess the usefulness of ultrasonogram as a preoperative assessment tool in identifying difficult airway. To compare and correlate the ultrasound view of the airway and clinical airway assessment with Cormack Lehane classification of the direct laryngoscopy. METHODS: 150 patients who were to undergo elective surgery and required endotracheal intubation were included in the study. Patients with no teeth and head and neck anatomical abnormality were excluded from study. On the previous day evening of surgery, Patients were shifted to the ultrasound room in the department of anaesthesiology and clinical airway assessment which included Mallampatti's classification, inter incisor gap and thyromental distance were measured. The ultrasound airway assessment was done to measure the thickness of soft tissues in the anterior neck at 3 levels namely (a) hyoid bone, (b) thyrohyoid membrane and (c) suprasternal notch. The patient's demographic details like age, sex, height and weight were also recorded. On the day of surgery, the attending anesthesiologist provided anesthesia to the patient according to the standardization measures explained to them by the anesthetists who performed the airway assessment. The Cormack-Lehane was recorded. Statistical analysis was done using the collected data. RESULTS: The statistic analysis tools that were used in this study for comparison between demographic variables, ultrasound measurements and Cormack-Lehane classification was independent t test an Chi square test. To evaluate for correlation between clinical assessment and ultrasound assessment, Spearman's Rank correlation coefficient was used. There was no statistical significance between the demographic variables like age (P=0.613), sex (P=0.670) and height (P=0.614) of the patients and the occurrence of difficult airway. Among the demographic variables, significant correlation was found between the weight (P=0.000) and difficult airway. The ultrasound measurements made at the 3 levels (a) hyoid bone, (b) thyrohyoid membrane and (c) suprasternal notch level showed significant results. The P values for each of the levels are P=0.000, P=0.000 and P=0.000 respectively. Among the 3 levels, the measurement made at thyrohyoid membrane level (skin to epiglottis thickness) was found to be highly sensitive(100%) and specific(99.3%). A cutoff point of 2.33cms was calculated using the Receiver Operating Characteristic curve (ROC curve). This cutoff point delineates difficult airway and difficult airway. No significant correlation was found between clinical assessment and ultrasound assessment. CONCLUSION : Based on this study we concluded that ultrasound can be used as a reliable tool to identify difficult airway by measuring the thickness of soft tissues in the anterior part of neck. The measurement made at thyrohyoid membrane level is more accurate than the other 2 levels.

Item Type: Thesis (Masters)
Uncontrolled Keywords: Ultrasound ; Difficult airway prediction ; Airway assessment ; Cormack-Lehane classification ; Soft tissue thickness in neck.
Subjects: MEDICAL > Anaesthesiology
Depositing User: Punitha K
Date Deposited: 07 May 2018 03:43
Last Modified: 08 May 2018 01:50
URI: http://repository-tnmgrmu.ac.in/id/eprint/7569

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