Can the Ratio of Chin-neck Circumference and Neck Circumference to Chin-neck Circumference Predict Difficult Intubation in Obese Patients?

Completed

• Conditions: Difficult Airway Intubation; Obesity Adult Onset
• Interventions: Other: intubation; Other: mask ventilation

• Registration Number: NCT04712227
• Lead Sponsor: Kecioren Education and Training Hospital

Brief Summary

Importance and Purpose of the Study: Proper management of the difficult airway is an important part of preventing anesthesia-related mortality and morbidity. Difficult airways, characterized by both difficult mask ventilation and difficult intubation, are common in obese patients. Many studies have shown an association between obesity or morbid obesity and difficult intubation. We thought that in obese patients, increased subcutaneous fat tissue in the nape of the neck may restrict the head extension and cause difficult intubation and difficult mask ventilation, and the increase in the chin-nape circumference may predict difficult intubation and difficult mask ventilation. We also predicted that the ratio of neck circumference to chin-nape circumference might predict difficult intubation and difficult mask ventilation.

Materials and Methods: After the approval of the ethics committee, obese patients who require tracheal intubation, undergo elective surgery, over the age of 18, with a body mass index (BMI) of more than 30 were evaluated. Patients with cervical spine anomaly, emergency procedures, known history of difficult intubation or upper respiratory tract disease, and planned awake intubation were excluded from the study. Mallampati score, mouth opening, upper lip bite test, distance between incisors, thyromental distance, sternomental distance and thyromental height were recorded. Using a tape measure, the neck circumference from the thyroid cartilage level and the chin-neck circumference from the mentum level were measured with the patient in a neutral position. The ratio of neck circumference to thyromental distance and the ratio of neck circumference to chin-nape circumference were calculated from these measurements. Mask ventilation was graded according to the method described by Han et al. After adequate muscle relaxation was achieved, tracheal intubation was performed with an appropriately sized Macintosh blade using direct laryngoscopy. Difficult intubation evaluation was performed using the Difficult Intubation Scale (IDS) based on seven variables.

Results: A statistically significant relationship was found between difficult intubation and the distance between incisors, neck circumference, neck circumference / thyromental distance, neck circumference / sternomental distance, and chin-nape circumference. In the multivariate regression analysis performed with these parameters, the distance between the incisors was \<4.85 cm and the neck circumference\> 41.5 cm was found to be independent risk factors for difficult intubation. A statistically significant relationship was found between difficult mask ventilation and age, male gender, OSAS, neck circumference, neck circumference / thyromental distance, neck circumference / sternomental distance, neck circumference / chin-nape circumference and chin-nape circumference. In the multivariate regression analysis performed with these parameters, it was determined that male gender and neck circumference thicker than 45.5 cm were independent risk factors for difficult mask ventilation.

Conclusion: The ratio of neck circumference to chin-nape circumference and chin-nape circumference are successful in predicting difficult mask ventilation in obese patients. While chin-nape circumference is successful in predicting difficult intubation in obese patients, neck circumference / chin-nape circumference is unsuccessful.

Detailed Description

Not available

Study Timeline

• Study Start: 2019-09-12
• Primary Completion: 2020-02-15
• Study Completion: 2020-06-07
• Status Verified: 2021-01
• Study First Submitted: 2021-01-10
• Study First Submitted QC: 2021-01-13
• Last Update Submitted: 2021-01-13
• Study First Posted: 2021-01-15
• Last Update Posted: 2021-01-15

Recruitment & Eligibility

• Status: COMPLETED
• Sex: All
• Target Recruitment: 4

Inclusion Criteria

Patients who will be operated under general anesthesia with endotracheal intubation, aged 18 years and over, with body mass index (BMI≥30) and ASA 1-3

Exclusion Criteria

Patients with cervical spine anomalies, emergency procedures, known difficult intubation history and awake intubation plan, and those with beard were excluded from the study.

Study & Design

• Study Type: OBSERVATIONAL
• Study Design: Not specified

Arm && Interventions

Group	Intervention	Description
easy intubation	intubation	patients with difficult intubation score less than 5
difficult mask ventilation	mask ventilation	group 3 and 4 by han mask ventilation grouping
difficult intubation	intubation	patients with a difficult intubation score of 5 or more
easy mask ventilation	mask ventilation	group 1 and 2 according to han mask ventilation grouping

Primary Outcome Measures

Name	Time	Method
Parameters associated with difficult intubation in obese patients	always	mallampati score, cormack-lehane score, distance between incisors, neck circumference, ratio of neck circumference to thyromental distance, ratio of neck circumference to sternomental distance and chin-nape circumference

Secondary Outcome Measures

Name	Time	Method
parameters associated with difficult mask ventilation in obese patients	always	age, gender, OSAS, neck circumference, chin-nape circumference, ratio of neck circumference to chin-nape circumference, ratio of neck circumference to thyromental distance, and ratio of neck circumference to sternomenal distance

Trial Locations

Locations (1)

Keçiören training and research hospital; 🇹🇷 Ankara, Turkey