Ultrasonographic Parameters in Prediction of Difficult Laryngoscopy in Non-suspected Difficult Airway Patients

Use of Ultrasonographic Parameters in Preoperative Prediction of Difficult Laryngoscopy in Non-suspected Difficult Airway Patients Undergoing Elective Surgery; a Prospective Observational Study

This study aims to evaluate the ultrasonographic parameters (distance from skin to epiglottis (DSE) and distance from skin to vocal cords (DSVC)) as preoperative predictors of difficult laryngoscopy in non-suspected difficult airway patients undergoing elective surgery.

Study Overview

• Status: Completed
• Conditions: Ultrasound; Prediction; Difficult Laryngoscopy
• Intervention / Treatment: Procedure: Ultrasound

Detailed Description

Airway management is an integral part of general anesthesia. It simply aims to secure the patient's airway and achieve adequate ventilation and oxygenation for the patient undergoing surgery under general anesthesia. Unsuccessful airway management due to the unexpected difficulty in laryngoscopy is a life-threatening situation and may lead to morbidity and mortality.

Many conventional clinical tests are used in preoperative airway assessment such as modified Mallampati classification, Thyro-mental distance, inter-incisor distance, cervical mobility, and neck circumference, which are used to predict difficulty in the airway, but they have limited value and low sensitivity and specificity. Difficult laryngoscopy cannot be always predicted based on the preoperative assessment by conventional clinical tests. Some patients are thought to have an easy airway by clinical tests, but they show an unexpected difficulty in the laryngoscopy.

The laryngeal view of the patient can be assessed and graded during direct laryngoscopy using the Cormack and Lehane grading scale and its modification that describes the laryngoscopy as easy or difficult.

Ultrasonography is a valuable promising tool for preoperative airway evaluation through identifying important sonoanatomy of the upper airway such as epiglottis, thyroid cartilage, and vocal cords.

• Study Type: Observational
• Enrollment (Actual): 85

Contacts and Locations

Study Locations

• Egypt
  • El-Gharbia
    • Tanta, El-Gharbia, Egypt, 31527
      • Tanta University

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Adult; Older Adult
• Accepts Healthy Volunteers: No

• Sampling Method: Non-Probability Sample

Study Population

This retrospective observational study will be carried out on 85 patients at Tanta University Hospital in the anesthesia department over a period of one year from May 2022 to May 2023, which may be extended after approval from the institutional ethical committee of the faculty of medicine at Tanta University.

Laryngeal view grading according to the modified Cormack and Lehane grading scale where grades 1 and 2a are considered easy laryngoscopy and grades 2b, 3, and 4 are considered difficult laryngoscopy.

Description

Inclusion Criteria:

• Aged 18 - 65 years.
• Both sexes.
• Patients who aren't suspected to have a difficult airway after preoperative airway assessment by conventional clinical tests such as modified Mallampati classification (MMC), thyromental distance (TMD), inter-incisor distance (IID), cervical mobility (CM), And neck circumference (NC).
• American society of anesthesia (ASA) I, II, and III physical status.
• Scheduled for elective surgery under general anaethesia.

Exclusion Criteria:

• Patients with maxillofacial injury and airway trauma.
• Patients with a history of previous difficult intubation.
• Patients with anatomical abnormalities.
• Neck scarring, swelling, or burn.
• Pregnancy.
• Obesity.

Study Plan

How is the study designed?

Number of groups / cohorts

2

Cohorts and Interventions

Group / Cohort	Intervention / Treatment
Easy laryngoscopy; Laryngeal view grading according to the modified Cormack and Lehane grading scale where grades 1 and 2a are considered easy laryngoscopy and grades 2b, 3, and 4 are considered difficult laryngoscopy.	Procedure: Ultrasound; Ultrasonographic parameters: in the parasagittal plane (1cm from midline) with the patient lying supine, without a pillow, head, and neck in the neutral position, looking straight ahead with mouth closed and the tongue on the floor of the mouth without any movement.
Difficult laryngoscopy; Laryngeal view grading according to the modified Cormack and Lehane grading scale where grades 1 and 2a are considered easy laryngoscopy and grades 2b, 3, and 4 are considered difficult laryngoscopy.	Procedure: Ultrasound; Ultrasonographic parameters: in the parasagittal plane (1cm from midline) with the patient lying supine, without a pillow, head, and neck in the neutral position, looking straight ahead with mouth closed and the tongue on the floor of the mouth without any movement.

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Correlation between the ultrasonographic parameters and the modified Cormack and Lehane grading scale	Correlation between the ultrasonographic parameters (distance from skin to epiglottis ( DSE) and distance from skin to vocal cords (DSVC)) and the modified Cormack and Lehane grading scale of laryngoscopy as easy or difficult	10 minutes during intubation.

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Sensitivity of ultrasonographic distance from skin to epiglottis to predict difficult laryngoscopy.	Measurement of Sensitivity of ultrasonographic distance from skin to epiglottis to predict difficult laryngoscopy. Laryngeal view grading according to the modified Cormack and Lehane grading scale where grades 1 and 2a are considered easy laryngoscopy and grades 2b, 3, and 4 are considered difficult laryngoscopy.	10 minutes during intubation.
Sensitivity of ultrasonographic distance from skin to vocal cords to easy laryngoscopy.	Measurement of Sensitivity of ultrasonographic distance from skin to epiglottis to predict easy laryngoscopy. Laryngeal view grading according to the modified Cormack and Lehane grading scale where grades 1 and 2a are considered easy laryngoscopy and grades 2b, 3, and 4 are considered difficult laryngoscopy.	10 minutes during intubation.
Specificity of ultrasonographic distance from skin to epiglottis to predict difficult laryngoscopy.	Measurement of Specificity of ultrasonographic distance from skin to epiglottis to predict difficult laryngoscopy. Laryngeal view grading according to the modified Cormack and Lehane grading scale where grades 1 and 2a are considered easy laryngoscopy and grades 2b, 3, and 4 are considered difficult laryngoscopy.	10 minutes during intubation.
Specificity of ultrasonographic distance from skin to vocal cords to easy laryngoscopy.	Measurement of Specificity of ultrasonographic distance from skin to epiglottis to predict easy laryngoscopy. Laryngeal view grading according to the modified Cormack and Lehane grading scale where grades 1 and 2a are considered easy laryngoscopy and grades 2b, 3, and 4 are considered difficult laryngoscopy.	10 minutes during intubation.

Collaborators and Investigators

• Sponsor: Tanta University

Study record dates

Study Major Dates

• Study Start (Actual): May 1, 2022
• Primary Completion (Actual): May 1, 2023
• Study Completion (Actual): May 1, 2023

Study Registration Dates

• First Submitted: September 18, 2023
• First Submitted That Met QC Criteria: September 18, 2023
• First Posted (Actual): September 25, 2023

Study Record Updates

• Last Update Posted (Actual): September 25, 2023
• Last Update Submitted That Met QC Criteria: September 18, 2023
• Last Verified: September 1, 2023

More Information

Terms related to this study

• Other Study ID Numbers: 35566/6/22

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: YES
• IPD Plan Description: The data will be available upon a reasonable request from the corresponding author after the end of the study for one year.
• IPD Sharing Time Frame: After the end of the study for one year.
• IPD Sharing Access Criteria: The data will be available upon a reasonable request from the corresponding author.
• IPD Sharing Supporting Information Type: STUDY_PROTOCOL

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No