Thyromental Height Test as a New Method for Prediction of Difficult Intubation in Obese Patients

NCT ID: NCT04439487

Last Updated: 2020-06-19

Basic Information

• Recruitment Status: UNKNOWN
• Total Enrollment: 300 participants
• Study Classification: OBSERVATIONAL
• Study Start Date: 2020-06-01
• Study Completion Date: 2021-06-01

Brief Summary

The main objective of this trial is to assess the clinical usefulness of thyromental height test (TMHT) in prediction of difficult intubation in obese patients scheduled for elective surgical procedures. The secondary aim is to evaluate usefulness of other commonly used predictive tests associated with difficult intubation in obese patients.

Detailed Description

Successful and fast intubation are crucial for the safety of general anaesthesia. Failed intubation and acute hypoxia remain among the major contributing factors of anaesthesia related deaths. Difficult intubation prevalence in literature is very inconsistent and varies between 1.5-20% of cases in general population, to even 50% in obese Thai population.

Obesity remains a challenging problem in perioperative care. It is assumed that the airway access may be restricted due to anatomic changes resulting from excess body weight. There are factors like diagnosed obstructive sleep apnoea or large neck circumference that also relate to occurrence of difficult intubation in obese patients.

There is a number of anthropometric scales and tests used for predicting difficult intubation in obese patients. However, none of them appears to be sensitive and specific enough to effectively predict difficult intubation.

Recently, simple and non-invasive test predicting difficult intubation was introduced-thyromental height test (TMHT). It shows promise as a more effective substitution for frequently cited anthropometric measures. It is based on the height between the anterior border of the thyroid cartilage and the anterior border of the mentum, measured while the patient lies in the supine position with closed mouth.

The main objective of this trial is to assess the clinical usefulness of TMHT in prediction of difficult intubation in obese patients scheduled for elective surgical procedures. The secondary aim is to evaluate usefulness of other commonly used predictive tests associated with difficult intubation in obese patients.

Conditions

Intubation, Intratracheal; Obesity; Predictive Value of Tests

Study Design

• Observational Model Type: COHORT
• Study Time Perspective: PROSPECTIVE

Study Groups

Obese patients requiring general anesthesia

Group consists of consecutive, adult, obese patients undergoing elective surgical procedures requiring general anaesthesia, direct laryngoscopy and intubation. All patients undergo general anesthesia according to a standardised protocol. They are preoxygenated with 100% oxygen breathed through a face mask for 3-5 minutes. Induction of general anaesthesia is achieved with propofol 1,5-2 mg·kg-1 (of Ideal Body Weight) and 0,1mg fentanyl or sufentanil 10µg. Muscle relaxation is accomplished with rocuronium 0.6 mg ·kg-1 (of Ideal Body Weight). Depth of muscular blockade is monitored using Train of Four (TOF) method. The first laryngoscopy attempt is performed at TOF 0. The patient is placed in an optimal, sniffing or ramped position as appropriate and a #3 or #4 Macintosh blade is used. Successful intubation is confirmed with bilateral auscultation and capnography.

Anthropometric measurements during routine preoperative visit

Intervention Type: DIAGNOSTIC_TEST

During routine preoperative anaesthetic visit and physical examination the following predictive test measurements are obtained by a research team member not involved in the further assessment of laryngoscopy: score in modified Mallampati test, Thyromental height, Sternomental distance, Thyromental distance, Neck circumference, Mouth opening distance

Assesment of intubation parameters during induction of general anaesthesia

Intervention Type: OTHER

During induction of general anaesthesia and intubation research team member not involved in obtaining anthropometric measurements notes Number of intubation attempts, Intubation time, Subjective intubation difficulty, Use of bougie and Need of technique modification.

Interventions

Anthropometric measurements during routine preoperative visit

During routine preoperative anaesthetic visit and physical examination the following predictive test measurements are obtained by a research team member not involved in the further assessment of laryngoscopy: score in modified Mallampati test, Thyromental height, Sternomental distance, Thyromental distance, Neck circumference, Mouth opening distance

Intervention Type: DIAGNOSTIC_TEST

Assesment of intubation parameters during induction of general anaesthesia

During induction of general anaesthesia and intubation research team member not involved in obtaining anthropometric measurements notes Number of intubation attempts, Intubation time, Subjective intubation difficulty, Use of bougie and Need of technique modification.

Intervention Type: OTHER

Eligibility Criteria

Inclusion Criteria

• qualification for elective surgical procedures, requiring general anaesthesia, direct laryngoscopy and intubation
• consent for participation in the trail
• age ≥18 years
• BMI ≥30 kg/m2

Exclusion Criteria

• BMI ≤30 kg/m2
• patients overweight due to ascites or tumor
• emergency procedures
• visible anatomic abnormalities
• patients scheduled for awake fibreoptic intubation
• intubation failure
• lack of consent for participation in the trail

• Minimum Eligible Age: 18 Years
• Eligible Sex: ALL
• Accepts Healthy Volunteers: No

Sponsors

Medical University of Silesia

OTHER

Sponsor Role: lead

Responsible Party

Piotr Palaczyński

Principal Investigator

Responsibility Role: PRINCIPAL_INVESTIGATOR

Locations

Medical University of Gdansk

Gdansk, Pomeranian Voivodeship, Poland

Samodzielny Publiczny Szpital Kliniczny nr 1

Zabrze, Silesian Voivodeship, Poland

Countries

Poland

Other Identifiers

TMHT-02

Identifier Type: -

Identifier Source: org_study_id