Ultrasonography for Prediction of Difficult Intubation and Prediction of Endotracheal Tube Size

Study Overview
=================
Brief Summary
-----------------
Aim of our study is to evaluate the predictive value of ultrasonographic (USG) measurement of thyrohyoid distance for difficult intubation and determination of optimal endotracheal tube size by using USG in pediatric patients undergoing elective surgery.

Detailed Description
-----------------
After ethics committee approval and parental consent were obtained, 119 patients undergoing genitourinary surgery or inguinal hernia repair under general anesthesia, were included in study. Patients with head or neck anomalies, syndromic patients, patients undergoing emergency surgery and patients with a history of difficult airway were excluded from the study. Patients were grouped according to their ages; Group I (1-2 years,n=38), Group II (3-5 years,n=46) and Group III (6-8 years,n=35). USG measurements were performed following sevoflurane induction in groups I and II. In group III, USG measurements were performed following premedication with intravenous midazolam 0.05 mg/kg . Thyrohyoid distance, glottic and subglottic diameters were measured with ultrasonography. The size of the endotracheal tube according to Bae's formula ( internal diameter of Endotracheal tube = 0.705 x subglottic diameter - 0.091) was calculated and recorded. Before intubation, endotracheal tube (cuffed/uncuffed) was selected using age-related formulas. In group II, anaesthesia induction was achieved with propofol 2 mg/kg. In all groups, endotracheal intubation was achieved with fentanyl 2μg/kg and rocuronium 0.6 mg/kg. Endotracheal tube size was considered as optimal when a leak was detected at 20-30cmH₂O inflation pressures. If a resistance was felt in the subglottic region, the tube was exchanged with a smaller and was exchanged with a larger (0.5 mm) size if a leak occurred at inflation pressures lower than 20cmH₂O. Intubation duration , Cormack-Lehane scores and Intubation Difficulty Scale scores were recorded. For comparison of age related formula and Bae 's formula, only patients who were intubated with un-cuffed endotracheal tube were evaluated.

Official Title
-----------------
Ultrasonographic Thyrohyoid Distance Measurement for Prediction of Difficult Intubation and Ultrasonographic Prediction of Pediatric Endotracheal Tube Size

Conditions
-----------------
Intubation; Difficult or Failed

Intervention / Treatment
-----------------
* Device: Ultrasonography
* Drug: Sevoflurane
* Drug: intravenous midazolam
* Drug: Propofol
* Drug: fentanyl and rocuronium


Participation Criteria
=================
Eligibility Criteria
-----------------
Inclusion Criteria: Aged between 1 and 8 years Elective surgery Exclusion Criteria: Patients with head or neck abnormalities Syndromic patients Emergency surgery and patients with a History of difficult airway Allergy to ultrasound gel

Ages Eligible for Study
-----------------
Minimum Age: 1 Year
Maximum Age: 8 Years

Sexes Eligible for Study
-----------------
All

Accepts Healthy Volunteers
-----------------
No

Study Plan
=================
How is the study designed?
-----------------

Design Details

Primary Purpose: Prevention
Allocation: Non-Randomized
Intervention Model: Parallel Assignment
Masking: None (Open Label)


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Other: Group I<br>Patients between 1 and 2 years | Device: Ultrasonography<br> <br> Drug: Sevoflurane<br> <br> Drug: intravenous midazolam<br> <br> Drug: fentanyl and rocuronium<br> <br> |
| Other: Group II<br>patients between 3 and 5 years | Device: Ultrasonography<br> <br> Drug: Sevoflurane<br> <br> Drug: Propofol<br> <br> Drug: fentanyl and rocuronium<br> <br> |
| Other: Group III<br>patients between 6 and 8 years | Device: Ultrasonography<br> <br> Drug: Sevoflurane<br> <br> Drug: intravenous midazolam<br> <br> Drug: fentanyl and rocuronium<br> <br> |

What is the study measuring?
-----------------
Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Evidence of difficult intubation (determined with Intubation Difficulty Scale) in patients who have short thyrohyoid distance |  | three years | 
| Consistency of endotracheal tube sizes selected with aged related formulas and with ultrasonographic measurement of subglotic diameter |  | three years |