Correlation Between Anthropometric Characteristics and Age-based Formulas for Uncuffed Pediatric Endotracheal Tube

Estimation of Correlation Betweeen Antropometric Characteristics of Children up to 8 Years and Age-based Formulas for Uncuffed Endotracheal Tube in Elective Intubated Children During General Anesthesia

The goal of this observational study is to investigate the correlation between anthropometric characteristics, such as finger circumferences, body weight, body height, and body mass index, and age-based formulas for uncuffed tube size in pediatric patients up to 8 years of age.

Patients who met inclusion criteria entered the study. All included patients were premedicated with midazolam 0.1mg/kg IV 30 minutes before general anesthesia. Induction: propofol 2,5mg/kg IV, rocuronium 0,6mg/kg IV, fentanyl 3mcg/kg IV; maintenance: sevoflurane 1vol% - 2vol%, fentanyl 3mcg/kg IV as needed. reversion of neuromuscular block was achieved using sugammadex. Trachea was intubated using direct laryngoscopy. Intubation performed one anesthesiologist with more than 10 years of clinical experience in pediatric anesthesia. Initial choice of endotracheal tube (ET) was based on the size of little finger. Proper position of ET was confirmed with chest auscultation, capnography and capnometry. If placing ET was difficult or air leak was not detected using inspiratory pressure > 25cmH2O,ET was replaced with 0,5mm smaller one. If there was air leak using inspiratory pressure < 10 mmHg ET was replaced with 0.5mm bigger one. All children were ventilated using protective strategy. After intubation, measures were made:

1. Finger's circumference was measured with flexible ruler tape (in millimeters). The tape was wrapped around the base of the finger. Circumferences of index finger, middle finger, ring finger and small finger were documented for each hand.
2. Data of body weight, body height and body mass index were taken from patients history.
3. Sizes of used endotracheal tubes were documented.
4. Calculations of ET tube size using age based formulas were made:

for children over 2 years ID (mm) = god/4+4 for children under 2 years of age ODcal (mm) = 0,00223x age(days)+4.88

Inclusion Criteria:

• Age up to 8 years of age;
• Children without congenital and acquired anomalies of the trachea;
• Children in whom tracheal intubation is planned as part of the anesthesia plan

Exclusion Criteria:

• Age over 8 years of age;
• The presence of congenital and acquired anomalies of the trachea;
• Children who are already intubated; and failure to obtain informed consent