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Predicted vs. Actual Endotracheal Tube Size in Pediatric Cardiac Surgery for Children with Down Syndrome
Madan M Maddali1, Haitham K Al-Abri2, Is'haq Al Aamri1
1Department of Cardiac Anesthesia, Oman Medical Specialty Board, Department of Cardiac Anesthesia, National Heart Center, Royal Hospital, Muscat, Oman.
Insights
The Cole formula overestimates endotracheal tube (ETT) size in children with Down syndrome undergoing cardiac surgery. Clinical judgment is crucial due to anatomical variations in this population.
Area of Science:
- Pediatric Anesthesiology
- Cardiothoracic Surgery
- Genetics and Rare Diseases
Background:
- Children with Down syndrome face increased risks of upper airway obstruction and smaller tracheal lumens.
- Conditions like subglottic stenosis and laryngomalacia are common in this population.
- The standard Cole formula for endotracheal tube (ETT) sizing may be inaccurate for children with Down syndrome undergoing cardiac surgery.
Purpose of the Study:
- To evaluate the accuracy of the Cole formula in predicting ETT size for pediatric cardiac surgery patients with Down syndrome.
- To compare predicted versus actual ETT sizes across different age groups (<1 year vs. ≥1 year).
- To assess the influence of airway characteristics and co-morbidities on ETT selection.
Main Methods:
- Retrospective cohort study conducted at a single tertiary pediatric cardiac center.
- Inclusion of 182 pediatric patients with Down syndrome undergoing cardiac surgery requiring tracheal intubation with uncuffed ETTs.
- Data analysis included age-stratified comparisons of predicted and actual ETT sizes.
Main Results:
- The Cole formula significantly overestimated the required ETT size in the overall cohort (P < 0.001).
- This overestimation persisted across both age groups (<1 year and ≥1 year), with actual ETT sizes being smaller than predicted (correlation coefficient = 0.797).
- Infants under one year had higher rates of anti-failure medications and complex cardiac anomalies, but these did not influence ETT size selection.
Conclusions:
- The Cole formula is unreliable for predicting ETT size in pediatric cardiac surgery patients with Down syndrome.
- Individual anatomical assessment and clinical judgment are essential for appropriate ETT selection in this population.
- There is a need for refined methods to accurately predict ETT size in children with Down syndrome.
Background:
Children with Down syndrome have a higher risk of upper airway obstruction and smaller tracheal lumens due to conditions like subglottic stenosis and laryngomalacia. While the Cole formula is widely used to predict endotracheal tube (ETT) size in non-syndromic children, this formula may be inappropriate for children with Down syndrome undergoing cardiac surgery.
Objectives:
The primary objective was to determine whether the actual endotracheal tube size used in children with Down syndrome undergoing cardiac surgery matches the size predicted by the Cole formula. The secondary objectives included age-stratified comparisons (<1 year vs. ≥1 year) of predicted versus actual endotracheal tube size used, along with the impact of airway characteristics, drug usage, and postoperative outcomes on the actual endotracheal tube used.
Settings And Design:
A retrospective cohort study at a single tertiary pediatric cardiac center.
Measurements And Main Results:
A total of 182 pediatric patients with Down syndrome who had cardiac surgery were enrolled. Data were collected from patients with Down syndrome who had cardiac surgery with tracheal intubation using uncuffed ETTs. Patients were divided into two groups: those under one year of age and those one year or older.
Results:
The actual ETT size used was statistically different from the size predicted by the Cole formula across all patients (P < 0.001). The difference between the actual and predicted ETT sizes remained significant in both age groups and did not decrease with age [both groups: P <0.001]. For the entire cohort, the actual ETT size was smaller than predicted by the standard Cole formula, with a correlation coefficient of 0.797. Infants with Down syndrome under one year of age were more likely to be on anti-failure medications (64.2% vs. 43.9%, P = 0.011) and have more complex cardiac anomalies (RACHS-1 score) compared to older children. These conditions had not impact on the endotracheal tube size used. The incidence of reintubation was 11.9% in the younger group and 7.0% in the older group, with respiratory causes being the most common reason.
Conclusions:
The Cole formula consistently overestimated the required ETT size for children with Down syndrome undergoing cardiac surgery. While Cole's formula can serve as a general guide, in children with Down syndrome, individual anatomical variations necessitate clinical judgment and adjustments. This highlights the need for improved methods to predict ETT size in this population.
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