Are preformed endotracheal tubes appropriately designed for pediatric patients?

BACKGROUND: The aim of the study was to examine different brands of preformed oral and nasal endotracheal tubes (ETT) and to assess whether the bend placement gave acceptable guidance for ETT depth positioning in children. METHODS: The distance from the vertex of the bend to the tip (bend-to-tip distance) of seven brands of preformed oral and nasal ETTs were measured. Front teeth-to-carina (FTC) and nares-to-carina (NC) distance data from orally (0-19 years) and nasally (0-8 years) intubated children were used to assess the risk of endobronchial intubation if a preformed ETT had been placed with its bend at the front teeth or nares. RESULTS: While the bend-to-tip distance of a cuffed oral preformed ETT only differed by 0-1 cm from a same size ETT from another brand, uncuffed oral ETTs differed by 0-4 cm. The bend-to-tip distance of cuffed and uncuffed ETTs of the same brand and size differed by 0-3 cm. Had preformed cuffed oral ETTs been placed with their bends at the front teeth in children of the FTC reference group, endobronchial intubation would have occurred in 0-27% of the patients, depending on the size and brand of the used ETT. In contrast to oral ETTs, the bend-to-tip distance of cuffed nasal ETTs differed more (0-5.5 cm) between brands, and uncuffed nasal ETTs less (0-3 cm). Also, the bend-to-tip distance of a cuffed nasal ETT was consistently greater (2-9 cm) than that of a same brand and size nasal uncuffed ETT. Had a preformed cuffed nasal ETT been placed with its bend at the nares in the NC reference group, 50-100% of the patients would have been endobronchially intubated. CONCLUSION: The bend-to-tip distance of preformed ETTs varies between brands, especially for nasal tubes. Some preformed tubes are not well suited for routine use in children. There is a high risk for accidental endobronchial intubation if a cuffed preformed ETT is positioned with its bend at the front teeth or nares in a young child. ETT tube tip position needs to be carefully controlled when a preformed ETT is used in a child.

Accuracy of Age-Based Formula to Predict the Size and Depth of Cuffed Oral Preformed Endotracheal Tubes in Children Undergoing Tonsillectomy.

OBJECTIVES: To retrospectively investigate the reliability of the age-based formula, year/4 + 3.5 mm in predicting size and year/2 + 12 cm in predicting insertion depth of preformed endotracheal tubes in children and correlate these data with the body mass index. PATIENTS AND METHODS: Patients were classified into 4 groups according to their nutritional status: thinness, normal weight, overweight, and obesity; we then retrospectively compared the actual size of endotracheal tube and insertion depth to the predicting age-based formula and to the respective bend-to-tip distance of the used preformed tubes. RESULTS: Altogether, 300 patients were included. The actual endotracheal tube size corresponded with the Motoyama formula (64.7%, 90% CI: 60.0-69.1), except for thin patients, where the calculated size was too large (0.5 mm). The insertion depth could be predicted within the range of the bend-to-tip distance and age-based formula in 85.0% (90% CI: 81.3-88.0) of patients. CONCLUSION: Prediction of the size of cuffed preformed endotracheal tubes using the formula of Motoyama was accurate in most patients, except in thin patients (body mass index < -2 SD). The insertion depth of the tubes was mostly in the range of the age-based-formula to the bend-to-tip distance.

Estimation of optimal nasotracheal tube depth in adult patients.

BACKGROUND: The aim of this study was to estimate the optimal depth of nasotracheal tube placement. METHODS: We enrolled 110 patients scheduled to undergo oral and maxillofacial surgery, requiring nasotracheal intubation. After intubation, the depth of tube insertion was measured. The neck circumference and distances from nares to tragus, tragus to angle of the mandible, and angle of the mandible to sternal notch were measured. To estimate optimal tube depth, correlation and regression analyses were performed using clinical and anthropometric parameters. RESULTS: The mean tube depth was 28.9 ± 1.3 cm in men (n = 62), and 26.6 ± 1.5 cm in women (n = 48). Tube depth significantly correlated with height (r = 0.735, P < 0.001). Distances from nares to tragus, tragus to angle of the mandible, and angle of the mandible to sternal notch correlated with depth of the endotracheal tube (r = 0.363, r = 0.362, and r = 0.546, P < 0.05). The tube depth also correlated with the sum of these distances (r = 0.646, P < 0.001). We devised the following formula for estimating tube depth: 19.856 + 0.267 × sum of the three distances (R2 = 0.432, P < 0.001). CONCLUSION: The optimal tube depth for nasotracheally intubated adult patients correlated with height and sum of the distances from nares to tragus, tragus to angle of the mandible, and angle of the mandible to sternal notch. The proposed equation would be a useful guide to determine optimal nasotracheal tube placement.

Endotracheal tubes: old and new.

The development and evolution of the endotracheal tube (ETT) have been closely related to advances in surgery and anesthesia. Modifications were made to accomplish many tasks, including minimizing gross aspiration, isolating a lung, providing a clear facial surgical field during general anesthesia, monitoring laryngeal nerve damage during surgery, preventing airway fires during laser surgery, and administering medications. In critical care management, ventilator-associated pneumonia (VAP) is a major concern, as it is associated with increased morbidity, mortality, and cost. It is increasingly appreciated that the ETT itself is a primary causative risk for developing VAP. Unfortunately, contaminated oral and gastric secretions leak down past the inflated ETT cuff into the lung. Bacteria can also grow within the ETT in biofilm and re-enter the lung. Modifications to the ETT that attempt to prevent bacteria from entering around the ETT include maintaining an adequate cuff pressure against the tracheal wall, changing the material and shape of the cuff, and aspirating the secretions that sit above the cuff. Attempts to reduce bacterial entry through the tube include antimicrobial coating of the ETT and mechanically scraping the biofilm from within the ETT. Studies evaluating the effectiveness of these modifications and techniques demonstrate mixed results, and clear recommendations for which modification should be implemented are weak.