Distances from vocal cords to mid-trachea for optimizing endotracheal tubes depth markers according to gestational age

Ultrasound assessment of endotracheal tube depth in neonates: a prospective feasibility study

OBJECTIVE

To examine the reliability of a novel ultrasound (US) method for assessment of endotracheal tube (ETT) position in neonates.

DESIGN

Prospective, observational, single-centre, feasibility study.

SETTING

Level III neonatal intensive care unit.

PATIENTS

Term and preterm neonates requiring endotracheal intubation.

INTERVENTION

US measurement of the ETT tip to right pulmonary artery (RPA) distance was used to determine ETT position according to one-fourth to three-fourths estimated tracheal length for weight. US demonstration of pleural sliding and diaphragmatic movement was also assessed. Chest radiography (CXR) was performed following each intubation.

MAIN OUTCOME MEASURES

Agreement between US assessment of ETT tip position and CXR served as the gold standard. Sensitivity, specificity, positive and negative predictive values for each US method and correlation between ETT tip to RPA distance on US, and ETT tip to carina distance on CXR were assessed.

RESULTS

Forty-two US studies were performed on 33 intubated neonates. US evaluation of ETT-RPA distance identified 100% of ETTs positioned correctly: 77% deep and 80% high, demonstrating strong agreement with CXR (kappa=0.822). Sensitivity was 78%, specificity 100%, positive predictive value 100% and negative predictive value 86%. US ETT-RPA distance strongly correlated with CXR ETT-carina distance (r=0.826). No significant agreement was found between CXR and US assessment of pleural sliding and diaphragmatic movement. No adverse events were encountered during US scans.

CONCLUSION

US evaluation of ETT-RPA distance demonstrated excellent accuracy for determining ETT position in neonates compared with CXR. More research is needed to support its feasibility in clinical settings.

Strategies to Improve Neonatal Intubation Safety by Preventing Endobronchial Placement of the Tracheal Tube-Literature Review and Experience at a Tertiary Center

Unintended endobronchial placement is a common complication of neonatal tracheal intubation and a threat to patient safety, but it has received little attention towards decreasing its incidence and mitigating associated harms. We report on the key aspects of a long-term project in which we applied principles of patient safety to design and implement safeguards and establish a safety culture, aiming to decrease the rate of deep intubation (beyond T3) in neonates to <10%. Results from 5745 consecutive intubations revealed a 47% incidence of deep tube placement at baseline, which decreased to 10-15% after initial interventions and remained in the 9-20% range for the past 15 years; concurrently, rates of deep intubation at referring institutions have remained high. Root cause analyses revealed multiple contributing factors, so countermeasures specifically aimed at improving intubation safety should be applied before, during, and immediately after tube insertion. Extensive literature review, concordant with our experience, suggests that pre-specifying the expected tube depth before intubation is the most effective and simple intervention, although further research is needed to establish accurate and accepted standards for estimating the expected depth. Presently, team training on intubation safety, plus possible technological advances, offer additional options for safer neonatal intubations.

Tracheal Length Measurement in Intubated Neonates to Guide the Design and Use of Endotracheal Tube Glottic Depth Markings

Background: Data on neonatal tracheal length are needed to inform the standardization of safety features for endotracheal tubes (ETTs) such as glottic depth markings. Laryngotracheal airway measurements are available from digital imaging in infants and children but not in neonates. We aimed to determine the tracheal length (TL) of intubated preterm and term neonates. Methods: An observational study was performed on 57 neonates of 22–42 weeks’ gestation and <1 week of age. Two clinicians independently reviewed 153 digital chest radiographs to determine the carina position and TL. TL was measured from carina to mid-C4 (cricoid level). We analyzed interrater agreement (within 0.5 vertebral levels) on the position of the carina and TL. TL was plotted as a function of gestational age and weight, using graphical and regression analyses. Results: Carina position ranged from T3 to T5.5, with an interrater agreement of 95%. On image pairs concordant for carina position, TL determinations were virtually identical between readers (mean difference 0.1 mm, 95% CI −0.5–0.6 mm). Average mid-tracheal length overlies the body of T1. In infants aged less than 32 weeks’ gestation, the mid-trachea lies <20 mm from the carina or the larynx. TL linearly correlates with gestational age, but correlation with birthweight best fits a segmented regression with a node at 1 kg. Conclusions: The functional length of the laryngotracheal airway can be reliably measured in sick neonates. It correlates well with gestational age and birthweight, and this information can inform the redesign of ETT markings to promote the safer use of these devices.

Comparison of tracheoscopy and portable chest X-Ray in the evaluation of infant tracheostomy tube position

OBJECTIVE

To compare tracheoscopy and chest radiograph measurements of tracheostomy tube position in infants.

STUDY DESIGN

Retrospective chart review.

SETTING

Otolaryngology Department at Penn State Milton S. Hershey Medical Center.

SUBJECTS AND METHODS

All cases of pediatric patients who underwent tracheotomy at less than 1 year of age from 2014 to 2019 were reviewed. Patients were included if they had both intraoperative measurement of tracheostomy tube position relative to the carina by tracheoscopy and postoperative chest radiograph. Documented intraoperative findings were compared to measurements made on chest radiograph by an attending radiologist blinded to the intraoperative measurements.

RESULTS

The study included 66 patients; 30 patients (14:16, M:F) had available data. The mean distance from the distal tracheostomy tube to the carina measured by tracheoscopy was 8.88 mm (range, 3.5-20 mm) and measured radiographically was 11.71 mm (range, 2.4-23.3 mm). The mean difference between the measurements was 2.82 mm (p-value = 0.016). Ninety percent (n = 27) of patients had measurements that differed by greater than 2 mm; 53% (n = 16) had measurements that differed by 5 mm and 1% (n = 3) had measurements differing by greater than 10 mm.

CONCLUSION

In the infant population, significant discrepancy was found between direct tracheoscopy and chest radiograph measurements of the tracheostomy tube position. Measurements obtained by chest radiographs tend to overestimate the relative distance of the distal tracheostomy tube to the carina as compared to that of tracheoscopy. Clinical decisions regarding changes to tracheostomy tube sizes should mostly rely on tracheoscopy performed with the patient supine.