447 - Developing a Smart Endotracheal Tube for Pediatric Use

Poster Number: 447
Publication Number: 447.228

Thomas Nienaber, University of Arkansas for Medical Sciences College of Medicine, Little Rock, AR, United States; Sarah Perez, UAMS, Little Rock, AR, United States; Adria Abella Villafranca, UAMS, LITTLE ROCK, AR, United States; Krista Stephenson, University of Arkansas for Medical Sciences, Little Rock, AR, United States; Joseph Sanford, University of Arkansas for Medical Sciences College of Medicine, Little Rock, AR, United States; Kevin W. Sexton, UAMS, Little Rock, AR, United States

Background: Uncuffed endotracheal tubes have been used in pediatric patients following concern for complications surrounding the endotracheal tube (ETT) cuff. It is postulated that high pressure causes venous blockade, leading to edema and/or necrosis causing airway edema, extubation failure, subglottic stenosis, etc. Current devices have not decreased complications significantly, potentially due to the cuff pressure remaining above central venous pressure.

Objective: We hypothesize that measuring and decreasing pressure exerted by the cuff will decrease tracheal mucosal injury.

Design/Methods: A prototype endotracheal tube was developed, integrating a sensor that can detect changes in pressure of the cuff and leak around the cuff. 16 New Zealand White (NZW) rabbits were equally randomized into 2 groups, comparing standard cuffed ETTs to our prototype. Intubation was performed with video assistance. ETT cuffs were inflated to eliminate leak by auscultation in the control group and based on signal output in the intervention group. Both groups were ventilated for 2 hours and vital signs were monitored. Subsequently the trachea was excised, fixed in formalin, and examined histologically. The percent surface area preserved was evaluated by generating two masks per slide, one covering all the undamaged area and the second one covering only the damaged area, and counting the colored pixels for each mask using a Python script.

Results: With 8 rabbits in each group, 3 died in the control group, 2 died in the intervention group, due to State laboratory diagnosed pre-existing illness. In the control group, 50% surface area of the trachea mucosa was intact, compared to 68% in the intervention group, which is greater than our hypothesized difference of 15%. Analysis of the waveform data generated yielded the surprising results of our ability to use the sensor to monitor physiologic parameters, including respiratory rate, heart rate, and possibly blood pressure. The data also suggest that cuff shape may be as important as cuff pressure for creating a seal in the trachea and a dampening cuff pressure design is better compared to the traditional cuff design.Conclusion(s): Our prototype endotracheal tube decreases tracheal mucosal injury and may provide physiological monitoring capabilities. Further work needs to be done to determine the long term outcomes of this device.
Percentage of trachea affected by groupTable 1. Results of affected trachea based on histology and pixel counted masking
Control (left) vs intervention (right)Image 1. Manual masking demonstrating hematoxylin and eosin staining of tracheal mucosa.