Use of Respiratory Acoustic Monitor for Postoperative Monitoring in Children

Recording vital signs is the standard of care for all patients on the hospital wards after surgery to detect respiratory and cardiovascular depression before serious complications ensue. Of all the vital signs, an altered respiratory rate is one of the best predictors of respiratory depression, cardiac arrest, and admission to the ICU. Despite its clinical importance, respiration rate is the last core vital sign without a reliable and continuous monitoring method that patients can easily tolerate. Besides manually counting respiration, the two standards of care for monitoring respiratory rate: thoracic impedance pneumography (Tl) and capnometry, fall short of monitoring respiratory rate in a reliable and tolerable fashion. These limitations have lead the Masimo corporation to develop a bio-acoustic respiratory rate monitor (RAM) to non-invasively convert acoustical airflow patterns detected from the surface of the neck into respiratory rate measurements using an innovative adhesive sensor with an integrated acoustic transducer. The accuracy and reliability of RAM has not been evaluated in the in-patient surgical wards of the pediatric population. We compared the reliability and accuracy of RAM and Tl monitoring in postoperative pediatric patients at risk of adverse respiratory events while also assessing the tolerance of the RAM sensor and ECG pads (Tl). We recruited thirty children from 2 to 16 years old (mean age 6.58) who had a tonsillectomy due to OSA at Children's Medical Center (Dallas, TX). Following arrival to the inpatient care unit an adhesive RAM sensor and pediatric Sp02 finger sensor were connected along with standard Tl ECG pads. Vital signs were recorded from the RAM sensors and Tl, and a manual RR was obtained every 2-hours until patient discharge. Data from these 30 patients were combined with 30 patients recruited from Cincinnati Children's Hospital (Cincinnati, OH) for statistical analysis. The three measurement methods (Manual, RAM, and Tl) were found to be significantly different {p=0.0255). RAM and manual measurements of RR were on the average not significantly different (p=0.0255) with a higher correlation coefficient (0.5851), whereas Tl and manual RR measurements of RR are significantly different (p=0.0066) with a lower correlation coefficient (0.4898). The average RR difference between RAM and manual was 0.17 ± 6.81, and the average RR difference for Manual vs Tl was 1.39 ft 10.63. Additional results suggest that RAM may prove a more accurate and tolerable method for monitoring pediatric respiratory rate and respiratory depression, cardiac arrest, and admission to the ICU than the standard of care methods currently in use in hospitals across the country.