Previous Abstract | Next Abstract
Printable Version
October 03, 2020
10/3/2020 3:00:00 PM - 10/3/2020 4:00:00 PM
Room Virtual
Triaging Covid-19 Patients In The Emergency Room Using A Respiratory Volume Monitor
Vimal Desai, M.D., Dicky Shah, M.D., Jeffrey M. Cohen, M.D., Shawn R. Winnick, M.D., Gonzalo Custodio, B.S.N., Jennifer Naughton, B.A., Sangita Nichols, B.S., John Sang Lee, M.D., Chunyuan Qiu, M.D., M.S., John Naughton, B.S.
Kaiser Permanente Baldwin Park, Baldwin Park, California, United States
Disclosures: V. Desai: None. D. Shah: None. J.M. Cohen: None. S.R. Winnick: None. G. Custodio: None. J. Naughton: None. S. Nichols: None. J. Lee: None. C. Qiu: None. J. Naughton: None.
Introduction: As US hospitals experience a surge of patients during the COVID-19 pandemic, decisions on triaging patients requires fast, affordable and dependable measurements to appropriately assign hospital resources. Thus far, patient age, comorbidities, respiratory rate, and pulse oximetry with or without arterial blood gas data, have been used to identify patients requiring hospital admission. Hyperventilation is an early indicator of viral pneumonia which is not directly measured by standard clinical evaluation. Here we present the use of a respiratory volume monitor (RVM), which non-invasively measures minute ventilation (MV), as a leading indicator and decision support tool for triage of patients with COVID-19 symptoms in the emergency department (ED) of Kaiser Permanente Baldwin Park Medical Center.

Methods: Patients presenting to the ED were monitored with a RVM (ExSpiron 1Xi, Respiratory Motion Inc, Watertown MA) via a single use L-shaped electrode padset placed at the sternal notch, xiphoid and mid-axillary line at the level of the xiphoid. MV, measured as a percentage of predicted MV (MVPRED) for each patient based on height, weight and gender, was used to quantify hyperventilation and inform admittance decisions along with clinical observations, pulse oximetry and, when available, chest X-rays. Patient course was tracked throughout hospital stay.

Results: Six patients presented to the ED with viral pneumonia symptoms, with five testing positive for COVID-19. A 63 yo female had MV >300%, requiring immediate admission to the ICU where she was intubated (Fig 1A). Likewise, a 58 yo male had MV >250% and was admitted to the ICU, where he deteriorated requiring BiPAP and eventual intubation. Another two patients (55 yo male and 26 yo female) had MV in the range of 200-250%, but maintained adequate oxygenation (>92%) with 2L nasal cannula throughout and transitioned to room air with discharge within a week (Fig 1B-C). Finally, two patients (65 and 80 yo males) had MV <200%, but were admitted based on other risk factors and placed on 2L nasal cannula. Both patients experienced an uneventful course with adequate oxygenation and quickly transitioned to room air. Based on preliminary findings, we have implemented a new protocol to drive patient triage (Fig 1D). Briefly, patients breathing below 200% of MVPRED should be considered for discharge, while those above 300% require ICU level care and may require intubation. Depending on MV and oxygenation patients can be admitted to the floor (MV: 200-250% and SpO2 > 92%) for further monitoring with the RVM or the step down unit or ICU (MV: 250-300% or SpO2 <92%).

Conclusions: With or without real time PCR test results, COVID-19 admission from ED to the ICU or to the general hospital floor is often based on clinical observation and supplemental evidence from chest X-rays and pulse oximetry, which are not direct measurements of ventilation and lagging indicators of the evolution of viral pneumonia. Pulse oximetry can produce a delayed response, remaining within normal range despite deterioration of respiratory function. Conversely, the RVM provides direct measurements of respiratory status, and can identify and quantify hyperventilation and increased work of breathing due to evolving pneumonia sooner than clinical assessment. As opposed to strict age and pulse oximetry criteria, the RVM can be used to differentiate between patients with mild symptoms and those with deteriorating respiratory status that require escalating care such as observation in the hospital, ICU admission or ventilator support.
Figure 1

Copyright © 2020 American Society of Anesthesiologists