Abstract 108: Work of Breathing Scale to Assess Need of Intubation in Covid-19 Pneumonia
COVID-19 pneumonia presents in most patients with significant hypoxemia but without substantial impairment of lung compliance that would increase the work of breathing (WOB) to levels requiring invasive mechanical ventilation. Thus, the ability to assess the WOB independent of the oxygen needs could help guide management and possibly avoid intubation. We previously developed and implemented in our ICU a WOB scale based on respiratory physiology ranging from 1 to 7 by assigning points to the respiratory rate level and the use of respiratory accessory muscles. We analyzed the use of our WOB scale in 10 patients admitted to our ICU with severe COVID-19 pneumonia. All patients had radiographic evidence of extensive lung disease with significant hypoxemia and multiple risk factors associated with poor outcome. Hypoxemia was successfully managed using high-flow nasal cannula. The WOB level was measured every 4 hours. The maximum WOB was 4.3 ± 0.9, contributed primarily by the respiratory rate with a score of 3.6 ± 0.5 but with infrequent use of respiratory accessory muscles. All 10 patients survived without need of intubation. For comparison, three other patients who needed intubation had a maximal work of breathing within the preceding 24 hours of 5.3 ± 1.2 with a respiratory rate score of 3.7 ± 0.6, as in non-intubated patients, but with more often use of respiratory accessory muscles. Our data suggest that patients with COVID-19 pneumonia can be supported for extended periods using HFNC despite tachypnea provided there is only infrequent use of respiratory accessory muscles, corresponding to a WOB scale ≤ 4, prompting closer assessment for possible intubation when WOB > 4. This approach would be especially advantageous under conditions of high disease intensity when avoidance of intubation is likely to result in a better outcome.