Abstract 108: Work of Breathing Scale to Assess Need of Intubation in Covid-19 Pneumonia

Abstract

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.

Vital signs and work of breathing assessment in the emergency department as predictor for acute respiratory failure in COVID-19 pneumonia

“…Hence, the early recognition of ARF in the emergency department (ED) can be accomplished by measuring the patient's vital signs and work of breathing. The accurate measurement of vital signs and work of breathing can indicate the patient's outcomes, such as by predicting the risk of patient deterioration [12,13]. Hence, the early identification of patients whose vital signs indicate an unfavourable progno-sis could facilitate their prompt referral to a more appropriate hospital.…”

“…Vital signs and work of breathing measurements are important parameters in determining patients at risk of deterioration [12,13]. Vital signs, including respiratory rate (RR), heart rate (HR), oxygen saturation, blood pressure, body temperature and work of breathing, such as nasal flaring, and the contraction of sternocleidomastoids and abdominal muscles, are easy to detect, but valuable in assessing patients' clinical responses and risk of respiratory muscle fatigue, which can lead to hypoventilation and ARF [14].…”