Positive role of continuous positive airway pressure for intensive care unit patients with severe hypoxaemic respiratory failure due to COVID-19 pneumonia: A single centre experience

Abstract

Objectives Continuous positive airway pressure (CPAP) may be a useful treatment strategy for patients with severe COVID-19 pneumonia but its effectiveness in preventing mechanical ventilation is unknown. We aimed to evaluate the outcomes of COVID-19 patients treated with CPAP and determine predictors of CPAP response. Design This was a retrospective observational cohort study. Setting The study took place in the intensive care unit (ICU) at Royal Papworth Hospital (RPH) in Cambridge, UK. Patients We included all consecutive patients with confirmed COVID-19 pneumonia who were transferred from neighbouring hospitals between 14th March and 6th May, 2020 for consideration of ventilatory support. Intervention We instituted the use of CPAP for all patients who arrived in RPH not intubated and were not making satisfactory progress on supplemental oxygen alone. Measurements and main results Of 33 self-ventilating patients included in this study, 22 (66.7%) were male and the mean age was 54 ± 13.23 patients received CPAP. They were more hypoxaemic than those treated with oxygen alone (PaO2/FiO2 ratio; 84.3 ± 19.0 vs 170.0 ± 46.0 mmHg, p = 0.001). There was a significant improvement in PaO2/FiO2 ratio 1–2 hours after CPAP initiation (167.4 ± 49.0 from 84.3 ± 19.0 mmHg, p = 0.001). 14 (61%) patients responded to CPAP and 9 required intubation. There was no difference between these two groups in terms of the severity of baseline hypoxaemia (PaO2/FiO2 ratio; 84.5 ± 16.0 vs 83.9 ± 23.0 mmHg, p = 0.94) but CPAP responders had significantly lower C-reactive protein (CRP) (176 ± 83 vs 274 ± 63 mg/L, p = 0.007), interleukin-6 (IL-6) (30 ± 47 vs 139 ± 148 pg/mL, p = 0.037), and D-dimer (321 ± 267 vs 941 + 1990 ng/mL, p = 0.003). CT pulmonary angiogram was performed in 6 out of 9 intubated patients and demonstrated pulmonary emboli in 5 of them. All patients were discharged from ICU and there were no fatalities. Conclusions In this cohort, CPAP was an effective treatment modality to improve hypoxaemia and prevent invasive ventilation in a substantial proportion of patients with severe respiratory failure. Accepting the small sample size, we also found raised biomarkers of inflammation (CRP and IL-6) and coagulopathy (D-Dimer) to be more useful predictors of CPAP responsiveness than the severity of hypoxaemia, and could help to guide intubation decisions in this clinical setting.

Exploiting Bacteria for Improving Hypoxemia of COVID-19 Patients

“…CPAP is a form of respiratory support that can help patients with respiratory distress and increased oxygen requirements. The objective of CPAP treatment is to augment functional residual capacity, improve oxygenation, increase lung compliance, and possibly avoid intubation to maintain acceptable oxygenation [ 35 ]. That CPAP has significant contraindications is well known, and therefore, any solution to reduce CPAP duration is desirable [ 36 , 37 ].…”

Continuous Positive Airway Pressure (CPAP) in Covid 19 Acute Respiratory Distress Syndrome (ARDS): A Systematic Review

“…There is significant heterogeneity around the definition of CPAP failure. In general, earlier studies in resource rich settings feature early escalation to intubation and ventilation based on parameters such as raised respiratory rate whereas later studies and those in resource poor settings feature continued CPAP despite raised respiratory rate which was shown to be a poor marker of CPAP failure (25,28).…”

“…However, while patients with mild disease who would be expected to do better in terms of survival are included, this study also includes a significant number of patients (65/157 = 41% of total) with a DNI status who would 10. Wozniak et al (2022) (28) This study was a retrospective cohort study conducted at a well-resourced tertiary centre. The sample size of CPAP patients is small (23) but all patients had been referred from neighbouring hospitals for consideration of IMV and most had severe CARDS (mean P a O 2 /FiO 2 84.3 +/-19 mmHg).…”

“…While this is higher than Brusasco et al, it includes patients with mild disease who would have been expected to better in any case. Also, criteria thresholds for CPAP failure differ from Brusasco et al, for example a respiratory rate > 25 is employed rather than > 30 as in Brusasco et al As later studies have shown tachypnea to be a poor discriminator of CPAP failure(25,28), some the patients deemed as CPAP failure in Aliberti et al may have had the potential to recover with IMV.…”

The aerobiology of SARS-CoV-2 in UK hospitals and the impact of aerosol generating procedures

“…Aerosol generating procedures (AGPs) such as non-invasive ventilation (NIV) have been considered essential in providing respiratory support for patients with severe COVID-19 and in reducing the need for invasive ventilation which is associated with higher morbidity and mortality, others such as High Flow oxygen have now been shown to offer no benefit in comparison with conventional oxygen [3][4][5] . Despite improved patient outcomes, AGPs came under increased scrutiny during the severe acute respiratory syndrome (SARS) outbreak of 2003, when observational data suggested AGPs increased the risk of healthcare workers (HCW) acquiring infection 6 .…”