Feasibility and physiological effects of prone positioning in non-intubated patients with acute respiratory failure due to COVID-19 (PRON-COVID): a prospective cohort study

Abstract

Background The COVID-19 pandemic is challenging advanced health systems, which are dealing with an overwhelming number of patients in need of intensive care for respiratory failure, often requiring intubation. Prone positioning in intubated patients is known to reduce mortality in moderate-to-severe acute respiratory distress syndrome. We aimed to investigate feasibility and effect on gas exchange of prone positioning in awake, non-intubated patients with COVID-19-related pneumonia. MethodsIn this prospective, feasibility, cohort study, patients aged 18-75 years with a confirmed diagnosis of COVID-19related pneumonia receiving supplemental oxygen or non-invasive continuous positive airway pressure were recruited from San Gerardo Hospital, Monza, Italy. We collected baseline data on demographics, anthropometrics, arterial blood gas, and ventilation parameters. After baseline data collection, patients were helped into the prone position, which was maintained for a minimum duration of 3 h. Clinical data were re-collected 10 min after prone positioning and 1 h after returning to the supine position. The main study outcome was the variation in oxygenation (partial pressure of oxygen [PaO 2 ]/fractional concentration of oxygen in inspired air [FiO 2 ]) between baseline and resupination, as an index of pulmonary recruitment. This study is registered on ClinicalTrials.gov, NCT04365959, and is now complete. Findings Between March 20 and April 9, 2020, we enrolled 56 patients, of whom 44 (79%) were male; the mean age was 57•4 years (SD 7•4) and the mean BMI was 27•5 kg/m² (3•7). Prone positioning was feasible (ie, maintained for at least 3 h) in 47 patients (83•9% [95% CI 71•7 to 92•4]). Oxygenation substantially improved from supine to prone positioning (PaO 2 /FiO 2 ratio 180•5 mm Hg [SD 76•6] in supine position vs 285•5 mm Hg [112•9] in prone position; p<0•0001). After resupination, improved oxygenation was maintained in 23 patients (50•0% [95% CI 34•9-65•1]; ie, responders); however, this improvement was on average not significant compared with before prone positioning (PaO 2 /FiO 2 ratio 192•9 mm Hg [100•9] 1 h after resupination; p=0•29). Patients who maintained increased oxygenation had increased levels of inflammatory markers (C-reactive protein: 12•7 mg/L [SD 6•9] in responders vs 8•4 mg/L [6•2] in non-responders; and platelets: 241•1 × 10³/µL [101•9] vs 319•8 × 10³/µL [120•6]) and shorter time between admission to hospital and prone positioning (2•7 days [SD 2•1] in responders vs 4•6 days [3•7] in non-responders) than did those for whom improved oxygenation was not maintained. 13 (28%) of 46 patients were eventually intubated, seven (30%) of 23 responders and six (26%) of 23 non-responders (p=0•74). Five patients died during follow-up due to underlying disease, unrelated to study procedure. Interpretation Prone positioning was feasible and effective in rapidly ameliorating blood oxygenation in awake patients with COVID-19-related pneumonia requiring oxygen supplementation. The effect was maintained after resupina...

Awake Prone Positioning Does Not Reduce the Risk of Intubation in COVID-19 Treated with High-Flow Nasal Oxygen Therapy. A Multicenter, Adjusted Cohort Study

“…All tests were two-sided, and a P-value < 0.05 was considered statistically signi cant. All analyses were performed with STATA version 16.…”

“…Other adjunctive techniques, such as awake-PP, have been widely used in combination with oxygen therapy, NIV or HFNO to correct hypoxemia and avoid the need for invasive MV. [11][12][13][14][15][16] The bene ts of prone positioning in ARDS patients have been well established. By rearrangement of the vertical transpulmonary pressure gradients, prone positioning favors lung recruitment improving V/Q mismatch by decreasing shunt.…”

“…However, no differences in the need for intubation were found between responders and non-responders (26% vs. 30%). 16 Taken together all these small studies -that barely exceed a hundred of patients-, in patients managed with non-invasive ventilatory support methods, awake-PP was differently applied both in length and frequency. These issues make the interpretation of their ndings and the comparison with our analysis extremely di cult.…”

“…10 Several studies have shown that the combination of awake-PP and HFNO or non-invasive ventilation (NIV) is feasible in patients with severe COVID-19 pneumonia, resulting in an increase in oxygenation or a decrease in the respiratory rate and/or dyspnea. [11][12][13][14][15][16] However, to date, it has not been established whether the combination of HFNO plus awake-PP could prevent the need for invasive MV and decrease the need of ICU resources in COVID-19 patients with ARF. We performed this large multicenter adjusted cohort study to investigate those issues.…”

COVID-19: What Can Iodine Maps From Perfusion CT Teach US? A Prospective Cohort Study.

“…In type-L pattern, areas of injured lung parenchyma show hyperperfusion secondary to loss of compensatory hypoxic pulmonary vasoconstriction (vasoplegia), resulting in high perfusion to areas of hypoventilated lung and an abnormally low V/Q ratio; while areas of apparently normal lung parenchyma show hypoperfusion that results in an abnormally high V/Q ratio. Changes in vascular resistance lead to a net shunt or steal of vascular ow towards areas of non-aerated lung, which is supported by the good clinical response to prone position that has been described in patients with COVID-19 (18).…”