Helmet-CPAP safely improves oxygenation in pregnant women with COVID-19 respiratory failure

Administrating continuous positive airway pressure (CPAP) through a helmet (h-CPAP) device safely improves oxygenation in women with moderate-to-severe acute respiratory failure (ARF) due to the coronavirus disease 2019 (COVID-19), a recent study has found.

“H-CPAP was effective in improving oxygenation compared to oxygen therapy, but its role in preventing endotracheal intubation (ETI) still needs to be clarified,” the researchers said. “The application of an h-CPAP trial may allow a maximization of CPAP effectiveness, preventing the inappropriate positive end-expiratory pressure (PEEP) use.”

Forty-one pregnant women were retrospectively assessed, of whom 27 (66 percent) developed hypoxaemic ARF. Ten patients eventually received h-CPAP intervention due to deterioration of gas exchange and/or respiratory distress. CPAP significantly improved arterial oxygen saturation of haemoglobin (SaO₂; p=0.038), arterial partial pressure of oxygen (PaO₂; p=0.033), and the ratio of PaO2 to fractional concentration of oxygen in inspired air (FiO₂; PaO₂/FiO₂: p<0.001). [PLoS One 2021;doi:10.1371/journal.pone.0258754]

Eight of the h-CPAP recipients were deemed to be PEEP responders, all of whom showed good tolerance for h-CPAP. These patients received three cycles per day for a median of 5 days. However, despite the device use, three PEEP responders continued to show deterioration of arterial blood gas (ABG), ultimately requiring ETI and invasive mechanical ventilation.

All patients, including those who required ETI and invasive ventilation, survived COVID-19, and there was no need to deploy extracorporeal circulation oxygenation. By the end of the study, seven women (17.1 percent) were still pregnant, three of whom required h-CPAP and one underwent ETI. No maternal or foetal complications were documented in this subgroup regardless of the respiratory interventions needed.

The remaining 34 women had given birth during the duration of the study, four of whom (11.8 percent) needed emergency caesarean section due to worsening maternal status requiring ETI and mechanical ventilation. One patient also showed worsening foetal condition. The remaining 30 patients gave birth normally, 21 of which were vaginal deliveries.

H-CPAP also proved to be safe, triggering no adverse events, including pneumothorax or haemodynamic instabilities or venous thrombosis of the upper limbs. All women and infants were discharged in good condition.

“Given the paucity of cases described so far, it is impossible to draw definitive conclusions on the efficacy of h-CPAP in preventing ETI in pregnant women and on the prognostic role of PEEP responsiveness,” the researchers said. “Nevertheless, continuous monitoring in an appropriate setting during h-CPAP application should be mandatory to promptly identify early signs of ARF deterioration.”

The small sample size also limited the generalizability of the findings and hindered the identification of predictive factors for respiratory failure in pregnant women on h-CPAP, they added.

“Future studies should aim to clarify the causes of the increased rate of moderate-to-severe ARF in pregnant women during the latest pandemic waves and to better evaluate the prognostic factors associated to ARF deterioration,” the researchers said.