Helmet CPAP to treat hypoxic pneumonia outside the ICU: an observational study during the COVID-19 outbreak

Abstract

Background Respiratory failure due to COVID-19 pneumonia is associated with high mortality and may overwhelm health care systems, due to the surge of patients requiring advanced respiratory support. Shortage of intensive care unit (ICU) beds required many patients to be treated outside the ICU despite severe gas exchange impairment. Helmet is an effective interface to provide continuous positive airway pressure (CPAP) noninvasively. We report data about the usefulness of helmet CPAP during pandemic, either as treatment, a bridge to intubation or a rescue therapy for patients with care limitations (DNI). Methods In this observational study we collected data regarding patients failing standard oxygen therapy (i.e., non-rebreathing mask) due to COVID-19 pneumonia treated with a free flow helmet CPAP system. Patients’ data were recorded before, at initiation of CPAP treatment and once a day, thereafter. CPAP failure was defined as a composite outcome of intubation or death. Results A total of 306 patients were included; 42% were deemed as DNI. Helmet CPAP treatment was successful in 69% of the full treatment and 28% of the DNI patients (P < 0.001). With helmet CPAP, PaO2/FiO2 ratio doubled from about 100 to 200 mmHg (P < 0.001); respiratory rate decreased from 28 [22–32] to 24 [20–29] breaths per minute, P < 0.001). C-reactive protein, time to oxygen mask failure, age, PaO2/FiO2 during CPAP, number of comorbidities were independently associated with CPAP failure. Helmet CPAP was maintained for 6 [3–9] days, almost continuously during the first two days. None of the full treatment patients died before intubation in the wards. Conclusions Helmet CPAP treatment is feasible for several days outside the ICU, despite persistent impairment in gas exchange. It was used, without escalating to intubation, in the majority of full treatment patients after standard oxygen therapy failed. DNI patients could benefit from helmet CPAP as rescue therapy to improve survival. Trial Registration: NCT04424992

Clinical Trends Among U.S. Adults Hospitalized With COVID-19, March to December 2020

“…Several studies have shown improved outcomes with prone positioning ( 37 ) and use of noninvasive ventilatory support in lieu of invasive mechanical ventilation ( 11 , 15 , 38 ) for patients with acute respiratory failure associated with COVID-19. Decreasing use of invasive mechanical ventilation may have also lessened the need for ICU-level care because other types of respiratory support could be delivered in non-ICU settings ( 39 ).…”

Noninvasive respiratory support and patient self-inflicted lung injury in COVID-19: a narrative review

“… 107 Helmet CPAP treatment presents a success rate greater than 60% 108 and has been considered as a rescue therapy to improve survival. 109 One RCT is ongoing to evaluate the impact of helmet CPAP in COVID-19 pneumonia patients. 110 …”

The use of head helmets to deliver noninvasive ventilatory support: a comprehensive review of technical aspects and clinical findings

“…In other words, as shown in Fig. 2 , positive pressure not only improved oxygenation but also allowed better stratification of patient severity [ 40 ]. Some authors also suggested that an incremental PEEP trial might allow a PEEP selection with optimized oxygenation while avoiding haemodynamic complications [ 41 ].…”

“…The oxygenation increase was more pronounced in patients who could be successfully treated with helmet CPAP without escalation to intubation (white boxes, P = 0.002 for interaction between the CPAP effect and outcome). Reproduced under Creative Common licence from [ 40 ] …”