TABLE 2

Prone positioning in non-intubated, coronavirus disease 2019 (COVID-19) patients

First author [ref.]DesignPatients nRespiratory devicePP regimenMain resultsAdverse eventComments
Sun [27]Retrospective analysis631HFNC and NIVUnknownCombined strategy including PP might decrease mortalityBundled intervention
PP regimen undisclosed
Elharrar [28]Prospective feasibility study24COT and HFNC≥3 h, one sessionIncreased PaO2 during PPBack pain (42%)3 patients maintained improvement after resupination
Despres [29]Prospective feasibility study6COT and HFNC1 to 16 hImprove PaO2/FIO2In ICU 3 (50%) patients required intubation
Xu [30]Retrospective case series10HFNC16 h per dayImprove PaO2/FIO2Discomfort and anxiety0 patients required intubation
Ng [31]Prospective case series10COT1 h, 5 times per dayShortening of oxygen weaningMusculoskelatal discomfort and nausea/vomiting8 patients received COVID-19 specific therapies
Damarla [32]Retrospective case series10COT and HFNCAlternate every 2 hImprove SpO2
Decrease dyspnoea/RR
In ICU 2 patients required intubation (most severe, HFNC 0.5 and 0.6)
Reddy [33]Meta-analysis449COT, HFNC and NIVHeterogeneousImprove oxygenation
Decrease RR
Included 15 studies
Sartini [34]Prospective case series15CPAPBased on severity and adherenceImprove SpO2 and PaO2/FIO2
Decrease RR
80% of patients maintain oxygenation improvement after resupination
Coppo [35]Prospective feasibility study56Helmet CPAP≥3 hImprove PaO2/FIO2Discomfort and cough50% of patients maintain PaO2/FIO2 improvement after resupination but no difference on intubation rate
Caputo [36]Observational cohort study50COT5 minImprove SpO2In ED 13 (25%) patients required intubation within 24 h
Thompson [37]Prospective feasibility study25COT1 hImprove SpO2In IMCU 12 (48%) patients required intubation
Patients with an SpO2 ≥95% after 1 h of PP was associated with a lower rate of intubation
Hallifax [38]Retrospective cohort study30HFNC and NIV2 h twice per day,
2 consecutive days
Reduced mortalityIn ICU only 11 patients “fully” prone
Padrão [39]Retrospective cohort study57COT≥4 hDo not reduce intubation rateAccidental removal of i.v. linesOnly COT was used while other respiratory devices might improve outcomes
Ferrando [40]Prospective cohort study55HFNC16 h per dayDo not reduce intubation rateIn ICU did not establish whether was used as a routine or life-saving therapy
Non-prone group also included regimen <16 h per day
Jagan [41]Retrospective analysis40≥1 h, 5 times per day, +1 h overnightDecrease intubation rateRespiratory devices undisclosed
Prone group patient were younger and healthier
PP regimen at patient's discretion

PP: prone positioning; HFNC: high-flow nasal cannula; NIV: noninvasive ventilation; COT: conventional oxygen therapy; PaO2: arterial oxygen tension; FIO2: inspiratory oxygen fraction; ICU: intensive care unit; SpO2: oxygen saturation measured by pulse oximetry; RR: respiratory rate; CPAP: continuous positive airway pressure; ED: emergency department; IMCU: intermediate care unit.