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Table 2 Baseline characteristics of patients on FF-CPAP

From: Continuous positive airway pressure for respiratory support during COVID-19 pandemic: a frugal approach from bench to bedside

  All patients (n = 85) FF-CPAP alone (n = 31) FF-CPAP followed by intubation (n = 54) P value
Demographic data
 Age, year 60 (50–68) 59 (46–64) 60 (53–70) 0.10
 Female sex, n (%) 14 (16.5) 5 (16.1) 9 (16.7) > 0.99
 Body mass index, kg/m2 28.5 (24.5–31.1) 28.6 (24.7–30.7) 28.5 (24.4–31.9) 0.84
Medical history
 Current smoking, n (%) 5 (5.9) 2 (6.5) 3 (5.6)  > 0.99
 Chronic respiratory disease, n (%) 8 (9.4) 2 (6.5) 6 (11.1) 0.71
 Chronic cardiac disease, n (%) 8 (9.5) 4 (13.3) 4 (7.4) 0.45
 Chronic renal disease, n (%) 9 (10.6) 3 (9.7) 6 (11.1) > 0.99
 Cancer, n (%) 9 (10.7) 2 (6.7) 7(13.0) 0.48
Treatment prior to hospital admission
 ACEI, n (%) 19 (22.4) 6 (19.4) 13 (24.1) 0.79
 ARB, n (%) 14 (16.5) 3 (9.7) 11 (20.4) 0.24
 Corticosteroids, n (%) 8 (9.4) 3 (9.7) 5 (9.3) > 0.99
 NSAI, n (%) 3 (3.5) 1 (3.2) 2 (3.7) > 0.99
Symptoms potentially related to COVID-19
 Fever, n (%) 72 (84.7) 28 (90.3) 44 (81.5) 0.36
 Cough, n (%) 64 (75.3) 24 (77.4) 40 (74.1) 0.80
 Dyspnea, n (%) 67 (78.8) 27 (87.1) 40 (74.1) 0.18
 Malaise, n (%) 5 (6.0) 2 (6.5) 3 (5.7) > 0.99
 Rhinorrhea, n (%) 5 (5.9) 1 (3.2) 4 (7.4) 0.65
 Headache, n (%) 12 (14.1) 7 (22.6) 5 (9.3) 0.11
 Diarrhea, n (%) 29 (34.1) 14 (45.2) 15 (27.8) 0.15
 Vomiting, n (%) 10 (11.8) 6 (19.4) 4 (7.4) 0.16
 Myalgia, n (%) 34 (40) 14 (45.2) 20 (37) 0.50
 Chest pain, n (%) 4 (4.7) 1 (3.2) 3 (5.6) > 0.99
Vital signs prior to FF-CPAP initiation
 Oxygen flow rate, L/min 15 (9–15) 12 (9–15) 15 (9–15) 0.11
 Respiratory rate, breaths/min 34 (28–40) 30 (25–35) 35 (30–40) 0.009
 Heart rate, beats/min 89 (79–100) 82 (75–95) 91 (85–100) 0.028
 Mean blood pressure, mmHg 98 (89–106) 101 (93–104) 97 (88–107) 0.55
Arterial blood gases prior to FF-CPAP initiation
 pH 7.45 (7.42–7.47) 7.45 (7.42–7.48) 7.45 (7.42–7.47) 0.30
 Bicarbonates, mmol/L 24.5 (22.3–26.3) 23.3 (21.9–26.1) 24.7 (23.6–26.8) 0.17
 Lactate, mmol/L 1.3 (1.1–1.6) 1.5 (1.1–1.9) 1.3 (1.0–1.6) 0.37
 PaO2, mmHg 73 (61–91) 71 (59–94) 74 (61–89) > 0.99
 PaCO2, mmHg 35 (31–38) 33 (30–38) 36 (33–39) 0.15
 PaO2/FiO2a, mmHg 160 (115–258) 148 (111–248) 163 (115–277) 0.55
 ROX indexb 4.86 (3.67–6.37) 5.61 (4.54–7.21) 4.44 (3.55–5.70) 0.013
Percentage of involved parenchyma on CT-scan before FF-CPAP initiation (n = 65)
 ≤ 50%, n (%) 27 (41.8) 9 (37.5) 18 (43.9) 0.79
 > 50%, n (%) 38 (58.5) 15 (62.5) 23 (56.1) 0.79
  1. aFiO2 was estimated as follows [5]: FiO2 (%) = 21 + [3 × oxygen flow rate (L/min)]
  2. bROX index was computed as follows: ROX index = (SpO2/FiO2)/respiratory rate, the FiO2 being estimated as described above
  3. FF-CPAP filter frugal continuous positive airway pressure (see text for definition), COPD chronic obstructive pulmonary disease, ACEI angiotensin-converting enzyme inhibitor, ARB angiotensin II receptor blocker, NSAI non-steroidal anti-inflammatory drug within the 7 days before hospital admission