Background
Methods
Settings and patients
Study protocol and data collection
Ventilation settings
Study outcomes
Statistical analysis
Results
Patient characteristics
Characteristics | Overall cohort n = 265 |
---|---|
Age—years | 64 ± 14 (62–66) |
Men/women—n (%) | 172 (65%) / 93 (35%) |
Body mass index—kg/m2 | 31 ± 15 (29–32) |
Chronic disease—n (%) | |
COPD | 55 (21%) |
Chronic respiratory failure | 26 (10%) |
Chronic heart failure | 34 (13%) |
SAPS-2 at ICU admission | 59 ± 19 (56–61) |
SOFA at inclusion | 9 ± 3 (8–9) |
Reason for ICU admission—n (%) | |
Medical | 245 (92%) |
Surgical | 20 (8%) |
Acute organ failure at inclusion—n (%) | 178 (67%) |
Hemodynamic | 122 (46%) |
Kidney | 57 (22%) |
Neurologic | 42 (16%) |
Heart | 25 (9%) |
Liver | 22 (8%) |
Hematologic | 9 (3%) |
Main reason for MV—n (%) | |
Acute respiratory failure | 138 (52%) |
Coma | 67 (25%) |
Cardiac arrest | 19 (7%) |
Sepsis | 15 (6%) |
Other | 24 (9%) |
Unknown | 2 (1%) |
MV duration before inclusion—days | 4 ± 4 (4–5) |
Chest radiograph opacities—quadrants | 2 ± 1 (1–2) |
Parameters | CV period n = 265 | AV period n = 265 | p |
---|---|---|---|
DNP parameters | |||
DNPs duration—min | 12 ± 6 (11–13) | 12 ± 8 (11–13) | 0.95 |
Ramsay score | 4 ± 2 (4–4) | 4 ± 1 (4–4) | 0.35 |
Oxygenation before DNPs | |||
SpO2—%* | 96 ± 3 (95–96) | 95 ± 3 (95–95) | < 0.001 |
SpO2/FiO2* | 320 ± 79 (310–329) | 317 ± 87 (306–327) | 0.49 |
PaO2/FiO2** | 268 ± 95 (255–282) | 266 ± 92 (253–280) | 0.10 |
Hemodynamics during DNPs | |||
Heart rate—bpm † | 98 ± 19 (95–100) | 98 ± 20 (96–101) | 0.32 |
Mean arterial pressure—mmHg† | 89 ± 14 (87–90) | 88 ± 15 (86–90) | 0.56 |
Ventilation during DNPs | |||
Mode used in the CV period—n (%) | |||
Biphasic positive airway pressure | 230 (87%) | – | – |
Pressure support ventilation | 23 (9%) | – | – |
Volume controlled | 12 (4%) | – | – |
Tidal volume—mL/kg of PBW† | 10 ± 3 (10–10) | 10 ± 2 (10–10) | 0.40 |
Total RR—breath/min† | 28 ± 9 (27–29) | 27 ± 8 (26–28) | 0.79 |
Spontaneous RR—breath/min† | 14 ± 11 (13–15) | 22 ± 12 (21–24) | < 0.001 |
Passive ventilation—n (%)*** | 35 (13%) | 9 (3%) | < 0.001 |
Peak airway pressure—cmH2O† | 27 ± 6 (26–27) | 25 ± 7 (24–26) | < 0.001 |
Mean airway pressure—cmH2O† | 15 ± 4 (14–15) | 14 ± 4 (14–15) | < 0.001 |
PEEP—cmH2O† | 9 ± 3 (9–10) | 9 ± 3 (9–10) | 0.07 |
Endpoints
Outcome parameters | CV period n = 265 | AV period n = 265 | p |
---|---|---|---|
Primary outcome | |||
Time spent with SpO2 in the acceptable range—% of DNP duration* | 43 ± 37 (38–47) | 48 ± 37 (43–52) | 0.03 |
Secondary outcome | |||
Patients with SpO2 in the acceptable range during DNP—n (%)* | 123 (46%) | 160 (60%) | 0.001 |
Patients with at least one episode of: | |||
SpO2 ≤ 85%**—n (%) | 50 (19%) | 30 (11%) | 0.02 |
SpO2 < 90%**—n (%) | 92 (35%) | 69 (26%) | 0.03 |
Time spent with: | |||
SpO2 ≤ 85%—% of DNP duration | 3 ± 8 (2–4) | 2 ± 6 (1–2) | 0.03 |
SpO2 < 90%—% of DNP duration | 6 ± 11 (5–7) | 5 ± 12 (3–6) | 0.02 |
FiO2 100%—% of DNP duration | 6 ± 12 (4–7) | 4 ± 10 (3–6) | 0.09 |
SpO2 mean—% | 95 ± 3 (95–95) | 95 ± 3 (95–95) | 0.81 |
SpO2 min—% | 91 ± 6 (90–91) | 91 ± 8 (90–92) | 0.20 |
SpO2 max—% | 97 ± 2 (97–98) | 97 ± 2 (97–98) | 0.63 |