Table 4.
Summary of studiesa
| Baseline ventilation | Best PaO2/FiO2 ratio variation (mmHg), PP + RM | |||||||||
|---|---|---|---|---|---|---|---|---|---|---|
| Study | ARDS type, number of patients | Vt, mL | RR, breaths/minute | PEEP, cmH2O | PaO2/FiO2 ratio, mmHg | Pplat, cmH2O | Pre-PaO2/FiO2 ratio, mmHg | Post- PaO2/FiO2 ratio, mmHg | RM type | Study design |
| Pelosi et al., 2003 [43] |
Early ARDS (n = 10): 6 pulmonary, 4 extrapulmonary | About 7 mL/kg 590 mL |
14 | 14 | 121 | 32 | 193 | 240 | Sigh: Three consecutive volume-limited breaths/minute with a plateau pressure of 45 cmH2O | Following period of the study: 2-hour baseline SP 1-hour sigh SP 1-hour baseline SP 2-hour baseline PP 1-hour sigh PP 1-hour baseline PP Measurements taken at end of each period |
| Lim et al., 2003 [45] |
Early ARDS (n = 47): 37 pulmonary, 10 extrapulmonary 19 patients from a preliminary study |
About 8 mL/kg | 20 | 10 | 128 | - | 166 | 200 | Extended sigh Inflation phase: PEEP was increased by 5 cmH2O every 30 seconds with a 2 mL/kg decrease in Vt. When PEEP reached 25 cmH2O, CPAP at 30 cmH2O was used for 30 seconds. Deflation phase |
Following period of the study: Patients were randomised into two arms: (1) RM + PEEP at 15 cmH2O (n = 20) or (2) PEEP alone at 15 cmH2O (n = 8). A third arm of patients from a preliminary study were analysed: RM only (n = 19). PP was used only if PaO2/FiO2 ratio was < 100 (n = 14). The protocol started after 2-hour PP. Data were recorded before and after RM + PEEP (or PEEP only or RM only) at 15, 30, 45 and 60 minutes after the protocol. |
| Oczenski et al., 2005 [44] |
Early ARDS (n = 15): all extrapulmonary | About 6 mL/kg 460 to 490 mL |
18 | 15 | 130 | 29 | 176 | 322 | CPAP: 50 cmH2O for 30 seconds | Following period of the study: After 6-hour PP period, RM was performed. Data were recorded in SP after 6 hours PP and 3, 30 and 180 minutes after RM in SP. |
| Rival et al., 2011 (present study) |
Early ARDS (n = 16): 12 pulmonary, 4 extrapulmonary | - 540 mL |
19 | 10 | 98 | 25 | 177 | 218 | Extended sigh inflation phase: Pressure levels 30, 35, 40 and 45 cmH2O every 30 seconds were used. At 45 cmH2O, a 30-second end inspiratory pause was performed. Deflation phase |
Following period of the study: 6-hour SP with RM at beginning of SP. Six-hour PP with two RM after 1 hour and 6-hour PP. Measurements taken at beginning of, before and after each RM, and also at end of each ventilation period and 1 hour after end of protocol. |
aARDS: acute respiratory distress syndrome; Vt: tidal volume; RR: respiratory rate; PEEP: positive end expiratory pressure; PP: prone position; SP: supine position; RM recruitment manoeuvre; PaO2/FiO2 ratio, ratio of arterial oxygen partial pressure to fraction of inspired oxygen; Pplat: plateau pressure; CPAP, continuous positive airway pressure.