Table 1 Study populations, interventions and definition of VAP

Drakulovic and colleagues [8]

Respiratory and medical ICU patients (90). Excluded: previous endotracheal intubation (<30 days); recent abdominal surgery; recent neurosurgical intervention; hemodynamic instability

T (39), 45°; C (47), 0°. Correctness of the position was checked once a day

Mean: T, 145 hours (SD 149); C, 171 hours (SD 167)

Clinically suspected VAP, defined as new and persistent infiltrate on chest radiography and at least two of the following three criteria: fever; leucopenia or leucocytosis; purulent tracheal secretions: T, 3/39; C, 16/47

Clinically suspected VAP: 34%

End of study protocol: (1) first weaning trial, (2) extubation, (3) death, (4) permanent change in body position for more than 45 minutes

Microbiologically confirmed VAP, defined as clinical suspicion and positive ETS, BAL or PSB: T, 2/39; C, 11/47

Microbiologically confirmed VAP: 23%

Follow-up for an additional 72 hours after the study end point has been reached

ICU mortality: T, 7/39; C, 13/47

For ICU mortality: 28%

Keeley [19]

Adult ventilated patients with no contraindications for raised head of bed (56). Excluded: previous endotracheal intubation (<30 days); recent abdominal surgery with vacuum dressing; severe obesitas; hemodynamic instability; renal replacement therapy; pregnancy; spinal surgery or trauma

T (17), 45°; C (13), 25°. Authors did not report whether correctness of the position was checked during the study

Mean^a: T, 3.8 days; C, 5.1 days

Clinically suspected VAP, defined as new and persistent infiltrate on chest radiography and at least two of the following three criteria: fever; leucopenia or leucocytosis; purulent tracheal secretions: T, 1/17; C, 2/13

Clinically suspected VAP: 15%

End of study protocol: (1) first successful weaning trial, (2) extubation, (3) death

Microbiologically confirmed VAP, defined as clinical suspicion and positive ETS, BAL or PSB: T, 4/17; C, 5/13

Microbiologically confirmed VAP: 38%

Follow-up for an additional 72 hours after the study end point has been reached

In-hospital mortality: T, 5/17; C, 4/13

In-hospital mortality: 31%

van Nieuwenhoven and colleagues [20]

Adult ventilated patients with no contraindications for raised head of bed and an expected duration of ventilation >48 hours (221). Excluded: selective decontamination of the digestive tract; trauma of the pelvic region; extensive abdominal surgery; neurosurgical patients treated with 30° head elevation; patients cared for in beds without the possibility of altering backrest elevation

T (112), 45°; C (109), 10°. Backrest elevation was measured every 60 seconds by means of a transducer with pendulum. A dedicated nurse controlled patient position two or three times daily and restored backrest elevation to the randomized position when possible

Median: T, 6 (0 to 281) days; C, 6 (0 to 64) days

Clinically suspected VAP, defined as new or persistent or progressive radiographic infiltrate with at least two of the following criteria: temperature >38°C or <35°C; leucopenia or leucocytosis; positive cultures of tracheal aspirate: T, 16/112; C, 20/109

Clinically suspected VAP: 18%

End of study protocol: (1) extubation, (2) death, (3) patients were placed in a bed without the possibility to alter backrest elevation, (4) VAP

Microbiologically confirmed pneumonia, defined as clinical suspicion and positive BAL or positive blood culture with the same microorganisms as in tracheal aspirate: T, 13/11; C, 8/109

Microbiologically confirmed VAP: 7%

Authors did not report whether there was a follow-up for an additional 72 hours after the study end point has been reached

ICU mortality: T, 33/112; C, 33/109

ICU mortality: 30%

Pressure sore^b: T, 31/112^c; C, 33/109^c

Feasibility of the allocated position^d