Rosenthal 2003.

Study characteristics
Methods	Study objective: to compare the rate of healing when patients were treated with low ‐air‐loss bed, pressure‐relieving bed overlays, and generic total contact seat surface Study design: randomised controlled trial Study grouping: parallel group Duration of follow‐up: 6 months Number of arms: 2 (of 3 arms) considered eligible for inclusion Single centre or multi‐site: multiple site Study start date and end date: not described Setting: long‐term care facilities, and community nursing homes
Participants	Baseline characteristics Inclusion criteria: those being alert, able to sit in the 6 months before the study, still sit up with assistance, with a stage III or IV ulcer on the coccyx, trochanter or ischial tuberosities Exclusion criteria: those with sacral pressure ulcers; previously in a trial to treat their current pressure ulcer; already on low‐air‐loss, or transfer to low‐air‐loss planned; skin grafting planned within 1 week; with an active sinus tract or fistula; poor nutrition; requiring antibiotics to treat methicillin‐resistant Staphylococcus aureus, vancomycin‐resistant Enterococci, or active skin infection; osteomyelitis diagnosed; body weight below 60 kg; unable to flex both hip and knee at least 90 degrees Sex (M:F): not given Age (years): mean 69.0 (SD 4.1) in low‐air‐loss (LAL) bed and 68.6 (3.0) in overlay Baseline skin status: all with grade III or IV ulcer Group difference: no difference Total number of participants: n = 76 Unit of analysis: individuals Unit of randomisation (per patient): individuals
Interventions	Intervention characteristics Low ‐air‐loss bed Description of interventions: low‐air‐loss suspension bed (TheraPulse bed) attaching a rack of inflatable fabric pillows to a modified bed frame to provide pulsating air support that was intended to increase capillary blood flow and to lower interface pressure. These beds are covered with the manufacturer's Gore‐Tex fabric surface to reduce friction. NPIAP S3I classification: powered, alternating pressure (active), low air loss air surface Co‐interventions: turning every 2 hours Number of participants randomised: n = 38 Number of participants analysed: unspecified Bed overlay Description of interventions: a pressure‐reducing advanced medium density open‐cell polyurethane foam overlay that was contour cut from 8.89 cm (3.5 inches) of solid foam. Each Geo‐Matt cell was meant to respond individually to the weight put on it, thereby customising support to minimise pressure and shear. Additional source of information is from http://www.spanamerica.com/ultramax.php. NPIAP S3I classification: non‐powered, reactive foam surface Co‐interventions: turning every 2 hours Number of participants randomised: n = 38 Number of participants analysed: unspecified
Outcomes	Proportion of participants developing a new pressure ulcer Outcome type: binary Time points: 6 months Reporting: partially reported Measurement method (e.g. scale, self‐reporting): not given Definition (including ulcer stage): not given Dropouts: 1 death excluded; 3 participants withdrawn at 4 weeks due to worsened condition, all in overlay group Notes (e.g. other results reported): no new pressure ulcers were found in either arm Time to pressure ulcer development Not reported Support‐surface‐associated patient comfort Not reported All reported adverse events using allocated support surfaces Notes: 1 death in this study but the authors did not specify which group the death was in; 3 participants withdrawn at 4 weeks due to worsened condition, all in overlay group Health‐related quality of life (HRQOL) Not reported Cost‐effectiveness Not reported Outcomes that are not considered in this review but reported in trials: Ulcer healing Time to ulcer healing
Notes
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	Quote: "Randomization was performed by placing a number corresponding to each experimental condition into a sealed envelope with an equal number of envelopes per condition. A research assistant with no clinical experience drew envelopes by lot as eligible subjects were identified" Comment: low risk of bias because the sequence generation process seems proper.
Allocation concealment (selection bias)	Unclear risk	Comment: no information provided.
Blinding of participants and personnel (performance bias) All outcomes	Unclear risk	Comment: no information provided.
Blinding of outcome assessment (detection bias) All outcomes	Unclear risk	Comment: no information provided.
Incomplete outcome data (attrition bias) All outcomes	Unclear risk	Comment: unclear risk of bias because the dropout rates are low but are unbalanced (1 death is excluded from analysis and it is unclear which group the death is in; 3 participants withdrawn at 4 weeks due to worsened condition, all in overlay group).
Selective reporting (reporting bias)	Low risk	Comment: the study protocol is not available but it is clear that the published reports include all expected outcomes, including those that were pre‐specified.
Other bias	Low risk	Comment: the study appears to be free of other sources of bias.