Theaker 2005.

Study characteristics
Methods	Study objective: evaluate the effectiveness of 2 devices, the Hill‐Rom Duo mattress and the KCI TheraPulse Study design: randomised controlled trial Study grouping: parallel group Duration of follow‐up: 20 (5‐127) days length of stay (2 weeks follow‐up after study) Number of arms: 2 Single centre or multi‐site: single centre Study start date and end date: not described Setting: an intensive care unit of a hospital
Participants	Baseline characteristics Inclusion criteria: patients admitted to the intensive care unit and classified as being at high‐risk. Exclusion criteria: patients aged < 18 years and those with a pressure sore upon admission; those transferred from other ward areas or hospitals and had been nursed on a pressure‐relieving device other than a Transfoam (Karomed – Division of Verna Ltd, Somerset, UK) or Therarest (KCI Medical Ltd) mattress within the last 7 days Sex (M:F): 20:10 in KCI TheraPulse; 19:13 in Hill‐Rom Duo Age (years): 65 (26‐85) across groups Baseline skin status: at risk; free of existing ulcers Group difference: no difference Total number of participants: n = 62 Unit of analysis: individuals Unit of randomisation (per patient): individuals
Interventions	Intervention characteristics KCI TheraPulse bed Description of interventions: KCI TheraPulse bed ... uses optional pulsation technology and low‐air‐loss to reduce tissue interface pressure ... consist of cells that are connected to a pump that inflate and deflate either at a 5‐10 min time cycle or continuously NPIAP S3I classification: powered, alternating pressure (active) air surface; hybrid (active and reactive modes) low‐air‐loss surface Co‐interventions: not described Number of participants randomised: n = 30 Number of participants analysed: n = 30 Hill‐Rom Duo mattress Description of interventions: Hill‐Rom Duo mattress ... uses either continuous or alternating low pressure modes ... consist of cells that are connected to a pump that inflate and deflate either at a 5‐10 min time cycle or continuously NPIAP S3I classification: powered, alternating pressure (active) air surface; hybrid mattress (active and reactive modes) Co‐interventions: not described Number of participants randomised: n = 32 Number of participants analysed: n = 32
Outcomes	Proportion of participants developing a new pressure ulcer Outcome type: binary Time points: not described Reporting: partially reported Measurement method (e.g. scale, self‐reporting): classified using the Lowthain scale Definition (including ulcer stage): not described Dropouts: not described Notes (e.g. other results reported): 3 of 30 in KCI TheraPulse; 6 of 32 in Hill‐Rom Duo Time to pressure ulcer development Reporting: not reported Support‐surface‐associated patient comfort Reporting: not reported All reported adverse events using allocated support surfaces Reporting: not reported Health‐related quality of life (HRQOL) Reporting: not reported Cost‐effectiveness Reporting: not reported
Notes
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	Quote: "... randomly assigned to either a Hill‐Rom Duo mattress or a KCI TheraPulse bed" Quote: "Selection of an unmarked envelope from a pile of envelopes by staff unconnected with the study formed the randomisation process" Comment: low risk of bias because a proper randomisation method applied.
Allocation concealment (selection bias)	Unclear risk	Comment: "Selection of an unmarked envelope from a pile of envelopes by staff unconnected with the study formed the randomisation process" Comment: low risk of bias because it is likely that allocation was properly concealed.
Blinding of participants and personnel (performance bias) All outcomes	High risk	Outcome group: all outcomes (primary outcome) Quote: "... unblinded randomised prospective trial" Comment: high risk of bias because it is clearly stated that this is an unblinded trial.
Blinding of outcome assessment (detection bias) All outcomes	Low risk	Outcome group: all outcomes (primary outcome) Quote: "If the nurse in charge of the patient’s care had a high level of suspicion that a pressure sore was present, the wound was digitally photographed. For study purposes, the digital photographs were anonymised and analysed subsequently by two independent Tissue Viability Nurses for confirmation of the existence of a pressure sore and assessment of severity" Comment: low risk of bias because efforts were made to minimise the risk of detection bias.
Incomplete outcome data (attrition bias) All outcomes	Low risk	Outcome group: all outcomes (primary outcome) Comment: no attrition.
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.