Price 1999.

Study characteristics
Methods	Study objective: to compare the effects on pressure damage prevalence by using 2 different support systems in patients with fractured neck of femur who were at high risk Study design: randomised controlled trial Study grouping: parallel group Duration of follow‐up: post‐operation 7 days; post‐operation 14 days Number of arms: 2 Single centre or multi‐site: single centre Study start date and end date: not described Setting: hospital ward
Participants	Baseline characteristics Inclusion criteria: patients with fractured neck of femur (confirmed by X‐ray), who were over 60 years old and identified as being ‘at very high risk’ of developing tissue damage (Medley score > 25) Exclusion criteria: not specified Sex (M:F): 11:29 in Repose; 5:35 in NIMBUS II Age (years): mean 83.5 (range 67.3 to 96.2) in Repose and 80.9 (64.4 to 98.4) in NIMBUS II Baseline skin status: at very high risk defined by Medley score > 25 Group difference: no difference Total number of participants: 80 Unit of analysis: individuals Unit of randomisation (per patient): individuals
Interventions	Intervention characteristics Repose Description of interventions: a low‐unit‐cost system (Repose) ... comprising a low‐pressure inflatable mattress and cushion that are readily portable and require little maintenance ... manufactured using a special polyurethane material that has a multidirectional stretch, is vapour permeable, waterproof and X‐ray translucent NPIAP S3I classification: non‐powered, reactive air surface Co‐interventions: standard best practice as appropriate to condition, including regular repositioning Number of participants randomised: n = 40 Number of participants analysed: n = 24 at 14‐day time point NIMBUS II plus Alpha TranCell Description of interventions: the system ... comprised a dynamic flotation mattress (Nimbus II) together with an alternating‐pressure cushion for a chair (Alpha TranCell) ... The alternating pressure cushion is designed for use on a chair or wheelchair. NPIAP S3I classification: powered, alternating pressure (active) air surface Co‐interventions: standard best practice as appropriate to condition, including regular repositioning Number of participants randomised: n = 40 Number of participants analysed: n = 26 at 14‐day time point
Outcomes	Proportion of participants developing a new pressure ulcer Outcome type: binary Time points: 7 days; 14 days Reporting: partially reported Measurement method (e.g. scale, self‐reporting): classified as 0 = normal skin; 1 = persistent erythema of the skin; 2 = blister formation; 3 = superficial sub/cutaneous necrosis; 4 = deep subcutaneous necrosis (not specified which classification system was used) Definition (including ulcer stage): no. of patients with a pressure ulcer at any stage [note: not all incident pressure ulcers] Dropouts: 16 in Repose and 14 in NIMBUS II plus Alpha TranCell Notes (e.g. other results reported): at 7 days: 6 of 32 in Repose (3 Grade 1; 2 Grade 2 and 1 Grade 3) and 5 of 31 in NIMBUS II (4 Grade 1; 1 Grade 2 and 0 Grade 3); at 14 days: 5 of 24 in Repose (2 Grade 1; 0 Grade 2 and 3 Grade 3) and 4 of 26 in NIMBUS II (2 Grade 1; 1 Grade 2 and 1 Grade 3). Data may not be useful because they are a mixture of new ulcers and pre‐existing ulcers, not just new ulcers. Time to pressure ulcer development Reporting: not reported Support‐surface‐associated patient comfort Outcome type: continuous Time points: 14 days Reporting: partially reported Measurement method (e.g. scale, self‐reporting): measured using a 100 mm visual analogue scale Definition: not specified what patient comfort is Dropouts: 16 in Repose and 14 in NIMBUS II plus Alpha TranCell Notes: mean 67 (SD 18) for 24 individuals in Repose; 60 (25) for 26 individuals in NIMBUS II 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: "a concealed computer generated list was used to randomise eligible consecutive consenting patients to one of the support systems" Comment: low risk of bias because of the use of a proper randomisation method.
Allocation concealment (selection bias)	Low risk	Quote: "a concealed computer generated list was used to randomise eligible consecutive consenting patients to one of the support systems" Comment: low risk of bias because of a proper concealment method.
Blinding of participants and personnel (performance bias) All outcomes	High risk	Outcome group: primary outcome Comment: high risk of bias because blinding was not possible for this comparison.
Blinding of outcome assessment (detection bias) All outcomes	High risk	Outcome group: primary outcome Quote: "Patients were not assessed blindly as it was considered that displacement for examination would cause excessive discomfort. A team of trained researchers completed all assessments" Comment: high risk of bias because no blinding was done.
Incomplete outcome data (attrition bias) All outcomes	High risk	Outcome group: primary outcome Quote: "No patient was excluded from all the analyses" Quote: "Data were not available for the 14‐day follow‐up assessment for a further 12 patients who were transferred to wards or hospitals that were not involved in the study or were discharged home" Comment: high risk of bias because 16 in Repose and 14 in NIMBUS II plus Alpha TranCell actually missed and were not included in analysis.
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.