Taylor 1999.

Study characteristics
Methods	Study objective: "... developing such a data hierarchy to support the adoption of a new PR support surface, the Pegasus Trinova, within an acute care setting" Study design: randomised controlled trial Study grouping: parallel group Duration of follow‐up: Trinova group mean 10.5 days (SD 1.2); control group 11.6 days (SD 1.4) Number of arms: 2 Single centre or multi‐site: single centre Study start date and end date: not described Setting: an acute care setting
Participants	Baseline characteristics Inclusion criteria: inpatients within a large NHS trust hospital; provided informed consent; free from pressure damage (including non‐blanching erythema); aged 16 or older; required nursing upon a pressure redistributing support surface Exclusion criteria: not described Sex (M:F): 12:10 in Trinova; 13:9 in alternating pressure air mattress Age (years): mean 66.50 (SD 2.20) in Trinova; mean 70.27 (SD 2.73) in alternating pressure air mattress Baseline skin status: median Waterlow 19 (range 10 to 30) in Trinova; 17 (10 to 35) in alternating pressure air mattress; free of existing ulcers Group difference: no difference Total number of participants: n = 44 Unit of analysis: individuals Unit of randomisation (per patient): individuals
Interventions	Intervention characteristics Pegasus Trinova Description of interventions: "an integrated dynamic mattress and chair cushion ... a mattress ... constructed in two layers, each with 19 cells ... A number of the air cells are designed to remain inflated during use ... Where cells are designed to provide dynamic support, these inflate and deflate in a three‐cell cycle over a 7.5 minute period ... alternating pressure air cushion, with four cells inflating and deflating over a 7.5 minute cycle" NPIAP S3I classification: powered, alternating pressure (active) air surface; hybrid system (active and reactive modes) Co‐interventions: not described Number of participants randomised: n = 22 Number of participants analysed: n = 22 Alternative dynamic mattress system Description of interventions: "The inflatable cells of the control mattress operated with alternate cells inflating, then deflating, over a 10‐minute cycle" NPIAP S3I classification: powered, alternating pressure (active) air surface Co‐interventions: not described. Number of participants randomised: n = 22 Number of participants analysed: n = 22
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): not described Definition (including ulcer stage): the number of individuals developing new ulcers Dropouts: not described Notes (e.g. other results reported): 0 of 22 in Trinova; 2 of 22 in alternating pressure air surface (1 non‐blanching erythema and 1 superficial skin breakdown) Time to pressure ulcer development Reporting: not reported Support‐surface‐associated patient comfort Outcome type: binary Reporting: partially reported Measurement method (e.g. scale, self‐reporting): Definition: patients rated their perceptions of both their comfort while resting upon the mattress and their overall opinion of the support surface ... elicited using Likert‐type scales Dropouts: not relevant Notes: only 1 arm has data. Eighteen of the 22 patients allocated to the Trinova completed the comfort questionnaire with the majority (n = 11; 61.1%) describing the mattress as being comfortable ... 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 Outcomes that are not considered in this review but reported in trials: Interface pressure
Notes
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Unclear risk	Quote: "randomised controlled trial (efficacy data)" Comment: unclear risk because no information about randomisation method provided.
Allocation concealment (selection bias)	Unclear risk	Quote: "Upon recruitment, the data collector opened the next opaque envelope in sequence to reveal to which mattress group the subject should be allocated" Comment: unclear risk of bias because it is unclear if envelopes were numbered and sealed.
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	Low risk	Outcome group: all outcomes (primary outcome) Comment: low risk of bias because no missing assumed.
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.