Finnegan 2008.

Study characteristics
Methods	Study objective: to compare the effectiveness of a specialised alternating air pressure mattress replacement system and an air‐fluidised integrated bed in the management of post‐operative flap patients Study design: pilot randomised controlled trial Study grouping: parallel group Duration of follow‐up: mean length of stage 8.0 days (range 0 to 21) Number of arms: 2 Single centre or multi‐site: single centre Study start date and end date: not described Setting: tertiary referral centre
Participants	Baseline characteristics Inclusion criteria: 18 years or older who were admitted for reconstructive surgery to repair a tissue deficit (full‐thickness pressure ulcer involving muscle, fascia and, in some cases, bone) in the sacral‐coccygeal, trochanteric or ischial region. Exclusion criteria: unlikely or unwilling to comply with the treatment protocol, which included a minimum of 7 days bed rest within the surgical unit, or unable to consent. Sex (M:F): overall 21:12; 7:8 in alternating therapy; 14:4 in air‐fluidised bed Age (years): mean 56 (range 20 to 80); 62 in alternating therapy; 50 in air‐fluidised bed Baseline skin status: severe full‐thickness pressure ulcers Group difference: not described Total number of participants: 40 randomised, 33 analysed Unit of analysis: individuals Unit of randomisation (per patient): individuals
Interventions	Intervention characteristics Alternating therapy Description of interventions: a specialised alternating therapy support surface (Nimbus 3 Professional, Huntleigh Healthcare LLC). Specialised by means of Vent Valve Technology, not a standard alternating pressure therapy. Single cells to be isolated and permanently deflated beneath the operative site. This deflation completely off‐loads the most vulnerable tissue while the mattress continues to deliver optimised cyclic pressure redistribution to other vulnerable areas. NPUAP S3I classification: powered, alternating pressure (active) air surface Co‐interventions: all other care including repositioning, nutrition and continence management in line with the wound centre's protocol Number of participants randomised: n = 19 Number of participants analysed: n = 15 Air‐fluidised bed Description of interventions: air‐fluidised bed system (Clinitron, Hill‐Rom Inc.) (Finnegan 2008); "Clinitron® Air Fluidized Therapy beds ... minimizes interface pressure, while maximizing the surface’s immersion and envelopment properties to support healing ... providing statistically lower interface pressure ... Medical grade, silicone‐coated bead fluidization promotes a flotation environment" from Hillrom website (https://www.hill-rom.com/ca/Products/Products-by-Category/Hospital-Beds-and-Long-Term-Care-Beds/Clinitron-RiteHite-Air-Fluidized-Beds/). NPUAP S3I classification: non‐powered, reactive air‐fluidised surface Co‐interventions: all other care including repositioning, nutrition and continence management in line with the wound centre's protocol Number of participants randomised: n = 21 Number of participants analysed: n = 18
Outcomes	Proportion of participants developing a new pressure ulcer Outcome type: binary Time points: unspecified; hospital stay of 8 days Reporting: partially reported Measurement method (e.g. scale, self‐reporting): assessed by surgical team Definition (including ulcer stage): tissue integrity at other vulnerable anatomical locations Dropouts: 4 in alternating therapy; 3 in air‐fluidised bed (all due to not receiving the allocated intervention) Notes (e.g. other results reported): 0 of 15 in alternating therapy; 0 of 18 in air‐fluidised bed Time to pressure ulcer development Reporting: not reported Support‐surface‐associated patient comfort Outcome type: binary Time points: unspecified; hospital stay of 8 days Reporting: partially reported Measurement method (e.g. scale, self‐reporting): self‐reported Definition: subject acceptability ‐ numbers of patients having comfortable response on support surfaces Drop outs: 4 in alternating therapy; 3 in air‐fluidised bed (all due to not receiving the allocated intervention) Notes (e.g. other results reported): comfortable: 11 of 15 in alternating therapy; 4 of 18 in air‐fluidised bed; uncomfortable: 2 of 15 vs 7 of 18; the rest of the patients had no view. 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: cost of support surface provision based on rental costs per day of inpatient care (USD 35/day for alternating therapy; USD 65/day for air‐fluidised bed) Outcomes that are not considered in this review but reported in trials: Integrity of the surgical site.
Notes
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	Quote: "allocation was determined by using web‐based random‐number software" Comment: low risk of bias due to the use of a proper randomisation method.
Allocation concealment (selection bias)	Unclear risk	Quote: "Groups were concealed in sealed envelopes" Comment: unclear risk of bias because a proper concealment method is not specified.
Blinding of participants and personnel (performance bias) All outcomes	Unclear risk	Outcome group: all outcomes Comment: no information provided.
Blinding of outcome assessment (detection bias) All outcomes	High risk	Outcome group: primary outcome Quote: "Tissue integrity on discharge was not blinded and determined by the surgical team responsible for this pilot phase." Comment: high risk of bias because no blinding was undertaken. Outcome group: comfort outcome Comment: unclear risk of bias because it is not specified if patients who reported comfort data were blinded.
Incomplete outcome data (attrition bias) All outcomes	Unclear risk	Outcome group: all outcomes. Quote: "four subjects in Group A and three subjects in Group B did not receive the allocated intervention (Fig. 2) and were not included in the follow‐up" Comment: unclear risk of bias because a fair proportion of subjects lost to follow‐up.
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.