| Methods |
RCT with 6‐day follow‐up. |
| Participants |
Patients admitted for surgery lasting at least 2 h in lithotomy position, aged ≥18; admitted with intact skin. |
| Interventions |
1. Experimental mattress overlay in operating room made of foam with a 25% indentation load deflection (ILD) of 30 lb and density of 1.3 cubic feet (n = 206).
2. Usual care (padding as required, including gel pads, foam mattresses, ring cushions (donuts) etc) (n = 207). |
| Outcomes |
1. Experimental operating room mattress overlay: 27% (55/206); 6 people had ulcers of grade 2 or more.
2. Usual care: 16% (34/207); 3 people had ulcers of grade 2 or more. |
| Notes |
Experimental product caused postoperative skin changes. Authors contacted for more information relating to grade of ulcer by group. |
| Risk of bias |
| Bias |
Authors' judgement |
Support for judgement |
| Random sequence generation (selection bias) |
Low risk |
Random‐numbers tables used. |
| Allocation concealment (selection bias) |
High risk |
Patients randomly assigned for consideration in study from operating room schedule, then screened by nurses or primary investigator against inclusion/exclusion criteria before randomisation to experimental or control group. |
| Blinding (performance bias and detection bias)
Pressure ulcer incidence |
Low risk |
“Beginning on the day after surgery an continuing for 6 days, 2 research assistants, blinded to the study group of the patient, examined the skin over the bony prominences of each patient for any evidence of skin changes”. |
| Incomplete outcome data (attrition bias)
All outcomes |
Low risk |
No attrition. |
| Selective reporting (reporting bias) |
Low risk |
All pre‐specified outcomes reported. |
| Free of other bias ‐ were groups similar at baseline regarding the most important prognostic indicators? |
Low risk |
No important baseline differences. |
| Free of other bias ‐ was the timing of the outcome assessment similar in all groups? |
Low risk |
No other concerns. |
