Inclusion criteria |
 1. Evidence of acute illness through: |
  a. acute admission to secondary care hospital, community hospital or NHS-funded intermediate care/rehabilitation facility |
  b. secondary care, community hospital or NHS-funded intermediate care/rehabilitation facility in-patient with onset of acute illness secondary to elective admission |
  c. recent secondary care hospital discharge to community hospital or NHS-funded intermediate care/rehabilitation facility |
 2. Aged ≥ 18 years |
 3. Have an expected total length of stay of 5 or more days |
 4. At high risk of PU development due to one or more of the following: |
  a. bedfast/chairfast AND completely immobile/very limited mobility (Braden activity score 1 or 2 and Mobility score 1 or 2) [20] |
  b. Category 1 PU on any pressure area skin site |
  c. localised skin pain on a healthy, altered or Category 1 pressure area skin site |
 5. Consent to participate (written informed consent, witnessed verbal consent, consultee agreement (England) or nearest relative/guardian/welfare attorney (Scotland)) |
 6. Expected to comply with the follow-up schedule |
 7. The patient is on an electric profiling bed frame |
Exclusion criteria |
 1. Have previously participated in the PRESSURE 2 trial |
 2. Have a current or previous Category ≥3 PU |
 3. Have planned admission to ICU where standard care is alternating-pressure mattress provision |
 4. Unable to receive the intervention (for example, sleep at night in a chair or unable to be transferred to randomised mattress) |
 5. Patient weight is lower or higher than weight limits for HSF and alternating-pressure mattresses (<45 kg/>180 kg) |
 6. It is ethically inappropriate to approach the patient |