How Often Should Someone Be Turned to Prevent Pressure Injuries?

Quick answer: repositioning genuinely prevents pressure injuries, but the familiar "turn every two hours" rule is a convention rather than a proven optimum. Current thinking is to set the interval by the person's actual risk and their skin's response, not by the clock alone. A randomised trial at Assistance Publique, Hopitaux de Paris (NCT04550182) enrolled 1,232 intensive care patients to test a schedule where turning frequency was reset daily from the Braden risk score, against usual practice.

Why does repositioning work at all?

A pressure injury develops when soft tissue is squeezed between a bone and a surface for long enough that blood cannot get through. Skin over the sacrum, heels, hips, shoulder blades and the back of the head is most exposed because there is little padding there. Add friction and shear, the dragging force when someone slides down the bed, and damage can begin deep in the muscle before anything shows on the surface.

Moving the person changes which tissue is loaded and lets the previously compressed area reperfuse. That is the whole mechanism. Everything else, the mattress, the cushions, the dressings, is there to lengthen the time a position can safely be held or to protect skin that is already fragile.

Where did "every two hours" come from?

It is an old nursing convention that stuck because it is easy to remember and easy to roster. What it is not is a number derived from a trial showing that two hours beats three or four for everyone. People differ enormously: someone who is well nourished, well perfused and on a high specification foam mattress tolerates far more than someone in shock on vasopressors. A fixed interval will be too slow for one person and needless disturbance for another, and waking a frail person every two hours through the night carries its own costs in sleep, pain and agitation.

What was the Paris trial testing?

The trial (NCT04550182), sponsored by Assistance Publique, Hopitaux de Paris, randomised adult intensive care patients into two groups, with 1,232 people enrolled in total. It ran from April 2021 to July 2024 and is listed as completed.

In the experimental arm, the Braden scale was scored every morning and the turning frequency was set from that score: roughly two-hourly at the highest risk, four-hourly at moderate risk, and at lower risk no obligatory turn but a skin check and friction relief every six hours. The comparison arm simply received the unit's usual practice, with the frequency and method of turning recorded as it happened. The primary outcome was the proportion of patients with a pressure ulcer at day 28. Secondary outcomes included how tolerable and workable the schedule was in practice, length of intensive care stay, and how much staff time repositioning consumed.

Honest status: no results have been posted to the ClinicalTrials.gov record, so we cannot tell you whether the risk-adapted schedule prevented more injuries than usual care. What the design tells you is the direction the field is moving: away from one interval for everybody, towards a frequency matched to measured risk, and with an explicit interest in whether that is even deliverable on a busy ward.

What actually matters when you reposition someone at home?

• Lift and roll, do not drag. Sliding someone up the bed shears the skin over the sacrum. Use a slide sheet and two people where possible.
• Use the 30 degree tilt. Propping the person on a 30 degree side lean with pillows keeps weight off the hip bone itself. Lying fully on the side puts the whole load through one small bony point.
• Keep the head of the bed as low as is safe. Sitting up beyond about 30 degrees makes the body slide down, which is a shear problem as much as a pressure one. Feeding, reflux and breathing may require more elevation, so this is a balance, not a rule.
• Float the heels. Heels have almost no padding and are a common site. A pillow lengthways under the calves, keeping the knees slightly bent, lifts them clear of the bed entirely.
• Look at the skin at every turn. This is the real point of the schedule. Redness that does not fade when you press it lightly, or a patch that feels boggy, warmer or cooler than the skin around it, means that area needs to be kept unloaded from now on.
• Do not massage a red area. Rubbing damaged tissue makes it worse.
• Keep skin clean and dry. Skin that is wet with urine, sweat or wound fluid breaks down at far lower pressures. Manage incontinence promptly and use a barrier product on at-risk skin.
• Do not forget chairs. Sitting concentrates a great deal of pressure on a small area. Someone sitting out needs relief more often than someone lying down, not less.

Should the interval be shorter for some people?

Yes, in practice. Turn more often when the person cannot shift their own weight at all, is poorly nourished or dehydrated, has poor circulation or diabetes, has a fever, is on a basic hospital mattress rather than a pressure redistributing one, or already has redness that is slow to fade. The skin check is what tells you: if a mark is still visible when you come back, the previous interval was too long for that position.

When should you get help?

Ask a doctor or wound care nurse to review if you see redness that does not fade after the pressure is removed, a blister, a break in the skin, a purple or maroon patch, or skin that feels unusually firm or spongy. Get help the same day if a wound is developing an odour, spreading redness or warmth around it, discharge, or if the person becomes feverish or confused. Deep pressure damage often looks small on the surface while being far more extensive underneath, so an early look is worth much more than watchful waiting.

This article is general information, not medical advice. Please consult your doctor, wound care nurse or other qualified professional about your own situation.

EMIS+ supplies wound care, continence and pressure care products to homes, clinics and care facilities across Singapore. You can browse our range at www.emis.asia.

Related reading: Nutrition and Pressure Injuries: Why Feeding the Patient Is Part of the Dressing Plan, or browse pressure-relief and dressing options in our wound care range.