6.2 Repositioning, Shear Reduction, and Seating
Key Takeaways
- Every-2-hour turning is a starting convention; frequency is individualized to tissue tolerance, existing injuries, and the surface in use.
- A 30-degree lateral tilt unloads the sacrum without concentrating load on the greater trochanter, unlike 90-degree side-lying.
- Keep the head of bed as low as medically allowed, often 30 degrees or less, to reduce sacral shear, with exceptions for ventilation and aspiration.
- Boost with a lift or slide sheet; never drag. Seating needs a real cushion, supported feet, and a distinction between ischial loading and sacral sitting.
- Prone ICU positioning creates a new high-risk map: face, ears, breasts, genitalia, knees, and toes.
6.2 Repositioning, Shear Reduction, and Seating
Quick Answer: Turn frequency is individualized; every 2 hours is a starting convention, not a magic interval. Use a 30-degree lateral tilt rather than 90-degree side-lying to spare the trochanter. Keep the head of bed as low as medically allowed, often ≤30 degrees, to cut sacral shear—raising it for ventilation or aspiration risk. Lift or slide; do not drag. Seating needs a real cushion, supported feet, and a distinction between ischial and sacral sitting. In prone ICU positioning, protect face, ears, breasts, genitalia, knees, and toes.
Pressure is force over area. Shear is the parallel force that distorts tissue as bone slides while skin sticks to the sheet. Many sacral injuries are shear-plus-pressure injuries from a high head of bed plus a slide down in bed. Repositioning is therefore not left-back-right theater—it is a plan to change the loaded anatomy, reduce shear, and protect the next surface (chair as well as bed). OpenExamPrep covers these mechanics for CWCN study as independent clinical teaching, not as a WOCNCB-owned turning protocol.
Individualized turning, not a sacred every-2-hours rule
Turn every 2 hours is a starting convention rooted in historical nursing practice and still written into many care plans and into CMS conservative-treatment language for some support-surface coverage. It is not a physiologic constant. A well-perfused, independently fidgeting person on an appropriate reactive surface may tolerate longer intervals. A hypotensive, febrile, incontinent person with a Braden mobility of 1 may need more frequent offloading, small shifts, and heel floats even if the clock says 90 minutes have not elapsed.
Individualize using tissue tolerance (perfusion, fever, vasopressors, tobacco, diabetes), current injuries (do not park a person on an existing ulcer), the surface in use (a specialty mattress still needs turning), ability to make micro-movements, and an honest staffing plan. If you cannot turn, escalate the surface and the plan rather than charting a fictional interval. Small shifts (weight jiggle, pillow adjustments) help but do not replace a true offload of the at-risk prominence.
30-degree lateral tilt versus 90-degree side-lying
Full 90-degree side-lying dumps body weight onto the greater trochanter, a classic site for full-thickness injury. The preferred bed position for many at-risk adults is a 30-degree lateral tilt: the person is rolled just enough that the sacrum is unloaded and the trochanter is not the new pressure point. Pillows or wedges maintain the tilt. Check that the lower trochanter and lateral foot are not now loaded against the rail or a hard mattress edge.
Avoid stacking the upper leg so it adducts and loads the medial knee or the lower limb's peroneal nerve. Keep heels floated in every position. The goal is a new contact map, not a dramatic roll that looks complete in a photo and injures the hip.
Head of bed, sacral shear, and medical exceptions
Elevating the head of bed (HOB) increases sacral shear and pressure as the person slides toward the foot of the bed. Keep HOB as low as medically allowed, often ≤30 degrees, for people at sacral risk.
Exceptions are real and must be named:
- Ventilation and oxygenation (some ARDS or obesity strategies need a higher HOB)
- Aspiration risk and tube-feeding protocols (often 30–45 degrees during and after feeds)
- Heart failure orthopnea
- Procedure positioning
When HOB must be higher, intensify anti-shear tactics: a slight knee gatch or footboard to reduce slide, frequent small repositioning, sacral checks, and a surface with better envelopment. Do not pretend 45 degrees for aspiration has no pressure cost. Knees slightly flexed can reduce shear compared with a flat-leg slide.
| Position or maneuver | Intended effect | Main risk if done poorly |
|---|---|---|
| 30-degree lateral tilt | Unload sacrum without loading trochanter | Too little tilt leaves sacrum loaded; too much becomes 90-degree side-lying |
| 90-degree side-lying | Sometimes needed for hygiene or a procedure | Greater trochanter becomes the pressure point |
| HOB ≤30 degrees when allowed | Cut sacral shear | Compromised ventilation or aspiration protection if used blindly |
| Lift or slide sheet boost | Move the body without dragging skin | One-person yank still shears tissue |
| Sacral doughnut cushion | None that OpenExamPrep recommends | Ring-loads peri-wound tissue and can impair perfusion |
A nurse wants to unload a patient's sacrum in bed without creating a new full-thickness risk at the hip. Which position best matches that goal?
Sacral offloading and do not drag
Sacral offloading means the sacrum/coccyx is not the primary contact point: 30-degree tilt, prone if indicated and safe, or sitting with a posterior pelvic tilt avoided. A doughnut cushion is a trap—it can ring-load tissue and impair perfusion.
Never drag. Dragging creates friction at the skin and shear in deeper tissue. Use a lift or slide sheet / air-assisted lateral transfer device. Two-person boosts with a sheet still shear if the sheet does not actually slide. Overhead lifts for dependent people protect both tissue and staff. Grabbing a gait belt and yanking the person up the bed is a friction injury dressed up as a boost.
Seating: the other 12 hours
Many injuries start in the chair, not the bed.
- Wheelchair push-ups (if the person has triceps and is taught to clear the ischia) are active offloading; they are useless if the person cannot lift or forgets.
- Tilt-in-space chairs unload ischia by shifting weight to the back and posterior thighs without the shear of a simple recline (recline can slide the person forward).
- Cushion selection: air (adjustable immersion; needs a reliable inflation check), foam (stable, low maintenance, can bottom out), gel (envelopment and some shear reduction; heavy, can migrate). Hybrid cushions exist. Match to skin risk, postural need, and caregiver skill—not catalog price.
- Ischial versus sacral sitting: upright sitting loads ischial tuberosities. A posterior pelvic tilt or a slump (sacral sitting) loads the sacrum/coccyx—the same tissue you just protected in bed. Correct the posture and the cushion rather than adding a sacral dressing and calling it prevention.
- Feet supported on the floor or footrests so weight is not hanging from the ischia and the person is not sliding. Unsupported feet equal pelvic slide equal sacral load.
Limit continuous sitting time for high-risk skin; return to bed for full offload. Inspect ischia when the person comes out of the chair. A folded bath blanket is not a cushion.
Prone positioning in the ICU
Prone ventilation can save lungs and creates a new pressure map. Protect:
- Face (cheeks, forehead, lips) with a dedicated prone pillow or foam; watch the endotracheal tube and eyes
- Ears
- Breasts
- Genitalia (penis, scrotum, labia)
- Knees
- Toes (they plantarflex into the mattress)
Also watch iliac crests, anterior shoulders, and dorsa of feet. Reposition the head on a schedule. Do not let device tubing lie under a bony point. Prone is not pressure-free; it is a different set of high-risk sites.
Scenario: Mr. K slides to the foot of the bed
Mr. K is on bilevel positive airway pressure with the head of bed at 45 degrees. Every hour he is found at the footboard with a reddened sacrum. Staff boost him by grabbing a gait belt and yanking. He sits in a wheelchair with a folded blanket as a cushion and feet dangling.
Fix the physics: keep the head of bed at the lowest safe angle for the ventilation and aspiration plan; use a slide sheet or lift to boost; consider a slight knee gatch; inspect the sacrum now; replace the blanket with a pressure-redistributing cushion; support his feet; use a 30-degree tilt when recumbent, not 90-degree side-lying. A thicker brief does not fix shear. If he must stay at 45 degrees for the airway, that exception is named in the plan and offset with more frequent offloading—not ignored.
When reducing sacral shear, how should the head of bed be managed for an at-risk adult?
A dependent patient has slid toward the foot of the bed. Which method best protects skin while restoring position?
During prone ventilation, which set of sites needs planned protection because they become the new pressure map?