In which of the following positions is the patient at greatest risk of shearing force?

AIIMS Patna NO - 2020

Nursing Foundation

Hard

Appeared in: AIIMS Patna NO - 2020

Explanation

High-Fowler's position involves elevating the head of the bed to 60-90 degrees.
This steep angle creates a strong downward gravitational force, causing the patient's skeleton and deep tissues to slide toward the foot of the bed.
Shearing occurs when the skin remains stationary against the bed linens while the underlying structures move, stretching and tearing blood vessels and tissue.
This position places the most pressure and shear force on the sacrum and heels, making it the highest risk for pressure injury development.

Option A: Semi-Fowler's position (head of bed at 30-45 degrees) poses a moderate, but not the greatest, risk. The angle is less steep, resulting in less gravitational pull and shearing force compared to High-Fowler's.
Option B: Lying supine (flat on the back) creates minimal risk for shearing force because there is no significant angle causing the body to slide downwards.
Option C: In the Trendelenburg position, the head is lower than the feet. This causes the body to slide toward the head of the bed, not the foot. Therefore, it does not create the typical shearing force on the sacrum and coccyx.

Clinical Relevance

Nursing practice connection: Use the key finding related to Risk factors for shearing force and patient positioning to guide bedside assessment, documentation, and the next nursing action.
Nurses must be vigilant in assessing and minimizing shear, as it is a primary contributor to the development of deep tissue pressure injuries, which are painful and difficult to treat.
A key nursing intervention is to limit the time a patient spends with the head of the bed elevated above 30 degrees, unless medically contraindicated (e.g., for respiratory distress or tube feeding).
What if? If a patient has severe respiratory distress and requires the High-Fowler's position, the nurse's priority becomes more frequent repositioning, using pressure-redistributing surfaces, and ensuring heels are elevated off the bed to mitigate the high risk of shear and pressure injuries.

How to Approach the Question

First, understand the definition of 'shearing force' in a clinical context: it's the friction and sliding between tissue layers, not just direct pressure.
Next, visualize how gravity would affect a patient's body in each of the listed positions.
Consider the angle of the bed for each position. A steeper angle will increase the tendency for the body to slide downwards.
Evaluate which position creates the most significant downward slide, where the skin might stick to the sheets while the skeleton moves. This identifies the position with the highest shear.
Compare High-Fowler's (60-90 degrees) to Semi-Fowler's (30-45 degrees). The higher angle directly translates to a greater risk.
Eliminate supine (flat) and Trendelenburg (head down) as they do not cause the downward sliding that leads to sacral shear.

Concept Tested & Keywords

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E6 Nursing Fundamentals Potter Perry 12e Part 4 pp. 155-157, 202-204

E6 Nursing Fundamentals Taylor p. 330-332