Heels are the second most common anatomic site for pressure injuries1,2 and are particularly vulnerable because the skin that covers the posterior calcaneus (heel) bone is only about 3.8 mm thick, with the epidermis accounting for 0.46 mm.3 The usually angular shape of the calcaneus impacts tissue strain, so the part of the heel that rests on the bed or foot device experiences high pressure over a small area.1 The subcutaneous tissue is thin, highly vascularized, firm, and fibrous; it lacks muscle/fat tissue for cushioning/protection rendering it vulnerable to pressure and shear forces.4 Heel blood supply is equally compromised because it relies largely on collateral circulation from the posterior tibial artery.3,5,6 Diseases, conditions, medications, or prolonged heel positioning without relief can cause ischemic changes to the heel's skin surface.1,4
Risk Factors
A retrospective case-control study (n = 337)4 found four factors significantly and independently associated with a heel pressure injury (HPI): diabetes mellitus, vascular disease, immobility, and Braden Scale score <=18 on admission. When repeated in a larger, more diverse population (n = 1,697), seven variables were significantly and independently associated with an HPI: diabetes mellitus, vascular disease, perfusion issues, impaired nutrition, age >=65 years, mechanical ventilation, and surgery.7 The second study yielded a mnemonic-based enabler to assist clinicians in translating this evidence into practice (Figure 1).7
Some handy tips for practitioners from the 2019 International Guideline on the prevention and treatment of pressure injuries1 and other literature8,9 include:
Assess
Providers should evaluate heel vascular/perfusion status (including foot pulses, ankle brachial index, smoking status, edema), check patient heel sensation (eg, assess for peripheral neuropathy using monofilament testing assessment), and assess risk for HPI (physical assessment of heel skin condition,1 previous HPI, and if available newer devices to identify nonvisual signs of tissue deformation/edema as well as clinical condition, medical history, comorbidities, etc).1 The need for consults from other members of the interprofessional team should be determined.8,9
Prevent
The position of the heel is critical. Providers should be careful when transferring, turning, and repositioning patients to avoid damage to the heels and avoid both dorsiflexion and plantar flexion.8 Further, there should be no external or internal rotation of the foot because it increases tissue deformation (Figure 2).10 Heel suspension devices maintain feet in a neutral (90[degrees]) position (Figure 3) but proper leg and foot alignment (slight knee flexion, even pressure distribution under the calves, and proper foot alignment) must be ensured.1 The heel suspension device must be removed periodically (at least twice a day).1 Pillows are also sometimes used to offload or "float" the heels8 and should be placed vertically, creating even pressure distribution under the calf muscle as well as avoiding pressure to the vulnerable popliteal space and Achilles tendon (Figure 3).1 Providers may want to consider the use of a prophylactic dressing as an adjunct to offloading.1,11,12 The patient's clinical condition, tolerance for these interventions, and manufacturer guidelines should be considered when evaluating offloading methods. The National Pressure Injury Advisory Panel offers a free tip sheet on proper heel offloading.13
Treat
The principles of treating HPIs include pressure redistribution via care measures/offloading devices, skin protection, and local wound care based on the Wound Bed Preparation paradigm.1,9,12-14 Stable heel eschar should not be debrided in the presence of untreated peripheral vascular disease unless there is a high suspicion of infection.1
REFERENCES