Comparison of Pressure Relief Properties of Operating Room Surfaces

Abstract

There are many operating room (OR) mattresspads and overlay surfaces; however, little empir-ical evidence is available regarding the pressure-reducing characteristics of these various surfaces.Foam and gel mattresses, with and withoutviscoelastic overlays, have been reported to reducethe skin interface pressure more effectively thanthe standard OR mattress pad [1–4]. Defloor andDeSchuijmer [5] reported that although the foammattress and the gel mattress had little pressure-reducing properties, the polyurethane and thepolyethermattresssignificantly(P!.001)reducedinterface pressures. However, none of the OR sur-faces studied (eg, polyurethane, polyether, gelmattress, foam mattress, standard OR mattress)reduced the pressures to less than 32 mm Hg. Itis relatively routine to use foam padding and geloverlays with the impression that padding the pa-tientrelievespressureandpreventspressureulcers.Therefore, this performance improvement studywas undertaken to describe the peak skin interfacepressuresinthespineandlateralpositionsonthreecommonly used OR surfaces.A key issue when positioning surgical patientsis the prevention of skin injury. Ischemic injuryand the potential development of pressure ulcersis a concern for any patient who remains in oneposition for prolonged periods. Although theincidence of pressure ulcers in acute care popula-tions is between 3% and 29%, the incidence forsurgical patients is higher, between 12% and 35%[6–8].This increased incidence is due in part to thecombined extended period of uninterrupted pres-sure and the forced immobility during surgicalprocedures in conjunction with the effects of anes-thesia [9].Prolonged exposure of the skin and underlyingtissues to high interface pressure or exposure tolow pressure over extended periods may predis-pose the patient to ischemic injury. Ischemicinjury occurs with increased frequency overweight-bearing bony prominences covered byskin and a small amount of muscle and sub-cutaneous tissue. In the supine position, morevulnerable sites include the occiput, scapula,olecranon process, sacrum, ischial tuberosities,and the calcaneous. In the lateral position, theear, acromion process, iliac crest, greater trochan-ter, lateral knee, and malleolus are the bonyprominences of concern. For the purpose of thisproject, the peak interface pressures over thebony prominences (occiput, sacrum, greater tro-chanter, and heels) were of interest.External pressure on tissues at capillary in-terface pressures greater than 32 mm Hg mayocclude capillary blood flow causing diminishedtissue perfusion and an ischemic injury that maylater manifest as a pressure ulcer [10]. The dura-tion of pressure is thought to be more of a contrib-uting factor than the intensity of the pressure,with 2 hours or longer associated with the devel-opment of ischemic injury. Individuals who are