Study was withdrawn due to technical limitations to the device

Hospital-acquired pressure ulcers (HAPUs) are a well-established serious complication of hospitalization that have serious consequences on patient morbidity and mortality as well as the cost of care. At the core of the problem for patient-centered targeted prevention of HAPUs is the lack of knowledge surrounding the magnitude and duration of pressure necessary to cause pressure ulcers, and the lack of immediate feedback on whether these interventions do anything to substantially offload at risk areas. Previous studies have been inconsistent in their findings of an association between duration of time and HAPU occurrence. While retrospectively this has been investigated, there is currently no substantial prospective, randomized study.

This study seeks to better understand the interface pressures between the patient and his or her support surface and how this relates to the development of pressure ulcers. The effect of patient characteristics and the relationship between total length of time on the operating table and pressure ulcer development will also be assessed.

The findings from this study will significantly add to strengthening the body of evidence regarding pressure ulcer development, specifically the relationship between the magnitude of interface pressure between the patient and the support surface for what duration of time leads to the development of a pressure ulcer. The results will provide critical insight into the physiologic targets healthcare providers should use to develop better pressure ulcer prevention programs, which could ultimately lead to a reduction in the incidence of pressure ulcers.

Hospital-acquired pressure ulcers (HAPUs) are a well-established serious complication of hospitalization that have serious consequences on patient morbidity and mortality as well as the cost of care. Following CMS's changes to hospital reimbursements and penalization for hospitals with the highest rate of hospital-acquired complications, numerous quality improvement initiatives have been implemented. An overall reduction in the reported incidence of HAPUs from approximately 7 to 4.5% was observed, largely attributed to these interventions. Though there had been a drop in incidence, the overall number of hospitalized patients who develop HAPUs remains large and more recently HAPU frequency in hospitals has not continued to decrease, despite educational pressure ulcer prevention programs and clinical practice guidelines.

Due to the complications and costs associated with the development of a pressure ulcer, research has suggested that prevention is more effective than standard care. There are many current solutions for preventative interventions for HAPUs including leadership initiatives, data tracking, risk scales and many adjuvant pressure-offloading devices such as beds and mattress pads. Many of these devices have limited data supporting their effectiveness or are costly to implement in a purely prophylactic manner when current risk stratification methods fail to capture 60% of patients who go on to develop an ulcer. The vast majority of current preventative measures for pressure ulcers either seek to reduce the time a patient spends in one position or to reduce the magnitude of pressure that occurs on the high-risk areas for pressure ulcers. As such, manual repositioning (turning) is the most frequently used intervention as it is felt to be low-cost and part of standard care. Repositioning works by reducing or eliminating the interface pressure between the patient and the contact surface, but the standard recommendation on the 2 hour frequency were derived from animal studies and healthy volunteers. An expert consensus by Black et al. (2011) recommended the need for clinical decision-making based on the individual's needs and clinical situation when establishing a turning schedule, but there are very few objective tools that clinicians can use to make the decision.

At the core of the problem for patient-centered targeted prevention of HAPUs is the lack of knowledge surrounding the magnitude and duration of pressure necessary to cause pressure ulcers, and the lack of immediate feedback on whether these interventions do anything to substantially offload at risk areas. Previous studies have been inconsistent in their findings of an association between duration of surgery and HAPU occurrence, with results ranging from a negative association to a positive association.

This study seeks to better understand the interface pressures between the patient and his or her support surface and how this relates to the development of pressure ulcers. This data will provide critical insight into the physiologic targets healthcare providers should use to develop better pressure ulcer prevention programs and ultimately lead to a reduction in the incidence of pressure ulcers.

The primary outcome will be the interface pressure trend on the sacrum throughout the duration of time a patient is on the operating table and how that is correlated with pressure ulcer development. The effect of Braden scale score and other patient characteristics and the relationship between total length of time on the operating table and pressure ulcer development, and healthcare provider intervention in response to the pressure reading if in the second part of the study healthcare providers are not blinded to the pressure data.

This study will measure the interface pressure between a patient and his or her support surface in the operating room for prolonged (>2 hour) operative cases. Eligible patients will receive an adhesive padded bandage (similar to Mepilex Gentle Border) that collects interface pressure data. When the patient is being positioned in the operating room, this bandage will be applied to the sacrum. At the completion of the case the bandage will be removed and the status of the skin will be recorded and a photo of the sacrum will be taken for documentation. Skin status will be reassessed at 24 hours and at 1 week at regularly scheduled follow-ups with the surgeon. Pressure ulcer development will then be correlated with interface pressure characteristics during the operative case, using demographic data to check homogeneity between the experimental and control groups. If at interim analysis there is a clear relationship between a pressure threshold and pressure ulcer development, the second portion of the study will not blind healthcare providers to the live data. They would be able to see the pressure measurement and reposition the patient to effectively offload.

While retrospectively this has been investigated, there is currently no substantial prospective, randomized study. This study will significantly add to strengthening the body of evidence regarding pressure ulcer development, specifically the relationship between the magnitude of interface pressure between the patient and the support surface for what duration of time leads to the development of a pressure ulcer.

Inclusion Criteria:

• Patients undergoing an operation that is scheduled to last more than 2 hours

Exclusion Criteria:

• Existing sacral pressure ulcer, undergoing a cardiac procedure, or inability to provide informed consent.

The investigator and outcomes assessors will be masked to the pressure data during the operating room and follow-up.