Visualizing Tissue Strain Under the Sacrum and Coccyx in Different Supine Postures: A Case Series

Prediction of tissue deformation based on mechanical and physiological factors in the prone position during surgery

AIM

This study aimed to predict tissue deformation based on the pressure applied while lying in the prone position and physiological factors.

METHODS

Healthy volunteers were instructed to lie on mattresses of four different hardness levels (50, 87.5, 175, and 262.5 N). The order in which the mattresses were used was randomized per participant. Pressure at the iliac crests was measured using a pressure mapping sensor sheet. Participants were placed in the prone position for 10 min, with pressure data used from the latter 5 min. For the tissue deformation at the iliac crests, our previous study data were used. Multiple regression analysis was used to identify predictive mechanical and physiological factors.

RESULTS

The distance between the left and right greater trochanters, maximum interface pressure and age were significant predictors for compression of the skin and soft tissue. Significant predictors of internal soft tissue displacement were the distances between the left and right anterior superior iliac spines and greater trochanters. No factors predicted skin surface displacement.

CONCLUSIONS

Our study provided predictive factors that may be measured easily in a clinical setting to reduce the risk of pressure ulcers during surgery in the prone position.

The Role of Shear Stress and Shear Strain in Pressure Injury Development

ABSTRACT

Although other patient safety indicators have seen a decline, pressure injury (PI) incidence has continued to rise. In this article, the authors discuss the role of shear stress and shear strain in PI development and describe how accurate assessment and management can reduce PI risk. They provide explanations of shear stress, shear strain, friction, and tissue deformation to support a better clinical understanding of how damaging these forces are for soft tissue. Clinicians must carefully assess each patient's risk factors regarding shear forces within the contexts of activity and mobility. The authors also provide a toolbox of mitigation strategies, including support surface selection, selection of materials that contact the individual, management of immobility using positioning techniques, and the use of safe patient handling techniques. With a clear understanding of how shear forces affect PI risk and mitigation strategies, clinicians will more accurately assess PI risk and improve PI prevention care plans, ultimately reducing PI incidence to become more aligned with other patient safety indicators.

The theory and practice of pressure ulcer/injury risk assessment: a critical discussion

Pressure ulcer/injury (PU) risk assessment is widely considered an essential component in clinical practice. It is a complex and broad concept that includes different approaches, such as clinical judgement, using standardised risk assessment instruments, skin assessments, or using devices to measure skin or tissue properties. A distinction between PU risk assessment and early detection is important. PU risk measures the individual's susceptibility to developing a PU under a specific exposure (primary prevention), and early detection includes the assessment of early (sub)clinical signs and symptoms to prevent progression and to support healing (secondary prevention). PU risk is measured using prognostic/risk factors or prognostic models. Every risk estimate is a probability statement containing varying degrees of uncertainty. It therefore follows that every clinical decision based on risk estimates also contains uncertainty. PU risk assessment and prevention is a complex intervention, where delivery contains several interacting components. There is a huge body of evidence indicating that risk assessment and its outcomes, the selection of preventive interventions and PU incidence are not well connected. Methods for prognostic model development and testing in PU risk research must be improved and follow state-of-the-art methodological standards. Despite these challenges, we do have substantial knowledge about PU risk factors that helps us to make better clinical decisions. An important next step in the development of PU risk prediction might be the combination of clinical and other predictors for more individualised care. Any prognostic test or procedure must lead to better prevention at an acceptable cost.

Does Sacrococcygeal Skeletal Morphology and Morphometry Influence Pressure Injury Formation in Adults?

GENERAL PURPOSE

To present a study that investigated sacrococcygeal skeletal structure as a possible nonmodifiable intrinsic risk factor for pressure injury and identify possible issues caused by its morphology.

TARGET AUDIENCE

This continuing education activity is intended for physicians, physician assistants, nurse practitioners, and nurses with an interest in skin and wound care.

LEARNING OBJECTIVES/OUTCOMES

After participating in this educational activity, the participant will:1. Recognize the background information the authors considered when planning and conducting their study of sacrococcygeal skeletal structure as a possible pressure injury risk factor.2. Identify the characteristics of the two groups of study participants.3. Choose the results of the study clinicians may consider when implementing evidence-based practice.

Incidence and Variables Predictive of Pressure Injuries in Patients Undergoing Ventricular Assist Device and Total Artificial Heart Surgeries: An 8-Year Retrospective Cohort Study

OBJECTIVE

To investigate the incidence and risk factors of pressure injury (PI) development after ventricular assist device (VAD) or total artificial heart (TAH) surgery.

METHODS

The investigator reviewed all VAD-TAH surgeries performed between 2010 and 2018 in a large academic health system. The PIs were reported by case incidence, patient incidence, and incidence density for each of the respective 1,000 patient days during the study period. Statistics on four different VAD-TAH devices were assessed; variables significant in bivariate analysis were entered into a stepwise logistic regression model to identify significant predictors of PI.

RESULTS

The sample included 292 independent VAD-TAH surgeries among 265 patients. Thirty-two patients developed 45 PIs. The PI incidence was 11% (32/292), with a PI incidence per patient of 12% (32/265). Incidence density was 10 per 1,000 patient days (1%) for 2010-2012, 12 per 1,000 patient days (1.2%) for 2013-2015, and 10 per 920 patient days (1.1%) for 2016-2018. Logistic regression revealed that significant predictor variables for PI were age, mechanical ventilation time, and preoperative Braden Scale score. The mean time to PI was 23 days after admission and over 14 days after surgery, indicating a low rate of intraoperative and ICU-associated PI.

CONCLUSIONS

The incidence of PI was lower than anticipated given historic rates. Potential mechanisms by which these patients were protected from PI are discussed. Prospective studies to further investigate significant risk factors and effective prevention measures are warranted.