Simplified Acute Physiology Score 2 and Pressure Ulcer Prediction in ICU.

Overview

Critically ill patients admitted in intensive care units are at high risk of developing pressure ulcer (also known as pressure injury). In Bordeaux teaching hospital, a prevalence survey identified the department of anaesthesia and Intensive Care Unit with the highest rate for pressure ulcer (up to 29% of patients). Yet, developing a PU will increase patient's pain, health expenses, and the risks for further complications such as infection, prolonged hospitalization and a higher mortality rate. Therefore, this study aims at improving pressure ulcer prediction by using the Simplified Acute Physiology Score 2 (SAPS 2) as the latter estimates the severity of a patient condition while factoring in several causative factors for pressure ulcer among ICU patients. This could then lead to a better use and allocation of human and material resources and improve patients' care.

Pressure ulcers are soft tissue lesions induced when an unrelieved pressure, from a prominent bone, is applied on the skin and the underlying tissues, leading to ischemia and eventually necrosis of the area. Commonly, pressure ulcers are often located at the sacrum and heels. Yet, developing rapidly, they burden patients' illness and hospital care and costs: an increase in the length of stay of 11.2 days and additional costs of € 5,612 per patient in 2012. Although pressure ulcers are a common issue for hospitalized patients (12.5%) in France according to the SRLF, the prevalence rate is greatly higher in Intensive Care Units (30%) due to several factors inherent to the type of critically ill patients admitted: severity of the initial condition, age, weight, altered perfusion/oxygenation ratio, and length of stay. Currently, nurse staff at medical ICU Bordeaux teaching hospital are using the Braden scale as the gold standard to predict the risk for pressure ulcer formation. Despite its high sensitivity (more than 80% of critically ill adult patients are identified at high risk), this scale is well known to have a low specificity which makes its use suboptimal. This scale does not indeed process ICU-specific predictive factors for pressure ulcer risk. Some of these factors, as aforementioned, are integrated into the Simplified Acute Physiology Score 2, which assesses the severity of patients upon admission and is systematically and mandatorily collected by medical teams. Studies show that 35% of patients with a SAPS 2 ≥ 33 have pressure ulcers, compared to 17% of patients with a SAPS 2 ≤ 33, and that the risk of developing a pressure ulcer increases in conjunction with SAPS 2. Thus, the SAPS-2 could be useful for identifying patients at risk of developing pressure ulcers in ICU. Nurse staff at medical ICU Bordeaux teaching hospital therefore propose to evaluate the contribution of using the SAPS 2 (IGS-2) in addition to the Braden scale, to improve the prediction of the risk of sacral pressure ulcers, in adult patients hospitalized in medical intensive care, in order to better target patients to be treated and for a more effective and efficient use of human and material resources. We design a prospective observational cohort study, for a duration of 19 months, in which adult patients admitted in the Pellegrin medical intensive care unit will be considered for inclusion (first day) following inclusion and non-inclusion criteria. All included patients will be free of pressure ulcers upon admission. The scores studied in the project (Braden and SAPS 2/IGS-2) are measured beforehand and therefore without knowledge of the development of pressure ulcers. The prediction horizon used is 20 days, which corresponds to the maximum expected length of stay for the majority of patients in the target population.