Related factors to semi-recumbent position compliance and pressure ulcers in patients with invasive mechanical ventilation: An observational study (CAPCRI study)

Background: Semi-recumbent position is recommended to prevent ventilator-associated pneumonia. Its implementation, however, is below optimal.

Objectives: We aimed to assess real semi-recumbent position compliance and the degree of head-of-bed elevation in Spanish intensive care units, along with factors determining compliance and head-of-bed elevation and their relationship with the development of pressure ulcers. Finally, we investigated the impact that might have the diagnosis of pressure ulcers in the attitude toward head-of-bed elevation.

Methods: We performed a prospective, multicenter, observational study in 6 intensive care units. Inclusion criteria were patients ≥18 years old and expected to remain under mechanical ventilator for ≥48h. Exclusion criteria were patients with contraindications for semi-recumbent position from admission, mechanical ventilation during the previous 7 days and prehospital intubation. Head-of-bed elevation was measured 3 times/day for a maximum of 28 days using the BOSCH GLM80(®) device. The variables collected related to patient admission, risk of pressure ulcers and the measurements themselves. Bivariate and multivariate analyses were carried out using multiple binary logistic regression and linear regression as appropriate. Statistical significance was set at p<0.05. All analyses were performed with IBM SPSS for Windows Version 20.0.

Results: 276 patients were included (6894 measurements). 45.9% of the measurements were <30.0°. The mean head-of-bed elevation was 30.1 (SD 6.7)° and mean patient compliance was 53.6 (SD 26.1)%. The main reasons for non-compliance according to the staff nurses were those related to the patient's care followed by clinical reasons. The factors independently related to semi-recumbent position compliance were intensive care unit, ventilation mode, nurse belonging to the research team, intracranial pressure catheter, beds with head-of-bed elevation device, type of pathology, lateral position, renal replacement therapy, nursing shift, open abdomen, abdominal vacuum therapy and agitation. Twenty-five patients (9.1%) developed a total of 34 pressure ulcers. The diagnosis of pressure ulcers did not affect the head-of-bed elevation. In the multivariate analysis, head-of-bed elevation was not identified as an independent risk factor for pressure ulcers.

Conclusions: Semi-recumbent position compliance is below optimal despite the fact that it seems achievable most of the time. Factors that affect semi-recumbent position include the particular intensive care unit, abdominal conditions, renal replacement therapy, agitation and bed type. Head-of-bed elevation was not related to the risk of pressure ulcers. Efforts should be made to clarify semi-recumbent position contraindications and further analysis of its safety profile should be carried out.