Measurement of physiologic responses to mobilisation in critically ill adults

To identify physiologic variables that could be measured in response to mobilisation interventions in critically ill adults.

Physical activity may mitigate muscle damage from critical illness, but critically ill patients may have limited activity tolerance. Physiologic measures may be most useful in identifying safety and efficacy of mobilisation in this population.

A comprehensive literature search of electronic databases was conducted from 1990 to present, including CINAHL, MEDLINE the Cochrane Database of Systematic Reviews and PubMed. Search terms used were mobilisation, exercise, activity and critical illness. Seventeen articles were identified for review. Physiologic measurement approaches were reviewed for precision and accuracy.

Cardiopulmonary measures comprised the majority of physiologic variables identified, and multiple measures were used. Physiologic measures were primarily used as indicators of safety, although several efficacy measures were identified. Only one standardised tool was found that could be suitable as a safety measure, the Borg Rating of Perceived Exertion. The Medical Research Council Muscle Strength Grading Scale could be used as a physiologic outcome measure. Inflammatory biomarkers may be used as a novel measure of physiologic response. Descriptions of approaches to assure precision and accuracy of physiologic response measures were extremely limited.

Multiple physiologic variables should be measured when considering response to mobilisation in critically ill patients. Attention should be paid to procedures to assure accuracy and precision in measurement. Future studies including physiologic measures should include inflammatory biomarkers, and other measures of physiologic function, such as pain assessment.