Strength Testing After Nitrate Delivery (STAND) in ICU Patients

Overview

It is well documented that intensive care unit (ICU) patients have lower levels of skeletal muscle strength compared to non-ICU patients upon hospital discharge, and this weakness affects the patient's ability to perform basic activities of daily living upon hospital discharge and for extended periods thereafter. Recently, critically ill ICU patients have been shown to have lower nitric oxide levels. These patients often suffer from a disturbed homeostasis with circulatory and metabolic abnormalities that may potentially contribute to their ICU acquired weakness. Given the recent research showing dietary nitrate supplementation can increase nitric oxide levels and improve exercise tolerance in healthy and diseased older individuals, our aim is to investigate the importance of nitrate supplementation in ICU patients with focus on physical function and ICU acquired muscle weakness.

The proposed study is an investigator initiated, double blind, placebo controlled experimental study designed to evaluate the effect of chronic NO3- supplementation via beetroot juice ingestion on the skeletal muscle strength and physical function in ICU patients. Patients will be randomized to receive either nitrate rich or nitrate depleted beetroot juice once daily during their ICU and hospital stay. Physical function and skeletal muscle strength will be measured at ICU (± 2 days) and hospital (± 2 days) discharge and 2 months (± 2 weeks) after enrollment. Plasma levels of nitrate and nitrite will be measured 1, 3 and 5 days after randomization into the trial and at ICU and hospital discharge. Skeletal muscle ultrasound will be performed to examine the size and echogenicity of patient muscles. Self-reported physical function will be measured using the Functional Performance Inventory Short Form (FPI-SF). The FPI-SF provides an overall score of patient self-reported functional performance in the areas of household maintenance, movement, family and social activities, work, avocation and recreation