A randomized pilot study of nitrate supplementation with beetroot juice in acute respiratory failure.

Nitrate rich beetroot juice (BRJ) can enhance nitric oxide signaling, leading to improved physical function in healthy and diseased populations, but its safety and biologic efficacy have not been evaluated in a critically ill population. We randomized 22 previously functional acute respiratory failure patients to either BRJ or placebo daily until day 14 or discharge. We measured blood nitrate and nitrite levels and quantified strength and physical function at intensive care unit (ICU) and hospital discharge. Participants were predominantly male (54%), aged 68.5 years with an APACHE III score of 62. BRJ increased plasma nitrate (mean 219.2 µM increase, p = 0.002) and nitrite levels (mean 0.144 µM increase, p = 0.02). We identified no adverse events. The unadjusted and adjusted effect sizes of the intervention on the short physical performance battery were small (d = 0.12 and d = 0.17, respectively). In this pilot trial, administration of BRJ was feasible and safe, increased blood nitrate and nitrate levels, but had a small effect on physical function. Future studies could evaluate the clinical efficacy of BRJ as a therapy to improve physical function in survivors of critical illness.

The relationship between self-report and performance-based measures of physical function following an ICU stay.

PURPOSE: To examine relationships between self-report and performance-based measures of physical function in ICU patients randomized to standardized rehabilitation therapy (SRT) or usual care (UC). METHODS: Physical function was assessed in 257 ICU patients using self-report (physical functioning scale of the SF-36 (SF-36 PFS)) and the functional performance inventory-short form (FPI-SF) as well as performance-based measures (Short Physical Performance Battery (SPPB)) and muscular strength (MS). Assessments were at hospital discharge, 2, 4, and 6 months. RESULTS: Correlations between self-report and performance-based measures were not significantly different between the two groups. When examining the entire cohort, a significant, but weak, correlation (r = 0.286) was found between the SF-36 PFS and the SPPB. At 2 months, moderate correlations were found between self-report and performance-based measures. The SF-36 PFS and FPI were significantly correlated with the SPPB (r = 0.536 and 0.553, respectively) and muscular strength (r = 0.413 and 0.431, respectively). Similar associations were seen at 4 and 6 months in both groups. CONCLUSION: Self-report and performance-based measures of physical function appear to assess different constructs at hospital discharge. Following recovery, these measures converge, but indicate different constructs are being assessed. As such, both self-report and performance-based measures of physical function should be used with ICU patients.