Impact of ICU-acquired weakness on post-ICU physical functioning

Impact of ICU-acquired weakness on post-ICU physical functioning: a follow-up study. Critical Care 2015, 19: 196


Wieske, L., et al.


http://ccforum.com/content/pdf/s13054-015-0937-2.pdf


Intensive Care Unit – acquired weakness (ICU-AW) is thought to mediate physical impairments in survivors of critical illness but few studies have investigated this thoroughly. The purpose was to investigate differences in post-ICU mortality and physical functioning between patients with and without ICU-AW at 6 months after ICU discharge. Method ICU patients, mechanically ventilated ≥2 days, were included in a single center prospective observational cohort study. ICU-AW was diagnosed when the average Medical Research Council (MRC) score was <4 in awake and attentive patients. Post-ICU mortality was recorded until 6 months after ICU discharge; in surviving patients physical functioning was assessed using the Short-Form Health Survey (SF-36) physical functioning (PF) domain. The independent effect of ICU-AW on post-ICU mortality was analyzed using a multivariable Cox proportional hazards model. The independent effect of ICU-AW on the PF domain score was analyzed using a multivariable linear regression model. Results: 156 patients were included, of whom 80 with ICU-AW. Twenty-three patients died in the ICU (20 with ICU-AW); during the 6 months follow-up after ICU discharge another 25 patients died (17 with ICU-AW). PF scores were available for 96 survivors (39 patients with ICU-AW). ICU-AW was independently associated with an increase in post-ICU mortality (HR 3.6 (95% CI: 1.3 to 9.8); p:0.01) and with a decrease in physical functioning (β: -16.7 points (95% CI: -30.2 to -3.1); p:0.02). Conclusion: ICU-AW is independently associated with higher post-ICU mortality and with clinically relevant lower physical functioning in survivors at 6 months after ICU discharge.

A new two-tier strength assessment approach to the diagnosis of weakness in intensive care

A new two-tier strength assessment approach to the diagnosis of weakness in intensive care: An observational study. Critical Care, 2015, 19: 52 

Parry, S.M., et al.

http://ccforum.com/content/pdf/s13054-015-0780-5.pdf

Intensive care unit acquired weakness (ICUAW) is a significant problem. There is currently widespread variability in the methods used for manual muscle testing and handgrip dynamometry (HGD) to diagnose ICUAW. This study was conducted in two parts. The aims of this study were: to determine the inter-rater reliability and agreement of manual muscle strength testing using both isometric and through range techniques using the Medical Research Council sum-score and a new four-point scale, and to examine the validity of HGD and determine a cutoff score for the diagnosis of ICUAW for the new four-point scale.Part one involved evaluation of muscle strength by two physical therapists in 29 patients ventilated >48 hours. Manual strength testing was performed by both physical therapists using two techniques: isometric and through-range; and two scoring systems: traditional sixpoint Medical Research Council scale and a new collapsed four-point scale. Part two involved assessment of handgrip strength conducted on 60 patients. A cut-off score for ICUAW was identified for the new four-point scoring system. The incidence of ICU-AW was 42% (n = 25/60) in this study (based on HGD). In part one the highest reliability and agreement was observed for the isometric technique using the fourpoint scale (intraclass correlation coefficient = 0.90: Kappa = 0.72 respectively). Differences existed between isometric and through-range scores (mean difference = 1.76 points, P = 0.005). In part two, HGD had a sensitivity of 0.88 and specificity of 0.80 for diagnosing ICUAW. A cut-off score of 24/36 points was identified for the four-point scale. The isometric technique is recommended with reporting on a collapsed four-point scale. Because HGD is easy to perform and sensitive we recommend a new two-tier approach to diagnosing ICUAW that first tests handgrip strength with follow-up strength assessment using the isometric technique for muscle strength testing if handgrip strength falls below cutoff scores. Whilst our results for the four-point scale are encouraging, further research is required to confirm the findings of this study and determine the validity of the four-point scoring system and cut off score developed.

ICU-acquired weakness and recovery from critical illness

ICU-acquired weakness and recovery from critical illness.  N Engl J of Med, 2014, 371:287-288

Kress, JP and Hall, JB.

http://www.nejm.org/doi/pdf/10.1056/NEJMra1209390