Muscle Weakness and 5-Year Survival in Acute Respiratory Distress Syndrome Survivors*

Abstract

Objective To longitudinally evaluate the association of post-ICU muscle weakness and associated trajectories of weakness over time with 5-year survival. Design Longitudinal prospective cohort study over 5 years of follow-up Patients 156 acute respiratory distress syndrome (ARDS) survivors Setting 13 ICUs in 4 hospitals in Baltimore, MD Interventions None Measurements and Main Results Strength was evaluated with standardized manual muscle testing using the Medical Research Council sumscore (range: 0–60, higher is better), with post-ICU weakness defined as sumscore <48. Muscle strength was assessed at hospital discharge and at 3, 6, 12, 24, 36, and 48 months after ARDS. At discharge, 38% of patients had muscle weakness. Every 1 point increase in sumscore at discharge was associated with improved survival (hazard ratio (95% confidence interval) 0.96 (0.94–0.98)), with similar findings longitudinally (0.95, 0.93–0.98). Having weakness at discharge was associated with worse 5-year survival (1.75, 1.01–3.03); but the association was attenuated (1.54, 0.82–2.89) when evaluated longitudinally over follow-up. Occurring in 50% of patients during follow-up, persisting and resolving trajectories of muscle weakness were associated with worse survival (3.01, 1.12–8.04; and 3.14, 1.40–7.03, respectively) compared to a trajectory of maintaining no muscle weakness. Conclusions At hospital discharge, >1/3 of ARDS survivors had muscle weakness. Greater strength at discharge and throughout follow-up was associated with improved 5-year survival. In patients with post-ICU weakness, both persisting and resolving trajectories, were commonly experienced and associated with worse survival during follow-up.

Pulmonary rehabilitation, physical activity, respiratory failure and palliative respiratory care

“…Early mobilisation needs to be targeted at the appropriate ICU population, with current data supporting application very early in the course of critical illness. The severity of the acute illness determines the degree of muscle wasting,51 with age, ICU length of stay, systemic inflammation and chronic health prior to critical illness determining the trajectory of recovery 58. In addition, decreased mitochondrial biogenesis and dysregulated lipid oxidation contribute to a compromised skeletal muscle bioenergetic status with intramuscular inflammation associated with impaired anabolic recovery60 and development of ICU-acquired weakness 61.…”

Muscle mass and physical recovery in ICU: innovations for targeting of nutrition and exercise

“…Muscle wasting and weakness are also major contributors to PICS [4*, 13*]. This is not unsurprising, as these parameters reflect “metabolic reserve”, which is effected by physical activity, nutrition, chronic disease and is tightly linked to function.…”

“…This technique has been used in wild life ecology studies to determine metabolic fuel usage in birds during different types of flight. For example, humming birds rely primarily on carbohydrate source during hovering flight while migratory birds rely on stored lipids to power long range flights over may thousands of kilometers[39**, 40]. More recently this technique has been applied in humans to understand metabolic fuel usage in health and disease.…”

“…We also know that up to 40% of mortality within the first year of ICU stay occurs following ICU discharge [2]. Unfortunately for those who do survive, nearly half of the survivors will not return to work in the first year post-discharge [3**], often due to post-intensive care syndrome (PICS) and weakness post-ICU[4*]. As a result, many leading experts are calling for future ICU trials to not focus on mortality as the primary endpoint, but rather to focus on Quality of Life QoL [5**], physical function and addressing the epidemic of PICS [1, 6].…”

Optimizing sedation in the ICU: the eCASH concept

“…(17) Restricted mobilization of ICU patients as a result of deep sedation is likely to increase the development of ICU-acquired weakness (18,19), which can have prolonged effects on long-term outcomes. (20) In a study of 192 patients in 12 ICUs in New Zealand and Australia in 2012/2013, two-thirds of patients were "deeply" sedated (Richmond Agitation Sedation Scale [RASS] -3 to -5) and two-thirds of the patients did not receive early mobilization; the main reason for lack of mobilization was the degree of sedation. (14) Similar findings were reported in a one-day point prevalence study in 116 German ICUs: only 24% of mechanically ventilated patients and just 8% of patients with an endotracheal tube were mobilized out-of-bed and the biggest barrier to mobilization was deep sedation.…”