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

Abstract

Purpose of Review We have significantly improved hospital mortality from sepsis and critical illness in last 10 years, however over this same period we have tripled the number of “ICU survivors” going to rehabilitation. Further, as up to half the deaths in the first year following ICU admission occur post-ICU discharge, it is unclear how many of these patients ever returned home or a meaningful quality of life (QoL). For those who do survive, recent data reveals many “ICU survivors” will suffer significant functional impairment or Post-ICU Syndrome (PICS). Thus, new innovative metabolic and exercise interventions to address PICS are urgently needed. These should focus on optimal nutrition and lean body mass (LBM) assessment, targeted nutrition delivery, anabolic/anti-catabolic strategies, and utilization of personalized exercise intervention techniques, such as utilized by elite athletes to optimize preparation and recovery from critical care. Recent findings New data for novel LBM analysis technique such as CT scan and ultrasound analysis of lean body mass are available showing objective measures of LBM now becoming more practical for predicting metabolic reserve and effectiveness of nutrition/exercise interventions. 13C-breath testing is a novel technique under study to predict infection earlier and predict over- and under-feeding to target nutrition delivery. New technologies utilized routinely by athletes such as muscle glycogen ultrasound also show promise. Finally, the role of personalized cardiopulmonary exercise testing (CPET) to target pre-operative exercise optimization and post-ICU recovery are becoming reality. Summary New innovative techniques are demonstrating promise to target recovery from PICS utilizing a combination of objective LBM and metabolic assessment, targeted nutrition interventions, personalized exercise interventions for prehabilitation and post-ICU recovery. These interventions should provide hope that we will soon begin to create more “survivors” and fewer victim's post-ICU care.

Assessment of Muscle Wasting in Long-Stay ICU Patients Using a New Ultrasound Protocol

“…Sepsis, difficult ventilator liberation, and prolonged mechanical ventilation are among the well-known risk factors associated with neuromuscular acquired weakness [26]. Aggressive nutritional therapy and early exercise should be considered to prevent muscle wasting or to maintain muscle, although they may fail when applied early in critically ill patients [2,3]. However, BMI assessment does not indicate the muscle quality and quantity of wasting in these patients.…”

“…Moreover, increased energy and protein administration within the first acute-phase admission week does not seem to prevent muscle wasting or promote muscle preservation. Protein-loading and exercise, although used successfully to treat frailty in older patients [1], may fail in the still not well-defined group of severely catabolic patients, if applied as a standard treatment [2,3].…”

Tailoring nutrition therapy to illness and recovery

“…But, as always, this increase in calorie delivery should be targeted with objective data when possible via use of improved metabolic cart technology. In the future, great promise seems to exist for bedside 13 C/ 12 C breath carbon ratio mass spectroscopy [ 46 , 47 ] to assist in direct objective measurement of overfeeding and underfeeding. Finally, we must learn to target and incorporate nutritional therapies such as vitamin D, probiotics, and anabolic/anti-catabolic agents to optimize our patients’ chance to survive and thrive against all evolutionary odds.…”

Current Evidence about Nutrition Support in Cardiac Surgery Patients—What Do We Know?

“…Concerns regarding PN are the potential risk of overfeeding with hyperglycemia, elevated liver enzymes and increased rate of blood stream infections. Current evidence remains inconclusive, but there seems to be no difference regarding clinical outcome between EN and PN [ 91 , 92 , 93 ]. However, in the EPaNIC Trial of Casaer et al, a lower rate of infection was observed with a later achievement of caloric targets [ 94 ].…”