Winning the war against ICU-acquired weakness: new innovations in nutrition and exercise physiology

Abstract

Over the last 10 years we have significantly reduced hospital mortality from sepsis and critical illness. However, the evidence reveals that over the same period we have tripled the number of patients being sent to rehabilitation settings. Further, given that as many as half of the deaths in the first year following ICU admission occur post ICU discharge, it is unclear how many of these patients ever returned home. For those who do survive, the latest data indicate that 50-70% of ICU "survivors" will suffer cognitive impairment and 60-80% of "survivors" will suffer functional impairment or ICU-acquired weakness (ICU-AW). These observations demand that we as intensive care providers ask the following questions: "Are we creating survivors ... or are we creating victims?" and "Do we accomplish 'Pyrrhic Victories' in the ICU?" Interventions to address ICU-AW must have a renewed focus on optimal nutrition, anabolic/anticatabolic strategies, and in the future employ the personalized muscle and exercise evaluation techniques utilized by elite athletes to optimize performance. Specifically, strategies must include optimal protein delivery (1.2-2.0 g/kg/day), as an athlete would routinely employ. However, as is clear in elite sports performance, optimal nutrition is fundamental but alone is often not enough. We know burn patients can remain catabolic for 2 years post burn; thus, anticatabolic agents (i.e., beta-blockers) and anabolic agents (i.e., oxandrolone) will probably also be essential. In the near future, evaluation techniques such as assessing lean body mass at the bedside using ultrasound to determine nutritional status and ultrasound-measured muscle glycogen as a marker of muscle injury and recovery could be utilized to help find the transition from the acute phase of critical illness to the recovery phase. Finally, exercise physiology testing that evaluates muscle substrate utilization during exercise can be used to diagnose muscle mitochondrial dysfunction and to guide a personalized ideal heart rate, assisting in recovery of muscle mitochondrial function and functional endurance post ICU. In the end, future ICU-AW research must focus on using a combination of modern performance-enhancing nutrition, anticatabolic/anabolic interventions, and muscle/exercise testing so we can begin to create more "survivors" and fewer victims post ICU care.

Figures

Figure 1

A ... B ... C ... D ... E ... F ... G ... for post-ICU QOL.QOL quality of life.

Figure 2

Muscle glycogen scores via ultrasound.

Figure 3

Skeletal muscle glycogen content score via ultrasound.

Figure 4

Lean Body Mass Loss Over 20 days following surgery and critical illness (20 kg over 20 days = 1 kg lean body mass lost/day).

Figure 5

Phases of Critical Care and Metabolic Therapy in ICU. BCAA-Branch Chain Amino Acids. Dysfx-Dysfunction. GH-Growth Hormone. GLN-Glutamine. TPN-Total Parenteral Nutrition

Figure 6

a: Exercise Physiology Testing in World Class Athlete. b: Exercise Physiology Testing in Obesity/Type 2 Diabetes. CHO-Carbohydrate. HR-Heart Rate.

Figure 7

A - Exercise Physiology Testing in Burn Patient Prior to Metabolic and Exercise Therapy. B - Exercise Physiology Testing in Burn Patient Following Metabolic and Exercise Therapy. CHO-Carbohydrate. Ox-Oxidation.