Exploration of muscle loss and metabolic state during prolonged critical illness: Implications for intervention?

Abstract

BackgroundMuscle wasting in the critically ill is up to 2% per day and delays patient recovery and rehabilitation. It is linked to inflammation, organ failure and severity of illness. The aims of this study were to understand the relationship between muscle depth loss, and nutritional and inflammatory markers during prolonged critical illness. Secondly, to identify when during critical illness catabolism might decrease, such that targeted nutritional strategies may logically be initiated.MethodsThis study was conducted in adult intensive care units in two large teaching hospitals. Patients anticipated to be ventilated for >48 hours were included. Serum C-reactive protein (mg/L), urinary urea (mmol/24h), 3-methylhistidine (μmol/24h) and nitrogen balance (g/24h) were measured on days 1, 3, 7 and 14 of the study. Muscle depth (cm) on ultrasound were measured on the same days over the bicep (bicep and brachialis muscle), forearm (flexor compartment of muscle) and thigh (rectus femoris and vastus intermedius).ResultsSeventy-eight critically ill patients were included with mean age of 59 years (SD: 16) and median Intensive care unit (ICU) length of stay of 10 days (IQR: 6–16). Starting muscle depth, 8.5cm (SD: 3.2) to end muscle depth, 6.8cm (SD: 2.2) were on average significantly different over 14 days, with mean difference -1.67cm (95%CI: -2.3 to -1cm), p<0.0001. Protein breakdown and inflammation continued over 14 days of the study.ConclusionOur patients demonstrated a continuous muscle depth loss and negative nitrogen balance over the 14 days of the study. Catabolism remained dominant throughout the study period. No obvious ‘nutritional tipping point” to identify anabolism or recovery could be identified in our cohort. Our ICU patient cohort is one with a moderately prolonged stay. This group showed little consistency in data, reflecting the individuality of both disease and response. The data are consistent with a conclusion that a time based assumption of a tipping point does not exist.Trial registrationInternational Standard Randomised Controlled Trial Number: ISRCTN79066838. Registration 25 July 2012.

Medical high-protein nutrition therapy and loss of muscle mass in adult ICU patients: A randomized controlled trial

“…Consequently, a considerable and life-threatening loss of muscle mass occurs [2]. Medical therapeutic measures such as long-term sedation and mechanical ventilation during ICU stay can further enhance this muscle degradation (up to 2 % muscle mass per day [3]) leading to clinically relevant symptoms known as ICUacquired weakness (ICUAW) [2,4,5], a clinical symptom that is classified as a secondary disorder [6]. If left unabated, these circumstances might strongly affect long-term patient outcomes [5,7].…”

Feasibility of achieving different protein targets using a hypocaloric high-protein enteral formula in critically ill patients

“…This process is not easy to attenuate or even to stop despite large amounts of protein administered. Wandraq [ 27 ] showed a muscle loss of more than 25% in 14 days despite the administration of 1.2 g/kg/d of protein. Nitrogen balance remained negative at − 7 g/day.…”

Lessons Learned in Nutrition Therapy in Patients With Severe COVID‐19

“…Muscle weakness is universal and is particularly marked in patients with prolonged ICU stay. 40 Some key opinion leaders suggest that providing increased protein and energy is indicated for all patients during the recovery phase, aiming to achieve a restoration of muscle mass. This is certainly the case for the patient that can participate in active rehabilitation.…”

“…Despite clinicians’ best attempt, all patients lose muscle mass and are in negative nitrogen balance during their ICU stay. Muscle weakness is universal and is particularly marked in patients with prolonged ICU stay 40 …”