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BACKGROUND: Muscle 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. METHODS: This 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). RESULTS: Seventy-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. CONCLUSION: Our 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 REGISTRATION: International Standard Randomised Controlled Trial Number: ISRCTN79066838. Registration 25 July 2012.
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Proteína C-Reactiva/metabolismo , Citidina/análogos & derivados , Tiempo de Internación , Músculo Esquelético , Atrofia Muscular , Urea/orina , Adulto , Anciano , Enfermedad Crítica , Citidina/orina , Femenino , Humanos , Masculino , Persona de Mediana Edad , Músculo Esquelético/metabolismo , Músculo Esquelético/fisiopatología , Atrofia Muscular/sangre , Atrofia Muscular/fisiopatología , Atrofia Muscular/orinaRESUMEN
BACKGROUND: Loss of skeletal muscle mass and muscle weakness are common in a variety of clinical conditions with both wasting and weakness associated with an impairment of physical function. ß-Hydroxy-ß-methylbutyrate (HMB) is a nutrition supplement that has been shown to favorably influence muscle protein turnover and thus potentially plays a role in ameliorating skeletal muscle wasting and weakness. OBJECTIVES: The aim of this study was to investigate the efficacy of HMB alone, or supplements containing HMB, on skeletal muscle mass and physical function in a variety of clinical conditions characterized by loss of skeletal muscle mass and weakness. METHODS: A systematic review and meta-analysis of randomized controlled trials reporting outcomes of muscle mass, strength, and physical function was performed. Two reviewers independently performed screening, data extraction, and risk-of-bias assessment. Outcome data were synthesized through meta-analysis with the use of a random-effects model and data presented as standardized mean differences (SMDs). RESULTS: Fifteen randomized controlled trials were included, involving 2137 patients. Meta-analysis revealed some evidence to support the effect of HMB alone, or supplements containing HMB, on increasing skeletal muscle mass (SMD = 0.25; 95% CI: -0.00, 0.50; z = 1.93; P = 0.05; I2 = 58%) and strong evidence to support improving muscle strength (SMD = 0.31; 95% CI: 0.12, 0.50; z = 3.25; P = 0.001; I2 = 0%). Effect sizes were small. No effect on bodyweight (SMD = 0.16; 95% CI: -0.08, 0.41; z = 1.34; P = 0.18; I2 = 67%) or any other outcome was found. No study was considered to have low risk of bias in all categories. CONCLUSION: HMB, and supplements containing HMB, increased muscle mass and strength in a variety of clinical conditions, although the effect size was small. Given the bias associated with many of the included studies, further high-quality studies should be undertaken to enable interpretation and translation into clinical practice. The trial was registered on PROSPERO as CRD42017058517.
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Debilidad Muscular/tratamiento farmacológico , Músculo Esquelético/efectos de los fármacos , Valeratos/administración & dosificación , Adulto , Anciano , Anciano de 80 o más Años , Suplementos Dietéticos/análisis , Femenino , Humanos , Masculino , Persona de Mediana Edad , Fuerza Muscular/efectos de los fármacos , Debilidad Muscular/fisiopatología , Músculo Esquelético/crecimiento & desarrollo , Músculo Esquelético/fisiopatología , Ensayos Clínicos Controlados Aleatorios como Asunto , Adulto JovenRESUMEN
The lack of benefit from randomised controlled trials has resulted in significant controversy regarding the role of nutrition during critical illness in terms of long-term recovery and outcome. Although methodological caveats with a failure to adequately appreciate biological mechanisms may explain these disappointing results, it must be acknowledged that nutritional support during early critical illness, when considered alone, may have limited long-term functional impact.This narrative review focuses specifically on recent clinical trials and evaluates the impact of nutrition during critical illness on long-term physical and functional recovery.Specific focus on the trial design and methodological limitations has been considered in detail. Limitations include delivery of caloric and protein targets, patient heterogeneity, short duration of intervention, inappropriate clinical outcomes and a disregard for baseline nutritional status and nutritional intake in the post-ICU period.With survivorship at the forefront of critical care research, it is imperative that nutrition studies carefully consider biological mechanisms and trial design because these factors can strongly influence outcomes, in particular long-term physical and functional outcome. Failure to do so may lead to inconclusive clinical trials and consequent rejection of the potentially beneficial effects of nutrition interventions during critical illness.
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Enfermedad Crítica/rehabilitación , Apoyo Nutricional/métodos , Recuperación de la Función , Ingestión de Energía/fisiología , Humanos , Estado Nutricional/fisiología , Factores de TiempoRESUMEN
OBJECTIVES: Sarcopenia refers to the involuntary loss of skeletal muscle and is a predictor of physical disability/mortality. Its pathogenesis is poorly understood, although roles for altered hypoxic signaling, oxidative stress, adipokines and inflammatory mediators have been suggested. Sarcopenia also occurs upon exposure to the hypoxia of high altitude. Using data from the Caudwell Xtreme Everest expedition we therefore sought to analyze the extent of hypoxia-induced body composition changes and identify putative pathways associated with fat-free mass (FFM) and fat mass (FM) loss. METHODS: After baseline testing in London (75m), 24 investigators ascended from Kathmandu (1300m) to Everest base camp (EBC 5300m) over 13 days. Fourteen investigators climbed above EBC, eight of whom reached the summit (8848m). Assessments were conducted at baseline, during ascent and after one, six and eight week(s) of arrival at EBC. Changes in body composition (FM, FFM, total body water, intra- and extra-cellular water) were measured by bioelectrical impedance. Biomarkers of nitric oxide and oxidative stress were measured together with adipokines, inflammatory, metabolic and vascular markers. RESULTS: Participants lost a substantial, but variable, amount of body weight (7.3±4.9kg by expedition end; p<0.001). A progressive loss of both FM and FFM was observed, and after eight weeks, the proportion of FFM loss was 48% greater than FM loss (p<0.008). Changes in protein carbonyls (p<0.001) were associated with a decline in FM whereas 4-hydroxynonenal (p<0.001) and IL-6 (p<0.001) correlated with FFM loss. GLP-1 (r=-0.45, p<0.001) and nitrite (r=-0.29, p<0.001) concentration changes were associated with FFM loss. In a multivariate model, GLP-1, insulin and nitrite were significant predictors of FFM loss while protein carbonyls were predicted FM loss. CONCLUSIONS: The putative role of GLP-1 and nitrite as mediators of the effects of hypoxia on FFM is an intriguing finding. If confirmed, nutritional and pharmacological interventions targeting these pathways may offer new avenues for prevention and treatment of sarcopenia.
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Altitud , Hipoxia/complicaciones , Sarcopenia/etiología , Adulto , Biomarcadores/sangre , Composición Corporal , Femenino , Péptido 1 Similar al Glucagón/sangre , Humanos , Hipoxia/sangre , Hipoxia/fisiopatología , Masculino , Persona de Mediana Edad , Nitritos/sangre , Estrés Oxidativo , Sarcopenia/fisiopatologíaRESUMEN
INTRODUCTION: The nutritional status of patients in the intensive care unit (ICU) appears to decline not only during their stay in the ICU but also after discharge from the ICU. Recent evidence suggests that gut released peptides, such as ghrelin and peptide YY (PYY) regulate the initiation and termination of meals and could play a role in the altered eating behaviour of sick patients. The aim of this study was to assess the patterns of ghrelin and PYY levels during the stay of ICU patients in hospital. METHODS: Sixteen ICU patients (60 +/- 4.7 years, body mass index (BMI) 28.1 +/- 1.7 kg/m2 (mean +/- standard error of the mean)) underwent fasting blood sample collections on days 1, 3, 5, 14, 21 and 28 of their stay at Hammersmith and Charing Cross Hospitals. Changes in appetite and biochemical and anthropometric markers of nutritional status were recorded. A comparison was made to a group of 36 healthy volunteers matched for age and BMI (54.3 +/- 2.9 years, p = 0.3; BMI 25.8 +/- 0.8 kg/m2 p = 0.2). RESULTS: Compared to healthy subjects, ICU patients exhibited a significantly lower level of ghrelin (day one 297.8 +/- 76.3 versus 827.2 +/- 78.7 pmol/l, p < 0.001) during their stay in the ICU. This tended to rise to the normal level during the last three weeks of hospital stay. Conversely, ICU patients showed a significantly higher level of PYY (day one 31.5 +/- 9.6 versus 11.3 +/- 1.0 pmol/l, p < 0.05) throughout their stay in the ICU and on the ward, with a downward trend to the normal level during the last three weeks of stay. CONCLUSIONS: Results from our study show high levels of PYY and low levels of ghrelin in ICU patients compared to healthy controls. There appears to be a relationship between the level of these gut hormones and nutritional intake.