Anabolic and anticatabolic agents in critical care

Metformin is associated with reduced risk of mortality and morbidity in burn patients compared to insulin

PURPOSE

The standard of care for burned patients experiencing hyperglycemia associated with the hypermetabolic response is insulin therapy. Insulin treatment predisposes burn patients to hypoglycemia, which increases morbidity and mortality. Metformin has been suggested as an alternative to insulin therapy for glycemic control in burn patients given its safety profile, but further research is warranted. This study investigated whether metformin use in burn patients is associated with improved glycemic control and morbidity/mortality outcomes compared to insulin use alone.

MATERIALS AND METHODS

Using the TriNetX database, we conducted a retrospective study of burned patients who were administered insulin, metformin, or both within one week of injury. Demographic, comorbidity, and burn severity information were collected. Patients were categorized by treatment type, propensity score-matched, and compared for the following outcomes within 3 months: hyperglycemia, hypoglycemia, sepsis, lactic acidosis, and death. Statistical significance was set a priori at p ≤ 0.05.

RESULTS

The insulin cohort was at increased risk for all outcomes (all p < 0.0001) compared to the metformin cohort, and an increased risk for sepsis, lactic acidosis, and death (all p ≤ 0.0002) compared to the insulin/metformin combination cohort. When compared to the metformin cohort, the combination cohort was at increased risk for all outcomes (all p ≤ 0.0107) except death.

CONCLUSIONS

Treatment with metformin after burn is associated with a reduced risk of morbidity and mortality compared to insulin. The combination of insulin and metformin is no more effective in reducing the risk of hyperglycemia and hypoglycemia than insulin alone but is less effective than metformin alone.

Post-intensive care syndrome follow-up system after hospital discharge: a narrative review

BACKGROUND

Post-intensive care syndrome (PICS) is the long-lasting impairment of physical functions, cognitive functions, and mental health after intensive care. Although a long-term follow-up is essential for the successful management of PICS, few reviews have summarized evidence for the efficacy and management of the PICS follow-up system.

MAIN TEXT

The PICS follow-up system includes a PICS follow-up clinic, home visitations, telephone or mail follow-ups, and telemedicine. The first PICS follow-up clinic was established in the U.K. in 1993 and its use spread thereafter. There are currently no consistent findings on the efficacy of PICS follow-up clinics. Under recent evidence and recommendations, attendance at a PICS follow-up clinic needs to start within three months after hospital discharge. A multidisciplinary team approach is important for the treatment of PICS from various aspects of impairments, including the nutritional status. We classified face-to-face and telephone-based assessments for a PICS follow-up from recent recommendations. Recent findings on medications, rehabilitation, and nutrition for the treatment of PICS were summarized.

CONCLUSIONS

This narrative review aimed to summarize the PICS follow-up system after hospital discharge and provide a comprehensive approach for the prevention and treatment of PICS.

The Good, the Bad, and the Serum Creatinine: Exploring the Effect of Muscle Mass and Nutrition

Muscle wasting (sarcopenia) is one of the hallmarks of critical illness. Patients admitted to intensive care unit develop sarcopenia through increased protein catabolism, a decrease in protein syntheses, or both. Among the factors known to promote wasting are chronic inflammation and cytokine imbalance, insulin resistance, hypermetabolism, and malnutrition. Moreover, muscle wasting, known to develop in chronic kidney disease patients, is a harmful consequence of numerous complications associated with deteriorated renal function. Plenty of published data suggest that serum creatinine (SCr) reflects increased kidney damage and is also related to body weight. Based on the concept that urea and creatinine are nitrogenous end products of metabolism, the urea:creatinine ratio (UCR) could be applied but with limited clinical usability in case of kidney damage, hypovolemia, excessive, or protein intake, where UCR can be high and independent of catabolism. Recent data suggest that the sarcopenia index should be considered an alternative to serum creatinine. It is more reliable in estimating muscle mass than SCr. However, the optimal biomarker of catabolism is still an unresolved issue. The SCr is not a promising biomarker for renal function and muscle mass based on the influence of several factors. The present review highlights recent findings on the limits of SCr as a surrogate marker of renal function and the assessment modalities of nutritional status and muscle mass measurements.

Personalized nutrition therapy in critical care: 10 expert recommendations

Personalization of ICU nutrition is essential to future of critical care. Recommendations from American/European guidelines and practice suggestions incorporating recent literature are presented. Low-dose enteral nutrition (EN) or parenteral nutrition (PN) can be started within 48 h of admission. While EN is preferred route of delivery, new data highlight PN can be given safely without increased risk; thus, when early EN is not feasible, provision of isocaloric PN is effective and results in similar outcomes. Indirect calorimetry (IC) measurement of energy expenditure (EE) is recommended by both European/American guidelines after stabilization post-ICU admission. Below-measured EE (~ 70%) targets should be used during early phase and increased to match EE later in stay. Low-dose protein delivery can be used early (~ D1-2) (< 0.8 g/kg/d) and progressed to ≥ 1.2 g/kg/d as patients stabilize, with consideration of avoiding higher protein in unstable patients and in acute kidney injury not on CRRT. Intermittent-feeding schedules hold promise for further research. Clinicians must be aware of delivered energy/protein and what percentage of targets delivered nutrition represents. Computerized nutrition monitoring systems/platforms have become widely available. In patients at risk of micronutrient/vitamin losses (i.e., CRRT), evaluation of micronutrient levels should be considered post-ICU days 5-7 with repletion of deficiencies where indicated. In future, we hope use of muscle monitors such as ultrasound, CT scan, and/or BIA will be utilized to assess nutrition risk and monitor response to nutrition. Use of specialized anabolic nutrients such as HMB, creatine, and leucine to improve strength/muscle mass is promising in other populations and deserves future study. In post-ICU setting, continued use of IC measurement and other muscle measures should be considered to guide nutrition. Research on using rehabilitation interventions such as cardiopulmonary exercise testing (CPET) to guide post-ICU exercise/rehabilitation prescription and using anabolic agents such as testosterone/oxandrolone to promote post-ICU recovery is needed.

Metabolic and Nutritional Support

Hypermetabolism is a hallmark of larger burn injuries. The hypermetabolic response is characterized by marked and sustained increases in catecholamines, glucocorticoids, and glucagon. There is an increasing body of literature for nutrition and metabolic treatment and supplementation to counter the hypermetabolic and catabolic response secondary to burn injury. Early and adequate nutrition is key in addition to adjunctive therapies, such as oxandrolone, insulin, metformin, and propranolol. The duration of administration of anabolic agents should be at minimum for the duration of hospitalization, and possibly up to 2 to 3 years postburn.

(Mal)nutrition in critical illness and beyond: a narrative review

Close liaison with ICU-trained dietitians and early initiation of nutrition is a fundamental principle of care of critically ill patients- this should be done while monitoring closely for refeeding syndrome. Enteral nutrition delivered by volumetric pumps should be used where possible, though parenteral nutrition should be started early in patients with high nutritional risk factors. Malnutrition and loss of muscle mass are common in patients who are admitted to ICUs and are prognostic for patient-centred outcomes including complications and mortality. Obesity is part of that story, and isocaloric and high-protein provision of nutrition is important in this group of patients who comprise a growing proportion of people treated. Assessing protein stores and appropriate dosing is, however, challenging in all groups of patients. It would be beneficial to develop strategies to reduce muscle wasting as well; various strategies including amino acid supplementation, ketogenic nutrition and exercise have been trialled, but the quality of data has been inadequate to address this phenomenon. Nutritional targets are rarely achieved in practice, and all ICUs should incorporate clear guidelines to help address this. These should include local nutritional and fasting guidelines and for the management of feed intolerance, early access to post-pyloric feeding and a multidisciplinary framework to support the importance of nutritional education.

Androgens' Role in Severity and Mortality Rates of COVID-19

By the end of December 2019 new corona virus began to spread from Wuhan, China and caused a worldwide pandemic. COVID-19 deaths and prevalence represented sex discrepant patterns with higher rate of deaths and infection in males than females which could be justified by androgen-mediated mechanisms. This review aimed to assess the role of androgens in COVID-19 severity and mortality. Androgens increase expressions of Type II transmembrane Serine Protease (TMPRSS2) and Angiotensin Converting Enzyme 2 (ACE2), which both facilitate new corona virus entry into host cell and their expression is higher in young males than females. According to observational studies, prevalence of COVID-19 infections and deaths was more in androgenic alopecic patients than patients without androgenic alopecia. The COVID-19 mortality rates in aged men (>60 years) were substantially higher than aged females and even young males caused by high inflammatory activities such as cytokine storm due to hypogonadism in this population. Use of anti-androgen and TMPRSS2 inhibitor drugs considerably modified COVID-19 symptoms. Androgen deprivation therapy also improved COVID-19 symptoms in prostate cancer: overall the role of androgens in severity of COVID-19 and its associated mortality seemed to be very important. So, more studies in variety of populations are required to define the absolute role of androgens.

Exercise Limitation after Critical Versus Mild COVID-19 Infection: A Metabolic Perspective

Exercise limitation in COVID-19 survivors is poorly explained. In this retrospective study, cardiopulmonary exercise testing (CPET) was coupled with an oxidative stress assessment in COVID-19 critically ill survivors (ICU group). Thirty-one patients were included in this group. At rest, their oxygen uptake (VO₂) was elevated (8 [5.6–9.7] mL/min/kg). The maximum effort was reached at low values of workload and VO₂ (66 [40.9–79.2]% and 74.5 [62.6–102.8]% of the respective predicted values). The ventilatory equivalent for carbon dioxide remained within normal ranges. Their metabolic efficiency was low: 15.2 [12.9–17.8]%. The 50% decrease in VO₂ after maximum effort was delayed, at 130 [120–170] s, with a still-high respiratory exchange ratio (1.13 [1–1.2]). The blood myeloperoxidase was elevated (92 [75.5–106.5] ng/mL), and the OSS was altered. The CPET profile of the ICU group was compared with long COVID patients after mid-disease (MLC group) and obese patients (OB group). The MLC patients (n = 23) reached peak workload and predicted VO₂ values, but their resting VO₂, metabolic efficiency, and recovery profiles were similar to the ICU group to a lesser extent. In the OB group (n = 15), no hypermetabolism at rest was observed. In conclusion, the exercise limitation after a critical COVID-19 bout resulted from an altered metabolic profile in the context of persistent inflammation and oxidative stress. Altered exercise and metabolic profiles were also observed in the MLC group. The contribution of obesity on the physiopathology of exercise limitation after a critical bout of COVID-19 did not seem relevant.

Prevalence of nutritional risk and malnutrition during and after hospitalization for COVID-19 infection: Preliminary results of a single-centre experience

Background & aims

The effect of the COVID-19 infection on nutritional status is not well established. Worldwide epidemiological studies have begun to investigate the incidence of malnutrition during hospitalization for COVID-19. The prevalence of malnutrition during follow-up after COVID-19 infection has not been investigated yet. The primary objective of the present study was to estimate the prevalence of the risk of malnutrition in hospitalized adult patients with COVID-19, re-evaluating their nutritional status during follow-up after discharge. The secondary objective was to identify factors that may contribute to the onset of malnutrition during hospitalization and after discharge.

Methods

We enrolled 142 COVID-19 patients admitted to Careggi University Hospital. Nutritional parameters were measured at three different timepoints for each patient: upon admission to hospital, at discharge from hospital and 3 months after discharge during follow-up. The prevalence of both the nutritional risk and malnutrition was assessed. During the follow-up, the presence of nutritional impact symptoms (NIS) was also investigated. An analysis of the association between demographic and clinical features and nutritional status was conducted.

Results

The mean unintended weight loss during hospitalization was 7.6% (p < 0.001). A positive correlation between age and weight loss during hospitalization was observed (r = 0.146, p = 0.08). Moreover, for elderly patients (>61 years old), a statistically significant correlation between age and weight loss was found (r = 0.288 p = 0.05). Patients admitted to an Intensive Care Unit (ICU) or Intermediate Care Unit (IMCU) had a greater unintended weight loss than patients who stayed in a standard care ward (5.46% vs 1.19%; p < 0.001). At discharge 12 patients were malnourished (8.4%) according to the ESPEN definition. On average, patients gained 4.36 kg (p < 0.001) three months after discharge. Overall, we observed a weight reduction of 2.2% (p < 0.001) from the habitual weight measured upon admission. Patients admitted to an ICU/IMCU showed a higher MUST score three months after discharge (Cramer's V 0.218, p = 0.035). With regard to the NIS score, only 7 patients (4.9%) reported one or more nutritional problems during follow-up.

Conclusions

The identification of groups of patients at a higher nutritional risk could be useful with a view to adopting measures to prevent worsening of nutritional status during hospitalization. Admission to an ICU/IMCU, age and length of the hospital stay seem to have a major impact on nutritional status. Nutritional follow-up should be guaranteed for patients who lose more than 10% of their habitual weight during their stay in hospital, especially after admission to an ICU/IMCU.

Cardiopulmonary Exercise Testing in Critically Ill Coronavirus Disease 2019 Survivors: Evidence of a Sustained Exercise Intolerance and Hypermetabolism

Supplemental Digital Content is available in the text.

OBJECTIVES:

To investigate exercise capacity at 3 and 6 months after a prolonged ICU stay.

DESIGN:

Observational monocentric study.

SETTING:

A post-ICU follow-up clinic in a tertiary university hospital in Liège, Belgium.

PATIENTS:

Patients surviving an ICU stay greater than or equal to 7 days for a severe coronavirus disease 2019 pneumonia and attending our post-ICU follow-up clinic.

MEASUREMENTS AND MAIN RESULTS:

Cardiopulmonary and metabolic variables provided by a cardiopulmonary exercise testing on a cycle ergometer were collected at rest, at peak exercise, and during recovery. Fourteen patients (10 males, 59 yr [52–62 yr], all obese with body mass index > 27 kg/m²) were included after a hospital stay of 40 days (35–53 d). At rest, respiratory quotient was abnormally high at both 3 and 6 months (0.9 [0.83–0.96] and 0.94 [0.86–0.97], respectively). Oxygen uptake was also abnormally increased at 3 months (8.24 mL/min/kg [5.38–10.54 mL/min/kg]) but significantly decreased at 6 months (p = 0.013). At 3 months, at the maximum workload (67% [55–89%] of predicted workload), oxygen uptake peaked at 81% (64–104%) of predicted maximum oxygen uptake, with oxygen pulse and heart rate reaching respectively 110% (76–140%) and 71% (64–81%) of predicted maximum values. Ventilatory equivalent for carbon dioxide remains within normal ranges. The 50% decrease in oxygen uptake after maximum effort was delayed, at 130 seconds (115–142 s). Recovery was incomplete with a persistent anaerobic metabolism. At 6 months, no significant improvement was observed, excepting an increase in heart rate reaching 79% (72–95%) (p = 0.008).

CONCLUSIONS:

Prolonged reduced exercise capacity was observed up to 6 months in critically ill coronavirus disease 2019 survivors. This disability did not result from residual pulmonary or cardiac dysfunction but rather from a metabolic disorder characterized by a sustained hypermetabolism and an impaired oxygen utilization.

A Screening Tool to Detect Chronic Critically Ill Cardiac Surgery Patients at Risk for Low Levels of Testosterone and Somatomedin C: A Prospective Observational Pilot Study

Objective The neuroendocrine response to critical illness is dichotomous as it is adaptive during the acute phase then transitions to maladaptive as critical illness becomes prolonged in 25-30% of patients. Presently, monitoring all critically ill patients for endocrinopathies is not the standard of care. However, given the negative impact on patient prognosis, a need to identify those at risk for endocrinopathies, may exist. Thus, a screening tool to identify endocrinopathies along the somatotroph and gonadal axes in a cardiothoracic surgery population was developed. Methods A prospective observational pilot study was conducted in two cardiothoracic surgery intensive care units (ICU) within a multi-site healthcare system. Total testosterone and somatomedin C levels were obtained from 20 adult patients who remained in the ICU for greater than seven days after cardiothoracic surgery and were tolerating nutrition, had a risk of malnutrition and a mobility score of moderate to dependent assistance. Results Twenty patients were included for descriptive analysis (seven females). Thirteen patients tested low for total testosterone, with males more likely to have a testosterone-related endocrinopathy as compared to females (100% vs. 0 to 43%, p = 0.0072). A higher proportion of low somatomedin C levels was found in females than males (57% vs. 31%); however, the difference was not statistically significant (p = 0.251). Conclusions The screening tool used in this pilot study accurately predicted low total testosterone in all men and reasonably predicted low somatomedin C in a majority of women. However, the ability of the tool to predict low total testosterone in women and low somatomedin C in men is less certain. A gender-specific screening tool might be necessary to predict hormonal deficiencies.

Glucose Metabolism in Burns-What Happens?

Severe burns represent an important challenge for patients and medical teams. They lead to profound metabolic alterations, trigger a systemic inflammatory response, crush the immune defense, impair the function of the heart, lungs, kidneys, liver, etc. The metabolism is shifted towards a hypermetabolic state, and this situation might persist for years after the burn, having deleterious consequences for the patient's health. Severely burned patients lack energy substrates and react in order to produce and maintain augmented levels of glucose, which is the fuel "ready to use" by cells. In this paper, we discuss biological substances that induce a hyperglycemic response, concur to insulin resistance, and determine cell disturbance after a severe burn. We also focus on the most effective agents that provide pharmacological modulations of the changes in glucose metabolism.

Role of anabolic testosterone agents and structured exercise to promote recovery in ICU survivors

PURPOSE OF REVIEW

ICU survivors frequently suffer significant, prolonged physical disability. 'ICU Survivorship', or addressing quality-of-life impairments post-ICU care, is a defining challenge, and existing standards of care fail to successfully address these disabilities. We suggest addressing persistent catabolism by treatment with testosterone analogues combined with structured exercise is a promising novel intervention to improve 'ICU Survivorship'.

RECENT FINDINGS

One explanation for lack of success in addressing post-ICU physical disability is most ICU patients exhibit severe testosterone deficiencies early in ICU that drives persistent catabolism despite rehabilitation efforts. Oxandrolone is an FDA-approved testosterone analogue for treating muscle weakness in ICU patients. A growing number of trials with this agent combined with structured exercise show clinical benefit, including improved physical function and safety in burns and other catabolic states. However, no trials of oxandrolone/testosterone and exercise in nonburn ICU populations have been conducted.

SUMMARY

Critical illness leads to a catabolic state, including severe testosterone deficiency that persists throughout hospital stay, and results in persistent muscle weakness and physical dysfunction. The combination of an anabolic agent with adequate nutrition and structured exercise is likely essential to optimize muscle mass/strength and physical function in ICU survivors. Further research in ICU populations is needed.

Why does COVID-19 kill more elderly men than women? Is there a role for testosterone?

Background

Recent epidemiological data indicate that there may be a gender predisposition to COVID‐19, with men predisposed to being most severely affected, and older men accounting for most deaths.

Objectives

Provide a review of the research literature, propose hypotheses, and therapies based on the potential link between testosterone (T) and COVID‐19 induced mortality in elderly men.

Materials and Methods

A search of publications in academic electronic databases, and government and public health organization web sites on T, aging, inflammation, severe acute respiratory syndrome (SARS) due to coronavirus (CoV) 2 (SARS‐CoV‐2) infection, and COVID‐19 disease state and outcomes was performed.

Results

The link between T, the immune system, and male aging is well‐established, as is the progressive decline in T levels with aging. In women, T levels drop before menopause and variably increase with advanced age. Elevated IL‐6 is a characteristic biomarker of patients infected with COVID‐19 and has been linked to the development of the acute respiratory distress syndrome (ARDS). Thus far, half of the admitted COVID‐19 patients developed ARDS, half of these patients died, and elderly male patients have been more likely to develop ARDS and die. Low T is associated with ARDS. These data suggest that low T levels may exacerbate the severity of COVID‐19 infection in elderly men. It may also stand to reason that normal T levels may offer some protection against COVID‐19. SARS‐CoV‐2 binds to the angiotensin‐converting enzyme 2, present in high levels in the testis.

Conclusion

At present, it is not known whether low T levels in aging hypogonadal males create a permissive environment for severe responses to COVID‐19 infection or if the virus inhibits androgen formation. Given the preponderance of COVID‐19 related mortality in elderly males, additional testing for gonadal function and treatment with T may be merited.

The Safety and Effect of Early Mobilization in the Intensive Care Unit According to Cancellation Criteria

Objective:

The aim of this study was to investigate the effect and risk management of early mobilization in the intensive care unit (ICU) with multidisciplinary collaboration and daily goal planning.

Methods:

Rehabilitation of ICU patients in our hospital between April 1, 2019, and September 30, 2019, was investigated retrospectively. The following factors were evaluated: age and sex of the subjects; diseases; the total number of early mobilization therapy sessions done at a lowered goal level; the clinical course of the step-down sessions; reasons for lowering goal levels that corresponded to the cancellation criteria from the officially issued guidelines of the Japanese Association of Rehabilitation Medicine, the expert consensus on ICU, or other reasons for step down; and the rate of planned goals that were achieved.

Results:

Of the 1908 overall rehabilitation sessions carried out during the period of investigation, 9.6% had the planned level lowered; changes in vital signs accounted for 54.6% of the reasons for lowering the level. Of the step-down sessions, 92.3% corresponded with the cancellation criteria of rehabilitation. Early mobilization in the ICU in accordance with daily goal planning via collaboration within the multidisciplinary team during rounds was accomplished in 90.4% of sessions. No serious mobilization-related adverse events were noted during the study period.

Conclusion:

Early mobilization should be performed with daily goal planning by a multidisciplinary team during rounds and should be governed by the cancellation criteria of rehabilitation.

The association between the route of nutrition and serum levels of adipokines in critical illness: a pilot study

Background/aim

Adipokines play an important role in the regulation of metabolism. In critical illness, they alter serum levels and are suspected to worsen clinical outcomes. But the effect of the route of nutrition on adipokines is not known. The purpose of this study was to evaluate the association between the route of nutrition and adipokine levels in critically ill patients.

Materials and methods

This prospective study was performed in an intensive care unit (ICU). Patients admitted to the ICU for least 72 h and receiving either enteral nutrition (EN) via tube feeding or parenteral nutrition (PN) were enrolled. Serum was obtained at baseline, 24 h, and 72 h for concentrations of leptin, adiponectin, resistin, glucagon–like peptide 1 (GLP–1), insulin–like growth factors 1 (IGF–1), and ghrelin.

Results

A total of 26 patients were included in the study. Thirteen patients received EN and 13 patients received PN. In the PN group, leptin level significantly increased (P = 0.037), adiponectin and ghrelin significantly decreased during follow up (P = 0.037, P = 0.008, respectively). There was no significant change between all adipokines in the EN group and resistin, IGF–1 and GLP–1 in the PN group during follow up. Resistin levels were markedly lower in the EN group at both 24 h (P = 0.015) and 72 h (P = 0.006) while GLP–1 levels were higher in the EN group at baseline, 24 h, and 72 h (P = 0.018, P = 0.005, and P = 0.003, respectively). There were no differences in leptin, adiponectin, IGF–1, and ghrelin levels over time.

Conclusion

The delivery of EN in critical illness was associated with decreased resistin levels and increased GLP–1 levels. Thus, the route of nutrition may impact the clinical outcome in critical illness due to adipokines.

Review: Insulin resistance and mitochondrial dysfunction following severe burn injury

The insulin signaling pathway plays a pivotal role in glucose metabolism and metabolic homeostasis. Disruption of this pathway is commonly seen in critical illness such as following severe burn injuries where homeostatic control is lost, leading to "insulin resistance" with poor blood glucose control. The aberrant signaling pathways involved in insulin resistance following burn injury include increases in hyperglycemic stress hormones, pro-inflammatory cytokines and free radical production. Leakage of mitochondrial sequestered self-antigens and signaling between mitochondria and endoplasmic reticulum also contribute to insulin resistance. Greater understanding of molecular processes involved in burn-related insulin resistance could potentially lead to the development of novel therapeutic approaches to improve patient management.

Anabolic and anticatabolic agents used in burn care: What is known and what is yet to be learned

Major thermal injury induces profound metabolic derangements secondary to an inflammatory "stress-induced" hormonal environment. Several pharmacological interventions have been tested in an effort to halt the hypermetabolic response to severe burns. Insulin, insulin growth factor 1, insulin growth factor binding protein 3, metformin, human growth hormone, thyroid hormones, testosterone, oxandrolone, and propranolol, among others, have been proposed to have anabolic or anticatabolic effects. The aim of this broad analysis of pharmacological interventions was to raise awareness of treatment options and to help establishing directions for future clinical research efforts. A PubMed search was conducted on the anabolic and anticatabolic agents used in burn care. One hundred and thirty-five human studies published between 1999 and 2017 were included in this review. The pharmacological properties, rationale for the treatments, efficacy considerations and side effect profiles are summarized in the article. Many of the drugs tested for investigational purposes in the severely thermally injured are not yet gold-standard therapies in spite of their potential benefit. Propranolol and oxandrolone have shown great promise but further evidence is still needed to clarify their potential use for anabolic and anticatabolic purposes.

Nutrition therapy and critical illness: practical guidance for the ICU, post-ICU, and long-term convalescence phases

BACKGROUND

Although mortality due to critical illness has fallen over decades, the number of patients with long-term functional disabilities has increased, leading to impaired quality of life and significant healthcare costs. As an essential part of the multimodal interventions available to improve outcome of critical illness, optimal nutrition therapy should be provided during critical illness, after ICU discharge, and following hospital discharge.

METHODS

This narrative review summarizes the latest scientific insights and guidelines on ICU nutrition delivery. Practical guidance is given to provide optimal nutrition therapy during the three phases of the patient journey.

RESULTS

Based on recent literature and guidelines, gradual progression to caloric and protein targets during the initial phase of ICU stay is recommended. After this phase, full caloric dose can be provided, preferably based on indirect calorimetry. Phosphate should be monitored to detect refeeding hypophosphatemia, and when occurring, caloric restriction should be instituted. For proteins, at least 1.3 g of proteins/kg/day should be targeted after the initial phase. During the chronic ICU phase, and after ICU discharge, higher protein/caloric targets should be provided preferably combined with exercise. After ICU discharge, achieving protein targets is more difficult than reaching caloric goals, in particular after removal of the feeding tube. After hospital discharge, probably very high-dose protein and calorie feeding for prolonged duration is necessary to optimize the outcome. High-protein oral nutrition supplements are likely essential in this period. Several pharmacological options are available to combine with nutrition therapy to enhance the anabolic response and stimulate muscle protein synthesis.

CONCLUSIONS

During and after ICU care, optimal nutrition therapy is essential to improve the long-term outcome to reduce the likelihood of the patient to becoming a "victim" of critical illness. Frequently, nutrition targets are not achieved in any phase of recovery. Personalized nutrition therapy, while respecting different targets during the phases of the patient journey after critical illness, should be prescribed and monitored.

Post-intensive care syndrome: its pathophysiology, prevention, and future directions

Expanding elderly populations are a major social challenge in advanced countries worldwide and have led to a rapid increase in the number of elderly patients in intensive care units (ICUs). Innovative advances in medical technology have enabled lifesaving of patients in ICUs, but there remain various problems to improve their long-term prognoses. Post-intensive care syndrome (PICS) refers to physical, cognition, and mental impairments that occur during ICU stay, after ICU discharge or hospital discharge, as well as the long-term prognosis of ICU patients. Its concept also applies to pediatric patients (PICS-p) and the mental status of their family (PICS-F). Intensive care unit-acquired weakness, a syndrome characterized by acute symmetrical limb muscle weakness after ICU admission, belongs to physical impairments in three domains of PICS. Prevention of PICS requires performance of the ABCDEFGH bundle, which incorporates the prevention of delirium, early rehabilitation, family intervention, and follow-up from the time of ICU admission to the time of discharge. Diary, nutrition, nursing care, and environmental management for healing are also important in the prevention of PICS. This review outlines the pathophysiology, prevention, and future directions of PICS.

Burns in Children

Children have a great deal to gain from recent and future advances in burn care. A very broad range of realized and potential developments are involved. These will be very briefly reviewed within the context of four areas: 1) early evaluation and care issues, 2) acute surgical and critical care issues, 3) rehabilitation and reconstruction issues, and 4) organizational and outcomes issues.

Tailoring nutrition therapy to illness and recovery

Without doubt, in medicine as in life, one size does not fit all. We do not administer the same drug or dose to every patient at all times, so why then would we live under the illusion that we should give the same nutrition at all times in the continuum of critical illness? We have long lived under the assumption that critical illness and trauma lead to a consistent early increase in metabolic/caloric need, the so-called “hypermetabolism” of critical illness. What if this is incorrect? Recent data indicate that early underfeeding of calories (trophic feeding) may have benefits and may require consideration in well-nourished patients. However, we must confront the reality that currently ICU nutrition delivery worldwide is actually leading to “starvation” of our patients and is likely a major contributor to poor long-term quality of life outcomes. To begin to ascertain the actual calorie and protein delivery required for optimal ICU recovery, an understanding of “starvation” and recovery from starvation and lean body mass (LBM) loss is needed. To begin to answer this question, we must look to the landmark Minnesota Starvation Study from 1945. This trial defines much of the world’s knowledge about starvation, and most importantly what is required for recovery from starvation and massive LBM loss as occurs in the ICU. Recent and historic data indicate that critical illness is characterized by early massive catabolism, LBM loss, and escalating hypermetabolism that can persist for months or years. Early enteral nutrition during the acute phase should attempt to correct micronutrient/vitamin deficiencies, deliver adequate protein, and moderate nonprotein calories in well-nourished patients, as in the acute phase they are capable of generating significant endogenous energy. Post resuscitation, increasing protein (1.5–2.0 g/kg/day) and calories are needed to attenuate LBM loss and promote recovery. Malnutrition screening is essential and parenteral nutrition can be safely added following resuscitation when enteral nutrition is failing based on pre-illness malnutrition and LBM status. Following the ICU stay, significant protein/calorie delivery for months or years is required to facilitate functional and LBM recovery, with high-protein oral supplements being essential to achieve adequate nutrition.

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

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. Furthermore, 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. 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/anticatabolic 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 computerized tomography scan and ultrasound analysis of LBM 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-feeding 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 to target preoperative 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.

Nutrition Therapy in Sepsis

Sepsis is characterized by early massive catabolism, lean body mass (LBM) loss, and escalating hypermetabolism persisting for months to years. Early enteral nutrition should attempt to correct micronutrient/vitamin deficiencies, deliver adequate protein and moderated nonprotein calories, as well-nourished patients can generate reasonable endogenous energy. After resuscitation, increasing protein/calories are needed to attenuate LBM loss and promote recovery. Malnutrition screening is essential, and parenteral nutrition can be safely added when enteral nutrition is failing based on preillness malnutrition. Following discharge from intensive care unit, significantly increased protein/calorie delivery is required for months to years to facilitate functional and LBM recovery.

The biochemical alterations underlying post-burn hypermetabolism

A severe burn can trigger a hypermetabolic state which lasts for years following the injury, to the detriment of the patient. The drastic increase in metabolic demands during this phase renders it difficult to meet the body's nutritional requirements, thus increasing muscle, bone and adipose catabolism and predisposing the patient to a host of disorders such as multi-organ dysfunction and sepsis, or even death. Despite advances in burn care over the last 50 years, due to the multifactorial nature of the hypermetabolic phenomenon it is difficult if not impossible to precisely identify and pharmacologically modulate the biological mediators contributing to this substantial metabolic derangement. Here, we discuss biomarkers and molecules which play a role in the induction and mediation of the hypercatabolic condition post-thermal injury. Furthermore, this thorough review covers the development of the factors released after burns, how they induce cellular and metabolic dysfunction, and how these factors can be targeted for therapeutic interventions to restore a more physiological metabolic phenotype after severe thermal injuries. This article is part of a Special Issue entitled: Immune and Metabolic Alterations in Trauma and Sepsis edited by Dr. Raghavan Raju.

Update on metabolism and nutrition therapy in critically ill burn patients

Major burn injury triggers severe oxidative stress, a systemic inflammatory response, and a persistent hypermetabolic and hypercatabolic state with secondary sarcopenia, multiorgan dysfunction, sepsis and an increased mortality risk. Calorie deficit, negative protein balance and antioxidant micronutrient deficiency after thermal injury have been associated to poor clinical outcomes. In this context, personalized nutrition therapy with early enteral feeding from the start of resuscitation are indicated. Over the last four decades, different nutritional and pharmacological interventions aimed at modulating the immune and metabolic responses have been evaluated. These strategies have been shown to be able to minimize acute malnutrition, as well as modulate the immunoinflammatory response, and improve relevant clinical outcomes in this patient population. The purpose of this updating review is to summarize the most current evidence on metabolic response and nutrition therapy in critically ill burn patients.

What factors influence protein synthesis and degradation in critical illness?

PURPOSE OF REVIEW

The optimal approach to improve protein metabolism in critical illness is not yet fully defined. Here, we have summarized recent literature dealing with the main catabolic and anabolic factors influencing protein kinetics in acute hypercatabolic patients.

RECENT FINDINGS

Protein/amino acid intake levels should be adapted to type and severity of illness, keeping in mind that energy overfeeding is associated with poor outcome. A number of anticatabolic nutraceuticals and drugs have been tested in acute patients. The encouraging results have been obtained with β-hydroxy-β-methylbutyrate, omega-3 fatty acids, oxandrolone, propranolol, and metformin. Their efficacy and lack of side-effects need to be confirmed. Physical therapy, including muscle electro-stimulation, appears a very promising intervention, both effective and safe.

SUMMARY

Protein catabolism can be minimized in acute patients by adequate nutritional support, early mobilization, and, possibly, pharmacological and nutraceutical interventions. A combination of these strategies should be tested in randomized controlled trials.