Metabolic support of the obese intensive care unit patient: a current perspective

Navigating Nutritional Strategies: Permissive Underfeeding in Critically Ill Patients

Nutritional support is a critical component of care for critically ill patients, impacting their recovery and overall prognosis. Traditional approaches to feeding in the intensive care unit (ICU) have focused on meeting estimated energy requirements, often resulting in unintended consequences such as overfeeding and associated complications. Permissive underfeeding, a concept gaining attention recently, offers a more controlled approach by intentionally providing fewer calories than traditionally recommended. This comprehensive review explores the rationale, evidence, and practical considerations surrounding permissive underfeeding in critically ill patients. We discuss the physiological basis of permissive underfeeding, its potential benefits in mitigating the risks of overfeeding, and the challenges associated with implementation in clinical practice. Through an analysis of critical studies and clinical trials, we evaluate the comparative effectiveness of permissive underfeeding versus traditional feeding methods and examine its impact on patient outcomes. Recommendations for patient selection, monitoring, and future research directions are provided to guide clinicians in optimizing nutritional support strategies for critically ill individuals. By considering the role of permissive underfeeding alongside traditional feeding approaches, healthcare professionals can tailor nutritional interventions to individual patient needs, ultimately improving outcomes in the ICU.

Nutritional approach for increasing public health during pandemic of COVID-19: A comprehensive review of antiviral nutrients and nutraceuticals

Background: The novel coronavirus (COVID-19) is considered as the most life-threatening pandemic disease during the last decade. The individual nutritional status, though usually ignored in the management of COVID-19, plays a critical role in the immune function and pathogenesis of infection. Accordingly, the present review article aimed to report the effects of nutrients and nutraceuticals on respiratory viral infections including COVID-19, with a focus on their mechanisms of action. Methods: Studies were identified via systematic searches of the databases including PubMed/ MEDLINE, ScienceDirect, Scopus, and Google Scholar from 2000 until April 2020, using keywords. All relevant clinical and experimental studies published in English were included. Results: Protein-energy malnutrition (PEM) is common in severe respiratory infections and should be considered in the management of COVID-19 patients. On the other hand, obesity can be accompanied by decreasing the host immunity. Therefore, increasing physical activity at home and a slight caloric restriction with adequate intake of micronutrients and nutraceuticals are simple aids to boost host immunity and decrease the clinical manifestations of COVID-19. Conclusion: The most important nutrients which can be considered for COVID-19 management are vitamin D, vitamin C, vitamin A, folate, zinc, and probiotics. Their adequacy should be provided through dietary intake or appropriate supplementation. Moreover, adequate intake of some other dietary agents including vitamin E, magnesium, selenium, alpha linolenic acid and phytochemicals are required to maintain the host immunity.

Nitrogen balance in mechanically ventilated obese patients

ABSTRACT Objective This study aimed to evaluate if the protein intake recommendations for obese critically ill requiring mechanical ventilation are sufficient to promote a positive or neutral nitrogen balance. Methods Cross-sectional study that included 25 obese, ≥18 years old, undergoing mechanical ventilation and who were target to receive high-protein enteral nutrition therapy (2.0-2.5g/kg ideal body weight). Clinical, nutritional and biochemical variables were analyzed. Nitrogen balance was performed when patient was receiving full enteral nutrition therapy and was classified: positive when intake was greater than excretion; negative when excretion was greater than intake; neutral when both were equal. Results The characteristics of patients evaluated were 64.1±9.4 years old, clinical treatment 88%, body mass index 36.5±5.1kg/m2, nitrogen balance 0.3g/day (-5.3 to 4.8g/day), protein intake 2.1g/day (2.0-2.3g/kg) ideal body weight. Of individuals analyzed, 52% showed positive or neutral nitrogen balance with median of 4.23g/day 2.41 to 6.40g/day) in comparison to negative group with median of -5.27g/day (-10.38 to -3.86g/day). Adults had higher ratio of negative nitrogen balance (57.1%) than elderly (44.4%), with protein intake of 2.0 versus 2.1g/day, respectively. No correlation was found between nitrogen balance and variables assessed. Conclusion High-protein enteral nutrition therapy contributed to positive or neutral nitrogen balance for approximately half of obese ventilated individuals. With similar protein intake, elderly showed a higher proportion of positive or neutral nitrogen balance. Nitrogen balance can be influenced by various factors, so further studies are required to identify different protein needs in obese critically.

The Influence of Obesity on Treatment and Outcome of Severely Burned Patients

Obesity and the related medical, social, and economic impacts are relevant multifactorial and chronic conditions that also have a meaningful impact on outcomes following a severe injury, including burns. In addition to burn-specific difficulties, such as adequate hypermetabolic response, fluid resuscitation, and early wound coverage, obese patients also present with common comorbidities, such as arterial hypertension, diabetes mellitus, or nonalcoholic fatty liver disease. In addition, the pathophysiologic response to severe burns can be enhanced. Besides the increased morbidity and mortality compared to burn patients with normal weight, obese patients present a challenge in fluid resuscitation, perioperative management, and difficulties in wound healing. The present work is an in-depth review of the current understanding of the influence of obesity on the management and outcome of severe burns.

Impact of Obesity and Visceral Fat on Mortality in Hematopoietic Stem Cell Transplantation

RATIONALE

Many studies have shown the importance of body composition parameters, muscle, and fat mass, evaluated by several methods in hematopoietic stem cell transplantation (HSCT) outcomes. Ultrasound (US) is an efficient and low-cost method to evaluate body composition, even though there have not been many studies in HSCT.

OBJECTIVES

Our goal was to investigate the muscle, visceral fat (VF), and echogenicity before HSCT and after engraftment, evaluated by US and its association with outcomes.

METHODS

All adult patients with hematological malignances admitted for HSCT autologous and allogeneic were eligible to enter this prospective study. Their thigh muscle thickness, VF, and echogenicity were evaluated by US on the first day of hospitalization (baseline) and after engraftment (15-25 days post-HSCT).

RESULTS

We evaluated 50 patients; 42% were male and 58% had undergone allogeneic HSCT. Most patients were <55 years old (68%) and had normal body mass index (50%). We found a significant reduction of right and left muscle thickness (P < .001) and echogenicity (P = .002) after engraftment compared with baseline. Our elderly patients had significantly bigger right-thigh muscle thickness (P = .02) and more VF (P = .009). The following data were higher in obese patients: right and left muscle thickness (P < .001), VF (P = .003), and echogenicity (P = .04). Death in the first 100 days had a positive association with obesity (P = 0.001) and VF (P = .002). VF was the only variable independent of HSCT type and age in mortality risk.

CONCLUSION

Obesity and VF had an important impact in mortality. US could be a useful tool and strategy for evaluating body composition in HSCT patients.

Associations between body mass index and mortality in acute-on-chronic liver failure patients

INTRODUCTION AND OBJECTIVES

The association between the level of body mass index (BMI) and the mortality of patients with critical liver disease remains unclear. This study aimed to examine the association between BMI and hospital mortality of patients with acute-on-chronic liver failure (ACLF).

METHODS

Clinical data from 146 ACLF patients were collected and analyzed. BMI was categorized into three groups: lower BMI (<18.5kg/m²), normal BMI (18.5-24.9kg/m²), and overweight (25.0-32.0kg/m²). BMI and laboratory parameters were measured one day before, or on the day of the start of the treatment. Values of BMI and laboratory parameters were compared between survivors and non-survivors, and then hospital mortality rates were compared among patients with different BMI levels.

RESULTS

The prognosis of ACLF patients was significantly correlated with international normalized ratio (INR), albumin and BMI. The ACLF patients with low albumin level and high INR values tend to have a high mortality rate. Also, survival time was significantly shorter in the ACLF patients with lower BMI, while patients with normal and overweight values had longer survival time.

CONCLUSIONS

A graded association between BMI and hospital mortality with a strong significant trend was found in ACLF patients in China.

Nutritional Support in Coronavirus 2019 Disease

The epidemic that broke out in Chinese Wuhan at the beginning of 2020 presented how important the rapid diagnosis of malnutrition (elevating during intensive care unit stay) and the immediate implementation of caloric and protein-balanced nutrition care are. According to specialists from the Chinese Medical Association for Parenteral and Enteral Nutrition (CSPEN), these activities are crucial for both the therapy success and reduction of mortality rates. The Chinese have published their recommendations including principles for the diagnosis of nutritional status along with the optimal method for nutrition supply including guidelines when to introduce education approach, oral nutritional supplement, tube feeding, and parenteral nutrition. They also calculated energy demand and gave their opinion on proper monitoring and supplementation of immuno-nutrients, fluids and macronutrients intake. The present review summarizes Chinese observations and compares these with the latest European Society for Clinical Nutrition and Metabolism guidelines. Nutritional approach should be an inseparable element of therapy in patients with COVID-19.

Causes of nasoenteral tube obstruction in tertiary hospital patients

BACKGROUND/OBJECTIVES

Obstruction of the nasoenteral tube is one of the complications of enteral nutrition therapy, and its causes and frequency of occurrence are not well understood. To evaluate the causes of enteral nutrition feeding tube obstruction. To study the time elapsed between the beginning of the nutrition therapy and the obstruction of the tube.

SUBJECTS/METHODS

This was a retrospective cohort study of 1170 patients aged 18 years or older who were hospitalized at Sírio-Libanês Hospital between January 2015 and October 2017, and who were undergoing enteral nutrition therapy delivered using an infusion pump through a nasogastric or nasoenteral tube. The study population included 683 (58%) men and 487 (42%) women. The median age was 79 years. Of these, 1084 patients received enteral nutrition and medication through the feeding tube, and 86 received medication alone. Variables investigated as causes of feeding tube obstruction were the administration of medication through the tube, type of diet, and use of symbiotics.

RESULTS

Obstruction rates were 4% for up to 40 days of observation and 8% for the total observation time. The time for obstruction of 10% of the tubes in patients receiving rivaroxaban, linagliptin, metformin, and nystatin was 16, 19, 20, and 28 days, respectively.

CONCLUSIONS

The main cause of nasoenteral tube obstruction (odds ratio) was the combination of metformin (2.0), nystatin (3.1), linagliptin (4.3), rivaroxaban (2.4), and a high-protein diet (1.9). Overall, proper tube care and strict compliance with tubal drug delivery guidelines can result in low tube obstruction rates.

Addition of blood flow restriction to passive mobilization reduces the rate of muscle wasting in elderly patients in the intensive care unit: a within-patient randomized trial

OBJECTIVE:

To evaluate the addition of blood flow restriction to passive mobilization in patients in the intensive care unit.

DESIGN:

The study was a within-patient randomized trial.

SETTING:

Two intensive care units in Belém, from September to October 2017.

SUBJECTS:

In total, 34 coma patients admitted to the intensive care unit sector, and 20 patients fulfilled the study requirements.

INTERVENTIONS:

All participants received the passive mobilization protocol for lower limbs, and blood flow restriction was added only for one side in a concurrent fashion. Intervention lasted the entire patient's hospitalization time.

MAIN OUTCOME MEASUREMENT:

Thigh muscle thickness and circumference.

RESULTS:

In total, 34 subjects were enrolled in the study: 11 were excluded for exclusion criteria, 3 for death, and 20 completed the intervention (17 men and 3 women; mean age: 66 ± 4.3 years). Despite both groups presented atrophy, the atrophy rate was lower in blood flow restriction limb in relation to the control limb (-2.1 vs. -2.8 mm, respectively, in muscle thickness; P = 0.001). In addition, the blood flow restriction limb also had a smaller reduction in the thigh circumference than the control limb (-2.5 vs. -3.6 cm, respectively; P = 0.001).

CONCLUSION:

The use of blood flow restriction did not present adverse effects and seems to be a valid strategy to reduce the magnitude of the rate of muscle wasting that occurs in intensive care unit patients.

Feeding the critically ill obese patient: a systematic review protocol

REVIEW QUESTION/OBJECTIVE

The objective of this review is to identify effective enteral nutritional regimens targeting protein and calorie delivery for the critically ill obese patient on morbidity and mortality.More specifically, the review question is:In the critically ill obese patient, what is the optimal enteral protein and calorie target that improves mortality and morbidity?

BACKGROUND

The World Health Organization (WHO) defines obesity as abnormal or excessive fat accumulation that may impair health, or, empirically, as a body mass index (BMI) ≥ 30 kg/m. Twenty-eight percent of the Australian population is obese with the prevalence rising to 44% in rural areas, and there is evidence that rates of obesity are increasing. The prevalence of obese patients in intensive care largely mirrors that of the general population. There is concern, however, that this may also be rising. A recently published multi-center nutritional study of critically ill patients reported a mean BMI of 29 in their sample, suggesting that just under 50% of their intensive care population is obese. It is inevitable, therefore, that the intensivist will care for the critically ill obese patient.Managing the critically ill obese patient is challenging, not least due to the co-morbid diseases frequently associated with obesity, including diabetes mellitus, cardiovascular disease, dyslipidaemia, sleep disordered breathing and respiratory insufficiency, hepatic steatohepatitis, chronic kidney disease and hypertension. There is also evidence that metabolic processes differ in the obese patient, particularly those with underlying insulin resistance, itself a marker of the metabolic syndrome, which may predispose to futile cycling, altered fuel utilization and protein catabolism. These issues are compounded by altered drug pharmacokinetics, and the additional logistical issues associated with prophylactic, therapeutic and diagnostic interventions.It is entirely plausible that the altered metabolic processes observed in the obese intensify and compound the metabolic changes that occur during critical illness. The early phases of critical illness are characterized by an increase in energy expenditure, resulting in a catabolic state driven by the stress response. Activation of the stress response involves up-regulation of the sympathetic nervous system and the release of pituitary hormones resulting in altered cortisol metabolism and elevated levels of endogenous catecholamines. These produce a range of metabolic disturbances including stress hyperglycemia, arising from both peripheral resistance to the effects of anabolic factors (predominantly insulin) and increased hepatic gluconeogenesis. Proteolysis is accelerated, releasing amino acids that are thought to be important in supporting tissue repair, immune defense and the synthesis of acute phase reactants. There is also altered mobilization of fuel stores, futile cycling, and evidence of altered lipoprotein metabolism. In the short term this is likely to be an adaptive response, but with time and ongoing inflammation this becomes maladaptive with a concomitant risk of protein-calorie malnutrition, immunosuppression and wasting of functional muscle tissue resulting from protein catabolism, and this is further compounded by disuse atrophy. Muscle atrophy and intensive care unit (ICU) acquired weakness is complex and poorly understood, but it is postulated that the provision of calories and sufficient protein to avoid a negative nitrogen balance mitigates this process. Avoiding lean muscle mass loss in the obese intuitively has substantial implications, given the larger mass that is required to be mobilized during their rehabilitation phase.There is, in addition, evolving evidence that hormones derived from both the gut and adipose tissue are also involved in the response to stress and critical illness, and that adipose tissue in particular is not a benign tissue bed, but rather should be considered an endocrine organ. Some of these hormones are thought to be pro-inflammatory and some anti-inflammatory; however both the net result and clinical significance of these are yet to be fully elucidated.The provision of adequate nutrition has become an integral component of supportive ICU care, but is complex. There is ongoing debate within critical care literature regarding the optimal route of delivery, the target dose, and the macronutrient components (proportion of protein and non-protein calories) of nutritional support. A number of studies have associated caloric deficit with morbidity and mortality, with the resultant assumption that prescribing sufficient calories to match energy expenditure will reduce morbidity and mortality, although the evidence base underpinning this assumption is limited to observational studies and small, randomized trials.There is research available that suggests hyper-caloric feeding or hyper-alimentation, particularly of carbohydrates, may result in increased morbidity including hyperglycemia, liver steatosis, respiratory insufficiency with prolonged duration of mechanical ventilation, re-feeding syndrome and immune suppression. But the results from studies of hypo-caloric and eucaloric feeding regimens in critically ill patients are conflicting, independent of the added metabolic complexities observed in the critically ill obese patient.Notwithstanding the debate regarding the dose and components of nutritional therapy, there is consensus that nutrition should be provided, preferably via the enteral route, and preferably initiated early in the ICU admission. The enteral route is preferred for a variety of reasons, not the least of which is cost. In addition there is evidence to suggest the enteral route is associated with the maintenance of gut integrity, a reduction in bacterial translocation and infection rates, a reduction in the incidence of stress ulceration, attenuation of oxidative stress, release of incretins and other entero-hormones, and modulation of systemic immune responses. Yet there is evidence that the initiation of enteral nutritional support for the obese critically ill patient is delayed, and that when delivered is at sub-optimal levels. The reasons for this remain obscure, but may be associated with the false assumption that every obese patient has nutritional reserves due to their adipose tissues, and can therefore withstand longer periods with no, or reduced nutritional support. In fact obesity does not necessarily protect from malnutrition, particularly protein and micronutrient malnutrition. It has been suggested by some authors that the malnutrition status of critically ill patients is a stronger predictor of mortality than BMI, and that once malnutrition status is controlled for, the apparent protective effects of obesity observed in several epidemiological studies dissipate. This would be consistent with the large body of evidence that associates malnutrition (BMI < 20 kg/m) with increased mortality, and has led some authors to postulate that the weight-mortality relationship is U-shaped. This has proven difficult to demonstrate, however, due to recognized confounding influences such as chronic co-morbidities, baseline nutritional status and the nature of the presenting critical illness.This has led to interest in nutritional regimens targeting alternative calorie and protein goals to protect the obese critically ill patient from complications arising from critical illness, and particularly protein catabolism. However, of the three major nutritional organizations, the American Society of Parenteral and Enteral Nutrition (ASPEN) is the only professional organization to make specific recommendations about providing enteral nutritional support to the critically ill obese patient, recommending a regimen targeting a hypo-caloric, high-protein goal. It is thought that this regimen, in which 60-70% of caloric requirements are provided promotes steady weight loss, while providing sufficient protein to achieve a neutral, or slightly positive, nitrogen balance, mitigating lean muscle mass loss, and allowing for wound healing. Targeting weight loss is proposed to improve insulin sensitivity, improve nursing care and reduce the risk of co-morbidities, although how this occurs and whether it can occur over the relatively short time frame of an intensive care admission (days to weeks) remains unclear. Despite these recommendations observational data of international nutritional practice suggest that ICU patients are fed uniformly low levels of calories and protein across BMI groups.Supporting the critically ill obese patient will become an increasingly important skill in the intensivist's armamentarium, and enteral nutritional therapy forms a cornerstone of this support. Yet, neither the optimal total caloric goal nor the macronutrient components of a feeding regimen for the critically ill obese patient is evident. Although the suggestion that altering the macronutrient goals for this vulnerable group of patients appears to have a sound physiological basis, the level of evidence supporting this remains unclear, and there are no systematic reviews on this topic. The aim of this systematic review is to evaluate existing literature to determine the best available evidence describing a nutritional strategy that targets energy and protein delivery to reduce morbidity and mortality for the obese patient who is critically ill.

Evaluation of factors influencing 18F-FET uptake in the brain

PET using the amino-acid O-(2-¹⁸F-fluoroethyl)-l-tyrosine (¹⁸F-FET) is gaining increasing interest for brain tumour management. Semi-quantitative analysis of tracer uptake in brain tumours is based on the standardized uptake value (SUV) and the tumour-to-brain ratio (TBR). The aim of this study was to explore physiological factors that might influence the relationship of SUV of ¹⁸F-FET uptake in various brain areas, and thus affect quantification of ¹⁸F-FET uptake in brain tumours. Negative ¹⁸F-FET PET scans of 107 subjects, showing an inconspicuous brain distribution of ¹⁸F-FET, were evaluated retrospectively. Whole-brain quantitative analysis with Statistical Parametric Mapping (SPM) using parametric SUV PET images, and volumes of interest (VOIs) analysis with fronto-parietal, temporal, occipital, and cerebellar SUV background areas were performed to study the effect of age, gender, height, weight, injected activity, body mass index (BMI), and body surface area (BSA). After multivariate analysis, female gender and high BMI were found to be two independent factors associated with increased SUV of ¹⁸F-FET uptake in the brain. In women, SUV_mean of ¹⁸F-FET uptake in the brain was 23% higher than in men (p < 0.01). SUV_mean of ¹⁸F-FET uptake in the brain was positively correlated with BMI (r = 0.29; p < 0.01). The influence of these factors on SUV of ¹⁸F-FET was similar in all brain areas. In conclusion, SUV of ¹⁸F-FET in the normal brain is influenced by gender and weakly by BMI, but changes are similar in all brain areas.

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SUV_mean of ¹⁸F-FET in the normal brain is influenced by gender.

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SUV_mean of ¹⁸F-FET in the normal brain is weekly influenced by BMI.

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The influence of these factors on SUV of ¹⁸F-FET is similar in all brain areas.

Considerations When Using Predictive Equations to Estimate Energy Needs Among Older, Hospitalized Patients: A Narrative Review

The aim of this narrative review was to summarize the accuracy of predictive equations used to estimate energy expenditure in older, hospitalized adults. More than 50% of patients admitted to intensive care units are older adults. Currently accepted prediction equations used to determine energy intake in the older, hospitalized patient were not specifically developed for the aging population. Rates of multimorbidity, polypharmacy and malnutrition, conditions that influence energy expenditure, are higher in older adults compared to younger adults. For these reasons, current equations may not accurately assess energy needs in this population. As the evidence demonstrating the importance of nutritional supplementation in older, hospitalized adults grows, more accurate energy assessment methods that account for age-related conditions are needed to predict nutritional requirements.

New Guidelines for Assessment of Malnutrition in Adults: Obese Critically Ill Patients

Recently released recommendations for detection and documentation of malnutrition in adults in clinical practice define 3 types of malnutrition: starvation related, acute disease or injury related, and chronic disease related. The first 2 are more easily recognized, but the third may be more often unnoticed, particularly in obese patients. Critical care patients tend to be at high risk for malnutrition and thus require a thorough nutritional assessment. Compared with patients of earlier times, intensive care unit patients today tend to be older, have more complex medical and comorbid conditions, and often are obese. Missed or delayed detection of malnutrition in these patients may contribute to increases in hospital morbidity and longer hospital stays. Critical care nurses are in a prime position to screen patients at risk for malnutrition and to work with members of the interprofessional team in implementing nutritional intervention plans.

ACG Clinical Guideline: Nutrition Therapy in the Adult Hospitalized Patient

The value of nutrition therapy for the adult hospitalized patient is derived from the outcome benefits achieved by the delivery of early enteral feeding. Nutritional assessment should identify those patients at high nutritional risk, determined by both disease severity and nutritional status. For such patients if they are unable to maintain volitional intake, enteral access should be attained and enteral nutrition (EN) initiated within 24-48 h of admission. Orogastric or nasogastric feeding is most appropriate when starting EN, switching to post-pyloric or deep jejunal feeding only in those patients who are intolerant of gastric feeds or at high risk for aspiration. Percutaneous access should be used for those patients anticipated to require EN for >4 weeks. Patients receiving EN should be monitored for risk of aspiration, tolerance, and adequacy of feeding (determined by percent of goal calories and protein delivered). Intentional permissive underfeeding (and even trophic feeding) is appropriate temporarily for certain subsets of hospitalized patients. Although a standard polymeric formula should be used routinely in most patients, an immune-modulating formula (with arginine and fish oil) should be reserved for patients who have had major surgery in a surgical ICU setting. Adequacy of nutrition therapy is enhanced by establishing nurse-driven enteral feeding protocols, increasing delivery by volume-based or top-down feeding strategies, minimizing interruptions, and eliminating the practice of gastric residual volumes. Parenteral nutrition should be used in patients at high nutritional risk when EN is not feasible or after the first week of hospitalization if EN is not sufficient. Because of their knowledge base and skill set, the gastroenterologist endoscopist is an asset to the Nutrition Support Team and should participate in providing optimal nutrition therapy to the hospitalized adult patient.

Clinical Guide for the Use of Metabolic Carts: Indirect Calorimetry--No Longer the Orphan of Energy Estimation

Critically ill patients often require nutrition support, but accurately determining energy needs in these patients is difficult. Energy expenditure is affected by patient characteristics such as weight, height, age, and sex but is also influenced by factors such as body temperature, nutrition support, sepsis, sedation, and therapies. Using predictive equations to estimate energy needs is known to be inaccurate. Therefore, indirect calorimetry measurement is considered the gold standard to evaluate energy needs in clinical practice. This review defines the indications, limitations, and pitfalls of this technique and gives practice suggestions in various clinical situations.

Validation Study of Energy Requirements in Critically Ill, Obese Cancer Patients

BACKGROUND

Current guidelines from the American Society for Parenteral and Enteral Nutrition and the Society of Critical Care Medicine (ASPEN/SCCM) regarding caloric requirements and the provision of nutrition support in critically ill, obese adults may not be suitable for similar patients with cancer. We sought to determine whether the current guidelines accurately estimate the energy requirements, as measured by indirect calorimetry (IC), of critically ill, obese cancer patients.

MATERIALS AND METHODS

This was a retrospective validation study of critically ill, obese cancer patients from March 1, 2007, to July 31, 2010. All patients ≥18 years of age with a body mass index (BMI) ≥30 kg/m(2) who underwent IC were included. We compared the measured energy expenditure (MEE) against the upper limit of the recommended guideline (25 kcal/kg of ideal body weight [IBW]) and MEE between medical and surgical patients in the intensive care unit.

RESULTS

Thirty-three patients were included in this study. Mean MEE (28.7 ± 5.2 kcal/kg IBW) was significantly higher than 25 kcal/kg IBW (P < .001), and 78% of patients had nutrition requirements greater than the current guideline recommendations. No significant differences in MEE between medical and surgical patients in the ICU were observed.

CONCLUSIONS

Critically ill, obese cancer patients require more calories than the current guidelines recommend, likely due to malignancy-associated metabolic variations. Our results demonstrate the need for IC studies to determine the energy requirements in these patients and for reassessment of the current recommendations.

Hypocaloric enteral nutrition protects against hypoglycemia associated with intensive insulin therapy better than intravenous dextrose

Intensive insulin therapy treats hyperglycemia but increases the risk of hypoglycemia. Typically, intravenous dextrose is given to prevent hypoglycemia; however, enteral nutrition is preferred. We hypothesized that the provision of hypocaloric enteral nutrition would protect against hypoglycemia. A retrospective analysis was performed evaluating patients treated with intensive insulin therapy comparing the use of enteral nutrition versus a dextrose-only intravenous solution. Nutrition in the 2 hours before each blood glucose test was assessed, and the association with hypoglycemia (50 mg/dL or less) evaluated. Risk of hypoglycemia as a function of nutrition type and rate was estimated by multivariable regression. A total of 26,140 blood glucose tests were collected on 1289 patients. Hypoglycemia occurred in 6.4 per cent of patients. In regression models, enteral nutrition was the strongest protective factor against hypoglycemia (P < 0.001) with the largest risk reduction (steepest portion of the curve) occurring at 60 per cent goal. Hypocaloric enteral nutrition showed a greater risk reduction than a peripheral dextrose-only intravenous solution alone. In the setting of intensive insulin therapy, the provision of enteral nutrition, even if hypocaloric, is sufficient to protect against hypoglycemia. Future prospective studies should evaluate the efficacy of enteral nutrition in reducing the risk of hypoglycemia and whether lower rates of hypoglycemia correspond to improved outcomes.

Hypocaloric Enteral Nutrition Protects against Hypoglycemia Associated with Intensive Insulin Therapy Better than Intravenous Dextrose

Intensive insulin therapy treats hyperglycemia but increases the risk of hypoglycemia. Typically, intravenous dextrose is given to prevent hypoglycemia; however, enteral nutrition is preferred. We hypothesized that the provision of hypocaloric enteral nutrition would protect against hypoglycemia. A retrospective analysis was performed evaluating patients treated with intensive insulin therapy comparing the use of enteral nutrition versus a dextrose-only intravenous solution. Nutrition in the 2 hours before each blood glucose test was assessed, and the association with hypoglycemia (50 mg/dL or less) evaluated. Risk of hypoglycemia as a function of nutrition type and rate was estimated by multivariable regression. A total of 26,140 blood glucose tests were collected on 1289 patients. Hypoglycemia occurred in 6.4 per cent of patients. In regression models, enteral nutrition was the strongest protective factor against hypoglycemia ( P < 0.001) with the largest risk reduction (steepest portion of the curve) occurring at 60 per cent goal. Hypocaloric enteral nutrition showed a greater risk reduction than a peripheral dextrose-only intravenous solution alone. In the setting of intensive insulin therapy, the provision of enteral nutrition, even if hypocaloric, is sufficient to protect against hypoglycemia. Future prospective studies should evaluate the efficacy of enteral nutrition in reducing the risk of hypoglycemia and whether lower rates of hypoglycemia correspond to improved outcomes.

Nutritional care of the obese adult burn patient: a U.K. Survey and literature review

Obesity is an emerging healthcare problem and affects an increasing number of burn patients worldwide. An email survey questionnaire was constructed and distributed among the 16 U.K. burn services providing adult inpatient facilities to investigate nutritional practices in obese thermally injured patients. Responses received from all dieticians invited to participate in the study were analyzed, and a relevant literature review of key aspects of nutritional care is presented. The majority of services believe that obese patients warrant a different nutritional approach with specific emphasis to avoid overfeeding. The most common algebraic formulae used to calculate calorific requirements include the Schofield, Henry, and modified Penn State equations. Indirect calorimetry despite being considered the "criterion standard" tool to calculate energy requirements is not currently used by any of the U.K. burn services. Gastric/enteral nutrition is initiated within 24 hours of admission in the services surveyed, and a variety of different practices were noted in terms of fasting protocols before procedures requiring general anesthesia/sedation. Hypocaloric regimens for obese patients are not supported by the majority of U.K. facilities, given the limited evidence base supporting their use. The results of this survey outline the wide diversity of dietetic practices adopted in the care of obese burn patients and reveal the need for further study to determine optimal nutritional strategies.

Veno-venous extracorporeal membrane oxygenation in obese surgical patients with hypercapnic lung failure

BACKGROUND

In patients with a body mass index (BMI) > 35 kg/m(2) , or in extreme cases weighting > 250 kg, we are faced with special challenges in therapy and logistics. The aim was to analyze the feasibility of the extracorporeal membrane oxygenation (ECMO) in these patients.

METHODS

We report 12 adult patients [10 male, 2 female; mean age 56.7 (34-74) years; mean BMI 47.9 (35-88.6) kg/m(2) ] with acute lung failure treated with veno-venous ECMO from 1 January 2009 to 30 June 2013. All patients were cannulated percutaneously into the right internal jugular vein and one of the femoral veins at the bedside.

RESULTS

The mean time to ECMO after admission to the intensive care unit (ICU) was 2 days (0-10), and the mean ECMO run time was 9 days (4 h-20 days). Lung failure occurred in the contexts of wound infection (two patients), anaphylactic shock (one patient), major trauma (one patients) and pneumonia after surgery (four patients), and respiratory failure in abdominal sepsis (four patients). The mean time in the ICU was 31 days (0-89), and the mean time at the hospital was 38 days (0-101). Three patients died on the system because of multiorgan failure; nine patients were weaned from ECMO (75%); and six were patients discharged from the ICU and from the hospital (survival rate 50%).

CONCLUSIONS

ECMO in obese patients is feasible and life saving. Therefore, a percutaneous cannulation remains feasible. The goals of the ECMO therapy include early spontaneous breathing, tracheotomy, rapid reduction of sedation and adequate analgesia. Rehabilitation includes nutritional therapy, as well as psychiatric therapy and bariatric surgery, as perspectives for the future.

Optimizing energy and protein balance in the ICU

PURPOSE OF REVIEW

Perhaps now more than ever, appropriate nutrition delivery in the ICU is a highly debated issue. Nutrition guidelines for ICU patients by European Society for Clinical Nutrition and Metabolism in Europe, The Canadian Nutrition Guidelines, and American Society for Parenteral and Enteral Nutrition in the USA continue to disagree about the need to feed early and how. Most ICU patients around the world appear to be poorly fed.

RECENT FINDINGS

Most studies have focussed on energy supply by enteral or parenteral nutrition. Some studies suggest that late initiation of energy supply could be beneficial. However, studies still not provide the answer as to when and how to feed the patient. A few studies have now also focussed on protein supply. Studies agree on the importance of adequate protein supply, 1.2-2.0 g/kg, for outcome. In fact, early protein supply might be more important than energy supply; however, limited data are available.

SUMMARY

These findings implicate that optimization of protein balance in ICU patients as well as energy balance will improve outcome. In clinical practice, protein targets for patients should be set and achieved. More research is needed to define when and how to best feed the ICU patient.

Disease-specific nutrition therapy: one size does not fit all

INTRODUCTION

The delivery of adequate nutrition is an integral part of the care of the critically ill surgical patient, and the provision of nutrition may have a greater impact on outcome than many other therapies commonly employed in the treatment of certain disease states.

METHODS

A review of the existing literature was performed to summarize the evidence for utilizing disease-specific nutrition in critically ill surgical patients.

RESULTS

Enteral nutrition, unless specifically contraindicated, is always preferable to parenteral nutrition. Methodological heterogeneity and conflicting results plague research in immunonutrition, and routine use is not currently recommended in critically ill patients.

CONCLUSION

There is currently insufficient evidence to recommend the routine initial use of most disease-specific formulas, as most patients with the disease in question will tolerate standard enteral formulas. However, the clinician should closely monitor for signs of intolerance and utilize disease-specific formulas when appropriate.

Nutrition in the critically-ill obese patient

People are fatter than they used to be. Although the upward trend has slowed in recent years, more than one third of all adults in the US are obese, and one in six children are overweight or obese. Reflecting this reality, there are a large number of obese patients in the intensive care unit. Some 30-35% of adult ICU patients are obese, and 5% or more are morbidly obese. Patients who are both critically-ill and morbidly obese present unique challenges to care. These range from basic care, such as prevention of bedsores and ambulation, to sophisticated issues, such as medication dosing and ventilator management. It takes a team of caregivers, for example, to help a 400-pound patient in and out of bed. One of the most difficult aspects of the care of such patients is nutrition support, which is the subject of the present review.

Appropriate protein provision in critical illness: a systematic and narrative review

BACKGROUND

Widely varying recommendations have been published with regard to the appropriate amount of protein or amino acids to provide in critical illness.

OBJECTIVE

We carried out a systematic review of clinical trials that compared the metabolic or clinical effects of different protein intakes in adult critical illness and comprehensively reviewed all of the available evidence pertinent to the safe upper limit of protein provision in this setting.

DESIGN

MEDLINE was searched for clinical trials published in English between 1948 and 2012 that provided original data comparing the effects of different levels of protein intake on clinically relevant outcomes and evidence pertinent to the safe upper limit of protein provision to critically ill adults.

RESULTS

The limited amount and poor quality of the evidence preclude conclusions or clinical recommendations but strongly suggest that 2.0-2.5 g protein substrate · kg normal body weight⁻¹ · d⁻¹ is safe and could be optimum for most critically ill patients. At the present time, most critically ill adults receive less than half of the most common current recommendation, 1.5 g protein · kg⁻¹ · d⁻¹, for the first week or longer of their stay in an intensive care unit.

CONCLUSION

There is an urgent need for well-designed clinical trials to identify the appropriate level of protein provision in critical illness.

Nutritional and metabolic abnormalities and nutrition support therapy in patients with liver failure

Nutritional and metabolic damage is an important manifestation of severe liver disease and is significantly associated with prognosis. In this paper, we review nutritional and metabolic abnormalities and nutritional support therapy in patients with liver failure by summarizing the indicators for evaluating the nutritional and metabolic status and the features of nutrients and energy metabolism. We point out that resting energy expenditure can be measured using CCM-D nutrition metabolism test system in liver failure patients. Energy supply is primarily contributed by fat oxidation in patients with chronic liver failure, and their respiratory quotient is significantly lower than the predicted values. In addition, we discuss nutritional support intervention methods and intake for different stages of liver failure. Our aim is to raise the awareness of clinicians for malnutrition in patients with liver failure to formulate individualized nutrition support therapy.

[Guidelines for specialized nutritional and metabolic support in the critically ill-patient. Update. Consensus of the Spanish Society of Intensive Care Medicine and Coronary Units-Spanish Society of Parenteral and Enteral Nutrition (SEMICYUC-SENPE): obese patient]

As a response to metabolic stress, obese critically-ill patients have the same risk of nutritional deficiency as the non-obese and can develop protein-energy malnutrition with accelerated loss of muscle mass. The primary aim of nutritional support in these patients should be to minimize loss of lean mass and accurately evaluate energy expenditure. However, routinely-used formulae can overestimate calorie requirements if the patient's actual weight is used. Consequently, the use of adjusted or ideal weight is recommended with these formulae, although indirect calorimetry is the method of choice. Controversy surrounds the question of whether a strict nutritional support criterion, adjusted to the patient's requirements, should be applied or whether a certain degree of hyponutrition should be allowed. Current evidence suggested that hypocaloric nutrition can improve results, partly due to a lower rate of infectious complications and better control of hyperglycemia. Therefore, hypocaloric and hyperproteic nutrition, whether enteral or parenteral, should be standard practice in the nutritional support of critically-ill obese patients when not contraindicated. Widely accepted recommendations consist of no more than 60-70% of requirements or administration of 11-14 kcal/kg current body weight/day or 22-25 kcal/kg ideal weight/day, with 2-2.5 g/kg ideal weight/day of proteins. In a broad sense, hypocaloric-hyperprotein regimens can be considered specific to obese critically-ill patients, although the complications related to comorbidities in these patients may require other therapeutic possibilities to be considered, with specific nutrients for hyperglycemia, acute respiratory distress syndrome (ARDS) and sepsis. However, there are no prospective randomized trials with this type of nutrition in this specific population subgroup and the available data are drawn from the general population of critically-ill patients. Consequently, caution should be exercised when interpreting these data.

Nutrition delivery for obese ICU patients: delivery issues, lack of guidelines, and missed opportunities

The most appropriate enteral formula for the severely obese population has yet to be determined. The obese patient in the intensive care unit (ICU) creates numerous difficulties for managing care, one being the ability to deliver appropriate and timely nutrition. Access for nutrition therapy, either enteral or parenteral, can also create a challenge. Currently, no specific guidelines are available on a national or international scale to address the issues of how and when to feed the obese patient in the ICU. A bias against feeding these patients exists, secondary to the perception that an enormous quantity of calories is stored in adipose tissue. Making a specialty enteral formula for obesity from existing commercial formulas and other modular nutrient components is not practical, secondary to difficulty with solubility issues, dilution of the formula, and safety concerns. Using today's concepts and current metabolic data, a formula could be produced that would address many of the specific metabolic derangements noted in obesity. This formula should have a high-protein, low-carbohydrate content with at least a portion of the lipid source coming from fish oil. Specific nutrients that may be beneficial in obesity include arginine, glutamine, leucine, L-carnitine, lipoic acid, S-adenosylmethionine, and betaine. Certain trace minerals such as magnesium, zinc, and selenium may also be of value in the obese population. The concept of a specific bariatric formulation for the ICU setting is theoretically sound, is scientifically based, and could be delivered to patients safely.

Nutritional support of the obese and critically ill obese patient

With the dramatic increase in the prevalence of obesity worldwide and in the United States, it is virtually certain that clinicians will be caring for bariatric and obese nonbariatric patients in increasing numbers. This patient population presents several difficulties from the medical and surgical management perspectives. In particular, nutrition of the bariatric patient and critically ill obese patient is challenging. A clear understanding of the nutritional assessment and unique management strategies available for the bariatric and the critically ill obese patient is essential to provide them with the safest and most effective care.

Body composition (sarcopenia) in obese patients: implications for care in the intensive care unit

The study of body composition is a rapidly evolving science. In today's environment, there is a great deal of interest in assessing body composition, especially in the obese subject, as a guide to clinical and nutrition interventions. There are some strikingly different compartments of body composition between the obese and the lean patient. We do have the ability to measure body composition accurately, although these techniques can be labor intensive and expensive. The recognition of patients with sarcopenic obesity has identified a potential high-risk patient population. These body composition abnormalities may have even greater importance in the intensive care patient.

Current strategies of critical care assessment and therapy of the obese patient (hypocaloric feeding): what are we doing and what do we need to do?

Two of the most challenging issues in the clinical management of the obese patient are assessing energy requirements and whether hypocaloric (permissive) underfeeding should be employed. Multiple predictive equations have been used in the literature to estimate resting metabolic rate, although no consensus has emerged regarding which prediction equation is most accurate and precise in the obese population. Hypocaloric, or permissive underfeeding, specifically refers to the intentional administration of calories that are less than predicted energy expenditure. Thus far, very few studies performed have been performed to assess the efficacy of hypocaloric feeding in the obese hospitalized patient. It is concluded that the optimal caloric intake of obese patients in the intensive care unit remains unclear given the limitation of the existing data.

Nutrition support for the acute lung injury/adult respiratory distress syndrome patient: a review

Support for Acute Lung Injury (ALI) and Adult Respiratory Distress Syndrome (ARDS) in many ways represents the summation of all intensive care unit nutrition modalities. Basic tenets of management are based on those established for the general population of mechanically ventilated patients. As a marker of critical illness however, patients with ALI/ARDS suffer from other organ dysfunctions that require advanced support. Specific issues to be considered in this population include carbon dioxide production, prevention of aspiration, and modulation of the inflammatory response. These particular areas, with special attention paid to the role of lipids in ALI/ARDS, will be reviewed.

Intensive care in the obese

Nearly 20% of all patients admitted to an intensive-care unit are obese. Their excess weight puts them at risk for several problems and complications during their intensive-care unit stay. Especially, pulmonary problems need particular attention, and comprehensive knowledge of the specific pathophysiologic changes of the respiratory system is important. Lung protective ventilation strategies, supplemented by lung-recruiting manoeuvres, may be feasible in critically ill obese patients with lung injury. Careful positioning of the obese is essential to optimise ventilation and facilitate weaning from mechanical ventilation. Optimal hypocaloric nutrition with a high proportion of proteins is advised to control hyperglycaemia. Because mortality in obese patients is similar to or lower than in non-obese ones, it is conceivable that obesity has a protective effect in the critically ill.

Inpatient enteral and parenteral [corrected] nutrition for patients with diabetes

Both glycemic control and adequate nutrition support impact the clinical outcome of hospitalized patients. Providing nutrition to malnourished patients using the enteral or parenteral route may increase the risk of hyperglycemia, especially in patients with diabetes. Hyperglycemia can be managed through the use of enteral tube feeds with reduced carbohydrate content or limiting the carbohydrate concentration in parenteral formulas. Judicious use of insulin or other glucose-lowering medications synchronized with appropriate nutrition support allows for optimal inpatient glycemic control.

Difficulties in managing the surgical patient who is morbidly obese

Managing patients who are morbidly obese in the intensive care unit is associated with a variety of problems uncommonly experienced with the those who are not morbidly obese. Clinicians experience a myriad of unique problems and circumstances, from the need for special beds and lifts to unusual and unknown volumes of distribution resulting in unclear drug dosing. This review examines several issues including sedation, invasive monitoring, venous thromboembolism prophylaxis, surgical infections, nutritional support, and other complications that may be of particular importance to the critically ill patient who is morbidly obese. In many cases, care is altered based on the complicating issues surrounding morbid obesity. In other cases, the presence of obesity suggests no alterations in our routine critical care delivery. A comprehensive review of the literature is undertaken, data are critically considered, and overall opinion is rendered based on the available peer-reviewed literature. In many cases, data are not available that address the specific patient population in question, so related papers (like gastric bypass data) are considered. Many issues do not have definitive answers based on randomized controlled trials, and much is left to treating clinician opinion and local practice patterns. Where good data exist, however, one should consider carefully and individually deviation from the evidence-based approach.