Specialized Nutrition Support in the Hospitalized Obese Patient

Validation of predictive equations for resting energy expenditure in treatment-seeking adults with overweight and obesity: Measured versus estimated

The quantification of resting energy expenditure (REE) in patients with obesity is an important measure. We aimed to evaluate the validity of predictive equations in estimating REE compared with indirect calorimetry (IC) in treatment-seeking Arab adults with overweight or obesity. Twenty-three predictive equations were compared with REE values measured by IC (Vmax Encore 229) in 89 adult participants with overweight or obesity (mean age = 40.62 ± 15.96 years and mean body mass index [BMI] = 35.02 ± 4.60 kg/m²) referred to the Department of Nutrition and Dietetics of Beirut Arab University (Lebanon). The accuracy of the predictive equations was evaluated on the basis of whether the percentage prediction was within 10% of the measured REE, and the mean difference between predicted and measured values (bias). The Bland-Altman method was used to assess the agreement between the predicted and measured values. The equations that demonstrated the closest agreement with IC were the De La Cruz equation in males (accurate predictions: 68.2%; bias: -19.52 kcal/day) and the Mifflin equation in females (accurate prediction: 61.2%; bias: -36.43 kcal/day). In conclusion, we suggest that these two equations produce the least biased estimations for REE in this population.

Predictive Equations Based on Body Composition for Resting Energy Expenditure Estimation in Adults with Obesity

BACKGROUND AND AIM

An accurate estimation of Resting Energy Expenditure (REE) in patients with obesity is crucial. Therefore, our aim was to assess the validity of REE predictive equations based on body composition variables in treatment-seeking Arab adults with obesity.

METHODS

Body composition and REE were measured by Tanita BC-418 bioimpedance and Vmax Encore 229 IC, respectively, and predictive equations based on fat mass and fat-free mass were used in REE estimations among 87 adults of both genders, in the Outpatient Clinic in the Department of Nutrition and Dietetics at Beirut Arab University (Lebanon). The mean differences between the measured and estimated REE values were calculated to assess the accuracy, and the Bland-Altman method was used to assess the level of agreement.

RESULTS

Ten predictive equations were included. In males, all the predictive equations gave significantly different estimates of REE when compared to that measured by IC. On the other hand, in females, the mean difference between the REE value estimated by Huang and Horie-Waitzberg equations and that measured using IC was not significant, and the agreement was confirmed using Bland-Altman plots.

CONCLUSION

Huang and Horie-Waitzberg equations are suggested for accurate REE estimation in females; however, new validated REE estimation equations for males in this population are still needed.

High-Protein Hypocaloric Nutrition for Non-Obese Critically Ill Patients

High-protein hypocaloric nutrition, tailored to each patient's muscle mass, protein-catabolic severity, and exogenous energy tolerance, is the most plausible nutrition therapy in protein-catabolic critical illness. Sufficient protein provision could mitigate the rapid muscle atrophy characteristic of this disease while providing urgently needed amino acids to the central protein compartment and sites of tissue injury. The protein dose may range from 1.5 to 2.5 g protein (1.8-3.0 g free amino acids)/kg dry body weight per day. Nutrition should be low in energy (≈70% of energy expenditure or ≈15 kcal/kg dry body weight per day) because efforts to match energy provision to energy expenditure are physiologically irrational, risk toxic energy overfeeding, and have repeatedly failed in large clinical trials to demonstrate clinical benefit. The American Society for Parenteral and Enteral Nutrition currently suggests high-protein hypocaloric nutrition for obese critically ill patients. Short-term high-protein hypocaloric nutrition is physiologically and clinically sensible for most protein-catabolic critically ill patients, whether obese or not.

Indirect Calorimetry: A Practical Guide for Clinicians

This review provides clinicians with a comprehensive overview of indirect calorimetry including the principles, methodology, technologic advancements, benefits, and challenges. Clinical applications for indirect calorimetry and the potential limitations are specifically addressed for both the inpatient and outpatient setting. Measurement of energy expenditure is the most accurate method to assess energy needs. Indirect calorimetry remains a gold standard in measuring energy expenditure in the clinical settings. The benefits of providing optimal nutrition for recovery from illness and chronic health management are well documented. Indirect calorimetry offers a scientifically-based approach to customize a patient's energy needs and nutrient delivery to maximize the benefits of nutrition therapy. With recent advances in technology, indirect calorimeters are easier to operate, more portable, and affordable. Increased utilization of indirect calorimetry would facilitate individualized patient care and should lead to improved treatment outcomes.

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.

Optimal caloric intake for critically ill patients: first, do no harm

Despite considerable efforts to define energy requirements for critically ill patients, no single method has been found to be precise and unbiased for all patients. As a result, clinicians have used various methods that may overestimate energy requirements for some patients. Provision of target caloric intake without regard to the complications of overfeeding, such as hyperglycemia, hypercapnia, or gastric feeding intolerance, could result in overall detrimental clinical outcome. Inadequate nutrition support is also associated with adverse clinical outcomes that necessitate optimization of delivery and tolerance of the nutrition regimen. A pivotal paper by Krishnan and colleagues published in 2003 brought these issues to the forefront of clinical practice. Key papers that support or refute the practice of "permissive underfeeding" are reviewed. Further research is necessary to determine the minimum amount of nutrition required to achieve a therapeutic benefit as well as to ascertain at what amount of additional nutrition intake offers no further improvement in clinical outcome.

Feeding Practices of Severely Ill Intensive Care Unit Patients: An Evaluation of Energy Sources and Clinical Outcomes

OBJECTIVE

The quantity of nutrition that is provided to intensive care unit (ICU) patients has recently come under more scrutiny in relation to clinical outcomes. The primary objective of this study was to assess energy intake in severely ill ICU patients and to evaluate the relationship of energy intake with clinical outcomes.

DESIGN

Prospective cohort study.

SUBJECTS/SETTINGS

Seventy-seven adult surgery and medical ICU patients with length of ICU stay of at least 5 days.

STATISTICAL ANALYSES PERFORMED

Student's t test and chi2 tests were used to examine ICU populations. To determine the relationship of patient variables to hospital length of stay and ICU, length of stay regression trees were calculated.

RESULTS

Both groups were underfed with 50% of goal met in surgical ICU and 56% of goal met in medical ICU. Medical ICU patients received less propofol and significantly less dextrose-containing intravenous fluids when compared to surgical ICU patients (P=0.013). From regression analysis, approaching full nutrient requirements during ICU stay was associated with greater hospital length of stay and ICU length of stay. For combined groups, if % goal was > or =82%, the estimated average value for ICU length of stay was 24 days; whereas, if the % goal was <82%, the average ICU length of stay was 12 days. This relationship held true for hospital length of stay.

CONCLUSIONS

Medical and surgical ICU patients were insufficiently fed during their ICU stay when compared with registered dietitian recommendations. Medical ICU patients received earlier nutrition support, on average more enteral nutrition, with fewer kilocalories supplied from lipid-based sedatives and intravenous fluid relative to surgical ICU patients. Based upon length of stay, the data suggest that the most severely ill patient may not benefit from delivery of full nutrient needs in the ICU.

Indirect calorimetry: methodology, instruments and clinical application

PURPOSE OF REVIEW

This review aims to identify the basic methods for accurately measuring a patient's energy expenditure in clinical nutrition practice by indirect calorimetry, and the impact upon a disease state of applying the results obtained.

RECENT FINDINGS

The open-circuit method is the most widely used in the majority of classical instruments for measuring energy consumption. Advances in gas exchange measurement have made this technique readily and precisely available at the bedside. Nevertheless, it is important to understand its intricate primary methodology for safe and correct application. The stress and activity factors should be carefully and specifically applied, and the respiratory quotient abandoned, for tailoring a patient's daily nutrition regimens. Caloric expenditure measured by indirect calorimetry coupled with the doubly labeled water technique introduced the concept of physical activity energy expenditure, which added to resting energy expenditure results in total daily energy expenditure. Compact modular and handheld devices have been introduced into the market, together with similar technology for evaluating exercise energy expenditure, making utilization easier, safer and precise. In the critically ill population, which is exposed to medical and surgical interventions, indirect calorimetry has greatly changed the practice of caloric administration, significantly reducing the total daily amount.

SUMMARY

In conclusion, one has to be careful when choosing devices, and understanding and clinically applying the results obtained by indirect calorimetry, bearing in mind that measured resting energy expenditure should be the daily caloric goal in order to diminish clinical morbidity.

Morbid obesity and nutrition support: is bigger different?

Morbid obesity (body mass index >40 kg/m2 or >35 kg/m2 in the presence of an severe-obesity-related comorbid disease) is increasing in frequency in the United States and worldwide. This population has a variety of medical and surgical disorders that result in hospitalizations. It is not unexpected to encounter these patients on the nutrition support service. The obesity comorbid diseases that may increase complications related to nutrition support are present in greater frequency and severity in the morbidly obese population than in the nonobese population. To reduce these potential complications, strategies of hypocaloric nutrition have been advocated for obese patients, and this study focuses specifically on the morbidly obese subset.

Can measured resting energy expenditure be estimated by formulae in daily clinical nutrition practice?

PURPOSE OF REVIEW

To recognize the fundamental factors that alter energy expenditure on a daily basis and the impact they have on the measurement of caloric consumption by the human body, through respiratory indirect calorimetry, and thus to try to determine which predictive equation best correlates with total energy expenditure generated from energy measurements.

RECENT FINDINGS

The most important compartment of the body, for its metabolic activity and influence upon resting metabolic rate, is fat-free mass. Other variables affecting energy expenditure are sex, weight, height, age, body surface area, fat mass and ethnicity. Metabolic and activity factors such as the thermic effect of nutrients, facultative thermogenesis, anabolism/growth and physical activity, also contribute, comprising total daily energy expenditure. Following the pioneering work of Harris and Benedict for the estimation of energy expenditure, several authors turned their experimental interest to this area, and various recent predictive formulae were derived. These are useful and easy to apply in daily clinical nutrition practice. However, because of the cited variables upon energy expenditure, the final daily caloric estimates show inherent errors ranging from -23.5 to +22.5% upon measured caloric expenditure. These are particularly remarkable in critically ill patients who are exposed to medical and surgical interventions.

SUMMARY

One has to be careful in choosing, understanding and clinically applying the results from predictive equations, bearing in mind that the original population from which the equation was derived does not always correspond to that currently being evaluated.

Hypocaloric feeding of obese patients in the intensive care unit

PURPOSE OF REVIEW

Given the increased awareness of the detrimental complications of overfeeding, particularly hyperglycemia, the safety and efficacy of specialized nutritional support for the critically ill obese patient is of major concern. The intent of this review is to provide the scientific foundation, supporting and conflicting literature, for the implementation of hypocaloric, high-protein specialized nutritional support for acutely ill, hospitalized patients with obesity.

RECENT FINDINGS

Similar anabolic equivalencies can be achieved with hypocaloric, high-protein nutritional support compared with a more traditional higher calorie, lower protein regimen. The provision of additional calories worsens hyperglycemia, results in a further accumulation of fat mass, and increases the potential for overfeeding without significant net protein anabolism gain.

SUMMARY

The current literature indicates that hypocaloric, high-protein enteral or parenteral nutrition is promising as the standard of practice for the metabolic support of the critically ill obese patient. The achievement of net protein anabolism and the avoidance of overfeeding complications are the primary goals, with fat weight loss a welcome secondary benefit.