Protein Requirements during Hypocaloric Nutrition for the Older Patient With Critical Illness and Obesity: An Approach to Clinical Practice

Current guidelines recommend a hypocaloric, high protein nutrition regimen for patients with obesity and critical illness. The impact of advancing age presents with unique challenges in which a greater protein intake is required to overcome the anabolic resistance associated with aging in the face of presumed decreased renal function. The primary objective of this review is to provide an overview of the impact of obesity and advancing age on protein requirements for patients with critical illness and review the scientific evidence supporting the rationale for hypocaloric, high protein nutrition for this subpopulation, as well as provide some practical suggestions for their clinical management.

Metabolic support challenges with obesity during critical illness

Adiposity-based chronic disease, critical illness, and nutrition therapy increase the risk for overfeeding and worsened nutritional and clinical outcomes. Hypocaloric, high-protein nutrition therapy provides critically ill obese patients the opportunity to achieve net protein anabolism with a reduced risk for overfeeding-related complications. The intent of this review is to discuss the impact of obesity on clinical outcomes, describe the consequences of obesity that increase complications associated with nutrition therapy, provide the framework to develop a hypocaloric, high-protein regimen, review the scientific evidence to support this mode of therapy, and discuss its limitations. Practical suggestions for patient monitoring are also provided.

Protein and Calorie Requirements Associated With the Presence of Obesity

Obesity compounds the metabolic response to critical illness and increases the risk for overfeeding complications due to its comorbidities. Hypocaloric, high-protein nutrition therapy affords the hospitalized patient with obesity the opportunity to achieve net protein anabolism with a reduced risk of overfeeding complications. The intent of this review is to provide the theoretical framework for development of a hypocaloric high-protein regimen, scientific evidence to support this mode of therapy, and unique considerations for its use in specialized subpopulations. Macronutrient goals and practical suggestions for patient monitoring are given.

Nutrition and metabolic support recommendations for the bariatric patient

Managing the metabolic needs of the patient with obesity is a challenge unto itself without the added demands of accounting for an altered gastrointestinal tract. Nevertheless, with about 200,000 bariatric procedures being performed annually in the United States, clinicians must be prepared to manage the critically ill bariatric surgery patient. This article reviews the recent literature relating to nutrient needs and metabolic support for the bariatric patient. Bariatric patients are at risk for several micronutrient deficiencies, including vitamins D and B₁₂, calcium, and iron; some bariatric procedures affect macronutrient needs as well. Literature on nutrition support guidelines for the bariatric population is limited. However, with an understanding of the anatomical and physiological effects of bariatric surgery, recent guidelines for critically ill patients with obesity can be applied to the bariatric surgery population. The unique needs of the bariatric population, such as susceptibility to micronutrient deficiencies and specialized access routes, must be considered to provide safe and efficacious nutrition support. Further research is necessary to develop specific nutrition support recommendations for the bariatric population.

Hypocaloric, high-protein nutrition therapy for critically ill patients with obesity

We published the first article that addressed hypocaloric, high-protein enteral nutrition therapy for critically ill patients with obesity more than 10 years ago. This study demonstrated that it was possible to successfully achieve this mode of therapy with a commercially available high-protein enteral formula and concurrent use of protein supplements. This study was also the first to demonstrate improved clinical outcomes with the use of hypocaloric, high-protein nutrition therapy. The results of this study, its unique findings, and shortcomings are discussed. Subsequent studies have added clarity to the effective use of this therapy, including its use in home parenteral nutrition patients, patients with class III obesity, and older patients with obesity.