Nutrition in Intensive Care Medicine: Beyond Physiology

P. Singer

• Publisher: S. Karger
• Year: 2012
• ISBN:
  9783318022285
• Topic: Medicine
• Subtopic: Public Health, Administration & Care

The care of ICU patients has seen many improvements over the years, both with regard to technical aspects and supportive measures. The first part of this book analyzes nutritional support at various levels, ranging from the cell level to the whole-body aspect; drawing on recent prospective randomized studies, the authors propose a new approach for oral, enteral and/or parenteral nutrition. The second part underlines the interference between nutrition and outcome to reach recovery, giving to this field an increased importance for better short and long term management: The best glucose control, individualized nutritional support and the avoidance of harmful interferences is extensively discussed. The final part deals with patients suffering from multi-organ failure and the need for a better understanding of the interactions between disease and nutrition. Identification of the metabolic condition of the patient, existence or not of evidence-based medicine, expert opinion, treatment opportunities and the case manager recognizing threats are all integrated to reach the appropriate decision. This last part will help the reader to untangle the complexity of the ICU patient of the 21st century and to propose a personalized nutritional support process.

Organ-Targeted Nutrition

Singer P (ed): Nutrition in Intensive Care Medicine: Beyond Physiology.
World Rev Nutr Diet. Basel, Karger, 2013, vol 105, pp 106–115

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The Surgical/Trauma Patient

Arved Weimann

Klinik für Allgemein-und Visceralchirurgie, Klinikum St. Georg gGmbH Leipzig, Leipzig, Germany

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Abstract

In aiming for enhanced recovery and the reduction of postoperative morbidity, enhanced recovery after surgery concepts have introduced a new era in perioperative management. It is frequently not recognized that the enhanced recovery after surgery protocol does not overcome the necessity for appropriate perioperative nutritional and metabolic care, particularly with those in intensive care. Early detection and preoperative conditioning of patients at nutritional risk remains essential. In patients at risk where inadequate oral intake is anticipated for a longer period, nutritional support should be started early via the enteral route, possibly in combination with parenteral nutrition. For early enteral nutrition in the intensive care unit, a slow increase in the administration rate is recommended while observing the enteral tolerance by abdominal distension and gastric aspirate. While the length of time before combining enteral and parenteral nutrition with the appropriate supplementation is still under debate, immunomodulating substrates and diets have proven benefits in surgical high-risk patients.

Copyright © 2013 S. Karger AG, Basel

In ‘Nutrition therapy for the critically ill surgical patient: we need to do better!’, Drover et al. [1] showed that surgical intensive care patients received less nutrition than medical patients, stating: ‘Cardiovascular and gastrointestinal surgery patients are at highest risk of iatrogenic malnutrition’. The following review attempts to analyze and discuss the issue of nutrition therapy in surgical intensive care unit (ICU) patients with regard to the current guidelines and the recent literature.

According to the prospective data from a multicentric observational study, in hospitals most patients at risk will be found in the departments of surgery, oncology, geriatrics, and intensive care medicine. The hospital complication rate is significantly influenced by nutritional risk, severity of the disease, age >70 years, surgery, and cancer disease [2]. Just recently, lower food intake before hospital admission was shown to be an independent risk factor for complication rate in patients undergoing abdominal surgery [3]. Bearing in mind the demographic development in the Western world, surgeons will face an increase in the number of elderly patients at nutritional risk undergoing major surgery for cancer.

Systematic assessment of risks, including nutritional risk screening, has been recommended for all patients on hospital admission. According to the guidelines of the European Society for Clinical Nutrition and Metabolism (ESPEN), a severe metabolic risk has to be considered with the presence of one or more of the following criteria [4]:

1 Weight loss >10-15%

2 BMI<18.5

3 Serum-albumin <30 g/l (no hepatic or renal disease).

Indication for Nutritional Support

Despite the convincing and clear metabolic advantages of the enhanced recovery after surgery concepts [5], there is still a considerable risk for hypocaloric nutrition and delay of adequate nutritional support in non-identified metabolic risk patients and those developing postoperative complications requiring intensive care.

The following recommendations are in accordance with the ESPEN guidelines from 2006 and 2009 [5, 6]. Inadequate oral intake for more than 14 days is associated with a higher mortality. Nutritional support is therefore indicated even in patients without obvious undernutrition if it is anticipated that the patient will be unable to eat for more than 7 days perioperatively. It is also indicated in patients who cannot maintain oral intake above 60% of the recommended intake for more than 10 days. In these situations, nutritional support (by the enteral route if possible) should be initiated without delay. In case the tolerance to oral fluid and food intake is rather limited for more than 4 days, it may be recommended to begin peripheral parenteral hypocaloric nutrition (e.g. two-chamber bag).

Preoperative Nutritional Strategies

In order to facilitate enhanced recovery after surgery, diminish the complication rate, and avoid longer stays in the ICU, different concepts for improving patient nutritional status, before major surgery are available. These are:

1 Substitution of caloric deficiency in case of severe metabolic risk,

2 Metabolic conditioning (carbohydrate load),

3 Immunologic preconditioning.

Caloric Deficiency

It has remained unchanged that ‘most patients will benefit from prompt surgery’ [5, 6]. In order to restore caloric deficiency, prolongation of surgery may only be reasonable in the case of undernutrition and severe metabolic risk. If nutritional support is indicated, the enteral route should be preferred. Whenever possible, enteral nutrition should be performed prior to hospital stay in order to avoid nosocomial infections [6]. Parenteral nutrition is recommended in severely undernourished patients who cannot be adequately orally or enterally fed. Usually, nutritional support is administered for 7-14 days [5, 6].

Metabolic Conditioning

Preoperative fasting is unnecessary for most patients. Related to overnight fasting, the metabolic burden of perioperative hypoglycemia has clearly been shown. Preoperative carbohydrate drinks can be recommended for most patients without significantly impairing gastric emptying. In the rare situation of patients who cannot be fed by the oral/enteral route, a glucose infusion should be administered intravenously [5, 6]. In several prospective randomized controlled trials (RCT), significant advantages were shown in favor of carbohydrate loading. These included less postoperative discomfort and shortened length of hospital stay after colorectal surgery. However, a recent well-designed prospective RCT with 142 patients undergoing open colorectal or liver surgery did not reveal any significant clinical advantage for the carbohydrate drink. Only plasma cortisol level was significantly lower on postoperative day 1, which could be related to stress reduction [7]. Other preoperative drinks, which are additionally enriched with glutamine, are currently under investigation [8]. In pancreatic surgery, preconditioning with glutamine, antioxidants, and green tea extract versus placebo significantly elevated vitamin C levels and improved total endogenous antioxidant capacity. However, oxidative stress and inflammatory response were not reduced [9].

Immunologic Preconditioning

So-called ‘immunonutrition’ refers to the use of formulas, enriched with arginine, omega-3 -fatty acids, glutamine, and nucleotides.

Those who benefit most from these formulas are patients with obvious severe nutritional risk, patients undergoing major cancer surgery of the neck (laryngectomy, pharyngectomy) and of the abdomen (esophagectomy, gastrectomy, and pancreatoduodenectomy), as well as after severe trauma. This recommendation was recently emphasized in the American Society for Parenteral and Enteral Nutrition (ASPEN) Guidelines for critically ill adult patients [10]. Immune-modulating formulas contribute to a decreased rate of postoperative infections, and consequently to a decreased length of stay in the hospital. This has been reconfirmed by the results of three recent meta-analyses for surgical high-risk patients [11–13].

Whenever possible, administration of these immune-modulating formulas should be started 5-7 days before and continued 5-7 days after surgery. In a recent prospective RCT with patients after major abdominal cancer surgery, no advantages were found for the administration of this formula when given only after surgery [14]. Therefore, it is likely that patients will benefit most by preoperative supplementation. It remains open whether future studies should focus on immunologic conditioning by ‘pharmaconutrition’ using single substances. In a recent single-substance prospective RCT, high-risk patients undergoing esophagogastrectomy were compared, using omega-3 fatty acid-supplemented enteral nutrition versus standard enteral nutrition for 7 days before and after surgery. No difference was observed in morbidity and mortality or HLA-DR expression on either monocytes or activated T lymphocytes [15].

Postoperative Nutrition

In general, interruption of nutritional intake is unnecessary. A recent meta-analysis has clearly re-emphasised no increase of risk for developing anastomotic leakage after surgery of the gastrointestinal tract [16]. When anastomoses of the upper gastrointestinal tract have been performed, early oral food intake is feasible and not harmful to the patient, as shown by Hur et al. [17]. While no reasonable rationale exists for longer periods of fasting, oral food intake should follow gastrointestinal tolerance. If indicated, additional enteral nutrition can be delivered via a tube, with the tip placed distally to the anastomosis [6].

Enteral Tube Feeding

Patients who benefit most from postoperative tube feeding are those who have just had major cancer surgery to the abdomen and head and neck - laryngectomy, pharyngectomy, esophageal resection, gastrectomy, partial (pylorus preserving) pancreatoduodenectomy - as well as those suffering from severe trauma. In these patients, it may be reasonable to create safe enteral access via a nasojejunal tube or fine-needle catheter jejunostomy at the time of surgery. It has been shown that for decompression after gastrectomy, nasojejunal tubes bear considerable discomfort for many patients and may be unnecessary. For feeding reasons this favors fine-needle catheter jejunostomy.

Ischemic bowel necrosis is an uncommon life-threatening complication which may occur in cases of gastrointestinal intolerance, related to an inappropriately high enteral feeding amount, especially when a...