Practicalities of nutrition support in the intensive care unit: the usefulness of gastric residual volume and prokinetic agents with enteral nutrition

The provision of early nutrition therapy to critically ill patients is established as the standard of care in most intensive care units around the world. Despite the known benefits, tolerance of enteral nutrition in the critically ill varies and delivery is often interrupted. Observational research has demonstrated that clinicians deliver little more than half of the enteral nutrition they plan to provide. The main clinical tool for assessing gastric tolerance is gastric residual volume; however, its usefulness in this setting is debated. There are several strategies employed to improve the tolerance and hence adequacy of enteral nutrition delivery in the critically ill. One of the most widely used strategies is that of prokinetic drug administration, most commonly metoclopramide and erythromycin. Although there are new agents being investigated, none are ready for routine application in the critically ill and the benefits are still being established. This review investigates current practice and considers the literature on assessment of enteral tolerance and optimization of enteral nutrition in the critically ill.     

Early nutrition support in the intensive care unit: a US perspective

PURPOSE OF REVIEW: Early nutrition support, defined as within the first 24-48 h of ICU care, is recommended by clinical practice guidelines. The purpose of this paper is to provide an evidence-based US perspective on early nutrition support in critical illness, explain its mechanism of action, and describe its implementation using combined enteral and parenteral nutrition support. RECENT FINDINGS: Recent American and Canadian guidelines recommend starting enteral nutrition within the first 24-48 h of ICU care. This is mainly due to accrued 'energy debt' from underfeeding in certain patients. This energy debt leads to increased risks of complications and longer lengths of stay. Strong clinical evidence, however, in the form of prospective, randomized, controlled intervention studies of early nutrition support in the setting of routine intensive insulin therapy, is lacking. SUMMARY: Early enteral nutrition should be first-line therapy in the ICU. If a caloric goal of 20-25 kcal/kg/day is not possible, then combined enteral and parenteral nutrition should be started. In the new age of intensive insulin therapy, parenteral nutrition has not been shown to confer significant additional infective risk. There are many unanswered questions, but a proactive posture for metabolic support in the ICU is advocated.     

Glycemic control and nutrition in the intensive care unit

PURPOSE OF REVIEW: Hospital clinicians frequently encounter hyperglycemia due to diabetes or the stress of critical illness in patients who are receiving nutrition support. RECENT FINDINGS: A growing body of evidence suggests that hyperglycemia in the hospital is associated with adverse outcomes (e.g. disability after acute cardiovascular events, infection and death) and that improvement in outcomes can be achieved with improved glycemic control or insulin. Therefore, familiarity with the implications of hyperglycemia and with its treatment are essential for clinicians practicing in hospital settings. SUMMARY: Questions persist regarding the optimal glucose goal range in differing patient groups. In addition, while the technology to deliver glycemic control in intensive care unit settings is widely available, data are limited about effective and safe insulin infusions. Research should focus on the risks and benefits of providing nutrition support in this group of patients, optimal glucose goal ranges, and on methods of achieving desired glucose goal ranges.     

Enteral access for nutrition in the intensive care unit

PURPOSE OF REVIEW: Enteral nutrition is the preferred route for nutrition support in the intensive care unit setting. This is usually delivered through nasoenteric feeding tubes in patients with an otherwise functional gastrointestinal tract. Placement of nasoenteric feeding tubes, however, may be difficult in this setting. Nasoenteric feeding tubes may be placed by multiple methods, each with their particular advantages and disadvantages. This review summarizes the recent literature on different methods of nasoenteric feeding tube placement with emphasis on critically ill patients. RECENT FINDINGS: Bedside assisted methods using electromyogram, electrocardiogram, and magnetic fields to provide immediate positional feedback to help guide tube advancement appear promising. Bedside methods using specific protocols, modified feeding tubes, prokinetics or magnetic assistance were also successfully reported. None of these methods has been prospectively compared with more commonly practiced methods in large studies. Endoscopic nasoenteric tube placement methods including transnasal approaches using ultra-thin endoscopes have been recently described and appear to be equivalent to fluoroscopic placement. All these recently reported techniques, however, may require more specialized equipment or training than is currently widely available. SUMMARY: Feeding tubes can be placed using bedside, fluoroscopic, and endoscopic means. Novel bedside methods have been recently described using immediate positional feedback or new assistive methods. Endoscopic techniques have similar success rates to fluoroscopic techniques and provide data on upper gastrointestinal abnormalities. There is no clear universal standard method. When feeding tube placement is required the technique used depends on local institutional resources and expertise.     

Early enteral nutrition in the cardiothoracic intensive care unit

BACKGROUND AND AIMS: Early enteral nutrition (EN) improves intestinal integrity, motility and immunocompetence. However, technical problems such as diarrhoea and gastric residual volumes are said to be associated with the method and have prevented its implementation. We have prospectively assessed clinical problems connected to early EN. PATIENTS AND METHODS: Seventy-three consecutive patients eligible for EN were assessed and observed until discharge from the intensive care unit (ICU) or until they resumed oral nutrition. They had surgery for coronary artery bypass grafting and/or valvular disease, thoracic or thoracoabdominal aortic aneurysms or other combined procedures. Two cardiac patients were not subjected to surgery. RESULTS: In 59/73 patients, EN was started within 3 days. EN was discontinued in half of the patients when they were able to feed themselves. Twelve patients vomited, one of them severely. Dislocation of the nasogastric tube occurred in 28 patients. The 15 patients with diarrhoea were treated with 2-6 broad-spectrum antibiotics during their ICU-stay. Out of 73, 40 patients did not show any gastric residual volume (GRV). GRV decreased during EN in 50% of the patients with fairly large or large residual volumes. The incidence of aspiration pneumonia was 10%. CONCLUSION: In the cardiothoracic ICU, individually adjusted early EN is feasible with few problems.     

Practicalities of nutrition support in chronic liver disease

The underlying causative agent in the majority of patients with chronic liver disease is ethanol; the rest of the cases are largely viral in aetiology (hepatitis B or C viruses). Nutrition supplementation improves the quality of life and decreases morbidity in chronic liver disease, but evidence that it prolongs long-term survival is lacking. The situation is very different in chronic liver disease patients who receive a liver transplant, however, with better pretransplantation nutrition status predicting a distinctly improved survival after transplantation.     

Outcomes in a pediatric intensive care unit before and after the implementation of a nutrition support team

BACKGROUND: We evaluated the effect of parenteral nutrition (PN) and enteral nutrition (EN) on in-pediatric intensive care unit (PICU) mortality before and after a continuous education program in nutrition support that leads to implementation of a nutrition support team (NST). METHODS: We used a historical cohort study of infants hospitalized for >72 hours at the PICU from 1992 to 2003. Five periods were selected (P1 to P5), considering the modifications incorporated into the program: P1, without intervention; P2, basic themes and original articles discussion; P3, clinical and nursing staff participation; P4, clinical visits; P5, NST. The samples were compared in terms of sex, age, admitting service (ie, medical vs surgical), prognostic index of mortality, length of stay (LOS), duration of mechanical ventilation, in-PICU mortality rate, and percentage of time receiving EN and PN for each patient. Bi- and multivariate analyses were performed. Statistical significance was set at 0.05 level. RESULTS: Progressive increase was observed in EN use (p = .0001), median values for which were 25% in P1 and rose to 67% by P5 in medical patients; there was no significant difference in surgical patients. A reduction was observed in PN use; in P1 medians were 73% and 69% for medical and surgical patients respectively, and decreased to 0% in P5 for both groups (p = .0001). There was significant reduction in-PICU mortality rate during P4 and P5 among medical patients (p < .001). The risk of death was 83% lower in patients that received EN for >50% of LOS (odds ratio, 0.17; confidence interval, 0.066-0.412; p = .000). CONCLUSIONS: The program motivated an increase in EN and a decrease in PN use, mainly after implementation of NST and reduced in-PICU mortality rate.     

A nutritional support team in the pediatric intensive care unit: changes and factors impeding appropriate nutrition

BACKGROUND & AIMS: The aims of this study were to determine the impact of a nutritional support team (NST) intervention in a pediatric intensive care unit (PICU) and to identify the factors at admission that were associated to a delay to achieve a sustained optimal caloric intake (SOCI). METHODS: Caloric and protein intake and nutritional parameters were compared in 82 children in 2000 and 2003, respectively before and after the introduction of a NST. Predictive factors of a delay to achieve the SOCI were identified using multivariate analysis. RESULTS: There was no difference in 2000 and 2003, respectively, regarding cumulative caloric deficits (19+/-15.7 vs. 20.7+/-14.8 kcal/kg day), cumulative protein deficits (0.26+/-0.31 vs. 0.22+/-0.20 g/kg day), time to achieve a SOCI (7 vs. 7 days). Factors at admission associated with a delay to achieve a SOCI were a pediatric risk of mortality (PRISM) score > 10 (hazard ratio 0.58; 95% CI 0.44-0.77), a CRP > 50 mg/L (hazard ratio 0.49; 95% CI 0.35-0.70), a fluid restriction (hazard ratio 0.51; 95% CI 0.37-0.71), and a weight for age > 3rd centile (hazard ratio 0.54; 95% CI 0.41-0.72). CONCLUSIONS: The intervention of a NST has not modified significantly the nutritional management. In pediatric intensive care, many factors identified at admission are associated with impairing appropriate nutrition.     

Enteral nutrition and cardiovascular medications in the pediatric intensive care unit

BACKGROUND: Enteral nutrition has multiple benefits for critically ill patients. However, the administration of enteral nutrition to patients requiring medications for cardiovascular support is controversial secondary to concerns of altered splanchnic perfusion. The objective of this study is to evaluate the tolerance of enteral nutrition in pediatric patients receiving cardiovascular medications. METHODS: This was a retrospective chart review of patients admitted to the pediatric intensive care unit at Children's Healthcare of Atlanta at Egleston in a 1-year period. Patients were eligible for the study if they received enteral nutrition during or within 24 hours of requiring continuous infusion of dopamine, dobutamine, epinephrine, norepinephrine, or neosynephrine. RESULTS: Fifty-five admissions (52 patients) met study criteria. Patients ranged in age from 1 month to 20 years old. Although a large number (71%) of patients experienced at least 1 feeding interruption, the majority (70%) of reasons cited for stopping or slowing feedings were not related to gastrointestinal (GI) tolerance. Only 29% of patients had feedings held for perceived intolerance. Vomiting was the most often-cited reason for these interruptions. Constipation was reported in 36% of patients but cited only 4 times as a reason for feeding interruption. Four patients exhibited evidence of GI bleeding. This bleeding was considered clinically insignificant in 2 patients and appeared unrelated to enteral feedings in the others. CONCLUSIONS: This study suggests that many pediatric patients receiving cardiovascular medications tolerate enteral nutrition without adverse events. Further prospective studies are needed to determine whether enteral nutrition can consistently benefit these critically ill pediatric patients.     

肠内与肠外两种营养支持疗法在重症监护病房危重症患者综合治疗中的应用比较

目的 比较肠内与肠外两种营养支持疗法在重症监护病房（ICU）危重症患者综合治疗中的疗效.方法 选择ICU危重症患者114例,按随机数字表法分为肠内营养组（57例）和肠外营养组（57例）,治疗2周后比较两组血红蛋白、总蛋白、白蛋白、前清蛋白等营养指标及并发症发生情况.结果 两组患者治疗2周后各营养指标均有所升高,且肠内营养组比肠外营养组升高更明显[血红蛋白：（120.47±22.46） g/L比（114.83±23.86） g/L,总蛋白：（78.21±8.42） g/L比（70.48±8.21） g/L,白蛋白：（38.21±5.03） g/L比（33.87±5.62） g/L,前清蛋白：（245.57±44.61） mg/L比（182.24±42.73） mg/L],差异有统计学意义（P＜0.05）.肠内营养组腹胀腹泻、呕吐恶心、感染、肝肾功能损伤发生率均明显低于肠外营养组[14.04％（8/57）比26.32％ （15/57）,12.28％（7/57）比17.54％（10/57）,3.51％（2/57）比8.77％（5/57）,1.75％（1/57）比5.26％ （3/57）],差异均有统计学意义（P＜0.05）.结论 营养支持对于危重症患者的营养状况和机体免疫力都有提升作用,且肠内营养效果更加明显,可更好地提高预后,可能成为危重症患者更佳的营养支持疗法.     

Implementation of a nutrition support protocol increases the proportion of mechanically ventilated patients reaching enteral nutrition targets in the adult intensive care unit

BACKGROUND: Despite the evidence that enteral feeding reduces morbidity in critically ill patients and is preferred to parenteral nutrition, the delivery of enteral nutrition (EN) is often inadequate. The purpose of this study was to determine whether implementation of an evidence-based nutrition support (NS) protocol could improve EN delivery. METHODS: An NS protocol incorporating available scientific evidence; data from a retrospective survey of 30 intensive care unit (ICU) patients; and input from dietitians, intensive care physicians, surgeons, nurses, and pharmacists was developed. The impact of this protocol was evaluated prospectively in 123 consecutive adult patients admitted to a multisystem ICU who were eligible for EN. RESULTS: The percentage of patients who received at least 80% of their estimated energy requirements during their ICU stay increased from 20% before implementation of the NS protocol to 60% after implementation (p < .001). After adjusting for confounders, those in the postimplementation group received significantly more kcal/kg/d than the preimplementation group (3.71 kcal/kg/d; 95% confidence interval, 1.64 to 5.78; p = .001). Parenteral nutrition use [corrected] was reduced in the postimplementation group (1.6 vs 13%, p = .02). There was no difference in time to initiation of enteral nutrition between groups (1.76 days preprotocol vs 1.44 days postprotocol implementation, p = .9). CONCLUSIONS: The development and use of an evidence-based NS protocol improved the proportion of enterally fed ICU patients meeting their calculated nutrition requirements.     

Enteral nutrition in the cardiothoracic intensive care unit: challenges and considerations

Cardiovascular disease is a common preexisting condition among hospitalized patients. Acute myocardial infarction and cardiac surgery account for 2 of the most common reasons patients are admitted to the intensive care unit. Determining how and when to feed these patients is a constant challenge presented to nutrition support practitioners. Enteral nutrition has emerged as the preferred route of feeding particularly in critical illness. By providing enteral nutrition instead of parenteral nutrition, the natural physiologic pathway is being followed and gut immunity preserved. However, obstacles such as upper gastrointestinal intolerance, hypoperfusion vasopressor support, and glycemic control make the task of initiating feeds a challenge. Once a patient has successfully tolerated feeds, the nutrition support clinician must still determine how much to feed and if specialty formulas such as those containing omega-3 fatty acids are beneficial for their patient. The purpose of this review is to present recent research on the feeding challenges in the critical care population with a focus on the cardiothoracic population and an emphasis on improving patient outcomes.     

The nutritional and metabolic support of heart failure in the intensive care unit

PURPOSE OF REVIEW: Heart failure and cardiovascular disease are common causes of morbidity and mortality, contributing to many ICU admissions. Nutritional deficiencies have been associated with the development and worsening of chronic heart failure. Nutritional and metabolic support may improve outcomes in critically ill patients with heart failure. This review analyzes the role of this support in the acute care setting of the ICU. RECENT FINDINGS: Cardiac cachexia is a complex pathophysiologic process. It is characterized by inflammation and anabolic-catabolic imbalance. Nutritional supplements containing selenium, vitamins and antioxidants may provide needed support to the failing myocardium. Evidence shows that there is utility in intensive insulin therapy in the critically ill. Finally, there is an emerging metabolic role for HMG-CoA reductase inhibition, or statin therapy, in the treatment of heart failure. SUMMARY: Shifting the metabolic milieu from catabolic to anabolic, reducing free radicals, and quieting inflammation in addition to caloric supplementation may be the key to nutritional support in the heart failure patient. Tight glycemic control with intensive insulin therapy plays an expanding role in the care of the critically ill. Glucose-insulin-potassium therapy probably does not improve the condition of the patient with heart failure or acute myocardial infarction.     

早期营养治疗与有创机械通气病人28 d病死率的预测因素研究

目的:研究呼吸重症监护病房(RICU)有创机械通气病人早期营养治疗及其他因素对28 d病死率的影响. 方法:将呼吸衰竭行气管插管的64例病人分为存活组和病死组.记录血清清蛋白(ALB)水平、APACHEⅡ评分和并发症情况,营养支持方式(包括完全肠内营养和混合营养),分析影响28 d病死率的因素. 结果:混合效应模型分析显示,入住RICU时间是个显著的预测变量(P＜0.05),分组不是显著的预测变量(P＞0.05).而入住RICU时间和分组的交互效应是个显著的预测变量(P＜0.05).包含五个变量:第1天实际热量/标准热量、第2天实际热量/标准热量、1周后清蛋白、呼吸机相关性肺炎(VAP)、肾功能衰竭的判别分析显示Wilks's Lambda是显著的(P＜0.05),表明该模型能预测第28天病人是否死亡. 结论:①早期(48 h内)摄入热量与28 d病死率有关.②五个变量的模型对第28天病死率正确的预测为83.3％,对存活正确的预测为72.7％.     

Acinetobacter in the intensive care unit

Acinetobacter baumannii, an increasingly common hospital pathogen, is notable for its ability to colonise and infect the more vulnerable among hospital patients. The species also has the capacity to acquire antibiotic resistance determinants and thus restrict antibiotic options. Survival and persistence on inanimate environmental surfaces assists its spread within the hospital. A. baumannii has caused several reported outbreaks in intensive care units, in several of which respiratory support equipment was implicated as a vehicle or reservoir. Aspects of ventilator circuit design provide a potential portal of entry to the patient's lower respiratory tract that A. baumannii is able to exploit. Recognition of these critical microbial entry points, particularly the temperature probe and its socket, may provide a means of curtailing Acinetobacter outbreaks in intensive care patients. [AIC Aust Infect Control 1999; 4(2):8-10]