Lipid-associated total parenteral nutrition in patients with severe acute pancreatitis

Acute Pancreatitis: Work-up and Management

Acute pancreatitis is still a common clinical entity that causes significant morbidity and mortality. The most common etiological associations include chronic al coholism, biliary tract disease, iatrogenic (e.g., endo scopic retrograde cholangiopancreatography-induced), hypertriglyceridemia, and idiopathic varieties. New radiological techniques such as dynamic pancreatog raphy appear to be useful in diagnosing and determin ing the extent of necrotizing pancreatitis. Biochem ical variables such as the C-reactive protein and the trypsinogen-activated peptide seem promising in de tecting severe disease within the first few days of hospi talization. Computed tomographic-guided percutane ous aspiration of phlegmonous pancreatitis may be helpful in differentiating infected from noninfected masses. Although current studies have not identified any pharmacological agent as efficacious in improving sur vival, emergency sphincterotomy and removal of im pacted gallstones in severe gallstone pancreatitis may be beneficial in this regard. Prolonged (i.e., 7 day) perito neal dialysis may reduce the severity of pancreatic sep sis. Surgical drainage of infected fluid collections such as abscesses is a well-accepted adjunct to medical therapy. Surgical necrosectomy for necrotizing pancreatitis, however, which is advocated in some aggressive surgi cal units, is not yet commonplace and its role needs to be determined in controlled studies.

Potential influence of intravenous lipids on the outcomes of acute pancreatitis

Parenteral nutrition (PN) has been associated with a higher rate of adverse outcomes compared with enteral feeding in patients with acute pancreatitis (AP). However, PN may be necessary when feeding via the enteral route is poorly tolerated or impossible, and PN is recommended as a second-line nutrition therapy in AP. Intravenous (IV) lipids are commonly used as a part of PN in patients with AP. While the adverse outcomes related to the use of PN in AP have commonly been attributed to infectious complications, data suggest that the unsaturated fatty acids in the triglycerides used in IV lipids may contribute to the development of organ failure. We discuss the clinical and experimental data on this issue and the alternative lipid emulsions that are being studied.

Nutritional support in acute and chronic pancreatitis

Nutritional support can have a significant beneficial impact on the course of moderate to severe acute pancreatitis. Enteral nutrition is preferred, with emphasis on establishment of jejunal access; however, parenteral nutrition can also be of value if intestinal failure is present. Early initiation of nutritional support is critical, with benefits decreasing rapidly if begun after 48 hours from admission. Severe malnutrition in chronic pancreatitis can be avoided or treated with dietary modifications or enteral nutrition.

Enteral versus parenteral nutrition for acute pancreatitis

BACKGROUND

Acute pancreatitis creates a catabolic stress state promoting a systemic inflammatory response and nutritional deterioration. Adequate supply of nutrients plays an important role in recovery. Total parenteral nutrition (TPN) has been standard practice for providing exogenous nutrients to patients with severe acute pancreatitis. However, recent data suggest that enteral nutrition (EN) is not only feasible, but safer and more effective.Therefore, we sought to update our systematic review to re-evaluate the level of evidence.

OBJECTIVES

To compare the effect of TPN versus EN on mortality, morbidity and length of hospital stay in patients with acute pancreatitis.

SEARCH STRATEGY

Trials were identified by computerized searches of The Cochrane Controlled Trials Register, MEDLINE, and EMBASE. Additional studies were identified by searching Scisearch, bibliographies of review articles and identified trials. The search was undertaken in August 2000 and updated in September 2002, October 2003, November 2004 and November 2008. No language restrictions were applied.

SELECTION CRITERIA

Randomized clinical trials comparing TPN to EN in patients with acute pancreatitis.

DATA COLLECTION AND ANALYSIS

Two reviewers independently abstracted data and assessed trial quality. A standardized form was used to extract relevant data.

MAIN RESULTS

Eight trials with a total of 348 participants were included. Comparing EN to TPN for acute pancreatitis, the relative risk (RR) for death was 0.50 (95% CI 0.28 to 0.91), for multiple organ failure (MOF) was 0.55 (95% CI 0.37 to 0.81), for systemic infection was 0.39 (95% CI 0.23 to 0.65), for operative interventions was 0.44 (95% CI 0.29 to 0.67), for local septic complications was 0.74 (95% CI 0.40 to 1.35), and for other local complications was 0.70 (95% CI 0.43 to 1.13). Mean length of hospital stay was reduced by 2.37 days in EN vs TPN groups (95% CI -7.18 to 2.44). Furthermore, a subgroup analysis for EN vs TPN in patients with severe acute pancreatitis showed a RR for death of 0.18 (95% CI 0.06 to 0.58) and a RR for MOF of 0.46 (95% CI 0.16 to 1.29).

AUTHORS' CONCLUSIONS

In patients with acute pancreatitis, enteral nutrition significantly reduced mortality, multiple organ failure, systemic infections, and the need for operative interventions compared to those who received TPN. In addition, there was a trend towards a reduction in length of hospital stay. These data suggest that EN should be considered the standard of care for patients with acute pancreatitis requiring nutritional support.

Pancreatitis

In the past decade, our understanding of the genetic basis, pathogenesis, and natural history of pancreatitis has grown strikingly. In severe acute pancreatitis, intensive medical support and non-surgical intervention for complications keeps patients alive; surgical drainage (necrosectomy) is reserved for patients with infected necrosis for whom supportive measures have failed. Enteral feeding has largely replaced the parenteral route; controversy remains with respect to use of prophylactic antibiotics. Although gene therapy for chronic pancreatitis is years away, our understanding of the roles of gene mutations in hereditary and sporadic pancreatitis offers tantalising clues about the disorder's pathogenesis. The division between acute and chronic pancreatitis has always been blurred: now, genetics of the disorder suggest a continuous range of disease rather than two separate entities. With recognition of pancreatic intraepithelial neoplasia, we see that chronic pancreatitis is a premalignant disorder in some patients. Magnetic resonance cholangiopancreatography and endoscopic ultrasound are destined to replace endoscopic retrograde cholangiopancreatography for many diagnostic indications in pancreatic disease.

Management of severe acute pancreatitis

BACKGROUND

Acute pancreatitis is still associated with significant morbidity and mortality. Current management guidelines are sometimes equivocal, particularly in relation to the surgical treatment of severe disease. This review assesses available investigative and treatment strategies to allow the development of a formalized management approach.

METHODS

A literature review of diagnosis, staging and management of acute pancreatitis was performed.

RESULTS AND CONCLUSION

Recent evidence has helped to clarify the roles of computed tomography, endoscopic retrograde cholangiopancreatography, prophylactic antibiotics, enteral feeding and fine-needle aspiration for bacteriology in the management of acute pancreatitis. Despite a relative shortage of prospective randomized trials there has been a significant change in the surgical management of acute pancreatitis over the past 20 years. This change has been away from early aggressive surgical intervention towards more conservative management, except when infected necrosis is confirmed. A formalized approach, with appropriate use of the various non-surgical and surgical options, is feasible in the management of severe acute pancreatitis.

Enteral versus parenteral nutrition for acute pancreatitis

BACKGROUND

Acute pancreatitis creates a catabolic stress state promoting a systemic inflammatory response and nutritional deterioration. Adequate supply of nutrients plays an important role to ensure optimum recovery. Total parenteral nutrition (TPN) has been the standard practice for providing exogenous nutrients to patients with severe acute pancreatitis. However, recent data suggest that enteral nutrition (EN) is feasible. Thus, a comparison of EN and TPN in patients with acute pancreatitis needs to be made.

OBJECTIVES

To compare the effect of total parenteral nutrition (TPN) versus enteral nutrition (EN) on mortality, morbidity and length of hospital stay in patient with acute pancreatitis.

SEARCH STRATEGY

Trials were identified by computerized searches of The Cochrane Controlled Trials Register, MEDLINE, and EMBASE. Additional studies were identified and included where relevant by searching Scisearch, the bibliographies of review articles and identified trials, and personal files. The search was undertaken in August, 2000 and updated in September 2002. No language restrictions were applied.

SELECTION CRITERIA

Randomized clinical trials, in which nutrition support with TPN were compared to EN in patients with acute pancreatitis.

DATA COLLECTION AND ANALYSIS

Two reviewers independently abstracted data and assessed trial quality. Information was collected on death, length of hospital stay, systemic infection, local septic complications, and other local complications.

MAIN RESULTS

Two trials with a total of 70 participants were included. The relative risk (RR) for death with EN vs TPN was 0.56 (95% CI 0.05 to 5.62). Mean length of hospital stay was reduced with EN (WMD -2.20, 95% CI -3.62 to -0.78). RR for systemic infection with EN vs TPN was 0.61 (95% CI 0.29 to 1.28). In one trial, RR for local septic complications and other local complications with EN vs TPN was 0.56 (95% CI 0.12 to 2.68) and 0.16 (95% CI 0.01 to 2.86) respectively.

REVIEWER'S CONCLUSIONS

Although there is a trend towards reductions in the adverse outcomes of acute pancreatitis after administration of EN, clearly there are insufficient data to draw firm conclusions about the effectiveness and safety of EN versus TPN. Further trials are required with sufficient size to account for clinical heterogeneity and to measure all relevant outcomes.

Nutritional management of acute pancreatitis

Most patients with acute pancreatitis have mild to moderate disease and require no specialized nutritional support. Twenty percent to 30% have severe cases, resulting in a catabolic hypermetabolic state, and these patients may require early aggressive nutritional support. Traditionally, this support has been in the form of total parenteral nutrition. However, recent data suggest that enteral nutrition infused into the jejunum is feasible, well tolerated, associated with fewer complications, and significantly less expensive than parenteral nutrition. The pathophysiology of gut function in acute pancreatitis and the rationale and evidence for parenteral and enteral nutritional support are reviewed herein. An algorithm on the nutritional management of acute pancreatitis is suggested.

Evolution of nutritional support in acute pancreatitis

BACKGROUND

Acute pancreatitis is a catabolic illness and patients with the severe form have high metabolic and nutrient demands. Artificial nutritional support should therefore be a logical component of treatment. This review examines the evidence in favour of initiating nutritional support in these patients and the effects of such support on the course of the disease.

METHODS

Medline and Science Citation Index searches were performed to locate English language publications on nutritional support in acute pancreatitis in the 25 years preceding December 1999. Manual cross-referencing was also carried out. Letters, editorials, older review articles and most case reports were excluded.

RESULTS AND CONCLUSION

There is no evidence that nutritional support in acute pancreatitis affects the underlying disease process, but it may prevent the associated undernutrition and starvation, supporting the patient while the disease continues and until normal and sufficient eating can be resumed. The safety and feasibility of enteral nutrition in acute pancreatitis have been established; enteral nutrition may even be superior to parenteral nutrition. Some patients, however, cannot tolerate enteral feeding and this route may not be practical in others. Parenteral nutrition still has a role, either on its own or in combination with the oral and enteral routes, depending on the stage of the illness and the clinical situation.

Nutritional management in acute and chronic pancreatitis

Patients with severe pancreatitis, characterized by multiple organ failure and pancreatic necrosis on CT scan (identified by an Acute Physiology and Chronic Health Evaluation II score of > or = 10 with > or = 3 Ranson criteria), most likely require aggressive nutritional support. Use of the enteral route of feeding may help contain the hypermetabolic stress response, reduce morphologic change and atrophy of the gut, and theoretically decrease late complications of nosocomial infection and organ failure. Evidence that decreasing degrees of stimulation of the pancreas occur as the site of feeding descends in the gastrointestinal tract and evidence from perspective, randomized trials suggest that jejunal feeding appears at least as safe and well tolerated as total parenteral nutrition in acute pancreatitis.

Enteral nutrition is superior to parenteral nutrition in severe acute pancreatitis: results of a randomized prospective trial

BACKGROUND

Parenteral nutrition is well established for providing nutritional support in acute pancreatitis while avoiding pancreatic stimulation. However, it is associated with complications and high cost. Benefits of enteral feeding in other disease states prompted a comparison of early enteral feeding with total parenteral nutrition in this clinical setting.

METHODS

Thirty-eight patients with acute severe pancreatitis were randomized into two groups. The first (n = 18) received enteral nutrition through a nasoenteric tube with a semi-elemental diet, while the second group (n = 20) received parenteral nutrition through a central venous catheter. Safety was assessed by clinical course of disease, laboratory findings and incidence of complications. Efficacy was determined by nitrogen balance. The cost of nutritional support was calculated.

RESULTS

Enteral feeding was well tolerated without adverse effects on the course of the disease. Patients who received enteral feeding experienced fewer total complications (P < 0.05) and were at lower risk of developing septic complications (P < 0.01) than those receiving parenteral nutrition. The cost of nutritional support was three times higher in patients who received parenteral nutrition.

CONCLUSION

This study suggests that early enteral nutrition should be used preferentially in patients with severe acute pancreatitis.

Nutrition support in pancreatitis

Nutrition support in patients with pancreatitis has created a challenge for clinicians. Because the pancreas is normally stimulated by the ingestion of food, particularly fat, patients are often denied oral nutrition. This reduction in the ingestion of food, together with the increased metabolic demands of this disease, often results in a negative energy balance and occasionally undernutrition or malnutrition. This review summarizes the etiologies and methods for staging pancreatitis, the physiology of pancreatic exocrine secretion and the response of the pancreas to different methods of nutrition support. The results of clinical trials, which examine both parenteral and enteral nutrition in animals and humans with this disease, are reviewed. Recommendations for nutrition management of patients with acute and chronic pancreatitis and areas for future research are discussed.

A retrospective study of the use of total parenteral nutrition in dogs and cats

The records of all dogs and cats receiving total parenteral nutrition (TPN) over a 43-month period were examined retrospectively. Dextrose, amino acids, lipids, electrolytes, and vitamins were administered by central venous catheter according to published nutrient recommendations; 72 dogs and 12 cats were studied, accounting for 380 patient days of TPN. Duration of TPN administration was 1-14 days with a mean of 4.5 days. Most animals required TPN because of gastrointestinal dysfunction, and more than half of them gained weight during TPN administration. Mechanical complications were frequent. Metabolic complications, especially lipid and glucose intolerance, were also commonly seen. Septic complications were the least frequently encountered, but resulted in patient morbidity and may have contributed to mortality. Most animals receiving TPN were returned to enteral nutrition and discharged. For critically ill animals unable to tolerate enteral alimentation, TPN can be supportive therapy in the treatment of the primary disease.

Nutritional management of acute and chronic pancreatitis

Acute pancreatitis often results in a catabolic state characterized by profound hemodynamic, metabolic, cardiovascular, pulmonary, hematologic, and renal aberrations. Parenteral nutrition and metabolic support are essential if morbidity and mortality are to be minimized. In chronic pancreatitis, nutritional management ranges from fundamental dietary manipulation with or without administration of appropriate digestive enzymes to enteral supplementation with modular chemically defined diets to total parenteral nutrition, depending on the stage, severity, and manifestations of the disease. In prescribing nutrient substrates in both acute and chronic pancreatitis, consideration must be given to their effects on pancreatic enzyme secretion if optimal results are to be achieved.

Nutritional support in surgical practice: Part II

On admission, a group of high-risk patients who are potential candidates for surgery can be identified, in whom prompt initiation of preoperative enteral or parenteral nutrition may reduce postoperative morbidity and mortality irrespective of the nutritional status. Among these are patients with inflammatory bowel disease, gastrointestinal fistulas, and pancreatitis. Substantial nutritional support has little or no direct effect upon the pathogenesis of the disease, but the discontinuance of oral intake may well have a beneficial effect on the basic disease process. Thus, the provision of enteral or parenteral nutrition gives the patient an optimal opportunity to marshal host defenses in support of healing. In organ system failures, e.g., acute renal failure, liver failure, and pulmonary failure, appropriate nutritional support may assist the patient in coping with the abnormal intermediary metabolism resulting from such failure until satisfactory organ system function returns. From this review, it seems reasonably clear that the initially malnourished patient is less able to successfully withstand the adverse effects of vigorous therapy and/or severe illness than is the well-nourished individual. Hence, correction of malnutrition, either before initiating therapy or concomitant with the treatment, is very likely to be beneficial.