Study of Nutrition in Acute Pancreatitis

1. Patients over the age of 18yr
2. The typical history of abdominal pain for over 24h with raised (>3-fold) serum pancreatic enzymes on admission

3. Severe pancreatitis, as defined by: the Atlanta classification of severe disease (60), but with important modifications to sharpen the definition of severity, to include one or more of the following:

   1. The presence of organ failure (MOF) resistant to early aggressive IV fluid resuscitation as defined by a Marshall score of ≥2 in any one organ (for calculation, see Appendix (61)), excluding the liver component as the abnormality may be due to gall stones rather than the systemic inflammatory response (17)
   2. Pancreatic necrosis >30% on CT scan or a modified CT severity index (CTSI: see Appendix (62)) of ≥8
   3. APACHE score ≥ 8 (for calculation, see Appendix (63))
   4. Ranson's criteria ≥3 (for calculation, see Appendix (64))

Exclusion Criteria:

1. Inability to absorb enteral nutrients resulting in chronic intestinal failure and need for IV feeding, such as short bowel, malabsorption disorders such as celiac or intestinal proliferative disorders, chronic obstruction and pseudo-obstruction.
2. Time elapse since commencement of acute pancreatitis symptoms >10 days. In order to take advantage of the 'window of opportunity' to prevent the progression of 'transient' MOF to 'permanent' MOF, patients should be started on enteral feeding as soon as possible. However, in practice many patients present initially with mild disease which progresses to severe necrosis at the end of the first week, and these patients need nutritional support for long periods of time. Consequently, this is an important group to include in this investigation. Post hoc analysis will be performed to see whether they behave differently to patients fed earlier in their disease
3. Any form of artificial feeding since commencement of acute pancreatitis symptoms
4. Patients with chronic pancreatitis and pancreatic insufficiency requiring pancreatic enzyme supplements, based on clinical history and specific investigations such as by ERCP, MRP, or CT scanning.
5. Pre-existing chronic renal insufficiency requiring hemodialysis or peritoneal dialysis, as this will make assessment of severity difficult
6. Pre-existing end-stage liver disease with ascites, coagulopathy and encephalopathy, supported by biopsy, and/or radiological imaging and endoscopy (portal hypertension, varices and gastropathy), as this will make assessment of severity difficult
7. Chronic immunodeficiency states such as AIDS defined by CD-4 count \< 50, and immunoglobulin deficiencies as it may independently affect feeding tolerance and infection risk
8. Pancreatic cancer proven by biopsy, and any other form of cancer with life-expectancy \<6 months.
9. Current somatostatin or corticosteroid therapy as these drugs will impair intestinal, metabolic, and immune function, and therefore affect absorption and infection risk.
10. Contraindication to using the nose for enteral tube insertion
11. Severe traumatic brain injury with ICP>20mmHg despite treatment
12. Previous completion or withdrawal from this study