title: Changes in superior mesenteric artery blood flow after oral, enteral, and parenteral feeding in humans.
abstract: OBJECTIVE
  Alterations in splanchnic blood flow cause gut ischemia and may predispose to gut-derived sepsis. Increases in superior mesenteric artery (SMA) blood flow occur follow the oral ingestion of food, but the effects of enteral nutrition (EN) on splanchnic perfusion are poorly defined and those of parenteral nutrition (PN) are unknown in humans. The aim of this study was to investigate changes in SMA flow in healthy controls and patients receiving adjuvant nutrition.
  
  
  METHODS
  Qualitative before-after study.
  
  
  METHODS
  Intensive care and general wards at Scarborough Hospital, Scarborough, United Kingdom.
  
  
  METHODS
  Fourteen healthy volunteers and 20 consecutive hemodynamically stable patients receiving adjuvant nutrition.
  
  
  METHODS
  Oral, EN, or PN after an overnight fast.
  
  
  RESULTS
  Duplex ultrasonography was used to assess SMA flow after an overnight fast. Subjects were then rescanned 3 hrs later after commencement of the appropriate test feed so that postprandial flows could be determined. Of the 20 patients recruited, 10 were receiving EN (120 kcal) and 10 PN (175 kcal). Of the 14 volunteers, three received no feed before their second scan (controls), six received an oral meal (530 kcal), and five received EN (120 kcal). Changes in SMA flow within groups were assessed. The control (fasting) volunteers showed no change between the two scans (p = 1.000). All subjects fed intraluminally demonstrated significant increases in postprandial SMA blood flow. Conversely, all patients fed parenterally showed decreased postprandial SMA flows with a median (interquartile range) fasting SMA flow of 14.5 (4.8-24.8) mL/sec, which decreased to 6.1 (2.4-9.2) mL/sec postprandially (p = 0.013).
  
  
  CONCLUSIONS
  Splanchnic flow is modulated by the route of feeding. The clinical significance of these findings requires further investigation as they may be important in the management of the critically ill patient, particularly in those with cardiovascular instability or any patient predisposed to gut ischemia.
authors.affiliation: The Combined Gastroenterology Research Unit, Scarborough Hospital, Scarborough, United Kingdom.
authors.forename: Marcel
authors.initials: M
authors.lastname: Gatt
authors.forename: John
authors.initials: J
authors.lastname: MacFie
authors.forename: Alexander D G
authors.initials: AD
authors.lastname: Anderson
authors.forename: Gareth
authors.initials: G
authors.lastname: Howell
authors.forename: Bala S
authors.initials: BS
authors.lastname: Reddy
authors.forename: Aravind
authors.initials: A
authors.lastname: Suppiah
authors.forename: Ian
authors.initials: I
authors.lastname: Renwick
authors.forename: Charles J
authors.initials: CJ
authors.lastname: Mitchell
mesh_terms: D000328:Adult; D000368:Aged; D004435:Eating / Q000502:physiology*; D004750:Enteral Nutrition; D005260:Female; D006801:Humans; D008297:Male; D017538:Mesenteric Artery, Superior / Q000502:physiology* / Q000503:physiopathology; D008875:Middle Aged; D010288:Parenteral Nutrition; D012039:Regional Blood Flow