Antro-pyloro-duodenal motor responses to gastric and duodenal nutrient in critically ill patients.
BACKGROUND
Gastric emptying is frequently delayed in critical illness which compromises the success of nasogastric nutrition. The underlying motor dysfunctions are poorly defined.


OBJECTIVE
To characterise antro-pyloro-duodenal motility during fasting, and in response to gastric and duodenal nutrient, as well as to evaluate the relationship between gastric emptying and motility, in the critically ill.


METHODS
Fifteen mechanically ventilated patients from a mixed intensive care unit; 10 healthy volunteers.


METHODS
Antro-pyloro-duodenal pressures were recorded during fasting, after intragastric administration (100 ml; 100 kcal), and during small intestinal infusion of liquid nutrient (6 hours; 1 kcal/min). Gastric emptying was measured using a (13)C octanoate breath test.


RESULTS
In healthy subjects, neither gastric nor small intestinal nutrient affected antro-pyloro-duodenal pressures. In patients, duodenal nutrient infusion reduced antral activity compared with both fasting and healthy subjects (0.03 (0-2.47) waves/min v 0.14 (0-2.2) fasting (p = 0.016); and v 0.33 (0-2.57)/min in healthy subjects (p = 0.005)). Basal pyloric pressure and the frequency of phasic pyloric pressure waves were increased in patients during duodenal nutrient infusion (3.12 (1.06) mm Hg; 0.98 (0.13)/min) compared with healthy subjects (-0.44 (1.25) mm Hg; p<0.02 after 120 minutes; 0.29 (0.15)/min; p = 0.0002) and with fasting (-0.06 (1.05) mm Hg; p<0.03 after 160 minutes; 0.49 (0.13)/min; (p = 0.0001). Gastric emptying was delayed in patients (gastric emptying coefficient 2.99 (0.2) v 3.47 (0.1); p = 0.015) and inversely related to the number of pyloric pressure waves (r = -0.563, p = 0.029).


CONCLUSIONS
Stimulation of pyloric and suppression of antral pressures by duodenal nutrient are enhanced in the critically ill and related to decreased gastric emptying.
Chapman
M
M
Intensive Care Unit, Royal Adelaide Hospital, North Terrace, Adelaide, Australia. mchapman@mail.rah.sa.gov.au
Fraser
R
R
Vozzo
R
R
Bryant
L
L
Tam
W
W
Nguyen
N
N
Zacharakis
B
B
Butler
R
R
Davidson
G
G
Horowitz
M
M
D000328:Adult; D000368:Aged; D016638:Critical Illness; D004386:Duodenum / Q000503:physiopathology; D004750:Enteral Nutrition / Q000379:methods*; D005260:Female; D005746:Gastric Emptying / Q000502:physiology; D005769:Gastrointestinal Motility / Q000502:physiology*; D006801:Humans; D008297:Male; D008875:Middle Aged; D011312:Pressure; D011706:Pyloric Antrum / Q000503:physiopathology; D011708:Pylorus / Q000503:physiopathology; D012121:Respiration, Artificial / Q000379:methods