title: Effects of gastric distension on blood pressure and superior mesenteric artery blood flow responses to intraduodenal glucose in healthy older subjects.
abstract: Postprandial hypotension occurs frequently and is associated with increased morbidity. Gastric distension may attenuate the postprandial fall in blood pressure (BP). Using a barostat, we sought to determine the effects of gastric distension on BP, heart rate (HR), and superior mesenteric artery (SMA) blood flow responses to intraduodenal glucose in eight (6 men, 2 women) healthy older (65-75 yr old) subjects. BP and HR were measured using an automated device and SMA blood flow was measured using Doppler ultrasound on 4 days in random order. SMA blood flow was calculated using the radius of the SMA and time-averaged mean velocity. Subjects were intubated with a nasoduodenal catheter incorporating a duodenal infusion port. On 2 of the 4 days, they were intubated orally with a second catheter, incorporating a barostat bag, positioned in the fundus and set at 8 mmHg above minimal distending pressure. Each subject received a 60-min (0-60 min) intraduodenal infusion of glucose (3 kcal/min) or saline (0.9%); therefore, the four study conditions were as follows: intraduodenal glucose + barostat (glucose + distension), intraduodenal saline + barostat (saline + distension), intraduodenal glucose (glucose), and intraduodenal saline (saline). Systolic and diastolic BP fell during glucose compared with saline (P = 0.05 and P = 0.003, respectively) and glucose + distension (P = 0.01 and P = 0.05, respectively) and increased during saline + distension compared with saline (P = 0.04 and P = 0.006, respectively). The maximum changes in systolic BP were -14 +/- 5, +11 +/- 2, -3 +/- 4, and +15 +/- 3 mmHg for glucose, saline, glucose + distension, and saline + distension, respectively. There was an increase in HR during glucose and glucose + distension (maximum rise = 14 +/- 2 and 14 +/- 3 beats/min, respectively), but not during saline or saline + distension. SMA blood flow increased during glucose and glucose + distension (2,388 +/- 365 and 1,673 +/- 187 ml/min, respectively), but not during saline, and tended to decrease during saline + distension (821 +/- 115 and 864 +/- 116 ml/min, respectively). In conclusion, gastric distension has the capacity to abolish the fall in BP and attenuate the rise in SMA blood flow induced by intraduodenal glucose in healthy older subjects.
authors.affiliation: University of Adelaide, Discipline of Medicine, Royal Adelaide Hospital, North Terrace, Adelaide, SA 5000, Australia.
authors.forename: Lora
authors.initials: L
authors.lastname: Vanis
authors.forename: Diana
authors.initials: D
authors.lastname: Gentilcore
authors.forename: Trygve
authors.initials: T
authors.lastname: Hausken
authors.forename: Amelia N
authors.initials: AN
authors.lastname: Pilichiewicz
authors.forename: Kylie
authors.initials: K
authors.lastname: Lange
authors.forename: Christopher K
authors.initials: CK
authors.lastname: Rayner
authors.forename: Christine
authors.initials: C
authors.lastname: Feinle-Bisset
authors.forename: James H
authors.initials: JH
authors.lastname: Meyer
authors.forename: Michael
authors.initials: M
authors.lastname: Horowitz
authors.forename: Karen L
authors.initials: KL
authors.lastname: Jones
mesh_terms: D000368:Aged; D001783:Blood Flow Velocity; D001794:Blood Pressure / Q000187:drug effects / Q000502:physiology*; D004386:Duodenum / Q000502:physiology; D005260:Female; D005947:Glucose / Q000494:pharmacology*; D006339:Heart Rate / Q000502:physiology; D006801:Humans; D008297:Male; D017538:Mesenteric Artery, Superior / Q000502:physiology*; D011312:Pressure; D013270:Stomach / Q000502:physiology*; D013549:Sweetening Agents / Q000494:pharmacology
chemical_list: D013549:Sweetening Agents; D005947:Glucose