Abstract
Our objectives were to characterize colonic viscoelastic properties of the human descending colon by assessing pressure-volume (P-V) relationships during barostatic balloon distension. In 16 healthy subjects, a balloon was inflated to 44 mmHg and then deflated to 0 mmHg in 4-mmHg steps at 10, 30, and 60 ml/min, allowing volume fluctuations to stabilize at each pressure increment. Thereafter, these "quasi-static" P-V curves were compared with "dynamic" distensions to 300 ml, at 1 and 10 ml/s, before and after intravenous atropine in another five subjects. During quasi-static curves, balloon volume stabilized at each pressure increment. Quasi-static P-V curves were reproducible within individuals and approximated to a power exponential function and revealed hysteresis, indicative of viscoelasticity. Body mass index influenced quasi-static P-V curves during inflation but not during deflation. The colon was less compliant during dynamic distensions at 10 ml/s than during quasistatic distensions. Atropine increased quasi-static compliance and attenuated differences between quasi-static and rapid distensions. We conclude that colonic viscoelastic properties can be assessed by quasi-static P-V curves. Rapid colonic distension activated neural reflexes, thereby reducing colonic compliance compared with quasi-static distensions.
Original language | English (US) |
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Pages (from-to) | G459-G466 |
Journal | American Journal of Physiology - Gastrointestinal and Liver Physiology |
Volume | 281 |
Issue number | 2 44-2 |
DOIs | |
State | Published - 2001 |
Keywords
- Atropine
- Body mass index
- Compliance
- Hysteresis
- Pressure-volume relationships
ASJC Scopus subject areas
- Physiology
- Hepatology
- Gastroenterology
- Physiology (medical)