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Continuous positive-pressure ventilation and choledochoduodenal flow resistance
Journal of Applied Physiology
|December 1, 1975
Summary
Continuous positive-pressure ventilation (CPPV) significantly increases resistance to bile flow through the choledochoduodenal junction in dogs, likely due to vascular engorgement. This effect can be reversed and reduced by certain medications.
Area of Science:
- Physiology
- Gastroenterology
Background:
- The choledochoduodenal junction regulates bile flow.
- Positive-pressure ventilation is commonly used in critical care settings.
Purpose of the Study:
- To investigate the impact of continuous positive-pressure ventilation (CPPV) on resistance to bile flow through the choledochoduodenal junction.
- To compare CPPV with intermittent positive-pressure ventilation (IPPV).
Main Methods:
- Resistance was measured during constant saline perfusion in dogs.
- Eight dogs were ventilated with IPPV and CPPV, with fluid adjustments to maintain hematocrit or arterial pressure.
- Four additional dogs received vasopressors or phenylephrine during CPPV.
Main Results:
- CPPV increased common bile duct pressure and choledochoduodenal resistance by 21-30% compared to IPPV.
- These changes reversed upon return to IPPV.
- Intravenous vasopressin, norepinephrine, and intraductal phenylephrine reduced choledochoduodenal resistance during CPPV.
Conclusions:
- CPPV increases resistance to bile flow at the choledochoduodenal junction.
- Vascular engorgement is the likely mechanism.
- Pharmacological agents may mitigate this effect.