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Position modifies carotid artery blood flow velocity during straining
1School of Nursing, University of Michigan, Ann Arbor 48109.
Research in Nursing & Health
|April 1, 1990
Summary
The Valsalva maneuver (VM) causes significant changes in carotid artery blood flow velocity (CABFV). A seated chair position during VM reduces these hemodynamic shifts, offering potential therapeutic benefits.
Area of Science:
- Neurology
- Cardiovascular Physiology
- Medical Engineering
Background:
- The Valsalva maneuver (VM) induces rapid cerebrovascular blood flow alterations.
- These hemodynamic shifts are linked to aneurysm rupture and rebleeding events.
Purpose of the Study:
- To investigate how different body positions influence the intensity of hemodynamic shifts during the VM.
- To assess the impact of body position on carotid artery blood flow velocity (CABFV) during VM.
Main Methods:
- 141 healthy adults (30-55 years) performed the VM (straining at 40 mmHg for 10 seconds) in five body positions: chair, 70° upright, 30° upright, flat, and side.
- Carotid artery blood flow velocity (CABFV) was continuously monitored using an ultrasonic Doppler technique.
Main Results:
- Body position significantly affected CABFV during VM (F = 13.7; p < .0001).
- The chair position resulted in significantly less reduction and increase in CABFV compared to other positions (p < .05).
- The 70° upright position showed less CABFV fall than 30° upright, flat, and side positions (p < .05).
Conclusions:
- The chair position can be therapeutically employed to mitigate severe cerebrovascular hemodynamic shifts associated with the Valsalva maneuver.
- Understanding positional effects on hemodynamic responses to VM is crucial for managing patients at risk of vascular events.