Valsalva Maneuver

Question 1

Phase 1

Answer 1

Increased thoracic pressure squeezes blood out of large veins to transiently increase preload

Question 2

Phase 2 (late strain phase)

Answer 2

Continued increased thoracic pressure decreases venous return, dec. SV, dec CO, dec BP, inc.symp/dec.parasymp, inc. HR, contractility, TPR, dec capacitance of veins…maintain BP near normal

Question 3

Phase 3

Answer 3

Rapid release and decreased thoracic pressure causes expansion of blood pulmonary blood vessels causing a transient drop in preload and transient drop in BP (maybe a few heartbeats before blood returning from body gets through lungs and to left ventricle)

Question 4

Phase 4

Answer 4

• Release phase; large venous return to cardiovascular system with high sympathetic tone)
• Continued decreased thoracic pressure results in large increase in venous return to left ventricle, increased preload, increased SV, increased CO, increased BP triggering a dramatic dec.symp/inc.parasymp