Anesthesiology and Intensive Care

The Valsalva maneuver or Valsalva manoeuvre is performed by moderately forceful attempted exhalation against a closed airway, usually done by closing one's mouth, pinching one's nose shut while pressing out as if blowing up a balloon. Phase 1. The onset of blowing. The pressure within the chest and abdomen increases and presses upon the arteries in the chest, which results in an increase of mean arterial blood pressure. This activates the baroreceptor reflex, which results in an increase of parasympathetic (vagal) activity and hence in a drop of heart rate. The increased intrathoracic pressure also reduces the amount of blood that comes into the right atrium (decreased venous return or preload). Phase 2. A decrease of venous return results in a lower amount of blood that is ejected from the heart, which results in a decrease of central venous pressure and consequently in a decrease of mean arterial blood pressure. This activates the baroreflex, which results in a...