This study is designed to evaluate the various physiologic maneuvers (Valsalva, humming,
breath-hold) for the potential prevention of air embolism during central venous catheter
placement. Central venous pressure measurements were prospectively obtained in 40
patients undergoing central venous catheter placement. The average central venous
pressure at baseline was 3.275 mm Hg (range=− 4 to 16, SD= 5.99). The average central
venous pressure during breath hold was 6.1 mm Hg (range=− 6 to 24, SD= 7.99). The …