['The Safe guide is a central venous puncture needle that serves as both a pilot needle and as an introducer. A guide wire can be inserted into a vein through the side port at the hub of the 22-gauge Safe guides needle initially inserted as a pilot needle. However, guide wire insertion may fail due to kinking or locking at the side port. Increasing airway pressure to 20 cm H2O by squeezing a respiratory bag during insertion of the guide wire together with venous puncture was attempted to determine if would decrease guide wire trouble.', 'A total of 120 patients scheduled for central venous catheterization by right internal jugular puncture were divided into two groups. Patients in group-A (n = 60) were catheterized by the conventional method and those in group-B (n = 60) were catheterized by applying the Valsalva maneuver. Three observations were made: 1) Frequency of cases in which blood back-flow occurred during withdrawal only and not upon advancement of the puncture needle. 2) Frequency of cases in which kinking and/or locking of the guide wire occurred at the hub during its insertion. And 3) the occurrence of complications.', '1) The patency of the vein was preserved and blood back-flow was obtained during advancement of the puncture needle in all cases in which the Valsalva maneuver was applied. 2) The incidence of kinking and/or locking during insertion of the guide wire decreased from 16.7% to 3.4% by applying positive airway pressure during the Valsalva maneuver. And 3) complications were negligible. Additionally, the application of the Valsalva maneuver allowed successful guide wire insertion in 6 out of 9 cases (67%) in group-A, in which the initial attempt using the conventional method had failed.'] Does valsalva maneuver prevent guide wire trouble associated with 22-gauge safe guide?