Introduction We hypothesized that oral leak size, a hitherto unstudied technical variable, would influence hemodynamic responses and difficulty level in executing the Valsalva maneuver (VM).

Methods Based on power analysis, 38 healthy participants were included. Oral leak size in random order was 0.35, 0.71, 1.01,1.40 mm. Level of difficulty was rated 1 to 10, with ≥7-10 being severe.VM was performed at 40 mmHg expiratory strain for 15 seconds. Three trials were averaged for each leak size. Data were analyzed by repeated measures ANOVA and pairwise comparisons with Tukey adjustment, a mixed effect model, and a generalized linear model.

Results Of the 38 participants, 4 were excluded from analysis for protocol deviation. Phase II L mean BP (MBP) was significantly higher with the largest leak versus all others (P

Conclusions Oral leak size affected VM hemodynamic parameters and level of difficulty. Oral leak size exceeding 1.01 mm significantly affected phase II L MBP. Level of difficulty rose with increasing leak size and was significantly correlated with increase in phase II L MBP.