Effects of Oral Leak Size on Valsalva Responses.

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 s. 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 < 0.001). TL was significantly lower with the largest leak versus all others (P = 0.0029). Difficulty performing the VM increased significantly with every increase in leak size (P < 0.001), and a significantly higher percentage of participants reported severe difficulty with leak 4 compared with leak 1 (P < 0.001), 2 (P = 0.0068), and 3 (P = 0.0068). There was no significant effect of phase II E SBP decline on phase II L MBP increase (P = 0.0752). Difficulty increased significantly with one unit increase in phase II L MBP (P = 0.0002). 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.