Próba Valsavy zwiększa czułość składowej przywspółczulnej odruchu spowodowanego odbarczeniem baroreceptorów u młodych zdrowych osób

Abstract

Introduction. The objective was to verify the hypothesis that change in cardiovagal baroreceptor unload reflex sensitivity occurs between early phase 2 (VM2E) and phase 3 (VM3) of the Valsalva manoeuvre (VM). The study was performed on 29 volunteers between the ages of 25 and 40 (29.3 ± SE 4.0). Material and methods. The experimental scheme was as follows: rest in sitting position, VM in sitting position maintaining an expiratory pressure of 20 mm Hg for 15 seconds, rest in sitting position. Changes in systolic blood pressure (SBP), diastolic blood pressure (DBP) and heart rate (HR) were measured using Finapres. Results. In VM2E and VM3, HR increased (+51.76 ± SE 4.06 beats/min., p < 0.001; +37.77 ± SE 8.65 beats/min., p < 0.0001, respectively) in response to a fall in SBP (–47.55 ± SE 3.95 mmHg, p < 0.001; –29.66 ± SE 2.80 mmHg, p < 0.0001; respectively). Both events of baroreceptor unload have been observed within the very similar range of SBP and HR. Conclusion. The slope of regression relating change in heart rate (DHR) and systolic arterial pressure (DSBP) was significantly higher in VM3 (DHR2 = –1.063 × DSBP2 + 7.0986) than in VM2E (DHR1 = –0.4395 × DSBP2 + 30.862), suggesting the increased baroreceptors’ sensitivity toward SBP fall in VM3 compared to VM2E. VM increases vagal baroreceptor unloads reflex sensitivity.