呼吸频率和潮气量对兔心率变异的影响

摘要

Objective To observe the effects of respiratory frequency (RF) and tidal volume (Vt) on components of frequency spectra of rabbits heart rate variability (HRV). Methods The rabbits model of controlled respiratory was established,by which to adjust rabbit respiratory parameters. Holter was used to record ECG and respiratory wave simultaneously under different RF and Vt. We compared the indicators of different RF and Vt, such as the relationship of RR- Interval and respiratory, HRV frequency spectra, the center frequency of respiratory peak, heart rate (HR), total power (TP),very-low frequencies (VLF) ,low frequencies normalized (LF norm), high frequencies normalized (HF norm) and LF/HF ratio (LF/HF). Results ① RR- interval cyclical change coincided with the respiratory cycle. ②RF and Vt could make respiratory peak change[ compared with the rabbits with Basic RF of 50 bpm, 60 bpm would shift to right(P ＜ 0. 01 ),40 bpm would shift to left (P ＜0.01 ) ,at the same time, respiratory peak appeared in LF band ; compared with the Vt of 10ml/kg, the Vt of 8 ml/kg would shift to right( P ＜ 0. 05 ), the Vt of 12 ml/kg did not have great change( P ＞ 0.05 ) ].③Compared with basic RF of 50 bpm,60 bpm increased HF norm( P ＜ 0.05 ) ;40 bpm slowed down HR( P ＜ 0.01 ) and decreased HF norm( P ＜ 0. 05 ) and increased LF norm and LF/HF( P ＜ 0.01 ). ④Compared with the Vt of 10 ml/kg, the Vt of 8 ml/kg slowed down HR(P ＜ 0. 01 ) ,Vt did not affect HRV spectrum components. Conclusion RF affects HRV not only in the HF component, but also in the LF component. Its generation mechanism is respiratory peak shift around the dividing line of LF band and HF band. [ Chinese Journal of Cardiac Pacing and Electrophysiology,2011,25 (3) :258 -262 ]%目的观察呼吸频率(RF)和潮气量(Vt)对心率变异(HRV)频谱成分的影响.方法建立兔机械通气模型,通过呼吸机调节呼吸参数,用Holter同步记录不同RF、Vt的心电和呼吸波形,比较不同RF和Vt的RR间期变化和呼吸的关系、HRV频谱、呼吸峰中心频率、心率(HR)以及总功率(TP)、极低频功率(VLF)、低频标化(LFnorm)、高频标化(HF norm)和LF/HF等频谱成分指标.结果①RR间期周期性变化与呼吸周期吻合.②改变RF和Vt可使HRV呼吸峰发生移位.与RF 50次/分时相比,60次/分时呼吸峰右移(P＜0.01),40次/分时呼吸峰左移(P＜0.01),此时呼吸峰处于LF频段;与Vt 10 ml/kg时相比,8 ml/kg时呼吸峰右移(P＜0.05),12 ml/kg时呼吸峰无显著移位(P＞0.05).③与RF 50次/分相比,60次/分HF norm增大(P＜0.05);40次/分HR减慢(P＜0.01)、HF norm减小(P＜0.05)、LF norm增大和LF/HF增大(P＜0.01).④与Vt 10ml/kg相比,8ml/kg时HR减慢(P＜0.01),Vt对HRV频谱成分无显著影响(P＞0.05).结论RF不仅影响HF成分,而且还影响LF成分,其影响机制与呼吸峰移位跨过LF频段与HF频段分界点有关.