Freyschuss U, Melcher A
Acta Physiol Scand Suppl. 1976;435:I, 10 pp..
The effect of tidal volume (VT) and of the intrathoracic pressure (Poes) on the respiratory sinus arrhythmia (RSA) was studied in healthy subjects. They breathed into a spirometer with a VT of 1, 1.5, and 2 1, at a standardized, slow respiratory rate, 6-min-1 (A). Poes was varied by (B) adding a negative inspiratory pressure (NIP) of 5 cm of water and by (C) intermittent positive pressure ventilation (IPPV) at identical VT and respiratory frequency. In separate study (D), intermittent negative pressure ventilation (INPV) was induced by applying negative pressure on the thorax. In A, increasing VT provoked an augmented RSA by a more marked tachycardia as well as bradycardia. On increasing the amplitude of Poes in B, RSA was somewhat more marked due to a lower minimum heart rate. Whem comparing respiratory cycles that had similar Poes but a different VT, the larger VT caused a slight increase in the RSA amplitude due to a more marked deceleration of the heart rate. IPPV almost abolished RSA, whereas INPV did not reduce the arrhythmia. It is concluded that pulmonary stretch reflexes to a minor extent contribute to RSA, whereas the hypothesis of a central nervous origin does not gain support. Cardiovascular reflexes remain the main possible cause of RSA.
在健康受试者中研究了潮气量（VT）和胸内压（Poes）对呼吸性窦性心律不齐（RSA）的影响。他们以标准化的慢呼吸频率6次/分钟，分别以1、1.5和2升的潮气量向肺量计中呼吸（A）。通过（B）添加5厘米水柱的负吸气压力（NIP）和（C）在相同潮气量和呼吸频率下进行间歇正压通气（IPPV）来改变胸内压。在另一项研究（D）中，通过对胸部施加负压来诱导间歇负压通气（INPV）。在A中，增加潮气量会通过更明显的心动过速和心动过缓引发增强的呼吸性窦性心律不齐。在B中增加胸内压幅度时，由于最低心率较低，呼吸性窦性心律不齐会更加明显。当比较具有相似胸内压但潮气量不同的呼吸周期时，较大的潮气量由于心率更明显的减速而导致呼吸性窦性心律不齐幅度略有增加。间歇正压通气几乎消除了呼吸性窦性心律不齐，而间歇负压通气并未减轻心律失常。得出的结论是，肺牵张反射在一定程度上对呼吸性窦性心律不齐有影响，而中枢神经起源的假说未得到支持。心血管反射仍然是呼吸性窦性心律不齐的主要可能原因。
