Hughes P D, Polkey M I, Harrus M L, Coats A J, Moxham J, Green M
Department of Cardiology and Respiratory Muscle Laboratory, Royal Brompton Hospital and National Heart and Lung Institute, London, UK.
Am J Respir Crit Care Med. 1999 Aug;160(2):529-34. doi: 10.1164/ajrccm.160.2.9810081.
Reduced respiratory muscle strength has been reported in chronic heart failure (CHF) in several studies. The data supporting this conclusion come almost exclusively from static inspiratory and expiratory mouth pressure maneuvers (MIP, MEP), which many subjects find difficult to perform. We therefore performed a study using measurements that are less dependent on patient aptitude and also provide specific data on diaphragm strength. In 20 male patients and 15 control subjects we measured MIP and MEP as well as esophageal and transdiaphragmatic pressure during maximal sniffs (Sn Pes, Sn Pdi) and cervical magnetic phrenic nerve stimulation (Tw Pdi). In a subgroup the response to paired phrenic nerve stimulation (pTw Pdi) at interpulse intervals from 10 to 200 ms (5 to 100 Hz) was also determined. As expected, MIP was significantly reduced in the CHF group (CHF, 69.5 cm H(2)O; control, 96.7 cm H(2)O; p = 0.01), but differences were much less marked for Sn Pes (CHF, 95.2 cm H(2)O; control, 104.8 cm H(2)O; p = 0.20) and MEP (CHF, 109.1 cm H(2)O; control, 135.7 cm H(2)O; p = 0.09). Diaphragm strength was significantly reduced (Sn Pdi: CHF, 123.8 cm H(2)O; control 143.5 cm H(2)O; p = 0.04. Tw Pdi: CHF, 21.4 cm H(2)O; control, 28.5 cm H(2)O; p = 0.0005). Paired phrenic nerve stimulation suggested a trend to increased twitch summation at 5 to 20 Hz in CHF, although this did not reach significance. We conclude that mild reduction in diaphragm strength occurs in CHF, possibly because of an increased proportion of slow fibers, but overall strength of the respiratory muscles remains well preserved.
多项研究报告称，慢性心力衰竭（CHF）患者的呼吸肌力量会减弱。支持这一结论的数据几乎完全来自静态吸气和呼气口压动作（MIP、MEP），但许多受试者觉得这些动作很难完成。因此，我们开展了一项研究，采用的测量方法对患者能力的依赖性较小，并且还能提供有关膈肌力量的具体数据。我们对20名男性患者和15名对照受试者测量了MIP和MEP，以及最大吸气时的食管压力和跨膈肌压力（Sn Pes、Sn Pdi）和颈部膈神经磁刺激（Tw Pdi）。在一个亚组中，还测定了在10至200毫秒（5至100赫兹）的脉冲间隔下对成对膈神经刺激（pTw Pdi）的反应。正如预期的那样，CHF组的MIP显著降低（CHF为69.5厘米水柱；对照组为96.7厘米水柱；p = 0.01），但Sn Pes（CHF为95.2厘米水柱；对照组为104.8厘米水柱；p = 0.20）和MEP（CHF为109.1厘米水柱；对照组为135.7厘米水柱；p = 0.09）的差异则不太明显。膈肌力量显著降低（Sn Pdi：CHF为123.8厘米水柱；对照组为143.5厘米水柱；p = 0.04。Tw Pdi：CHF为21.4厘米水柱；对照组为28.5厘米水柱；p = 0.0005）。成对膈神经刺激表明，CHF患者在5至20赫兹时有抽搐总和增加的趋势，尽管这一趋势未达到显著水平。我们得出结论，CHF患者的膈肌力量会出现轻度下降，可能是因为慢肌纤维比例增加，但呼吸肌的整体力量仍保持良好。
