Gas exchange during separate diaphragm and intercostal muscle breathing
Gas exchange during separate diaphragm and intercostal muscle breathing
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DOI：
10.1152/japplphysiol.00628.2003
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发表时间：
2004-06-01
影响因子：
3.3
通讯作者：
Kowalski, KE
中科院分区：
文献类型：
--
作者：
DiMarco, AF;Connors, AF;Kowalski, KE
在患有膈肌麻痹的患者中，基底肺区的通气量减少，而在胸廓肌肉麻痹的患者中，上肺区的通气量减少。因此，仅由胸腔肌肉或膈肌收缩产生的吸气可能会导致通气和灌注不匹配以及气体交换障碍。为了验证这一假设，我们评估了 11 只麻醉狗在仅由膈肌或肋间肌收缩产生的通气过程中的气体交换。通过刺激膈神经实现膈肌激活。肋间肌激活是通过使用位于 T-2 脊髓水平硬膜外的电极进行电刺激来完成的。调整刺激参数以提供恒定的潮气量和吸气流速。在膈肌 (D) 和肋间肌呼吸 (IC) 期间，平均动脉 PO2 分别为 97.1 +/- 2.1 和 88.1 +/- 2.7 Torr (P < 0.01)。 D 期间的动脉 PCO2 低于 IC 期间（分别为 32.6 +/- 1.4 和 36.6 +/- 1.8 Torr；P < 0.05）。 IC 期间，耗氧量也高于 D 期间（分别为 0.13 +/- 0.01 和 0.09 +/- 0.01 l/min；P < 0.05）。 IC 和 D 期间肺泡-动脉氧差分别为 11.3 +/- 1.9 和 7.7 +/- 1.0 Torr (P < 0.01)。这些结果表明横膈膜呼吸比肋间肌呼吸明显更有效。然而，尽管吸气肌收缩模式存在显着差异，但通气分布与肺灌注保持良好匹配，从而保持正常的气体交换。
In patients with diaphragm paralysis, ventilation to the basal lung zones is reduced, whereas in patients with paralysis of the rib cage muscles, ventilation to the upper lung zones in reduced. Inspiration produced by either rib cage muscle or diaphragm contraction alone, therefore, may result in mismatching of ventilation and perfusion and in gas-exchange impairment. To test this hypothesis, we assessed gas exchange in 11 anesthetized dogs during ventilation produced by either diaphragm or intercostal muscle contraction alone. Diaphragm activation was achieved by phrenic nerve stimulation. Intercostal muscle activation was accomplished by electrical stimulation by using electrodes positioned epidurally at the T-2 spinal cord level. Stimulation parameters were adjusted to provide a constant tidal volume and inspiratory flow rate. During diaphragm ( D) and intercostal muscle breathing (IC), mean arterial PO2 was 97.1 +/- 2.1 and 88.1 +/- 2.7 Torr, respectively (P < 0.01). Arterial PCO2 was lower during D than during IC (32.6 +/- 1.4 and 36.6 +/- 1.8 Torr, respectively; P < 0.05). During IC, oxygen consumption was also higher than that during D (0.13 +/- 0.01 and 0.09 +/- 0.01 l/min, respectively; P < 0.05). The alveolar-arterial oxygen difference was 11.3 +/- 1.9 and 7.7 +/- 1.0 Torr (P < 0.01) during IC and D, respectively. These results indicate that diaphragm breathing is significantly more efficient than intercostal muscle breathing. However, despite marked differences in the pattern of inspiratory muscle contraction, the distribution of ventilation remains well matched to pulmonary perfusion resulting in preservation of normal gas exchange.