Scano G, Seghieri G, Mancini M, Filippelli M, Duranti R, Fabbri A, Innocenti F, Iandelli I, Misuri G
Fondazione Don C. Gnocchi, Pozzolatico ONLUS, Florence, Italy.
Clin Sci (Lond). 1999 May;96(5):499-506.
Dyspnoea and pulmonary dysfunction have recently been associated with Type I (insulin-dependent) diabetes mellitus. The putative role of altered pulmonary mechanics and of performance of inspiratory muscles in inducing dyspnoea has not been yet assessed in Type I diabetes. To better focus on this topic we evaluated nine patients with Type I diabetes mellitus, aged 19 to 48 years with good and stable metabolic control, without a history of smoking and microvascular complications, alongside a group of 14 healthy control subjects. In each subject, pulmonary volumes, static and dynamic compliance, pleural pressure swings (Pplsw), maximal inspiratory pressures (Pplsn), Pplsw(%Pplsn), a measure of respiratory muscle effort, and tension-time index [TTI=TI/TTOTxPplsw(%Pplsn)] were measured (TI=inspiratory time;TTOT=total time of the respiratory cycle). All subjects were studied at baseline and during hypoxic rebreathing. Patients had normal pulmonary volumes. During hypoxic rebreathing, a normal change in respiratory muscle effort [DeltaPplsw(%Pplsn)/DeltaSaO2] and DeltaTTI/DeltaSaO2, and a lower change in tidal volume versus change in oxygen saturation [DeltaVT(% vital capacity)/DeltaSaO2], resulted in a higher ratio of respiratory effort to tidal volume [Pplsw(%Pplsn)/VT(% vital capacity)], a measure of neuroventilatory dissociation of the respiratory pump. Hypoxic dyspnoea, assessed by a modified Borg scale, showed a greater rate of rise (DeltaBorg/DeltaSaO2) and a greater increase for a given level of respiratory effort in patients. Moreover, neuroventilatory dissociation related to the expression of peripheral airway involvement, as assessed in terms of low dynamic compliance, and to concurrent change in dyspnoea sensation. Patients with Type I diabetes mellitus under good metabolic control and with normal lung volumes may have abnormal peripheral airway function. The latter is thought to be responsible for the association between dyspnoea sensation and neuroventilatory dissociation.
呼吸困难和肺功能障碍近来被认为与Ⅰ型（胰岛素依赖型）糖尿病有关。在Ⅰ型糖尿病中，肺力学改变和吸气肌功能在引发呼吸困难中的假定作用尚未得到评估。为了更深入地研究这一课题，我们评估了9例年龄在19至48岁之间、代谢控制良好且稳定、无吸烟史和微血管并发症的Ⅰ型糖尿病患者，并与14名健康对照者进行了比较。对每位受试者测量了肺容量、静态和动态顺应性、胸膜压力波动（Pplsw）、最大吸气压力（Pplsn）、Pplsw(%Pplsn)（一种呼吸肌用力的测量指标）以及张力-时间指数[TTI=TI/TTOTxPplsw(%Pplsn)]（TI=吸气时间；TTOT=呼吸周期总时间）。所有受试者均在基线状态及低氧再呼吸期间接受研究。患者的肺容量正常。在低氧再呼吸期间，呼吸肌用力的正常变化[DeltaPplsw(%Pplsn)/DeltaSaO2]和DeltaTTI/DeltaSaO2，以及潮气量变化与氧饱和度变化的比值降低[DeltaVT(%肺活量)/DeltaSaO2]，导致呼吸用力与潮气量的比值升高[Pplsw(%Pplsn)/VT(%肺活量)]，这是呼吸泵神经通气解离的一种测量指标。通过改良的Borg量表评估的低氧性呼吸困难在患者中显示出更高的上升速率（DeltaBorg/DeltaSaO2）以及在给定呼吸用力水平下更大的增加幅度。此外，神经通气解离与外周气道受累的表现相关，以外周气道低动态顺应性来评估，并且与呼吸困难感觉的同时变化相关。代谢控制良好且肺容量正常的Ⅰ型糖尿病患者可能存在外周气道功能异常。后者被认为是呼吸困难感觉与神经通气解离之间关联的原因。
