Work of breathing in patients with chronic obstructive pulmonary disease in acute respiratory failure

In 11 spontaneously breathing patients with chronic obstructive pulmonary disease (COPD) in acute ventilatory failure, we measured the total inspiratory (WItot) and total resistive (WI + Eres) work rate of breathing, together with lung mechanics (dynamic pulmonary elastance and inspiratory and expiratory pulmonary flow resistance). All variables were markedly increased compared with those in normal subjects. No significant correlation was found between WItot and WI + Eres with lung mechanics data. However, when WItot and WI + Eres were expressed per liter of ventilation, a significant positive correlation was found with all lung mechanics data. These results indicate that although in patients acutely ill with COPD, work rate and work per liter of ventilation are increased, only the latter is related to the severity of pulmonary mechanical impairment, and it could be used as one of the criteria for extubation. In addition, our results indicate that at end-expiration the alveolar pressure was positive (range, 6 to 13 cm H2O) in all patients (intrinsic PEEP), a fact that must necessarily affect hemodynamics; furthermore, it imposes an extra burden on the inspiratory muscles.     

Mechanisms of hypertension in patients with chronic obstructive pulmonary disease and acute respiratory failure

PURPOSE: To investigate the effects of hypoxemia, hypercapnia, and cardiovascular hormones (norepinephrine, endothelin-1, and atrial natriuretic factor) on blood pressure during acute respiratory failure. PATIENTS AND METHODS: Patients with chronic obstructive pulmonary disease and acute respiratory failure were divided into four groups of 10 patients each: hypoxemia-normocapnia, hypoxemia-hypercapnia, hypoxemia-hypocapnia, and normoxemia-hypercapnia. Plasma norepinephrine levels were determined by high-performance liquid chromatography with electrochemical detection. Plasma endothelin-1 and atrial natriuretic factor levels were radioimmunoassayed after chromatographic preextraction.RESULTS: Systolic blood pressure and cardiovascular hormone levels were greater in patients with hypercapnia (whether or not they also had hypoxemia) than in those with normocapnia and hypoxemia. For example, in patients with hypercapnia and normoxemia, the mean (+/- SD) systolic blood pressure was 183+/-31 mm Hg and the mean norepinephrine level was 494+/-107 pg/mL, as compared with 150+/- 6 mm Hg and 243+/-58 pg/mL in those with normocapnia and hypoxemia (both P<0.05). Similar results were seen for endothelin-1 and atrial natriuretic factor levels, and for the comparisons of hypoxemic patients who were hypercapnic with those who were normocapnic. CONCLUSIONS: These results suggest that blood carbon dioxide levels, rather than oxygen levels, are responsible for hypertension during acute respiratory failure, perhaps as a result of enhanced sympatho-adrenergic activity.     

Respiratory drive in patients with chronic obstructive pulmonary disease

Respiratory drive (deltaP 0.1/deltaPCO2) and ventilatory response (deltaVE/deltaPCO2) to CO2 has been estimated in 20 normal subjects and 28 patients with chronic obstructive pulmonary disease (COPD). In patients with COPD, drive and ventilatory response to CO2 were diminished, but no statistical correlation with FEV1, MBC, TLC, FRC, RV/TLC was found. A statistically negative correlation was found between blood bicarbonate and drive or ventilatory response to CO2. Patients with emphysema and normal PaCO2 demonstrated normal deltaP 0.1/deltaPCO2. In contrast, patients with chronic bronchitis with the same pulmonary function abnormalities and hypercapnia had significant diminution of the deltaP 0.1/deltaPCO2. Therefore, we feel that pulmonary function abnormalities alone cannot explain the deltaP 0.1/deltaPCO2 decrease; in most cases there sould coexist a diminished respiratory sensitivity.     

双水平气道正压通气治疗慢性阻塞性肺疾病合并急性呼吸衰竭的临床研究

目的探讨经鼻面罩双水平气道正压（BiPAP）通气在慢性阻塞性肺疾病（COPD）合并急性呼吸衰竭早期的应用价值。方法将80例COPD合并急性呼衰患者分为2组，每组40例，在进行抗感染、对症等常规治疗的同时，分别给予持续静滴可拉明及经鼻面罩BiPAP通气治疗6小时，判断两组之间治疗前后生命体症及血气分析变化。结果两组治疗6小时后，机械通气组在血压、心率、呼吸频率方面改善均显著优于对照组（P〈0．01）；对照组pH值无改善，而机械通气组pH值显著改善，与对照组相比有显著差异（P〈0．01）；机械通气组和对照组治疗后均有PaO2上升和PaCO2下降，但机械通气组改善更明显，与对照组相比有显著差异（P〈0．01）。结论经鼻面罩BiPAP通气适合治疗COPD合并急性呼衰患者，其在改善临床症状和动脉血气指标方面均优于常规治疗，值得临床推广。     

双水平气道正压通气治疗慢性阻塞性肺疾病合并急性呼吸衰竭的临床研究

目的探讨经鼻面罩双水平气道正压(BiPAP)通气在慢性阻塞性肺疾病(COPD)合并急性呼吸衰竭早期的应用价值。方法将80例COPD合并急性呼衰患者分为2组,每组40例,在进行抗感染、对症等常规治疗的同时,分别给予持续静滴可拉明及经鼻面罩BiPAP通气治疗6小时,判断两组之间治疗前后生命体症及血气分析变化。结果两组治疗6小时后,机械通气组在血压、心率、呼吸频率方面改善均显著优于对照组(P<0.01);对照组pH值无改善,而机械通气组pH值显著改善,与对照组相比有显著差异(P<0.01);机械通气组和对照组治疗后均有PaO2上升和PaCO2下降,但机械通气组改善更明显,与对照组相比有显著差异(P<0.01)。结论经鼻面罩BiPAP通气适合治疗COPD合并急性呼衰患者,其在改善临床症状和动脉血气指标方面均优于常规治疗,值得临床推广。     

慢性阻塞性肺疾病并发呼吸衰竭的治疗

慢性阻塞性肺疾病(COPD)是呼吸系统的常见病和多发病,呼吸衰竭是COPD致死的主要原因,积极治疗呼吸衰竭具有重大意义.本文对氧疗、呼吸兴奋剂、机械通气在COPD急性加重期和稳定期呼吸衰竭的治疗作用及相关进展进行综述.     

慢性阻塞性肺病并发急性呼吸衰竭的危险因素分析

目的探讨慢性阻塞性肺疾病(COPD)并发急性呼吸衰竭的相关危险因素及预后因素,为临床防治策略的制定提供参考依据。方法选取我院呼吸内科收治的COPD患者148例,根据是否有并发急性呼吸衰竭分为急性呼衰组52例和非急性呼衰组96例。根据急性呼衰组患者的转归情况,将其分为好转组36例以及死亡组16例。分析慢性阻塞性肺疾病并发急性呼吸衰竭的危险因素,并研究急性呼吸衰竭预后的相关因素。结果每年发生慢性阻塞性肺病急性发作次数多、尿酸水平低、白蛋白水平低、消瘦、发生医院感染、未使用吸入用糖皮质激素、酸碱失衡是COPD致急性呼吸衰竭的危险因素;而酸碱值低、血二氧化碳分压升高、血清钠降低、血清氯低、医院感染、并发肺性脑病、并发心功能衰竭是COPD并发急性呼吸衰竭患者预后的危险因素。结论慢性阻塞性肺疾病并发急性呼吸衰竭与COPD发作的次数、机体营养状况、电解质酸碱失衡、医院感染的发生、吸入用糖皮质激素的使用等多个危险因素有关。     

鼻肠管在慢性阻塞型肺病呼吸衰竭患者中的应用

目的经鼻肠管实施肠内营养支持,维持慢性阻塞型肺病呼吸衰竭患者的营养需要。方法比较鼻胃管和鼻肠管二者在治疗慢性阻塞型肺病呼吸衰竭患者营养支持疗效观测。结果鼻肠管在治疗慢性阻塞性肺病呼吸衰竭患者在住院时间,并发症等方面均少于鼻胃管。结论鼻肠管是临床上进行营养支持的有效手段,在慢性阻塞性肺病呼吸衰竭患者身上使用就更为有效。     

Effects of digoxin on diaphragmatic strength generation in patients with chronic obstructive pulmonary disease during acute respiratory failure

We studied the effects of digoxin, a compound that has an inotropic effect on the myocardium, on diaphragmatic function in 8 patients with chronic obstructive pulmonary disease. All the patients were in acute respiratory failure and were artificially ventilated. Diaphragmatic strength was assessed by measuring the transdiaphragmatic pressure generated at functional residual capacity during bilateral supramaximal electrical stimulation of the phrenic nerves. The latter were stimulated before and at 45 and 90 min after administration of digoxin (0.02 mg/kg infused for 10 min). In all the patients, cardiac output was measured by the thermodilution technique using a Swan-Ganz catheter placed in the pulmonary artery. Arterial blood gases and pH were maintained within normal range by mechanical ventilation. In all the patients, digoxin plasma levels reached the therapeutic range (mean values, 2.82 +/- 0.17 and 2.90 +/- 0.20 nmol/L at 45 and 90 min, respectively) after digoxin administration. Diaphragmatic strength improves significantly after digoxin administration, the transdiaphragmatic pressure for an identical phrenic stimulation increasing by 19.5% (p less than 0.001) on the average. This increase was noted 45 and 90 min after digoxin administration. We conclude that digoxin has a potent effect on diaphragmatic strength generation that may be beneficial in patients with chronic obstructive pulmonary disease during acute respiratory failure. Furthermore, this inotropic positive effect of digoxin on the diaphragm, as previously observed for the myocardium, emphasizes the similarities between these 2 contractile tissues.     

Neural respiratory drive and neuromuscular coupling in patients with chronic obstructive pulmonary disease (COPD)

In 15 spontaneously breathing patients with chronic obstructive pulmonary disease (COPD) divided into two groups, one with normocapnia (A) and one with chronic hypercapnia (B), we evaluated the maximal voluntary inspiratory muscle strength (MIP), the pattern of breathing, the mouth occlusion pressure (Po.1), the neural respiratory drive (NRD), assessed by surface electromyographic (EMG) activity of the diaphragm (EMGd) and EMG activity of intercostal muscles (EMGint), and the chest wall neuromuscular coupling, assessed in terms of Po.1/EMGd ratio. Compared with an age-matched normal control group, both A and B groups exhibited lower MIP, significantly greater EMGd and EMGint, and lower Po.1/EMGd ratio. However, a similar pattern, along with a rapid and shallow breathing, differentiated group B from group A. In group B we found a significant direct relationship between Po.1/EMGd ratio and MIP, and an inverse relationship between PaCO2 and Po.1/EMGd ratio. These data seem to indicate the following: (1) EMG is a more precise method than Po.1 in assessing the magnitude of the NRD; (2) NRD is increased in these patients; and (3) clinical manifestations probably associated with inspiratory muscle fatigue (marked decrease in muscle strength, rapid and shallow breathing, and alveolar hypoventilation) may be accompanied by a greater NRD and a more marked derangement in chest wall neuromuscular coupling in COPD.     

纤维支气管镜救治慢性阻塞性肺疾病合并呼吸衰竭30例分析

目的 探讨纤维支气管镜治疗慢性阻塞性肺疾病(chronic obstructive pulmonary disease,COPD)合并呼吸衰竭的临床疗效.方法 将60例COPD合并呼吸衰竭的患者随机分为治疗组和对照组,每组30例;对照组常规抗感染、祛痰、吸氧等对症治疗,治疗组在此基础上通过纤维支气管镜吸痰、支气管肺泡灌...     

盐酸氨溴索（沐舒坦）在AECOPD合并呼吸衰竭者的临床观察

目的探讨沐舒坦在慢性阻塞性肺疾病急性期（AECOPD）合并呼吸衰竭者的临床疗效及安全性。方法将120例AECOPD合并呼吸衰竭者按系统抽样和分层抽样相结合分成三组,对照组40人,治疗组（1）40人,治疗组（2）40人。三组均使用抗生素,吸氧,支气管扩张剂等常规治疗,同时治疗组（1）给予雾化吸入沐舒坦30 mg,每日两次,每次20 m in;治疗组（2）给予静滴沐舒坦150 mg,每日1次。观察三组患者的症状及血气改善情况并分析。结果治疗组在临床疗效、祛痰作用和综合临床评价等方面其治疗后都较治疗前有显著改善（P〈0.05）。结论沐舒坦在AECOPD合并呼衰者使用疗效确切,使用安全,能够作为临床常规运用。     

慢性阻塞性肺疾病患者晚期反复发生严重呼吸衰竭的机械通气治疗

总结对慢性阻塞性肺疾病合并严重呼吸衰竭患者反复多次气管插管进行机械通气的经验。方法回顾性分析因ＣＯＰＤ急性加重而机械通气３次以上的１５例患者的临床资料及随访结果。结论对晚期ＣＯＰＤ合并严重呼吸衰竭患者实施反复多次的机械通气可延长生存期。     

Flow resistance in patients with chronic obstructive pulmonary disease in acute respiratory failure. Effects of flow and volume

The flow and volume dependence of the total resistance of the respiratory system (Rrs) was investigated in six mechanically ventilated patients with chronic obstructive pulmonary disease (COPD) using a simple, rapid method. Isovolume Rrs-flow (V) relationships obtained at different inflation volumes (range 0.1 to 1 L) fitted (p less than 0.001) the following function: Rrs = a/V + b + cV, where a, b, and c are constants. The term "a/V" in this equation represents the hyperbolic decrease in thoracic tissue resistance with increasing flow; the term "cV" represents the linear increase in airway resistance with increasing flow. Rrs initially decreased with increasing V because at low flow the weight of the a/V was greater than that of the cV. At higher flow, however, cV became predominant and hence Rrs tended to increase. At an inflation volume of 0.5 L, minimum Rrs occurred at average inflation flow of 1.28 L/s. At low flow, Rrs increased progressively with increasing inflation volume; at inflation V greater than 1 L/s, the highest values of Rrs were obtained at low inflation volumes. The flow and volume dependence of Rrs implies that, for comparative purposes, measurements of Rrs should be standardized to a fixed inflation flow and volume.