吸入沙丁胺醇对呼吸衰竭患者容积标限压力控制通气时通气参数的影响

目的　探讨在容积标限压力控制 (VTPC)通气时吸入支气管扩张剂沙丁胺醇后对机械通气参数的影响。方法　 10例平均年龄为 (6 8± 5 )岁的呼吸衰竭患者均接受气管插管与机械通气支持治疗 ;采用Newport e5 0 0型呼吸机 ,并实施定容型通气 (VCV) 30 min,潮气量 (VT)为 8～ 10 ml/ kg;测定气道阻力 (Raw)和静态顺应性 (Cst)以及通气参数的变化 ,包括气道峰压 (PIP)、平台压 (Pplat)、充气时间 (Tinflate)、吸气峰流速(PIF)、呼气峰流速 (PEF)和平均吸气流速 (VT/ Tinflate)。随后转为 VTPC通气 30 m in,并同样记录上述参数。通过同轴吸入装置吸入沙丁胺醇 6 0 0 μg后重复 VCV和 VTPC通气 ,并记录上述通气参数。结果　 10例患者的 Cst为 (38.4± 2 .7) ml/ cm H2 O,Raw为 (2 0 .1± 2 .0 ) cm H2 O· L- 1 · s- 1 。VTPC时 PIP和 VT/ Tinflate较 VCV时显著降低 (P均 <0 .0 5 ) ,PIF则显著增高 ,两种通气时的 Pplat无显著性差异 ,分别为 (2 2 .1± 0 .9) cm H2 O和(2 3.0± 1.2 ) cm H2 O(P>0 .0 5 )。吸入沙丁胺醇后患者的 Raw均显著降低 ,而 Cst无明显变化 ,VCV时的 PIP有所降低 ,但 Pplat无变化 ;VTPC时的 PIP和 Pplat与吸入前比较无明显改变 ,但 PIF和 PEF出现显著增高 ,Tinflate则相应缩短 (P均 <0 .0 5

Influence of salbutamol inhalation during volume target pressure control ventila tion on ventilation parameters in patients with respiratory failure

OBJECTIVE: To compare the effects of volume target pressure control ventilation (VTPC) and volume control ventilation (VCV) on respiratory mechanics in patients with respiratory failure, and to investigate the effects of ventilated parameters after salbutamol inhalation. METHODS: Ten patients with mean age (68+/-5) years were intubated and mechanically ventilated for acute respiratory failure of diverse causes. After 30 minutes with VCV [tidal volume (VT) 8-10 ml/kg], measurements of respiratory mechanics were begun, and then the patients were ventilated with VTPC for 30 minutes. VCV and VTPC were repeated after salbutamol 600 microg inhalation. RESULTS: The static compliance (Cst) was (38.4+/-2.7) ml/cm H2O (1 cm H2O=0.098 kPa) and airway resistance (Raw) was (20.1+/-2.0) cm H2O x L(-1) x s(-1) in 10 patients. With the same tidal volume, peak inspiratory pressure (PIP) and mean inspiratory flow [VT/inflation time (Tinflate)]during VTPC were lower, but peak inspiratory flow (PIF) was significantly higher than that during VCV (all P<0.05). The same plateau pressure (Pplat) was observed during VCV as during VTPC, they were (22.1+/-0.9) cm H2O vs. (23.0+/-1.2) cm H2O. After salbutamol inhalation, PIP and Raw were significantly decreased in all patients (both P<0.05), but no changes were found in Cst and Pplat. PIF and peak expiratory flow (PEF) were increased much more during two modes than before inhalation (both P<0.05), but Tinflate was decreased (P<0.05). CONCLUSION: VTPC is a new mechanical ventilation mode in which closed-loop control theory is used. The airway pressure during VTPC is associated with Cst and not influenced by Raw.