DEADSPACE AND THE SINGLE BREATH TEST FOR CARBON-DIOXIDE DURING ANESTHESIA AND ARTIFICIAL-VENTILATION
DEADSPACE AND THE SINGLE BREATH TEST FOR CARBON-DIOXIDE DURING ANESTHESIA AND ARTIFICIAL-VENTILATION
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DOI：
10.1093/bja/56.2.109
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发表时间：
1984-01-01
影响因子：
9.8
通讯作者：
JONSON, B
中科院分区：
文献类型：
--
作者：
FLETCHER, R;JONSON, B
采用单次呼气CO2试验（SBT-CO2）对58例芬太尼或哌替啶间歇正压通气麻醉患者的生理死空（VDphys）组成进行了研究。采用方波吸气流和吸气末暂停（分别为循环时间的25%和10%）。在潮气量[VT]为0.45 l （f[呼吸频率]= 17 b.p.m.[呼吸/分钟]）和0.75 l （f = 9 b.p.m.）时，VDphys/VT的中位数分别为0.44和0.31。增加VT和降低f并没有改变气道死亡空间（VDaw），而是使VDaw/VT分数降低（P < 0.001）。93%的患者肺泡死亡空间分数（VDalv/VTalv）降低（P < 0.001）。随着VT的增加，这些改善可以归因于气体分布和扩散时间的有利影响。肺泡死腔大的患者SBT-CO2期明显倾斜，呼吸系统呼气时间常数增高。中位动脉-潮末PCO2 [CO2分压]差（PaCO2-PECO2）在小VT时为0.6 kPa[千帕斯卡]，在大VT时为0.3 kPa （P < 0.001）。3例患者在大VT时PaCO2-PECO2值为零，4例为负。当III期斜坡陡峭时，在VDalv存在时可能观察到PaCO2-PECO2值为负。
Using the single breath test for CO2 (SBT-CO2), the components of physiological deadspace [VDphys] were investigated during [fentanyl or pethidine] anesthesia with IPPV [intermittent positive pressure ventilation] in 58 patients. A square-wave inspiratory flow and an end-inspiratory pause (25 and 10% of cycle time, respectively) were used. At tidal volumes [VT] of 0.45 l (f [respiratory frequency] = 17 b.p.m. [breaths/min]) and 0.75 l (f = 9 b.p.m.), median values for VDphys/VT were 0.44 and 0.31. Increasing VT and decreasing f did not change airway deadspace (VDaw) so that the fraction VDaw/VT was decreased (P < 0.001). The alveolar deadspace fraction (VDalv/VTalv) was decreased in 93% of patients (P < 0.001). These improvements with increasing VT can be attributed to beneficial effects on gas distribution and diffusion time. Patients with large alveolar deadspaces had steeply sloping SBT-CO2 phase III and increased expiratory time constants of the respiratory system. The median arterial-end-tidal PCO2 [CO2 partial pressure] difference, (PaCO2-PECO2), was 0.6 kPa [kiloPascal] at small and 0.3 kPa at large VT (P < 0.001). Three patients had zero and 4 had negative (PaCO2-PECO2) values at large VT. When phase III slopes steeply, negative (PaCO2-PECO2) values may be observed in the presence of VDalv.