征象/症状尽管许多慢阻肺和急性加重患者有明确的氧疗适应证,但过度吸氧会进一步导致患者的呼吸生理恶化。吸氧引起供应通气不良区域的血管的缺氧性收缩减少,增加 V/Q 失衡的程度和/或肺内分流。[192]Robinson TD, Freiberg DB, Regnis JA, et al. The role of hypoventilation and ventilation-perfusion redistribution in oxygen-induced hypercapnia during acute exacerbations of chronic obstructive pulmonary disease. Am J Respir Crit Care Med. 2000;161:1524-1529.
http://www.ncbi.nlm.nih.gov/pubmed/10806149?tool=bestpractice.com
[193]Santos C, Ferrer M, Roca J, et al. Pulmonary gas exchange response to oxygen breathing in acute lung injury. Am J Respir Crit Care Med. 2000;161:26-31.
http://www.ncbi.nlm.nih.gov/pubmed/10619793?tool=bestpractice.com
过度氧疗还可能使红细胞携带 CO2 的能力下降(Haldane 效应)。[194]Hanson CW, 3rd, Marshall BE, Frasch HF, et al. Causes of hypercarbia with oxygen therapy in patients with chronic obstructive pulmonary disease. Crit Care Med. 1996;24:23-28.
http://www.ncbi.nlm.nih.gov/pubmed/8565533?tool=bestpractice.com
这些改变可以导致患者高碳酸血症和呼吸性酸中毒加重。部分呼吸驱动受损的患者也可以出现高碳酸血症加重。