which指代什么？This 又指代什么？

Clearance of gas loculi in the body may be greatly accelerated by the inhalation of oxygen, which greatly reduces the total partial pressure of the dissolved gases in the venous blood (Table 25.2). This results in the capillary blood having additional capacity to carry away gas dissolved from the loculi. Total gas partial pressures in venous blood are always slightly less than atmospheric, and this is critically important in preventing the accumulation of air in potential spaces such as the pleural cavity, where the pressure is subatmospheric. Oxygen is therefore useful in the treatment of air embolism (page 346) and pneumothorax (page 361)

氧疗可以大大加速体内气腔气体的清除，从而显著降低静脉血中溶解气体的压力（表25.2）。这导致毛细血管血液具有额外的能力来带走小腔中溶解的气体。（不吸氧时）静脉血中的气体压力总是略低于大气压，这对于防止空气在潜在空间（如负压的胸腔）积聚至关重要。因此，氧气可用于治疗空气栓塞（第346页）和气胸（第361页）。

Clearance of gas loculi in the body may be greatly accelerated by the inhalation of oxygen, which greatly reduces the total partial pressure of the dissolved gases in the venous blood (Table 25.2).

which指前面整个一句话，还是就指“ the inhalation of oxygen”

1.which指前面整个一句话，就是：氧疗可以大大加速体内气腔气体的清除，从而显著降低静脉血中溶解气体的压力

2.which就指“ the inhalation of oxygen”，就是：氧疗可显著降低静脉血中溶解气体的压力，从而大大加速体内气腔气体的清除

This 又指代什么？