Figure 1From: Physiology in medicine: importance of hypoxic pulmonary vasoconstriction in maintaining arterial oxygenation during acute respiratory failureEffects of HPV in COPD, a lung disease characterized by VA/Q mismatching, and in ARDS, a disease characterized by an increased shunt. LogSD VA/Q, logarithmic standard deviation of lognormal VA/Q distribution. FIO2 was set at 0.3 in COPD and 0.4 in ARDS. (Reproduced with permission from [16].)Back to article page