Figure 2. Effects of 8 h of sustained hypoxia on pulmonary artery systolic pressure with and without prior infusion of iron.

Upper panels show end-tidal partial pressures of oxygen () and carbon dioxide () during acute hypoxic challenges. Lower panels show corresponding measurements of pulmonary artery systolic pressure (PASP). Values are means and error bars indicate s.e.m. The control measurements demonstrate the normal pulmonary vascular response to sustained hypoxia, consisting of an increase in PASP and a sensitized PASP response to subsequent acute hypoxia (ΔPASP). Intravenous infusion of iron prior to the 8 h hypoxic exposure prevented the increase in baseline PASP (P < 0.001) and markedly attenuated the degree to which ΔPASP was sensitized (P = 0.002).