Figure 2.

Responses during and after ethyl nitrite (ENO) dosing in hypoxic sheep. Time courses are presented as mean ± standard deviation of (a) percent arterial blood oxygen saturation, SaO₂%; (b) percent methemoglobin, Met-Hb%; (c) mean arterial pressure, MAP, in mm Hg; (d) heart rate, HR, in beats per min; (e) cardiac output, CO, in liters per min; (f) mean pulmonary arterial pressure, mPAP, in mm Hg; (g) percent systemic venous oxygen saturation, SvO₂%; and (h) systemic vascular resistance, SVR, in dynes*sec*cm⁻⁵. The standard deviations (error bars) are marked every 30 min for clarity. Hypoxia was initiated for 1 h starting at time 0 (normoxic baseline) then sheep received either 0 (n = 8; blue line), 1 (n = 8; red line), or 50 (n = 7; black line) ppm ENO for 4 h followed by an additional 4 h under hypoxia alone. ENO produced significant dose-dependent increases in CO and declines in SvO₂ and SVR that carried into the postexposure period. See text for additional details.