Figure 3.

Changes in arterial and mixed venous oxygen (upper graph; arterial oxygen tension is depicted by the square symbol and mixed venous oxygen tension by the circles) and carbon dioxide tensions (lower graph; arterial carbon dioxide tension is depicted by the diamond symbol and mixed venous carbon dioxide tension by circles) during sodium nitroprusside (SNP) infusion in all 8 pigs (duration of SNP infusion and times for placebo and sulfanegen injection are similar to Figure 1). The venous oxygen tension increased significantly as did the carbon dioxide tensions. There was also a significant decline in arterial oxygen tension (p < 0.05 at 2 hours vs control value at time 0). After SNP infusion, 4 pigs given saline placebo showed a marked decline in oxygen tensions associated with an increase in carbon dioxide levels just before death. The 4 pigs given sulfanegen sodium survived and showed recovery of arterial oxygen tension with normalization after two hours, as did the carbon dioxide levels (p > 0.05 at 5 hours vs control), pH, cyanide and lactate levels (C). The surviving pigs received 2 additional doses of sulfanegen sodium (2.5 g IV) at hours 3 and 4.