Cerebral blood flow, circulation, and blood homeostasis of dogs during slow cyanide poisoning and after treatment with 4-dimethylaminophenol.

The effects of 4-dimethylaminophenol . HCl (DMAP) and 100% oxygen on cerebral blood flow (CBF) and peripheral circulation, arterial and venous blood gases, and other parameters have been investigated in dogs in the course of slow cyanide infusion. The i.v. infusion of KCN increased the respiratory minute volume, accompanied by a rise in arterial pO2 and pH and a decrease in arterial pCO2 while the venous lactate concentration increased by about 500% and the hemoglobin content and hematocrit by about 30%. Heart rate and carotid artery blood flow decreased. Local CBF in the cingulum as measured with thermocouples rose steadily, and the brain and oesophagus temperature were lowered. The breathing of 100% oxygen raised the local CBF, the temperature, and the arterial pCO2. During the infusion of KCN into the femoral artery of artificially ventilated dogs the femoral venous pO2 increased continuously by some 40 mm Hg, attended with a decrease in pCO2 of 15 mm Hg. The femoral blood flow, however, rose sharply within 3 min. 100% oxygen induced a rise in pCO2 and a diminution of pH in the femoral vein and in the sinus sagittalis, and the femoral flow rose rapidly. After DMAP i.v. the values of most of the parameters returned to normal or finally stabilized below or above the initial level. The rise in the hemoglobin content, hematocrit, and lactate concentration was stopped, but the arterial and venous pH remained or were lowered. DMAP elicited a rapid, strong decrease in the pO2 of the femoral vein and the sinus sagittalis with a concomitant marked increase in pCO2.