RESUMO
Under anesthesia and artificial respiration, all the dogs were injected with HCN 8 mg/kg intravenously. 2 minutes after HCN injection, 4-dimethylaminophenol( DM -AP) 3.2mg/kg,sodium nitrite(NaNO2)20 mg/kg,or dicobalt edetate(Co2EDTA) 15 mg/kg was given intravenously to different animals respectively. The changes of hemodynamics of the dogs were observed before and after the administration of the 3 HCN antidotes.It was found that intravenous injection of HCN rapidly induced a progressive decrease of heart rate(HR),stroke index(SI), cardiac index (CI),mean aortic pressure (MAP),left ventricular pressure(LVP) and ?dp/dtmax and a persistent increase of total peripheral vascular resistance (TPVR) and mean pulmonary arterial pressure (MPAP). If not treated,the dogs would died subsquently 4-9.5 minutes after HCN injection because of cardiac failure.2 to 8 minutes after DMAP administration, CI, MAP, LVP and?dp/dtmax increased markedly,and TPVR and MPAP would recover a little later. 4-6minutes after NaNO2 administration, ?dp/dtmax increased markedly, and CI, MAP, LVP, TPVR and MPAP returned to the normal. 6 minutes after Co2EDTA administration, MAP elevated markedly, LVP and?dp/dtmax returued to the normal, and C1, TPVR and MPAP would recover a little later. When observation was made again one hour after treatment, there was a remarkable decrease of blood pressure in NaNO2 and Co2EDTA treated animals and a slight decrease of blood pressure in DMAP treated ones.The conclusions based on the results are as follows:1. The ability of DMAP to restore the circulatory functions after HCN poisoning is more rapid and powerful than that of Co2EDTA or NaNO2.2. The cardiovascular functions restored by DMAP are more stable than those restored by the other two agents.3. DMAP and NaNO2 can rapidly reverse the HCN-iuduced damages on the cardiovascular functions, which may be a part of the anticyanide ability of these 2 drugs.
RESUMO
The effects of 4 efficacious cyanide antidotes, 4-dimethylaminophenol (4-DMAP) , P-aminopropiophenone hydrochloride (PAPP. HC1), NaNO2, and di-cobalt ethyleneamino-tetraacetate (Co2-EDTA), on the liver and kidney functions and on the blood gases and serum levels of lactate and potassium were investigated in rabbits. The former 3 agents can convert hemoglobin into me-themoglobin, and the dosages that are required to convert 30~35% of total hemoglobin into methemoglobjn are 15mg/kg, 35mg/kg, and 55 mg/kg for 4-DMAP, PAPP . HC1 and NaNO2 respectively. Obviously, 4-DMAP is the most potent one. Co2-EDTA can directly combine with cyanides to form nontoxic complex without affecting hemoglobin.According to the results of the 2-hour observation on the acute experiments in rabbits, all the 4 agents exert no harmful effects on the liver functions. 4-DMAP and PAPP. HC1 are also not harmful to the kidneys. But serum urea nitrogen was increased to 204% above the normal 30 minutes after intravenous NaNO2 (110 mg/kg) , and to 171% 90 minutes after intravenous Co2-EDTA(40 mg/kg) . Apparently, both the agents are injurious to the renal functions.4-DMAP can decrease the blood level of lactate. NaNO2 exerts most marked effect on the serum level of potassium. After the administration of 55 mg/kg and 110 mg/kg of NaNO2/the serum potassium level was increased 2.5 and 4.5 fold respectively. The larger the dose of NaNO2, the higher the serum potassium level, and more quickly the elevation of potassium level occurs.4-DMAP has a transient action on the arterial Po2 which usually returns to normal in 30 minutes. The action of NaNO2 and PAPP. HC1 on the blood gases are essentially similar, they can quickly lower the arterial Po2 but its recovery to normal is sluggish.