Studies on the effect of hydrogen peroxide on methemoglobin formation
Since Oliver and Murphy(1920) first administered hydrogen peroxide intravenously for the treatment of influenzal pneumonia, attempts have been made to use it parenterally as a source of oxygen, both in humans and in animals. Lorincz et al. (1948) investigated the effect of hydrogen peroxide on the blood of several animals and concluded it was of little therapeutic value because of the formation of oxygen emboli. Feldman et al. (1966) reported that cats have been kept alive for periods up to one hour in the abscence of pulmonary ventilation by an infusion of hydrogen peroxide into the thoracicaorts. Stern and Brennock(1967) investigated the effect of the continuous hydrogen peroxide infusion, and reported that there were massive emboli in dogs but not in cats. Fuson et al.(1967) observed that intravenous hydrogen peroxide could supply up to 20% of oxygen consumption in pigs, but they observed severe methemoglobinemia and suggested that it was a harzadous technique. Yun(1969) investigated the effect of hydrogen peroxide enemas on dogs and rabbits and reported the elevation of arterial oxygen tension without gas emboli. Paik(1970) undertook a histological study on rabbit liver following hydrogen peroide enema, and reported no pathological changes below 0.75 percent. He recommended that hydrogen peroxide could be used safely, below 0.75% by enema.
Kim(1971) investigated the effect of 0.5% hydrogen peroxide enema in hyposic cats, and observed significant elevationof arterial oxygen tension.
The present investigation is aimed at studying the effect of methemoglobin formation by intravenous injection and enemas of hydrogen peroxide. Also, the author has studied the effect of intravenous hydrogen peroxide injection on arterial pH, Po^^2 and Pco^^2.
In this experiment 70 adult cats, 95 adult rabbits and 45 adult dogs, of either sex, were used. The intravenous injection group was separated from the enema group according to the method of infusion and all experimental animals were anesthetized with intravenous injections of seconal (30mg/kg).
In the intravenous hydrogen peroxide injection group, a tracheotomy was performed and a cannula was inserted in cats and rabbits, while doges were endotracheally intubated. A respirator (Model 607, Harvard Apparatus Co.) was connected to the experimental animals for regulation of their respiratory rate and volume. Respiration was performed with room air and hypoxic gas of 10% oxygen in 90% nitrogen. Under the state of arterial desaturation by means of hypoxic gas, 0.5% and 0.75% hydrogen peroxide (10ml/kg) were injected in the experimental group and
saline (10ml/kg) was injected to the control group. The injection was made intravenously for 75 minutes through femoral vein. Blood samples were collected, through the femoral artery, during air breathing, hypoxic breathing, and then 15, 45 and 75 minutes after the intravenous injection was started in order to evaluate
arterial pH, Po^^2 and Pco^^2. Blood samples were also collected before the intravenous injection and 40,90 and 180 minutes after intravenous injection in order to evaluate methemoglobin.
The enema group was divided into the hydrogen peroxide group, the hydrogen peroxide plus human whole blood group and the control group. In the hydrogen peroxide enema group a long rectal tube was inserted and sutured at the anas to prevent leakage from the infusion with hydrogen peroxide. In cats, an enema was performed with 0.5% hydrogen peroxide (10ml/kg) and human whole blood(1ml/kg) in the experimental group and with saline (10ml/kg) in the control group. In rabbits, an enema was performed with hydrogen peroxide (10ml/kg) of 0.5%, 0.75% and 1% in the hydrogen peroxide group, with hydrogen peroxide (10ml/kg) of 0.5%, 0.75%, 1%, 1.5%, 2% and 3% with human whole blood (1ml/kg) in the hydrogen peroxide plus human whole blood group and with saline (10ml/kg) in the control group. In dogs, an enema was performed with 0.5% hydrogen peroxide (10ml/kg) in the hydrogen peroxide group, with 0.5% hydrogen peroxide (10ml/Kg) and hman whole blood (1ml/kg) in the hydrogen peroxide plus human whole blood group, and with saline (10ml/kg) in the control group. The blood samples were collected, through the femoral arter, before enema and 40 and 90 minutes after enema in order to evaluate methemoglobin.
pH, Po^^2 and Pco^^2 were measured with Astrup's Radiometer (1960), methemoglobin was measured by the method of Evely and Malloy (1938), and autopsies were performed on expired animals for the evaluation of oxygen emboli.
The following results were obtained:
1. There were no significant changes in arterial pH and Pco^^2 before and after intravenous hydrogen peroxide injection.
2. There were no significant elevation of arterial Po^62 in cats and rabbits during intravenous hydrogen peroxide injection but significant diminution of arterial Po^^2 was observed in dogs during intravenous hydrogen peroxide injection.
3. Two of ten cats, two of ten rabbits and all dogs expired during intravenous injection of 0.75% hydrogen peroxide, and autopsies showed massive oxygen emboli in the inferior vena cava and pulmonary artery.
4. There was marked elevation of methemoglobin in dogs, and slight elevation in cats and rabbits after intravenous hydrogen peroxide injection. There were no changes in methemoglobin in cats and rabbits after hydrogen peroxide enema, and a slight elevation of methemoglobin in dogs after hydrogen peroxide enema only, with no changes in methemoglobin in dogs after an enema of hydrogen peroxide with human whole blood.
The results obtained from these experiments indicate that it is impossible to use the method of intravenous hydrogen peroxide injection due to it not only being effective in raising arterial Po^^2 but is dangerous due to the formation of oxygen emboli. However, the method of enema with hydrogen peroxide, especially with human whole blood, can be used safely because of little effect in methemoglobin formation.