ELECTROCARDIOGRAM DURING SPINAL ANESTHESIA—ON CHANGES OF ELECTROCARDIOGRAM IN SO-CALLED SPINAL ANESTHETIC SHOCK

Abstract

1. The electrocardiogram during spinal anesthesia was taken in 79 urologically operated cases and its changes of spinal anesthetic shocked patients were observed.
2. Low spinal anesthesia by that cardiac accelerater nerves are not paralyzed was used, and in order to keep the hypotensive anesthetic effect, blood transfusion, fluid transfusion and cardiotonic drugs were limited in this study. Electrocardiogram was observed by osilloscope at all times and recorded if necessary.
3. Electrocardiogram does not change so much except gradually prolonged R-R duration. This prolonged R-R duration appears with the gradual decrease of the blood pressure and it is thought as a result from vagotonia occured by sympathetic paralysis during spinal anesthesia.
4. Secondarily, the changes of electrocardiogram in the so-called spinal anesthetic shock occured about three minutes following the spinal anesthesia were investigated. R-R duration prolonged rapidly with the rapid decrease of blood pressure and the patient often complained of vomiting and sleepness simultaneously in the cases so called spinal anesthetic shock. It is resumed that this shock may be the first type of shock due to vagal reflex as Shibuzawa called. This type of shock usually recovers after about 15 minutes, but it may not be asserted that this vagal reflex would not change to serious and irreversible shock.
5. Nine percent of spinal anesthetic shocked patients was found by uncontinuous measurement of blood pressure during operation, but on the electrocardiogram, it was found fifty percent of rapid and temporary prolongation of R-R duration in it. I call this condition as an invisible spinal anesthetic shock. Prolongation of P-Q interval, A-V block, nodal rhythm, superventricular premature beat, A-V dissociation and S-A block were also obseeved,
6. The temporary increase of P wave amplitude was observed in about half cases immediately after the spinal anesthesia, it continued about 10 to 20 minutes and may be thought as a pulmonary P caused by the temporary insufficiency of respiration.
7. T wave increased in amplitude gradually after the spinal anesthesia. T wave immediately after the termination of the operation is higher than T wave before operation. It is thought that elevated serum potassium by operation takes an important role for the gradually inceased T wave amplitude.
8. Depression of ST segment was observed frequently in the old patients and the patients with the abnormal electrocardiogram before operation. It is not a specific sign of the so-called spinal anesthetic shock.
9. Rapid elevation of blood pressure and marked prolongation of R-R duration was seen in some cases following the injection of noradrenaline, and nodal rhythm and superventricular premature beat were also observed.