Cerebral resuscitation after cardiac arrest using hetastarch hemodilution, hyperbaric oxygenation and magnesium ion

This study was done to investigate the effects of hemodilution, hyperbaric oxygenation, and magnesium sulfate on cerebral resuscitation. Sixteen mongrel dogs were anesthetized, and monitored via pulmonary artery catheter, arterial catheter and electrocardiogram. A left lateral thoracotomy was done. Ventricular fibrillation was obtained by application of a 6-volt AC current. Mechanical ventilation was stopped. Total arrest time was 12 min. All dogs were cardiac resuscitated within 6 min using internal massage, ventilation, bicarbonate, epinephrine and internal defibrillation. The animals were then randomized into three groups. Group I represented controls, and were not treated. Group II dogs received normvolemic hemodilution using hetastarch (Hespan) containing magnesium sulfate (2000 mg/l), resulting in a hematocrit of 20%-30%. Group III dogs received the above hemodilution plus compression in a hyperbaric oxygen chamber to 2 atmospheres absolute. Critical care management and hourly neurologic scoring was performed for 7 days by blinded observers. All dogs at the time of death underwent autopsies for gross study. Data analysis revealed no statistical difference among the three groups with respect to survival time, cardiac function or neurologic scoring.