Regulação autonomica central na parada cardiorrespiratoria : estudo experimental

AUTOR(ES)
DATA DE PUBLICAÇÃO

1997

RESUMO

There is nowadays a relatively high incidence of spinal cord trauma. During the acute phase , cardiac arrest (CA) is often a possibility due to serious autonomic disorders and hypoxemia, which is the result of respiratory problems. Alpha adrenergic drugs, by increasing the peripheral arterial tone, are responsible for elevating the coronary perfusion pressure (CorPP) and for restoration of spontaneous circulation (ROSC) during cardiopulmonary resuscitation (CPR) maneuvers. This study evaluated the cardiocirculatory effects of noradrenaline (NOR - adrenergic vasopressor) and angiotensin 11 (AlI - non adrenergic vasopressor) on intact anesthetized dogs, and after the acute disconnection of the sympathetic nervous system . Investigations were also conducted to observe the effects of high doses of these drugs on CorPP and ROSC during CPR of electrical1y induced ventricular fibril1ation. Twenty, male and female anesthetized mongrel dogs had orotracheal intubation and mechanical ventilation. The aortic pressure (Ao P), the right atrial pressure (RAP) and the electrocardiogram (EKG) were registered continuously. The animais were divided equal1y into two groups (group A - NOR and B - AlI) . The data were analyzed in three phases. The hemodynamic alterations resulting from the drugs were reported in animaIs having no Jesions, in phase I; in animais having lesions, in phase 11 and in animaIs having CPR, in phase In. The standard hemodynamic response observed in group A was an increase in the systemic arterial pressure during phase I and 11 with intense initial effects, especial1y seen on the diastolic Ao P and Cor PP of injured animais rather than those of intact ones . These effect were ephemeral and disappeared two minutes after administering the drugs . NOR- bradycardiac effects were not seen in the injured animaIs, contrary to the observed in the intact ones. The standard hemodynamic response observed in group B was an increase in the arterial systemic pressure during phase I and 11, having intense initial pressor effects on the diastolic AoP and Cor PP in injured animaIs than in intact ones. The effects in this group were more intense and lasted longer thépl in group A, in both phases. The heart rate did not change significant1y in injured anirnals during phase 11. In phase 111 (CPR), NOR and AlI in high doses were both significt1y effective for increasing CorPP and restoring spontaneous circulation in injured animais. It can be conc1uded that NOR and AlI arterial pressor effects were more intense in injured rather than in intact animaIs. The bradycardiac effects of NOR were totally annuled after serious medullary lesion. In injured animaIs especially, the pressor effects of AlI were apparently more intense and longer lasting than that of NOR. After injury, the complete disconnection of the sympathetic nervous system did not preclude the initial vascular response when high doses of NOR and AlI were administered during CPR. A significant increase in Cor PP and high rates of ROSC were observed during the CPR of ventricular fibrillation

ASSUNTO(S)

sistema nervoso autonomo noradrenalina ressuscitação cardiopulmonar traumatismo

ACESSO AO ARTIGO

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