Resuscitation
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Comparative Study
Cerebral blood flow during conventional, new and open-chest cardio-pulmonary resuscitation in dogs.
The following parameters were monitored simultaneously in 15 dogs, in order to evaluate the efficacy of conventional CPR (C-CPR), new CPR (N-CPR), and open-chest CPR (O-CPR) on cerebral perfusion: arterial blood pressure (BP), central venous pressure (CVP), intrathoracic airway pressure, blood flow in carotid artery, intracranial pressure (ICP), sagittal sinus blood flow (sinus BF) and pressure (sinus P), and blood flow in cerebral cortex (cortical BF). The sinus blood flow was measured by the direct-method and with a cannulating electromagnetic flowmeter. The cortical blood flow was measured with a termocouple tissue flowmeter. ⋯ Sinus blood flows/min were 18, 18 and 42%, and sinus blood flows per stroke were 55, 45 and 127% of control values, respectively; the differences between C-CPR and N-CPR were not significant. This was also true for cortical blood flow. From this we conclude that, firstly, N-CPR is not significantly better than C-CPR in cerebral perfusion because of its accompanying high intracranial pressure, secondly, O-CPR is far superior to the other two methods in respect of cerebral perfusion.
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This study was conducted to investigate the degree of insult from asphyxia leading to total body circulatory arrest, as a model for brain resuscitation studies in rats. Of 78 male rats, 68 were anesthetized with halothane in O2/N2O, controlled ventilated, paralyzed with pancuronium and asphyxiated, 5, 7.5, 10, 12.5 and 15 min, respectively. Asphyxiation led to circulatory arrest in 244 +/- 22 s (mean +/- S. ⋯ This study indicates the feasibility of an asphyxial insult in rats for use in resuscitation studies of short duration. Although 24 h post-insult recovery is possible, up to 6 h seems most practical, with asphyxia of 7.5-10 min most successful and controllable. Questions are raised about the effects of irritation during the post-insult intensive care on both neurological deficit and neuropathology scores.
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This study in 53 rats was conducted to investigate a mild insult, sensitive parameter model in contrast to a severe insult, severe damage model of brain resuscitation. Up to now, the latter approach, which causes neuropathologic changes and neurological abnormalities, has not provided unequivocal data on pharmacological measures to ameliorate post-anoxic brain damage, because of logistical difficulties and many extracranial complicating factors. As tracheotomy and oral intubation in rats proved impractical in studies on recovery from asphyxia, transtracheal jet ventilation was tested in 14 rats as a measure for effective prolonged and reversible control of airway and ventilation. ⋯ The asphyxiated rats showed hyper-excitability for at least 2 weeks. The existence of abnormal behavior during recovery from mild anoxic-ischemic insults to the brain provides parameters for evaluation of therapies of the post-resuscitation disease in a model without the difficulties encountered in models with severe insults, which made post-insult intensive care necessary. The mild insult, sensitive parameter model is promising and further work in this direction is indicated.