Cerebral perfusion and metabolism in resuscitated patients with severe post-hypoxic encephalopathy

Anoxic Injury-Associated Cerebral Hyperperfusion Identified with Arterial Spin-Labeled MR Imaging

“…With 12 of 16 normocapnic patients in our series dying within 4 weeks of perfusion imaging, it is clear that the natural course of anoxic-related cerebral injuries is devastating. 2,35,36 Of the patients who survived in our series (n ϭ 4), 1 patient was probably hypercapnic and returned to baseline function. The remaining survivors had unfavorable outcomes, including persistent vegetative state, severe encephalopathy, and profound short-term memory difficulties similar to those reported previously.…”

“…17,27,28 Little human research exists regarding the effect of global anoxia on autoregulation. 4,20,[29][30][31][32][33][34][35][36][37] Animal models have shown a loss of cerebral vascular resistance in the postanoxic state resulting in uncontrolled hyperperfusion. [38][39][40][41][42] Cerebral blood volume has been shown to increase with loss of autoregulation secondary to ischemia, but no large studies have demonstrated a similar relationship for CBF.…”

“…43 Relative hyperperfusion has been shown in the thalamus, cerebellum, and occipital lobes with O-15 PET imaging in resuscitated patients; however, this method does not quantitate flow. 36 Schaafsma et al 36 believed this hyperperfusion was secondary to a "postanoxic disturbance of autoregulation." We believe that a similar loss of autoregulation accounts for the cerebral hyperperfusion seen in our ASL patient series.…”

“…We believe that a similar loss of autoregulation accounts for the cerebral hyperperfusion seen in our ASL patient series. 20,36,38 Xenon-CT perfusion has been used to evaluate CBF after cardiac resuscitation. A study by Cohan et al 4 showed an increase in global whole-brain CBF by up to 300% in nonsurviving patients.…”

“…The remaining survivors had unfavorable outcomes, including persistent vegetative state, severe encephalopathy, and profound short-term memory difficulties similar to those reported previously. 36 Future trials with animal models may elucidate treatment strategies to preserve function and improve outcome. Recent animal models and clinical studies of global ischemia have shown promising neuroprotective effects of mild-to-moderate therapeutic hypothermia.…”