chapter 11. quiz 7. pathology and Considerations for Complete Global Ischemia (Cardiac Arrest)
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Questions and Answers

What happens to neuronal function when cerebral blood flow (CBF) decreases below normal levels?

  • It deteriorates progressively rather than abruptly. (correct)
  • It remains unaffected.
  • It stops completely.
  • It deteriorates abruptly.
  • At what level of CBF does the brain show indications of potentially irreversible membrane failure?

  • 6-10 mL/100 g/min (correct)
  • 1-5 mL/100 g/min
  • 30-40 mL/100 g/min
  • 15-20 mL/100 g/min
  • What is the term used for brain regions where neuronal dysfunction is temporarily reversible but neuronal death will occur if blood flow is not restored?

  • Penumbra (correct)
  • Cerebral infarction
  • Hypoperfusion zone
  • Ischemic core
  • At what CBF level does the brain show isoelectric cortical EEG?

    <p>15 mL/100 g/min</p> Signup and view all the answers

    What are the consequences of decreased CBF to approximately 10-15 mL/100 g/min?

    <p>Progressive deterioration in energy supply leading to membrane failure.</p> Signup and view all the answers

    What level of CBF marks a time course of slow neuronal death over hours rather than minutes?

    <p>10-15 mL/100 g/min</p> Signup and view all the answers

    What is the key difference between complete cerebral ischemia and incomplete cerebral ischemia?

    <p>The rate of failure of the energy supply</p> Signup and view all the answers

    Why does incomplete cerebral ischemia show greater tolerance compared to complete global ischemia?

    <p>Residual blood flow can deliver enough oxygen for ATP generation</p> Signup and view all the answers

    During normothermic complete cerebral ischemia, what occurs within minutes that is catastrophic?

    <p>Irreversible membrane failure</p> Signup and view all the answers

    What factor contributes to the apparent tolerance for focal or incomplete ischemia?

    <p>Rate of energy supply failure</p> Signup and view all the answers

    What is the central event that occurs during cerebral ischemia?

    <p>Energy failure</p> Signup and view all the answers

    What ion gains entry into the cytosol ?

    <p>Ca2+</p> Signup and view all the answers

    Which enzyme system requires Ca2+ as a cofactor for activation?

    <p>Proteases</p> Signup and view all the answers

    What initiates the activation of various cellular processes contributing to injury during excitotoxicity?

    <p>Uncontrolled increase in cytosolic Ca2+ levels</p> Signup and view all the answers

    Which neurotransmitter is released in massive quantities into the synaptic cleft during ischemia?

    <p>Glutamate</p> Signup and view all the answers

    What type of injury is initiated by excessive glutamatergic activity?

    <p>Excitotoxicity</p> Signup and view all the answers

    What can lead to lipid peroxidation and membrane injury during the metabolism of arachidonic acid to prostaglandins and leukotrienes?

    <p>Generation of superoxide free radicals</p> Signup and view all the answers

    Which enzyme participates in DNA repair but can lead to energy failure when its activity is excessive due to DNA injury?

    <p>Poly–adenosine diphosphate [ADP]–ribose polymerase (PARP)</p> Signup and view all the answers

    In response to mitochondrial injury, what type of radicals can be generated along with superoxide free radicals?

    <p>peroxynitrite</p> Signup and view all the answers

    What effect does an increased preischemic serum glucose level have on the process of anaerobic glycolysis during ischemia?

    <p>Acceleration of anaerobic glycolysis</p> Signup and view all the answers

    What is the killer substance used by macrophages that can contribute to neuronal damage?

    <p>Peroxynitrite</p> Signup and view all the answers

    Which molecule, important for energy metabolism, becomes depleted as a result of excessive PARP activity during DNA repair?

    <p>[NAD+]</p> Signup and view all the answers

    What is a characteristic feature of necrotic neuronal death?

    <p>Presence of acidophilic cytoplasm</p> Signup and view all the answers

    Which molecule is released into the cytoplasm from injured mitochondria ?

    <p>Cytochrome c</p> Signup and view all the answers

    What limits injury to surrounding neurons in apoptotic neuronal death?

    <p>lack of a substantial inflammatory response to apoptotic death</p> Signup and view all the answers

    What is the key difference between necrotic neuronal death and apoptotic neuronal death?

    <p>Formation of apoptotic bodies</p> Signup and view all the answers

    During apoptosis, what is the role of activated caspase-3?

    <p>Cleaves essential protein substrates for DNA repair</p> Signup and view all the answers

    What initiates the formation of an apoptosome during apoptosis?

    <p>Interaction of APAF with procaspase-9</p> Signup and view all the answers

    What new understanding about postischemic neuronal injury has more recent data revealed?

    <p>Postischemic neuronal injury is a dynamic process where neurons continue to die for an extended period.</p> Signup and view all the answers

    What contributes to the gradual expansion of cerebral infarction after focal ischemia?

    <p>Delayed neuronal death after the initial insult</p> Signup and view all the answers

    Why does the occurrence of delayed neuronal death have important implications for studies on neuroprotective strategies?

    <p>It shows that neuroprotective efficacy may not be sustained over time.</p> Signup and view all the answers

    What is indicated by evidence of cerebral inflammation even 6 to 8 months after primary ischemia in experimental studies?

    <p>A potential for further neuronal injury.</p> Signup and view all the answers

    What happens to neurons that survive the initial insult with more moderate ischemic insults?

    <p>They undergo delayed death.</p> Signup and view all the answers

    How does the severity of the ischemic insult affect delayed neuronal death?

    <p>Most neurons undergo rapid death with severe ischemia.</p> Signup and view all the answers

    Why is long-term evaluation of a therapeutic intervention important in the context of cerebral infarction?

    <p>To determine the efficacy of the intervention beyond the acute phase of injury</p> Signup and view all the answers

    What is the mainstay in the reduction of brain injury in the setting of acute ischemic stroke?

    <p>Thrombolysis</p> Signup and view all the answers

    What is recommended for patients with acute ischemic stroke when the time from symptom onset to treatment is less than 3 hours?

    <p>Thrombolysis with iv alteplase</p> Signup and view all the answers

    In selected patients, up to how many hours can the window for thrombolysis be extended from the onset of symptoms?

    <p>4.5 hours</p> Signup and view all the answers

    What is a key contraindication to thrombolysis in patients with acute ischemic stroke?

    <p>Recent intracranial or spinal surgery</p> Signup and view all the answers

    Which factor has considerably expanded the window for potential benefit from clot removal in patients with acute ischemic stroke?

    <p>Mechanical thrombectomy</p> Signup and view all the answers

    What has limited the number of patients who may benefit from clot removal in the context of acute ischemic stroke?

    <p>Narrow window for thrombolysis</p> Signup and view all the answers

    What characteristic defines tissue that is amenable to salvage in the context of thrombectomy for acute ischemic stroke?

    <p>Mismatch between ischemic and infarcted tissue indicating salvageability</p> Signup and view all the answers

    What is the primary outcome observed in patients who met the enrollment criteria for the DAWN and DEFUSE 3 trials?

    <p>Improved neurologic outcome following thrombectomy</p> Signup and view all the answers

    What is one of the important therapeutic objectives in patients who sustain a cardiac arrest?

    <p>Normalization of systemic pH</p> Signup and view all the answers

    What is an effective strategy in reducing mortality and morbidity in patients with altered mental status following cardiac arrest?

    <p>Induction of mild hypothermia</p> Signup and view all the answers

    What was the outcome of induction of whole-body hypothermia in neonates with hypoxic-ischemic encephalopathy?

    <p>Reduced incidence of mortality</p> Signup and view all the answers

    How was passive rewarming achieved after inducing mild hypothermia in patients?

    <p>Over a period of 8 hours</p> Signup and view all the answers

    What does the text suggest about the incidence of complications in patients undergoing induced hypothermia?

    <p>Similar to the control group</p> Signup and view all the answers

    What is one of the benefits observed in patients undergoing induced hypothermia post-cardiac arrest?

    <p>Improved neurologic outcome and survival 6 months after cardiac arrest</p> Signup and view all the answers

    Why is maintaining adequate perfusion pressure after cardiac arrest considered important?

    <p>To prevent hypotension from developing which may aggravate the microcirculatory and vasospastic processes</p> Signup and view all the answers

    What is a late phase complication that may occur after cardiac arrest?

    <p>Excessive cerebral edema</p> Signup and view all the answers

    what is considered effective to control intracranial hypertension ?

    <p>osmotherapy</p> Signup and view all the answers

    which of the following is considered ineffective treatment after cardiac arrest ?

    <p>barbiturates</p> Signup and view all the answers

    In a small cohort study, what effect did nimodipine show in patients after cardiac arrest?

    <p>improve CBF but not neurologic outcome</p> Signup and view all the answers

    What was the outcome of the multicenter lidoflazine cardiac arrest study regarding nimodipine administration?

    <p>Indicated no overall benefit in neurologic outcome</p> Signup and view all the answers

    important therapeutic objectives after Complete Global Ischemia (Cardiac Arrest) ?

    <p>prevention and treatment of seizures</p> Signup and view all the answers

    Study Notes

    • Pharmacologic agents to protect the brain from ischemic injury have not been identified.
    • Thrombolysis is the main treatment for reducing brain injury in acute ischemic stroke.
    • Thrombolysis with IV alteplase is recommended within 3 hours of symptom onset.
    • Mechanical thrombectomy has expanded the window for clot removal in acute ischemic stroke.
    • Trials showed improved outcomes in patients undergoing thrombectomy with substantial ischemic tissue.
    • Endovascular treatment eligibility in acute ischemic stroke patients has increased due to recent trials.
    • Anesthesiologist involvement in caring for these patients will significantly increase.
    • The brain is highly vulnerable to energy failure during cerebral ischemia.
    • Neuronal function deteriorates progressively with declining cerebral blood flow.
    • Ischemic penumbra refers to brain tissue with reversible dysfunction but potential for irreversible damage.
    • Energy failure during cerebral ischemia leads to membrane depolarization and excitotoxicity.
    • Excessive glutamatergic activity initiates excitotoxicity and neuronal swelling.
    • Glutamatergic receptors activation leads to calcium influx and cellular injury processes.
    • Free radicals generated during cerebral ischemia contribute to oxidative injury and inflammation.
    • Neuronal death in ischemia can occur through necrosis or apoptosis pathways.
    • Apoptosis in neurons is initiated by the release of cytochrome c from injured mitochondria.
    • Therapeutic goals in ischemic brain injury include maintaining normocapnia and normotension.
    • Induced mild hypothermia has shown effectiveness in reducing mortality and morbidity after cardiac arrest.

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    Description

    Learn about the relevant considerations for complete global ischemia (cardiac arrest), including the importance of maintaining adequate perfusion pressure and the development of intracranial hypertension and cerebral edema post-resuscitation.

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