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?

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

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

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

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

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

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

The rate of failure of the energy supply Signup and view all the answers

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

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

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

Irreversible membrane failure Signup and view all the answers

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

Rate of energy supply failure Signup and view all the answers

What is the central event that occurs during cerebral ischemia?

Energy failure Signup and view all the answers

What ion gains entry into the cytosol ?

Ca2+ Signup and view all the answers

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

Proteases Signup and view all the answers

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

Uncontrolled increase in cytosolic Ca2+ levels Signup and view all the answers

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

Glutamate Signup and view all the answers

What type of injury is initiated by excessive glutamatergic activity?

Excitotoxicity 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?

Generation of superoxide free radicals 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?

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

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

peroxynitrite Signup and view all the answers

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

Acceleration of anaerobic glycolysis Signup and view all the answers

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

Peroxynitrite Signup and view all the answers

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

[NAD+] Signup and view all the answers

What is a characteristic feature of necrotic neuronal death?

Presence of acidophilic cytoplasm Signup and view all the answers

Which molecule is released into the cytoplasm from injured mitochondria ?

Cytochrome c Signup and view all the answers

What limits injury to surrounding neurons in apoptotic neuronal death?

lack of a substantial inflammatory response to apoptotic death Signup and view all the answers

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

Formation of apoptotic bodies Signup and view all the answers

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

Cleaves essential protein substrates for DNA repair Signup and view all the answers

What initiates the formation of an apoptosome during apoptosis?

Interaction of APAF with procaspase-9 Signup and view all the answers

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

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

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

Delayed neuronal death after the initial insult Signup and view all the answers

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

It shows that neuroprotective efficacy may not be sustained over time. 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?

A potential for further neuronal injury. Signup and view all the answers

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

They undergo delayed death. Signup and view all the answers

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

Most neurons undergo rapid death with severe ischemia. Signup and view all the answers

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

To determine the efficacy of the intervention beyond the acute phase of injury Signup and view all the answers

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

Thrombolysis 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?

Thrombolysis with iv alteplase 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?

4.5 hours Signup and view all the answers

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

Recent intracranial or spinal surgery 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?

Mechanical thrombectomy 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?

Narrow window for thrombolysis Signup and view all the answers

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

Mismatch between ischemic and infarcted tissue indicating salvageability 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?

Improved neurologic outcome following thrombectomy Signup and view all the answers

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

Normalization of systemic pH 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?

Induction of mild hypothermia Signup and view all the answers

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

Reduced incidence of mortality Signup and view all the answers

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

Over a period of 8 hours Signup and view all the answers

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

Similar to the control group Signup and view all the answers

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

Improved neurologic outcome and survival 6 months after cardiac arrest Signup and view all the answers

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

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

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

Excessive cerebral edema Signup and view all the answers

what is considered effective to control intracranial hypertension ?

osmotherapy Signup and view all the answers

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

barbiturates Signup and view all the answers

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

improve CBF but not neurologic outcome Signup and view all the answers

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

Indicated no overall benefit in neurologic outcome Signup and view all the answers

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

prevention and treatment of seizures 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.