Patient Care Following A Cardiac Arrest

Question 1

A 49-year-old male patient is admitted following a cardiac arrest in the community. He underwent three cycles of CPR and shocks for a VF rhythm. The post-ROSC ECG demonstrates widespread ST segment elevation. He is intubated and ventilated and admitted to intensive care following cardiac catheterisation, during which a clot was removed from the left anterior descending coronary artery.

What are the key aspects for post-resuscitation care in this patient?

Answer 1

• Take a full collateral history and carry out a systematic examination. Update the family and determine the general wishes of the patient, including advanced statements or directives.
• Continue treatment for the likely cause of the cardiac arrest (myocardial infarction) with close cardiology team involvement, including appropriate medication as directed.
• Optimise ventilatory and haemodynamic strategies with appropriate monitoring to ensure favourable physiology to minimise secondary brain injury and cardiac work.
• Ensure neuroprotective measures including treatment of pyrexia and seizures and blood glucose control. Targeted temperature management should be discussed.
• Consider further investigations when the patient is stable e.g. CT head, EEG and echo.

Question 2

How is targeted temperature management carried out?

Answer 2

• Ensure continuous core body temperature monitoring e.g. oesophageal temperature probe.
• The patient should be well sedated and can be paralysed to prevent shivering and other involuntary movements.
• Surface cooling measures e.g. ice packs, wet towels or specific proprietary devices.
• Specialised intravascular systems can be used to monitor and finely control core temperature.

Question 3

What is the “post-resuscitation” syndrome?

Answer 3

• The post-resuscitation syndrome consists of four elements that contribute to further pathological responses after cardiac arrest:

1. Secondary brain injury.
2. Cardiac dysfunction/stunning.
3. Systemic ischaemia and reperfusion injury.
4. Continuation of the pathological process that triggered arrest.

Question 4

The patient remains intubated and ventilated for 2 days.

How should prognostication take place?

Answer 4

• Neurological prognostication should take place at least 72hours following the cardiac arrest to allow for targeted temperature management to take place, and for potential reversibility of ongoing pathological processes.
• Prior to prognostication, restoration of normal physiology should be attempted as best as possible to allow for an accurate diagnosis.

Clinical examination:
* Sedation hold with regular neurological assessment including GCS.

• Poor prognostic indicators include: absence of ocular reflexes (pupillary, corneal blink), absent/abnormal motor response and
  ongoing seizure activity.

Investigations:
* CT head looking for indicators of hypoxic brain injury.

• EEG – burst suppression and seizure activity are negative prognostic
  indicators.
• Somatosensory evoked potentials (specifically N20s).
• Blood markers of tissue damage e.g. neuron-specific enolase
  levels>33 μg/L on days 1–3 are strongly associated with a poor outcome.

Question 5

The patient remains intubated and ventilated for 2 days. How should prognostication take place?

Continued…?

Answer 5

If you are asked further about somatosensory-evoked potentials, it should be noted that:

• Bilaterally absent short latency peaks (N20 peaks) have a 100% predictive value for poor outcome (death/severe disability) with a false positive rate of nearly 0% and narrow confidence intervals.
• SSEP is the most reliable test to predict poor outcomes in this patient group but does not predict good outcomes.
• The pre-test probability for poor outcome is essential; use the test only for patients who remain unconscious following a hypoxic ischaemic insult. The test has been validated for use as early as 24hours after a cardiac arrest.
• SSEP testing is not affected by sedatives, analgesics, paralysing agents or metabolic insults.

Question 6

The CT scan suggests widespread ischaemia effects likely representing severe hypoxic brain injury in this context.

What criteria need to be met before brainstem death testing can take place?

Answer 6

• No likely reversible cause of apnoea e.g. biochemical/metabolic causes, residual sedatives or neuromuscular blockade, hypothermia.
• Stable physiology prior to undertaking the tests.
• Testing should be performed by two doctors familiar with the process,
  fully registered with the General Medical Council for at least 5 years,
  with at least one consultant.
• There should be an identified precipitating cause of brainstem death.