Post-Cardiac Arrest Management – Time to Say Goodbye to Self Fulfilling Prophesy
Robert Rosenthal defined the Pygmalion effect as “the phenomenon whereby one person’s expectation for another person’s behavior comes to serve as a self-fulfilling prophecy” (1)
2015 ILCOR guidelines (2) seem to sway away from self-fulfilling prophesy approach in prognostication post cardiac arrest patients.
Successful return of spontaneous circulation (ROSC) is the first step towards the goal of complete recovery from cardiac arrest. The complex pathophysiological processes that occur following whole-body ischemia during cardiac arrest and the subsequent reperfusion response during CPR and following successful resuscitation have been termed the post-cardiac arrest syndrome.
The post-cardiac arrest syndrome comprises post-cardiac arrest brain injury, myocardial dysfunction, the systemic ischemia / reperfusion response, and the persistent precipitating pathology. Post-cardiac arrest brain injury manifests as coma, seizures, myoclonus, varying degrees of neurocognitive dysfunction and brain death. Post-cardiac arrest brain injury may be exacerbated by microcirculatory failure, impaired auto regulation, hypotension, hypercarbia, hypoxemia, hyperoxaemia, pyrexia, hypoglycaemia, hyperglycaemia and seizures. Significant myocardial dysfunction is common but typically starts to recover by 2–3 days, although full recovery may take significantly longer. The whole body ischemia / reperfusion of cardiac arrest activates immune and coagulation pathways con-tributing to multiple organ failure and increasing the risk of infection
Depending on the cause of the arrest, and the severity of the post-cardiac arrest syndrome, many patients require multiple organ support and the treatment they receive during this post-resuscitation period influences significantly the overall outcome and particularly the quality of neurological recovery.
Overall aim is to provide the treatment to optimise haemodynamic, respiratory and metabolic variables, together with targeted temperature management. Continuous monitoring and regular clinical assessment and re-evaluation of treatment goals are part of this process of care.
Key Recommendations –
- Neurologic state will dictate need for airway protection and ventilation but in general patients admitted to ICU with ROSC require initial airway support.
- Hypoxemia and hypercarbia both increase the likelihood of a further cardiac arrest and may contribute to secondary brain injury and should be avoided.
- Titrate the inspired oxygen concentration to maintain the arterial blood oxygen saturation in the range of 94% -98%. It is reasonable to adjust ventilation to achieve normocarbia and to monitor this using the end-tidal CO2 and arterial blood gas values.
- Post-resuscitation myocardial dysfunction causes haemodynamic instability, which manifests as hypotension, low cardiac index and arrhythmias. Vasopressor support, noradrenaline with or without dobutamine, and fluid is usually the most effective treatment.
- Treatment is guided by blood pressure, heart rate, urine output, rate of plasma lactate clearance, and central venous oxygen saturation.
- Cardiac output monitoring may help to guide the treatment in the haemodynamically unstable patient.
- Serial echocardiography may also be used, especially in haemodynamically unstable patients.
- Hemodynamic goals (e.g., mean arterial pressure [MAP], systolic blood pressure [SBP]) should be considered during post resuscitation care and as part of any bundle of post-resuscitation interventions.
- Routine prophylactic use of anti-arrhythmic agents is discouraged.
- It may be reasonable to continue an infusion of an antiarrhythmic drug that successfully restored a stable rhythm during resuscitation (e.g. lignocaine 2-4 mg/min or amiodarone 0.6 mg/kg/hr for 12-24 hours).
- Routine seizure prophylaxis in post-cardiac arrest patients is not indicated, however treatment of seizures is strongly recommended.
- Standard glucose management protocol in the unit should be followed for all patients with ROSC after cardiac arrest aiming for normoglycemia
Targeted Temperature Management –
This is one of the most important aspects of post-resusctation care.
- Targeted temperature management should be used for ALL cardiac arrests ( in-hospital and out of hospital, shockable and non-shockable rhythm) patients who remain unresponsive after ROSC, unless there is a contraindication or extremely poor prognosis is expected.
- Active temperature control is required to achieve and maintain the temperature in the range of 32-36 degree celcius.
- Maintain the targeted temperature for at least 24 hours.
- The practical application of TTM is divided into three phases: induction, maintenance and rewarming.
- External and/or internal cooling techniques should be used to initiate and achieve the targeted temperature, promptly within 4 hours of arrival in the intensive care unit.
- Patients who arrive in intensive care unit with a temperature less than 32◦C, a practical approach is to let them rewarm spontaneously and to activate a TTM-device when they have reached 36ºC.
- After 24 hours of TTM, rewarming should be achieved by 0.25-0.5ºC /hour.
- Monitor carefully for side effects of hypothermia such as electrolyte imbalance, glucose intolerance, increased infection risk, arrhythmias, coagulopathy & rebound hyperthermia.
- Prevention & treatment of fever in persistently comatose patient should be considered even after completion of TTM.
Often clinicians tend to rush to withdraw tretment based on neurological exam findings in first 24hours. This predominently includes myoclonic jerks. Myoclonic jerks in isolation are not a good prognostic indicator and shouldn’t be used as a sole criterion for withdrwal of treatment. Instead Multi-Modal Apprach to prognositication should be used. This involves History, Examination & Investigations.
Key features in history s/o possible worse prognosis are –
Delay in effective bystander CPR ( >8 min), Prolonged CPR ( >20min) and multiple co-morbidities/ poor baseline functionality.
- Thorough neurologial exam must be performed only after ruling out all possible confounders such as sedation, sepsis or any other metabolic cause that can lead to encephalopathy.
- Neurophysiological investigation such as EEG/SSEP, should be considered to rule out underlying seizure activity. Interpreting these investigations in the context of hypoxic brain injury requires expertise and early referral to neurologist should be considered in order to make a collborative decision for withdrawl.
- In general prognostication should not be carried out in comatose post cardiac arrest survivors in first 72 hours unless there are exceptional circumstances.
A careful clinical neurological examination remains the foundation for prognostication of the comatose patient after cardiac arrest. The process of brain recovery following global post-anoxic injury is completed within 72h from arrest in most patients. In a recent observational study, 94% of patients awoke within 4.5 days from rewarming and the remaining 6% awoke within ten days.(3) Even those awakening late, can still have a good neurological outcome.
Therefore, when dealing with uncertin outcome, clinicans should allow more time for neurological recovery rather self fulfilling thier prophesy by withdrwaing the life sustaining treatment.
- American Psychologist 58.3 [November 2003], p. 839.