From the Guidelines
Determining brain death in patients on Extracorporeal Membrane Oxygenation (ECMO) should be based on a multimodality approach, including clinical/neurological examination, electrophysiological tests, and neuroimaging, as recommended by the Extracorporeal Life Support Organization consensus guidelines 1. This approach is crucial because it considers the complexities and confounding factors associated with ECMO, such as the potential for hypothermia and the effects of sedatives and neuromuscular blockers on neurological assessment.
When assessing brain death in ECMO patients, several key factors must be considered:
- The patient must be comatose with no evidence of brainstem reflexes.
- An apnea test must be performed, taking into account the need for pre-oxygenation and temporary adjustment of ECMO settings to ensure that the patient's condition is not confounded by the life support technology.
- The use of ancillary tests such as cerebral angiogram or nuclear scan (radionuclide brain scan) is recommended when the apnea test is challenging 1.
- It is essential to exclude confounding factors and to follow official recommendations, guidelines, and laws of the specific country regarding the determination of brain death.
The importance of a multidisciplinary approach, including frequent meetings and goals of care discussions with the patient surrogate, cannot be overstated, as it ensures that the patient's preferences and values are respected throughout the process 1. This comprehensive strategy helps in making informed decisions about the continuation or withdrawal of ECMO support, balancing the potential benefits against the risks and the patient's quality of life.
From the Research
Determining Brain Death in ECMO Patients
- The determination of brain death in patients on Extracorporeal Membrane Oxygenation (ECMO) is a complex process that requires careful consideration of various factors, including the patient's clinical condition, the ECMO settings, and the availability of ancillary tests 2, 3.
- Apnea testing is a crucial component of brain death determination, but it can be challenging to perform in patients on ECMO due to the risk of hypoxia and hypercarbia 3, 4.
- Several studies have reported successful determination of brain death in pediatric and adult patients on ECMO, using modified apnea testing protocols that involve adjusting the ECMO settings to achieve hypercarbia while maintaining oxygenation and hemodynamic stability 2, 4.
- The use of transcranial Doppler (TCD) has been proposed as a useful adjunct to clinical examination and apnea testing in determining brain death in patients on ECMO, as it can provide information on cerebral blood flow and help confirm the diagnosis of brain death 5.
- A clinical overview of brain death determination highlights the importance of considering special circumstances, such as ECMO support, in the diagnosis of brain death, and emphasizes the need for a comprehensive approach that includes clinical examination, apnea testing, and ancillary tests 6.
Apnea Testing in ECMO Patients
- Apnea testing can be performed in patients on ECMO by decreasing the sweep gas flow and increasing oxygen delivery through the membrane, allowing for a safe and effective assessment of brain death 4.
- The protocol for apnea testing in ECMO patients involves decreasing the ECMO sweep gas flow to 1 L/min and increasing oxygen delivery to 100% during the apnea test, which allows for an increase in PaCO2 without decreasing PaO2 4.
- The use of an oxygenated apnea test on ECMO using continuous positive airway pressure (CPAP) through the ventilator or anesthesia bag, with an inline manometer and an end-tidal CO2 device, has been proposed as a reliable method for determining brain death in adult patients on ECMO 3.
Ancillary Tests for Brain Death Determination
- Transcranial Doppler (TCD) is a useful adjunct to clinical examination and apnea testing in determining brain death, as it can provide information on cerebral blood flow and help confirm the diagnosis of brain death 5.
- Other ancillary tests, such as electroencephalography (EEG) and angiography, may also be used to support the diagnosis of brain death, but their use may be limited by logistical and technical considerations 5, 6.