Context: The Supreme Court of India has agreed to examine a medical plea alleging that the apnoea test, used as a primary assessment for brain death in Kerala, may be medically inconclusive and potentially dangerous.
About The Apnoea Test:
What it is?
- The apnoea test is a mandatory clinical procedure used to determine if a patient is brain-dead (death by neurologic criteria). It specifically checks if the brainstem—the part of the brain that controls automatic functions like breathing—is still functioning.
Aim:
- The primary goal is to see if the body can trigger a breath on its own when carbon dioxide (CO2) levels in the blood rise to a specific high point.
- If the patient does not attempt to breathe even when CO2 is very high, it indicates that the brainstem has permanently lost its function.
Key Features:
- The Challenge: Doctors temporarily stop the ventilator (the breathing machine) to let CO2 build up in the patient’s body. High CO2 acts as a natural alarm that tells a healthy brain to take a breath.
- Pre-Oxygenation: Before starting, the patient is given 100% oxygen for 10 minutes to ensure they have enough reserve oxygen while they aren’t being actively ventilated.
- The Threshold: Doctors look for a specific CO2 level (usually ≥ 60 mmHg) and an acidic blood pH (below 7.30). At this stage, a living brain must trigger a gasp or chest movement.
- Visual Check: Medical staff watch the chest and abdomen closely for any sign of a spontaneous breath. If no movement is seen once the CO2 target is hit, the test is positive for brain death.
- Safety Stops: The test is immediately stopped if the patient’s blood pressure drops too low or if oxygen levels in the blood fall below 85%.
Implications:
- Organ Donation Prerequisite: A positive apnoea test confirms absence of brainstem function, legally enabling organ retrieval.
- Conclusive Evidence: It is treated as a critical test to establish irreversible coma and certify brain death.
- Potential Harm: Ventilator withdrawal increases CO₂ and acidosis, which may further damage already compromised brain tissue.
