Which of the following is not an exclusion of brainstem death

Exclusion of brainstem death : When the patient under effect of drug overdose When the core temperature is below 35 degree Celsius When the patient is suffering from severe metabolic/ endocrine disturbance Preconditions for the diagnosis for Brain stem death : 1. Patient must be deeply comatose2. Patient must be maintained on a ventilator3. Cause of the coma must be known