Physiology and blood chemistry changes of the dying phase

At a glance

• Dying is a final common pathway: whatever the disease, the last days bring falling intake, falling cardiac output, prerenal kidney failure, reduced consciousness and changed breathing.
• Blood chemistry follows predictably: urea and creatinine rise (urea more), sodium rises with free water loss, potassium rises with falling GFR and acidosis, lactate rises with hypoperfusion, and bilirubin, CRP and white cell count often climb. Albumin falls.
• These changes contribute to drowsiness and delirium but are rarely worth correcting. Routine blood tests and observations should stop once dying is recognised.