A stroke occurs when a blood clot blocks a blood vessel or artery, or when a blood vessel breaks and interrupts blood flow to an and bleeding occurs into an area of the brain. Every stroke is different.
ETA Chlorophyll works on the Liver and probably works a little. No it really doesn't, you are not a plant. Tea will oxygenate the blood. No it won't Also don't do as someone else said and drink liquid oxygen, that's really not a good idea.
During the assessment it's likely that the amount of oxygen in your blood will be measured by taking a blood sample from your earlobe or wrist, or attaching a sensor to your finger (a pulse oximetry test). You may also be asked to breathe into a device called a spirometer during a spirometry test.