Editor's note: This is the first of a new monthly feature from the Harvard Ambulance Service. It will include updates on the activities of the ambulance service as well as vital information on health and emergency care.

Facts and figures from 2011:

• Active members: 68
• Total number of hours on call: 24,140
• Average number of EMTs (emergency medical technicians) on call at all times: 3
• Total runs: 294
• ALS (advanced life support) is called on a third of our runs
• Timing of calls: 18 percent were between midnight and 8 a.m., 50 percent were between 8 a.m. and 4 p.m., and 32 percent were between 4 p.m. and midnight.

How to recognize a stroke

A stroke happens when the blood to the brain is reduced and therefore the oxygen supply is cut off. There are several different types of strokes, including the main types: ischaemic stroke, with a blocked artery in or leading to the brain; hemorrhagic stroke, with a burst blood vessel in the brain; and a transient ischaemic stroke, which is a mini-stroke caused by lack of blood supply to the brain.

Strokes are most common in people over the age of 65; however, strokes in younger people are more common than you may think. Every 10 years after the age of 55, one's risk for having a stroke doubles. Other than age, the factors that increase the likelihood of a stroke include smoking, high blood pressure, family history, high cholesterol, obesity, and diabetes.

Stroke is the third leading cause of death in the United States and the number one cause of serious, long-term disability. For this reason, it is important to be able to recognize a patient suffering from a stroke so that the necessary care can be provided. The signs of a stroke can be remembered using the acronym FAST.

• Facial droop: One side of the patient's face may appear to droop lower than the other half. Ask the patient to show his teeth; only one side of his mouth may move.
• Arm: Have the patient close her eyes and hold both of her arms straight out in front of her. If one arm falls, there is a chance the patient is suffering from a stroke.
• Slurred speech: A stroke victim may slur his words together while speaking in a way that may seem as if he has been drinking alcohol.
• Time: The timing of a stroke is very important in regards to the medication that can be given to save the victim. Be sure to document the time as soon as you notice any of the signs of a stroke and call 911.

Another important, tell-tale sign of a stroke is the presence of uneven pupil dilation. On the side of the brain where the stroke is occurring, there will be increased pressure that will cause that pupil to be more dilated than the pupil on the opposite side.

What can you do for a stroke victim?

As soon as you have any speculation that someone is having a stroke, you must call 911 right away. While you are waiting for help to arrive, you should make sure that the patient maintains a clear airway and can breath easily. Try to make note of what you observe, such as what medications the patient has taken, how long the stroke lasts, and what the patient was doing before the stroke. Do not offer the patient food or water as it may block the airway. Most importantly, stay calm and comfort the patient.