Frederick CPR Instruction

Sprains and strains are simply abnormal stretching or tearing of the ligaments or tendons around a joint.  Ligaments attach bones to bones, and tendons attach muscles to bones.  These tissues do not receive a lot of blood flow, so healing can be delayed to the structures. 

The good news is that tendons and ligaments are designed to stretch and contract- so a simple sprain, where the ligament is simply stretched too far, can return to normal shape and function in a matter of days.  More complex sprains, where tissues are torn, can take significantly longer, or may even require surgical repair. 

No matter what grade of sprain or strain, initial treatment revolves around R.I.C.E. therapy, designed to reduce the swelling and inflammation around the area, so that it can feel better faster, and heal faster. 

R- Rest.  Rest the injured part  during the initial 2-3 days.  Thereafter, gentle stretching is often recommended for simple sprains or strains

I- Ice.  Ice directly reduces swelling at the site

C- Compression.  An Ace type bandage not only provides support, but also drives swelling away.

E- Elevation.  Again, the focus here is to reduce swelling.


Additionally, Ibuprofen is often recommended for a few days, as this anti-inflammatory drug not only helps pain, but acts internally to reduce inflammation.  


management of sprains and strains and application of bandages are covered in AHA's First Aid course.

Author:  Scott Carpenter

We were recently asked how many shocks an AED could deliver on one battery. 

There are a couple of variables to consider, such as- if the AED is monophasic or biphasic (referring to current and whether it is an escalating shock or a fixed energy shock), the patient's transthoracic impedance (variables of patient chest size), and patient's response to shocks. Therefore, it's good to know the 'use time, or general amount of shocks that can be delivered' with a specific AED and it's battery component.

Typically, the batteries used for AED are long life Lithium batteries which last approximately 4 years when the AED is in stand-by mode. Each manufacturer's specifications are different, but generally, when the AED is in use (with fresh Lithium batteries), that equates to up to 150-300 shocks or 720 minutes of use time.

So, really, it depends upon the manufacturer of the specific AED you are using, and of course- the manufacturers can provide specific information.

In any case, with a standard AED, it will be able to deliver all the shocks needed during such an event.

How does nitroglycerin decrease the pain of acute angina? perhaps not in the way that you would expect.

At rest, the heart uses almost all of the oxygen delivered to it via it's own vessels, the coronary arteries.  When the heart is subjected to an increased workload, these vessels dilate in response.  If a vessel is occluded with plaque or a clot, it will be unable to supply the blood and oxygen needed, and pain and tissue damage can result.

The key determinants of myocardial (heart muscle) oxygen demand are myocardial contractility, heart rate, and very importantly- myocardial wall tension.


Nitroglycerin is, at typical doses, a VENOUS dilator.  By decreasing venous return to the heart (preload) nitroglycerin decreases the filling pressure of the heart, decreasing myocardial wall tension, force of contraction, and by extension, myocardial workload and oxygen demand of the stressed tissue.   Nitroglycerin only minor effect on arteries or arterioles at usual doses, although a high dose drip (greater than 40mcg/min) can have artery dilating effects. So, nitro does not dilate atherosclerotic arteries to allow blood to flow around any clots or occlusions in the arterial system of the heart.  When nitroglycerin has been injected directly into a blocked coronary artery, it has not relieved pain!  In other words, nitroglycerin eases coronary chest pain by reducing the heart's oxygen needs, NOT by providing more oxygen supply.  Although blood pressure can drop with nitroglycerin, it can be minimized with the patient lying down.

There are drugs that selectively dilate arterioles, (reducing afterload) like hydralazine and minoxidil, which are very powerful at reducing blood pressure.  These drugs are NOT used in acute anginal pain, because, as blood pressure drops with them, there is reflex tachycardia and increased myocardial contractility,  greatly increasing the workload and oxygen demand of the heart.  Although the drop in blood pressure with nitroglycerin can also cause tachycardia, it is generally milder, and often eliminated with a beta blocker medication to prevent it.