The aim of the PCA is to allow you to control your pain safely and effectively.
The greatest benefit is that you do not need to wait for anyone to bring painkillers to you. As soon as you press the button, you are given a small dose of strong painkiller.
The PCA pump is safe, as it cannot give you too much painkiller. A special timer stops the pump from working for a few minutes after it is pressed. The anaesthetic doctor (anaesthetist) will decide how long this should be and tell you. It is usually 5 minutes. During this time pressing the button does not work. This is called a ‘lockout’. This stops you from getting too much of the drug in the pump. After the lockout, the pump will work again when pressed.
It is better to get small but frequent doses of painkiller than an injection into a muscle. The amount of painkiller in your bloodstream is better controlled. This means that you are less likely to feel nausea and vomit. You should also be less sleepy.
The PCA pump means that you do not have repeated injections to give pain relief.
The nurses benefit as they have more time to do other things around the ward.
Are there any alternatives?
There are several alternatives to a PCA. These are:
Intramuscular injection - The most common way to give strong painkillers before PCA was by injection. A dose of drugs such as morphine can be injected into your muscle. This is usually into your backside (buttock). The injection is released over a period of time. It reduces pain for about 4 to 6 hours. It will be a little uncomfortable to have the injection. The injection can be repeated if your pain comes back and is still severe.
Epidural - It may be suitable to perform an epidural, which means placing a needle into an area close to the spinal canal. This method involves threading a plastic tube through the needle, which allows medications to be given down the tube over time. This allows pain relief to be given for several days. The tube lies just outside the covering of the spinal cord, which is called the dura, hence the name epidural. This method is only good for injuries or operations on the lower part of the body. Generally the parts of the body below the breastbone can use an epidural for pain relief. There is another leaflet that describes this in detail.
Suppositories - A suppository is a soft pellet of painkiller. It is inserted into your back passage (rectum). The pellet is gently pushed in through your anus. It gradually dissolves over a period of hours and is absorbed into your bloodstream. This is safe and effective. The suppositories may be put in while you are asleep during a general anaesthetic. You will then know nothing about it. However, the anaesthetist will warn you of this and get your permission before the operation. Suppositories are never essential.
Tablets - It is possible to have tablets to control your pain. To use these your stomach must be working. After minor surgery you may be able to take tablets within a few hours. This may be the easiest way to control your pain.
After some major operations the stomach and intestines stop working, often for several days. If you are feeling nauseous and vomiting, then the tablets will come back out and be useless. Once your stomach is working then tablets can be used. Even strong painkillers such as morphine can be given as a tablet or a liquid to be taken by the mouth (orally).
Who should have it done?
General reasons for having a PCA, are listed below:
Who should not have it done?
If you are unwilling to have a PCA, then other methods of controlling your pain can be used.
Additionally there are specific medical situations when a PCA should not be used and these are as follows:
Allergy to the strong painkillers used in the PCA pump.
If you are not able to press the button well. People with bad arthritis may have a problem squeezing the button, so the PCA may not work for them.
Author: Dr Sean White FRCA. Consultant in pain and anaesthesia
© Dumas Ltd 2006