PREOP - Postoperative Pain Relief

POSTOPERATIVE PAIN RELIEF

(DETAILED VERSION)

It is important to read this information carefully before seeing your anaesthetist. The purpose of this webpage is to help you to understand your postoperative pain relief and to assist you in making informed decisions about your care. It contains a lot of information and you may need to read it more than once. Unfortunately, this amount of information is necessary to have you well informed. If you would like to, it is a good idea to discuss this information with a member of your family or a friend. The information provided is of a general nature and is not comprehensive. It does not take your individual circumstances into account. It cannot replace specific advice given to you by your own anaesthetist. If you have any questions or concerns, or there is anything don't understand, talk to your anaesthetist.

Scattered throughout the body are little sensors; some sense hot, cold, pressure or touch and others sense pain. Pain is a natural response to the presence of damage or disease in the body. The sensors send messages via your nerves to your brain to let you know that something is wrong. Unfortunately, the body cannot distinguish between accidental pains and pain due to surgery. Surgery often, but not always, causes pain. Postoperative pain is the pain felt in the few days immediately following surgery. It is usually due to the surgery, but it may be complicated by pre-existing pain caused by your underlying condition. It is not the same as chronic (long-term) pain and the approach to treating it is different to the management of chronic pain. This section only deals with postoperative pain.

People vary enormously in their perception of and response to pain. Only you can feel your pain and only you can decide whether you need assistance to manage it. There are a number of options available for treating pain following surgery. As the requirement for pain relief is individual, your anaesthetist will devise a plan for managing your postoperative pain using one or more of the available options. Which method or combination of methods is used will depend on the type of procedure you have had, your general health, age, gender, any allergies or sensitivities you may have, previous alcohol or substance abuse, your preference and the availability of each method. A discussion of the way in which all these different methods work to reduce pain is very complex and requires a detailed understanding of biochemistry and physiology; it is outside the purpose of this webpage.

Managing your postoperative pain well prevents needless suffering, improves wound healing and reduces the postoperative risks of: prolonged hospital admission; chronic pain; DVT (blood clots in the leg); pulmonary embolus (blood clots in the lungs); pneumonia and heart complications including ischaemia (lack of oxygen), heart attack and abnormal heart rhythms.

While you are in hospital, your anaesthetist oversees your postoperative pain management. Nurses in recovery and on the ward assist in monitoring your pain and some hospitals have dedicated Pain Teams, usually run by the Anaesthetic Department. In Public Hospitals, Hospital Medical Officers will often take over your pain management, once you are on the ward. Nursing staff will ask you about your pain while you are in hospital. They commonly ask you to score your pain out of 10, where 0 is no pain and 10 is the worst pain you could ever imagine; but there are a number of other tools that are also used to measure pain. There are no right or wrong answers. Remember, you are the only person who can feel your pain and the nurses rely on you to let them know how you feel. If your pain relief is not adequate, let the staff know. You don't need to wait for them to ask. Frequency or doses can sometimes be increased or different methods used to keep you comfortable.

Following surgery it is common for the area of the operation to be numb, rather than sore. This is because it is common for your surgeon or anaesthetist to use local anaesthetic at the operation site during the operation to reduce postoperative pain. While local anaesthetic reduces your need for additional pain relief at first, when the local anaesthetic starts to wear off, your requirement for other pain relief may increase.

Your anaesthetist will usually give you the first dose of pain relief before or during the operation to make you comfortable when you first wake up.

It is important to understand that any medication may cause an allergic reaction. If you have any known allergies, tell your anaesthetist before your operation, so that medications you are allergic to can be avoided. In particular, the same drug can have a number of different names and you may not recognise them all, but your anaesthetist will. It is possible to be allergic to a medication and not know. If you develop itching, rash, difficulty breathing or swelling around your face, do not take any more medication and contact your doctor.

It is important to understand that all medications have side effects and the risk of complications. Some of these may be serious. The most common side effects are discussed below, but the discussion is not comprehensive. If you require more information, talk to your doctor.

The following are methods of postoperative pain relief commonly used in Australia.

These are the simplest forms of pain relief and are the easiest to manage at home. Oral medications are available as mixtures, tablets or capsules. It is usual to give children mixtures. It is important that you carefully follow the directions you are given for taking oral pain relief at home. The amount or dose of medication that you need to take depends on your age and weight and your doctor will let you know how much you need to take. If you don't understand the directions, ask. Your anaesthetist, surgeon or nurse will be happy to explain.

A number of brand names are mentioned on this webpage. These names have been used as you are more likely to be familiar with the brand names, than with the chemical names of the medications. It does not make any difference which brand you use.

Paracetamol. There are several brands of paracetamol ( Panadol or Panamax are the most commonly recognised names, but they are all the same drug) available over the counter at pharmacies or at supermarkets. Paracetamol works best when taken regularly as directed. This form of pain relief is very safe and effective when taken as directed. It is important not to take more paracetamol than recommended. Taking extra paracetamol will not improve your pain relief and can be bad for you. A healthy adult should not take more than 8 tablets containing paracetamol in 24 hours.

Paracetamol/Codeine. Again there are several brands of paracetamol combined with a small dose of codeine ( Panadeine or Codalgin are the most commonly recognised names). This combination is available over the counter at pharmacies only. This preparation is stronger than paracetamol alone, but also has more side effects. It may make you drowsy and may cause constipation. Do not take more than recommended. Again it will not improve your pain relief and may be bad for you.

The paracetamol/codeine combination is also available with a larger dose of codeine ( Panadeine Forte and Codalgin Forte are the most commonly recognised names). This combination is only available on prescription from pharmacies. It provides better pain relief again, but has even more side effects. It is more likely to make you drowsy and cause constipation and may cause nausea and vomiting. Do not take more than recommended. Again, taking more than the recommended dose will not improve your pain relief and may be bad for you. While Panadeine Forte is a good drug for short-term use immediately after an operation, it should not be taken over long periods as it may cause addiction and no longer works effectively for pain relief.

Sometimes you will be told to take Panadol or Panadeine or Panadeine Forte 4 hourly, when you go home, depending on how severe your pain is. It is important that you only take one type of these tablets every 4 hours. Do not take Panadol and Panadeine and Panadeine Forte at the same time. This will not improve your pain relief. This will give you too much paracetamol and may be bad for you.

Oxycodone. (Also known as Endone or Oxycontin. ) This is a strong pain relieving drug that is only available on prescription for short-term use. Usually it is only given to you in hospital. Sometimes you may be sent home with this medication. It is stronger than codeine and is even more likely to cause drowsiness, nausea and vomiting. It may cause constipation and is more addictive than codeine.

Tramadol. Tramadol is a prescription only drug, related to the opioid drugs discussed below. It is available both as an oral preparation and for injection. It may cause nausea, vomiting and sweating. It may cause drowsiness. Tramadol can cause fitting and is usually not prescribed for people who suffer from epilepsy. Prolonged use of Tramadol may also lead to addiction.

These drugs are useful, because in addition to providing pain relief, they also reduce swelling around the operation site. This group of drugs is not suitable for everyone and you should check with your doctor. They are not suitable for people with heartburn, stomach ulcers or other stomach problems; asthma; heart problems or kidney problems. Pregnant women should avoid this group of medicines.

Some people may already take one of these drugs regularly, if, for example, they have arthritis. It is important that you only take one of the medications in this group . If you take more than one the side effects add together and can be much more severe.

Ibuprofen. (Commonly known as Nurofen, Brufen, Advil or Herron Blue. Again there are a number of brands, which are the same drug). This is available over the counter at pharmacies or from supermarkets. This medication is taken 4 hourly and can be taken in addition to the paracetamol preparations.

There are a large number of anti-inflammatory drugs that are available only on prescription from your pharmacy. These include:

ASPIRIN

Warning . Aspirin (also known as Aspro or Aspro Clear ) interferes with blood clotting and so is not recommended for postoperative pain relief, as it may cause bleeding. If you are regularly taking aspirin ( Cardiprim or half an aspirin daily) on your doctor's advice, you should talk to your surgeon or anaesthetist about stopping the aspirin three weeks before surgery. If you do not take aspirin regularly, you should avoid it for three weeks before your operation.

Suppositories are waxy pellets that are placed in the back passage. They contain the same medications discussed under oral medications.

• It is not always possible to tolerate oral medications following surgery and anaesthesia. You may have nausea or you may not be permitted to take anything by mouth.

• They provide a sustained slow release of drug into the body, which can sometimes provide better pain relief.

In addition to the usual side effects produced by the medication used, suppositories may also cause diarrhoea with prolonged use.

INJECTED PAIN RELIEF

Pain relieving medications can also be given via injection into the body. They may be given into a vein (intravenous), into a muscle (intramuscular) or under the skin (subcutaneously). These are methods of pain relief that are used during your stay in hospital; they are not used at home for postoperative pain relief.

These drugs are given as injections to relieve pain. It takes half an hour after these drugs are injected into a muscle for these drugs to work. The pain-relieving effect of these injections lasts for 3 to 4 hours. The degree of pain relief achieved with injected opioids is variable.

There are disadvantages with intramuscular injections in particular as the injection can be painful; it is difficult to maintain a consistent blood concentration of the drug; and, there can be delays between the request and actual giving of the injection.

The main side effects of these injections are: nausea and vomiting; drowsiness; itching; constipation; and pain, swelling and bruising at the injection site. It is common to give other drugs that reduce nausea and vomiting with opioids, but these drugs may also have side effects. Allergic reactions are possible with any drug, but are uncommon with pethidine and morphine.

Rarely opioids can cause respiratory depression; this is a reduced ability to breathe. If respiratory depression occurs, it can be reversed using a drug called naloxone (Narcan). Unfortunately, naloxone also reverses the pain-relieving action of the opioids.

The prolonged use of opioids may lead to addiction, but this is not a problem with the short-term use for postoperative pain relief.

For patients staying overnight or longer, this is the most common method for providing pain relief within hospitals. An electronic pump is used to deliver morphine or pethidine via an intravenous drip. This is a method that allows you to administer your own pain relief.

You are given a controller with a button to press when you need another dose of pain relieving drugs. Each time the button is pressed, the electronic pump gives you a measured dose of pain relieving drugs via the intravenous drip. This may occur together with a continuous background infusion of pain relief.

This method is safe to use. Limits are set on the size of the dose you receive each time and the number of doses you can receive; there is a lockout mechanism that sets a minimum time between doses. Extra monitoring may be needed for patients who have sleep apnoea.

The side effects are the same as those listed above for pethidine and morphine. For patients who are unable or don't wish to use PCA, your anaesthetist may just run a continuous infusion. The amount of infusion or the size of the bolus doses can be altered according to your needs.

Although most patients find PCA successful in relieving their pain, not everyone does. If your pain relief is not adequate, tell the staff. The doses can be altered or a different type of pain relief used.

Tramadol. Tramadol is related to the opioid drugs and is also available in injectable form. It may cause nausea, vomiting and sweating. It still causes some drowsiness, but is less likely to cause respiratory depression than opioids. As discussed above, there is an increased chance of fitting with the use of Tramadol.

Injectable Anti-inflammatory Drugs

(Also known as NSAIDs or Non-Steroidal Anti-inflammatory Drugs)

The NSAIDs, given orally, rectally or by injection, are often combined with the opioid drugs for pain relief while in hospital. The side effects and risks are as for the oral form of the NSAIDs. There are two drugs in this class that are used for injection in Australia.

LOCAL ANAESTHETIC BLOCKS

Local anaesthetic blocks involve the injection of special drugs that make specific parts of the body go numb. This can range from making a single finger go numb to making half of your body numb. These blocks are particularly safe when small parts of the body are made numb. Larger blocks, such as epidural or spinal anaesthetic, can also be safer than a general anaesthetic. Your anaesthetist may use a local anaesthetic block with or without sedation, as the main method of anaesthesia for your operation, because local anaesthetic blocks provide better pain relief following surgery. They can also be used with general anaesthetic for postoperative pain relief.

Types of local anaesthetic blocks

Local anaesthetics may be injected directly at the site of surgery, or to block a single nerve or even whole groups of nerves to make parts of the body go numb and prevent pain.

Nerve plexus blocks. Nerves are grouped together in some parts of the body. Such a group of nerves is called a plexus. The whole upper limb and parts of the lower limb can be made numb by injecting a local anaesthetic drug near the groups of nerves that supply the limbs. For the upper limb, this is most commonly done by injecting the local anaesthetic into the armpit, but can also be done by injecting in the neck, or either above or below the collarbone. For the lower limb, this can be done in the upper thigh or behind the knee. It is common to give sedation when the block is put in. This technique is best used for longer, larger operations on the limbs and occasionally can be continued for postoperative pain relief in the ward.

Individual nerve blocks. Individual nerves in the face, mouth and limbs can be blocked by injecting the local anaesthetic near the individual nerve that supplies the area of the body where the procedure will take place. These blocks are particularly safe. Because smaller doses of local anaesthetic are required, there are less potential complications.

Epidural and Spinal Analgesia. Epidural or spinal analgesia is an injection of local anaesthetic, often with other pain-relieving drugs, into the back. Your anaesthetist uses this type of block to make a large region of your body go numb. Epidurals may be used as the anaesthetic for some operations, but they are also used in combination with a general anaesthetic or a spinal anaesthetic. Your anaesthetist may recommend this type of block, because it may provide better safety, quicker recovery and better postoperative pain relief than a general anaesthetic alone.

Running down the middle of the backbones (spine) there is a sac of fluid called the dural sac. A spinal anaesthetic is an injection of local anaesthetic through the back, into the fluid inside the dural sac. An epidural anaesthetic is an injection of local anaesthetic through the back, into the area outside of the dural sac. Nerves travel both inside and outside the dural sac and the local anaesthetic is used to block these nerves and make parts of the body go numb.

When postoperative epidural analgesia is used, a plastic tube, called an epidural catheter, can be threaded into the epidural space and left there for ongoing doses of local anaesthetic until pain relief is no longer required. When an epidural is used it is common for an electronic pump to be used to provide a continuous infusion of local anaesthetic via the epidural catheter. An epidural may be used for several days.

Another local anaesthetic block used for postoperative pain relief is a caudal anaesthetic. This is like an epidural anaesthetic, but given lower down in the back.

Although spinal anaesthetics are a single injection, usually given to provide anaesthesia for the operation, other drugs, such as Morphine, can be given in the spinal injection to provide pain relief lasting up to several days, without causing numbness.

Numbness and muscle weakness. The most noticeable side effect of epidural analgesia is numbness and weakness of the lower half of the body. How effective the pain relief is depends on how large a dose of epidural anaesthetic you receive. Larger doses of anaesthetic provide better pain relief, but are also associated with greater muscle weakness. This greater weakness means you will not be able to walk around. Spinal opioids for postoperative pain relief do not cause numbness or weakness.

Drop in blood pressure. Although usually not noticed by the patient, the use of an epidural or spinal anaesthetic causes blood pressure to drop. Low blood pressure is usually controlled by giving fluids via the intravenous drip. Uncommonly, medication may be required to correct the drop in blood pressure.

Shivering. Shivering due to an epidural can be quite marked, but is of no medical concern. It is usually managed by keeping the patient warm.

Difficulty passing urine. A spinal or epidural injection makes it difficult to sense a full bladder. It is usual to need a catheter to drain the urine. There is a small risk of bladder infection associated with using a urinary catheter; however, without a catheter, the bladder may not empty.

Nausea and vomiting. Nausea and vomiting can occur with spinal and epidural analgesia. There are medicines that can be given to reduce nausea and vomiting if necessary.

Itching. Morphine may cause itching of the chest, face or arms when given in an epidural or spinal injection. Should this occur, it can be treated with Naloxone (Narcan). The low dose of Naloxone used to treat itching does not stop the pain relieving effects of Morphine. This itching is not an allergic reaction and if you experience this specific type of itching, it does not mean that you are allergic to Morphine.

Risks and Complications associated with Local Anaesthetic Blocks

As with general anaesthetics, there are risks associated with local anaesthetic blocks.

Pain at injection site. Pain and bruising at injection sites are common but are expected to resolve within 2 weeks

Inadequate block. Local anaesthetic blocks are often temperamental. Epidurals can be patchy, may only block one side, may block too high or too low, or may miss blocking individual nerves and as epidural catheters are only held in by tape, they can leak or fall out. In some cases, local anaesthetic blocks can be inadequate. There are several ways of managing these problems. Changes in your position and additional doses of local anaesthetic.

There is a lot of individual variation in people's size and shape and requirements for local anaesthetic. It is not always possible for the anaesthetist to put in some blocks such as an epidural or spinal injection.

Death or serious complications. Although these risks are often lower with a local anaesthetic block than with general anaesthesia, they still exist and cannot be totally eliminated. Serious complications may include conditions such as: heart attack; stroke; brain damage; fitting; high spinal anaesthetic block; DVT (blood clot in the leg); pulmonary embolus (blood clot in the lungs); major allergic reaction; and, irregular or slow heart beat. However, for large operations, there is some evidence that epidural or spinal analgesia actually reduces the risk of some of these complications, especially lung infections and DVT. Even though many patients are worried about serious complications, the chance of dying or having a serious complication because of an anaesthetic is extremely low. For a young healthy person, the chance is so low that it is not possible to measure it accurately. For those with poor general health, especially heart or lung disease, the risks may be greater. You should discuss your individual risks with your anaesthetist.

Post spinal headache. A headache can occur after spinal or epidural injection in up to 1% of healthy young people and is far less common in older age groups. This headache can be mild or severe and usually resolves spontaneously over 1-3 weeks. It can be cured more quickly using an epidural injection of the patient's own blood. If you have a persistent headache following an epidural or spinal anaesthetic you should contact your anaesthetist. It is also important to understand that there are many other causes of headache that are more common. It is also possible to have temporary deafness following a spinal anaesthetic.

Infection. Infections related to local anaesthetic blocks, including epidurals or spinals are extremely rare, so rare that it is not possible to give an accurate incidence. All of the needles, catheters, local anaesthetics, intravenous drips, syringes, tubing and fluids are sterile and used for one patient only. Your anaesthetist uses a sterile technique to insert a local anaesthetic block. However, it is not possible to totally eliminate the risk of infection at the injection site. With epidurals and spinal anaesthetics it is possible to develop an infection around the spinal cord, causing meningitis or an abscess. This extremely rare type of infection may have serious consequences and result in brain damage, paraplegia or death. Infection may require antibiotic treatment, or very rarely surgery.

Nerve Damage. Nerve damage is uncommon and usually only temporary, but rarely may be permanent. The type and extent of damage depends on where the block is placed. Nerve damage may range from causing a very small area of numbness, pain or weakness to, in extremely rare cases, paraplegia or quadriplegia.

OTHER FORMS OF PAIN RELIEF

Less severe pain can be dealt with using relaxation techniques, breathing exercises, hot or cold packs, massage or TENS (Transcutaneous Electronic Nerve Simulation) machine (gentle electrical stimulation of the skin). Some people find other methods of pain relief such as: hypnosis; acupuncture; and aromatherapy helpful, but in general these methods are less useful in managing postoperative pain. They are probably most useful when used together with the methods discussed above, rather than on their own.

WHEN YOU GO HOME

• Don't drive a car, operate dangerous equipment or tools, make important decisions, sign legal documents or drink alcohol while taking pain relieving drugs.

• Arrange for a responsible adult to accompany you home by car or taxi (don't take public transport) and stay with you for 24 hours.

• Rest quietly at home and arrange for someone else to care for small children or other dependants.

• Local anaesthetics take time to wear off completely. If part of your body is still numb, you need to take care not to injure yourself.

• Make sure you have a clear understanding of which medications to take, especially for pain relief. You may need extra pain relief when a local anaesthetic block wears off.

• If you have any concerns call your anaesthetist, surgeon or the facility at which you were treated.

This information has been prepared by Dr G. Eastaugh MMBS, FANZCA and Dr L Eastaugh MBBS, MBA to give you a better understanding of your postoperative pain relief, but cannot replace professional advice regarding your individual circumstances. It is important that you are satisfied that you understand the information regarding your postoperative pain relief. If you are unsure or concerned about any of this information you should talk to your anaesthetist.

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