Pain is a complex interaction of both mind and body, and the outcome of postoperative pain management is subject to many contributing factors. For example, staff and patient attitudes, particularly in relation to fears of addiction from the use of opioids, may prevent a patient from receiving adequate analgesics. Education of all staff involved in the management of patients postoperatively is essential, to ensure that unhelpful attitudes are challenged.

It is important to undertake a full assessment of the patient’s pain history. This should include questions about any previous surgery, previous and current analgesic use, and any fears or misunderstandings about analgesics, such as addiction or side-effects. Patients who have an existing opioid requirement or a substance abuse disorder will have a higher opioid requirement if they have surgery. Other factors such as the age of the patient will affect analgesia requirements. The elderly patient may have other ongoing pain problems due to conditions such as arthritis. They may take lots of different medicines in addition to analgesics (polypharmacy) and they may be stoic about pain, perhaps feeling that it is simply to be expected as part of an ageing life.

A patient’s personality can strongly influence the way in which pain is expressed. A patient who appears quiet and comfortable may not necessarily be so. It has been suggested that people with extroverted personality types are more likely to complain and to express their pain than introverted personality types. If this is so, then it could be argued that extroverts will probably receive more analgesics (Bond, 1984). A person’s culture can also strongly influence perception of pain and how pain is expressed, which will affect the outcome of treatment. In addition, the nurse’s own culture can influence how they assess pain and it is important for nurses to recognize how a cultural bias on their part can affect this (Davitz and Davitz, 1985).

Past experience may be reflected in the response of an individual to pain. Many of these responses are learnt during childhood and carried through into adult life, with associated personal beliefs and coping mechanisms.

It has been suggested that comparable stimuli in different people do not necessarily produce the same pain, either in duration or intensity (Melzack and Wall, 1991). This highlights the misconception that a particular operation or injury will produce a predictable level of pain. Interestingly, most people have a fairly uniform pain sensation threshold, which is the lowest intensity at which pain is felt, but pain perception and tolerance are not static. Pain perception and tolerance can be influenced by feelings of exhaustion, boredom, anxiety and isolation.

Wall (1999) anecdotally describes several reports illustrating how the meaning of the pain can influence the experience of the individual. It is also important to consider what the pain means to the patient and how this links in with the meaning of the surgery. For example, a patient undergoing a joint replacement will know that this is likely to improve their quality of life, whereas a patient who has had surgery related to cancer will have many anxieties due to the potential impact of their disease.

Pain assessment is the core of effective pain management. The patient must be involved in pain assessment where possible (Royal College of Surgeons of England, 1990), as it is the patient who knows how their pain feels (Moore et al, 2003). A study by Seers (1987) found that nurses frequently recorded the patient’s pain to be less severe than the patient’s own assessment, and it is probable that this still occurs.

Pain assessment in the acute or postoperative setting tends to focus on pain intensity. Although this may appear to be an overly simplistic measure, it provides a tool to help get treatment as quickly as possible. One of the most common measures in the acute pain setting is the categorical scale (Fig. 8.1) (Moore et al, 2003). This uses words such as ‘no pain’, ‘mild pain’, ‘moderate pain’ and ‘severe pain’ to describe the magnitude of pain. Numbers can be added alongside this verbal description to help the patient to use the tool and also to assist with analysis of data for audit purposes.

Pain assessment using the categorical scale may be difficult for some patients, such as the elderly or cognitively impaired. Pain assessment in the elderly must also consider other coexisting pain problems, which must be distinguished from the acute postoperative pain (Moddeman, 2002). Elderly patients may also be cognitively impaired, which can make pain assessment difficult. The use of standard pain tools should not be automatically excluded for these patients because additional simple, specific questioning can still be helpful (Victor, 2001). Victor (2001) also recommended the use of other measurements such as facial expression, sweating, increased heart rate, agitation and guarding. The Abbey Scale is a tool that uses six behavioural indicators to help measure pain in patients with dementia (Abbey et al, 2004).

Despite variation among patients in their ability to use some tools, it is often necessary to standardize pain assessment tools, to avoid uncertainty when staff move between areas in one hospital. Patients undergoing elective surgery should be introduced to a pain assessment tool preoperatively and written information given about how to use the tool and what to do if their pain is not controlled. The preoperative assessment clinic may be an ideal environment for the dissemination of this preoperative information, although it must be recognized that patients are given a great deal of information at that time and this may need revisiting on admission.

Severe acute pain can be physiologically harmful due to the stimulation of the sympathetic nervous system. The role of the sympathetic nervous system is to protect the body in times of stress, and stimulation causes several physiological responses known as the ‘surgical stress response’. These include the release of hormones such as cortisol and growth hormone; increased levels of blood glucose; and fluid and electrolyte imbalances. Increased metabolism will lead to an increased catabolism, requiring higher levels of oxygen. It has been suggested that the provision of adequate pain relief, utilizing epidural analgesia containing a local anaesthetic, may reduce this automatic response (Kehlet and Holte, 2001).

Poorly managed acute pain may be particularly harmful to the elderly or those with pre-existing cardiac morbidity, because of the resulting increased workload on the heart. More oxygen will be required if the heart is forced to work harder and this could be compounded further if the patient is unable to breath properly due to pain, resulting in lower oxygen availability. The elderly patient will also have an altered response to analgesics due to physiological changes such as a lower circulating blood volume and reduced muscle mass (Cooper, 2002). Reduced hepatic metabolism and renal function will mean that the elderly patient is likely to require smaller doses of opioids (Neal, 2001). In addition, frequent polypharmacy in the elderly patient may make them more susceptible to adverse drug reactions.

Oral administration of analgesics is the most acceptable route for patients, and it should be the first choice if possible. However, this route is seldom appropriate in the immediate postoperative phase, as gut motility is often reduced or the type of surgery may make this route impossible. If the oral route is used inappropriately, then there can be delayed absorption at an unpredictable time and if the patient is nauseated or is vomiting, there will be very little absorption of the drug.

Analgesics such as paracetamol and non-steroidal anti-inflammatory drugs (NSAIDs) can be administered rectally, although this method may not be acceptable to patients and it is therefore essential that verbal consent is obtained and recorded prior to administering drugs rectally. Absorption may be unpredictable and some NSAID suppositories can directly irritate the rectal tissues. The wide availability of intravenous forms of paracetamol and NSAIDs should reduce the need to use the rectal route in the postoperative setting.

The intravenous route is a rapid way of administering analgesics, including opioids, paracetamol and some NSAIDs. The administration of opioids by this route is often limited to clinical areas where there are high staff:patient ratios. The intravenous route is fast acting and easy to titrate to pain levels, but it requires the nurse to stay with the patient during administration and for some time afterwards. This close level of supervision may not be possible in a busy general ward; hence, this method is frequently reserved for use in more specialist areas or by an Acute Pain Service in general wards. Goodman and Gilman (1996) suggested that respiratory depression following the administration of intravenous opioids was most likely to occur within 7–10 minutes of administration; hence, it could be argued that the nurse would need to stay with the patient for at least 10 minutes following the last bolus injection. Best practice would also suggest that naloxone should be immediately available during administration, and that the nurse administering the opioid would remain responsible for the safekeeping of any unused portion of the drug until no more was required and any remainder could be discarded.

The use of a continuous intravenous opioid infusion is another method of administering opioids. However, this may lead to accumulation of the analgesic, so patients should be nursed in an area where they can be closely observed for the whole time that they are receiving opioids by this route (Dodds and Hutton, 2002).

The intramuscular route can be used for the intermittent ‘as required’ dosing of opioids and remains the traditional method of administering analgesics postoperatively. However, this method is rarely used, due to the wider use of more effective methods of analgesia. The intramuscular route commonly fails for several reasons. Most patients do not like injections, because they are painful. The nurse has control of the analgesia instead of the patient, and many patients worry about bothering the nurses if they are in pain, especially if the nurses look busy. Additionally, the prescribing and administration of intramuscular opioids may be inadequate and the pharmacokinetics are unpredictable, which may lead to intermittent analgesia and sedation, identified by Lovett et al (1994) as a bolus comfort sedation cycle.

However, the intramuscular route of administering opioids may be the most appropriate route of administration for a particular clinical setting, perhaps if that area has no staff trained in the management of epidurals or intravenous patient-controlled analgesia. It would seem reasonable therefore to make some effort to make this a more reliable and effective method of analgesia. One recommendation of the Joint Report of the Royal Colleges of Surgeons and Anaesthetists ‘Pain after Surgery’ (1990) was to utilize existing methods of analgesia more effectively and challenge traditional beliefs and attitudes. Harmer and Davies (1998) demonstrated that the introduction of a management algorithm allowing the hourly administration of opioids via an indwelling intramuscular cannula could improve patient experience whilst enabling staff to work within a much more flexible but safe system. Hourly administration of intramuscular opioids was also recommended by Dodds and Hutton (2002), who felt that this would be advantageous not only because patients would be less likely to experience peaks and troughs of analgesia but also because the dose could be more easily titrated and patients would have their pain assessed more frequently along with other vital signs. However, it was also recognized that such a change in practice may increase the workload for nursing staff if two nurses were required to check the analgesics. The subcutaneous route can also be used for the intermittent administration of opioids. This route requires no alterations to dosage or frequency of dosing as the absorption of the drug is similar to when given intramuscularly (Macintyre and Ready, 1997) and an indwelling cannula can also be used, as described above.

PCA is a common method of administering postoperative analgesia and many patients have benefited from using it. PCA empowers the patient to self-administer analgesics quickly within set parameters. Patients may also prefer PCA to other methods of analgesia as they may feel that they are less bother to the nurses (Seymour 1996). The aim of PCA is to keep plasma levels of opioid at a consistent, effective level without causing peaks and troughs of analgesia.

PCA is frequently used for both adults and children postoperatively. The most obvious criteria for its use are that the patient is physically able to use the chosen device and that they have the ability to understand the concept. Some patients may not feel that PCA is appropriate for them, as they may not wish to take control of this part of their care or they may associate the use of an opioid with drug addiction.

To help ensure best practice in the use of PCA, every step must be taken to reduce risk, such as the standardization of equipment and the use of prescribing guidelines or protocols. Any changes made within these to allow for individual patient need must be made absolutely clear by the prescriber and observation parameters may need to be altered as well. Administration lines used must be designed for PCA use, incorporating a one-way valve port for the safe attachment of intravenous infusions plus an anti-siphon valve to prevent gravity-induced siphoning which could occur if the PCA pump is placed too high. All staff using PCA equipment must be trained in its use, and this training must be provided as an ongoing programme.

It is important that all staff caring for patients using PCA can confidently manage the equipment. This must include being able to check the pump settings against the prescription chart, and monitor and confirm the amount of drug administered and the number of bolus demands, including unsuccessful demands. This information should be recorded with each set of observations, and each time a different nurse takes over the care of the patient. Staff must also be able to troubleshoot potential problems with the equipment and replace PCA syringes or infusion bags as needed, to ensure that the patient does not have a break in analgesia.