The objective of postoperative care after thoracotomy is to enable patients to resume the normal activities of daily living, to prevent postoperative complications, reduce the length of hospital stay and increase patient satisfaction. However, pain can hinder these objectives and may result in sputum retention, deep-vein thrombosis, increased stress response and poor wound healing. It may also lead to chronic pain.
In order to prevent chest infection after surgery, patients are encouraged to be actively involved in early mobilisation and chest physiotherapy. Unfortunately, deep breathing exercises and secretion clearance require the chest wall to be in constant and often forceful motion. Since it cannot be immobilised to aid the management of postoperative pain, this aspect of care can present significant challenges to health professionals (Richardson et al, 1999).
Pain assessment, which should include using a validated pain score tool, and obtaining a description of the pain and its site, as well as what makes it worse or better, is an important aspect of pain management. Pain scores should be documented, acted upon, re-evaluated and measured when the patient is at rest and, more importantly, during activity. During the pre-operative assessment, nurses should record any previous pain experience of the patient and/or current analgesia, as these factors may influence postoperative management. Any existing pain issues or anxieties should be highlighted and, reported to the acute pain service before surgery.
Access to the thoracic cavity can be achieved using a variety of surgical techniques, including those commonly used in cardiac surgery, for example sternotomy and left anterior thoracotomy (also known as the mini-thoracotomy).
Laparoscopy, known as video-assisted thorascopic surgery (VATS) is used for procedures such as pleurodesis (adhesion of the pleural layers) for treatment of pneumothorax, diagnostic lung biopsies, and lung volume reduction.
It has been suggested that this technique causes minimal disruption to the chest wall (Kruger and Sandler, 1999) and may lead to improved pain management, a shorter recovery period, less impairment of lung function and minimal scarring (McKenna and Houck, 2005) compared with surgery involving a standard thoracotomy incision.
Posterolateral thoracotomy for lung resection is performed to gain access to the thoracic cavity. It is associated with a high incidence of pain. The skin incision usually extends from the fifth intercostal space posteriorly to the eighth intercostal space anteriorly.
Transection of large muscle groups, the latissimus dorsi and the anterior serratous, is required for this procedure, and may contribute to postoperative pain. Kruger and Sandler (1999) suggested that a muscle-sparing technique involving retraction instead of transection of these large muscles during surgery may reduce the postoperative pain. However, they acknowledged that this may also hinder surgical access.
Retraction of the ribs and occasionally rib resection is necessary during posterolateral thoracotomy in order to maintain good access to the lung. Nerve injury can occur as a direct result of pressure from the rib retractors or from tissue displacement at both edges of the retractor, which stretches the intercostal nerve (Buvanendran et al, 2004). This nerve damage may lead to neuropathic and chronic post-thoracotomy pain.
Although its cause is disputed, shoulder pain is common following thoracotomy, occurring in 75 per cent of patients (Tan et al, 2002). Surgery involves placing patients in the lateral position, with the upper arm supported above the head to allow access to the surgical site. It has been suggested that the shoulder joint capsule and ligaments are strained from using this positioning. However, studies have shown that this is more likely to be due to referred pain transmitted via the phrenic nerve as a result of diaphragmatic irritation (Tan et al, 2002; Scawn et al, 2001).
Chest drains are inserted at the end of surgery to facilitate fluid drainage and lung re-expansion and are often responsible for pleural and diaphragmatic irritation postoperatively.
Types of pain
There are nociceptive and neuropathic elements to post-thoracotomy pain. Nociception relates to an individual’s ability to detect a painful stimulus. It is intended to be a protective mechanism, warning the body of harm and alerting it to the need to avoid further injury. Nociceptive pain is classified as somatic and visceral (Table 1).
Nociceptive pain normally responds well to conventional pain management therapies such as non-opioids, opioids, non-steroidal anti-inflammatory drugs (NSAIDs) and regional analgesia. However, NSAIDs should be used only in selected patients because of their potential effects on platelet function and complications of gastrointestinal bleeding (Soto and Fu, 2003). They should be used with caution in patients following thoracic surgery who may be dehydrated, because of the potential for renal impairment (Hughes and Gao, 2005).
Neuropathic pain arises from damage or injury to the nervous system, either centrally or peripherally. It is commonly described as a burning, shooting, numb or electric shock sensation in the dermatome of the affected nerve. After surgery or the insertion of chest drains, patients often complain of neuropathic pain around the wound incision site or along a dermatome where the affected nerve has been injured, for example, on the lower border of a rib.
Neuropathic pain responds poorly to analgesic drug therapy. Tricyclic antidepressants, anticonvulsants, transcutaneous electrical nerve stimulation (TENS) and regional analgesia have been used in its treatment rather than conventional methods alone (Wolfe et al, 2002). This type of pain is responsible for the increased incidence of chronic pain following thoracotomy.
Modes of analgesia
Systemic opioids, regional techniques and adjuvant therapies are all used to manage pain. Psychological methods such as distraction therapy, imagery and relaxation techniques may also be useful, particularly if the pain has increased as a result of anxiety. Non-pharmacological interventions may include simple measures such as supporting the patient in a comfortable position using pillows, encouraging regular changes of position or applying heat to prevent muscle stiffness, particularly in the shoulder of the operative side.
As with all painful conditions, a multimodal approach to pain management should be adopted under the guidance and expertise of a pain nurse specialist or anaesthetist.
Systemic opioids such as morphine and fentanyl are extremely effective in managing acute pain, and they remain the basis of postoperative analgesia. However, there is concern about their respiratory depressant side-effects.
A more efficient method of intravenous opioid delivery is patient-controlled analgesia (PCA). This has been shown to reduce the incidence of adverse side-effects such as nausea and vomiting, respiratory depression and reduced gut motility (Peeters-Asdourian and Gupta, 1999). However, PCA is not suitable for all patients (particularly those who do not understand how to use the handset or who are unable to control it because of disability), as its inappropriate use may lead to either increased side-effects or uncontrolled pain.
Epidural analgesia involves administering drugs directly into the epidural space (Cox, 2001). A combination of a local anaesthetic (bupivacaine or levobupivacaine) and a strong opioid (fentanyl or diamorphine) is often used for their combined synergistic effect, as this allows smaller doses of each agent to be administered, thereby reducing the incidence of side-effects. A continuous infusion of combined agents or local anaesthetic alone is usual practice for patients following thoracotomy, as there is a lack of evidence for using patient-controlled epidural analgesia in this group (Soto and Fu, 2003).
The insertion of epidural catheters may not be suitable for all patients and is contraindicated in those with coagulopathy disorders, neurological dysfunction, local or systemic sepsis (Peeters-Asdourian and Gupta, 1999), as well as those who do not consent to the procedure. It is a highly technical mode of analgesia requiring ongoing educational programmes to maintain nursing knowledge (Cox, 2001).
Thoracic epidural analgesia has generally been considered the analgesic route of choice for patients who have had a thoracotomy. Side-effects include hypotension, urinary retention, itching, nausea and vomiting. Rare complications include epidural abscess or haematoma, which could lead to paralysis if diagnosis is delayed.
Paravertebral block (PVB)
This involves injecting a local anaesthetic via a paravertebral catheter that is placed in close proximity to the spinal nerves, resulting in unilateral nerve block covering several dermatomal areas above and below the injection site (Karmakar, 2001). A continuous infusion of local anaesthetic can be used.
PVB is used in conjunction with PCA in the initial postoperative period and has been found to be opioid-sparing, with consequently fewer side-effects such as nausea and vomiting compared with PCA alone (Marret et al, 2005).
The incidence of urinary retention and hypotension is reduced in patients receiving PVB compared with those receiving epidural analgesia (Soto and Fu, 2003). PVB is a useful alternative for those who are not suitable for epidural analgesia or where insertion of an epidural has failed.
Intercostal nerve blocks
Pain in the wound incision or drain sites may be managed using single injections of a local anaesthetic into several intercostal spaces above and below the site of pain. Although these are effective and simple to perform, the pain relief they give can be short-acting, requiring multiple injections of large volumes of local anaesthetic, thus increasing the risk of local anaesthetic toxicity (Hughes and Gao, 2005).
Interpleural analgesia also provides intercostal nerve blockade and can be administered as a bolus or by continuous infusion of a local anaesthetic. It involves inserting an indwelling catheter into the interpleural space between the visceral and parietal pleura. Unfortunately it is thought that the local anaesthetic is lost to the chest drains, so limiting its efficacy (Soto and Fu, 2003), and that toxicity may also develop through absorption of local anaesthetic solution.
Pain after thoracic surgery is best managed using a multimodal or balanced analgesic approach in combination with non-pharmacological interventions. This involves using different classes of drugs, such as non-opioids, opioids, NSAIDs and regional techniques, depending on the type of surgery and individual tolerance.
A simple approach to pain management should be adopted whenever possible and use of the World Health Organization (WHO) analgesic ladder (WHO, 1996) may be beneficial as it provides a stepwise solution in accordance with the intensity of the pain, whether it is decreasing or increasing, and the effectiveness of the analgesic regimen.
Although originally developed for use in cancer pain, the analgesic ladder can be adapted for use in acute pain (McQuay, undated, see references), as it offers guidance on step-down analgesia following the use of strong opioids and epidural analgesia.
On discontinuing ‘high-tech’ modes of analgesia, the use of regular paracetamol with a weak opioid, such as codeine or tramadol, is recommended until the patient is able to step down to paracetamol alone.
Adjuvants, such as NSAIDs, TENS, regional blocks and neuropathic drugs can be administered at any step along the ladder.
The addition of analgesia on an as-required basis allows patients to control incidental or breakthrough pain pre-emptively before interventions such as chest drain removal and physiotherapy. Although the chest cannot be immobilised, patients can be encouraged to ‘hug’ their chest during coughing or physiotherapy to help support the wound and thereby reduce the level of incidental pain.
Pain is a subjective experience and its management should be individually tailored in the thoracic surgical patient using an holistic approach. Effective communication between the patient and members of the multidisciplinary team is also important.
Assessment should involve listening to the patient and involving him or her in management decisions. The mode of analgesia chosen will depend on the type of surgical incision, the type of anaesthetic the patient has received, the patient’s choice of regional analgesia and the suitability of the patient for the different classes of analgesic drugs. Effective communication between the patient and members of the multidisciplinary team will ensure pain is treated in a timely and effective manner.
As the patient’s advocate, the nurse plays a crucial role in postoperative pain management. A successful pain management plan involves implementing a balanced analgesic regimen that is patient-focused and that meets the changing needs of the individual throughout the immediate postoperative period and ongoing recovery.
- This article has been double-blind peer-reviewed.
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