It is essential that patients undergoing thoracotomy be informed about what to expect after surgery because an understanding of the procedure as well as realistic expectations of pain and rehabilitation can promote recovery and return to normal activity. Patients undergoing thoracotomy may suffer from severe acute postoperative pain if analgesia is not managed appropriately. Pulmonary function is impaired as a result of thoracic surgery and may be worsened by the effects of pain. Therefore, during the early postoperative period, pain control and maintenance of pulmonary function are the major goals. For preoperative improvement of pulmonary function, patients should be advised to stop smoking and be instructed in deep breathing exercises such as incentive spirometry.

Different techniques may be used to manage different levels of pain intraoperatively, immediately following surgery, within the first few postoperative days, and for discharge home. Pain management for these cases often involves a step-down approach from neuraxial
anesthesia and/or intravenous opioids to oral medication. The following issues should be addressed:

The decision about which anesthetic technique to use for an individual patient is based on a review of their overall medical condition and any medications that they are taking. General anesthesia combined with epidural anesthesia or analgesia may be selected based on the patient’s comorbidities and the planned procedure. Because lung volumes after thoracic surgery may be reduced by up to 50% through a combination of resection and splinting atelectasis, epidural analgesia can have benefit not only for pain relief but also for improving pulmonary function. Other factors such as surgeon preference, anesthesiologist experience and practice, and institutional protocols for postoperative pain relief may also influence the choice of anesthetic technique. If placement of an epidural catheter is included in the anesthetic plan, it may remain inactive throughout the case, used as an adjunct to general anesthesia, or bolused at the end of the case prior to a postoperative infusion. Again, this decision is often based on patient and surgical considerations, such as potential blood loss, hypotension, need for fluid restriction, and invasiveness of surgery. Intraoperative epidural use prior to wake up has the benefit of ensuring epidural catheter function and can facilitate a more comfortable transition to the immediate postoperative period.

The use of TEA has become widely used for management of pain associated with thoracic and major abdominal surgery. Clinical studies have shown that TEA can have effects far beyond pain relief, including decreased opioid consumption, reduced risk of nausea and vomiting, increased lung volumes, reduced risk of pulmonary complications, improved bowel recovery, and a significant reduction in the incidence of myocardial infarction. There is also evidence that neuraxial block decreases the risk of recurrence after certain cancer resections, likely through an opioid-sparing effect.

Chronic PTPS is defined as pain that recurs or persists along a thoracotomy scar at least 2 months after surgery and is not related to the recurrence of a tumor or an infection. PTPS is generally neuropathic in nature and varies in severity, with a reported incidence of 44% to 80%. Several studies suggest that severe perioperative pain is a predictor for development of chronic postoperative pain and thus aggressive management of early postoperative pain may be important to prevent this transition.

Although used with increasing frequency, thoracoscopic approaches have not had the favorable impact on pain that many had anticipated. Surprisingly, video-assisted thoracic
surgery is associated with a prevalence of chronic pain comparable to that of open procedures, with rates of PTPS ranging from 22% to 63%, likely due to intercostal nerve and muscle damage from trocar insertion and chest tube placement.

The analgesic plan should consider the entire perioperative period. A multimodal approach would be preferable to account for the multiple pathways by which nociceptive input is conveyed to the central nervous system, the number of pharmacologically distinct mechanisms of modulating this input, the need for effective analgesia throughout the perioperative period and after discharge, and the importance of minimizing side effects, particularly respiratory depression.

TEA is the mainstay of recommended therapy for the reasons previously discussed. Contraindications to a thoracic epidural include patient refusal, coagulopathy, thrombocytopenia, therapeutic anticoagulation, previous thoracic spine surgery, and local infection over the entry site. When epidural catheters fail intraoperatively or have patchy coverage, intercostal nerve blocks (ICNBs) or paravertebral blocks may supplement epidural analgesia or serve as a bridge to the immediate postoperative period when an epidural catheter can be safely replaced.

NSAIDs are useful for treating shoulder pain secondary to referred diaphragmatic pain. This nociceptive input is carried by vagal and phrenic nerves and is often refractory to epidural analgesia. A concern with NSAIDs is platelet dysfunction; however, their efficacy and lack of respiratory side effects makes them an optimal choice for adjunct analgesia when possible. Cyclooxygenase 2 (COX-2) inhibitors have more limited effects on platelets aggregation and comparable efficacy to traditional NSAIDs and thus may be of use in this setting. Adverse cardiac side effects are unlikely with short-term perioperative dosing. Regular administration of paracetamol or acetaminophen (APAP) may also be useful for treating shoulder pain and can be used in addition to NSAIDs. Topical lidocaine patch or use of gabapentinoids may also have a role is select patients.

Evidence from multiple studies strongly suggests that epidural analgesia is associated with lower rates of perioperative morbidity and, in particular, fewer pulmonary and cardiac complications. More recently, a meta-analysis of patients receiving TEA versus PCA after surgery requiring general anesthesia demonstrated decreased mortality in the thoracic epidural group. Compared with systemic opioids, epidural opioids decrease the incidence of postoperative atelectasis, hypoxemia, and pulmonary complications overall. Effective pain control with an epidural technique leads to improved pulmonary function, more effective coughing, earlier mobilization, and improved cooperation with respiratory physiotherapy.

Postoperative myocardial infarction rates are reduced when TEA is incorporated into anesthesia and extended at least 24 hours into the postoperative period. Supraventricular tachyarrhythmias, which are the most common form of cardiac morbidity after pulmonary resection and occur in up to 50% of cases, are reduced by TEA, even when compared with alternative analgesic regimens that confer equivalent pain control. The cardioprotective mechanism of TEA is believed to relate to its sympatholytic effects.

Epidural analgesia also provides superior postoperative analgesia compared with IV-PCA. As discussed earlier, better postoperative pain relief may decrease the likelihood of developing chronic postsurgical pain, although it should be noted that this has not yet been demonstrated in longitudinal studies.

TEA is currently the standard for analgesia for thoracic surgery, and in the absence of contraindications, all patients undergoing major open thoracic surgical procedures should have a thoracic epidural catheter placed preoperatively. The tip of the catheter should ideally reside at the dermatome along which the incision will be made.

Thoracic (versus lumbar) placement of the epidural catheter is dose saving and decreases side effects such as hypotension and bladder dysfunction at equianalgesic doses. Thoracic placement also reduces motor block of the lower extremities, which allows for improved postoperative ambulation. However, if thoracic epidural placement is contraindicated or cannot be achieved, lumbar epidural anesthesia can be utilized. Lumbar placement can be efficacious, particularly when used with hydrophilic opioids such as morphine; however, local anesthetic volume dosing is significantly higher and may be limited by toxicity.

Effective postoperative pain control may be achieved by delivering an opioid, local anesthetic, or a combination of both into the thoracic epidural space. Combinations are the standard because synergy between opioids and local anesthetic agents can enable an optimum balance between analgesia and minimizing blockade of motor function of the thorax and dynamic consequences of sympatholysis. Common components include opioids, such as morphine, fentanyl, or hydromorphone, and local anesthetic agents, such as bupivacaine, levobupivacaine, or ropivacaine. Systemic absorption effects (e.g., sedation) tend to be more common with the lipophilic opioids, such as fentanyl, presumably because of increased absorption into the epidural fat. Hydrophilic opioids, such as morphine, produce a wider dermatomal band of analgesia with less systemic absorption. Of the three commonly used local anesthetic agents, bupivacaine possesses the least favorable cardiac safety profile. In theory, ropivacaine offers the advantage of differential dose-dependent sensory and motor blockade; however, when used in dilute concentrations in combination with opioids, it is unlikely that any advantage of one agent over the other will be apparent. Addition of low-dose ketamine to epidural infusion has not demonstrated beneficial effects in preventing postthoracotomy pain.

Before the initiation of PCEA, a test dose of 3 mL of 1.5% lidocaine with epinephrine 1:200,000 is usually employed to rule out intrathecal or intravascular placement of catheter.
Once malposition is ruled out, the catheter is usually bolused (as allowed by hemodynamic status) prior to beginning continuous infusion.

Commonly employed combinations of epidural drugs vary. However, in the interest of patient safety, compliance, auditing, and quality assurance, standardization within the institution is recommended. Solutions and volumes can later be titrated to effect or to avoid side effects, for example, increasing or decreasing local anesthetic concentration to change block density, increasing or decreasing volume infused to increase spread, and adding or subtracting opioids to increase analgesia or decrease side effects such as itching, nausea, or sedation.

The following drugs and drug combinations are often used at a starting infusion rate of 4 to 6 mL per hour with each demand bolus of 2 to 3 mL as needed.

(See sample order form, Fig. 51.1.)

If accidental dural puncture occurs during placement of epidural needle, the general practice is to remove the needle and place the epidural catheter at adjacent intervertebral spaces. The likelihood of intrathecal spread should be carefully assessed with the test dose. Epidural infusion may be started at the usual rate. Frequent monitoring for sensory and sympathetic block should continue in a controlled setting until the efficacy and safety of the epidural analgesia is established. In addition, the patient should be assessed for any symptoms of neuropathy relevant to the level attempted. The patient should be informed of the dural puncture and the potential for postdural puncture headache, although this is less frequent than with lumbar dural puncture.

There are times when for technical, medical, or other reasons thoracic epidural catheter placement is unsuccessful, undesirable, or not possible. Alternatives to mid-TEA include lower thoracic and lumbar epidural catheter placement, ICNBs, paravertebral blocks, intrathecal opioids, intrapleural catheters, local anesthetic infiltration, and systemic analgesia with one or more agents.

Lumbar epidural placement can be efficacious, particularly when used with hydrophilic opioids such as morphine to increase dermatomal spread. Lumbar epidurals are most limited by the need for increased local anesthetic dosing and the higher incidence of side effects such as hypotension and urinary retention versus thoracic epidurals.

If epidural placement is ruled out altogether for the reasons previously discussed, ICNBs can be performed percutaneously using anatomic or ultrasound-guided techniques or under direct vision intraoperatively, using single injections or placement of an intercostal catheter. While often initially effective, unpredictable spread of local anesthetic and rapid local anesthetic absorption by surrounding vessels make this technique less effective than epidural analgesia. Furthermore, indwelling intercostal catheters cannot adequately control pain after posterolateral thoracotomy because posterior primary rami and sympathetic fibers are not blocked. Additionally, percutaneous positioning and securing of intercostal catheters may be technically problematic.

Paravertebral block results in ipsilateral somatic and sympathetic nerve blockade in multiple contiguous thoracic dermatomes above and below the site injection. Paravertebral analgesia has been found to produce good pain relief and preservation of pulmonary function after

thoracotomy and is probably the best available alternative to epidural analgesia. Because the concomitant sympathetic blockade is unilateral, the incidence of adverse effects, such as hypotension and urinary retention, is lower. Paravertebral blocks can be performed as single injections or through a paravertebral catheter. Paravertebral catheters can be placed percutaneously via anatomic or ultrasound-guided approaches or intraoperatively under direct vision and may be more suitable than epidural catheters when coagulopathy is of concern. In some studies, paravertebral blocks have been shown to be as effective as TEA with respect to pain control and preservation of pulmonary function after thoracotomy.

A preoperative single bolus of spinal morphine as part of multianalgesic regimen can be considered in order to decrease the need for systemic opioids. Alternatively, pleural catheters may be placed intraoperatively to decrease pleural and visceral pain; however, they do not affect incisional pain and require high volumes of local anesthetic to be effective. Similarly, direct local anesthetic infiltration can be used but must be combined with longer acting strategies to provide adequate pain control throughout the perioperative period. Although systemic opioids have been well documented to reduce postthoracotomy pain, their adverse effects on the respiratory system after general anesthesia, even using patient-controlled delivery systems, and their inability to provide optimal dynamic pain relief favor regional anesthetic techniques, when possible, in thoracotomy patients. Systemic analgesics are best suited as adjuncts to these techniques and should become the mainstay of analgesic therapy only when invasive approaches are discontinued.

Clinical regimens for IV-PCA vary among institutions, but the most commonly used opioids are fentanyl, morphine, and hydromorphone. Continuous delivery, or basal rate, of the drug is commonly avoided to decrease the likelihood of respiratory depression. For opioid-naive patients, boluses of fentanyl 10 to 15 µg, morphine sulfate 1 to 2 mg, or Dilaudid 0.2 to 0.3 mg are given per demand with a lockout period of 8 to 10 minutes. Incremental boluses may be given by the nurse if pain is not controlled. The dose may be decreased or the opioid may be discontinued if respiratory depression occurs. Close monitoring and rescue strategies must be in place to ensure patient safety, particularly for at-risk individuals, including central monitoring of oxygenation and ventilation (see sample order form, Fig. 51.2).