A 70-year-old male is admitted to the ICU following esophagectomy for esophageal carcinoma via laparotomy and right thoracotomy. He has a history of former tobacco use (40 pack-years), hypertension, type 2 diabetes, non–obstructive coronary artery disease, and stage 3 chronic kidney disease.
A thoracic epidural was placed preoperatively and started during the surgery. Postoperatively, the epidural infusion consists of ropivacaine 0.1% with fentanyl 2 µg/mL at 6 mL/h. Initially, the patient complained of rightsided shoulder pain that was relieved with addition of scheduled acetaminophen. On postoperative day 1, the patient is comfortable at rest, but complains of a small area of distal abdominal incisional pain that is uncontrolled when he moves or coughs. He has minimal chest wall pain.
Which of the following is the most appropriate initial change to his pain regimen?A. Add scheduled intravenous morphine and ketorolac
Correct Answer: B
Pain following thoracic surgery can be a serious issue for patients, not only because of its intensity and duration but also because of its adverse effects on pulmonary function and recovery.
Opioids are considered a mainstay of significant postoperative pain management. However, a narrow therapeutic range and potential for sedation and respiratory depression are general limitations of this class of drugs. Morphine (A) in particular should be used with caution in elderly patients and patients with renal disease due to its active metabolites and long-lasting effects. Although addition of an intravenous opioid might improve this patient’s pain control, his major complaint has to do with pain with activity, and scheduling morphine is not the most appropriate first step.
NSAIDs are reversible COX inhibitors that can be very effective for treating the inflammatory component of postoperative pain. In general, meta-analyses of randomized controlled trials report improved pain scores and reduced analgesic use when intravenous morphine combined with ketorolac is compared with intravenous morphine alone. With respect to thoracotomy pain, the addition of NSAIDs as part of a multimodal pain regimen can be especially effective to treat shoulder pain that is refractory to epidural anesthesia, as well as to reduce overall opioid requirements. However, NSAIDs have also been associated with decreased platelet function, gastric erosions, increased bronchial reactivity, and decreased renal function. NSAIDs should be used with caution in patients who are elderly or have known risk factors for postoperative renal failure, including hypertension, diabetes, and preexisting renal disease. This patient’s shoulder pain has already been relieved by acetaminophen, which is a weak COX inhibitor. Although NSAIDs may also improve his incisional pain, scheduled ketorolac (A) would not be the best option given his age and comorbidities.
Currently, in the absence of contraindications, a thoracic epidural may be considered the “standard” of analgesia for open thoracotomy. Coverage of dermatomes far from the site of insertion can be achieved by increasing volume of local anesthetic or replacing epidural fentanyl with a hydrophilic opioid such as hydromorphone (B) or morphine, as highly lipid-soluble agents are associated with narrower dermatomal spread, and given his pain is concentrated to a small area, the fentanyl may be spreading too much.
Paravertebral catheters (C) have been shown to have similar efficacy to epidurals following thoracic surgery and are a reasonable alternative. However, this patient’s epidural appears to be functioning, given that he has no chest wall pain and only a small distal area of pain. Before proceeding with another invasive procedure, it is more appropriate to attempt to augment the existing epidural by changing the solution or increasing the rate.
Increasing the concentration of ropivacaine in the epidural while halving the rate (D) would potentially increase the density of the blockade, but not the spread.