A frail 92-year-old woman falls in the dining hall of her assisted living facility, sustaining an intertrochanteric fracture of the right hip. On hospital admission, routine lab tests, including complete blood count, electrolytes, blood urea nitrogen and creatinine, are normal. She undergoes hip replacement surgery under spinal anesthesia without complications and is alert and oriented postoperatively.
A patient-controlled analgesia morphine pump is initiated for pain control, set at the recommended dose for an opioid-naïve patient (2 milligrams every 10 minutes with a four-hour lockout rate of 24 milligrams). The patient is too drowsy to take her oral medications the next morning. What's the likely cause of the woman's sedation?
This case illustrates some of the complexities often present in pain management for orthopedic patients. The patient had low muscle mass, so her serum creatinine concentration remained within the normal range despite a significant reduction in her glomerular filtration rate. Reduced kidney function can lead to accumulation of opioid metabolites, which can result in associated side effects, such as respiratory depression and sedation. For appropriate pain management, this patient needed a lower dosage of morphine.
Two types of patients
Patients who need pain management after orthopedic surgery usually fall into two very distinct groups. Those admitted for surgical repair of a fracture are often elderly and have several comorbid conditions—such as diabetes, hypertension or chronic renal insufficiency—that may complicate their care. They're usually admitted under more urgent circumstances and may not have had the benefit of preoperative education or a comprehensive medical evaluation. Patients admitted for elective joint replacement, in contrast, tend to be younger, sometimes with fewer comorbid conditions, and usually have been evaluated and educated preoperatively.
Hospitalists should always be on the lookout for patients whose opioid requirement is higher or lower than the standard recommended dose, according to experts. Elderly patients with low body mass who have never taken opioids may require a much lower dose than younger, heavier patients who have used opioids in the past. In contrast, patients with a history of long-term opioid use before surgery are at risk for opioid withdrawal or insufficient pain management postoperatively.
Because pain management in orthopedic patients often involves intricate decisions, hospitalists are ideally situated to improve clinical care in this group, experts said.
“The hospitalists' role is critical when the ‘art’ of applying evidence-based pain management is required,” said Vijay Rajput, FACP, a hospitalist and associate professor of medicine at UMDNJ-Robert Wood Johnson Medical School in Camden, N.J. “For elective surgery, hospitalists play an important role in identifying preoperatively the patients at greater risk for complications with analgesics.”
Hospitalists should be aware of the following when managing pain in postoperative patients, experts said.
- Opioids' more common side effects include nausea and vomiting, constipation, ileus, confusion, delirium, and urinary retention in patients with benign prostatic hyperplasia.
- Careful monitoring is needed in patients at risk for opioid-associated respiratory depression due to obesity or sleep apnea, or to the extended half-life of active metabolites in the setting of renal dysfunction.
- Patients who develop delirium postoperatively should be evaluated for alcohol withdrawal.
- In patients with mild dementia, uncontrolled pain can present as agitation, confusion or psychosis.
Over the past five years, an array of new agents and new delivery methods has become available. Extended-release opioids using liposomal technology are now being used to deliver 48-hour pain relief via epidural injection without the need for an indwelling catheter. Other delivery options, such as a needle-free credit-card-sized iontophoretic transdermal system, are currently being studied.
A relatively recent trend in the management of postoperative pain is the focus on the use of a combination of analgesic agents rather than reliance on opioids alone. “Over the past five years, we've developed a greater understanding of the need for multimodal therapy,” said Craig J. Della Valle, MD, associate professor of orthopaedic surgery at Rush University Medical Center in Chicago. A primary goal of multimodal pain management, he said, is the use of a variety of drug classes to reduce the opioid requirement, thus minimizing the risk of opioid-associated side effects. An example of multimodal therapy is the combined use of spinal or epidural anesthesia, a peripheral nerve block, local injection at the operative site, a COX-2 inhibitor, pregabalin and other agents.
Many pain management strategies also include preventive or “preemptive” analgesia, which is the administration of analgesic agents prior to and during surgery to prevent postoperative pain. Agents such as COX-2 inhibitors, ketamine, pregabalin and acetaminophen are currently used for preemptive analgesia.
Preoperative patient education also is an important tool for pain management, according to Kulsum K. Casey, ACP Member, a hospitalist in the division of hospital medicine at the Mayo Clinic in Rochester, Minn. “Research has shown that educating patients about what to expect after their particular surgical procedure can reduce anxiety and their impression of pain postoperatively,” he said.
One of the most important reasons hospitalists are able to facilitate appropriate pain management is the amount of face time they spend with the patient, said Javad Parvizi, MD, associate professor of orthopedic surgery and director of clinical research at the Rothman Institute at Thomas Jefferson University Hospital in Philadelphia.
“Hospitalists often see the patient more frequently than the anesthesiologist or surgeon,” he said. “By helping foster communication among members of the team and with the patient, it's possible to achieve satisfactory analgesic control.”