These cases are representative of procedures that are relatively common in elderly patients, and illustrate concepts of contemporary acute pain medicine.
Case 1: a 74-year-old Woman is Scheduled for Total Knee arthroplasty
Pain management treatment goals include pain control that still allows physical therapy to begin on postoperative day 1, avoids bladder catheterization, minimizes nausea and other opioid side effects and facilitates early hospital discharge.
Pain management pathways are usually separated into preoperative, intraoperative and postoperative phases. The preoperative phase involves patient education and administration of medications that prevent pain sensitization after surgery. Intraoperative measures aim to limit transmission of painful impulses to the CNS. Postsurgical efforts delay the onset of surgical pain and permit early physical therapy. Many of these efforts aim to significantly lower the need for opioids and diminish opioid-related side effects. The phrase 'multimodal analgesia' is often applied to the use of multiple complementary analgesics that enable pain management with minimal opioids and opioid-related side effects.
Preoperative phase (1–2 h prior to surgery)
Gabapentin 900 mg per orem (p.o.). Gabapentin provides protracted pain relief following a wide range of surgeries, and decreases the incidence of chronic surgical site pain.[119,120] It lowers postsurgical opioid needs by approximately 35% and diminishes opioid-related side effects. A single preoperative dose of gabapentin may increase the incidence of postsurgical sedation in the elderly for up to 24 h after surgery;
Dexamethasone 5 mg intravenous. Dexamethasone decreases wound inflammation and postsurgical pain for several days and is a potent antiemetic. It does increase serum glucose levels by approximately 20 mg/dl for 8–16 h. Unlike chronic steroid use, brief perioperative steroid exposure does not seem to alter infection rates;
Acetaminophen 1000 mg p.o. Acetaminophen lowers postsurgical opioid needs and has almost no side effects;[64–66]
Celecoxib 200 mg p.o. Celecoxib is a COX-2-specific NSAID, with no inhibition of platelet function and decreased gastrointestinal bleeding rates compared with nonselective NSAIDs. It shares with other NSAIDs the potential for decreased renal blood flow, fluid retention and exacerbation of hypertension and heart failure. The dose should be lowered in the elderly compared with younger patients, and should be avoided in patients with renal insufficiency, heart failure or sulfur allergy.[78,79]
We prefer to use spinal anesthesia for this procedure for several reasons. Compared with general anesthesia, spinal anesthesia is associated with less intraoperative blood loss and lower rates of postsurgical deep venous thrombosis. It also provides several hours of postsurgical pain relief;
Periarticular wound infiltration. The injection of high volumes of local anesthetics around the surgical joint provides sustained anti-inflammatory effects. The local anesthetics are usually combined with several other medications, such as ketamine and a steroid;
Low-dose intravenous ketamine (10–15 mg). Ketamine blocks the NMDA receptors at the spinal cord, which is the primary pain-relay site coordinating peripheral pain impulses connecting to the CNS. This low dose of ketamine does not cause psychological effects, and provides improved pain control for several months after surgery;
Ondansetron. This serotonin receptor-based antiemetic controls nausea and vomiting with fewer side effects than other antiemetics. In particular, phenothiazine-related antiemetics, such as droperidol and compazine often cause prolonged drowsiness and dysphoria, as well as occasional involuntary movements (extrapyramidal effects).
Femoral nerve block. The femoral nerve supplies the majority of pain sensation to the knee, and injection of local anesthetic surrounding the nerve dramatically reduces pain for 12–24 h. This permits early physical therapy, and minimizes the need for opioids. The benefits of femoral nerve blockade can be seen for up to 6 weeks following surgery in the form of an improved range of motion. One caution is in the first 24 h after femoral nerve block, when weakness of the quadriceps muscle may make falls more likely. Patients need assistance with walking and transfers to chairs during this time;
Scheduled (not 'as needed') acetaminophen. We usually use 1000 mg p.o. every 8 h. Patients with a history of significant liver disease or heavy alcohol consumption should not receive high doses of acetaminophen;
Celecoxib 100 mg p.o. every 12 h for 2 days. Please note cautions cited previously;
Opioids as needed. The goal of all of the alternative analgesics is to minimize the need for high dose of opioids with their attendant side effects;
Bowel regimen. Opioids cause constipation, and early use of stool softeners and promotility agents is often needed. Bulking supplements, such as psyllium, are not effective with opioid-related constipation.
Case 2: A 72-year-old Opioid-tolerant Male is Scheduled for Major Spine Surgery
When patients that chronically consume opioids require surgery or experience an injury, perioperative pain management is exceedingly challenging. Chronic opioid use is quite common in our patient population and, as a result, we see many opioid-tolerant older patients. Opioids are typically an integral part of perioperative pain management, but are markedly less effective in opioid-tolerant patients. Management centers on preprocedure education and maximizing the use of nonopioid analgesics. Preprocedure education involves setting realistic expectations for pain control, specifically informing the patient that pain control will be difficult, and that significant pain is highly likely. Finally, it is essential that an accurate history of daily opioid use is obtained, because what is consumed is frequently quite different from what is prescribed. The total daily opioid consumption usually increases 200–400% in the acute postoperative period (3–10 days), and is weaned back to the patient's baseline over several weeks.
If the patient is having a highly complex spine surgery, such as combined anterior and posterior spine fusion, postsurgical oral feedings may be delayed by mechanical ventilation and intestinal ileus. In this case, outpatient oral opioid dose must be converted to a parenteral opioid. There are multiple published tables that list opioid equivalents, but many clinicians use free web-based opioid calculators, such as the Kimmel Cancer Center at Johns Hopkins University's. This converter will take any combination of oral and transdermal opioids and convert them into an equivalent dose of a parenteral opioid. As an example, if a patient typically consumes 400 mg of oral oxycontin/day, this is the equivalent of 30 mg of intravenous hydromorphone/day. As mentioned previously, we expect that opioid needs will go up by 200–400% in the immediate postsurgical period, so the patient will likely need 60–120 mg of intravenous hydromorphone (Dilaudid®)/24 h. This increased dose of hydromorphone can be administered via an intravenous PCA device programmed to deliver 2.5–5 mg of intravenous hydromorphone per hour. Clinicians are cautioned that opioid conversion is an estimate and careful observation of efficacy and side effects ultimately determines the appropriate conversion.
Determine likely postsurgical opioid requirements (Box 1);
Educate patient about realistic expectations for pain management. Inform patient that the postsurgical dose of opioid will be increased for several days, then weaned back to baseline over 2–3 weeks;
Administer (scheduled, not pro re nata [p.r.n.; when necessary]) nonopioid analgesics, such as acetaminophen, celecoxib, dexamethasone and gabapentin. Some surgeons object to NSAID medications in the setting of spine fusion surgery. However, a recent meta-analysis concludes that standard doses of NSAIDs do not impact spine fusion success rates.
Anesthesiologists must anticipate ongoing opioid needs and much higher opioid requirements postsurgically. Failure to make this adjustment may cause a patient to begin opioid withdrawal in the early postoperative period;
Ketamine bolus and infusion. As described earlier, ketamine is an antagonist at the spinal cord NMDA receptor, which coordinates pain transmission from the periphery to the CNS. In opioid tolerant patients, continuous intraoperative blockade of the NMDA receptor with ketamine significantly lowers pain scores and opioid needs for at least 6 weeks after surgery;
Neuraxial analgesics may be used. During the surgery, the dura is exposed. Injection of intrathecal morphine or placement of an epidural catheter is easily accomplished.
Maximize nonopioid analgesics, such as scheduled acetaminophen and gabapentin;
Give appropriate doses of intravenous opioids. If the patient has renal insufficiency, choose opioids that do not have active metabolites; hydromorphone or fentanyl are good choices. Particularly avoid meperidine, as proconvulsant metabolites can accumulate with even moderate renal impairment;
When conversion back to oral opioids is appropriate, determine last 24 h opioid needs, and use opioid converter to calculate equivalent oral opioid dose. As a general guideline, divide oral opioids into approximately 60–70% scheduled sustained-release opioid (such as extended-release oral morphine), and 30–40% immediate-release opioid given as needed for breakthrough pain;
Wean patient back to baseline (or lower) dose of opioids over 2–3 weeks.
Case 3: Total Abdominal Hysterectomy in 77-year-old Woman
Several types of surgery are noted for a very high rate of long-term incisional pain: hysterectomy, mastectomy, thoracotomy and inguinal herniorrhaphy. All of these procedures involve the frequent laceration of nerves involved in cutaneous sensation. In the case of abdominal hysterectomy, the ilioinguinal nerve is commonly injured or severed.
The pain management of these patients has much in common with other cases, such as using nonopioid analgesics to minimize opioid doses and opioid side effects. However, in procedures that have high rates of cutaneous nerve injury (such as abdominal hysterectomy), there is a particular role for gabapentinoids. Preoperative gabapentin significantly reduces the development of chronic pain after these high-risk surgeries. The optimal dose is 900 mg. Unfortunately, the elderly may have some confusion and gait imbalance for approximately 12–24 h after gabapentin, which merits close observation.
Aging Health. 2011;7(6):813-828. © 2011 Future Medicine Ltd.