CHOOSING GENERAL VERSUS REGIONAL ANESTHESIA FOR THE ELDERLY

The surgical patient is actually four distinctly different patients. Patient #1 is the patient whose baseline physiologic and pathologic state is influenced by coexisting disease or injury, social excesses, and physical conditioning prior to the surgical illness. Patient #2 is the preoperative patient who now has a surgical illness superimposed on his/her baseline state. Patient #3 is the intraoperative patient who is experiencing the stress of surgery attenuated by the administration of anesthesia. Patient #4 is the postoperative patient responding to and recovering from the stress of surgery in the absence of anesthesia but in the presence of analgesia. Every day anesthesiologists see patient #2 to decide between regional and general anesthesia for patient #3 and to plan the postoperative management, including analgesia, for patient #4. The goal is the return of patient #1. Ideally, the first decision would be based on the answers to a hierarachy of questions found in the list below. Although the answers to all these questions are still not known, there are significantly more data now available on which to base this decision. The extent to which outcome is based on the management of patients #1, #2, #3, and #4 is now better understood. The purpose of this article is to discuss how and why the perceptions of the relative safety of regional and general anesthesia have changed from the late 1970s to the late 1990s from the perspective of all four of these patients. Hierarchy of Questions to Address in Making the Decision between Regional and General Anesthesia Is one technique safer than the other independent of disease or surgical procedure? Is relative safety independent of disease but dependent on surgical procedure? Is relative safety independent of surgical procedure but dependent on disease? Is relative safety dependent on a specific surgical procedure in the presence of a specific disease? If no applicable studies, does theory (or personal clinical experience) overwhelmingly suggest one technique? If equivalent safety, is one technique less expensive when full cost accounting is used? If equivalent safety and cost, which technique does the patient prefer? If equivalent safety, cost, and patient preference, which technique does the anesthesiologist prefer? The two major theoretic reasons why regional anesthesia should be safer than general anesthesia are: (1) regional anesthesia provides stress-free anesthesia, which is important because many perioperative complications are the consequence of the stress response to surgery, especially in patients with chronic disease; and (2) regional anesthesia prevents central sensitization, or spinal cord "wind-up," and provides preemptive analgesia. An excellent demonstration of stress-free regional anesthesia is provided by Carli and Halliday. 11 They compared combined epidural-general anesthesia and postoperative epidural analgesia with general anesthesia and parenteral analgesia. Their markers for surgical stress were an increase in protein degradation and a decrease in protein synthesis. The patients were continuously nourished and kept normothermic for 48 hours. In the combined epidural-general group the epidural catheter was inserted at T8 and bupivacaine 0.75% was administered to produce and sustain a T3-S5 sensory block for the entire duration of the surgery. Postoperative analgesia was provided with bupivacaine 0.25% continuously administered epidurally for 48 hours at a sufficiently low rate to enable the patients to ambulate, and papaveretum administered intramuscularly. In the continuous epidural anesthesia and analgesia group, the decrease in protein synthesis and increase in protein degradation typically seen was arrested. These 1997 results lend strong theoretic weight to the conclusions drawn from the 1987 landmark study by Yeager et al 66 discussed below, demonstrating better outcomes in high-risk surgical patients who received epidural-general anesthesia and epidural analgesia than in those who received general anesthesia and parenteral analgesia. 2 Excellent demonstrations of regional anesthesia providing preemptive analgesia are provided by Shir et al. 54 and Gottschalk et al 29 in patients undergoing radical prostatectomy. Shir et al 54 divided patients into three groups, epidural-only, epidural-general, and general-only, and examined postoperative pain scores and analgesic requirements. The patients in the epidural-only group received significantly more bupivacaine than those in the epidural-general group intraoperatively. In all patients, postoperative analgesia was provided with epidural patient-controlled analgesia (PCA) with bupivacaine and fentanyl. There was no difference in postoperative epidural PCA demand in the epidural-general and general-only groups, but the PCA demand was significantly less in the epidural-only group. Gottschalk et al 29 designed their study differently. Epidural bupivacaine (20 mL 0.5% bupivacaine with epinephrine 1:200,000 and sodium bicarbonate 0.005 mEq/mL loading dose and 13 mL every 2 hours), epidural fentanyl (20 mL of a solution mixed to provide 4 μg/kg loading dose and 0.75 μg/kg in 13 mL every 2 hours), or no epidural drug was administered prior to the induction of anesthesia and throughout the entire operation. At the beginning of fascial closure, all patients received morphine, 5 mg epidurally, 1 mg/mL mixed with 8 mL of 2% lidocaine. Epidural PCA with morphine and bupivacaine was initiated in all patients. In the epidural bupivacaine preemptive analgesia group, patients experienced significantly less pain than in the control group on postoperative days (PODs) 1 through 4. In the epidural fentanyl preemptive analgesia group, postoperative pain was less but only reached statistical significance on POD 4. Overall, the preemptive analgesia groups combined experienced 33% less pain while hospitalized. At 9.5 weeks, 86% of the preemptive analgesia group patients were pain-free and more active, compared with only 47% in the control group. Significantly less epidural PCA was required in the bupivacaine group than in the control group, but not in the fentanyl group versus control.