Abstracts of Posters Presented at the International Anesthesia Research Society; 72nd Clinical and Scientific Congress; Orlando, FL; March 7-11, 1998: Ambulatory Anesthesia
Unexpected admissions are a critical quality indicator in the pursuit of a cost-effective anesthetic in ambulatory surgery. The most common causes of unexpected admissions are refractory pain and postoperative nausea/vomiting (PONV).  We developed regional anesthesia clinical pathways (CP) for outpatients undergoing anterior cruciate ligament (ACL) reconstruction of the knee. We demonstrate that these CPs decrease the unexpected admission rate due to these anesthesia-related complications.
Methods: After IRB approval, medical records of outpatients undergoing ACL reconstruction from July 1995 through June 1997 were analyzed for unexpected admissions. In academic year (AY) 1995-1996, no perioperative anesthesia CPs were in place, whereas in AY 1996-1997, CPs encouraging patient selection of regional anesthesia were in place, and patients (in whom no contraindications existed) could select either general anesthesia (GA), GA with femoral nerve block (GFNB), or epidural anesthesia (EA). For the 1996-1997 group, the two regional anesthesia (RA) CPs were pooled into one category for analysis. EA consisted of lumbar epidural catheters placed preoperatively, intraoperative epidural dosing with lidocaine and fentanyl, and sedation with propofol. Both GA and GFNB consisted of endotracheal anesthesia with desflurane, nitrous oxide, and oxygen and opioid analgesia with fentanyl, after induction with propofol and muscle relaxation with succinylcholine. GFNB patients had femoral nerve blocks (with bupivacaine) placed preoperatively. All patients were given intraarticular morphine (10 mg) and bupivacaine (0.5%, 30cc) at the end of the surgical procedure. CP patients undergoing GA, or at risk by history for PONV, were given empiric droperidol and metoclopramide intraoperatively. CP patients with refractory PONV were given a sequence of metoclopramide, droperidol, ondansetron, and perphenazine postoperatively before admission was considered. Admission rate data from historical controls during AY 1995-96 were compared with the 1996-97 CP group, then RA-CP patients were compared with admission rate data in GA-CP patients. The only similarity between the historical controls and the CP patients was the intraarticular injection at the end of the procedure. Admission rates were analyzed using chi-squared analysis, P < 0.05 was considered significant.
Results: Admission rate data from 209 historical controls and 192 CP patients were examined. Patients who were known in advance to be admitted postoperatively, who were admitted because of an extension of the surgical procedure, or who were admitted for reasons unrelated to intractable pain or PONV (e.g., no responsible adult to take the patient home) were excluded from this analysis. Unexpected admissions occurred in 20% (42/209) of the historical controls and in 9% (17/192) of the patients subjected to the anesthesia CPs (P = 0.002). CP patients who underwent GA alone had a higher incidence of unexpected admissions (20%, 8/40) than did RA-CP patients (6%, 9/147, P = 0.002).
Discussion: The intraoperative anesthesia care plans prescribed may have a significant effect on unexpected admission rates after ambulatory surgery for ACL reconstruction, and regional anesthesia may play an important role in reducing admissions. In the managed-care era, both patient satisfaction and the percentage of anesthesia service reimbursements (in capitated environments) after ambulatory surgery are likely to plummet due to unexpected admissions.