Abstracts of Posters Presented at the International Anesthesia Research Society; 72nd Clinical and Scientific Congress; Orlando, FL; March 7-11, 1998: Ambulatory Anesthesia
Recent reports of Transient Radicular Irritation (TRI) after lidocaine spinal anesthesia have raised concerns about potential neurotoxicity . These concerns prompted a reinvestigation of procaine for spinal anesthesia.
METHODS: With approval of the IRB and written consent, 106 consecutive patients scheduled for spinal anesthesia for procedures expected to last <or=to 90 minutes received procaine spinal anesthesia. Plain procaine was used for surgeries expected to last <or=to 45 minutes. In order to prolong surgical anesthesia without unduly prolonging time to discharge from the PACU, we studied the effect of adding fentanyl for surgeries anticipated to last 45 to 90 minutes. In either case, procaine was diluted to 5% concentration before injection.
Intraoperatively the adequacy of duration, level and intensity of anesthesia were observed. In the PACU, the duration of motor block was measured. Three days postoperatively, patients were questioned intensively in an effort to determine whether back pain and/or symptoms consistent with TRI had occurred.
RESULTS: Duration of anesthesia was adequate in all but one instance. The intensity and the sensory level of anesthesia were satisfactory with one exception, a woman who had an unexpectedly low sensory level (L1) after 60 mg of procaine for cerclage, and who was also was the only patient to develop TRI. The incidence of TRI (0.9%) was markedly less than that reported after lidocaine and similar to the incidence observed after bupivacaine [2,3]. Mild back pain without radiation occurred in 11 patients (10%), an incidence which is similar to that seen after bupivacaine and lidocaine. As compared to procaine alone, the addition of fentanyl significantly (P<.0001) prolonged the time to bending knees from 72 minutes to 97 minutes.
CONCLUSIONS: 1) Procaine, with the addition of fentanyl when necessary, is a useful alternative to lidocaine as a spinal anesthetic for surgical procedures lasting less than 90 minutes and is less likely to produce severe radiating back pain (transient radicular irritation). 2) Fentanyl prolongs motor block when added to procaine.
1. Anesth Analg 1993; 76:1154-7
2. Anesth Analg 1996; 83:1051-4
3. Anesthesiology 1996; 84:1361-7