Serious Complications Related to Regional Anesthesia

Background Serious complications related to regional anesthesia have previously been described primarily in case reports and retrospective surveys. The authors prospectively evaluated a multicenter series of regional anesthetics, using preplanned criteria to measure the incidence and characteristics of associated serious complications. Methods Requests were sent to 4,927 French anesthesiologists in advance of a subsequent 5-month study period. Participating anesthesiologists were asked for detailed reports of serious complications occurring during or after regional anesthetics performed by them during the study interval. Details regarding each complication then were obtained via a second questionnaire. Results The number of responding anesthesiolgists was 736. The number of regional anesthetics performed was 103,730, corresponding to 40,640 spinal anesthetics, 30,413 epidural anesthetics, 21,278 peripheral nerve blocks, and 11,229 intravenous regional anesthetics. Reports of 98 severe complications were received, with follow-up information being obtained for 97. In 89 cases, complications were attributed fully or partially to regional anesthesia. Thirty-two cardiac arrests, seven of which were fatal, occurred during the study. Of these, 26 occurred during spinal anesthesia, with 6 being fatal, 3 occurred during epidural anesthesia, and 3 more occurred during peripheral blocks. The higher incidence of cardiac arrest during spinal anesthesia (6.4 +/- 1.2 per 10,000 patients) compared with all other regional anesthesia (1.0 +/- 0.4 per 10,000 patients) was statistically significant (P < 0.05). Of 34 neurologic complications (radiculopathy, cauda equina syndrome, paraplegia), 21 were associated either with paresthesia during puncture (n = 19) or with pain during injection (n = 2), suggesting nerve trauma or intraneural injection. Twelve patients who had neurologic complications after spinal anesthetics had no paresthesia during needle placement and no pain on injection. Of these 12 patients (7 with radiculopathy and 5 with cauda equina syndrome), 9 received intrathecal hyperbaric lidocaine, 5%. The incidence of neurologic injury was significantly greater after spinal anesthesia (6 +/- 1 per 10,000 cases; P < 0.05) than after each of the other types of regional procedures (1.6 +/- 0.5 per 10,000 cases for the weighted average). Seizures attributed to elevated serum levels of local anesthetics occurred in 23 patients, but none suffered a cardiac arrest. Conclusions (1) The incidence of cardiac arrest and neurologic injury related to regional anesthesia were very low, but both were more than three SDs greater after spinal anesthesia than after other regional procedures. (2) Two thirds of the patients with neurologic deficits had either a paresthesia during needle placement or pain on injection. (3) Seventy-five percent of the neurologic deficits after nontraumatic spinal anesthesia occurred in patients who had received hyperbaric lidocaine, 5%.