Meningitis or epidural abscesses after neuraxial block for removal of infected hip or knee prostheses.

BACKGROUND: Infection, whether localized or systemic, can be a relative contraindication to neuraxial anaesthesia. Data correlating neuraxial anaesthesia and the development of meningitis or epidural abscess in this setting are limited. METHODS: Retrospective chart review was performed on 710 medical records of patients admitted between 1998 and 2009 for removal of potentially infected total hip and total knee prostheses. Ultimately, 474 patients were identified as being infected. Factors that predisposed a patient to an immunocompromised state, and signs and symptoms of infection in the pre-, intra-, and postoperative stages were documented. Bacteraemic patients were reviewed for signs of neuraxial infection. The endpoint of follow-up was development of complications before hospital discharge. RESULTS: All 474 patients had removal of the infected prosthesis under neuraxial anaesthesia. Mean patient age was 65.5 yr (58% >65 yr) and mean length of hospital stay was 21 days. Patient characteristics included concurrent disease (65%), steroid use (5.3%), preoperative antibiotic use (50.8%), signs of inflammatory process (84%), bacteraemia (4.2%), and documented positive intraoperative joint cultures (88%). Using clinical standards for diagnosis of central neuraxial infection, patients developed infectious complications (incidence of 0.6% on 95% confidence interval), although three patients had findings attributable to anaesthesia, including epidural haematoma, psoas abscess, and back pain. CONCLUSIONS: Based on clinical criteria, our findings suggest that the incidence of central nervous system infection after neuraxial anaesthesia in patients with infected hip and knee prostheses is low after neuraxial block.

Dose response relationships for isobaric spinal mepivacaine using the combined spinal epidural technique.

UNLABELLED: Mepivacaine, a local anesthetic with similar physiochemical properties to those of lidocaine, is an adequate alternative for patients undergoing ambulatory procedures, and is associated with a lower incidence of transient neurologic symptoms (TNS) than lidocaine. We studied the dose-response characteristics of isobaric intrathecal mepivacaine using the combined spinal epidural technique for patients undergoing ambulatory arthroscopic surgery of the knee. Seventy-five patients were randomized prospectively to receive one of three doses of isobaric mepivacaine for spinal anesthesia: 30 mg (2 mL 1.5%), 45 mg (3 mL 1.5%), or 60 mg (4 mL 1.5%). An observer, blinded to the dose, recorded sensory level to pinprick and motor response until resolution of the block. In addition, the incidence of TNS was determined. An initial intrathecal dose of 30 mg of isobaric mepivacaine 1.5% produced satisfactory anesthesia in 72% of ambulatory surgical patients undergoing unilateral knee arthroscopy with a significantly shorter duration of sensory (158 +/- 32 min) and motor blockade (116 +/- 38 min) than doses of 45 and 60 mg. An intrathecal dose of 45 mg produced satisfactory anesthesia in all patients with a shorter duration of sensory (182 +/-38 min) and motor blockade (142 +/- 37 min) than 60 mg of mepivacaine 1.5% (203 +/- 36 min and 168 +/- 36 min, respectively). The incidence of TNS was 7.4% overall (1.2%-13.6% confidence intervals), less than the rates previously reported after spinal anesthesia with lidocaine in ambulatory surgical patients undergoing knee arthroscopy. We conclude that mepivacaine can be used as an adequate alternative to lidocaine for ambulatory procedures. IMPLICATIONS: This study evaluated the postoperative duration of spinal anesthesia after varying doses of isobaric mepivacaine and the incidence of transient radiating back and leg pain. We found that 45 mg of mepivacaine provided adequate anesthesia, a timely discharge, and a lower incidence of back pain than that previously reported after lidocaine spinals.

Randomized trial of hypotensive epidural anesthesia in older adults.

BACKGROUND: Data are sparse on the incidence of postoperative cognitive, cardiac, and renal complications after deliberate hypotensive anesthesia in elderly patients. METHODS: This randomized, controlled clinical trial included 235 older adults with comorbid medical illnesses undergoing elective primary total hip replacement with epidural anesthesia. The patients were randomly assigned to one of two levels of intraoperative mean arterial blood pressure management: either to a markedly hypotensive mean arterial blood pressure range of 45-55 mmHg or to a less hypotensive range of 55-70 mmHg. Cognitive outcome was assessed by within-patient change on 10 neuropsychologic tests assessing memory, psychomotor, and language skills from before surgery to 1 week and 4 months after surgery. Prospective standardized surveillance was performed for cardiovascular and renal outcomes, delirium, thromboembolism, and blood loss and replacement. RESULTS: The two groups were similar at baseline in terms of age (mean, 72 yr), sex (50% women), comorbid conditions, and cognitive function. After operation, no significant differences in the incidence of early or long-term cognitive dysfunction were observed between the two blood pressure management groups. There were no significant differences in the rates of other adverse consequences, including cardiac, renal, and thromboembolic complications. In addition, no differences occurred in the duration of surgery, intraoperative estimated blood loss, or transfusion rates. CONCLUSIONS: Elderly patients can safely receive controlled hypotensive epidural anesthesia with this protocol. There was no evidence of greater risks, or early benefits, with the use of the more markedly hypotensive range.

The use of metoprolol and glycopyrrolate to prevent hypotensive/bradycardic events during shoulder arthroscopy in the sitting position under interscalene block.

UNLABELLED: Sudden profound hypotensive and/or bradycardic events (HBE) have been reported in >20% of patients undergoing shoulder arthroscopy in the sitting position under interscalene block anesthesia. Retrospective studies suggest that the administration of beta-blockers is safe and may decrease the incidence of these episodes. We performed a randomized, prospective study to evaluate prophylaxis of these events. One hundred fifty patients were randomized to one of three groups (placebo; prophylactic metoprolol to achieve a heart rate <60 bpm or a maximal dose of 10 mg; or prophylactic glycopyrrolate to achieve a heart rate >100 bpm or a maximal dose of 6 microg/kg) immediately after the administration of the interscalene block. Blood pressure control was achieved with IV enalaprilat as needed. The incidence of HBE was 28% in the placebo group versus 5% in the metoprolol group (P = 0.004). The rate of 22% in the glycopyrrolate group was not significantly different from placebo. Preoperative heart rate and arterial blood pressure, intraoperative sedation score, IV fluids, and enalaprilat use were similar in those patients who had a HBE compared with those who did not. Many aspects of this clinical setting are similar to tilttable testing for patients with recurrent vasovagal syncope, in which beta-adrenergic blockade with metoprolol has also been shown to be effective. We conclude that the Bezold-Jarisch reflex is the most likely mechanism for these events. IMPLICATIONS: Episodes of acute hypotension and bradycardia occur during shoulder arthroscopy in the sitting position under interscalene block. In this study, we demonstrate that metoprolol, but not glycopyrrolate, markedly decreases the incidence of these episodes when given prophylactically immediately after the administration of the block.

Repeated episodes of transient radiating back and leg pain following spinal anesthesia with 1.5% mepivacaine and 2% lidocaine.

BACKGROUND AND OBJECTIVES: Transient radiating back and leg pain defined as pain or dysesthesias in the buttocks, thighs, or calves within 24 to 48 hours after recovery from spinal anesthesia has been described with the use of 2% and 5% lidocaine. These symptoms have also been associated with other local anesthetics such as bupivacaine and tetracaine, although with a much lower incidence. A recent case report and prospective study have described transient radiating back and leg pain occurring following spinal anesthesia with 4% mepivacaine. METHODS: We describe a case of transient radiating back and leg pain following spinal anesthesia with 1.5% mepivacaine in a patient with unrecognized spinal stenosis who had had repeated episodes of transient radiating back and leg pain associated with lidocaine spinals. RESULTS: Spinal anesthesia with 1.5% mepivacaine was associated with transient radiating back and leg pain, which was similar in quality and duration to prior episodes following spinal anesthesia with lidocaine. CONCLUSIONS: Transient radiating back and leg pain may occur with lower concentrations (1.5%) of mepivacaine, as it does with lidocaine. The relationship between transient radiating back and leg pain and spinal stenosis is also discussed.

Transient neurologic symptoms after spinal anesthesia with mepivacaine and lidocaine.

BACKGROUND: Spinal anesthesia with lidocaine is ideal for ambulatory surgery because of its short duration of action. However, transient neurologic symptoms (TNS) occur in 0-40% of patients. The incidence of TNS with mepivacaine, which has a similar duration of action, is unknown. METHODS: Sixty ambulatory patients undergoing knee arthroscopy received spinal anesthesia in a randomized, double-blinded manner, with either 45 mg 1.5% mepivacaine or 60 mg 2% lidocaine. An L3-L4 midline approach was used with a 27-gauge Whitacre needle and a 20-gauge introducer. The local anesthetic was injected over approximately 30 s with the aperture of the Whitacre needle in a cephalad direction. Two to 4 days after operation, each patient was questioned about the development of TNS. In addition, the two groups were compared for time to regression of sensory and motor blockade and time to discharge milestones. RESULTS: Three patients receiving lidocaine were lost to follow-up. None of the 30 patients in the mepivacaine group developed TNS, whereas 6 of 27 (22%) in the lidocaine group did (P = 0.008). Time to regression to the L5 sensory level and to complete resolution of motor block were similar in both groups. The times to discharge milestones were also comparable. CONCLUSIONS: The incidence of TNS is greater with 2% lidocaine than with 1.5% mepivacaine for patients having unilateral knee arthroscopy under spinal anesthesia. Mepivacaine seems to be a promising alternative to lidocaine for outpatient surgical procedures because of its similar duration of action. Further studies are warranted to determine the optimal dose of intrathecal mepivacaine for ambulatory surgery and the incidence of TNS with other doses and concentrations of intrathecal mepivacaine.