Succinylcholine Use and Dantrolene Availability for Malignant Hyperthermia Treatment: Database Analyses and Systematic Review.

BACKGROUND: Although dantrolene effectively treats malignant hyperthermia (MH), discrepant recommendations exist concerning dantrolene availability. Whereas Malignant Hyperthermia Association of the United States guidelines state dantrolene must be available within 10 min of the decision to treat MH wherever volatile anesthetics or succinylcholine are administered, a Society for Ambulatory Anesthesia protocol permits Class B ambulatory facilities to stock succinylcholine for airway rescue without dantrolene. The authors investigated (1) succinylcholine use rates, including for airway rescue, in anesthetizing/sedating locations; (2) whether succinylcholine without volatile anesthetics triggers MH warranting dantrolene; and (3) the relationship between dantrolene administration and MH morbidity/mortality. METHODS: The authors performed focused analyses of the Multicenter Perioperative Outcomes Group (2005 through 2016), North American MH Registry (2013 through 2016), and Anesthesia Closed Claims Project (1970 through 2014) databases, as well as a systematic literature review (1987 through 2017). The authors used difficult mask ventilation (grades III and IV) as a surrogate for airway rescue. MH experts judged dantrolene treatment. For MH morbidity/mortality analyses, the authors included U.S. and Canadian cases that were fulminant or scored 20 or higher on the clinical grading scale and in which volatile anesthetics or succinylcholine were given. RESULTS: Among 6,368,356 queried outcomes cases, 246,904 (3.9%) received succinylcholine without volatile agents. Succinylcholine was used in 46% (n = 710) of grade IV mask ventilation cases (median dose, 100 mg, 1.2 mg/kg). Succinylcholine without volatile anesthetics triggered 24 MH cases, 13 requiring dantrolene. Among 310 anesthetic-triggered MH cases, morbidity was 20 to 37%. Treatment delay increased complications every 10 min, reaching 100% with a 50-min delay. Overall mortality was 1 to 10%; 15 U.S. patients died, including 4 after anesthetics in freestanding facilities. CONCLUSIONS: Providers use succinylcholine commonly, including during difficult mask ventilation. Succinylcholine administered without volatile anesthetics may trigger MH events requiring dantrolene. Delayed dantrolene treatment increases the likelihood of MH complications. The data reported herein support stocking dantrolene wherever succinylcholine or volatile anesthetics may be used.

Time of return of neurologic function after spinal anesthesia for total knee arthroplasty: mepivacaine vs bupivacaine in a randomized controlled trial.

BACKGROUND: Mepivacaine as an intermediate-length spinal anesthetic for rapid recovery in total knee arthroplasty (TKA) has not been fully described. We compared spinal mepivacaine vs bupivacaine for postoperative neurologic function in patients undergoing primary TKA. METHODS: Thirty-two patients undergoing primary TKA were enrolled. Primary outcome measure was return of motor and sensory function. Secondary outcome measures included assessment of urinary function, pain via visual analog scale (VAS) scores, opioid usage, distance walked and pain with physical therapy, time to discharge readiness, and complications. RESULTS: Patients with mepivacaine spinal anesthetic had faster return of sensory function (164 ± 38.6 vs 212 ± 54.2 minutes, P = .015), return of motor function (153 ± 47.4 vs 200 ± 45.2 minutes, P = .025), and time to straight leg raise (148 ± 43.5 vs 194 ± 50.8 minutes, P = .023). The mepivacaine group experienced significantly fewer episodes of urinary retention and shorter time to urination (344 ± 154.4 vs 416 ± 96.3 minutes, P = .039). Patients exhibited slightly higher VAS pain scores in the postanesthesia care unit (1.0 ± 1.7 vs 2.7 ± 2.3, P = .046) with no difference in opioid consumption. There were no differences in VAS scores or opioid use on the inpatient ward. Patients achieved discharge readiness 71 minutes faster in the mepivacaine group. There was no need to convert to general anesthesia or transient nerve symptoms in either group. CONCLUSIONS: Patients undergoing TKA with mepivacaine spinal anesthetic had a reliably more rapid neurologic recovery after TKA compared to bupivacaine.