Anesthesiology
-
Dexmedetomidine reduces cerebral blood flow (CBF) in humans and animals. In animal investigations, cerebral metabolic rate (CMR) was unchanged. Therefore, the authors hypothesized that dexmedetomidine would cause a decrease in the CBF/CMR ratio with even further reduction by superimposed hyperventilation. This reduction might be deleterious in patients with neurologic injuries. ⋯ The predicted decrease in CBFV/CMRe ratio was not observed because of an unanticipated reduction of CMRe and a decrease in the slope of the Paco2-CBFV relation. CBFV and Bispectral Index increases during arousal for hyperventilation at 1.2 ng/ml suggest that CMR-CBF coupling is preserved during dexmedetomidine administration. Further evaluation of dexmedetomidine in patients with neurologic injuries seems justified.
-
Randomized Controlled Trial Multicenter Study
A randomized, double-masked, multicenter comparison of the safety of continuous intrathecal labor analgesia using a 28-gauge catheter versus continuous epidural labor analgesia.
Continuous intrathecal labor analgesia produces rapid analgesia or anesthesia and allows substantial flexibility in medication choice. The US Food and Drug Administration, in 1992, removed intrathecal microcatheters (27-32 gauge) from clinical use after reports of neurologic injury in nonobstetric patients. This study examined the safety and efficacy of a 28-gauge intrathecal catheter for labor analgesia in a prospective, randomized, multicenter trial. ⋯ Providing intrathecal labor analgesia with sufentanil and bupivacaine via a 28-gauge catheter has an incidence of neurologic complication less than 1%, and produces better initial pain relief and higher maternal satisfaction, but is associated with more technical difficulties and catheter failures compared with epidural analgesia.
-
Mutations in the skeletal muscle ryanodine receptor gene may result in altered calcium release from sarcoplasmic reticulum stores, giving rise to malignant hyperthermia (MH). MH is a pharmacogenetic skeletal muscle disorder triggered by volatile anesthetics and depolarizing muscle relaxants. Diagnosis of MH is by in vitro contracture testing of quadriceps muscle. DNA analysis of causative mutations is limited by the large number of mutations that cosegregate with MH and the relatively few that have been biochemically characterized. ⋯ DNA analysis to detect mutations which cosegregate with MH as well as biochemical assays on cultured lymphocytes obtained from blood can serve as useful diagnostic tools for MH susceptibility and genotype-phenotype correlations.
-
DESPITE the known benefits of regional anesthesia for patients undergoing joint arthroplasty, the performance of peripheral nerve blocks in patients with multiple sclerosis (MS) remains controversial. MS has traditionally been described as an isolated disease of the central nervous system, without involvement of the peripheral nerves, and peripheral nerve blockade has been suggested to be safe. ⋯ This makes it difficult to provide adequate "informed consent" to these patients. This case report describes a patient with MS who sustained a severe brachial plexopathy after a total shoulder arthroplasty during combined general anesthesia and interscalene nerve block.