Anesthesiology
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It is well known that the concentration of bupivacaine in umbilical cord blood at birth is low compared with the concentration in maternal blood. It is not clear whether this low fetal/maternal ratio (F/M) is due to decreased placental transfer or increased uptake by fetal tissues. The purposes of this study were to develop an appropriate analytic method and to clarify this issue by studying the disposition of bupivacaine in mother, fetus and neonate following epidural anesthesia. ⋯ Finally, urinary excretion of PPX by the neonate remains relatively constant during the first 48 h of life. In contrast, the mother excretes the highest amount of PPX between 12-24 h postpartum. The persistence of bupivacaine and PPX in neonatal body fluids suggests that the low F/M ratio of bupavacaine at birth is due to considerable uptake of bupivacaine by fetal tissues and is not due to diminished placental transfer.
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The incidence of neurologic complications arising from anticoagulant therapy, following epidural and subarachnoid catheterization in 3,164 and 847 patients, respectively, was determined. Twenty patients experienced minor neurologic complications or low back pain which was self-limiting and resolved with time. There was no incidence of peridural hematoma leading to spinal cord compression. This investigation shows that the occurrence of symptomatic hematomas following anticoagulation in patients with epidural or subarachnoid catheters is a very rare complication, assuming proper patient selection, an atraumatic technique, and appropriate monitoring of anticoagulant activity.
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The authors constructed a D-shaped tracheal model with an elastic posterior wall, thus simulating normal tracheal anatomy more closely than previous models. The performance of 9-10 tracheal tube cuffs, of 2-3 different tube sizes (7.0-10.0 mm, ID), from six different manufacturers were tested in the model. Cuff residual volumes ranged from 1.78 to 27.35 ml. ⋯ There was no relationship between cuff brands in the wall pressure required to effect a seal in the model. The authors conclude that intratracheal tubes should have cuffs with large residual volumes. This would permit some latitude in tube size selection while ensuring that a seal could be achieved before the cuff is inflated to its residual volume.