ABSTRACT
The authors developed a new method of intrathecal local anesthetic injection in rabbits in order to study the relationship between anesthetic concentration and impaired neurologic function. They found that none of the local anesthetics studied produced persistent neurologic damage in concentrations used clinically. However, lidocaine and tetracaine can be prepared in high concentrations (far exceeding those clinically used) that will produce extensive irreversible neurologic injury and histologic changes. This was also true for sodium bisulfite, an antioxidant used in a number of commercially prepared local anesthetic solutions. Pure solutions of relatively insoluble local anesthetics (bupivacaine and 2-chloroprocaine) failed to produce comparable neurologic or neuropathologic changes when tested at concentrations up to their solubility limits. Extensive neurologic impairment was not necessarily accompanied by equally extensive lesions in the spinal cord and nerve roots.
Subject(s)
Anesthetics, Local/toxicity , Nerve Block , Spinal Cord/drug effects , Anesthetics, Local/administration & dosage , Animals , Hydrogen-Ion Concentration , Injections, Spinal , Necrosis , Neurologic Examination , Osmolar Concentration , Rabbits , Spinal Cord/pathology , Spinal Nerve Roots/drug effects , Spinal Nerve Roots/pathologySubject(s)
Anesthesia, Epidural/adverse effects , Anesthetics, Local/adverse effects , Arachnoiditis/chemically induced , Paralysis/chemically induced , Procaine/analogs & derivatives , Adult , Anesthetics, Local/administration & dosage , Female , Humans , Procaine/administration & dosage , Procaine/adverse effectsABSTRACT
The effect of progesterone on estrogen-induced uterine blood flow was investigated in repeated experiments in seven nonpregnant, oophorectomized ewes with chronically implanted electromagnetic flow probes and catheters inserted into branches of the uterine arteries. Administered alone, progesterone has no effect on base-line uterine blood flow. Following intramuscular injection of progesterone (3 to 5 mg-per kilogram of body weight), peak uterine blood flow responses to 1 microng of estradiol-17beta were suppressed by 25 per cent compared to those of control animals. Direct intra-arterial infusion of progesterone, at concentrations sufficient to reproduce uterine venous levels observed in late pregnancy in the sheep, inhibited estrogen-induced uterine blood flow by 20 per cent. The findings support the hypothesis that progesterone modulates the estrogen-induced flow responses in both the pregnant and nonpregnant uterine vascular bed.
Subject(s)
Progesterone/pharmacology , Uterus/blood supply , Animals , Estrogen Antagonists , Estrogens/pharmacology , Female , Infusions, Parenteral , Injections, Intramuscular , Pregnancy , Progesterone/administration & dosage , Regional Blood Flow/drug effects , Sheep , Uterus/drug effectsABSTRACT
Well-documented amniotic fluid embolism with survival is an uncommon occurrence. A case is reported with characteristic clinical findings in addition to electrocardiographic evidence of acute right heart strain, disseminated intravascular coagulation, and amniotic fluid debris in central venous blood. The impact of this complication on maternal mortality is emphasized. Aggressive therapy with attention to the basic principles of supportive care offers the best chance of survival.
