Risk of high spinal anesthesia following failed epidural block for cesarean delivery.

Recent case reports suggest there may be an increased risk of abnormally high blockade ("high spinal") from subarachnoid anesthesia if it is performed immediately after epidural anesthesia. We describe two cases of high spinal anesthesia following failed epidural block in obstetric patients scheduled for cesarean delivery. Using a retrospective chart review, we estimate the incidence of high spinal anesthesia to be 11% in patients after prior failed epidural blockade versus fewer than 1% in patients undergoing spinal anesthesia alone.

The frequency of postdural puncture headache in obstetric patients: a prospective study comparing the 24-gauge versus the 22-gauge Sprotte needle.

STUDY OBJECTIVE: To compare the frequency of postdural puncture headache (PDPH) in obstetric patients when using the 24-gauge or the larger 22-gauge Sprotte needle. DESIGN: Prospective, randomized study. SETTING: Four hospitals. PATIENTS: 375 ASA physical status I and II cesarean section and postpartum tubal ligation patients. INTERVENTIONS: Obstetric patients were randomly assigned to receive spinal anesthesia via a midline dural puncture using the 24-gauge or the 22-gauge Sprotte needle. MEASUREMENTS AND MAIN RESULTS: The rate of PDPH was determined by a postoperative visit by the anesthesiologist as well as questioning patients by telephone 1 week or more after discharge. In the 24-gauge Sprotte needle group (n = 186), 2 mild and 1 moderate PDPHs were reported, for an overall rate of 1.61%. In the 22-gauge Sprotte needle group (n = 189), 2 mild and 1 moderate PDPHs were reported, for an overall rate of 1.59%. All headaches except 1 resolved within 72 hours with conservative treatment. One patient from the 22-gauge Sprotte needle group required an epidural blood patch. There were no failed blocks in either group. CONCLUSIONS: Our results suggest that the 22-gauge Sprotte needle, when compared with the smaller 24-gauge Sprotte needle, can be used in obstetric patients without increasing the frequency of PDPH.

Double-blind evaluation of patient-controlled epidural analgesia during labor.

A double-blind randomized study was designed to compare the efficacy of patient-controlled epidural analgesia (PCEA) with continuous epidural analgesia (CEA) with regards to patient satisfaction with analgesia, analgesic efficacy, and local anesthetic usage. After establishing effective epidural analgesia with 8 ml of 0.25% bupivacaine, 39 parturients were randomized to 1 of 2 groups. The CEA group received a continuous infusion of 12 ml/h of 0.125% bupivacaine. The PCEA group received a background infusion of 4 ml/h of 0.125% bupivacaine and were able to self-administer additional boluses of 3 ml of 0.25% bupivacaine every 10 min up to 15 ml/h. In both groups, when patients complained of inadequate analgesia, supplemental doses of 5 ml of 0.25% bupivacaine were administered by a physician. The 2 groups were similar in age, height, weight, gravidity, labor duration, motor block, sensory block, and infant Apgar scores. The 2 groups also did not differ significantly in terms of patient satisfaction, pain assessment, or total drug usage. However, the PCEA group required significantly fewer supplemental doses (15%) compared with the CEA group (40%). The decreased need for supplemental doses in the PCEA group may suggest a potential advantage in consistency of analgesia and possibly decreased man-power needs.

A randomized double-blind comparison of epidural versus intravenous fentanyl infusion for analgesia after cesarean section.

The authors conducted a randomized double-blind controlled study comparing groups of patients receiving iv or epidural fentanyl infusions to determine whether, at comparable levels of analgesia, 1) the severity of side effects was different; and 2) plasma fentanyl concentrations differed between the two groups. Twenty-eight ASA physical status 2 women scheduled to undergo elective cesarean section were randomized into two groups to either receive fentanyl intravenously and saline epidurally or fentanyl epidurally and saline intravenously. After delivery of the infants under epidural anesthesia, each patient received a bolus of fentanyl 1.5 microgram/kg either intravenously or epidurally, and a fentanyl infusion was begun via the same route. Concurrently, a saline bolus and infusion were given via the alternate route. The rates of the fentanyl and saline infusions were adjusted until each patient was comfortable. Patients rated their pain, nausea, and pruritus on visual analogue scales. Sedation was evaluated by an observer. Respiratory depression was evaluated by end-tidal PCO2. Data were analyzed by unpaired two-tail t tests. Plasma fentanyl concentrations were measured at 12 and 24 h. Three patients in the iv group were dropped from the study because of inadequate pain relief. For the remaining 25 patients, similar infusion rates of fentanyl were required to produce similar levels of analgesia at 12 and 24 h. The severity of nausea, pruritus and sedation, and end-tidal PCO2 were similar for both groups. The plasma concentrations of fentanyl were significantly greater in those who received iv fentanyl at 12 h but not at 24 h.(ABSTRACT TRUNCATED AT 250 WORDS)

Successful pregnancy after cardiac transplantation.

A case report of a successful pregnancy after cardiac allotransplantation is presented. The patient underwent transplantation for an inoperable cardiac tumor 5 years before conception. Cardiac function before and during all stages of pregnancy was normal. Maintenance immunosuppressive therapy consisting of prednisone and azathioprine was continued through gestation. The pregnancy was complicated by a primary herpes virus infection requiring parenteral acyclovir treatment and a single episode of preterm labor that was successfully treated. The infant was born at term, weighed 3278 gm, and has developed normally during the first 3 years of life. The patient died 5 months after delivery as a result of an acute immunologic rejection 5 months post partum caused by self-initiated discontinuation of immunosuppressive therapy. Preconceptional counseling and pregnancy care guidelines are discussed.

Life-threatening effects of intravascular absorption of PGF2 alpha during therapeutic termination of pregnancy.

PIP: A case of inadvertent intravascular injection of PGF2alpha during induction of labor by intraamniotic injection for fetal demise, involving alternating extreme hypotension and hypertension, is described. The woman was a 29-year old in late 2nd trimester with oligohydramnios, but no other related history. She was given epidural anesthesia, 7.5 mg midazolam and 5 mg morphine S04 for anxiety. Because of oligohydramnios, 300 ml Ringers lactate was instilled to dilute the PG. A test dose of 1 mg PGF2alpha was tolerated well. 80 g urea and 20 mg PGF2alpha were injected over 10 minutes. A few minutes later contractions began, followed by complaints of burning on face and chest and dyspnea. Oxygen was given by mask. Systolic pressure fell to 70 mm by cuff; peripheral pulses could not be palpated, but the patient remained alert and oriented. She was given 35 mg ephedrine and increased iv fluids. She remained dyspneic, her extremities became mottled, and she complained of chest pressure, severe headache and severe breast tenderness. Blood pressure rose to 220/135 mm Hg; pulse to 95, and respiratory rate to 44. Pulse oximetry, detectable at the earlobe only, was 94% saturation. After 50 mg labetalol, blood pressure fell to 134/77, but symptoms remained. For 2 hours blood pressure swung between 76/50 and 225/125, until delivery of the fetus. An arterial line could not be started because of extreme vasoconstriction. Central venous pressure was 13 cm H20. After artificial rupture of the membranes and removal of remaining PG, blood pressure stabilized. Delivery was accomplished without incident. The symptoms and labile blood pressure were considered to be due to intravascular injection of PGF2alpha, caused by repeated bolus injection at each uterine contraction. In case of PG induction for fetal demise, it is recommended that anesthesiologists be prepared to treat intravascular collapse, hypertension and bronchoconstriction.^ieng

Anesthesia for cesarean delivery.

The available options for cesarean section anesthesia are spinal, epidural, and general anesthesia. Each method has been enhanced over the years to provide better operating conditions and increased maternal and fetal safety. The choice is made primarily by the requirements of the situation as each can be provided with nearly equivalent safety by today's obstetric anesthesiologist.

The role of 2-chloroprocaine and sodium bisulfite in rat sciatic nerve edema.

In order to evaluate the possible mechanisms of local anesthetic toxicity, the rat sciatic nerve was exposed to various solutions including Nesacaine (containing the antioxidant sodium bisulfite), 2-chloroprocaine in the Nesacaine vehicle (0.2% sodium chloride), 0.2% sodium bisulfite in 0.2% sodium chloride, or 0.2% sodium chloride alone. All solutions were pH balanced between 2.9 and 3.2. Forty-eight hours (h) following extraneural administration of 1 ml volumes, significant edema was produced by all solutions containing 3% 2-chloroprocaine, but not with 0.2% bisulfite in sodium chloride or with sodium chloride alone. Intrafascicular administration of five to ten microliter volumes of these solutions produced edema at 48 h in all cases, but the highest levels were observed with Nesacaine and the lowest levels with 0.2% bisulfite. The results of this study implicate the local anesthetic 2-chloroprocaine in the production of nerve edema, which is inconsistent with other reports that the toxicity of Nesacaine-CE can be attributed to the antioxidant bisulfite.

Neurotoxicity of local anesthetics: altered perineurial permeability, edema, and nerve fiber injury.

A quantitative, in situ experimental method was developed employing the rat sciatic nerve to study the neurotoxicity of local anesthetic solutions applied directly to an intact peripheral nerve bundle. One-milliliter volumes of 2-chloroprocaine, 3%; tetracaine, 1%; lidocaine, 2%; bupivacaine, 0.75%; or sodium chloride, 0.2%; were injected with a 30-gauge needle beneath the mesoneurium but exterior to the epineurium. The wound was closed and the animals were normally maintained until the nerves were reexposed for quantitative biophysical and morphologic testing 24 h to 4 weeks later. The results indicate that topically applied 2-chloroprocaine and tetracaine produce significant endoneurial edema 48 h after treatment. Horseradish peroxidase was used to verify increased permeability of the perineurium. Endoneurial fluid pressure was significantly increased in edematous nerves. Electron microscopy revealed abnormal mast cells and proliferation of endoneurial fibroblasts in addition to Schwann cell injury and axonal dystrophy. This study shows that extrafascicular administration of clinically used concentrations of local anesthetic solutions can alter perineurial permeability, producing changes in the endoneurial environment that are associated with neurotoxic injury. Perineurial and endoneurial fibrotic changes may be a late consequence of peripheral nerve injury with anesthetic solutions producing altered perineurial permeability with endoneurial edema.

Evaluation of the use of continuous lumbar epidural anesthesia for hypertensive pregnant women in labor.

The use of continuous lumbar epidural anesthesia in women with pregnancy-induced hypertension remains controversial. We retrospectively reviewed the charts of 285 women with pregnancy-induced hypertension who were delivered in a 2-year period. Among 185 vaginally delivered patients who received continuous lumbar epidural or local anesthesia, there were no significant differences in the incidence of maternal hypotension, abnormal fetal heart rate tracings, low Apgar scores, or neonatal intensive care unit admissions. Of 100 patients delivered by cesarean section, the incidence of low Apgar scores, depressed umbilical cord pH values, and neonatal intensive care unit admission was increased among those who received general anesthesia (p less than 0.05). However, general anesthesia patients were more likely to have abnormal fetal heart rate tracings (27% versus 4%) requiring urgent delivery. Thus differences in outcome probably reflect poorer fetal condition prior to anesthesia induction rather than a specific anesthetic effect. These results demonstrate that continuous lumbar epidural anesthesia is safe and effective for both the fetus and the mother with pregnancy-induced hypertension.