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Biomedical subjects

A M Bader

Publications and source records attributed to A M Bader.

36 records · Page 2Linked to original sources
PubMed1993

Anesthesia for in vitro fertilization: a comparison of 1.5% and 5% spinal lidocaine for ultrasonically guided oocyte retrieval.

In many institutions, spinal anesthesia is used for surgery involving ultrasonically guided transvaginal oocyte retrieval. Because this relatively short procedure is performed on an outpatient basis, the optimal spinal technique would allow good surgical anesthesia with a short recovery time. The relative regression of equal doses of different concentrations of hyperbaric spinal lidocaine is presented. We compared 1.5% and 5% hyperbaric lidocaine (7.5% dextrose) as spinal drugs for use in this procedure. Fifty-six patients were randomized to receive 60 mg of hyperbaric solutions of either 1.5% or 5% lidocaine in combination with 10 micrograms of spinally administered fentanyl. Visual analog scale pain scores were zero throughout the procedures for all patients. There were no significant differences between the groups with regard to sensory level, maximum motor block, intravenous sedation requirements, time to two-segment regression, and time to full sensory recovery. The group receiving 1.5% lidocaine had significantly shorter times to ambulation (141 +/- 21 min vs 162 +/- 29 min; P < 0.05), voiding (147 +/- 21 min vs 174 +/- 28 min; P < 0.05), full motor recovery (86 +/- 21 min vs 111 +/- 22 min; P < 0.0001), and discharge (170 +/- 38 min vs 201 +/- 41 min; P < 0.05). The use of 1.5% hyperbaric lidocaine for transvaginal oocyte retrieval provides a significantly shorter recovery time when compared to 5% hyperbaric lidocaine and is a good choice for spinal anesthesia for this procedure.

Anesthesia, Spinal↗
PubMed1992

Continuous epidural infusion of alfentanil and bupivacaine for labor and delivery.

The purpose of this study was to compare alfentanil and fentanyl used in combination with bupivacaine in a continuous infusion epidural technique during labor and delivery. Thirty nine ASA I parturients had epidural analgesia induced with 0.25% bupivacaine and were then assigned in a randomized double-blind fashion to receive a continuous infusion of 0.125% bupivacaine containing either 5 micro/ml of alfentanil or 2 micro/ml of fentanyl at a rate of 10 ml/h. Analgesia assessed by visual analog scores was significantly better during both stage I and stage II of labor in the group receiving alfentanil. No significant maternal or neonatal side-effects were demonstrated.

Journal Article↗
PubMed1991

Maternal temperature regulation during extradural analgesia for labour.

We have studied the effect of analgesia on maternal temperature (oral and tympanic membrane) progression in 53 women during normal spontaneous labour. Three groups were studied: two received extradural analgesia with a continuous infusion of 0.25% bupivacaine with or without the addition of fentanyl; the third group received only parenteral opioid analgesia. All patients were afebrile and without clinical evidence of infection at the beginning of the study. Both groups of patients receiving extradural analgesia had a consistent and significant increase in temperature after approximately 5 h of analgesia; no such trend was observed in the parenteral opioid group. Alterations in mechanisms of heat dissipation may explain these findings.

Adolescent↗
PubMed1991

Maternal and fetal plasma atrial natriuretic peptide concentrations during elective caesarean section.

Atrial natriuretic peptide (ANP) is stored in the atrial cardiocyte and is capable of exerting potent, selective, and transient effects on fluid and electrolyte balance and on blood pressure. Because fluid shifts and hemodynamic adjustments occur during parturition, ANP might play a homeostatic role in the parturient and fetoplacental unit. We measured maternal and fetal plasma ANP concentrations in 19 parturients during elective caesarean section. Plasma ANP levels were also measured in seven nonpregnant women of the same age group. The baseline ANP concentration in parturients was significantly higher (29.77 +/- 6.06 pg/ml vs 7.37 +/- 2.1 pg/ml; mean +/- s.e.mean) than in their nonpregnant counterparts. The umbilical artery (UA) ANP concentration was significantly higher than the umbilical vein concentration (91.91 +/- 14.91 pg/ml vs. 40.04 +/- 9.71 pg/ml). Factors under the anaesthesiologist's control may influence maternal and fetal plasma ANP levels. There was a significant correlation between the volume of maternal Ringer's lactate infusion received and maternal ANP concentration. A significant correlation was seen between the total dose of ephedrine administered acutely prior to delivery and the UA ANP concentration. These data suggest that: 1) increased blood volume during pregnancy is associated with increased maternal plasma ANP levels, and 2) the fetus can produce its own ANP, and is thereby capable of responding to ANP stimulating factors.

Anesthesia, Obstetrical↗
PubMed1990

A new local anesthetic, ropivacaine. Its epidural effects in humans.

The current study was initiated to evaluate the epidural anesthetic properties of 0.5%, 0.75%, and 1.0% ropivacaine, a new local anesthetic agent structurally similar to bupivacaine. Fifteen patients scheduled for lower limb orthopedic surgery were enrolled in the study. As the concentration of ropivacaine increased from 0.5% to 1.0%, the time to onset of sensory anesthesia decreased from 6.4 +/- 1.7 (SD) min to 2.4 +/- 0.6 min and the maximum level of sensory anesthesia increased from T6 to T1. These changes were not statistically significant. Time to regression of anesthesia to T12 increased from 255 +/- 73 min with the 0.5% solution to 356 +/- 75 min with 1.0% ropivacaine (P less than 0.05). The degree of motor blockade using the Bromage scale varied with the concentration. When the 0.5% concentration was used, only one patient (20%) had greater than 1+ motor blockade. However, all of the patients receiving the 0.75% or 1.0% solution had at least 2+ motor blockade. Sensory anesthesia was adequate for surgery in 14 of the 15 patients. The mean peak plasma concentration of ropivacaine (Cmax) increased from 0.65 +/- 0.15 micrograms/mL with the 100-mg dose to 1.30 +/- 0.43 microgram/mL with the 200-mg dose. No adverse effects were noted in any patient in the study. These initial studies in humans suggest that ropivacaine provides satisfactory sensory anesthesia with minimal motor blockade at a concentration of 0.5%. An increase in concentration resulted in a more profound motor blockade. The Cmax of ropivacaine in this study was below levels associated with toxicity in animal studies.

Adult↗
PubMed1990

Acute progesterone treatment has no effect on bupivacaine-induced conduction blockade in the isolated rabbit vagus nerve.

Pregnancy decreases anesthetic requirements during regional anesthesia. Using an in vitro animal model, this study attempts to elucidate the mechanism of hormonal effects on nerve conduction in desheathed rabbit vagus nerve. The acute effects of progesterone administration on neural blockade induced by bupivacaine were investigated in terms of changes in compound action potentials of A, B, and C fibers. No change in baseline compound action potential was found after 30 min of perfusion of the nerve with progesterone. Exposure of the nerve to progesterone before exposure to bupivacaine did not significantly increase the degree of conduction blockade produced by bupivacaine, and a radioactive assay demonstrated that progesterone was taken up acutely by neural tissue over a 45-min measurement period. These results indicate that although progesterone was taken up in significant amounts by neural tissue, an acute exposure does not increase the sensitivity of the nerves to bupivacaine. Hence, the increased sensitivity of nerves to local anesthetics seen with pregnancy or with chronic progesterone treatment requires some period of time to occur. The mechanism is therefore unlikely to be a direct effect of progesterone on the cell membrane but may involve hormonal effects on protein synthesis.

Animals↗
PubMed1990

Maternal and fetal catecholamines and uterine incision-to-delivery interval during elective cesarean.

The fetal sympathoadrenal system is activated during periods of intrauterine stress such as inadequate uterine perfusion. During cesarean, the period of interruption of utero-placental blood flow is extended as the time interval from uterine incision to delivery increases. An increasing uterine incision-to-delivery interval with spinal or general anesthesia has been associated with a poorer neonatal outcome. This association has not been demonstrated previously in patients undergoing cesarean delivery under epidural anesthesia. We investigated the correlation between prolonged uterine incision-to-delivery intervals, fetal catecholamine concentrations, and fetal blood gas values at delivery in 25 parturients undergoing cesarean under epidural anesthesia and in 28 under spinal anesthesia. Infants delivered after prolonged uterine incision-to-delivery intervals had significantly lower pH values in both the epidural and spinal groups. With longer uterine incision-to-delivery intervals, umbilical arterial norepinephrine concentrations were increased significantly. Umbilical arterial pH values were significantly lower in infants with higher umbilical arterial catecholamine concentrations. The importance of minimizing the uterine incision-to-delivery interval, regardless of the type of anesthetic selected, is demonstrated.

Anesthesia, Epidural↗
PubMed1989

Perioperative analgesia with subarachnoid fentanyl-bupivacaine for cesarean delivery.

Addition of fentanyl to bupivacaine administered for spinal anesthesia for cesarean delivery was evaluated in 56 ASA physical status 1 term parturients. Preservative-free saline was added to 0, 2.5, 5, 6.25, 12.5, 25, 37.5, or 50 micrograms fentanyl to make a 1 ml total volume, which was injected intrathecally prior to bupivacaine in a double-blind, randomized fashion. Vital signs, sensory level, motor block, pain score, and side effects were recorded every 2 min for the first 12 min and then at 15, 30, 45, and 60 min and at 30-min intervals until the patient complained of pain. At delivery maternal vein, umbilical artery, and umbilical vein blood gases were obtained. Apgar scores at 1 and 5 min were recorded. Early Neonatal Neurobehavioral Scales (ENNS) were performed on days 1 and 2. Side effects and opioid requirements were recorded for the first 24 h. All of the patients in the control group reported a pain score greater than 0 during surgery and 67% required intraoperative opioids. None of the patients who received greater than or equal to 6.25 micrograms fentanyl required intraoperative opioids. Complete analgesia (time from injection to first report of pain) lasted 33.7 +/- 30.8 min (mean +/- SD) in the control group and increased to 130 +/- 30 min (P less than 0.05) with addition of 6.25 micrograms fentanyl. Duration of effective analgesia (time from injection to first parenteral opioid) was 71.8 +/- 43.2 min in the control group and increased (P less than 0.05) to 192 +/- 74.9 min with addition of 6.25 micrograms fentanyl.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1989

Comparison of bupivacaine- and ropivacaine-induced conduction blockade in the isolated rabbit vagus nerve.

Ropivacaine (LEA-103) is a new amino-amide local anesthetic agent the chemical structure and anesthetic properties of which are similar to bupivacaine. Preliminary studies in animals indicate that the CNS toxicities of ropivacaine and bupivacaine are similar, but that ropivacaine may have less arrhythmogenic effects than bupivacaine. The current study arrhythmogenic effects than bupivacaine. The current study was designed to compare the in vitro potency, onset and recovery from block of ropivacaine and bupivacaine using an isolated rabbit vagus nerve model. The effect of varying concentrations of ropivacaine and bupivacaine on the compound action potential of A and C nerve fibers was assessed to determine whether motor and sensory fibers have different sensitivities to the two agents. The results showed that the depressant effect of bupivacaine was 16% greater than that of ropivacaine on motor fibers, but only 3% greater on sensory fibers. An analysis of variance indicated that this was a statistically significant difference (P = 0.028). Thus, at the concentrations tested, ropivacaine appears to produce relatively less blockade of motor fibers than does bupivacaine but with similar sensory blockade. The onset of this difference became significant as early as five minutes after the drug exposure was begun. No significant differences in recovery times were observed.

Action Potentials↗
PubMed1988

Anesthesia for the obstetric patient with multiple sclerosis.

Data on all obstetric patients delivering at the Brigham and Women's Hospital during the years 1982 through 1987 were collected. The anesthetic techniques used, the type and amount of anesthetic agents administered, and the postpartum relapse rate of multiple sclerosis patients were compared. Women who received epidural anesthesia for vaginal delivery did not have a significantly higher incidence of relapse than those who received local infiltration. However, all of the women who experienced postpartum relapses had received concentrations of bupivacaine greater than 0.25%. This finding may suggest that a higher concentration of drug over a longer period of time may adversely influence the relapse rate.

Anesthesia, Epidural↗
PubMedDate not supplied

Phenylephrine in the prevention of hypotension following spinal anesthesia for cesarean delivery.

STUDY OBJECTIVE: Phenylephrine and ephedrine were compared in the prevention of maternal hypotension following spinal anesthesia for elective cesarean delivery. DESIGN: Randomized, double-blind trial. SETTING: Obstetric suite at a university-affiliated hospital. PATIENTS: Sixty healthy patients electively scheduled for cesarean delivery under spinal anesthesia. INTERVENTIONS: Patients were randomly assigned to receive either ephedrine (n = 29) in 10 mg intravenous (IV) bolus injections or phenylephrine (n = 31) in 80 microgram IV bolus injections to maintain systolic blood pressure (SBP) above 100 mmHg. MEASUREMENTS AND MAIN RESULTS: Maternal venous, umbilical artery, and umbilical vein blood gases were measured, and neonatal Apgar scores and Early Neonatal Neurobehavior Scale scores were assessed. In the ephedrine group, umbilical artery pH was 7.28 +/- 0.01 (mean +/- SEM), umbilical artery partial pressure of carbon dioxide (PCO2) was 56.6 +/- 1.4 mmHg, and umbilical artery base deficit was 2.2 +/- 0.04 meq. In the phenylephrine group, umbilical artery pH was 7.32 +/- 0.01, umbilical artery PCO2 was 52.1 +/- 1.3 torr, and umbilical artery base deficit was 0.38 +/- 0.35 meq. There were significant differences between the groups in mean umbilical artery pH, PCO2, and base deficit, although all values obtained were within normal limits. There were no significant differences between the groups in the remaining acid-base values, neonatal Apgar scores, Early Neonatal Neurobehavior Scale scores, or frequency of maternal nausea and vomiting. CONCLUSIONS: Phenylephrine is as effective as ephedrine in the treatment of maternal hypotension, and when used in small incremental bolus injections, it appears to have no adverse neonatal effects in healthy, nonlaboring parturients.

Anesthesia, Obstetrical↗
PubMedDate not supplied

Intrathecal low-dose bupivacaine versus lidocaine for in vitro fertilization procedures.

BACKGROUND AND OBJECTIVES: Recent controversy with the use of intrathecal lidocaine has prompted the search for suitable ambulatory surgery alternatives. The purpose of our study was to evaluate the clinical utility of intrathecal low-dose bupivacaine for outpatient transvaginal oocyte retrieval. METHODS: Forty women enrolled and completed our prospective, randomized, double-blinded study of intrathecal hyperbaric bupivacaine 3.75 mg (0.5 mL of 0.75%) with fentanyl 25 microg versus hyperbaric lidocaine 30 mg (2.0 mL of 1.5%) with fentanyl 25 microg. Onset and level of sensory and motor block; time to ambulation, urination, and discharge; and intra- and postoperative complications (hypotension, pruritus, nausea, emesis, postdural puncture headache, post spinal pain syndrome [PSPS]) were recorded. Data were evaluated using analysis of variance, chi-squared, and Mann-Whitney U tests, with P <.05 considered significant. RESULTS: In demographically similar groups, no differences were noted in times to onset and recovery of sensory and motor function, or complications; however, times to voiding and discharge were significantly longer in the bupivacaine group. Four and 2 patients in the bupivacaine and lidocaine groups, respectively, required intravenous analgesic supplementation. One patient in the lidocaine group experienced PSPS. CONCLUSIONS: Although prolongation to voiding and discharge was observed, intrathecal hyperbaric bupivacaine 3.75 mg with fentanyl 25 microg is a viable anesthetic for oocyte retrieval.

Adjuvants, Anesthesia↗
PubMedDate not supplied

Perioperative analgesia with subarachnoid sufentanil administration.

BACKGROUND AND OBJECTIVES: Thirty-seven ASA Physical Status I parturients undergoing elective cesarean delivery were evaluated to determine the effects of subarachnoid sufentanil administration. METHODS: This study was carried out in a randomized, double-blind fashion. All patients received 1.4 ml 0.75% bupivacaine with 8.25% dextrose following 10 micrograms, 15 micrograms, or 20 micrograms sufentanil, or 1 ml of normal saline containing no sufentanil. Onset and duration of sensory and motor anesthesia, duration of complete analgesia, duration of effective analgesia, and intraoperative parenteral opioid requirements were evaluated. Incidence of side effects such as respiratory depression, pruritus, nausea, and vomiting were evaluated. RESULTS: Duration of complete analgesia and duration of effective analgesia were prolonged significantly in all patient groups receiving sufentanil as compared to control groups receiving no narcotic. Pruritus was significantly increased in patient groups receiving subarachnoid sufentanil. Respiratory depression was not observed in any patient studied. One- and five-minute Apgar scores; umbilical, venous, and arterial blood gas results; and Early Neonatal Neurobehavioral Scale results were all within normal limits and were not significantly different among the groups.

Adult↗
PubMedDate not supplied

Regional anesthesia in women with chorioamnionitis.

BACKGROUND AND OBJECTIVES: Controversy regarding the use of regional anesthesia in parturients with chorioamnionitis stems from concern that, in bacteremic patients, anesthetic technique may result in infectious complications because of "seeding" of the epidural or subarachnoid space. This study attempts to evaluate the outcome of the parturient with chorioamnionitis based on anesthetic technique. METHODS: Data on chorioamnionitis was collected by review of all obstetric deliveries over a 1-year period with respect to type of anesthetic administered, blood culture results, antibiotic administration, and outcome. RESULTS: Three hundred nineteen women with chorioamnionitis were identified from a total of 10,047 deliveries over a 1-year period. Bacteremia was found in eight of these patients, three of whom received epidural anesthesia. None had received antibiotics before induction of anesthesia. No infectious complications related to anesthetic technique were found. Mean temperature and leukocyte counts were not significantly different between bacteremic and nonbacteremic groups. CONCLUSIONS: Although the total number of patients in this study is small, there is no evidence that regional anesthesia was detrimental to patients with chorioamnionitis. Factors such as leukocyte count and temperature elevation may not be predictive in identifying the bacteremic subgroup of patients.

Adult↗
PubMedDate not supplied

The antiemetic efficacy and safety of prophylactic metoclopramide for elective cesarean delivery during spinal anesthesia.

BACKGROUND AND OBJECTIVES: The efficacy and safety of intravenous metoclopramide administered prophylactically before elective cesarean delivery under spinal anesthesia was studied. METHODS: In a double-blind, randomized fashion, 42 ASA Physical Status I-II parturients at term were assigned to receive either 10-mg intravenous metoclopramide or an equal volume of normal saline before induction of spinal anesthesia. The occurrence of nausea and/or vomiting recorded throughout the perioperative period until the patient was admitted to the recovery room. Neonatal acid-base status and neurobehavioral exams were obtained. RESULTS: Patients in the group receiving metoclopramide had a significantly lower incidence of nausea and vomiting both before and after delivery than the control group (14% versus 81% overall). All neonatal acid-base values were within normal limits and there were no significant differences in neurobehavioral exam results between the two groups. CONCLUSIONS: Metoclopramide administered before induction of spinal anesthesia for cesarean delivery appears to significantly reduce both pre- and postdelivery emetic symptoms without apparent adverse effects on mother or neonate.

Adult↗
PubMedDate not supplied

Anesthesia for cesarean delivery in patients with herpes simplex virus type-2 infections.

Some concerns exist regarding the use of regional anesthesia for patients with active genital herpes simplex virus type-2 (HSV) infections undergoing cesarean delivery. Previous studies have reported the safe use of epidural anesthesia in these patients; there are no reports of the use of spinal anesthesia in this setting. We performed a 6-year retrospective survey of 169 patients delivered by cesarean delivery because of HSV infection. One hundred sixty-four of these patients had the diagnosis of secondary infection and five had the diagnosis of primary infection. Fifty-nine patients received general anesthesia, 75 received spinal anesthesia, and 35 received epidural anesthesia. One patient who was diagnosed with primary herpes and who received spinal anesthesia had a transient postpartum neurologic deficit; the etiology of this deficit was not clearly related to the anesthetic technique. No patients with secondary infection had septic or neurologic complications related to the anesthetic. Both spinal and epidural anesthesia appear to be safe alternatives for patients with secondary HSV infections undergoing cesarean delivery.

Anesthesia, Epidural↗