J. D. Vertommen

The effects of the addition of sufentanil to 0.125% bupivacaine on the quality of analgesia during labor and on the incidence of instrumental deliveries.

In a double-blinded, randomized, prospective multi-center study of 695 women, we investigated whether epidural injection of sufentanil added to 0.125% bupivacaine with epinephrine (1:800,000) reduces the total amount of local anesthetic required, resulting in less motor blockade and reduced incidence of instrumental deliveries, and improves the quality of analgesia provided by this low concentration of local anesthetic without jeopardizing the safety of the baby. In addition, other potential benefits of sufentanil (such as decrease in the incidence of shivering) and side effects were examined. It was found that adding incremental doses of 10 micrograms sufentanil up to a maximum of 30 micrograms reduced the incidence of instrumental deliveries from 36 to 24% (P less than 0.01) and significantly improved quality and duration of analgesia without depressing the neurobehavioral status of the baby. No other benefits from adding sufentanil were found. The only side effect that occurred more frequently after sufentanil was pruritus. We conclude that epidural injection of 10-30 micrograms sufentanil added to 0.125% bupivacaine with epinephrine (1:800,000) improved the quality of analgesia during labor and reduced the incidence of instrumental deliveries without jeopardizing the safety of the baby.

Maternal and neonatal effects of adding epidural sufentanil to 0.5% bupivacaine for cesarean delivery

STUDY OBJECTIVE To determine the maternal and fetal effects of the addition of epidural sufentanil to 0.5% bupivacaine for cesarean delivery. DESIGN Randomized, double-blind, prospective study. SETTING University Hospitals, Katholieke Universiteit Leuven, Leuven, Belgium. PATIENTS Sixty women at term scheduled for elective cesarean section, all of whom had elected epidural anesthesia. INTERVENTIONS The 60 women were divided into three groups of 20, with each group receiving a different 1 ml study solution: saline (control) or sufentanil 20 micrograms or sufentanil 30 micrograms added to 0.5% bupivacaine and epinephrine (1:200,000). MEASUREMENTS AND MAIN RESULTS In the mother, the quality of anesthesia, the duration of postoperative analgesia, the volume of anesthetic, and the frequency of side effects were examined. The neonates were evaluated at 5 and 10 minutes after birth by Apgar scores and between 60 and 120 minutes after birth by both the screening test developed by Prechtl and the Neurological and Adaptive Capacity Scoring System. Immediately after delivery, maternal and umbilical vein blood were drawn and assayed for sufentanil levels. Adding sufentanil significantly improved the quality of anesthesia without depressing the neurobehavioral status of the baby. CONCLUSION The epidural injection of sufentanil added to 0.5% bupivacaine with epinephrine improved the quality of anesthesia during elective cesarean section without jeopardizing the safety of the baby.

Shape and surface smoothness of pellets made in a rotary processor

Abstract The shape and surface smoothness of pellets made in a rotary processor by the wet granulation technique has been studied. Optical microscopy combined with image analysis was used to determine three shape parameters (circularity, roundness and elongation) and the fractal dimension, which is a characteristic for the surface smoothness of the pellets. This study reveals that pellets made in a rotary processor by the wet granulation technique are more variable in terms of their sphericity than in terms of their elongation. In order to obtain very spherical pellets, spheronization should go on for a long time with sufficient intensity. Furthermore, the spheronization enhancing properties of microcrystalline cellulose—thanks to its plastic properties when wetted—are confirmed. The fractal dimensions of the surface are close to 2, indicating that the pellets are characterized by a rather smooth surface. Nevertheless, small but significant differences in surface smoothness can be detected using this fractal approach. From the experiments performed in this study, it can be concluded that using the wet granulation technique in the rotary processor under the appropriate conditions, it is possible to produce excellent pellets in terms of sphericity and surface smoothness.

Labor pain relief using bupivacaine and sufentanil: Patient controlled epidural analgesia versus intermittent injections

OBJECTIVES To determine whether the use of patient-controlled epidural analgesia (PCEA) versus intermittent injections (CIT) resulted in local anesthetic dose reduction. STUDY DESIGN PCEA and CIT using a mixture of 0.125% bupivacaine with sufentanil 1 or 0.75 microgram/ml were compared in 60 and 195 parturients, respectively. Assessments included pain scores, local anesthetic consumption, degree of motor blockade, type of delivery and neonatal outcome. Statistical analysis was done using Students t test and Chi-squares. RESULTS PCEA and CIT provided effective analgesia during labor and delivery. A higher dose of opioid significantly reduced the use of local anesthetic solution in PCEA-patients. There was no difference in motor blockade, type of delivery and neonatal outcome. CONCLUSION Patient-controlled epidural analgesia is an effective, safe and acceptable alternative to conventional intermittent epidural injections for pain relief during labor and delivery.

Hydroxyethyl starch versus lactated Ringer's solution in the chronic maternal-fetal sheep preparation: a pharmacodynamic and pharmacokinetic study.

Administration of fluids intravenously prior to spinal and epidural analgesia in obstetrics is required to prevent maternal hypotension and fetal hypoxia.A colloid solution, such as hydroxyethyl starch (HES), might be preferable considering the capacity to stay intravascularly for a longer period. In this study the placental transfer of HES and the hemodynamic effects after infusion were investigated using a chronic maternal-fetal sheep preparation. Either 500 mL HES 10% or 750 mL lactated Ringers solution (RL) was infused intravenously into the ewe over 30 min. Fetal and maternal blood were assayed for HES, blood gases, and acid-base status before and at regular intervals after infusion. Maternal and fetal cardiovascular variables were recorded continuously for 90 min. After HES infusion, maternal HES levels peaked at 30 min ranging from 6.9 mg/mL to 12.1 mg/mL and declined at 24 h to levels between 0.3 mg/mL and 2.8 mg/mL. Mean fetal HES concentrations remained below 0.3 mg/mL. Infusion of HES decreased hemoglobin (Hb) and plasma viscosity (PV) in the mother. Infusion of RL decreased Hb, but did not change PV. Infusion of HES significantly increased uterine blood flow (UBF), cardiac output (CO), total oxygen-delivery capacity, and uterine artery oxygen delivery. In contrast, infusion of RL did not significantly change these variables. Infusion of HES increases UBF, CO, and uterine and total oxygen-carrying capacity in the pregnant ewe. No significant transplacental transfer of HES was shown. (Anesth Analg 1995;80:949-54)

Hydralazine Does Not Restore Uterine Blood Flow during Cocaine-induced Hypertension in the Pregnant Ewe

Cocaine abuse is widespread, and its use by the parturient has potential significant adverse effects in both the mother and the newborn. This study was undertaken in gravid ewes to determine the effects of treatment of cocaine-induced hypertension with hydralazine (Apresoline) on the maternal and fetal cardiovascular systems, catecholamine response, blood gas and acid-base status, and uterine blood flow (UBF). Twenty-one experiments were performed in 15 chronically instrumented ewes near term gestation. After a 30-min control period, cocaine was given intravenously to all ewes for 55 min to induce and maintain increased maternal mean arterial pressure (MMAP) and reduced UBF. The sheep were randomly assigned to receive either cocaine alone (n = 11, control group) or hydralazine (n = 10, treatment group), starting 15 min after the cocaine administration. Both drugs were discontinued 55 min after the start of the cocaine administration, followed by a 35-min recovery period. In the control group, cocaine administration resulted in a 31 +/- 13% (SD) increase in MMAP (P less than 0.05) and a 26 +/- 21% reduction in UBF (P less than 0.05). In the treatment group, the initial cocaine administration resulted in a similar increase in MMAP and decrease in UBF. Hydralazine therapy restored MMAP toward baseline after 20 min of administration, but UBF remained reduced (37 +/- 17%) throughout therapy (P less than 0.05) and recovery (18 +/- 13%) (P less than 0.05). The maternal heart rate increased maximally by 121 +/- 33% (P less than 0.05) after the administration of hydralazine, compared with a 14 +/- 21% increase (P less than 0.05) in the control group.(ABSTRACT TRUNCATED AT 250 WORDS)

Hemodynamic effects of intravenous isoproterenol versus epinephrine in the chronic maternal-fetal sheep preparation

Isoproterenol 5 micro gram may be an effective marker of accidental intravascular injection in women in labor; however, before isoproterenol can be incorporated in routinely used epidural test doses, the safety and usefulness should be determined in an animal model.This study was designed to examine the hemodynamic effects of isoproterenol in comparison with epinephrine in the pregnant ewe. Five doses of isoproterenol were tested and compared with two doses of epinephrine in a randomized cross-over fashion. After administration of isoproterenol there was a small decrease of uterine blood flow (UBF) and maternal mean arterial pressure (MMAP), which both almost immediately returned to baseline. When epinephrine was used a more pronounced and more prolonged decrease of UBF occurred. Increasing doses of isoproterenol resulted in dose-dependent increases in maternal heart rate (MHR), while with epinephrine this was not the case. A significant increase in the cardiac output was seen after isoproterenol. Neither isoproterenol nor epinephrine affected fetal heart rate (FHR), fetal mean arterial pressure (FMAP), amniotic fluid pressure (Amn-pr), blood gases, or acid base status in the mother and the fetus. Provided that neurotoxic effects are absent, isoproterenol might be a better alternative than epinephrine as a test dose for possible intravenous placement of an epidural catheter in pregnant women. (Anesth Analg 1996;82:1023-6)

Internal and external structure of pellets made in a rotary processor

The internal and external structure of pellets made in a rotary processor by the wet granulation technique was studied using the following techniques: helium pycnometry to determine the true density, krypton adsorption to determine the specific surface area, mercury porosimetry, and scanning electron microscopy. The results of the true density measurements, specific surface area determinations and mercury porosimetry led to the hypothesis that the pellets were open porous sponge structures. Mercury mainly intruded in the macropore range (pores with a radius between 7 and 0.05 μm). The pores and cavities were partially closed as spheronization went on leading to air pockets in the pellets. Scanning electron microscopic pictures provided visual support for the hypothesis that the pellets had a porous surface and that the pellets contained cavities, which could be closed resulting in the formation of air pockets. To reduce the pore volume and smooth the surface, the rotor speed should be high and the spheronization time should be long. The plastic properties of wetted microcrystalline cellulose promoted the smoothing of the surface.

The Effects of Intravenous and Epidural Sufentanil in the Chronic Maternal-Fetal Sheep Preparation

This study examines the placental transfer and hemodynamic and acid-base changes after intravenous (IV) and epidural administration of sufentanil in the chronically instrumented maternal-fetal sheep preparation. A dose of 50 micro gram sufentanil was injected either IV or epidurally into seven ewes. Neither IV nor epidural injection of sufentanil affected maternal mean arterial pressure (MMAP), uterine blood flow (UBF), maternal heart rate (MHR), fetal mean arterial pressure (FMAP), fetal heart rate (FHR), or blood gases and acid-base status in mother and fetus, After IV administration, a peak sufentanil level of 1.28 ng/mL +/- 0.285 (SD) was detected in maternal plasma. A peak plasma level of 0.037 ng/mL +/- 0.041 (SD) was attained in the fetus. A constant maternal-fetal concentration ratio of 5.5 from 15-60 min after the IV injection was found. After epidural injection a mean peak plasma level of 0.059 ng/mL +/- 0.042 (SD) was reached in the mother 25 min after injection. Sufentanil levels were undetectable in fetal plasma after epidural injection into the mother. Because placental transfer of sufentanil is small, the maternal and fetal cardiovascular and acid-base effects are minimal in the pregnant ewe. (Anesth Analg 1995;80:71-5)

The effects of adding isoproterenol to 0.125% bupivacaine on the quality and duration of epidural analgesia in laboring parturients.

This study was conducted to determine the effects of adding isoproterenol to epidural bupivacaine and sufentanil on the quality and duration of analgesia during labor.In a double blind, randomized study, 80 women were divided into two groups, receiving three doses of 0.125% bupivacaine with 7.5 [micro sign]g of sufentanil and either 12.5 [micro sign]g of epinephrine (EPI group) or 5 [micro sign]g of isoproterenol (ISO group). Contraction pain was measured using a 100-mm visual analog scale (VAS) before epidural analgesia, at 5-min intervals for 15 min after each epidural injection, and hourly thereafter. Overall, no significant differences were observed in VAS scores between the groups. However, in the ISO group, VAS scores at 10 and 15 min after the first and second administration were significantly lower than those in the EPI group. Analgesia after each administration lasted significantly longer in patients who received epinephrine. Because of the limited duration of analgesia in the ISO group, more patients in this group received a fourth epidural administration of 0.125% bupivacaine with epinephrine 1:800,000. In conclusion, the addition of isoproterenol to bupivacaine and sufentanil induces a faster onset of analgesia and reduces the duration of analgesia compared with bupivacaine with sufentanil and epinephrine. Therefore, it is preferable to use isoproterenol only once, as a test dose, after the placement of the epidural catheter. Implications: We analyzed the quality and duration of analgesia in laboring women after they received bupivacaine and sufentanil combined with isoproterenol or epinephrine epidurally. We found that the addition of isoproterenol to bupivacaine and sufentanil induces a faster onset of analgesia and reduces the duration of analgesia. (Anesth Analg 1998;86:749-52)