The effect of maternal position on fetal heart rate during epidural or intrathecal labor analgesia

OBJECTIVE

This study was designed to determine the relationship between maternal position and the incidence of prolonged decelerations after epidural bupivacaine or intrathecal sufentanil analgesia for labor.

STUDY DESIGN

Laboring, healthy, term parturient women, with reassuring fetal heart rate tracings, requesting either epidural (n = 145) or intrathecal (n = 160) analgesia were randomly assigned to lie either supine with measured 30-degree left uterine displacement (n = 136) or in the left lateral decubitus position (n = 145). Patients received either intrathecal sufentanil, 10 microg, or epidural 0.25% bupivacaine, 13 mL. An obstetrician, unaware of patient position or type of anesthesia, examined the fetal heart rate tracings.

RESULTS

No demographic differences were noted among the groups. Prolonged decelerations occurred with equal frequency after epidural bupivacaine and intrathecal sufentanil (3.9%). Prolonged decelerations were not related to maternal position. No emergency cesarean deliveries were performed as a result of prolonged decelerations. Prolonged decelerations correlated with the frequency of contractions before induction of analgesia (P < .05). Fewer fetal heart rate accelerations were noted after intrathecal sufentanil than after epidural bupivacaine (P < .005). More ephedrine was used after epidural bupivacaine (P < .001). Patients who received epidural analgesia in the left lateral position were more likely to have an asymmetric block (P < .05).

CONCLUSIONS

The risk of prolonged deceleration after epidural bupivacaine or intrathecal sufentanil labor analgesia is unrelated to maternal position or analgesic technique.

Venous embolization after deflation of lower extremity tourniquets

Massive pulmonary embolism has been reported to occur with the use of lower extremity tourniquets. We used transesophageal echocardiography to determine the incidence of venous embolism during lower extremity orthopedic surgery performed with a pneumatic tourniquet. The hemodynamic and respiratory consequences of all embolic events were assessed. Venous emboli were detected after tourniquet deflation in 8 of 30 procedures. The incidence of embolism was unrelated to the type of surgical procedure performed or the duration of tourniquet inflation. There were no significant differences in preoperative characteristics or postdeflation hemodynamic and respiratory responses between patients with and without emboli. Venous embolization is a relatively common event after tourniquet deflation. The clinical significance of these events remains to be determined.

Transdermal fentanyl for postoperative pain management in patients recovering from abdominal gynecologic surgery

The current placebo-controlled double-blinded study was undertaken to assess the safety and efficacy, as well as the potential clinical role, of the transdermal therapeutic system (TTS) of fentanyl delivery in the postoperative setting. TTS patches releasing 25 micrograms.h-1 or 50 micrograms.h-1 or placebo were applied to 95 women 1 h before abdominal gynecologic surgery during general anesthesia. Postoperatively, patients self-administered intravenous morphine as required using patient-controlled analgesia with a 1-mg incremental dose and a 6-min lockout interval. Each was assessed upon admission to the postanesthesia care unit and at intervals over the following 72 h with respect to vital signs, visual analogue scale pain and satisfaction scores, side effects, and cumulative morphine use. Data were analyzed using analysis of variance, Kruskal-Wallis, and chi-square. P less than 0.05 was considered significant. There were no demographic differences among groups. Beginning 32 h after TTS application, a statistically significant morphine-sparing effect was seen with the 50 micrograms.h-1 patch. There were no significant differences among groups with regard to visual analogue scale pain scores at rest, patient satisfaction, or the incidence of side effects; a significant reduction in pain upon movement was noted at 24 h in patients treated with TTS 50 micrograms.h-1. This finding constituted the only benefit noted with this form of analgesic therapy in the present investigation.

Influence of local anesthetic solution on postdural puncture headache

A total of 2,511 patients who received spinal anesthesia for cesarean delivery were observed for the development of postdural puncture headache (PDPH); 804 patients received a mixture of tetracaine and procaine, 942 received bupivacaine-glucose, and 765 received lidocaine-glucose. They were observed for the development of PDPH for a minimum of 72 h. PDPH occurred in 9.54% of patients who received lidocaine-glucose during the first 36 h compared with 7.64% of patients who received bupivacaine-glucose and 5.85% of patients who received tetracaine-procaine. The differences between all groups was statistically significant. No differences were found in the percentage of patients who ultimately required epidural blood patch for relief of symptoms after 36 h.

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)

The role of intrathecal opiates in the management of acute pain

This article reviews the literature and describes clinical methods of providing analgesia for acute pain using epidural and intrathecal (spinal) opiates. The mechanism of action of these drugs, their basic pharmacology and spinal pharmacodynamics, and useful drugs and dosages are presented. The side effects of these drugs when administered by injection and possible ways to diminish their incidence and severity are discussed. A clinical protocol for the dosage and selection of these drugs is included.

Epidural butorphanol-bupivacaine for analgesia during labor and delivery

A double-blind, randomized, dose-response study of a combination of 0.25% bupivacaine combined with 0, 1, 2, or 3 mg of butorphanol was studied in 40 laboring parturients. The optimal dose of butorphanol combined with 8.5 to 10 ml 0.25% bupivacaine was 2 mg; with 2 mg, the duration of analgesia was significantly greater and the time to onset of analgesia significantly shorter than when no butorphanol was added, and the amount of bupivacaine could be reduced 50%. Adverse fetal effects were not observed except that of a low amplitude sinusoidal fetal heart rate pattern with doses of 3 mg butorphanol. All neonatal observations were normal. It is concluded that epidural butorphanol can be a useful and safe adjunct to bupivacaine used for epidural analgesia during labor.

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.

Plasma and cerebrospinal fluid progesterone concentrations in pregnant and nonpregnant women

Pregnancy is associated with a wider dermatomal spread of local anesthetics after epidural and spinal anesthesia. This phenomenon also exists in the immediate postpartum period. The mechanism of this observation is unresolved. However, an increase in progesterone concentration in pregnancy has been implicated as one of the factors. Although plasma progesterone concentrations in humans have been well-documented, the cerebrospinal fluid (CSF) progesterone levels, which may also be important in this regard, have not been determined. Therefore, this study was undertaken to measure plasma and CSF progesterone in the nonpregnant, term parturient and in the immediate postpartum patient and also to determine the relationship between the CSF progesterone concentration and the intrathecal spread of lidocaine used for spinal anesthesia. The plasma progesterone concentrations in 12 nonpregnant, 21 term and eight postpartum patients were 2.3 +/- 61 (SEM) ng/ml, 122 +/- 8 ng/ml and 16 +/- 2.2 ng/ml, respectively. The CSF progesterone concentrations in term parturients (3 +/- 0.28 (SEM) ng/ml) and postpartum patients (1.03 +/- 0.16 ng/ml) were eight and three times greater than that of nonpregnant women (0.39 +/- 0.01 ng/ml). Significantly less lidocaine was needed (P less than 0.05) for comparable segmental levels of spinal anesthesia in term and postpartum patients than in nonpregnant individuals. These data suggest that high CSF, plasma progesterone concentrations, or both may augment the anesthetic spread of lidocaine.

Differential effects of ketamine stereoisomers on maze performance in the mouse

The authors studied effects of subanesthetic doses of the d- and l-ketamine stereoisomers on maze performance in mice to determine whether the stereoisomers differed in their ability to disrupt a stable cognitive behavior. Twenty-four Swiss-Webster (CFW) mice were trained to stability in a four-compartment modular maze, using water as a reward. Each compartment contained a central partition with a barrier at the distal end of one of the two passageways. A fixed barrier-sequence was employed. Elapsed time to traverse all four compartments and total number of errors (the number of times a wrong compartment was entered) were measured. A cohort design was employed with the following four groups: saline control, d-ketamine, l-ketamine, racemate. Two subanesthetic doses, 7.5 and 15 mg/kg of each form of the drug were given subcutaneously at five-day intervals. Both the d-isomer and the racemate significantly prolonged elapsed time at 15 mg/kg, the d-isomer having the greatest effect. The l-isomer did not alter elapsed time at either dose but appeared to increase spontaneous locomotor activity after injection. Relative to errors, at the 7.5 mg/kg dose there were no changes from control with any form of ketamine. However, at the 15 mg/kg dose, total errors significantly increased both with the racemate and the d-isomer. The performance decrements observed with the racemate appear to be attributable largely to the d-component.

Comparison of the maternal and neonatal effects of halothane, enflurane, and isoflurane for cesarean delivery

The maternal and neonatal effects of 50% O2-50% N2O alone and 50% O2-50% N2O combined with 0.5% halothane, 1.0% enflurane, or 0.75% isoflurane were studied in 42 healthy parturients undergoing general anesthesia for elective primary or repeat cesarean delivery at term. All patients received thiopental and succinylcholine for induction and were intubated and ventilated with a tidal volume of 10 ml/kg at a rate of 10 breaths/min. Two of 12 (17%) patients given O2-N2O alone had recall; none who received a potent inhalation agent had any recall. Blood loss was similar in all four groups. There were no significant differences between groups in induction-to-delivery and uterine incision-to-delivery intervals, the frequency of Apgar scores less than 7 at 1 and 5 min, maternal and fetal blood-gas tensions, acid-base balance, lactate values, and early neonatal neurobehavioral scores at 2-4 h. It is concluded that analgesic concentrations of halothane, enflurane, and isoflurane can be safely added to 50% O2-50% N2O to prevent maternal awareness during general anesthesia for cesarean delivery while maintaining normal maternal and neonatal conditions.

Dissociation of plasma and cerebrospinal fluid beta-endorphin-like immunoactivity levels during pregnancy and parturition

The association between central (cerebrospinal fluid [CSF]) and peripheral (plasma) levels of beta-endorphin-like immunoactivity (beta-ELI) in nonpregnant women (n = 8) and pregnant women (a) at 16 to 20 weeks of gestation (n = 6), (b) at term (n = 21), and (c) in labor (n = 15) was investigated. Umbilical arterial (n = 11) and venous (n = 11) samples were also obtained. In agreement with previous investigations, it was found that plasma levels of beta-ELI increased during labor (mean +/- SEM: nonpregnant women, 63.5 +/- 18.2; pregnant women at term, 64.0 +/- 12.2; women in labor, 110.8 +/- 30.3 pg/ml), and that levels of umbilical arterial plasma of beta-ELI exceeded those in umbilical venous plasma (132.5 +/- 34.0 versus 68.2 +/- 22.2). However, CSF levels of beta ELI did not change over the course of pregnancy or during labor (nonpregnant women, 36.5 +/- 15.8; pregnant women at 16 to 20 weeks of gestation, 60.1 +/- 10.3; pregnant women at term, 57.5 +/- 8.4; women in labor 48.5 +/- 8.3 pg/ml). This evidence that plasma and CSF levels of beta-ELI are dissociated during labor calls into question inferences regarding behavioral changes during parturition based on plasma beta-ELI measurements.

Acid-base status of diabetic mothers and their infants following spinal anesthesia for cesarean section

Acid-base status and Apgar scores were evaluated in 10 rigidly controlled insulin-dependent diabetic mothers and 10 healthy nondiabetic control women having spinal anesthesia for cesarean section. Dextrose-free intravenous solutions were used for volume expansion before induction of anesthesia, and hypotension was prevented in all cases by prompt treatment with ephedrine. There were no significant differences in the acid-base values between the diabetic and nondiabetic mothers and the infants of the diabetic and control group. Apgar scores were also similar in the two groups. If maternal diabetes is well controlled, if dextrose-containing solutions are not used for maternal intravascular volume expansion before delivery, and if maternal hypotension is avoided, spinal anesthesia can be used safely for diabetic mothers having cesarean section.

Hepatitis and operating-room personnel: an approach to diagnosis and management

Hepatitis represents a common problem in operating room (OR) personnel. The differential diagnosis is usually narrowed to viral hepatitis versus halothane-associated hepatitis. While specific immunologic technics are available to diagnose viral hepatitis, halothane hepatitis cannot presently be unequivocally diagnosed with available clinical, biochemical, immunologic, or pathologic technics. Suggestions for management of OR personnel with hepatitis can only be based on insufficient evidence at present. The authors have initiated a prospective study to help clarify this situation.