William Camann

A Comparison of Intrathecal, Epidural, and Intravenous Sufentanil for Labor Analgesia

A number of recent studies have suggested that the analgesic effects of highly lipid-soluble opioids are similar when these agents are administered either epidurally or intravenously. We sought to test whether the lipid-soluble opioid sufentanil was more effective when administered intrathecally than when administered epidurally or intravenously. Twenty-four women during active labor received sufentanil 10 micrograms either intrathecally (n = 9), epidurally (n = 8), or intravenously (n = 7), using a combined spinal-epidural technique. The sufentanil was administered alone, without concomitant local anesthetics. Analgesia was assessed using the visual analogue score as well as the time elapsed from the administration of study drug to the patients request for additional analgesia via the epidural catheter (bupivacaine 0.25%). The median duration of analgesia (median, interquartile range) was 84 (70-92) min in the intrathecal group, 30 (23-32) min in the epidural group, and 34 (17-30) min in the intravenous group (P < 0.001). The intrathecal group showed rapid and significant decrease in visual analogue scale scores, whereas visual analogue scale scores in the other two groups did not decrease and remained significantly elevated compared to those of the intrathecal group at all observation points. Side effects were limited to pruritus in 3 patients (2 moderate and 1 severe) in the intrathecal group. No patient developed post-dural puncture headache. We conclude that sufentanil 10 micrograms intrathecally provides rapid and effective analgesia of 1-2-h duration during labor. Epidural and intravenous use of this dose of sufentanil did not provide evidence of satisfactory analgesia.(ABSTRACT TRUNCATED AT 250 WORDS)

Effects of oral caffeine on postdural puncture headache : a double-blind, placebo-controlled trial

Forty postpartum patients with postdural puncture headache (PDPH) were randomly assigned to receive oral caffeine (300 mg) or a placebo. Intensity of headache, quantitated using a visual analogue pain scale (VAS), was assessed immediately before drug administration and 4 and 24 h later. Relief of PDPH measured as ΔVAS (initial VAS—VAS at 4 h) was significantly better in the caffeine than in the placebo group (P = 0.014). Six patients (30%) whose PDPH was relieved by caffeine at 4 h had recurrence of symptoms the following day. Our study demonstrates that caffeine administered orally provides relief, albeit if sometimes transient, from PDPH with minimal side effects.

The addition of bupivacaine to intrathecal sufentanil for labor analgesia

We designed a prospective, randomized, double-blind study to evaluate the efficacy of the combination of intrathecal sufentanil with a low dose of local anesthetic in an attempt to prolong analgesia in labor. Fifty-two patients received one of the following intrathecal study solutions: 2.5 mg of bupivacaine; 10 micro gram of sufentanil; or 2.5 mg of bupivacaine plus 10 micro gram of sufentanil. The mean duration of analgesia (min +/- SD) was significantly different among all three groups: 70 +/- 34 min for bupivacaine, 114 +/- 26 min for sufentanil, and 148 +/- 27 min for bupivacaine-sufentanil (P < 0.001). Visual analog scale (VAS) scores for pain were significantly higher in the bupivacaine group compared to both the sufentanil group and the bupivacaine-sufentanil group (P < 0.02), and were significantly higher in the sufentanil group compared to bupivacaine-sufentanil at 75 min postinjection and beyond (P < 0.02). Hypotension was not observed in the sufentanil group but occurred transiently in the other two groups (P = 0.09). There was no evidence of motor blockade, excessive somnolence, fetal heart rate (FHR) abnormalities, or postdural puncture headache (PDPH) in any of the patients. The addition of 2.5 mg of bupivacaine to 10 micro gram of intrathecal sufentanil significantly prolonged labor analgesia without adverse maternal or fetal effects. (Anesth Analg 1995;81:305-9)

Clinical Effects and Maternal and Fetal Plasma Concentrations of Epidural Ropivacaine Versus Bupivacaine for Cesarean Section

Background Ropivacaine is a new amide local anesthetic structurally similar to bupivacaine and mepivacaine. Previous studies showed that ropivacaine has a similar clinical effect as bupivacaine with regard to sensory anesthesia and slightly less motor blockade than bupivacaine. Ropivacaine appears to be less cardiotoxic and arrhythmogenic than bupivacaine. The clinical and pharmacokinetic effects of 0.5% ropivacaine (5 mg/ml) versus 0.5% bupivacaine (5 mg/ml) when used epidurally for elective cesarean section were investigated. Methods Using a randomized, double-blind study design, 60 ASA physical status 1 or 2 term parturients presenting for elective cesarean section received either 0.5% bupivacaine (150 mg) or 0.5% ropivacaine (150 mg) epidurally in appropriate fractionated doses over a 10-min period. Onset, duration, and regression of sensory and motor blockade were noted until complete resolution was observed. Quality of intraoperative anesthesia and abdominal wall muscle relaxation were noted. Maternal plasma concentrations of local anesthetic were determined before anesthetic administration and 5, 10, 20, 30, and 60 min and 2, 3, 6, 8, 12, and 24 h after drug injection in 20 subjects. Umbilical cord blood was obtained at time of delivery for acid-base values and determination of the free and total plasma concentration of local anesthetic. Neonates also were examined for neurobehavioral assessments by Scanlons and Neurologic and Adaptive Capacity Scores at 2 and 24 h after delivery. Results All patients received satisfactory anesthesia for operation. The onset, duration, and regression of sensory blockade were similar for both groups. Onset of degree 1 and 2 motor blockade was faster, and duration of degree 1 motor block was longer in the group receiving bupivacaine. Hemodynamic sequelae were similar between groups. All neonates had 5-min Apgar scores of 7 or greater and normal acid-base values and neurobehavioral assessments. Pharmacokinetic analysis showed that the Cmax was similar for both drugs (1.3 plus/minus 0.09 for ropivacaine and 1.1 plus/minus 0.09 micro gram/ml for bupivacaine). The T1/2 of the terminal decline in plasma concentration was shorter for ropivacaine versus bupivacaine (5.2 plus/minus 0.60 versus 10.9 plus/minus 1.08 h, respectively; P < 0.01). The free (i.e., unbound) concentrations of ropivacaine were approximately twice those of bupivacaine in both maternal and neonatal blood at the time of delivery. The ratio of umbilical vein to maternal vein concentration of unbound drug was 0.72 for ropivacaine and 0.69 for bupivacaine. Conclusions Ropivacaine, 0.5%, epidurally provided satisfactory and similar sensory anesthesia compared to 0.5% bupivacaine for elective cesarean section. The Cmax was similar for both drugs, although the terminal half-life of ropivacaine was significantly shorter, and the blood concentrations of free ropivacaine were significantly greater than that for bupivacaine. These values were less than concentrations shown to be toxic in animals.

Nocebo-induced hyperalgesia during local anesthetic injection.

Common practice during local anesthetic injection is to warn the patient using words such as: “You will feel a big bee sting; this is the worst part.” Our hypothesis was that using gentler words for administration of the local anesthetic improves pain perception and patient comfort. One hundred forty healthy women at term gestation requesting neuraxial analgesia were randomized to either a “placebo” (“We are going to give you a local anesthetic that will numb the area and you will be comfortable during the procedure”) or “nocebo” (“You are going to feel a big bee sting; this is the worst part of the procedure”) group. Pain was assessed immediately after the local anesthetic skin injection using verbal analog scale scores of 0 to 10. Median verbal analog scale pain scores were lower when reassuring words were used compared with the harsher nocebo words (3 [2–4] vs 5 [3–6]; P < 0.001). Our data suggest that using gentler, more reassuring words improves the subjective experience during invasive procedures.

Intrathecal sufentanil for labor analgesia. Effects of added epinephrine

Background:Intrathecal sufentanil has been found to provide profound analgesia during labor. Epinephrine, when added to various local anesthetic agents or opioids, may modify the analgesic profile and incidence of side effects. The authors sought to determine the effect of adding 0.2 mg epinephrine to 10 µg sufentanil when administered for analgesia during labor. Methods:Forty women during active labor received 10 µg intrathecal sufentanil either with (n = 20) or without (n = 20) 0.2 mg epinephrine in a randomized, blinded fashion. A combined spinal-epidural technique was used in which a 25-G Whitacre spinal needle was passed through a standard 17-G epidural needle. After injection of the study drug, an epidural catheter was passed, but no local anesthetics were given. Analgesia was quantitated using visual analog scores, as well as time elapsed until first request for additional analgesia via the epidural catheter (0.25% bupivacaine). The incidence and severity of pruritus, nausea, and somnolence were assessed. Results:The duration (median, range) of analgesia was 90 (40-310) min in the plain sufentanil group (SUF) and 90 (45- 230) min in the sufentanil-epinephrine (SUF-EPI) group (P = NS). The onset of analgesia was rapid (within 5 min) in both groups and visual analog scores did not differ at any observation point between groups. The incidence of pruritus was 80%16/20) in the SUF group, and 45% (9/20) in the SUF-EPI group (P = 0.05). Four patients in the SUF group rated the pruritus as severe versus none in the SUF-EPI groups (P = 0.05). Seven patients (35%) in the SUF-EPI group experienced nausea, versus none in the SUF group (P = 0.004). No patient developed hypotension, motor blockade, fetal heart rate abnormalities, excessive sedation, or postdural puncture headache. Conclusions:Intrathecal sufentanil 10 µg, both with and without epinephrine, provided rapid-onset, albeit short-duration, analgesia during labor. Epinephrine did not prolong the duration of intrathecal sufentanil analgesia. The addition of epinephrine increased the incidence of nausea and decreased the incidence and severity of pruritus.

Clinical effects and maternal and fetal plasma concentrations of 0.5% epidural levobupivacaine versus bupivacaine for cesarean delivery.

BACKGROUND Bupivacaine exists as a mixture of two enantiomers, levobupivacaine and dexbupivacaine. Data suggest that levobupivacaine has equal local anesthetic potency, with reduced potential for central nervous system and cardiovascular toxicity. The present study compares the efficacy of 0.5% levobupivacaine with 0.5% bupivacaine for epidural anesthesia in parturients undergoing elective cesarean delivery. METHODS Sixty healthy obstetric patients undergoing elective cesarean delivery with epidural anesthesia completed the study. Patients were randomized to receive 30 ml of either 0.5% levobupivacaine or 0.5% bupivacaine in a double-blind fashion. The efficacy endpoint measures included onset, offset, and quality of anesthesia. Neonatal blood gas analyses, Apgar score determinations, and neurobehavioral examinations were performed. Venous samples for pharmacokinetic studies and serial electrocardiograms were obtained in 10 patients in each group. RESULTS Levels of sensory block, motor block, muscle relaxation, and overall quality of anesthesia did not differ between groups. The frequency of hypotension was 84.4% in the levobupivacaine group and 100% for the bupivacaine group (P < or = 0.053). No significant difference in observed maximum concentration of drug after dosing or area under the plasma drug concentration versus time curve were seen. The maximum concentrations were 1.017 and 1.053 microg/ml, and the areas were 4.082 and 3.765 h(microg/ml) for the levobupivacaine and bupivacaine groups, respectively. Umbilical vein-to-maternal vein ratios were 0.303 for the levobupivacaine group and 0.254 for the bupivacaine group. CONCLUSIONS The use of epidural 0.5% levobupivacaine for cesarean delivery results in equally efficacious anesthesia compared with 0.5% bupivacaine. Pharmacokinetic parameters were similar in the two groups.

Herbal medicine use in parturients

Alternative medicine use has increased dramatically over the last decade. Recently a 22% incidence of herbal medicine use in presurgical patients was reported. Of concern is the potential for these medications to cause adverse drug-herb interactions or other effects such as bleeding complications. We sought to determine the prevalence and pattern of use of herbal remedies in parturients. A one-page questionnaire examining the use of all prescription and nonprescription medications, including herbal remedies, was sent to parturients expected to deliver within 20 wk who had preregistered with the hospital’s admissions office. Sixty-one percent of the parturients responded to the survey, with 7.1% of parturients reporting the use of herbal remedies. Only 14.6% of users considered them to be medications. Parturients in the 41–50 yr age bracket (5.6% of parturients) were the most likely to use herbal remedies (17.1% rate of use in this age group). Many parturients who took herbal remedies (46%) did so on the recommendation of their health care provider.

General anesthesia for cesarean section at a tertiary care hospital 1990–1995: indications and implications

Complications of general anesthesia for cesarean section remain the leading cause of anesthesia-related maternal mortality. General anesthesia, however, is becoming less popular for obstetric anesthesia, and thus fewer cesarean sections are conducted using this technique. As the number of general anesthesia cases decrease, the number of difficult intubations witnessed and managed by residents decreases. In addition, patients who undergo general anesthesia may have co-morbidities which, while not contraindicating regional anesthesia, may increase the risk of providing anesthesia. We reviewed the medical records of 6 calendar years (1990-1995) at our busy tertiary center, to determine patient demographics, indications for cesarean section, indications for general anesthesia, time of day, and complications related to airway management. From 1990 through 1995, cesarean sections under general anesthesia decreased from 7.2% to 3.6% (P=0.0001), however, they were performed on parturients with more maternal diseases (17.2% to 35.8%; P=0.0034). Although the incidence of difficult intubations in those years ranged from 16.3% to 1.3%, only one failed intubation with resultant maternal mortality occurred. Few residency programs offer instruction on the difficult airway in the parturient population. Organized airway management programs specifically for the obstetric population may assist efforts to decrease the morbidity and mortality associated with the provision of general anesthesia for cesarean section.

Intrathecal ropivacaine for labor analgesia: a comparison with bupivacaine.

Ropivacaine has less potential for central nervous system and cardiovascular toxicity than bupivacaine; in pregnant patients and volunteers, it produces less motor block in equianalgesic doses than bupivacaine.We compared two doses of intrathecal ropivacaine combined with sufentanil with a standard dose of intrathecal bupivacaine plus sufentanil for labor analgesia using a combined spinal-epidural (CSE) technique. In a prospective, randomized, double-blind fashion, 48 patients requesting labor analgesia received either 2.5 mg of intrathecal bupivacaine plus sufentanil 10 [micro sign]g (B), 2 mg of intrathecal ropivacaine plus sufentanil 10 [micro sign]g (R2), or 4 mg of intrathecal ropivacaine plus sufentanil 10 [micro sign]g (R4). Duration of analgesia and side effects, such as motor block, pruritus, hypotension, ephedrine requirements and fetal bradycardia, were recorded. Duration of analgesia (mean +/- SD) was 79 +/- 30 min for R2, 98 +/- 19 min for R4, and 92 +/- 38 min for B (P = not significant). No differences in motor block or side effects were detected among the groups. We conclude that ropivacaine, when combined with sufentanil, is effective for providing CSE labor analgesia and offers no advantage over bupivacaine in the studied doses. Implications: In this study, we compared a standard dose of intrathecal bupivacaine with sufentanil for combined spinal epidural analgesia with two doses of the new local anesthetic ropivacaine. Both local anesthetics provided similar labor analgesia duration with equivalent side effect profiles in the doses studied. (Anesth Analg 1998;87:624-7)