Valerie A. Arkoosh

Complications of labor analgesia : epidural versus combined spinal epidural techniques

Both epidural and combined spinal epidural (CSE) analgesia can provide maternal pain relief during labor. Currently, there are few data comparing the risks and complications of these two techniques. We recorded the incidence and severity of anesthetic-related complications in 1022 laboring parturients. Ninety-eight women opted for either no or parenteral analgesia, 388 chose epidural, and 536 requested CSE analgesia. Women choosing CSE analgesia most often received an intrathecal injection of sufentanil 10 micrograms at the time of epidural catheter insertion. The epidural catheters were then dosed as needed as the intrathecal analgesia waned. Women who received CSE analgesia were more likely to itch (41.4% vs 1.3%) or complain of nausea (2.4% vs 1.0%) or vomiting (3.2% vs 1.0%) than those receiving solely epidural analgesia. Patients who requested only epidural analgesia were more likely to suffer an unintended dural puncture (4.2% vs 1.7%). Fewer than 10% developed hypotension with either technique. The risk of headache was the same with both anesthetics (4%-10%) and did not differ from the incidence of headache in women not receiving neuraxial analgesia (10%-14%). Six patients required epidural blood patch for moderate to severe postural headache. Four of these women suffered a dural puncture with the 18-gauge Hustead epidural needle. The other two women had reportedly uncomplicated epidural and CSE analgesia. These data suggest either neuraxial analgesic technique can safely relieve the pain of labor. CSE analgesia is a safe alternative to epidural analgesia for labor and delivery.

Comparison among intrathecal fentanyl, meperidine, and sufentanil for labor analgesia

This study compared the analgesic efficacy of intermittent injections of intrathecal fentanyl (10 micrograms), meperidine (10 mg), or sufentanil (5 micrograms) administered to 65 parturients during the first stage of labor. The groups did not differ in onset or duration of effective analgesia. The meperidine group, however, had significantly lower pain scores once cervical dilation progressed beyond 6 cm. Side effects included mild pruritus and nausea. After intrathecal drug injection, variable decelerations of the fetal heart rate increased in the fentanyl and meperidine groups. All neonates had a 5-min Apgar score of 7 or more. We conclude that intermittent intrathecal injections of fentanyl, meperidine, or sufentanil can provide adequate first-stage labor analgesia. Meperidine appears to provide more reliable analgesia as the first stage of labor progresses.

Using heart rate variability to stratify risk of obstetric patients undergoing spinal anesthesia.

In this study, we evaluated whether point correlation dimension (PD2), a measure of heart rate variability, can predict hypotension accompanying spinal anesthesia for cesarean delivery. After the administration of spinal anesthesia with bupivacaine, hypotension was defined as systolic blood pressure ≤75% of baseline within 20 min of intrathecal injection. Using the median prespinal PD2 (3.90) to form 2 groups, LO and HI, all 11 hypotensive patients were in the LO group, and all 11 patients without hypotension were in the HI group. Baseline heart rate in the LO group was 95 bpm (10.2 sd), versus 81 bpm (9.6 sd) in the HI group. PD2 shows promise as a predictor of hypotension in pregnant women receiving spinal anesthesia.

Intrathecal sufentanil labor analgesia: the effects of adding morphine or epinephrine.

Intrathecal opioids can provide labor analgesia. We attempted to prolong the duration of intrathecal sufentanil analgesia by adding epinephrine or morphine. Forty-one healthy, term nulliparae with cervical dilation < 5 cm participated in this double-blind, randomized protocol. Using a combined spinal and epidural technique, we gave intrathecal injections of either sufentanil 10 micrograms, sufentanil 10 micrograms plus epinephrine 200 micrograms, or sufentanil 10 micrograms plus morphine 250 micrograms. At baseline and every 5 min for 30 min thereafter, we recorded arterial blood pressure and asked the patients to rate their pain, nausea, and pruritus on visual analog scales. The women continued to rate these variables every 30 min until they requested additional analgesia. They then received 10 mL of 0.25% bupivacaine via the epidural catheter, and rated the above variables every 30 min until they requested additional epidural drug injection. Both morphine and epinephrine prolonged the duration of sufentanil analgesia. Only morphine prolonged analgesia after the first dose of epidural bupivacaine. However, because women in the morphine group experienced significantly more side effects throughout the study period, we do not recommend intrathecal morphine for labor analgesia.

Intrathecal Sufentanil Dose Response in Nulliparous Patients

Background Intrathecal sufentanil provides effective analgesia during the first stage of labor. A range of doses has been reported to provide adequate pain relief. This study determined the dose of intrathecal sufentanil that produced acceptable pain relief in 50% of nulliparous patients (ED50) who requested labor analgesia. Methods With institutional review board approval, 50 nulliparous patients requesting spinal opioid labor analgesia were enrolled into this prospective, randomized, double‐blinded study. Each patient was in spontaneous labor at <5 cm cervical dilation. Patients received one of the following doses of intrathecal sufentanil: 1, 2, 3, 5, or 10 [micro sign]g in 3 ml preservative‐free saline (n = 10 for each dose). Pain, pain relief, hemodynamic, respiratory, and side effect data were collected at times 0, 2, 5, 10, 15, 20, 25, and 30 min. Probit analysis of the number of patients in each group who requested additional pain medicine at 30 min was used to determine the ED50. Results The groups were demographically similar. The ED50 of intrathecal sufentanil was 1.8 [micro sign]g (SE, 0.6 [micro sign]g; 95% CI, 2.96 to 0.54 [micro sign]g). The incidence of side effects was similar among the groups. Conclusions This is the first study to determine the ED50 of intrathecal sufentanil in spontaneously laboring nulliparous patients. As dose‐response curves are determined for other labor analgesics, future studies can compare equianalgesic doses or dose combinations.

A Randomized, Double-masked, Multicenter Comparison of the Safety of Continuous Intrathecal Labor Analgesia Using a 28-Gauge Catheter versus Continuous Epidural Labor Analgesia

Background:Continuous intrathecal labor analgesia produces rapid analgesia or anesthesia and allows substantial flexibility in medication choice. The US Food and Drug Administration, in 1992, removed intrathecal microcatheters (27–32 gauge) from clinical use after reports of neurologic injury in nonobstetric patients. This study examined the safety and efficacy of a 28-gauge intrathecal catheter for labor analgesia in a prospective, randomized, multicenter trial. Methods:Laboring patients were randomly assigned to continuous intrathecal analgesia with a 28-gauge catheter (n = 329) or continuous epidural analgesia with a 20-gauge catheter (n = 100), using bupivacaine and sufentanil. The primary outcome was the incidence of neurologic complications, as determined by masked neurologic examinations at 24 and 48 h postpartum, plus telephone follow-up at 7–10 and 30 days after delivery. The secondary outcomes included adequacy of labor analgesia, maternal satisfaction, and neonatal status. Results:No patient had a permanent neurologic change. The continuous intrathecal analgesia patients had better early analgesia, less motor blockade, more pruritus, and higher maternal satisfaction with pain relief at 24 h postpartum. The intrathecal catheter was significantly more difficult to remove. There were no significant differences between the two groups in neonatal status, post–dural puncture headache, hemodynamic stability, or obstetric outcomes. Conclusions:Providing intrathecal labor analgesia with sufentanil and bupivacaine via a 28-gauge catheter has an incidence of neurologic complication less than 1%, and produces better initial pain relief and higher maternal satisfaction, but is associated with more technical difficulties and catheter failures compared with epidural analgesia.

The dermatomal spread of epidural bupivacaine with and without prior intrathecal sufentanil.

Clinicians often use a technique combining intrathecal sufentanil and epidural bupivacaine to provide labor analgesia.This study determines the effect of 27- or 24-gauge dural puncture and intrathecal sufentanil 10 micro gram on the dermatomal spread of epidural bupivacaine. Healthy laboring women received no dural puncture (n = 77) (no puncture group [NPG]) or dural puncture with a 27-gauge Whitacre needle (n = 33) or a 24-gauge Sprotte needle (n = 37) and intrathecal sufentanil 10 micro gram (dural puncture group [DPG]) before epidural injection of 13 mL bupivacaine 0.25%. More dermatomes were anesthetized in the DPG, 16.6 +/- 7.5 vs 13.6 +/- 6.6 in the NPG (P < 0.02). More patients in the DPG had sensory blockade T-4 or higher (17 of 70 DPG patients vs 8 of 77 NPG patients; P < 0.05). No patient in either group showed clinical evidence of respiratory compromise. In conclusion, epidural bupivacaine anesthetized more dermatomes when administered 104 +/- 42 min after dural puncture and intrathecal sufentanil 10 micro gram than when given without prior dural puncture and intrathecal injection. (Anesth Analg 1996;83:526-9)

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.

Baricity, Needle Direction, and Intrathecal Sufentanil Labor Analgesia

Background Intrathecal sufentanil relieves labor pain but centrally mediated side effects are common. Preventing rostral spread of intrathecal sufentanil should limit these side effects. Both direction of the lateral opening of a pencil‐point needle and drug baricity modify the spread of intrathecal local anesthetics. This randomized, prospective, double‐blind study examines the effects of these variables on intrathecal sufentanil labor analgesia. Methods Forty laboring, full‐term parturients, whose cervixes were dilated less than 5 cm and who requested analgesia for labor were enrolled. Combined spinal epidural analgesia was induced in patients in the sitting position. They were allocated to receive 10 micro gram intrathecal sufentanil diluted with either normal saline or dextrose with the aperture of the pencil‐point needle directed cephalad or caudad during drug injection. Thus there were four groups of ten patients: dextrose up, dextrose down, saline up, and saline down. Sufentanil was diluted with normal saline to a concentration of 10 micro gram/ml. The study drug was made by mixing 1 ml sufentanil solution with either 1 ml 10% dextrose or 1 ml normal saline. Visual analog scores for pain, pruritus, nausea, and pain relief were recorded before and 5, 10, 15, and 30 min after drug injection. Results Baricity, but not needle orientation, influenced pain relief and pruritus. Sufentanil in dextrose produced less itching but also less analgesia. Nine of 20 women in the dextrose groups compared with 1 of 20 in the saline groups requested additional analgesia by 30 min. Conclusions Little or no labor analgesia developed for patients receiving sufentanil with dextrose. A supraspinal action may contribute to intrathecal sufentanils analgesic efficacy.

The Influence of Epidural Needle Bevel Orientation on Spread of Sensory Blockade in the Laboring Parturient

Both asymmetrical sensory blockade and dural puncture are undesirable outcomes of epidural analgesia.Identifying the epidural space with the needle bevel oriented parallel to the longitudinal axis of the patients back limits the risk of headache in the event of dural puncture. However, rotating the bevel to direct a catheter cephalad may risk dural puncture. We prospectively studied the effects of needle rotation on the success of labor epidural analgesia and on the incidence of dural puncture. One hundred sixty ASA physical status I or II laboring parturients were randomly assigned to one of four groups. The epidural space was identified with the bevel of an 18-gauge Hustead needle directed to the patients left. It was then rotated as follows: Group 0 = no rotation, final bevel orientation left (n = 39); Group 90 = rotation 90[degree sign] clockwise, bevel cephalad (n = 43); Group 180 = rotation 180[degree sign] clockwise, bevel right (n = 36); Group 270 = rotation 270[degree sign] clockwise, bevel caudad (n = 42). A single-orifice catheter was inserted 3 cm, and analgesia was induced in a standardized fashion. Dural puncture was evenly distributed among the groups (4.4%). There were more dermatomal segments blocked, fewer one-sided blocks, and more patients comfortable at 30 min with the needle bevel directed cephalad. Using a catheter inserted through a needle oriented in the cephalad direction increases the success of epidural analgesia. Implications: This prospective study shows that an epidural catheter inserted through a needle oriented in the cephalad direction increases the success of labor analgesia in the parturient. Carefully rotating the needle cephalad does not increase the risk of dural puncture, intravascular catheters, or failed blocks. (Anesth Analg 1998;87:326-30)