Fentanyl-induced cough is a risk factor for postoperative nausea and vomiting.

BACKGROUND: Postoperative nausea and vomiting (PONV) and fentanyl-induced cough (FIC) are two common anaesthesia-related events, which seem to have common risk factors. In this prospective cohort study, we investigate whether patients who have FIC during induction of anaesthesia have an increased incidence of PONV. METHODS: We studied adult non-smoking gynaecological surgical patients enrolled between July 1, 2011 and July 30, 2012. The presence of FIC during induction and the occurrence of PONV were recorded. Fentanyl-induced cough and other perioperative variables were subjected to multivariate analysis to determine the association between FIC and PONV. RESULTS: All 502 patients enrolled in this study had at least two risk factors for PONV, and 154 (31%) developed FIC. The incidence of PONV in the FIC group was higher than in the non-FIC group (56.5 vs 38.2%; P<0.0001). Multivariate logistic regression analysis found FIC to be a predictive risk factor for the development of PONV (adjusted odds ratio 2.08, 95% confidence interval 1.41-3.07). CONCLUSIONS: Non-smoking women undergoing gynaecological surgery who develop FIC during induction of anaesthesia have a higher incidence of PONV.

Multiport epidural catheters: does the air test work?

BACKGROUND: Multiport epidural catheters are popular; however, the reliability of the air test has not been evaluated with this catheter design. The authors determined the effectiveness of aspirating for blood and the air test in detecting intravascular multiorifice epidural catheters. METHODS: Three hundred women in labor underwent placement of a blunt-tip, three-hole, 20-gauge, lumbar epidural catheter. If there were no signs of spinal anesthesia, 3 ml lidocaine or bupivacaine was injected and the patient was observed for signs of spinal anesthesia. If there were no signs of spinal anesthesia, the authors injected 1 ml air through the epidural catheter while listening to the maternal precordium using a Doppler fetal heart rate monitor. Catheters through which blood was aspirated were air-tested and replaced. Patients with air-test-positive, blood-aspiration-negative catheters received 100 mg lidocaine through the catheter and were questioned about toxicity symptoms. The authors injected bupivacaine-fentanyl through aspiration-negative,air-test-negative catheters and recorded the sensory analgesic level 20 min later. RESULTS: The authors aspirated cerebrospinal fluid through one catheter and documented intravascular placement in 11 catheters. Results of the air test and blood aspiration were positive for eight catheters. Blood could not be aspirated from one air-test-positive catheter; perioral numbness developed in the patient after lidocaine injection. Blood was freely aspirated from two air-test-negative catheters. In the remaining 288 catheters, bupivacaine-fentanyl injection produced epidural analgesia in 279 patients and no effect in 9 patients. CONCLUSIONS: The authors obtained false-negative results with both catheter aspiration and the air test. Fractionating the local anesthetic dose is important when using multiorifice epidural catheters.

Lumbar sympathetic blocks speed early and second stage induced labor in nulliparous women.

BACKGROUND: Rapid cervical dilation reportedly accompanies lumbar sympathetic blockade, whereas epidural analgesia is associated with slow labor. The authors compared the effects of initial lumbar sympathetic block with those of epidural analgesia on labor speed and delivery mode in this pilot study. METHODS: At a hospital not practicing active labor management, full-term nulliparous patients whose labors were induced randomly received initial lumbar sympathetic block or epidural analgesia. The latter patients received 10 ml bupivacaine, 0.125%; 50 microg fentanyl; and 100 microg epinephrine epidurally and sham lumbar sympathetic blocks. Patients to have lumbar sympathetic blocks received 10 ml bupivacaine, 0.5%; 25 microg fentanyl; and 50 microg epinephrine bilaterally and epidural catheters. Subsequently, all patients received epidural analgesia. RESULTS: Cervical dilation occurred more quickly (57 vs. 120 min/cm cervical dilation; P = 0.05) during the first 2 h of analgesia in patients having lumbar sympathetic blocks (n = 17) than in patients having epidurals (n = 19). The second stage of labor was briefer in patients having lumbar sympathetic blocks than in those having epidurals (105 vs. 270 min; P < 0.05). Nine patients having lumbar sympathetic block and seven having epidurals delivered spontaneously, whereas seven patients having lumbar sympathetic block and seven having epidurals had instrument-assisted vaginal deliveries. Cesarean delivery for fetal bradycardia occurred in one patient having lumbar sympathetic block. Cesarean delivery for dystocia occurred in five patients having epidurals compared with no patient having lumbar sympathetic block (P = not significant). Visual analog pain scores differed only at 60 min after block. CONCLUSIONS: Nulliparous parturients having induced labor and receiving initial lumbar sympathetic blocks had faster cervical dilation during the first 2 h of analgesia, shorter second-stage labors, and a trend toward a lower dystocia cesarean delivery rate than did patients having epidural analgesia. The effects of lumbar sympathetic block on labor need to be determined in other patient groups. These results may help define the tocodynamic effects of regional labor analgesia.

Effect of labor analgesia on breastfeeding success.

BACKGROUND: The effect of labor analgesia on breastfeeding success is not well defined. Some authors have hypothesized that labor analgesia may affect lactation success. The purpose of this observational study was to determine if intrapartum analgesia influenced breastfeeding success at 6 weeks postpartum in a setting that strongly supported breastfeeding. METHODS: Healthy women with uncomplicated term pregnancies who planned to breastfeed consented to a telephone interview. We recorded demographic data, labor induction status, delivery mode, and analgesic medications. At between 6 and 8 weeks postpartum, patients were asked to describe breastfeeding use, problems encountered, solutions derived, sources of support and information, and satisfaction. We created a logistic regression model using intrapartum analgesia information and controlling for demographic factors previously correlated with lactation success. RESULTS: We enrolled 189 women, contacted 177 women postpartum, and obtained complete data on 171 women. Of these, 59 percent received epidural analgesia, 72 percent breastfed fully, and 20 percent breastfed partially (> 50% of infant nutrition) at 6 weeks postpartum. After controlling for demographics and labor outcome, we could not demonstrate a correlation between breastfeeding success at 6 to 8 weeks and labor analgesia. CONCLUSIONS: In a hospital that strongly promotes breastfeeding, epidural labor analgesia with local anesthetics and opioids does not impede breastfeeding success. We recommend that hospitals that find decreased lactation success in parturients receiving epidural analgesia reexamine their postdelivery care policies.

Respiratory arrest following intrathecal injection of sufentanil and bupivacaine in a parturient.

PURPOSE: To present a case of respiratory arrest following the use of intrathecal sufentanil and bupivacaine for combined spinal-epidural anaesthesia in a healthy labouring parturient. CLINICAL FEATURES: A 20-yr-old term parturient received 10 micrograms sufentanil and 2.5 mg bupivacaine intrathecally as part of a combined spinal-epidural technique for labour analgesia. She had received no previous analgesics. Twenty-three minutes after the intrathecal injection she became unresponsive and suffered a respiratory arrest. Resuscitation included manual bag/mask ventilation with oxygen and intravenous naloxone. CONCLUSION: Respiratory arrest is a rare but potentially life-threatening complication associated with the use of intrathecal opioids for labour analgesia. Vigilance in post-procedure patient monitoring is imperative.

The influence of epidural needle bevel orientation on spread of sensory blockade in the laboring parturient.

UNLABELLED: 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 patient's 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 patient's left. It was then rotated as follows: Group 0 = no rotation, final bevel orientation left (n = 39); Group 90 = rotation 90 degrees clockwise, bevel cephalad (n = 43); Group 180 = rotation 180 degrees clockwise, bevel right (n = 36); Group 270 = rotation 270 degrees 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.

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 microg 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 microg (SE, 0.6 microg; 95% CI, 2.96 to 0.54 microg). 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.

Epidural labor analgesia and the incidence of cesarean delivery for dystocia.

UNLABELLED: We performed this retrospective study to examine the changes in cesarean delivery rates associated with the establishment of a labor epidural service. In April 1993, St. Louis Regional Medical Center established an on-demand labor epidural service. We obtained demographic data for all patients and reviewed the operative records of all patients undergoing cesarean section who delivered 12 mo before and 16 mo after the start of the labor epidural service. We compared labor epidural rates and total and nulliparous dystocia cesarean delivery rates before and after the epidural service started and among patients who did and did not receive labor epidural analgesia when it was available. Included were 3195 patients who delivered before and 3733 patients who delivered after epidural analgesia became available. Labor epidural rates were 1.2% vs 29.4% for the Before group versus the After group (P < 0.001). Total (9.1% vs 9.7%) and nulliparous dystocia (5.7% vs 6.4%) cesarean delivery rates did not significantly change with the availability of epidural analgesia. However, the total (11.6% vs 8.8%; P = 0.009) and dystocia (8.0% vs 1.0%; P = 0.001) cesarean delivery rates were higher among patients who received epidural analgesia when it was available. We conclude that epidural labor analgesia is associated with, but does not cause, cesarean delivery for dystocia. IMPLICATIONS: Increased epidural analgesia use did not change the overall dystocia cesarean delivery rate, although dystocia was more common among women who chose an epidural analgesia. Consequently, limiting epidural availability will not affect cesarean delivery rates. The evidence does not support advising patients that epidural labor analgesia increases the risk of cesarean delivery.

Effect of epidural vs parenteral opioid analgesia on the progress of labor: a meta-analysis.

CONTEXT: Epidural labor analgesia, if selected by the patient, is associated with high cesarean delivery rates. Results of randomized trials comparing rates of cesarean delivery using epidural anesthesia vs parenteral opioids are inconsistent. OBJECTIVE: To review the effects of epidural vs parenteral opioid analgesia on cesarean delivery rates. DATA SOURCES: Studies were identified by searching MEDLINE from January 1966 through January 1998, the Cochrane Database of Perinatal Trials, and relevant nonindexed journals and abstracts. STUDY SELECTION: We included all studies that randomized patients to epidural vs parenteral opioid labor analgesia. DATA EXTRACTION: Two authors independently extracted data from 10 trials enrolling 2369 patients. Odds ratios (ORs) for categorical data, weighted mean differences (WMDs) for continuous data, and 95% confidence intervals (CIs) were calculated using a random-effects model. DATA SYNTHESIS: The risk of cesarean delivery did not differ between patients receiving epidural (8.2%) vs parenteral opioid (5.6%) analgesia (OR, 1.5; 95% CI, 0.81-2.76). Epidural patients had longer first (WMD, 42 minutes; 95% CI, 17-68 minutes) and second (WMD, 14 minutes; 95% CI, 5-23 minutes) labor stages. While epidural patients were more likely to have instrumented delivery (OR, 2.19; 95% CI, 1.32-7.78), they were no more likely to have instrumented delivery for dystocia (OR, 0.68; 95% CI, 0.31-1.49). After epidural analgesia, neonates were less likely to have low 5-minute Apgar scores (OR, 0.38; 95% CI, 0.18-0.81) or to need naloxone (OR, 0.24; 95% CI, 0.07-0.77). Women receiving epidural analgesia had lower pain scores during the first (WMD, -40 mm on a 100-mm scale; 95% CI, -42 to -38 mm) and second (WMD, -29 mm; 95% CI, -38 to -21 mm) stages of labor. The odds of dissatisfaction were lower with epidural analgesia (OR, 0.25; 95% CI, 0.20-0.32). CONCLUSIONS: Epidural labor analgesia is not associated with increased rates of instrumented vaginal delivery for dystocia or cesarean delivery. Patients receiving epidural analgesia have longer labors. Patient satisfaction and neonatal outcome are better after epidural than parenteral opioid analgesia.

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 micrograms 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 micrograms/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 sufentanil's analgesic efficacy.

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 micrograms 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 micrograms (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 micrograms than when given without prior dural puncture and intrathecal injection.

A comparison of meperidine and lidocaine for spinal anesthesia for postpartum tubal ligation.

BACKGROUND AND OBJECTIVES: This study compares the anesthetic potency, duration, and side effects of subarachnoid meperidine and lidocaine for postpartum tubal ligation. METHOD: Twenty healthy, unpremedicated postpartum women gave written informed consent to participate in this randomized double-blind study. After intravenous infusion of 200 mL physiologic salt solution, patients received subarachnoid injections from either lidocaine 70 mg in 7.5% glucose or meperidine 60 mg in saline while lying in the right lateral position. Heart rate, blood pressure, sensory and motor block, pain, nausea, and pruritus were recorded at intervals for up to 12 hours after injection. The time to first postoperative analgesic was also recorded. RESULTS: There were no differences between the groups in demographics, heart rate, or blood pressure at any time. Sensory or motor block developed slightly faster in the lidocaine group. One patient in each group required general anesthesia owing to inadequate sensory block. Beginning at 60 minutes, meperidine patients experienced more pruritus (P < .05). Lidocaine patients had more postoperative pain (P < .01) and required supplemental analgesia 83.3 +/- 32.7 minutes after induction versus 447.6 +/- 184.0 minutes in the meperidine group. No patient's oxygen saturation fell below 95%. Patients expressed equal satisfaction with both agents. CONCLUSION: Subarachnoid meperidine and lidocaine both provide adequate anesthesia for postpartum tubal ligation. Meperidine provided longer postoperative analgesia.

Ilioinguinal iliohypogastric nerve blocks--before or after cesarean delivery under spinal anesthesia?

Preoperative local anesthetic blockade of somatosensory pathways involved with skin incision and other noxious perioperative stimuli may "preempt" or attenuate the postoperative pain response. Since the Pfannenstiel incision lies within the L1 dermatome, bilateral ilioinguinal, iliohypogastric nerve blocks (IINBs) should provide analgesia after low transverse cesarean section. We designed this study to compare the analgesic effect of IINBs placed before or after cesarean delivery. Forty-six patients undergoing cesarean delivery with spinal anesthesia were enrolled. Patients were randomly assigned to one of three groups: Before, After, or None. Bilateral IINBs were placed with 0.5% bupivacaine, 10 mL to each side. Twenty-two patients had IINBs placed before surgery (11 failed blocks), 12 had blocks placed after surgery, and 12 had no block. Morphine, through a patient-controlled analgesia (PCA) pump, provided additional postoperative analgesia. A blinded observer assessed 24-h morphine use as well as patient satisfaction and pain scores ("incisional" and "overall") for 96 h. Although there were no consistent differences in pain scores among the groups, patients in the After group occasionally reported more pain than those in the Before and None groups. Patient satisfaction and morphine use did not differ among the groups. We conclude that there is no benefit to ilioinguinal nerve blocks, either before or after surgery, in patients who receive spinal anesthesia for elective cesarean delivery. Our finding of increased pain in the After group is perplexing and requires confirmation.