Epidural catheter replacement rates with dural puncture epidural labor analgesia compared with epidural analgesia without dural puncture: a retrospective cohort study.

BACKGROUND: Lumbar epidural analgesia (LEA) is commonly used for labor analgesia but up to 13% of epidural catheters fail and require replacement. Combined spinal-epidural analgesia is associated with a lower catheter failure rate. Few data exist regarding catheter replacement rates after dural-puncture epidural (DPE). We conducted a retrospective analysis comparing catheter failure rates between epidural and DPE techniques. METHODS: This retrospective single-center trial reviewed all labor neuraxial analgesia procedures among 18 726 women across five years, and identified 810 DPE and 2667 LEA procedures. Catheter failure rates, consisting of replacement or requirement of general anesthesia for cesarean delivery, were compared. Propensity score matching was used to balance the groups. RESULTS: Dural-puncture epidural was associated with significantly fewer catheter failures compared with LEA (74/759 vs. 49/759, odds ratio 0.64, 95% CI 0.44 to 0.93, P=0.02). Sensitivity analysis excluding cases of general anesthesia confirmed this relationship. Risk factors identified for catheter failure included age, body mass index, and nulliparity. Dural-puncture epidural was associated with a longer mean time to catheter replacement (918 min vs. 609 min, P=0.04). Kaplan-Meier and Cox multivariate analyses confirmed this relationship. There was no significant difference in the requirement for epidural analgesia supplementation, but DPE required supplementation significantly later than LEA. There was no difference in the rate of headache or epidural blood patch between groups. CONCLUSIONS: Dural-puncture epidural is associated with fewer catheter failures and replacements than LEA, without an increase in the rate of post-dural puncture headache or epidural blood patch.

Low-dose intravenous dexmedetomidine reduces shivering following cesarean delivery: a randomized controlled trial.

BACKGROUND: Intravenous dexmedetomidine 30 µg reduces shivering after cesarean delivery but can result in sedation and dry mouth. We hypothesized that prophylactic administration of 10 µg of IV dexmedetomidine would reduce the patient-reported severity of shivering after cesarean delivery, without an increased incidence of side effects. METHODS: After institutional review board approval and informed written consent, women undergoing scheduled cesarean delivery with spinal or combined spinal-epidural anesthesia were randomized to receive either intravenous normal saline or dexmedetomidine 10 µg immediately after delivery. The primary outcome was a patient-rated subjective shivering score using a 10-cm visual analog scale at 30 and 60 min after arrival in the Post-Anesthesia Care Unit. Secondary outcomes included subjective scores for pain, nausea, itching, dry mouth, and sedation, as well as 24-h medication administration and investigator-rated observations of shivering, vomiting, pruritus, and sedation. Repeated measures ANOVA with Tukey-Kramer multiple-comparison test was applied for primary outcomes. RESULTS: One hundred patients were enrolled, and 85 completed the study and were included in analysis. The mean ±â€¯SD shivering score in the dexmedetomidine group was significantly lower by repeated measures analysis than among controls across the first 60 min (P=0.0002), and individually at both 30 and 60 min (placebo 1.8 ±â€¯2.6 vs. dexmedetomidine 0.6 ±â€¯1.4 at 30 min; 1.2 ±â€¯2.1 vs. 0.3 ±â€¯0.6 at 60 min; both P <0.01). Patient-rated and observer-rated side effects did not significantly differ between groups. CONCLUSIONS: Prophylactic administration of intravenous dexmedetomidine 10 µg after delivery reduces shivering without notable side effects.

Heterozygote carriers of mutations in the F11 gene, encoding Factor XI, have normal coagulation by thromboelastography during pregnancy.

BACKGROUND: Evidence to guide clinical decision-making in pregnant women who are usually asymptomatic, but identified as heterozygote carriers of F11 mutations, is lacking. We hypothesized that women identified on prenatal screening as heterozygous for a mutation in the F11 allele would have minimal evidence of an in vitro coagulation abnormality. METHODS: We prospectively enrolled women identified by prenatal screening as F11 mutation carriers and pregnant women who were presumed to be normal as controls. We collected blood during antepartum visits or at presentation for delivery and assessed Factor XI (FXI) coagulant activity level, as well as whole-blood coagulation, by thromboelastography. RESULTS: F11 mutation carriers had lower serum FXI activity levels than controls (51.2 ±â€¯8.5% vs 94.1 ±â€¯19.4%; P <0.0001). Thromboelastography values of all control subjects and F11 mutation carriers were within the normal range. The R-time was slightly longer in F11 mutation carriers (5.3 ±â€¯1.0 s vs 4.2 ±â€¯0.8 s, P <0.002), but no other statistically significant differences in thromboelastogram parameters were identified between groups. CONCLUSIONS: Despite lower FXI activity in the F11 mutation group, we found minimal differences in whole-blood measures of coagulation using thromboelastography. These findings support our hypothesis that a single copy of an F11 mutation does not produce significant evidence of an in vitro coagulation abnormality. Thromboelastography might be useful in determining the risk of neuraxial anesthesia in pregnant women, but additional work is required to establish the validity of this test.

What's new in clinical obstetric anesthesia in 2015?

Each calendar year the Society for Obstetric Anesthesia and Perinatology invites an individual to conduct a review of the medical literature, identifying clinically relevant publications of interest to the obstetric anesthesia provider. This report of that effort covers the publications from 2015 and includes the categories of anesthesia and analgesia, complications of neuraxial procedures, and the effects of anesthesia on the fetus. Neuraxial procedures represent the foundation of obstetric anesthesia; advances in anesthesia and analgesia include novel modes of administration, and refinements in care of the medically complex patient. In addition to labor analgesia, investigations into post-cesarean recovery address challenges in pain control, patients with obstructive sleep apnea, and treatment protocols intended to improve patient care, notably an enhanced-recovery pathway. Because complications are inevitable, this review identifies investigations on the more common complications of neuraxial procedures, such as hypotension, maternal and fetal bradycardia, and post-dural puncture headache. There were several innovative reports attempting to address these complications, including the use of norepinephrine infusion for the prevention of spinal-induced hypotension, ephedrine for the prevention of fetal bradycardia after combined spinal-epidural analgesia, and pharmacologic treatment of post-dural puncture headache. Not all of these treatments were successful. Finally, there are potential effects of anesthesia on the fetal/neonatal brain, much of which remains poorly defined. An analysis of recent papers suggests that epidural fever is not an independent cause of adverse neurologic fetal injury. On the other hand, evidence continues to grow to support the hypothesis that anesthetic drugs impact neonatal neurologic outcome.

Observational study of changes in epidural pressure and elastance during epidural blood patch in obstetric patients.

BACKGROUND: During an epidural blood patch, we inject blood until the patient describes mild back pressure, often leading to injection of more than 20 mL of blood. We undertook this study to measure the epidural pressures generated during an epidural blood patch and to identify the impact of volume on epidural elastance in obstetric patients. METHODS: This study was performed in postpartum patients who presented for an epidural blood patch with symptoms consistent with a postdural puncture headache. After identification of the epidural space using loss of resistance to air or saline, we measured static epidural pressure after each 5-mL injection of blood. Models were then fitted to the data and the epidural elastance and compliance calculated. RESULTS: Eighteen blood patches were performed on 17 patients. The mean final volume injected was 18.9±7.8 mL [range 6-38 mL]. The mean final pressure generated was 13.1±13.4 mmHg [range 2-56 mmHg]. A curvilinear relationship existed between volume injected and pressure, which was described by two models: (1) pressure=0.0254×(mL injected)(2)+0.0297 mL, or (2) pressure=0.0679×mL(1.742). The value for r2 was approximately 0.57 for both models. We found no correlation between the final pressure generated and the success of the epidural blood patch. CONCLUSIONS: We found a curvilinear relationship between the volume of blood injected during an epidural blood patch and the pressure generated in the epidural space. However, there was a large variation in both the volume of blood and the epidural pressure generated. The clinical importance of this finding is not known. A larger study would be required to demonstrate whether pressure is a predictor of success.

A randomized prospective study comparing two flexible epidural catheters for labour analgesia.

BACKGROUND: Previous studies evaluating stiff epidural catheters found that the three-holed design provided superior labour analgesia compared with an end-holed design. This was believed due to improved medication distribution. Recently, flexible epidural catheters with both designs have been shown to be superior to the stiff epidural catheters. We investigated the success of labour analgesia comparing the flexible three-holed with the flexible end-holed epidural catheter. METHODS: This was a prospective, single-blinded randomized study. We enrolled 500 parturients in active labour. The primary outcome was complete relief of labour pain assessed at 30 min. We also assessed the occurrence of paresthesias, intravascular and intrathecal placement, catheter replacement, and treatment of breakthrough pain during labour. Comparisons were made using Pearson's chi(2), with significance determined at the 0.05 level. RESULTS: Four hundred and ninety-three subjects completed the study. Initial analgesia was similar (complete labour analgesia: end-holed=85% vs 80% 95% CI of difference: 13% to -3%; P=NS). The incidence of paresthesia was similar (end-holed=3.6% vs 5.3%; P=NS). There was one intrathecal and three intravascular catheters in the three-holed group and two intravascular catheters in the end-holed group. The number of supplemental boluses and catheter replacements required during labour was similar between the groups. CONCLUSIONS: There were no differences in the initial analgesia success rate, complications, or labour analgesia between end-hole vs multi-hole flexible epidural catheters.

Evaluation of cranberry tablets for the prevention of urinary tract infections in spinal cord injured patients with neurogenic bladder.

STUDY DESIGN: Randomized, double blind, placebo-controlled trial with a crossover design. OBJECTIVE: To evaluate cranberry tablets for the prevention of urinary tract infection (UTI) in spinal cord injured (SCI) patients. SETTING: Spinal Cord Injury Unit of a Veterans Administration Hospital, MA, USA. METHODS: Subjects with spinal cord injury and documentation of neurogenic bladder were randomized to receive 6 months of cranberry extract tablet or placebo, followed by the alternate preparation for an additional 6 months. The primary outcome was the incidence of UTI. RESULTS: Forty-seven subjects completed the trial. We found a reduction in the likelihood of UTI and symptoms for any month while receiving the cranberry tablet (P<0.05 for all). During the cranberry period, 6 subjects had 7 UTI, compared with 16 subjects and 21 UTI in the placebo period (P<0.05 for both number of subjects and incidence). The frequency of UTI was reduced to 0.3 UTI per year vs 1.0 UTI per year while receiving placebo. Subjects with a glomerular filtration rate (GFR) greater than 75 ml min(-1) received the most benefit. CONCLUSION: Cranberry extract tablets should be considered for the prevention of UTI in SCI patients with neurogenic bladder. Patients with a high GFR may receive the most benefit. SPONSORSHIP: Spinal Cord Research Foundation, sponsored by the Paralyzed Veterans of America.

Intrathecal morphine reduces breakthrough pain during labour epidural analgesia.

BACKGROUND: When using the combined spinal-epidural (CSE) technique for labour analgesia, parturients often experience breakthrough pain after the spinal medication has receded. We tested the hypothesis that a small dose of intrathecal morphine would reduce breakthrough pain. METHODS: This was a randomized, double-blind, placebo-controlled trial. Subjects were randomized to receive either 100 microg of morphine (MS) or placebo (PLCB) with the spinal injection of bupivacaine and fentanyl. Assessments included need for supplementation during labour analgesia, use of pain medications for 24 h after delivery, and side-effects. The primary end-point was the rate of breakthrough pain. RESULTS: Sixty subjects were enrolled, 55 subjects completed the trial. The MS group had a significantly lower rate of breakthrough pain than the PLCB group [0.6 (0.6) vs 1.1 (0.8) episodes per patient; P < 0.01], and longer time to first episode of breakthrough pain (300 vs 180 min; P = 0.03). The MS group used 75% less opioid medications during the subsequent 24 h, but had a 17% incidence of nausea. CONCLUSIONS: The addition of small dose of morphine to the spinal component of the CSE technique improved the effectiveness of epidural labour analgesia and reduced the need for pain medications over 24 h, but resulted in a small increase in nausea.

An analysis of the need for anesthetic interventions with differing concentrations of labor epidural bupivacaine: an observational study.

BACKGROUND: Labor epidural analgesia techniques using lower concentrations of bupivacaine are designed to maintain pain control with fewer side effects such as hypotension and motor block. However, the increase in sensation may allow breakthrough pain resulting in the need for additional interventions. We examined the number of interventions, both for analgesia and for treatment of side effects, required when using three concentrations of bupivacaine. METHODS: Retrospective observational investigation examining 4493 women who received epidural analgesia during two periods. In the first period, higher concentrations of bupivacaine were used (0.125% and 0.0625%, both with fentanyl 2 microg/mL). In the second period, a very low concentration was used (0.04% plus fentanyl 1.7 microg/mL and epinephrine 1.7 microg/mL). Outcomes were compared using univariate tests, and multivariate Poisson regression was used to identify independent factors influencing interventions. RESULTS: The frequencies of interventions were similar for women receiving bupivacaine concentrations of 0.04% (1.4+/-2.0) and 0.125% (1.5+/-2.0), while women receiving the 0.0625% solution required more interventions (1.8+/-2.3; P<0.001). Women who received 0.04% or 0.0625% bupivacaine required more treatment of breakthrough pain (P<0.002), while those receiving 0.125% bupivacaine required more treatment for hypotension and motor block (P<0.05). Multivariate Poisson regression showed that duration of treatment, maternal age and body mass index were independent factors for the number of interventions. CONCLUSIONS: Neither the total interventions nor intervention rate per hour varied significantly with the concentrations of bupivacaine used in this study. Lower concentrations produced fewer side effects including hypotension, while the higher concentration resulted in less breakthrough pain.

Hypothermia after cesarean delivery and its reversal with lorazepam.

BACKGROUND: Intrathecal morphine can produce hypothermia in animals. This side effect has been reported in humans, but has not been thoroughly studied in obstetrics. METHODS: We report a series of 14 patients with presumed morphine-induced hypothermia. All patients had post-cesarean temperatures <35.8 degrees C, and complained of associated symptoms of diaphoresis and subjective feeling of being hot. After collecting this series, we determined the incidence of this side effect in an observational study of 100 consecutive patients. All patients had spinal anesthesia with bupivacaine, morphine and fentanyl. RESULTS: In the case series, four of 14 patients were treated conservatively, and 10 were given lorazepam. Those treated conservatively had 6h of hypothermia and symptoms; women given lorazepam had a cessation of symptoms and a rapid increase in temperature. In the observational study, 6% (95% Confidence Interval: 1-10%) experienced symptomatic hypothermia lasting for several hours after the end of surgery (120-360 min). We found no statistical association with any demographic or obstetric characteristic. CONCLUSION: We conclude that symptomatic hypothermia is an occasional side effect of cesarean section under spinal anesthesia. We believe this syndrome is due to intrathecal morphine. While the duration is limited to 6h, lorazepam appears to treat both hypothermia and symptoms.

Epidural anesthesia in a parturient with neurofibromatosis type 2 undergoing cesarean section.

Neurofibromatosis type 2 (NF2) is a rare condition only recently recognized. We present a case describing successful regional analgesia in a parturient with NF2 after thorough imaging revealed no tumors within the epidural space. The presence of tumors within the spinal cord and nerve roots and their potential enlargement during pregnancy make routine neuraxial anesthesia hazardous in patients with NF2. Lumbosacral imaging before performing regional anesthesia is recommended.

Low dose intrathecal ropivacaine with or without sufentanil provides effective analgesia and does not impair motor strength during labour: a pilot study.

PURPOSE: Although ropivacaine has been used to provide spinal anesthesia in the surgical population, its intrathecal administration for labour analgesia has only recently been described. We evaluated the effects of low dose intrathecal ropivacaine with or without sufentanil for labour analgesia. METHODS: Thirty-six term parturients in active labour were randomly assigned to receive 3 mg of intrathecal ropivacaine (group R) or 3 mg ropivacaine with 10 microg of sufentanil (group RS). Patients were evaluated by a blinded observer for hypotension, linear analogue score (VAS 0-100) for labour pain, motor power in the lower limbs, onset of analgesia, sensation to cold and pin prick, duration of analgesia, and neonatal Apgar scores. The following day patients were assessed for satisfaction, headache and neurologic deficit. RESULTS: The mean duration of analgesia in the R group was 41.4 +/- 4.9 min and 95.0 +/- 6.1 min in the RS group (mean +/- SEM, P=0.0001). All subjects had satisfactory analgesia at five minutes, although analgesia from the ropivacaine- sufentanil combination was superior to that provided by ropivacaine alone. Total duration of labour was no different between the groups (R- 306 +/- 34, RS- 384 +/- 44 min, P=0.17). No patient showed evidence of motor block. All patients were satisfied with the labour analgesia. No neurological complications were observed. CONCLUSIONS: Low dose ropivacaine provides effective analgesia during labour via the intrathecal route. It can be mixed with sufentanil in the above-mentioned concentrations to improve both the quality and duration of analgesia. Fetal outcome remains favourable. It may provide minimal or no motor block, to facilitate ambulation.

Predictors of breakthrough pain during labor epidural analgesia.

UNLABELLED: Parturients who receive labor epidural analgesia may experience breakthrough pain that requires supplemental medications. We investigated the factors associated with breakthrough pain. This prospective observational study included 1963 parturients who received epidural analgesia. Subjects were categorized into two groups on the basis of the number of episodes of breakthrough pain: the Recurrent Breakthrough Pain (RBP) group experienced three or more episodes. Univariate and multivariate regression analyses were used to evaluate factors associated with the RBP group. By multivariate analysis, nulliparity, heavier fetal weight, and epidural catheter placement at an earlier cervical dilation were found to be independently associated with the RBP group. These factors may predict which parturients' analgesia may be complicated by breakthrough pain. Parturients who received a combined spinal/epidural technique were less likely to be associated with the RBP group. The combined spinal/epidural technique may be superior to conventional epidural anesthesia, because breakthrough pain occurred less often. It is interesting to note that the characteristics that are associated with the RBP group are similar to those that have been associated with increased severity of maternal pain. IMPLICATIONS: Nulliparity, heavier fetal weight, and epidural catheter placement at an early cervical dilation are predictors of breakthrough pain during epidural labor analgesia. The combined spinal/epidural technique may be associated with a decreased incidence of breakthrough pain.

An association between severe labor pain and cesarean delivery.

UNLABELLED: The relationship between epidural analgesia and cesarean delivery remains controversial. Several studies have documented an association, although others have not. This inconsistency may result from an association between severe labor pain and dystocia. We hypothesized that dystocia causes severe labor pain, such that more epidural medication is required to maintain comfort. We examined the relationship between labor outcome and severe pain, defined by the number of supplemental epidural boluses. We retrospectively reviewed the anesthesia records of 4493 parturients who received small-dose labor epidural analgesia. An independent association was found between operative delivery and maternal age, body mass index, nulliparity, fetal weight, induction of labor, and the number of boluses required during labor. By using multivariate analysis, the odds ratio of cesarean delivery among women who required at least three boluses was 2.3 compared with those who required two boluses or less. No association was found between the concentration of bupivacaine in the epidural infusion and operative delivery. Because women with cesarean deliveries appeared to have more pain, degree of labor pain may be a confounding factor in studies examining epidural analgesia and outcome. IMPLICATIONS: This is a retrospective observational study demonstrating an association between labor pain and cesarean delivery. Our results provide an alternative explanation of why epidural analgesia is associated with cesarean delivery.