Intrathecal catheter use after accidental dural puncture in obstetric patients: literature review and clinical management recommendations.

If an accidental dural puncture occurs, one option is to insert a catheter and use it as an intrathecal catheter. This avoids the need for a further injection and can rapidly provide labour analgesia and anaesthesia for caesarean section. However, there are no recommendations for managing intrathecal catheters and, therefore, significant variation in clinical practice exists. Mismanagement of the intrathecal catheter can lead to increased motor block, high spinal anaesthesia, drug error, hypotension and fetal bradycardia. Care must be taken with an intrathecal catheter to adhere to strict aseptic technique, meticulous labelling, cautious administration of medications and good communication with the patient and other staff. Every institution considering the use of intrathecal catheters should establish a protocol. For labour analgesia, we recommend the use of dilute local anaesthetic agents and opioids. For caesarean section anaesthesia, gradual titration to the level of the fourth thoracic dermatome, with full monitoring, in a facility equipped to manage complications, should be performed using local anaesthetics combined with lipophilic opioids and morphine or diamorphine. Although evidence of the presence and duration of intrathecal catheters on the development of post-dural puncture headache and need for epidural blood patch is limited, we suggest considering leaving the intrathecal catheter in for 24 hours to reduce the chance of developing a post-dural puncture headache while maintaining precautions to avoid drug error and cerebrospinal fluid leakage. Injection of sterile normal saline into the intrathecal catheter may reduce post-dural puncture headache. The level of evidence for these recommendations was low.

Feasibility study of a force-sensing resistor device for landmark detection for neuraxial procedures and anesthesiologists' impact on device improvement.

The standard of care for neuraxial procedures is landmark palpation to determine the site of placement. This research study aimed to test the primary feasibility of VerTouch™, a force-sensing resistor device, to identify landmarks for the initiation of neuraxial procedures. Patients were recruited at the time of labour epidural, or when consenting for spinal anaesthesia for caesarean delivery at a single centre. The clinical team used the device to create a pressure map image of the bony spine. If they felt confident, they used the device guide to make a mark on the patient's back. If the mark was used, total insertions and redirections, combined as passes, of the needle during the procedure were counted for secondary outcome analysis. A total of 101 parturients were recruited, and the provider felt confident making a mark based on the imaging in 96.9% of cases. Device success (completion using the mark and ≤4 total passes) occurred in 91.4% of cases. This feasibility study showed that the primary outcome, the provider using the device to make a mark, was successful. In addition, based on comparing passes with historical data, the Vertouch™ device showed promise for future use to minimise needle manipulation in neuraxial procedures.

Ultrasound-guided transmuscular quadratus lumborum catheters for elective caesarean section: A protocol for a single-centre, double-blind randomised trial.

BACKGROUND: Management of moderate-to-severe post-operative pain after elective caesarean section (ECS) is internationally primarily based on either epidural catheters or opioids. However, both techniques are associated with some undesirable adverse events. Bilateral transmuscular quadratus lumborum (TQL) block has proven to reduce opioid consumption significantly in the first 24 post-operative hours following ECS and prolong time to first opioid (TFO) (Hansen CKD, Steingrimsdottir M, Laier GE, et al. Reg Anesth Pain Med. 2019; 10.1136/rapm-2019-100540). We present a randomised controlled trial aiming to investigate whether continuous analgesia via bilateral TQL catheters can prolong TFO after ECS. METHODS: This study is a double-blind, randomised, placebo-controlled trial. Patients should be 18 years or older and scheduled for ECS under spinal anaesthesia to be included. Main exclusion criteria are inability to cooperate, excessive daily intake of opioids and difficult ultrasound visualisation of muscular and fascial structures. Participants are randomised to receive ultrasound-guided injection of either 30 mL ropivacaine 0.2% bilaterally and an elastomeric pump containing 0.2% ropivacaine, or 30 mL saline bilaterally and an elastomeric pump containing saline, 2 hours after catheter placement. The primary endpoint is TFO. Secondary outcomes include pain intensity on a numeric rating scale (NRS), accumulated morphine consumption during 24 hours, displacement frequency of catheters and morphine-related adverse events. RECRUITMENT PERIOD: Four patients were included from September 2018 to November 2018. Inclusion was resumed in June 2019 and will continue until 24 patients with useful data have been included in the trial. Expected inclusion period is 10-14 months. TRIAL REGISTRATION: ClinicalTrials.gov identifier: NCT03663478. EudraCT: 2017-003625-15.

Comparison of Programmed Intermittent Epidural Boluses With Continuous Epidural Infusion for the Maintenance of Labor Analgesia: A Randomized, Controlled, Double-Blind Study.

BACKGROUND: Programmed intermittent epidural boluses may improve the spread of local anesthetics compared to continuous epidural infusion, improving labor analgesia and obstetric outcomes. However, there are limited data from studies using commercially available pumps capable of coadministering programmed intermittent epidural boluses or continuous epidural infusion with patient-controlled epidural analgesia. Therefore, we performed this prospective, randomized, double-blind study to compare the impact of programmed intermittent epidural boluses versus continuous epidural infusion on labor analgesia and maternal/neonatal outcomes. We hypothesized that programmed intermittent epidural boluses will result in lower patient-controlled epidural analgesia consumption compared to that with continuous epidural infusion. METHODS: Following standardized initiation of epidural labor analgesia, women were randomized to receive 0.1% ropivacaine with 2 µg/mL fentanyl as 6-mL programmed intermittent epidural boluses every 45 minutes or continuous epidural infusion at 8 mL/h in a double-blind fashion with similar patient-controlled epidural analgesia settings in both groups. The primary outcome was patient-controlled epidural analgesia consumption per hour. Secondary outcomes included a need for physician interventions, patterns of patient-controlled epidural analgesia use, motor blockade, number of patients who developed hypotension, pain scores, duration of second stage of labor, mode of delivery, and maternal satisfaction. RESULTS: We included 120 patients (61 in programmed intermittent epidural boluses group and 59 in continuous epidural infusion group) in the analysis. The median (interquartile range) patient-controlled epidural analgesia volume consumed per hour was not significantly different between the groups: 4.5 mL/h (3.0-8.6 mL/h) for the continuous epidural infusion group and 4.0 mL/h (2.2-7.1 mL/h) for the programmed intermittent epidural boluses group (P = .17). The Hodges-Lehmann location shift estimate of the difference (95% CI) from the continuous epidural infusion to the programmed intermittent epidural boluses group is 0.9 mL/h (-0.4 to 2.2 mL/h). There were also no significant differences between the groups in any of the secondary outcomes except for higher median (interquartile range) patient-controlled epidural analgesia attempts per given ratio per hour in the programmed intermittent epidural bolus group (0.17 [0.10-0.30] vs 0.12 [0.08-0.18]; P = .03) and more motor block in the continuous epidural infusion group (those with Bromage score <5, 27.5% vs 50.0%; P = .03). CONCLUSIONS: Under the conditions of our study, we did not find improved outcomes with programmed intermittent epidural boluses compared to continuous epidural infusion except for less motor block with programmed intermittent epidural boluses. Future studies should assess whether smaller but clinically important differences exist and evaluate different parameters of programmed intermittent epidural boluses to optimize analgesia and outcomes with this mode of analgesia.

Use of a novel non-invasive respiratory monitor to study changes in pulmonary ventilation during labor epidural analgesia.

Measuring continuous changes in maternal ventilation during labor neuraxial analgesia is technically difficult. Consequently, the magnitude of pulmonary minute ventilation (MV) alterations following labor analgesia remains unknown. We hypothesized that a novel, bio-impedance based non-invasive respiratory monitor would provide this information. Furthermore, we sought to determine if an association between changes in MV and maternal temperature existed. Following calibration with a Haloscale Standard Wright Respirometer, the ExSpiron respiratory volume monitor (RVM) measured MV, respiratory rate (RR), and tidal volume (TV) in 41 term parturients receiving epidural analgesia. Simultaneously, maternal oral temperatures were recorded at pre-specified hourly intervals after epidural analgesia initiation until delivery. Cumulative MV changes were calculated as the integral of MV change over time: MV [Formula: see text], where T represents the time between epidural placement and variable measurement. The association between changes in MV and cumulative MV versus maternal temperature was determined by comparing patients whose temperature did or did not increase by ≥ 0.5 °C. After initiation of epidural analgesia, MV decreased by 11.1 ± 27.6% [mean ± SD] at 30 min, p = 0.006, and 19.8 ± 26.1% at 2 h compared to baseline (12.6 ± 7.3 L/min at baseline vs. 15.3 ± 6.3 L/min at 2 h, p < 0.001), Minute ventilation remained decreased at 4 h by 14.3 ± 31.4% (p = 0.013). The cumulative MV also decreased by 437 ± 852 L [mean ± SD], p = 0.009) at 2 h and by 795 ± 1431 L, p < 0.001) at 4 h following epidural analgesia initiation, compared to baseline. The association between changes in cumulative MV and maternal temperature following epidural placement was weak (R < 0.3); however, a decrease in MV at 30 min (p = 0.002) and cumulative MV at 2 h (p = 0.012) was observed in women whose temperature increased by at least 0.5 °C during labor. Our findings suggest that RVM can be a useful noninvasive technology to investigate pulmonary physiology during labor. The association between maternal MV and temperature change during labor analgesia deserves further investigation.Trial Registrationwww.clinicaltrials.gov (NCT02339389).

Do Epidural Catheter Size and Flow Rate Affect Bolus Injection Pressure in Different Programmed Intermittent Epidural Bolus Regimens? An In Vitro Study.

BACKGROUND: The optimal programmed intermittent epidural bolus regimen for labor analgesia remains unknown. Some studies indicate that better drug spread in the epidural space results from greater injection pressure; however, there is a lack of data regarding the maximum pressure generated by epidural bolus injection using different catheters and flow rates. METHODS: We evaluated the flow and pressure characteristics of 11 commonly used epidural catheters combined with 3 different infusion pumps that deliver epidural infusions according to the programmed intermittent epidural bolus regimen. Pressure changes were measured over time at flow rates of 100, 250, and 400 mL·hour and with a bolus volume of 10 mL. To account for repeated measures, linear mixed models were used. Features were selected with a backward stepwise procedure continued until only statistically significant variables were left in the model. RESULTS: We performed 660 measurements. The mean maximal pressure generated during bolus injection ranged from 86 to 863 mm Hg for different flow rates and catheter designs. The interaction between flow rate and catheter gauge resulted in 1.31, 1.65, and 2.00 mm Hg of pressure increase for 18G, 19G, and 20G catheters, respectively, per 1 mL·hour of increased flow rate (P< .001). Analyses including wire-reinforced catheters revealed a 1.16, 1.76, and 2.36 mm Hg pressure increase for 18G, 19G, and 20G catheters, respectively, per 1 mL·hour of increased flow rate (P< .001). In some cases, it triggered the occlusion pump alarm. CONCLUSIONS: Significant differences were observed in the in vitro maximum pressure value among the various catheter and flow rate combinations with a higher pressure value for wire-reinforced catheters used in the study. The optimal flow rate and epidural catheter combination may allow for delivery of the bolus with high flow rate without triggering the occlusion alarm.

Intrapartum epidural catheter displacement: Comparison of three dressing methods (Migración de catéter epidural intraparto: Comparación de tres métodos de fijación).

AIM: To compare the effect on epidural catheter migration of three different types of dressing used in labor. INTRODUCTION: Failure of labor epidural is due to multiple factors including catheter migration. Epidural catheter migration has been showed to be related to body mass index and patient position. The dressing technique also influences catheter migration and the risk of epidural failure. METHODS: Patients were randomly allocated to one of three groups based on type of dressing of labor epidural: TegadermTM (Group T), TegadermTM with sticky pad (Group P), and TegadermTM with Steri-StripTM (Group S). Measured variables included parity, gestational age, body mass index (BMI), level of puncture and distance of epidural catheter migration. RESULTS: There was an overall difference in epidural catheter migration (ECM) distance among different groups (p<0.05). Pairwise comparison revealed only a significant difference between groups P and T (0.76±1.35 vs. -0.14±1.03, p<0.01). CONCLUSION: Taping the lumbar epidural catheter used for labor analgesia with TegadermTM is inferior to TegadermTM with sticky pad or with Steri-StripTM in terms of catheter migration. There is no association of catheter migration and BMI.

Objetivo: Comparar el efecto de tres diferentes tipos de fijación sobre la migración del catéter epidural durante el trabajo de parto. Introducción: El fallo del bloqueo epidural en el trabajo de parto se debe a múltiples factores incluyendo la migración de catéter. La migración de catéter epidural se ha relacionado con el índice de masa corporal y la posición, así como con movimientos del paciente. La técnica de fijación también afecta la migración de catéter y el riesgo de bloqueo epidural fallido. Método: Las pacientes fueron aleatorizadas y asignadas a uno de tres grupos según el tipo de fijación: TegadermTM (Grupo T), TegadermTM con almohadilla adhesiva (Grupo P) y Tegaderm TM con Steri-StripTM (Grupo S). Las variables evaluadas incluyeron paridad, edad gestacional, índice de masa corporal (IMC), nivel de punción y distancia de migración del catéter epidural. Resultados: Se detectó una diferencia en la distancia de migración de catéter epidural entre los diferentes grupos (p<0.05). La comparación reveló diferencia únicamente entre los grupos P y T (0.76±1.35 vs. -0.14±1.03, p<0.01). Conclusión: TegadermTM como método de fijación de catéter epidural en el trabajo de parto resultó ser inferior al TegadermTM con almohadilla adhesiva o con Steri-StripTM en términos de migración de catéter. No existe una asociación entre migración de catéter epidural e IMC.

Reducing breakthrough pain during labour epidural analgesia: an update.

PURPOSE OF REVIEW: Neuraxial techniques are the current gold standard for labour analgesia, but are associated with up to 25% incidence of breakthrough pain. In this review, we aim to update clinicians on the latest research pertaining to the optimization of neuraxial labour analgesia. RECENT FINDINGS: Attempts to improve the efficacy and reliability of epidural analgesia while minimizing adverse effects have resulted in the rising popularity of combined spinal epidural and the dural puncture epidural (DPE). Recent studies have focused on determining the safety, efficacy, and optimization of the DPE technique.Another research focus is on the development of individualized therapy in which patients may titrate their own labour analgesia according to their varying requirements, possibly augmented with computer-aided feedback systems and automated mandatory bolus techniques that automatically adjust drug delivery to the patients' analgesic requirements. The addition of a risk-stratification model based on maternal, anaesthetic, and obstetric factors will facilitate early institution of individualized therapy to forestall breakthrough pain in higher risk patients. SUMMARY: Recent advances in combined spinal epidural, DPE, automated mandatory bolus, and individualized therapies have advanced our goal of providing effective labour analgesia that is titrated to changing analgesic requirements during labour and delivery and reducing breakthrough pain.

Randomized comparison of two methods of the epidural space identification during regional labour analgesia.

OBJECTIVES: Conventional loss of resistance (LOR) technique for identifying the epidural space (EDS) predominantly depends on experience of the anaesthetist. A technique using automated syringe for EDS identification was invented as an alternative to the traditional method. The aim of the study was to compare the efficacy and risk for complications between automatic LOR syringe - Epimatic® (Vygon, Ecouen, France) and conventional LOR - Perifix® (B.Braun Melsungen AG, Melsungen, Germany) techniques for EDS identification. MATERIAL AND METHODS: A total of 170 patients were enrolled into the study and 153 cases were analysed. Number of at- tempts, time to EDS identification, ease of EDS identification, complication rate and patient procedure-related discomfort were evaluated and compared. RESULTS: No statistically significant differences were found in the number of needle insertion attempts (1.3 in both groups), time to EDS identification (31 sec. vs. 27 sec.), efficacy of epidural analgesia (100% in both groups), or complication rate between both groups. CONCLUSIONS: The automatic and the conventional LOR techniques are comparable in terms of efficacy and safety for the epidural space identification.

Epidural test dose in obstetric patients: should we still use it?

PURPOSE OF REVIEW: As the application of a test dose after epidural catheter insertion in obstetrics has recurrently been associated with serious adverse events affecting both maternal and foetal outcomes, the question whether to test or not remains a controversial issue. RECENT FINDINGS: Present guidelines do not provide clear recommendations in this regard and several recent surveys indicate a heterogeneity in clinical routine. SUMMARY: Physiological alterations during pregnancy and labour restrict the use and also the validity of traditional test agents. Epinephrine is not appropriate to detect a vascular insertion in labour and the application of a local anaesthetic test dose may lead to dose-dependent fatal consequences should the catheter be intrathecal, due to an increased sensitivity in parturients. Given the current practice of opioid-amended-low-concentration epidurals, the waiving of a test dose results at worst in a failed epidural, a stark contrast to the potentially severe to fatal complications of a 'traditional' test dose. Hence, an originally preventive measure providing potentially more harm than the consequences of the situation aimed to prevent, should not be recommended. A simple fractionated administration of the initial analgesic dose seems reasonable though.

Birthing ball versus pethidine and haloperidol in satisfaction with childbirth. / Pelota de parto versus petidina y haloperidol en la satisfacción en el parto.

OBJECTIVE: To determine the effects on maternal satisfaction of the use of the birthing ball as a method of pain relief compared to the subcutaneous administration of pethidine (50mg) and haloperidol (2.5mg), during the latent phase of labour. METHOD: Randomised, unicentric, parallel and controlled clinical trial. PARTICIPANTS: Low-risk pregnant women hospitalised in a pathological pregnancy ward at the Gregorio Marañón University General Hospital (Madrid) due to prolonged pregnancy, premature rupture of membranes, or labour prodromes. INTERVENTION: once the patient's labour had become painful, a series of pre-established movements were implemented with a birthing ball in the intervention group, or pethidine and haloperidol were administered at the same dose subcutaneously. After the intervention and on the post-natal ward, satisfaction was measured with the Mackey Satisfaction Childbirth scale, validated in Spanish in 2016, in the first 48-72hours after delivery. ANALYSIS: group comparisons: Student's t for continuous variables and Chi-squared for categorical variables. Significance at p<0.05. RESULTS: The maternal satisfaction was significantly higher in the experimental group than in the comparison group, in all the domains of the scale: obstetrician (4.24/3.87), dilatation (4.02/3.35), second stage (4.27/3.67), newborn (4.72/4.43), accompaniment and comfort (4.78/4.44). There were, however, no statistically significant differences in the midwife subscale, although the scores were equally high (4.65/4.45). CONCLUSION: Using birthing balls during the latent phase of labour increases women's satisfaction with their labour process more than administering pethidine and haloperidol during this period.

Electric stimulation-guided epidural analgesia for vaginal delivery: A randomized prospective study.

BACKGROUND: The failure rate of epidural anesthesia using the loss of resistance technique is 13-23%. OBJECTIVES: To investigate the efficacy of epidural electric stimulation-guided epidural analgesia in vaginal delivery. STUDY DESIGN: An open label randomized prospective study. METHODS: Laboring women were randomized to two groups: epidural catheter insertion using only a loss of resistance technique or a loss of resistance technique with confirmation by electric stimulation. Catheters in both groups were initially tested with 3 ml of 1% lidocaine and those with any evidence of motor blockade were considered intrathecal. Sensory blockade and an 11 point numerical rating score for pain were assessed 30 minutes after administration of an epidural bolus of 10 ml of 0.22% ropivacaine with fentanyl. Successful epidural analgesia was defined as a decrease of 2 or more in the pain score and a bilateral L1-T10 sensory blockade. RESULTS: Thirty-one patients were randomized to each group. The first 20 patients in each group were enrolled in a pilot study and were also included in the final analysis. One patient in the electric stimulation group was excluded owing to dural puncture by the Tuohy needle. One patient in each group demonstrated motor blockade after test dose and were considered failures. The number (% (95% confidence interval)) of successful cases were 29 out of 30 (97% (85, 100%)) in the electric stimulation group and 24 out of 31 (77% (61, 89%)) in the loss of resistance group (P = 0.053). However, analysis of only patients with absence of motor blockade revealed that 29 out of 29 (100% (92, 100%)) patients in the electric stimulation group and 24 of 29 (80% (63, 91%)) patients in the loss of resistance group had adequate analgesia (P = 0.024). CONCLUSIONS: Although limited by lack of blinding, small study size and inclusion of pilot study data, this study suggests epidural electric stimulation improves the success rate of subsequent labor analgesia.

Ultrasound guided L5-S1 placement of labor epidural does not improve dermatomal block in parturients.

BACKGROUND: Based on their experience or training, anesthesiologists typically use the iliac crest as a landmark to choose the L3-4 or L2-3 interspace for labor epidural catheter placement. There is no evidence-based recommendation to guide the exact placement. We hypothesized that lower placement of the catheter would lead to a higher incidence of S2 dermatomal block and improved analgesia in late labor and at delivery. METHODS: One-hundred parturients requesting epidural analgesia were randomly assigned to receive ultrasound-guided L5-S1 epidural catheter placement (experimental group) or non-ultrasound-guided higher lumbar interspace placement (control group). The primary outcome was the incidence of S2 block 30 minutes after administering 10 mL 0.125% bupivacaine. Secondary outcomes were average pain throughout labor and maximum pain during labor or during delivery. RESULTS: Forty-nine subjects were enrolled in control group and 47 in the experimental group. The primary endpoint did not significantly differ between groups (control group 81% vs experimental group 91%, P=0.24). The secondary endpoints were not significantly different: pain relief after 30 minutes (mean pain score 1.4 in the control group vs 1.9 in the experimental group, P=0.2) and pain at delivery (mean score 4 in the control group vs 3.9 in the experimental group, P=0.6). CONCLUSION: Placement of an epidural catheter at the L5-S1 interspace using ultrasound did not improve sacral sensory block coverage when compared with an epidural catheter placed at a higher lumbar interspace, without using ultrasound guidance.

Color your epidural: color flow Doppler to confirm labor epidural needle position.

BACKGROUND: Labor epidural analgesia success depends on precise needle position placement within the epidural space, with reported failure rates to be as high as 32%. In this study, we describe a novel technique employing color Doppler to aid in the confirmation of the correct position of the epidural needle tip. METHODS: Retrospective evaluation of 35 patients who received labor combined spinal-epidural (CSE) with confirmation of epidural needle position with color flow Doppler (CFD) ultrasonography. Demographic data, intervertebral level of insertion and dermatome sensory level were extracted. Video and image evaluation of CFD patterns were used to confirm epidural needle tip and catheter position. CFD was used to visualize intrathecal injection of local anesthetic in two patients. RESULTS: Three different color flow patterns were visualized after the loss of resistance technique: visualization of a red and blue mosaic adjacent to the posterior complex, a mosaic pattern enveloping the trajectory of the epidural needle, and a linear deeper mosaic color pattern during spinal injection in relation to the posterior complex. Identification of epidural needle tip and epidural catheter tip occurred in 77% and 37.1% of patients, respectively. CONCLUSIONS: CFD is a novel and useful technique to confirm the precise position of the epidural needle tip in the context of labor analgesia. Identification of the epidural catheter with CFD is difficult despite an adequate CSE technique.

A systematic review of DURAL puncture epidural analgesia for labor.

STUDY OBJECTIVE: This systematic review aimed to summarize the evidence derived from randomized controlled trials (RCTs) comparing dural puncture epidural analgesia (DPEA) and conventional lumbar epidural analgesia (LEA) for women undergoing labor. INTERVENTIONS: The MEDLINE and EMBASE databases were searched from inception to July 2018 in order to find RCTs published in the English language, which investigated DPEA in laboring women. MAIN RESULTS: Six RCTs were included in the final analysis. Their collective results remain ambiguous. Dural puncture with small (i.e., 26- or 27-gauge) spinal needles seems to confer either minimal benefits or improved analgesic quality and lower pain scores in the first 10 min. Dural puncture with 25-gauge spinal needles has been reported to provide higher success rate than conventional LEA in one trial; however two other studies could only agree on the fact that DPEA results in improved sacral blockade and fewer unilateral blocks compared to LEA. CONCLUSIONS: The current evidence regarding DPEA for labor analgesia remains ambiguous. Future research should investigate the optimal (spinal) needle size for dural puncture as well as factors governing transmeningeal flux of local anesthetics and opioids in the presence of a dural hole.

Development and validation of a predictive risk factor model for epidural re-siting in women undergoing labour epidural analgesia: a retrospective cohort study.

BACKGROUND: Epidural catheter re-siting in parturients receiving labour epidural analgesia is distressing to the parturient and places them at increased complications from a repeat procedure. The aim of this study was to develop and validate a clinical risk factor model to predict the incidence of epidural catheter re-siting in labour analgesia. METHODS: The data from parturients that received labour epidural analgesia in our centre during 2014-2015 was used to develop a predictive model for epidural catheter re-siting during labour analgesia. Multivariate logistic regression analysis was used to identify factors that were predictive of epidural catheter re-siting. The forward, backward and stepwise variable selection methods were applied to build a predictive model, which was internally validated. The final multivariate model was externally validated with the data collected from 10,170 parturients during 2012-2013 in our centre. RESULTS: Ninety-three (0.88%) parturients in 2014-2015 required re-siting of their epidural catheter. The training data set included 7439 paturients in 2014-2015. A higher incidence of breakthrough pain (OR = 4.42), increasing age (OR = 1.07), an increased pain score post-epidural catheter insertion (OR = 1.35) and problems such as inability to obtain cerebrospinal fluid in combined spinal epidural technique (OR = 2.06) and venous puncture (OR = 1.70) were found to be significantly predictive of epidural catheter re-siting, while spontaneous onset of labour (OR = 0.31) was found to be protective. The predictive model was validated internally on a further 3189 paturients from the data of 2014-2015 and externally on 10,170 paturients from the data of 2012-2013. Predictive accuracy of the model based on C-statistic were 0.89 (0.86, 0.93) and 0.92 (0.88, 0.97) for training and internal validation data respectively. Similarly, predictive accuracy in terms of C-statistic was 0.89 (0.86, 0.92) based on 2012-2013 data. CONCLUSION: Our predictive model of epidural re-siting in parturients receiving labour epidural analgesia could provide timely identification of high-risk paturients required epidural re-siting.

Experimental validation of the CompuFlo® epidural controlled system to identify the epidural space and its clinical use in difficult obstetric cases.

BACKGROUND: This prospective study was designed to validate the CompuFlo® device and to assess its use in difficult epidural placement. METHODS: In the first part of the study, 30 parturients requesting labor epidural analgesia were recruited. The block was performed by an expert anesthesiologist, with the Tuohy needle connected to the CompuFlo® device to evaluate the agreement between the anesthesiologist's reported sensation and the variation of pressure recorded by the CompuFlo®. In the second part of the study, 56 consecutive parturients, for whom at least two complete needle reinsertions were made by trainees during epidural placement for labor analgesia, were enrolled. CompuFlo® was used as a rescue tool for the subsequent attempt. RESULTS: In all cases epidural analgesia was successful and no complications were noted. There was a good correlation between the operator's feelings and the delta of pressure recorded by the CompuFlo®, for both identification of the ligamentum flavum and of the epidural space (Rho = 0.79; tau = 0.67). In the second part of the study, all the difficult blocks performed with the CompuFlo® were successful after a single attempt. The pressure curves of false loss-of-resistance were significantly different from the true loss-of-resistance (P <0.0001) DISCUSSION: CompuFlo® was validated as a tool to identify the epidural space. It may also assist trainees in successful epidural placement in difficult cases.