Superiority of multi-orifice over single-orifice epidural catheters for labor analgesia and cesarean delivery

Comparison of labor analgesia efficacy between single-orifice and multiorifice wire-reinforced catheters during programmed intermittent epidural boluses: a randomized controlled clinical trial

AIMS

We compared analgesic outcomes between single-orifice and multiorifice wire-reinforced catheters under 480 mL/hour delivery rate with programmed intermittent epidural bolus administration.

METHODS

Between August and November 2021, 182 nulliparous and healthy women with singleton pregnancy, 2-5 cm cervical dilation, and requesting neuraxial analgesia were randomized to receive either single-orifice or multiorifice catheters. Epidural analgesia was initiated and maintained with 0.1% ropivacaine and 0.3 µg/mL sufentanil. Programmed intermittent epidural bolus volume of 10 mL was administered every 45 min at 480 mL/hour beginning immediately after the test dose. Primary outcome was the percentage of parturients in the two groups with adequate analgesia 20 min after the initial bolus.

RESULTS

Compared with multiorifice catheters, single-orifice catheters were associated with a higher proportion of parturients with adequate analgesia (71.8% vs 56.0%, respectively; 95% CI 1.3% to 29%, p=0.03) and more frequent S₂ sensory blockade (37.6% vs 22.6%, respectively; 95% CI -30% to 1%, p=0.03) 20 min after block initiation. Median time (IQR) to adequate analgesia was 12 (8-30) min and 20 (10-47) min with single-orifice and multiorifice catheters, respectively (95% CI 0.1 to 0.7 min, p<0.01). The median (IQR) ropivacaine consumption per hour was higher in parturients receiving multiorifice catheters than those with single-orifice catheters (15.3 (13.3-17.0) mg/hour vs 13.3 (13.3-15.4) mg/hour, respectively; 95% CI 0.2 to 0.8 mg/hour, p<0.001).

CONCLUSION

Single-orifice catheters used for programmed intermittent epidural bolus at 480 mL/hour for epidural labor analgesia had improved analgesic efficacy than multiorifice catheters.

TRIAL REGISTRATION NUMBER

ChiCTR2100049872.

Regional Anaesthetic Techniques and Their Implications During the COVID Pandemic

The current pandemic has highlighted the need to protect both patients and medical staff. The increased use of regional anaesthesia as a primary anaesthetic modality for operations and other invasive procedures has limited the number of aerosol-generating procedures performed during general anaesthesia. Its use is further characterized by decreases in postoperative pain and length of hospitalization. This article provides an overview of regional anaesthetic techniques (peripheral nerve locks, epidural and spinal anaesthesia) and their uses during the COVID pandemic.

Epidural catheter design: history, innovations, and clinical implications

Epidural catheters have evolved during the past several decades, as clinicians and manufacturers have sought to influence the quality of analgesia and anesthesia and reduce the incidence of catheter-related complications. This evolution has allowed a transformation from single-shot to continuous-infusion techniques and resulted in easier passage into the epidural space, more extensive medication distribution, and ultimately, improved patient satisfaction. Particular catheter features, including the materials used, tip design, and orifice number and arrangement, have been associated with specific outcomes and provide direction for future development.

[Failure of extension of epidural analgesia to anesthesia for emergency cesarean section]

Epidural analgesia provides effective control of labor pain and allows emergency cesarean section to be performed without recourse to general anesthesia. This technique is subject to failure, however. We sought to determine the incidence of failure of extension of epidural analgesia for labor to epidural anesthesia for emergency cesarean section. We also analyzed possible risk factors for failure. A 2-month observational study was carried out in a tertiary-care university hospital in patients who had an epidural catheter inserted for labor analgesia and who later underwent emergency cesarean section. Epidural catheter failure was defined if additional analgesia was required during surgery or if general anesthesia was required. Data were gathered on possible risk factors, such as obesity, difficult epidural puncture, leakage of blood on insertion, history of cesarean delivery, need for rescue analgesia, and level of satisfaction with analgesia during dilation. In total, 134 emergency cesareans were performed in women carrying an epidural catheter. The catheter failed to administer the anesthetic in 18 patients (13.4%). General anesthesia was required in 9 cases (6.7%). Difficult insertion (more than 2 attempts) was associated with a higher failure rate (P=.064). The relative risk of epidural catheter failure was 2.86-fold higher when rescue analgesia was needed during delivery than in cases when no supplement was required (P=.021). Receiving adequate analgesia during labor seems to be a protective factor (80%) against anesthetic catheter failure during cesarean section (P=.01). We conclude that high demand for rescue analgesia and signs of inadequate analgesia during labor should warn of epidural catheter failure if extension to anesthesia becomes necessary for a cesarean delivery.

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.

A systematic review of randomized controlled trials that evaluate strategies to avoid epidural vein cannulation during obstetric epidural catheter placement

BACKGROUND

In this systematic review, we evaluated the evidence for seven strategies which have been proposed to minimize the incidence of epidural vein cannulation during lumbar epidural catheter placement in pregnant women.

METHODS

Multiple databases were searched to identify prospective, randomized, controlled trials between December 1966 and October 2007 that evaluated methods to avoid epidural vein cannulation after lumbar epidural catheter placement in pregnant women. Published trials were evaluated using a quality assessment tool, and results were combined to evaluate efficacy to prevent epidural vein cannulation.

RESULTS

Of 90 trials screened, 30 trials were included (n = 12,738 subjects). Five strategies reduce the risk of epidural vein cannulation: the lateral as opposed to sitting position (six trials, mean (sd) quality score = 35% [11%], odds ratio (OR) 0.53 [95% confidence interval (CI) 0.32-0.86]), fluid administered through the epidural needle before catheter insertion (8 trials, quality score 48% [18%], OR 0.49 [95% CI 0.25-0.97]), single rather than multiorifice catheter (5 trials, quality score 30% [6%], OR 0.64 [95% CI 0.45-0.91]), a wire-embedded polyurethane compared with polyamide epidural catheter (1 trial, 31%, plus 4 unscored abstracts, OR 0.14 [95% CI 0.06-0.30]) and catheter insertion depth < or =6 cm (2 trials, 47% [11%], OR 0.27 [95% CI 0.10-0.74]). The paramedian as opposed to midline needle approach and smaller epidural needle or catheter gauges do not reduce the risk of epidural vein cannulation.

CONCLUSION

The risk of intravascular placement of a lumbar epidural catheter in pregnancy may be reduced with the lateral patient position, fluid predistension, a single orifice catheter, a wire-embedded polyurethane epidural catheter and limiting the depth of catheter insertion to 6 cm or less. In general, low manuscript quality weakens the strength of these conclusions.

Incidence and characteristics of failures in obstetric neuraxial analgesia and anesthesia: a retrospective analysis of 19,259 deliveries

A retrospective analysis was performed on 19,259 deliveries that occurred in our institution from January 2000 to December 2002. Anesthesia records and quality assurance data sheets were reviewed for the characteristics and failure rates of neuraxial blocks performed for labor analgesia and anesthesia. The neuraxial labor analgesia rate was 75% and the overall failure rate was 12%. After adequate analgesia from initial placement, 6.8% of patients had subsequent inadequate analgesia during labor that required epidural catheter replacement. Ultimately 98.8% of all patients received adequate analgesia even though 1.5% of patients had multiple replacements. Six percent of epidural catheters had initial intravenous placement but 46% were made functional by simple manipulations without higher subsequent failure. Unintended dural puncture occurred in 1.2% of labor neuraxial analgesia. The incidences of overall failure, intravenous epidural catheter, wet tap, inadequate epidural analgesia and catheter replacement were lower in patients receiving combined spinal-epidural versus epidural analgesia. For cesarean section, 7.1% of pre-existing labor epidural catheters failed and 4.3% of patients required conversion to general anesthesia. Spinal anesthesia for cesarean section had a lower failure rate of 2.7%, with 1.2% of the patients requiring general anesthesia. The overall use of general anesthesia decreased from 8% to 4.3% over the three-year period. Furthermore, regional anesthesia was used in 93.5% of cesarean deliveries with no anesthetic-related mortalities. Future investigations should identify acceptable international standards, risk factors associated with failure and methods to reduce failure before cesarean section.

Mechanisms and management of an incomplete epidural block for cesarean section

Epidural blockade is an important option for anesthesia in parturients undergoing abdominal delivery. Despite the multiple benefits of this method, there is at least one significant downside--a relatively high occurrence of unsatisfactory anesthesia that requires intervention. Depending on the presumed mechanism of epidural block failure and other clinically relevant factors (e.g., timing of diagnosis, urgency of the procedure, and so forth), certain effective measures are recommended to successfully manage this demanding situation. In general, it is important to make every effort to make the pre-existing epidural effective or replace it with another regional technique, because overall, regional anesthesia is associated with significantly lower maternal mortality. It is important to identify a dysfunctional epidural block preoperatively before a maximum volume of local anesthetic has been administered. If catheter manipulation does not produce substantial improvement, and there is no time constraint, it is safe and reasonable to replace the epidural catheter. However, risks associated with excessive volume of local anesthetic should be kept in mind. Additional epidural injections or a second catheter placement might be considered under special circumstances. Single-shot spinal anesthesia after a failed epidural may provide fast onset and reliable surgical anesthesia. Available data, although limited and contradictory, suggest the possibility of unpredictably high or total spinal anesthesia. Many authors, however, believe that appropriate precautions and modifications in technique make this a safe alternative. These modifications include limiting the amount of epidural local anesthetic administered when diagnosing a nonfunctioning epidural and decreasing the dose of intrathecal local anesthetic by 20% to 30%. If there is no documented block when the spinal is inserted, and more than 30 minutes have passed from the last epidural dose, it is probably safe to use a normal dose of local anesthetic. Continuous spinal anesthesia with a macro catheter might be a dependable alternative, particularly if large amounts of local anesthetic have already been used or the patient's airway is a cause for concern. Although there are no reports of combined spinal epidural anesthesia being used in this context, it would appear to be an attractive alternative. It allows the anesthesiologist to give smaller doses intrathecally, while still offering the flexibility of augmenting the block if needed. When inadequate epidural block becomes apparent during surgery there are limited alternatives. Depending on the origin and the pattern of inadequate anesthesia, options may include psychological support, supplementation with a variety of inhalational and intravenous agents, and local anesthetic infiltration. Induction of general anesthesia is typically left as a backup option, but must be strongly considered if the patient continues to have pain/discomfort.

[Is obstetric epidural anaesthesia technically possible after spinal surgery and does it work?]

OBJECTIVE

Previous spine surgery theoretically exposes the obstetric patient to a greater technical difficulty during regional analgesia for labour or during anaesthesia for caesarean delivery. Published experience suggests that epidural puncture is however technically possible in the majority of cases.

STUDY DESIGN

Retrospective study.

PATIENTS

Analysis of the files of parturients who gave birth in a maternity hospital during a six year period and who had previously undergone spine surgery.

METHODS

Technical failures (during puncture), analgesic failures (complete block inefficiency and/or requirement of a general anaesthetic) and complications (important bleeding at the puncture site, dural tap, infection) observed during epidural analgesia/anaesthesia were recorded.

RESULTS

Except for two paraplegic parturients who had been operated for dorsocervical traumatic injuries and who were excluded from the analysis, 31 parturients had undergone spine surgery and delivered during the period of analysis. Twenty patients underwent 22 epidural punctures. Technical failure were noted in two cases (9%) and analgesic failure in two other cases (9%). No significant complication was recorded.

CONCLUSION

With an overall 18% failure rate, epidural anaesthesia is not contra-indicated in these patients but appears to be less reliable than in patients with normal spine. Psychological and technical preparation to the occurrence of failure is necessary.

New developments in epidural anesthesia and analgesia

Several recent advances in epidural anesthesia and analgesia have been reviewed. Perhaps the most exciting area of anticipated future developments relates to the continued development of novel analgesic agents and new epidural delivery systems. There appears to be some movement toward an increased use of intrathecal or peripheral neural blockade techniques for some clinical situations where epidural anesthesia and analgesia have been previously used; however, the ability to provide anesthesia and analgesia to relatively large areas of the body with a single injection or continuous catheter technique without the associated risks of dural puncture and intrathecal catheter placement will continue to assure epidural anesthesia and analgesia techniques a prominent role in anesthesia and pain management.

Uniport soft-tip, open-ended catheters versus multiport firm-tipped close-ended catheters for epidural labor analgesia: a quality assurance study

STUDY OBJECTIVE

To compare a multiport, firm-tipped, close-ended, epidural catheter (Portex catheter) with a uniport, open-ended, soft-tipped, wire-reinforced catheter (Arrow catheter) in obstetric patients.

STUDY DESIGN

Prospective data collection for intradepartmental quality assurance.

SETTING

Obstetric unit in a tertiary care maternity hospital.

PATIENTS

2612 patients requesting labor analgesia.

INTERVENTIONS

The Arrow catheter was used in 1,352 women and the Portex catheter in 1,260 women.

MEASUREMENTS AND MAIN RESULTS

The incidence of unsatisfactory block were 3.3% and 4.4% with the Arrow and Portex catheters, respectively (p = 0.2). The catheter perforated the dura matter in 0.4% of cases with both catheters. The incidence of epidural venipuncture was 1.1% with the Arrow catheter and 5.7% with the Portex catheter (p = 0.0001). Paresthesias occurred in 6% of cases with the Arrow catheter and 11. 2 % of cases with the Portex catheter (p = 0.0001). Epidural catheter reinsertion was required in fewer patients in the Arrow group than in the Portex group (4.8% vs. 7.1%; p = 0.01).

CONCLUSIONS

In obstetric patients, the softer uniport Arrow catheter produces paresthesias and venipunctures less frequently than the firm multiport Portex catheter.