An in vitro evaluation of flow from multihole epidural catheters during continuous infusion with four different infusion pumps

Challenges with two epidural catheters for labor analgesia in a patient with lumbar adhesions: a case report

BACKGROUND

The efficacy of neuraxial analgesia varies with spinal canal pathology. Notably, a secondary epidural catheter has been shown to increase neuraxial labor analgesia in women with spinal lesions. Therefore, we present a case in which catheter withdrawal played a critical role in achieving effective labor analgesia in a woman with epidural adhesions after lumbar discectomy who had inadequate analgesia with two epidural catheters.

CASE PRESENTATION

We encountered a patient with L5 lumbar epidural adhesions who reported pain even after receiving two epidural catheters. The catheters were placed in the L1/2 and L5/S intervertebral spaces. Analgesic effects were exerted when the L5/S catheter was withdrawn by 1 cm, suggesting that the catheter tip was initially placed inside the adhesion.

CONCLUSIONS

Careful consideration of catheter placement and adjustments by withdrawing the catheter are crucial in managing labor analgesia in patients with known epidural adhesions.

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.

Variability of performance of wound infusion catheters

OBJECTIVE

To compare the distribution of flow from two commercial and one handmade multihole wound infusion catheters.

STUDY DESIGN

Open label experimental measurement of flow distribution in a bench top apparatus of handmade (n = 10) and two commercial (n = 10 each) wound infusion catheters with 5-6'' (12-15.2 cm) long diffusion surfaces.

METHODS

The distribution of 6 mL of distilled water injected at three different injection speeds (0.5, 5, and 120 minutes) through individual triangular pieces of felt cloth fitted over six contiguous regions of the diffusion surface of each catheter was measured in triplicate.

RESULTS

The distribution of flow through the six regions was significantly more uniform at the two faster injection speeds. Ninety two per cent of the 120 minute infusion trials resulted in one or more regions producing negligible flow (<5% of total output), and in 16% of the 120 minute trials all the flow came from just one or two regions.

CONCLUSIONS

Constant-rate infusions of 3 mL hour(-1) provide erratic distribution of flow from wound infusion catheters in a bench top apparatus. Commercial catheters did not outperform handmade catheters.

CLINICAL RELEVANCE

Uneven distribution of flow at low infusion speeds may contribute to inconsistent or unsatisfactory pain relief in patients treated with continuous wound infusions of local anesthetics.

Protocols to compare infusion distribution of wound catheters

Multi-holed wound catheters are increasingly used in clinical practice to administer analgesic/anaesthetic locally to the painful region. The distribution of flow infused during controlled (continuous or intermittent) administration of medication is believed to be an important issue for successful pain relief. Nevertheless, this information is not available from the literature. In this paper, we propose protocols to screen the performance of wound infusion catheters in the laboratory environment. Four wound infusion systems (PAINfusor by Baxter, OnQ Pump with Soaker catheter by I-Flow, PolyFuser Polymedic by Temena and Infiltralong by Pajunk) have been tested. Test results demonstrate that the distribution of the infused flow is different for the four catheters and closely connected to the catheter design (i.e. hole size and position, lumen diameter). Catheters characterized by small size holes (e.g. Baxter, Pajunk) distribute the flow more homogeneously than catheters characterized by large size holes (e.g. I-Flow, Temena). The distribution of infused flow does not change significantly during continuous or intermittent infusion.

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.