From the Department of Anesthesiology, Pain Management, and Perioperative Medicine, Henry Ford Health, Detroit, Michigan.
Department of Biomedical Engineering, Wayne State University, Detroit, Michigan.
Anesth Analg. 2023 Jun 1;136(6):1198-1205. doi: 10.1213/ANE.0000000000006268. Epub 2022 Oct 26.
The programmable intermittent epidural bolus (PIEB) has been popularized as the optimal delivery technique for labor analgesia. Suggested advantages of this method are less local anesthetic consumption, improved maternal satisfaction, potentially shorter duration of labor, and decreased workload requirements for the anesthesia providers. However, a manual bolus is still routinely used for breakthrough pain when the PIEB is underperforming.
We conducted a laboratory-based study to quantify the flow through a multiorifice epidural catheter using the PIEB setting on an epidural pump compared to the manual epidural bolus. Four syringe volumes, 3, 5, 10, and 20 mL, were selected for this experiment. The flow in a manual bolus was also studied with and without the presence of an epidural catheter filter. A generalized estimating equation analysis was done to compare data between the groups.
Regardless of the syringe size, there was a several-fold increase in flow when a manual bolus was used compared to a pump-administered dose, with the highest difference in the peak flow rate observed in 3-mL boluses with up to a 12-fold difference, while the difference was, at most, 7-fold in 5-mL and 10-mL boluses. Manual boluses without a filter achieve a mean peak flow rate higher than manual boluses with a filter.
Our study found that manual boluses produced a higher flow rate compared to the CADD-Solis epidural pump (Smiths Medical). This study also found that the placement of a particulate filter reduces the flow rates generated while bolusing. Bulk flow rate is directly correlated with induced pressure and solution spread. Because higher bolus pressure has been shown to provide a more efficient distribution of local anesthetic and more efficient pain relief, these results may have impactful clinical significance and will pave the way for future studies.
可编程间歇性硬膜外推注（PIEB）已被推广为分娩镇痛的最佳输送技术。这种方法的优点是局部麻醉剂用量减少，产妇满意度提高，分娩时间可能缩短，麻醉提供者的工作量要求降低。然而，当 PIEB 性能不佳时，仍会常规使用手动推注来缓解突破性疼痛。
我们进行了一项实验室研究，使用硬膜外泵上的 PIEB 设置来量化多侧孔硬膜外导管的流量，与手动硬膜外推注进行比较。本实验选择了 3、5、10 和 20 毫升四个注射器体积。还研究了手动推注在有无硬膜外导管过滤器的情况下的流量。使用广义估计方程分析比较了组间数据。
无论注射器大小如何，与泵给药剂量相比，使用手动推注时流量都会增加几倍，在 3 毫升推注中观察到最高峰值流速差异最大，可达 12 倍，而在 5 毫升和 10 毫升推注中最大差异最多为 7 倍。无过滤器的手动推注的平均峰值流速高于带过滤器的手动推注。
我们的研究发现，与 CADD-Solis 硬膜外泵（Smiths Medical）相比，手动推注产生的流量更高。本研究还发现，放置颗粒过滤器会降低推注时产生的流量。体积流量与诱导压力和溶液扩散直接相关。由于较高的推注压力已被证明可以更有效地分布局部麻醉剂并提供更有效的疼痛缓解，因此这些结果可能具有重要的临床意义，并为未来的研究铺平道路。
