A pilot study to compare epidural identification and catheterization using a saline-filled syringe versus a continuous hydrostatic pressure system

Real-time ultrasound-guided mid-thoracic epidural access using a novel paramedian cross (PX) view and drip infusion technique: a brief technical report

BACKGROUND

Real-time ultrasound guidance (USG) has been applied for lower thoracic epidural access, but the more challenging mid-thoracic epidural (MTE) access remains underexplored. This report presents a technique of real-time US guidance with a novel paramedian cross view, termed "the PX view," for securing MTE catheters, along with an outcome analysis from a retrospective case series.

METHODS

Medical records of patients who underwent USG-MTE catheter placement with the PX view and drip infusion technique from January to December 2022 were reviewed. All catheters were placed with patients in the prone position under mild to moderate procedural sedation. The process of acquiring the PX view, in-plane needling technique, and the use of drip infusion to identify loss of resistance were detailed. The incidence of successful PX view attainment, the number of attempts, redirections, failures, and any technique-related complications were recorded.

RESULTS

Fifty-one patients underwent USG-MTE catheter attempts, (42 with median sternotomy, 3 fractured ribs, 3 upper abdominal laparotomies, 2 modified radical mastectomies, and 1 thoracotomy). A satisfactory PX view was obtained in all patients, and the epidural space was identified during the first needle entry in 49 cases, resulting in a 96% first-attempt success rate. Seven patients required needle redirections, while two patients needed a second needle entry. No technique-related complications were documented.

CONCLUSION

The combination of the PX view and the drip infusion method proved effective for real-time ultrasound-guided MTE catheter placement.

Localization of epidural space: A review of available technologies

Although epidural analgesia is widely used for pain relief, it is associated with a significant failure rate. Loss of resistance technique, tactile feedback from the needle, and surface landmarks are traditionally used to guide the epidural needle tip into the epidural space (EDS). The aim of this narrative review is to critically appraise new and emerging technologies for identification of EDS and their potential role in the future. The PubMed, Cochrane Central Register of Controlled Clinical Studies, and Web of Science databases were searched using predecided search strategies, yielding 1048 results. After careful review of abstracts and full texts, 42 articles were selected to be included. Newer techniques for localization of EDS can be broadly classified into techniques that (1) guide the needle to the EDS, (2) identify needle entry into the EDS, and (3) confirm catheter location in EDS. An ideal method should be easy to learn and perform, easily reproducible with high sensitivity and specificity, identifies inadvertent intrathecal and intravascular catheter placements with ease, feasible in perioperative setting and have a cost-benefit advantage. Though none of them in their current stages of development qualify as an ideal method, many show tremendous potential. Some techniques are useful in patients with difficult spinal anatomy and infants, and thus are complementary to traditional methods. In addition to improving the existing technology, future research should aim at proving the superiority of these techniques over traditional methods, specifically regarding successful EDS localization, better safety profile, and a favorable cost-benefit ratio.

A proposal of a simple epidural simulator for training novice anesthesiologists

PURPOSE

Confirming the epidural space during epidural anesthesia relies mainly on feel and experience, which are difficult techniques for a trainee to learn. We designed an epidural simulator for trainees to experience loss of resistance (LOR) and various degrees of pressure resistance.

METHODS

The simulator consists of a Perifix(®) LOR syringe and 1-, 5-, 10- and 50-mL syringes assembled by three-way stopcocks. A total of 89 anesthesiologists evaluated the simulator, given the choice of either the intermittent technique with air or continuous technique with saline. Sudden LOR and applicability of the simulator for training purposes were assessed using the numerical rating score (NRS). Pressure resistance at each lumbar structure was evaluated by the anesthesiologists using the intermittent technique with air.

RESULTS

Seventy-four anesthesiologists used the intermittent technique with air and 15 used the continuous technique with saline. The NRSs for sudden LOR and the applicability for training purposes were 8 and 9 (median), respectively. The pressure resistance to a 50-mL syringe was regarded as the epidural space (odds ratio 602.3 for 5-mL syringe and 144.4 for 10-mL syringe) by 89 % of anesthesiologists using air for LOR. Resistance to the 10-mL syringe was most frequently considered as muscle, subcutaneous fat, or the interspinous ligament, while resistance to the 1-mL syringe was considered as the ligamentum flavum (odds ratio 2.3 for 5-mL syringe and 18.6 for 10-mL syringe).

CONCLUSIONS

Our epidural simulator is a simple, low-cost device that can be easily constructed. It was shown to provide valid haptic feedback as a promising tool for training novice anesthesiologists.