Use of imaging agent to determine postoperative indwelling epidural catheter position

Primary failure of thoracic epidural analgesia: revisited

Primary failure of thoracic epidural analgesia (TEA) remains an important clinical problem, whose incidence can exceed 20% in teaching centers. Since loss-of-resistance (LOR) constitutes the most popular method to identify the thoracic epidural space, the etiology of primary TEA failure can often be attributed to LOR's low specificity. Interspinous ligamentous cysts, non-fused ligamenta flava, paravertebral muscles, intermuscular planes, and thoracic paravertebral spaces can all result in non-epidural LORs. Fluoroscopy, epidural waveform analysis, electrical stimulation, and ultrasonography have been proposed as confirmatory modalities for LOR.The current evidence derived from randomized trials suggests that fluoroscopy, epidural waveform analysis, and possibly electrical stimulation, could decrease the primary TEA failure to 2%. In contrast, preprocedural ultrasound scanning provides no incremental benefit when compared with conventional LOR. In the hands of experienced operators, real-time ultrasound guidance of the epidural needle has been demonstrated to provide comparable efficacy and efficiency to fluoroscopy.Further research is required to determine the most cost-effective confirmatory modality as well as the best adjuncts for novice operators and for patients with challenging anatomy. Moreover, future trials should elucidate if fluoroscopy and electrical stimulation could potentially decrease the secondary failure rate of TEA, and if a combination of confirmatory modalities could outperform individual ones.

Real-time ultrasound guidance versus fluoroscopic guidance in thoracic epidural catheter placement: a single-center, non-inferiority, randomized, active-controlled trial

INTRODUCTION

Fluoroscopy can improve the success rate of thoracic epidural catheter placement (TECP). Real-time ultrasound (US)-guided TECP was recently introduced and showed a high first-pass success rate. We tested whether real-time US-guided TECP results in a non-inferior first-pass success rate compared with that of fluoroscopy-guided TECP.

METHODS

In this single-center, non-inferiority, randomized trial, the primary outcome was the comparison of the first-pass success rate of TECP between real-time US guidance (US group) and fluoroscopic guidance (fluoroscopy group). Secondary outcomes included time to identifying epidural space, procedure time, total number of needle passes, number of skin punctures, final success, and cross-over success.

RESULTS

We randomly assigned 132 patients to the allocated groups. The difference in the first-pass success rate between the groups did not exceed the non-inferiority margin of 15% (US group: 66.7% vs fluoroscopy group: 68.2%; difference -1.5%, 95% exact CI: -14.9% to 11.9%). The difference in the final success rate also did not differ between the groups (98.5% vs 100.0%; difference -1.5%, 95% exact CI: -4.0% to 1.0%). The time to identifying epidural space (45.6 (34-62) vs 59.0 (42-77) s, p=0.004) and procedure time (39.5 (28-78) vs 112.5 (93-166) s, p<0.001) were significantly shorter in the US group.

CONCLUSIONS

Real-time US guidance provided a non-inferior success rate and shorter time spent on preparation and procedure compared with fluoroscopic guidance in TECP.

TRIAL REGISTRATION NUMBER

KCT0006521.

Analgesic outcomes of tramadol alone and in combination with Butorphanol or Flurbiprofen Axetil after cesarean section: a retrospective study with propensity score matching analysis

BACKGROUND

The Society for Obstetric Anesthesia and Perinatology recommends a multimodal analgesia regimen for cesarean delivery analgesia. This study aimed to compare the analgesic effects of tramadol alone and combined with butorphanol or flurbiprofen axetil after a cesarean section.

METHODS

We performed a retrospective analysis based on the electronic medical records of a teaching hospital in China from January 2018 to January 2020. We collected data on demographic characteristics, anesthesia, analgesia strategy, and pain intensity postoperatively during the first 48 hours. Inadequate postoperative analgesia during this period was defined as an NRS score ≥ 4. We also collected data regarding off-bed activity and intestinal function recovery. Participants were classified into three groups according to analgesia regimens. Groups T, TF, and TB received tramadol, a mixture of tramadol and flurbiprofen axetil, and a combination of tramadol and butorphanol, respectively. Analgesic outcomes were compared using propensity score matching analysis.

RESULTS

Data from 2323 cases of caesarean section were included in the analysis, and 521 pairs were matched in each group according to their propensity score. Compared with group T, The inadequate analgesia on pain at rest and pain at movement was lower in group TF (RR: 0.42, 95% CI: 0.36-0.49, P = 0.001 and RR: 0.58, 95% CI: 0.48-0.69, P < 0.001, respectively),and the incidence of inadequate control of pain at movement was higher in group TB (RR: 1.38, 95% CI: 1.22-1.55, P < 0.001). Additionally, the percentage of off-bed activity at 2 days postoperatively was higher in group TB than in groups TF and T (78.7% vs. 68.5 and 78.7% vs. 64.9%, respectively, P < 0.001). The incidence of intestinal function recovery 2 days after cesarean delivery in group TB was higher than that in group TF (73.3% vs. 66.2%, P = 0.013).

CONCLUSIONS

Combining tramadol and flurbiprofen axetil could enhance the analgesic effect and be safely used for analgesia after a cesarean section. However, combining tramadol and butorphanol may produce an antagonistic effect.

The Importance of Initial Epidurography Prior to Any Drug Administration in Three-Day Adhesiolysis Procedure

Percutaneous epidural adhesiolysis (PEA) is a minimal invasive procedure to relieve sciatalgia caused by post lumbar surgery syndrome (PLSS). Fluoroscopic-guided contrast-epidurography is essential to ensure a safe procedure. We present a case of a 28-year-old male patient who underwent a PEA which was complicated by a dural puncture. We highlight the dangers of such complications and discuss associated risk factors.

Sensitivity and specificity of waveform analysis for assessing postoperative epidural function

STUDY OBJECTIVES

To characterize the accuracy of epidural waveform analysis (EWA) in assessing the functionality of thoracic epidural catheters in the immediate postoperative period (primary objective), and to determine the inter-rater reliability between EWA waveform observers (secondary outcome).

DESIGN

Single center, prospective diagnostic accuracy cohort study.

SETTING

Post-anesthetic care unit of a university teaching hospital.

PATIENTS

84 adult patients undergoing elective thoracic, gynecologic, vascular, urologic, or general surgery with preoperative placement of a thoracic epidural catheter for perioperative analgesia.

INTERVENTIONS

EWA tracings were video recorded in the immediate postoperative period through the epidural catheter in the post-anesthetic care unit.

MEASUREMENTS

Postoperative EWA tracings were compared with clinical assessments of the sensory block to ice produced by epidural local anesthetic in the immediate postoperative period. Additionally, intra-class correlation analysis of agreement between 3 independent (and blinded) EWA waveform observers was carried out.

RESULTS

Among 80 patients with thoracic epidurals who completed the study protocol, 73 demonstrated postoperative functional epidurals with sensory block to ice and 7 demonstrated non-functional epidurals. EWA yielded 65 true positives, 6 true negatives, 8 false negatives, and 1 false positive. Postoperative EWA sensitivity, specificity, positive predictive value and negative predictive value, along with the 95% confidence intervals (CI) were 89% (79-95%), 86% (42-100%), 98% (92-100%), and 43% (18-71%) respectively. Intra-class correlation between waveform assessors was 0.870 (95% CI 0.818-0.910, p < 0.001).

CONCLUSIONS

EWA is useful in assessing the position of thoracic epidural catheters in the immediate postoperative period, demonstrating high sensitivity and specificity as well as robust inter-rater reliability. For patients in whom sensory block to ice cannot be reliably assessed postoperatively, EWA may provide a useful adjunct for assessing epidural functionality.

The impact of fluoroscopic confirmation of thoracic imaging on accuracy of thoracic epidural catheter placement on postoperative pain control

Background

Thoracic epidural analgesia (TEA) provides superior postoperative pain control compared to parenteral opioids after major thoracic and abdominal surgeries. However, some studies with respect to benefits of continuous TEA have shown mixed results. The purpose of this study was to determine the rate of successful TEA catheter insertion into the epidural space using contrast fluoroscopy and the impact of placement location on postoperative analgesia and opioid use.

Patients and methods

After Advocate health care institutional review board approval, we conducted a prospective, open-label, single intervention study on patients undergoing thoracic or upper abdominal surgery. A thoracic paramedian epidural approach and a loss of resistance to saline technique were used to place an epidural catheter above the T11 level and fluoroscopic images with injected contrast were taken to locate the catheter tip in the epidural space.

Results

Twenty-five subjects were included in the study, of which 3 catheters (12%) were not identified as being in the epidural space. We found an average difference of 1.5 vertebral levels between clinical and radiological assessments of catheter tips. Thirteen catheters (52%) were more than 1 vertebral level away from the clinically assessed level. No significant difference was found in the pain scores at 1, 24, and 48 hours after surgery between patients with correct versus incorrect catheter placement. Less opioids were used in the correct catheter placement group at 24 hours (256 morphine milligram equivalent [MME] vs 201 MME) and at 48 hours after surgery (250 MME vs 173 MME), but it was not statistically significant (p=0.149 and p=0.068, respectively).

Conclusion

Improvement in assuring success in the technique for TEA catheter placement following major thoracic or upper abdominal surgery exists, for which contrast-enhanced fluoroscopy might be a promising solution.

Raman Spectroscopy Differentiates Each Tissue from the Skin to the Spinal Cord: A Novel Method for Epidural Needle Placement?

BACKGROUND

Neuraxial anesthesia and epidural steroid injection techniques require precise anatomical targeting to ensure successful and safe analgesia. Previous studies suggest that only some of the tissues encountered during these procedures can be identified by spectroscopic methods, and no previous study has investigated the use of Raman, diffuse reflectance, and fluorescence spectroscopies. The authors hypothesized that real-time needle-tip spectroscopy may aid epidural needle placement and tested the ability of spectroscopy to distinguish each of the tissues in the path of neuraxial needles.

METHODS

For comparison of detection methods, the spectra of individual, dissected ex vivo paravertebral and neuraxial porcine tissues were collected using Raman spectroscopy (RS), diffuse reflectance spectroscopy, and fluorescence spectroscopy. Real-time spectral guidance was tested using a 2-mm inner-diameter fiber-optic probe-in-needle device. Raman spectra were collected during the needle's passage through intact paravertebral and neuraxial porcine tissue and analyzed afterward. The RS tissue signatures were verified as mapping to individual tissue layers using histochemical staining and widefield microscopy.

RESULTS

RS revealed a unique spectrum for all ex vivo paravertebral and neuraxial tissue layers; diffuse reflectance spectroscopy and fluorescence spectroscopy were not distinct for all tissues. Moreover, when accounting for the expected order of tissues, real-time Raman spectra recorded during needle insertion also permitted identification of each paravertebral and neuraxial porcine tissue.

CONCLUSIONS

This study demonstrates that RS can distinguish the tissues encountered during epidural needle insertion. This technology may prove useful during needle placement by providing evidence of its anatomical localization.

Eyes on the needle: Identification and confirmation of the epidural space

Epidural catheters are used to provide effective intraoperative and postoperative analgesia. Standard epidural catheterization techniques rely on palpation of surface anatomy and the experience of the anesthesiologist. Failure to correctly place an epidural catheter can lead to inadequate analgesia and serious complications, such as dural puncture headache. Exciting new devices and techniques are being developed for identification of the epidural space and confirmation of catheter entry. This article reviews and describes the recent research findings. The devices and techniques are categorized into three sections: devices that modify the loss of resistance technique; visual confirmation using the epidural needle; and confirmation of placement of the epidural catheter.

Use of colour Doppler and M-mode ultrasonography to confirm the location of an epidural catheter - a retrospective case series

PURPOSE

Epidural anesthesia and analgesia has a reported failure rate ranging from 13% to 32%. We describe a technique using colour Doppler and M-mode ultrasonography to determine the position of the epidural catheter after placement in adults.

METHODS

This retrospective review included 37 adult patients who received postoperative epidural analgesia and underwent technically difficult epidural catheter placement. The demographic characteristics, type of surgery, use of ultrasonography, method of insertion, intervertebral level, and success of epidural localization using colour Doppler were noted for each patient. Pain scores on postoperative day 1 and the presence of a patchy block were also reviewed.

RESULTS

Colour Doppler study helped to indicate the catheter's path from the skin to the epidural space during saline injection in 33 patients (89%). Saline flow within the epidural space (catheter tip confirmation) was successfully detected with colour Doppler in 25 patients (67.5%) and with M-mode ultrasonography in 28 patients (75%). Appropriate dermatomal analgesia was noted in 35 patients (94.5%) during local anesthetic infusion.

CONCLUSION

Our preliminary data suggest the feasibility of using colour Doppler and M-mode ultrasonography to confirm proper epidural catheter placement.

Visible Evidence of Lumbar Epidural Catheter Misplacement-A Critical Incident Case Report

One of the causes of failed epidurals is catheter misplacement. Though various techniques of epidural space identification have been developed, none of them is 100% successful. Here, we present a case of lumbar epidural catheter misplacement in a patient scheduled to undergo right sided open nephrectomy. Catheter was found in the surgical field coming out of psoas major muscle.

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.

Time-dependent changes in epidural catheter aspirate after injection of a local anesthetic

STUDY OBJECTIVE

A glucose check is used for investigation of a suspected accidental dural puncture in epidural anesthesia. However, glucose-positive clear fluid is sometimes aspirated from an epidural catheter in cases without clinical evidence of puncture. The goal of the study was to investigate time-dependent changes in the aspirate composition after injection of a local anesthetic into the epidural space.

DESIGN

Observational study.

SETTING

Operating rooms at Hamamatsu University Hospital.

PATIENTS

The subjects were 30 patients (ASA I or II) undergoing surgery with combined epidural and general anesthesia.

INTERVENTIONS

After epidural injection of local anesthetics, aspiration through the catheter was performed every 10min until fluid could not be aspirated. pH, Na, K, Cl, Ca and glucose were measured in fluid samples using a blood gas analysis apparatus.

MAIN RESULTS

No patients had pain or clinical signs suggesting dural puncture throughout the perioperative period. Fluid aspiration was possible in 15 patients (50%) after 10min and in 7, 3, 2 and 2 patients after 20, 30, 40 and 50min, respectively. Glucose was detected in each aspirated fluid sample and gradually increased with time to become closer to the level in cerebrospinal fluid (CSF). Each electrolyte also changed to approach the level found in CSF.

CONCLUSIONS

A glucose check may increase the risk of a false-positive finding for accidental dural puncture with increasing time after local anesthetic injection. Conversely, detection of glucose at the time of epidural catheter placement may provide useful information for detection of accidental dural puncture.

Lateral deviation of four types of epidural catheters from the lumbar epidural space into the intervertebral foramen

Background

During epidural anesthesia, the catheter tip occasionally deviates from the epidural space into the intervertebral foramen, resulting in inadequate anesthesia.

Methods

During postoperative plain radiography, iohexol was injected via the epidural catheter to determine its position and to observe the spread of the material. After exclusion of seven patients with catheters that migrated into the subcutaneous area and 25 patients with no evidence of the contrast medium, 415 patients were evaluated. We retrospectively compared patients to determine whether the incidence of deviation into the intervertebral foramen differed between four types of epidural catheters. We also investigated the load applied to the catheter tip using a Shimadzu Autograph AG-X-500 N-111 universal testing machine.

Results

Deviation of the epidural catheter into the intervertebral foramen was observed in eight and 33 patients in the Hakko and Perifix Soft tip catheter groups, respectively. The incidence of deviation was higher in the Perifix Soft tip catheter group, and lower in the FlexTip Plus and Perifix FX catheter groups. A rapid increase was observed in the force exerted on the tips of the Hakko and Perifix Soft tip catheters, while the force transmitted to the tips of the FlexTip Plus and Perifix FX catheters gradually increased and then reached a plateau at a low level.

Conclusions

The incidence of deviation was significantly lower with spiral-type catheters than with other types of catheters. This might be attributable to the gradual transmission of a lower level of force to the tip in spiral-type catheters.

Epidural catheter malposition in a failed epidural anesthesia confirmed by computed tomography

We report a case of failed epidural anesthesia despite successful identification of the epidural space, loss of resistance technique, hanging drop method and drip infusion. This case evaluated the use of computed tomography to confirm epidural catheter position, which showed the catheter accidentally positioned at the T2 lamina. Because epidural anesthesia can even after successful procedure using standardized techniques such as loss of resistance, we recommend performing the procedure under fluoroscopic guidance to improve success rate and patient safety.