Difficult extubation caused by knotting of an epidural catheter：a case report

doi:10.21203/rs.3.rs-3641885/v1

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Case Report

Difficult extubation caused by knotting of an epidural catheter：a case report

https://doi.org/10.21203/rs.3.rs-3641885/v1

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Background

Combined spinal-epidural (CSE) anaesthesia is the preferred anesthesia method for cesarean delivery. However, it is very rare in knotting of epidural catheters that most require surgery to remove the catheter.

Case presentation:

A 30-year-old parturient with a difficulty in epidural catheter extraction after cesarean section. CT scan revealed that the catheter had formed a tight knot in the epidural space. We reviewed relevant case reports and summarized the latest research progress, We removed the catheter by non-invasive means of opening the joint to the maximum extent possible.

Conclusion

This case suggests that in cases of difficulty in catheter removal, immediate use of imaging techniques such as CT scan should be recommended to assess the catheter's positioning and trajectory. Demonstrate our method is a simple, cost-effective treatment that clinicians can implementeasily and quickly into routine practice.

Combined spinal-epidural anaesthesia

Epidural catheter

knotting

Difficult extubation

Difficult removal of the epidural catheter is one of the complications of continuous epidural anesthesia. The reasons for this difficulty usually include the compression of the catheter in the narrow intervertebral space or the formation of loops, tangles, or knots within the epidural space. Catheter knotting leading to difficult removal is a very rare phenomenon ^[1].Here,we report a case of case of a difficulty in epidural catheter extraction after cesarean section.

A 30-year-old parturient (weight, 80kg; height, 154 cm, BMI 33.7), with single pregnancy at 38 weeks, was scheduled to undergo planned cesarean delivery. The pregnant patient was positioned in a right lateral tilt position. The midline puncture through the L2-3 intervertebral space was performed, but encountered resistance after several needle direction adjustments. An alternate paramedian puncture method was used, and the resistance was reduced. When the needle reached approximately 7 cm, a sensation of ligamentum flavum breakthrough was felt. A negative pressure test confirmed that the epidural puncture needle had entered into the epidural space. A spinal needle was then inserted through the epidural needle, with a breakthrough sensation of dura mater puncture but no evidence of nerve stimulation. The flowing of Clear cerebrospinal fluid was observed. And 1.8 ml of 0.5% ropivacaine was slowly injected. The spinal needle was removed, leaving a reinforced catheter 5 cm in length within the epidural space. The exposed end of the catheter was secured to the patient's back using adhesive tape. Anesthesia during the surgery was effective. And the surgery was performed smoothly.

Ten min before the end of the operation, the initial dose of analgesia was injected in failure via the epidural catheter because of high push resistance. It was preliminarily speculated that a certain portion of the catheter might have formed a knot under pressure of the patient's back. However, no knots was found in the catheter on the patient's back after the surgery. The patient was repositioned in a right lateral tilt position. But an attempt of removal of the catheter was unsuccessful. The patient did not suffer any pain or abnormal sensations during the catheter traction process. The decision was made to defer the catheter removal. And disinfect, dress, and secure the exposed portion of the catheter was perfermed. Intravenous analgesia was performed instead. With the patient and family's consent, an emergency computed tomography (CT) examination was performed, which showed a tight knot in the catheter at the right subvertebral notch of the L2 vertebra (Fig. 1A-C).Through practice on the spinal model, it was found that when the patient was placed in a left lateral position with the extension of the left lower limb and the flexion of the right lower limb at a 90-degree angle, the anesthesiologist exerted pressure on the patient's right scapula, pushing it back and down with the left hand, while simultaneously pushing the patient's right hip joint forward with the right hand, which could open the right-sided facet joint of the lumbar vertebrae to the greatest extent (Fig. 2A, B). With the patient and family's consent, a cautious attempt was made at bedside to remove the catheter by using this method. The catheter was gently pulled with a constant force. Although the resistance was existed, the catheter was successfully removed. And there was no pain or abnormal sensations during the removal process. It was observed that a knot had formed in the catheter approximately 3.2 cm from the catheter tip. Additionally, under continual tension, the inner wire coil of the catheter had been significantly elongated, while the outer part of the catheter coil at a distance of 8 cm from the tip had fractured with an intact end (Fig. 3). The patient was followed up for one week after the catheter removal. And there were no adverse complaints or complications.

The length of the catheter remained in the epidural space is a highly debated issue regarding the cause of catheter knotting. Some authors believed that a catheter length of 5 cm retained in the epidural space is optimal, considering both analgesia and reducing the risks of catheter looping, extrusion, or inadvertent inadvertent arterial placement ^{[2, 3]}. Other authors suggested that retaining the catheter length within 3–4 cm from the catheter tip could prevent a 180° rotation and subsequent knot formation ^[1]. However, there have been reports of knot formation with the catheter length retained within 3 cm from the catheter tip ^[4]. In our study, the knot was located approximately 3.2 cm from the catheter tip. J. F. Brichant reported a tight single knot at a distance of 4 mm from the catheter tip ^[5]. Toshiyuki Mizota reported a firm single knot at a distance of approximately 3 mm from the catheter tip ^[6]. From the above, there is no gold standard for the length of catheter retention within the epidural space to prevent knot formation. Among the reported cases, knot formation in the lumbar region was more common than in the thoracic region ^[6]. This might be attributed to the perpendicular angle of needle insertion in the lumbar region and the obtuse angle in the thoracic region ^[7], with the latter being more favorable for catheter insertion and advancement within the epidural space.

Are there any other methods that can help reduce the occurrence of catheter knotting? Improving the success rate of puncture and placement of catheters is particularly important. Obesity in patients often leads to a higher failure rate of epidural puncture and catheter placement ^[8]. It could help improve the success rate of puncture and catheter placement ^[9] and accurately identify the position of the puncture needle tip ^[10] by using ultrasound-guided intrathecal puncture and needle guidance techniques. In a study by Oscar et al., it was found that the blood flow in the epidural space and the path of the catheter in the epidural space could be indirectly visualized by injecting 1 mL of normal saline into the catheter and using color Doppler ultrasound ^[11], which helped to determine whether the catheter is forming loops or knots in the epidural space.

When faced with difficulty in removing the epidural catheter, it was recommended for considering a flexed lateral position during removal ^[12–15]. Although in most cases of catheter knotting, a constant gentle pull could successfully remove catheters, with catheter breakage in approximately 30% of those cases that finally had been treated for surgical removal ^{[13, 16–18]}. It was reported that the catheter had been successfully removed under general anesthesia with muscle relaxation ^{[19, 20]}, which should only be considered in the case of the patient in the awake state without neurological pains or sensory abnormalities during previous catheter removal. If any abnormal neurologic symptoms occur during catheter removal, it must be stopped because there is a possibility of the catheter entwining with nerve roots, blood vessels, or other structures ^[21]. In our case, it is speculated that the epidural needle did not enter the epidural space in the correct order of supraspinous ligament, interspinous ligament, and ligamentum flavum by the paramedian puncture. Instead, the epidural needle traversed through the adjacent paraspinal tissue and entered the epidural space through the vertebral lamina fissure near the right upper and lower facets of the L2-3 vertebrae, ultimately leading to knot formation in the epidural space.

There were research testing results referring that reinforced catheters could withstand greater pulling force compared to traditional polyethylene or polyurethane catheters ^[22]. Takashi Asai reported a case occurring a reinforced catheter broken at a distance of 7–8 cm from the catheter tip during removal, with the broken distal end remaining in the patient's body, while the steel wire from the distal end was still attached to the removed segment of the catheter ^[18]. Therefore, continuous strong pulling should be avoided even for reinforced catheters. In our case, it was also observed that the fracture of the catheter sheath had occurred at a distance of 8 cm from the distal end, which was possibly because of the low-density distal end of wire coils in the 7–8 cm segment ^[18]. The complete removal of the entire catheter in our case could have been attributed to the catheter knotting, which prevented the fractured distal end of the catheter detaching from the inner wire coils. Additionally, it is worth considering that although reinforced catheters have improved tensile strength, they are generally more flexible than traditional polyethylene or polyurethane catheters. This raises the question of whether reinforced catheters may be more prone to tangling and knotting when encountering resistance during placement into the epidural space.

CSE Combined spinal-epidural

Acknowledgements

We thank the puerpera for her collaboration，and all the Medical workers who have contributed to this.

Authors’ contributions

Nianhua Deng and Xiaocong Chen drafted the article(Supervision; Writing – original draft);.Shoubo Quan revised the manuscript (Conceptualization; Supervision; Writing – review & editing).

Funding

Not applicable.

Data Availability

The datasets used and/or analysed during the current study available from the corresponding author on reasonable request.

Ethics approval and consent to participate

Not applicable.

Consent for publication

Written informed consent was obtained from the patient for publication of this case report and any accompanying images.

Competing interests

The authors declare that they have no competing interests.

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No competing interests reported.

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Difficult extubation caused by knotting of an epidural catheter：a case report

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Abstract

Background

Case presentation:

Conclusion

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Background

Case presentation

Discussion and conclusions

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