Intrathecal Migration of an Epidural Catheter While

Intrathecal Migration of an Epidural Catheter While Using a Programmed Intermittent Epidural Bolus Technique for Labor Analgesia Maintenance: A Case Report Francesca Betti, MD, Brendan Carvalho, MBBCh, FRCA, and Edward T. Riley, MD We describe a case of intrathecal migration of a wire-reinforced epidural catheter in a parturient who received epidural labor analgesia. Epidural analgesia was initiated with a combined-spinal epidural technique and maintained by programmed intermittent epidural boluses. Epidural catheter aspiration after insertion was negative for cerebrospinal fluid. The patient’s response to the first four doses of local anesthetic was consistent with epidural drug delivery. After the fifth dose, she developed a complete lower extremity motor block, hypotension, and high sensory blockade. Catheter aspiration was then positive for cerebrospinal fluid. After symptom resolution, labor pain was successfully managed with this inadvertent intrathecal catheter. (A&A Case Reports. 2017;XXX:00–00.)

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he incidence of inadvertent dural puncture during labor epidural placement ranges from 0.6% to 2.7%.1 The majority of accidental dural punctures are typically recognized at placement, either from cerebrospinal fluid (CSF) return from the epidural needle or aspiration from the catheter, a positive test dose response, or an exaggerated response to local anesthetic administration through the epidural catheter.1–3 However, intrathecal catheters have been reported despite negative catheter aspiration for CSF.1 While intravascular migration of an epidural catheter is a known complication of epidural analgesia with an indwelling catheter,3 migration of a catheter from the epidural to intrathecal space is exceedingly rare, with only a few case reports in the literature.4,5 Furthermore, to our knowledge, there has never been a documented case of intrathecal migration of a labor epidural catheter with the new generation of softer wire-reinforced epidural catheters. These catheters are considered to be lower risk for intravascular and subarachnoid puncture compared to the older stiffer nylon or polyurethane catheters.6,7 We present a case of a laboring woman who experienced a suspected intrathecal migration of a wire-reinforced epidural catheter 3 hours after initiation of combined spinal-epidural (CSE) placement for labor analgesia. The case emphasizes the potential pitfalls of a programmed intermittent epidural bolus (PIEB) system with an untested epidural catheter for labor analgesia and the importance of constantly evaluating patients for signs and symptoms of intrathecal catheter placement or migration. Written informed consent was provided by the patient for publication of this report. From the Department of Anesthesiology, Perioperative, and Pain Medicine, Stanford University School of Medicine, Stanford, California. Accepted for publication June 16, 2017 Funding: None. Conflicts of Interest: See Disclosures at the end of the article. Address correspondence to Edward T. Riley, MD, Department of Anesthesiology, Perioperative and Pain Medicine, Stanford University Medical Center, 300 Pasteur Dr, Stanford, CA 94305. Address e-mail to [email protected]. Copyright © 2017 International Anesthesia Research Society DOI: 10.1213/XAA.0000000000000616

CASE DESCRIPTION A 27-year-old gravida 3 para 1 woman at 37 weeks and 2 days gestation was admitted to the labor and delivery ward for induction of labor secondary to gestational hypertension. She was otherwise healthy and had a history of one prior normal spontaneous vaginal delivery with epidural analgesia without complication. During admission, the patient requested epidural analgesia for labor analgesia. A CSE technique was performed. After an initial unsuccessful attempt at the L4-L5 interspace, the L3-L4 epidural space was found using a loss of resistance technique with normal saline with a 17-gauge Tuohy needle (B. Braun Medical Inc, Bethlehem, PA). Crisp loss of resistance was encountered at a depth of 9 cm, with no CSF return from the hub of the Tuohy needle. A 26-gauge, 124-mm pencilpoint spinal needle (Gertie Marx, IMD, Huntsville, UT) was inserted through the Tuohy needle, and a 1.1-mL dose containing isobaric bupivacaine 2.5 mg and sufentanil 5 µg was administered intrathecally. There was no CSF return from the Tuohy needle. A 19-gauge open-tip, wire-reinforced epidural catheter (Perifix Springwound; B. Braun Medical Inc) was inserted and then aspirated with no return of blood or CSF. The epidural pump (CADD-Solis Infusion Pump; Smiths Medical, St. Paul, MN) was started after the epidural catheter placement. As per our institution’s practice, a “standard” epidural test dose (3 mL of 1.5% lidocaine with 15 µg epinephrine) was not administered. The epidural pump was programmed to administer a PIEB of 9 mL of 0.0625% bupivacaine with sufentanil 0.4 µg/mL solution every 45 minutes with patient-controlled epidural analgesia boluses of 10 mL every 10 minutes as needed, starting 30 minutes after epidural placement. After receiving the intrathecal dose of bupivacaine and sufentanil, the patient reported resolution of her labor pain. She was hemodynamically stable and easily moving both lower extremities. The nurses monitored blood pressure and heart rate every 15 minutes. Pain scores were checked hourly, and fetal heart rate was monitored continuously.

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The first PIEB dose was given 30 minutes after the initial spinal dose. The patient’s blood pressure decreased from 110/69 to 88/39 mm Hg. She received 500 mL lactated Ringer’s solution and was positioned supine with left uterine displacement. Blood pressure increased to 101/67 mm Hg within 10 minutes. The patient did not experience any motor block, dyspnea, nausea, or other symptoms during this time. The patient continued to receive PIEB doses for 3 hours without any symptoms or complications. She had one episode of hypotension to 85/41 mm Hg, not temporally linked to any epidural bolus, which immediately resolved with repositioning to relieve aortocaval compression. When the patient received the fifth PIEB dose, she became hypotensive with a blood pressure of 81/42 mm Hg with newonset nausea and dyspnea. She was immediately assessed and found to have sudden-onset complete motor block of her lower extremities and sensory level to cold at T3-T4. The sensory level had been T9-T10 previously with no motor block. On testing, CSF was easily aspirated through the catheter, and the epidural pump was stopped. The hypotension was treated with ephedrine 10 mg, phenylephrine 100 µg, and 500 mL lactated Ringer’s solution, and she received ondansetron 4 mg to treat nausea. Hypotension, dyspnea, and nausea resolved within 15 minutes, and the motor block resolved within 2 hours. Labor pain returned and the suspected intrathecal catheter was successfully used to provide labor analgesia with a continuous infusion rate of 1 to 2 mL/h using the same epidural local anesthetic solution. The patient had a sensory block to T6 for the rest of the labor. She could move her legs; formal testing of motor block was not performed. The patient delivered a healthy baby vaginally approximately 12 hours later. The suspected inadvertent intrathecal catheter was removed soon after delivery. The patient had no postdural puncture headache or other complications in the postpartum period.

DISCUSSION We report a suspected migration of a wire-reinforced epidural catheter into the intrathecal space during labor analgesia. Epidural catheter migration is a recognized complication of epidural analgesia, with a rate of intravascular migration of 0.25% in one study of stiff epidural catheters.3 The incidence of intrathecal migration of epidural catheters remains unknown and is limited to a few case reports.4,5 To our knowledge, intrathecal catheter migration has never been reported with newer wire-reinforced epidural catheters. These catheters have an even lower incidence of intravascular puncture during catheter insertion compared to stiffer polyamide or nylon catheters.6–8 It is postulated that this flexible catheter structure reduces the risk of intrathecal migration.6 Presumably, this case is the first report of intrathecal migration with the Perifix Springwound wire-reinforced epidural catheter. It demonstrates that even this softer, more flexible catheter does not eliminate the risk of catheter migration. The Serious Complication Repository Project of the Society for Obstetric Anesthesia and Perinatology reported an unrecognized intrathecal catheter rate of 1 in 15,435.9 It is unknown if any of these catheters migrated intrathecally after initial epidural dosing, but the data demonstrate the need for constant vigilance to avoid the potential complications of unrecognized intrathecal catheters.

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Anatomical studies suggest that puncture of intact dura by an epidural catheter is highly unlikely, but puncture of an epidural catheter through the arachnoid mater can occur.10 This epidural catheter may have initially been inserted into the subdural space, functioned as if in the epidural space for the first four PIEB doses, and migrated through the arachnoid mater into the intrathecal space. Another possibility is that the dura was partially cut by the Tuohy needle during CSE placement and that the epidural catheter later migrated intrathecally through a partial dural tear. The PIEB technique is a relatively new epidural labor analgesia maintenance option.11 Reported benefits of PIEB include reduced number of physician rescue supplementary boluses, decreased overall local anesthetic dose, increased maternal satisfaction with analgesia, decreased motor blockade, shorter duration of labor, and decreased instrumental deliveries.11–13 However, early adopters of PIEB speculated that there may be a risk of delayed recognition of an intrathecal catheter associated with the technique compared to continuous epidural infusions started immediately after epidural or CSE placement.14 With the CSE technique, patients get initial analgesia from the spinal dose and many practitioners do not test the catheter before starting the epidural pump. Epidural test doses have limited usefulness in the setting of epidural labor analgesia,14,15 and many practices, including ours, have therefore abandoned its use. In the setting of a CSE without an epidural test dose, the first dose through the epidural catheter will be the first PIEB dose, which is by design 30 to 60 minutes after the block is placed. Therefore, PIEB dosing should be low enough that if intrathecal dosing does occur, no harm will come to the patient. We believe our protocol of 9 mL of 0.0625% bupivacaine (5.6 mg) is appropriate, and we encourage others to keep their PIEB and patient-controlled epidural analgesia demand doses below 8 mg bupivacaine. A test dose may be prudent after a CSE, especially if a small PIEB dose and adequate ongoing monitoring cannot be assured. However, an initial test dose will not pick up subsequent intrathecal migration of an epidural catheter, which likely occurred in this case. In summary, we describe the first reported case consistent with intrathecal migration of a wire-reinforced epidural catheter. The apparent intrathecal migration occurred after the fifth PIEB bolus approximately 3 hours after the initial CSE for epidural labor analgesia. This case demonstrates the necessity of constant vigilance when delivering continuous epidural analgesia to the parturient and the value of educating both nursing staff and patients on signs and symptoms of an intrathecal catheter so that prompt intervention by an anesthesia provider can occur. Blood pressure and motor blockade should be monitored regularly and proper resuscitation equipment should be immediately available. The importance of limiting the PIEB bolus dose is also shown by this case, and that harm can be mitigated if the PIEB dose of local anesthetic is small enough to not result in a high or total spinal if accidentally administered intrathecally. E DISCLOSURES Name: Francesca Betti, MD. Contribution: This author helped care for the patient and write the manuscript. Conflicts of Interest: None.

A & A CASE REPORTS


Name: Brendan Carvalho, MBBCh, FRCA. Contribution: This author helped write the manuscript. Conflicts of Interest: Brendan Carvalho has received funding for research from Covidien LP and is a consultant for Smiths Medical and Pacira Pharmaceuticals. Name: Edward T. Riley, MD. Contribution: This author helped write the manuscript. Conflicts of Interest: None. This manuscript was handled by: Hans-Joachim Priebe, MD, FRCA, FCAI. REFERENCES 1. Richardson MG, Lee AC, Wissler RN. High spinal anesthesia after epidural test dose administration in five obstetric patients. Reg Anesth. 1996;21:119–123. 2. Okell RW, Sprigge JS. Unintentional dural puncture. A survey of recognition and management. Anaesthesia. 1987;42:1110–1113. 3. Pan PH, Bogard TD, Owen MD. Incidence and characteristics of failures in obstetric neuraxial analgesia and anesthesia: a retrospective analysis of 19,259 deliveries. Int J Obstet Anesth. 2004;13:227–233. 4. Crawford JS. Some maternal complications of epidural analgesia for labour. Anaesthesia. 1985;40:1219–1225. 5. Frohlick S. A rare case of epidural catheter migration? Minerva Anestesiol. 2012;78:858–859. 6. Banwell BR, Morley-Forster P, Krause R. Decreased incidence of complications in parturients with the arrow (FlexTip Plus) epidural catheter. Can J Anaesth. 1998;45:370–372. 7. Shih CK, Wang FY, Shieh CF, et al. Soft catheters reduce the risk of intravascular cannulation during epidural

block—a retrospective analysis of 1,117 cases in a medical center. Kaohsiung J Med Sci. 2012;28:373–376. 8. Mhyre JM, Greenfield ML, Tsen LC, Polley LS. A systematic review of randomized controlled trials that evaluate strategies to avoid epidural vein cannulation during obstetric epidural catheter placement. Anesth Analg. 2009;108:1232–1242. 9. D’Angelo R, Smiley RM, Riley ET, Segal S. Serious complications related to obstetric anesthesia: the serious complication repository project of the Society for Obstetric Anesthesia and Perinatology. Anesthesiology. 2014;120:1505–1512. 10. Hardy PA. Can epidural catheters penetrate dura mater? An anatomical study. Anaesthesia. 1986;41:1146–1147. 11. McKenzie CP, Cobb B, Riley ET, Carvalho B. Programmed intermittent epidural boluses for maintenance of labor analgesia: an impact study. Int J Obstet Anesth. 2016;26:32–38. 12. Capogna G, Camorcia M, Stirparo S, Farcomeni A. Programmed intermittent epidural bolus versus continuous epidural infusion for labor analgesia: the effects on maternal motor function and labor outcome. A randomized double-blind study in nulliparous women. Anesth Analg. 2011;113:826–831. 13. Carvalho B, George RB, Cobb B, McKenzie C, Riley ET. Implementation of programmed intermittent epidural bolus for the maintenance of labor analgesia. Anesth Analg. 2016;123:965–971. 14. Mulroy MF, Norris MC, Liu SS. Safety steps for epidural injection of local anesthetics: review of the literature and recommendations. Anesth Analg. 1997;85:1346–1356. 15. Cohen SE, Yeh JY, Riley ET, Vogel TM. Walking with labor epidural analgesia: the impact of bupivacaine concentration and a lidocaine-epinephrine test dose. Anesthesiology. 2000;92:387–392.

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