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Correspondence |
* Tsukuba University, Ushiku Aiwa General Hospital,
Tsukuba-Gakuen Hospital,
Tsukuba, Ibaraki, Japan, E-mail: taekof{at}md.tsukuba.ac.jp
To the Editor:
We present a case wherein an entrapped epidural catheter required general anesthesia with muscle relaxation for removal.
A 40-yr-old, 160-cm, and 50-kg woman was scheduled for transabdominal hysterectomy and oophorectomy. With the patient in the right lateral position, a 19-G Arrow Flextip PlusTM (Arrow International, Reading, PA, USA) epidural catheter was inserted at the T11-12 interspace via a median approach. The catheter was secured to the skin at the 10-cm mark. The epidural catheter was used successfully for anesthesia during surgery and for analgesia after surgery. On the second day, resistance was encountered upon trying to remove the catheter. An abdominal roentgenogram showed neither knotted nor looped catheter. The catheter could be withdrawn to the 7-cm mark at the skin by repeated removal attempts in varied positions. However, a stretched and fragile part was found in the catheter. We explained the risk of further attempts with limited flexed positioning, and obtained informed consent for general anesthesia. Thiamylal and vecronium were administered to facilitate oral intubation, and general anesthesia was maintained with sevoflurane and nitrous oxide. The patient was placed in the right lateral position with her back maximally flexed, and the catheter could then be removed without breaking.
A fundamental rule for removing an entrapped epidural catheter is to place the patient in the same position as they were at the time of its insertion. However, the lateral position is better than sitting, because more than twice as much force is required to remove the catheter when the patient is sitting.1 Radiography is important for the early diagnosis. An electronic scale might be also useful. The force required to remove an epidural catheter does not exceed 0.6 kg in usual cases.2 The fracture force of Arrow and Portex catheters are about 2 and 2.6 kg, respectively.2,3 Other strategies to facilitate removal include: 1) discontinue efforts temporarily to allow tissue relaxation; 2) tie a weight to the catheter and let it hang down; 3) withdraw the catheter under sedation; 4) thread a sterile Tuohy needle over the catheter into the epidural space and withdraw them en bloc and; 5) inject saline through the catheter to widen and lubricate the surrounding space.4 Never risk damaging the entrapped catheter. Special attention was given to the Arrow catheter in our patient because it has a weak segment between the 7- and 8-cm marks.5
In conclusion, we found that general anesthesia was an effective option to remove an entrapped epidural catheter, because it completely alleviated the pain of the surgical wound, relaxed the muscles, and enabled the patient to flex maximally.
References
1 Boey SK, Carrie LE. Withdrawal forces during removal of lumbar extradural catheters. Br J Anaesth 1994; 73: 833–5.
2 Davies R, Vaughan RS, Richards J. Epidural catheters. Breaking and extraction forces. Anaesthesia 1993; 48: 900–1.[Medline]
3 Tsui BC, Finucane B. Tensile strength of 19- and 20-gauge arrow epidural catheters. Anesth Analg 2003; 97: 1524–6.
4 Jongleux EF, Miller R, Freeman A. An entrapped epidural catheter in a postpartum patient. Reg Anesth Pain Med 1998; 23: 615–7.[Medline]
5 Asai T, Yamamoto K, Hirose T, Taguchi H, Shingu K. Breakage of epidural catheters: a comparison of an arrow reinforced catheter and other nonreinforced catheters. Anesth Analg 2001; 92: 246–8.
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