1 Glasgow, UK 2 Nottingham, UK
EditorWe read with interest the case report of cerebrospinal fluid (CSF)-cutaneous fistula and pseudomonas meningitis complicating a thoracic epidural, by Abaza and Bogod.1 Two points of discussion have arisen.
First, were there signs of systemic inflammation (e.g. high or low white blood cell count, high or low core temperature, tachypnoea, or tachycardia) present before epidural catheter insertion? The presence of such signs could represent systemic sepsis, which is a relative contraindication to epidural anaesthesia. The majority of anaesthetists questioned in a survey of practice in England would not place an epidural in a patient with culture negative sepsis.2 We acknowledge that in this patient such signs might have been secondary to Crohns disease alone, but think that the potential risk outweighed any potential benefit from the epidural, particularly as the patient was receiving immunosuppressant drugs.
Second, an epidural catheter remaining in situ for 8 days is notably at odds with our own acute pain practice. In this department, most epidural catheters are removed on day 3, and all by day 5 (after correction of coagulopathy, if necessary). We appreciate that patient preference was a factor in the delayed removal in this case, but question whether the patient should have been offered a choice after 5 days had elapsed.
Most literature concerning timing of epidural catheter removal relates to anticoagulation or infection. Immunocompromise has been identified as a risk factor for the development of an epidural abscess,3 as has prolonged duration in situ.4 The incidence of a positive culture from epidural catheter tips steadily increases with duration with insertion,5 although duration is not identified as a risk factor for infection in some studies.6
In conclusion, we consider that the problem described was a complication of management of the epidural, rather than of epidural anaesthesia itself.
D. A. Blacoe
A. Ashworth
D. S. Ure
Glasgow, UK
EditorWe thank Drs Blacoe, Ashworth and Ure for their interest in our report, and for the opportunity to respond to the points they have raised.
With regard to our patients preoperative condition, he was admitted to hospital 1 week before his operation under the care of the physicians with an exacerbation of Crohns disease, having then been referred on to the surgical team 48 h before surgery. On the day of his operation, he had features of unresolving bowel obstruction (nausea, vomiting, abdominal pain, radiological evidence). He was clinically well rehydrated, apyrexial, heart rate 88/min, blood pressure 105/72 mm Hg, leukocyte count 9.1 cells mm3. There was therefore no reason to suspect underlying sepsis. We agree with Blacoe and colleagues that neuraxial block should not be performed in patients with untreated bacteraemia; however, catheter placement remains controversial in patients with systemic infection that is responding to antibiotic therapy.7
Early detection of epidural space infection (ESI) may sometimes be difficult as our report illustrates, with onset of symptoms and signs delayed for up to 60 days after catheter insertion being reported.5 Our patients condition was compounded by the occurrence of an unrecognized durocutaneous fistula, which exposed him to a higher risk of developing meningitis caused by breach of the dura.8
We acknowledge that steroid therapy placed our patient in a higher risk category for ESI, but other risk factors identified also include diabetes, chronic renal failure, anorexia, chronic alcohol abuse, and cancer.9 Denying such a sizeable group of patients the potential benefits of epidural analgesia cannot be recommended, but a riskbenefit assessment should be undertaken in discussion with the patient. Provided the patient is fully informed of the risks involved, we believe they indeed should be given the choice of keeping epidurals in situ for longer than average if they so wish.
Evidence from the literature, however, is inconclusive as to the timing of epidural catheter removal to prevent ESI after use for postoperative analgesia. A review by Ngan Kee and colleagues10 showed that the majority of cases of catheter-associated epidural abscess involved cases where catheters were in place for 5 days or less, and concluded that a long duration of catheterization was not a risk factor. Another review confirmed that in 52% of cases catheters were in situ for 5 days or less, whereas only 24% were in place for >5 days.9 This led Breivik11 to conclude that duration of epidural catheterization was not a decisive factor for developing an ESI.
This lack of conclusive evidence is reflected in our hospitals Acute Pain Service guidelines for management of epidurals, where there is no specified time after which catheters must be removed. This may also reflect our surgical caseload, which includes thoracic and upper gastrointestinal surgery, where surgeons are actively supporting use of epidurals for longer periods postoperatively for their perceived benefits. Review of such guidelines after this unfortunate case has resulted in tightening of the procedures for insertion and follow-up of epidurals, as well as post-insertion infection control precautions to minimize infection risk. Nursing and trainee medical staff education should highlight the need for vigilance for early recognition of this rare but serious complication.
K. T. Abaza
D. G. Bogod
Nottingham, UK
References
1 Abaza KT, Bogod DG. Cerebrospinal fluid-cutaneous fistule and pseudomonas meningitis complicating thoracic epidural analgesia. Br J Anaesth 2004; 92; 42931
2 Low JH. Survey of epidural analgesia management in general intensive care units in England. Acta Anaesthesiol Scand 2002; 46: 799805[CrossRef][ISI][Medline]
3 Wang LP, Schmidt JF. Severe infections after epidural catheterisation. Ugeskr Laeger 1998; 160: 32026[Medline]
4 Wang LP, Haurberg J, Schmidt JF. Long-term outcome after neurosurgically treated spinal epidural abscess following epidural analgesia. Acta Anaesthesiol Scand 2001; 45: 2339[CrossRef][ISI][Medline]
5 Simpson RS, Macintyre PE, Shaw D, Norton A, McCann JR, Tham EJ. Epidural catheter tip cultures: results of a 4-year audit and implications for clinical practice. Reg Anesth Pain Med 2000; 25: 3607
6 Darchy B, Forceville X, Bavoux E, Soriot F, Domart Y. Clinical and bacteriologic survey of epidural analgesia in patients in the intensive care unit. Anesthesiology 1996; 85: 98898[CrossRef][ISI][Medline]
7 Horlocker TT. Complications of spinal and epidural anesthesia. Anesthesiol Clin North America 2000; 18: 46185[Medline]
8 Bouhemad B, Dounas M, Mercier FJ, Benhamou D. Bacterial meningitis following combined spinal-epidural analgesia for labour. Anaesthesia 1998; 53: 2925[CrossRef][ISI][Medline]
9 Kindler CH, Seeberger MD, Staender SE. Epidural abscess complicating epidural anesthesia and analgesia. An analysis of the literature. Acta Anaesthesiol Scand 1998; 42: 61420[ISI][Medline]
10 Kee WD, Jones MR, Thomas P, Worth RJ. Extradural abscess complicating extradural anaesthesia for Caesarean section. Br J Anaesth 1992; 69: 64752[Abstract]
11 Breivik H. Neurological complications in association with spinal and epidural analgesiaagain. Acta Anaesthesiol Scand 1998; 42: 60913[ISI][Medline]