Epidural haematoma
Editor—We read with interest the recent case report in which a patient treated with clopidogrel and dalteparin developed an epidural haematoma following a combined spinal-epidural anaesthetic.1 Although the authors describe the commonly quoted incidence of spinal haematoma following epidural and spinal anaesthesia between 1 in 150 000 and 1 in 220 000, the true incidence is unknown. The Victorian Consultative Council on Anaesthetic Mortality and Morbidity (VCCAMM) is a system that monitors, analyses and reports on key areas of potentially preventable anaesthetic mortality and morbidity within the Victorian hospital system in Australia.2 It has recently reported a number of major complications following regional anaesthesia techniques with concerns regarding the delay in diagnosis and treatment of neurological compromise.3 Unfortunately Tam and colleagues1 in their discussion omit practical advice on how spinal haematomas can be diagnosed, given the necessity for an urgent response to begin corrective treatment within a narrow 6–12 h ‘window of opportunity’. VCCAMM has responded with useful advice to detect such complications.3 Common presenting signs and symptoms of neurological compression include onset of new severe or persistent back pain, loss or change of motor function (which may be erroneously attributed to the local anaesthetic), major change in sensory level or density, any deterioration in observed parameters from a pre-existing steady state, and most importantly there must be recognition of the need to communicate urgently with an anaesthetist or acute pain team. It is disappointing that the patient had complained of back pain in the evening of the day of surgery with abnormal neurology detected the day after surgery and yet there was a 48 h delay after removing the epidural catheter before obtaining a magnetic resonance imaging (MRI) scan to detect what is a neurosurgical emergency. However, the authors are to be congratulated on publishing and highlighting a complication that we believe is under-reported. If a spinal haematoma is suspected, an urgent MRI or computed tomography myelogram and neurological or neurosurgical referral within hours is essential. Clearly, the diagnosis of spinal haematomas is difficult. However, given the ever increasing use of clopidogrel, low molecular weight heparins and other newer anticoagulants, we agree with Tam and colleagues that it is vital that we increase our vigilance and close neurological monitoring of these patients who undergo spinal and/or epidural anaesthesia.R. G. Davies*
N. A. Harris
Cardiff, UK
*E-mail: rgd{at}btinternet.com
Editor—We read with interest the case report by Tam and colleagues1 describing epidural haematoma following combined spinal-epidural (CSE) anaesthesia for total knee arthroplasty in a patient receiving clopidogrel. This case highlights the importance of vigilance in these patients. Despite adhering to American Society of Regional Anesthesia and Pain Medicine (ASRA) guidelines and recommendations the patient unfortunately developed a rare but potentially devastating complication of central neuraxial blockade. We wonder whether current recommendation from ASRA, of stopping clopidogrel 7 days before neuraxial blockade, needs to be reviewed.4
The risk of CSE in patients treated with newer antiplatelet agents is unclear. The routine laboratory tests for assessing coagulation are not effective for monitoring platelet function inhibition with these agents. Modified thromboelastography could prove useful for monitoring reversal of clopidogrel inhibition.5 Altered coagulation is recognized as an important risk factor in the development of spinal haematoma. Peripheral nerve blockade (PNB) may be a less risky alternative to central neuraxial blockade in unilateral lower limb arthroplasty.6 The increasing use of clopidogrel may alter the balance of argument in favour of PNB and against CSE in the setting of orthopaedic procedure.
S. R. Sawant*
M. Bhagwat
Kings Lynn, UK
*E-mail: drshilpasawant{at}rediffmail.com
Editor—We would like to thank Drs Davies and Harris for their interest and comments regarding the case report. By publishing this case report we hope to maintain and increase awareness of a complication that although rare can have devastating consequences for the patient.
It is often easier in retrospect to see the sequence of events and the combination of physical signs suggesting an epidural haematoma. With reference to our case the patient did complain of back pain although she was known to suffer from a degenerative spine. However, we agree that in combination with the abnormal neurology that subsequently developed, such ‘red flag’ signs should cause one to immediately consider an epidural haematoma. Although the physiotherapist noted some abnormal neurology, this information was not conveyed to the duty anaesthetic team. Guidelines in our hospital have since been reviewed to ensure adequate monitoring of patients receiving central neuraxial anaesthesia. Any suspicion of an epidural haematoma should in the first instance involve stopping or reducing the infusion to assess if the signs regress. Further regular assessment is necessary because of the narrow window of opportunity for intervention as mentioned by Davies. The unfortunate delay between the time from when the haematoma was suspected to obtaining an MRI was mainly because of the need to transfer the patient to another hospital.
We would like to thank Drs Sawant and Bhagwat for their interest in our case report. Clopidogrel has an irreversible effect on platelet function and at the time of the incident the manufacturer's recommendations was to stop the agent 7 days before surgery. However, since this case we have changed practice in our department to stopping clopidogrel 10 days before elective surgery.
Bleeding time is not an ideal measurement of platelet function in patients on antiplatelet agents and as mentioned modified thromboelastography5 (TEG®) may become a necessary test to assess such patients. A preoperative bedside test would resolve issues regarding platelet function in such patients, especially as the use of combinations of antiplatelet agents is becoming more prevalent.
Although guidelines are present for the performance of neuraxial blocks on patients receiving anticoagulants there are few recommendations for peripheral blocks. There have been case reports of severe bleeding complications including fatal outcomes in patients that have undergone lower extremity peripheral nerve blocks and ASRA guidelines4 have suggested that recommendations for performing these blocks should be similar to those for neuraxial blocks.
Performing a central neuraxial block on patients receiving antithrombotic medication is usually a risk benefit analysis and commonly the population receiving such agents are often the ones that benefit most from a neuraxial or regional technique.
The incidence of epidural haematomas is rare and is based on retrospective analysis and case reports but the neurological outcome can be devastating for the patients. By reporting such cases we hope to increase awareness of this complication and vigilance in all patients receiving central neuraxial anaesthesia.
N. L. Tam*
C. Pac-Soo
P. M. Pretorius
High Wycombe, UK
*E-mail: nicolettetam{at}hotmail.com
References
1 Tam NL, Pac-Soo C, Pretorius PM. Epidural haematoma after a combined spinal-epidural anaesthetic in a patient treated with clopidogrel and dalteparin. Br J Anaesth 2006; 96:262–5
2 Victorian Consultative Council on Anaesthetic Mortality and Morbidity. Available from http://www.health.vic.gov.au/vccamm/index.htm
3 Victorian Consultative Council on Anaesthetic Mortality and Morbidity. Neurological complications of regional anaesthesia—early consultation with the anaesthetist. 2005; Available from http://www.health.vic.gov.au/vccamm/articles/neuro.pdf
4 Horlocker TT, Benzon H, Brown DL, et al. Regional anaesthesia in the anticoagulated patient: defining the risks (the Second ASRA Consensus Conference on Neuraxial Anesthesia and Anticoagulation). Reg Anesth Pain Med 2003; 28:172–97[CrossRef][Web of Science][Medline]
5 Craft RM, Chavez JJ, Bresee SJ, et al. A novel modification of the thromboelastograph assay, isolating platelet function, correlates with optical platelet aggregation. J Lab Clin Med 2004; 143:301–9[CrossRef][Web of Science][Medline]
6 Mentegazzi F, Danelli G, Ghisi D, et al. Locoregional anesthesia and coagulation. Minerva Anesthesiol 2005; 71:497–9
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