◊ BACKGROUND:
Meningeal (postdural) puncture headache (MPH) is a familiar iatrogenic complication. The optimal means of prevention, management, and treatment of this disorder are uncertain. The purpose of this study was to determine current practice among United States (USA) anesthesiologists regarding MPH as well as the related issues of unintentional dural puncture (UDP), the epidural blood patch (EBP), and proposed alternatives to the EBP.
◊ METHODS:
A survey form was sent as a single mailing to each practicing USA member of the American Society of Regional Anesthesia and Pain Medicine in June 2006.
◊ RESULTS:
Data were analyzed from 1024 returned survey forms (29.4% response rate). Major findings were as follows: Written institutional protocols for managing UDP and MPH are uncommon. The preferred method of immediately dealing with an UDP when providing analgesia for labor is to reattempt the epidural at another level (73.4%). When intrathecal catheters are used for labor analgesia, they are most often removed immediately after delivery (56.5%). After UDP in the obstetric setting, aggressive hydration and encouraging bed rest are the most frequently used prophylactic measures against the development of MPH. Frequently used treatment options for MPH include aggressive hydration, the EBP, oral caffeine, oral nonopioid analgesics, and bed rest. With the exception of a uniform blood volume (16-20 mL), procedural details of the EBP vary considerably among practitioners. The use of materials other than blood for epidural patch is uncommon.
◊ CONCLUSIONS:
Various measures, many poorly supported by the literature, are used prophylactically after UDP and in the treatment of MPH. Despite being nearly universally used as treatment of MPH, the EBP procedure itself remains largely nonstandardized.
◊ Reviewed by M. Vercauteren, MD. PhD.
Professor, Department of Anesthesia
Antwerp University Hospital, Antwerp, Belgium
This study revealed some remarkable findings such as the absence of protocols for the prevention and treatment of postdural puncture headache (PDPH) and epidural blood patches (EBP) in more than 80% of surveyed US centers. The high incidence of repeating the epidural at another interspace (i.e. more than 70%) in case of an accidental dural tap as well as the rapid removal of placed spinal catheters deserve closer attention. Furthermore, the volumes of blood injected during EBP may be considered as rather generous.
Although common policies might always be contested, in times of evidence-base medicine it is surprising how many anesthesiologists have developed discrepant practices.
In case of an accidental tap, a majority of studies have suggested to proceed with continuous spinal rather than performing the epidural at an adjacent interspace. This would risk the same problem while the existing hole may affect the epidural block. Placing an intrathecal catheter and keeping it in place for at least 24 hours may decrease the incidence of PDPH, the need for EBP or both [1-3]. According to this survey, in less than 20% of cases intrathecal catheters were introduced of which 70% were withdrawn either immediately after surgery or within the first 12 hours.
The way an EBP is performed is highly inconsistent. Blood volumes varied from 16 to 25 mL (as derived from 75% of the responses) and hence were larger than recommended (10-15 mL and 12-20 mL [4,5]). Studies using imaging techniques such as MRI and scintigraphy after injection of labeled red blood cells confirmed that most patients have a satisfactory dermatomal spread of 3 to 5 segments with 12-15 mL [6,7]. It is unclear whether higher volumes – even 45 and 58 mL have been reported [8,9] – are harmless or may cause compression of the dural sac, a cauda equina syndrome or increase the risk of hematoma, radiculopathy, and arachnoiditis [9].
The delay until ambulation after EBP was less than 60 min in 75% of responses although studies have suggested longer intervals to avoid any pressure on the dura and the clot formed as well as any Valsalva effect [10]. Is there any specific reason why these patients should be discharged so fast?
Too rapid ambulation may explain the low success rate of the first EBP which in some studies was less than the initial estimates exceeding 90%. These turned out to be too optimistic and overgenerous [4,11]. Especially in obstetric patients there may be a higher need for repeated EBP [11]. Although the survey did not aim at evaluating the effectiveness of EBP, the authors missed the opportunity to report the incidence of a prophylactic EBP and the use of the epidural catheter to perform the blood patch.
◊ References:
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[2] Dennehy KC, Rosaeg OP. Can J Anaesth 1998; 45: 42-5
[3] Paech M, Banks S, Gurman L. Int J Obstet Anesth 2001; 10: 162-7
[4] Duffy PJ, Crosby ET. The epidural blood patch. Resolving the controversies. Can J Anaesth 1999; 48: 878-86.
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[6] Szeinfeld M, Ihmeidan IH, Moser MM, Machado R, Klose KJ, Serafini AN. Epidural blood patch : evaluation of the volume and spread of blood injected into the epidural space. Anesthesiology 1986; 64: 820-2.
[7] Griffiths AG, Beards SC, Jackson A, Horsman EL. Visualization of extradural blood patch for post lumbar puncture headache by magnetic resonance imaging. Br J Anaesth 1993; 70: 223-5.
[8] Mehta B, Tarshis J. Repeated large-volume epidural blood patches for the treatmentof spontaneousintracranial hypotension. Can J Anaesth 2009; 56: 609-13
[9] Riley CA, Spiegel JE. Complications following large-volume epidural blood patches for postdural puncture headache. Lumbar subdural hematoma and arachnoiditis : initial cause or final effect ? J Clin Anesth 2009; 21: 355-9.
[10] Martin R, Jourdain S, Clairoux M, Tetrault J. Duration of decubitus position after epidural blood patch. Can J Anaesth 1994; 41: 23-5.
[11] Vercauteren M, Hoffmann VH, Mertens E, Sermeus L, Adriaensen HA. Seven-year review of requests for epidural blood patchesP for headache after dural puncture: referral patterns and the effectiveness of blood patches.Eur J Anaesthesiol. 1999; 16:298-303.
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