Anesth Analg 1999;88:962
© 1999 International Anesthesia Research Society
LETTERS TO THE EDITOR
The Influence of Epidural Needle Bevel on Spread of Sensory Blockade in the Laboring Parturient
Philip R. Bromage, MBBS, FFARCS, FRCPC
Department of Anaesthesia McGill University Montreal, Canada
Dr. Huffnagle et al. are to be commended on their frankness in reporting a 4.4% incidence of accidental dural puncture in the performance of epidural blockade (1). This is the highest incidence of three series published by one of the authors—2.6% in 1989 (2) and 4.2% in 1994 (3)—to now reach a ninefold increase above the level of 0.4%–0.5% that is achievable in a university-based program (4).
Although the title of their article relates to the effect of needle orientation on sensory spread, the remarkably high background incidence of 4.4% accidental dural puncture is cause for alarm and raises a number of questions relating to present developments in resident training and patient care while undermining the very credibility of epidural analgesia as an acceptable technique.
First, we must acknowledge that accidental dural puncture with a 17- or 18-gauge needle is not an innocuous event totally devoid of complications; that it has an incidence of <0.5% in properly trained hands and incidences >0.5% suggests that training methods in epidural analgesia should be reviewed and remedied (4).
Second, the underlying spinal cord may be placed in jeopardy from accidental dural puncture because the presumed vertebral level of spinal puncture is prone to a cephalad error of one or two spaces (5).
Third, the dural rent serves as a physical entrance to the subarachnoid space for any subclinical infection present in the epidural space.
Finally, under contemporary patterns of ultraearly postoperative hospital discharge, uncommon complications related to large bore dural puncture, such as subdural hematoma or meningitis, may suffer delayed diagnosis and serious neurologic sequelae.
The authors have performed a valuable service by publishing their findings at a time when the pressures for ultraearly hospital discharge have intensified the dangers arising from delayed complications of subarachnoid or epidural blockade. Perhaps the warnings implicit in their report may focus attention on the urgent need to review intradepartmental training methods in epidural blockade and to develop appropriate fast-track procedures to deal effectively with postanesthetic complications arising after ultraearly hospital discharge.
References
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Huffnagle SL, Norris MC, Arkoosh VA, et al. The influence of epidural needle bevel orientation on spread of sensory blockade in the laboring parturient. Anesth Analg 1998;87:326–30.[Abstract/Free Full Text]
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Norris MC, Leighton BL, DeSimone CA. Needle bevel direction and headache after inadvertent dural puncture. Anesthesiology 1989;70:729–31.[Web of Science][Medline]
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Norris MC, Grieco WM, Borkowski M, et al. Complications of labor analgesia: epidural versus combined spinal epidural techniques. Anesth Analg 1994;79:529–37.[Abstract/Free Full Text]
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Bromage PR. Epidural analgesia. Philadelphia: WB Saunders, 1978:191–6, 716–27.
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Van Gessel EF, Forster A, Gamulin Z. Continuous spinal anesthesia: where do spinal catheters go? Anesth Analg 1993;76:1004–7.[Abstract/Free Full Text]
Response
Suzanne Huffnagle, DO*, and
Mark C. Norris, MD
Departments of Anesthesiology
*Thomas Jefferson University Philadelphia, PA 19107
Washington University St. Louis, MO
We appreciate the opportunity to respond to Dr. Bromage’s comments. Although we agree with him about the implications of accidental dural puncture, we believe that his concerns about the risk of dural puncture in our teaching program are overstated. First, the 4.4% dural puncture rate in our current study (1) represents a single sample of our total patient population. Statistical analysis suggests that the true risk of dural puncture in our patients ranges from a respectable 1.2% to a horrendous 7.5%. He also notes that we reported a 4.2% risk of dural puncture in our earlier study (2). This figure, too, is somewhat misleading. The dural puncture rate was 4.2% among the 375 women who received "traditional" epidural analgesia, but, when the women who received combined spinal-epidural analgesia are included, the risk of accidental dural puncture is only 2.1% (95% confidence interval 1.2%–2.9%). Although these numbers are larger than Dr. Bromage’s goal of 0.4%–0.5%, they are comparable to the rates reported for other training programs (3,4).
We agree with Dr. Bromage that dural puncture with a 17- or 18-gauge needle is not innocuous. We closely observe our patients both in the hospital and after discharge and promptly treat any headaches with initially conservative (bed rest, caffeine, analgesics) and then more aggressive (epidural blood patch) therapies. We join with Dr. Bromage in emphasizing the importance of appropriate pre- and postdischarge care of our patients.
References
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Huffnagle SL, Norris MC, Arkoosh VA, et al. The influence of epidural needle orientation on spread of sensory blockade in the laboring parturient. Anesth Analg 1998;87:326–30.
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Norris MC, Grieco WM, Borkowski M, et al. Complications of labor analgesia: epidural versus combined spinal epidural techniques. Anesth Analg 1994;79:529–37.
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Richardson MG, Wissler R. Touhy needle bevel orientation during epidural catheter placement: effect on analgesic success during labor [abstract]. Anesthesiology 1996;85:A908.
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Birnbach DJ, Stein DJ, Hartman JK, et al. Complications of combined spinal epidural (CSE) compared with lumbar epidural analgesia [abstract]. Anesthesiology 1996;85:A860.
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