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LETTERS TO THE EDITOR

Epidural Analgesia After Dural Puncture

Department of Anesthesia University of Manitoba Winnipeg, Manitoba, Canada

Hebl et al. (1) found that the success rate of epidural analgesia and anesthesia in patients who have undergone dural puncture to be similar to that of patients who have undergone two previous epidural anesthetics. Those findings were different from an earlier report by Ong et al. (2), in which epidural analgesia was often impaired after dural puncture with and without subsequent blood patch. The contrary results may be explained by differences in patient groups and technical differences in identifying the epidural space.

The patients of Ong et al. (2) were all parturients who had dural puncture with 16-gauge Tuohy needles. Seventy-one of the 87 patients for Hebl et al. (1) had dural puncture for spinal anesthesia. The spinal anesthesia was probably performed with finer needles.

The mean ages of patients of Ong et al. (2) ranged from 22 to 27 years, whereas the mean ages of patients of Hebl et al. (1) ranged from 34 to 40 years.

The most common technique for identification of the epidural space for Ong et al. (2) was by loss of resistance to air. Hebl et al. (1) used the saline loss of resistance technique.

Further studies controlling the variations in the study patients and the loss of resistance techniques for identification of epidural space may explain the different observations in the two studies.

References

1. Hebl JR, Horlocker TT, Chantigian RC, Schroeder DR. Epidural anesthesia and analgesia are not impaired after dural puncture with or without epidural blood patch. Anesth Analg 1999;89:390–4.[Abstract/Free Full Text]
2. Ong BY, Graham CR, Ringaert KR, et al. Impaired epidural analgesia after dural puncture with and without subsequent blood patch. Anesth Analg 1990;70:76–9.[Abstract/Free Full Text]

Response

Department of Anesthesiology Mayo Clinic Rochester, MN 55905

We would like to thank Dr. Ong for his interest in our recent article addressing subsequent epidural anesthesia and analgesia in patients who have a history of dural puncture, with or without epidural blood patch (1). In his letter to the editor, Dr. Ong suggested that differences in patient age, needle size during dural puncture, and technique of epidural needle placement (air versus saline loss of resistance) may account for the significant difference in epidural success rates reported in our investigation (95%) compared with those of Ong et al. (65%) (2). Although differences in needle size (during dural puncture) and age existed between the two studies, a review of the current literature provides no evidence that these variables contribute to epidural success rates. An additional study by Blanche et al. (3) had similar results as ours, namely that previous dural puncture did not affect the efficacy of subsequent epidural analgesia. They reported a subsequent epidural success rate of 91% in parturients whose age and size of dural puncture were similar to those of Ong et al. (2).

Finally, Dr. Ong has suggested that their loss of resistance technique with air (as compared with saline in our parturients) may have contributed to their lower subsequent epidural success rates. Although this may explain subsequent epidural failure in patients who have undergone recent (within days) epidural needle placement with air (4), it seems unlikely that this would have any long-term implications. Currently, there is no evidence that suggests epidural needle placement with small volumes of air has any significance on subsequent epidural efficacy several months or years later.

Therefore, it is improbable that the differences in subsequent epidural success rates can be attributed to needle size, age, or technique. As a result, we conclude that previous dural puncture, with or without epidural blood patch, does not affect the success rate of subsequent epidural anesthesia or analgesia.

References

1. Hebl JR, Horlocker TT, Chantigian RC, Schroeder DR. Epidural anesthesia and analgesia are not impaired after dural puncture with or without epidural blood patch. Anesth Analg 1999;89:390–4.
2. Ong BY, Graham CR, Ringaert KR, et al. Impaired epidural analgesia after dural puncture with and without subsequent blood patch. Anesth Analg 1990;70:76–9.
3. Blanche R, Eisenach JC, Tuttle R, Dewan DM. Previous wet tap does not reduce success rate of labor epidural analgesia. Anesth Analg 1994;79:291–4.[Abstract/Free Full Text]
4. Dalens B, Bazin J, Haberer J. Epidural bubbles as a cause of incomplete analgesia during epidural anesthesia. Anesth Analg 1987;66:679–83.[Free Full Text]

This Article Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Email this article to a colleague Similar articles in this journal Similar articles in Web of Science Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Request Permissions Citing Articles Citing Articles via Google Scholar Google Scholar Articles by Ong, B. Articles by Chantigian, M. R. C. Search for Related Content PubMed PubMed Citation Articles by Ong, B. Articles by Chantigian, M. R. C.