///2019 Abstract Details
2019 Abstract Details2019-07-13T07:45:15-05:00

Epidural test dose practices in current day obstetric anesthesia practice: A literature review

Abstract Number: T2D-427
Abstract Type: Original Research

Yahui Tammy Symons MD, FRCPC1 ; Magdalena Terlecki MD2; Indu Singh MD, FRCPC3; Ian McConachie FRCA, FRCP4

Background: The ideal epidural test dose should allow the detection of a malpositioned catheter, be readily available, safe, and effective, with high sensitivity and low specificity.1 The classical intrathecal and intravenous test dose has been proposed as 45 mg of lidocaine with 15 mcg of epinephrine.2,3 There is no consensus regarding the content and nature of the ideal test dose in obstetric anesthesia. This literature review aimed to clarify current epidural test dose practices in recent years as published in a leading Obstetric Anesthesia journal.

Methods: A literature review of all articles published in the International Journal of Obstetric Anesthesia from 2009 to 2018 was conducted. Articles that mentioned use of an epidural test dose were identified and data pertaining to type and dose of local anesthetic, volume, presence of additives, and method of administration were reviewed.

Results: In all issues published in the last 10 years, an epidural test dose was mentioned in a total of 42 papers. Of these, 36 articles went into detail regarding type and nature of the test dose. We have included 42 test doses as described in these studies. The three most commonly used local anesthetics were lidocaine in 27 of cases (64.3%) followed by ropivacaine in 8 (19.0%), and bupivacaine in 7 (16.7%). Dose of lidocaine used ranged from 40-60mg. Doses of ropivacaine ranged from 5.1-50mg and bupivacaine from 5-20mg. Levobupivacaine was used in 2 articles (4.8%) at doses of 6.5mg and 15mg. Chloroprocaine was used in 1 case (2.4%) at a dose of 60mg. Epinephrine was included in the test dose in 17 articles (40.4%) and 6 included a narcotic (14.3%). Separate intrathecal and intravascular test doses were performed in 2 studies (4.8%).

Discussion: Our findings suggest that there is no consensus amongst obstetric anesthetists regarding the ideal test dose. Lidocaine is the most commonly used local anesthetic, but there is significant variation in use of other local anesthetics and in the doses chosen. A widely used obstetric anesthesia reference text cites lidocaine 40-60mg and bupivicaine 7.5mg as acceptable intrathecal test doses, with the addition of epinephrine to allow for combined intrathecal and intravenous test dosing.1 Intravenous test dose without epinephrine would require lidocaine 100mg, bupivacaine 25mg, or chloroprocaine 100mg. Based on our findings it would appear that most authors administer an intrathecal test dose only, and test doses of local anesthetics not listed in the reference text are in use. Finally, some authors reported performing a test dose but did not elaborate on further details. Improved documentation going forward is important, as well as further research to determine the ideal test dose.

References:

1. Chestnut's Obstetric Anesthesia: Principles and Practice. 2014 Elsevier Health Sciences.

2. Survey of Anesthesiology 1982;26(5):306-7.

3. Journal of clinical anesthesia 2003;15(6):474-7.

SOAP 2019