Determination of ED90 of Intrathecal Lidocaine for Adequate Anesthesia for Elective Cervical Cerclage Surgery

Summary

Cervical incompetence complicates approximately 1 in 500 pregnancies . Those women with cervical incompetence are at risk for second trimester spontaneous abortion and preterm labor. Cervical cerclage reduces these risks but must be performed under general or neuraxial anesthesia. Some anesthesiologists prefer neuraxial anesthesia, as it reduces fetal exposure to medications and avoids the risks associated with loss of maternal airway reflexes under general anesthesia. Spinal anesthesia, in particular, has the added advantage of being technically simple while still providing a rapid, dense sensory block. For cerclage placement, patients require a sensory block from the T10 to S4 dermatome in order to cover sensation from the cervix as well as the vagina and perineum. Patients presenting for cerclage under spinal anesthesia pose a dosing challenge given the physiologic changes associated with pregnancy. As women progress with their pregnancy, they require lower doses of intrathecal local anesthetic to achieve similar block level. Multiple studies have demonstrated that these changes start during the second trimester. Inadequate sensory coverage with a spinal anesthetic typically necessitates conversion to general anesthesia, causing additional time wasted and added risk to the patient and fetus. Anecdotally, this is the reason why some anesthesiologists choose general anesthesia for patients undergoing cerclage over a spinal anesthetic. As there is currently no literature determining the correct dosage for these patients, we propose a dose-response study to determine the ED90 of intrathecal lidocaine for adequate anesthesia for elective cervical cerclage placement.The findings of this study will help determine the minimum dose of intrathecal lidocaine necessary to provide adequate spinal anesthesia for cervical cerclage for 90% of women. This will help decrease the frequency of inadequate anesthesia for cervical cerclage.

Timeline

Start

2015-10

Primary completion

2016-08

Completion

2016-08

Outcome

Outcome not reported

Stopped: “planned surgical procedures decreased”

Publications

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• Background Lee GY, Kim CH, Chung RK, Han JI, Kim DY. Spread of subarachnoid sensory block with hyperbaric bupivacaine in second trimester of pregnancy. J Clin Anesth. 2009 Nov;21(7):482-5. doi: 10.1016/j.jclinane.2008.12.018.
• Background Lee MH, Son HJ, Lee SH, Lee JH, Chung MH, Choi YR, Choi EM. Comparison of spread of subarachnoid sensory block and incidence of hypotension in early and late second trimester of pregnancy. Korean J Anesthesiol. 2013 Oct;65(4):322-6. doi: 10.4097/kjae.2013.65.4.322. Epub 2013 Oct 24.
• Background Pace NL, Stylianou MP. Advances in and limitations of up-and-down methodology: a precis of clinical use, study design, and dose estimation in anesthesia research. Anesthesiology. 2007 Jul;107(1):144-52. doi: 10.1097/01.anes.0000267514.42592.2a.
• Background Choi PT, Galinski SE, Takeuchi L, Lucas S, Tamayo C, Jadad AR. PDPH is a common complication of neuraxial blockade in parturients: a meta-analysis of obstetrical studies. Can J Anaesth. 2003 May;50(5):460-9. doi: 10.1007/BF03021057.

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