///2014 Abstract Details
2014 Abstract Details2019-07-18T14:34:47-06:00

Optimal dosing of spinal anesthesia for cesarean delivery using intrathecal catheters

Abstract Number: S-43
Abstract Type: Original Research

Katherine Hoctor MD1 ; Daria Moaveni MD2; Jennifer Hochman-Cohn MD3; J. Sudharma Ranasinghe MD4; Allison Lee MD5; David J Birnbach MD, MPH6


Placement of intrathecal catheters (ITC) after accidental dural puncture is practiced by many anesthesiologists.[1] Currently, there is no literature defining the optimal dose of bupivacaine for cesarean delivery using an ITC. Previous studies evaluating local anesthetic dosing for anesthesia given through a spinal needle suggest that low dose spinal bupivacaine provides effective surgical anesthesia with a lower incidence of spinal side effects.[2, 3] Optimal dosing of spinal anesthesia via an ITC has not been reported. We place approximately 25 ITC per year to provide anesthesia for high-risk parturients and have collected data on the dosing of these ITCs for cesarean deliveries.


Our aim was to determine if low doses of bupivacaine administered through ITC provides effective surgical anesthesia for cesarean delivery while decreasing the incidence of side effects compared to higher doses of bupivacaine.


As a pilot study, we collected data on all ITC dosed for cesarean delivery:

1. Dose of 0.75% hyperbaric bupivacaine required to obtain an initial T4-T6 level:

a. Low dose group: 0.8 ml (6 mg) or less

b. High dose group: greater than 0.8 ml (6 mg)

2. Need to re-dose the catheter within one hour of initial dose (inadequate duration)

3. Need to re-dose the catheter within 15 minutes of initial dose (inadequate initial block)

4. Frequency of spinal anesthesia side effects:

a. Incidence of hypotension from initial spinal dose

b. Administration of vasopressors

c. Incidence of nausea and/or vomiting


Data from 28 patients with intraoperative ITC were collected. Fourteen patients were in the low dose group and 14 patients in the high dose group.

1. All 28 patients achieved a T4 +/-1 anesthetic level.

2. 57% of the low dose group vs 36% of the high dose group needed supplemental dosing within one hour .

3. Intraoperative pain occurring less than 15 minutes after the initial spinal dose occurred in 2 patients, both in the low dose group.

4. Side effects- there were no statistically significant differences between the low and high dose groups.


The results of this pilot study suggest that low dose spinal bupivacaine (0.8ml or less), can achieve effective surgical anesthesia. However, the low dose group experienced more intraoperative discomfort, needed more top-ups, and had no reduction of hypotension or nausea and vomiting. These data suggest that higher ITC doses may be beneficial, especially given that re-dosing of the ITC near the end of the surgery may prolong PACU stays. Based on this pilot, we plan to perform a prospective, randomized dose response study to determine the optimal dosing of an ITC for cesarean delivery.


1. Baraz, R. et al. Anesthesia, 2005. 60: p. 673-9.

2. Roofthooft, E. et al. Curr Opin Anaesthesiol, 2008. 21: p. 259-62.

3. Arzola, C. et al. Br J Anaesth, 2011. 107: p. 308-18.

4. Tamilselvan, P. et al. Anesth Analg, 2009. 109: p. 1916-21.

SOAP 2014