///2017 Abstract Details
2017 Abstract Details2019-08-02T15:54:53-06:00

Intrathecal Hydromorphone for Post Cesarean Delivery Analgesia – Impact of Lowering the Dose on the Amount of Rescue Pain Medication

Abstract Number: T-50
Abstract Type: Original Research

Kyle N Jespersen MD1 ; H. Jane Huffnagle DO2; Suzanne L Huffnagle DO3; Michele M Mele MD4; John Wenzel MD5; Marc Torjman PhD6

Introduction:

Cesarean section (C/S) is usually performed under spinal using bupivacaine and intrathecal morphine (ITM). With the critical shortage of ITM in 2012, we empirically used 200-mcg intrathecal hydromorphone (ITH) and undertook a dose finding study. We found the minimum concentration of ITH to be 60-mcg and the ED 80 to be 130-mcg (1). This study assesses the effect this lower dose has had on post-operative medication usage.

Methods:

After IRB approval, a chart review was conducted to identify 120 matched patients who had primary or repeat C/S under spinal, 60 using 200-mcg ITH and 60 using 130-mcg ITH. The amount of post-operative oxycodone/acetaminophen (5-mg/325-mg), oxycodone, and morphine (via PCA) were converted to oral morphine mg equivalents and totaled for each patient's hospital stay (2). Ibuprofen and acetaminophen amounts were also tallied.

Statistical Analysis:

54 subjects per group were necessary for 80% power to detect a 15% difference in morphine mg equivalents. Statistical significance was determined using the Student t-test (age, LOS, BMI), Mann Whitney U (number C/S, MSO4 mg equivalents), Pearson Chi-Square (race).

Results:

We found no difference in post-operative opioid use (p=0.877), age, length of stay, or number of C/S per patient; BMI was higher in the 130-mcg group.

Discussion:

In light of our prior study's results (minimal dose, 60-mcg ITH, ED 80, 130-mcg), we have switched from 200-mcg ITH to 130-mcg. This study's goal was to validate the lower dose by comparing post-operative pain medication use before and after the change. We found no difference in opioid consumption and little variability in ibuprofen and acetaminophen use. This implies that a 130-mcg dose is clinically as effective as 200-mcg. Other literature suggests 130-mcg ITH may be too high and an additional dose finding study may be indicated (3, 4).

As with any chart review, we could have introduced selection bias; our sample may not be representative of, or generalizable to, our whole population. We hoped to lessen this using a relatively large sample size and group matching of patients. We acknowledge the difference in BMI, however long acting IT opioids are not routinely dosed based on patient weight.

References:

(1) ASA Abstract A-3109,2015

(2) Calculating Total Daily Dose of Opioids for Safer Usage. http://www.ced.gov/drugoverdose/pdf/calculating_total_daily_dose-a.pdf

(3) Beatty NC, et al. JCA 2013;25:379-383

(4) Sviggum HP, et al. A&A 2016;123:690-7



SOAP 2017