Newly Published
Perioperative Medicine  |   February 2020
Hydromorphone Unit Dose Affects Intraoperative Dosing: An Observational Study
Author Notes
  • From the Department of Anesthesiology and Perioperative Medicine (B.D.E., J.C.H., P.A.C., E.G., M.C.) and Medicine Statistics Core (T.G.), University of California, Los Angeles, Los Angeles, California.
  • Part of this work was presented at the Anesthesiology Annual Meeting, San Francisco, California, October 13, 2018.
    Part of this work was presented at the Anesthesiology Annual Meeting, San Francisco, California, October 13, 2018.×
  • Submitted for publication April 9, 2019. Accepted for publication January 2, 2020.
    Submitted for publication April 9, 2019. Accepted for publication January 2, 2020.×
  • Correspondence: Address correspondence to Dr. Cannesson: 757 Westwood Plaza Suite 3325, Los Angeles, California 90095. mcannesson@mednet.ucla.edu. Information on purchasing reprints may be found at www.anesthesiology.org or on the masthead page at the beginning of this issue. Anesthesiology’s articles are made freely accessible to all readers, for personal use only, 6 months from the cover date of the issue.
Article Information
Perioperative Medicine / Pain Medicine / Pharmacology / Opioid
Perioperative Medicine   |   February 2020
Hydromorphone Unit Dose Affects Intraoperative Dosing: An Observational Study
Anesthesiology Newly Published on February 10, 2020. doi:https://doi.org/10.1097/ALN.0000000000003176
Anesthesiology Newly Published on February 10, 2020. doi:https://doi.org/10.1097/ALN.0000000000003176
Abstract

Background: Although clinical factors related to intraoperative opioid administration have been described, there is little research evaluating whether administration is influenced by drug formulation and, specifically, the unit dose of the drug. The authors hypothesized that the unit dose of hydromorphone is an independent determinant of the quantity of hydromorphone administered to patients intraoperatively.

Methods: This observational cohort study included 15,010 patients who received intraoperative hydromorphone as part of an anesthetic at the University of California, Los Angeles hospitals from February 2016 to March 2018. Before July 2017, hydromorphone was available as a 2-mg unit dose. From July 1, 2017 to November 20, 2017, hydromorphone was only available in a 1-mg unit dose. On November 21, 2017, hydromorphone was reintroduced in the 2-mg unit dose. An interrupted time series analysis was performed using segmented Poisson regression with two change-points, the first representing the switch from a 2-mg to 1-mg unit dose, and the second representing the reintroduction of the 2-mg dose.

Results: The 2-mg to 1-mg unit dose change was associated with a 49% relative decrease in the probability of receiving a hydromorphone dose greater than 1 mg (risk ratio, 0.51; 95% CI, 0.40–0.66; P < 0.0001). The reintroduction of a 2-mg unit dose was associated with a 48% relative increase in the probability of administering a dose greater than 1 mg (risk ratio, 1.48; 95% CI, 1.11–1.98; P = 0.008).

Conclusions: This observational study using an interrupted time series analysis demonstrates that unit dose of hydromorphone (2 mg vs. 1 mg) is an independent determinant of the quantity of hydromorphone administered to patients in the intraoperative period.

Editor’s Perspective:

What We Already Know about This Topic:

  • Drug dosing during anesthesia should be determined by clinical factors

  • To the extent that clinicians might consider the amount of drug in a single-patient-use vial to be a unit dose, the amount of drug in vials might influence use

What This Article Tells Us That Is New:

  • The investigators used a natural experiment in which their institution switched from 2-mg vials of hydromorphone to 1-mg vials, and then back to 2-mg vials

  • Using a sophisticated segmented regression analysis, they show that patients were far more likely to be given 1 mg hydromorphone when smaller vials were provided

  • The contents of single-patient-use vials influences drug use and might be used to guide practice