In this episode, I’ll discuss how to predict hypotension from dexmedetomidine.
Dexmedetomidine is a popular sedative for use in critically ill patients. Hypotension is a common side effect that may limit the dose or even use of dexmedetomidine in critically ill patients. Being able to predict hypotension in advance can help clinicians choose a different sedative approach or increase patient monitoring.
At least two retrospective studies have looked at factors that might predict hypotension from dexmedetomidine. The first was published in International Journal of Critical Illness & Injury Science September 2016 and the 2nd was published as an abstract in Critical Care Medicine in 2018.
The 2016 study was a retrospective study covering 4 ICUs within a single center. Patients who were hypotensive at baseline were excluded. 283 patients were analyzed. The primary endpoint was the finding of hypotension (MAP < 60 mmHg).
The 2018 study was a retrospective cohort study of patients with a primary cardiac diagnosis who received dexmedetomidine in a single CVICU. 276 patients were analyzed. The primary endpoint was the finding of hypotension (MAP < 60 mmHg).
In both studies, hypotension occurred in about 40% of patients.
In the CVICU study, univariate analysis showed that patients with a ST-elevation myocardial infarction, longer duration of dexmedetomidine infusion, or an increased number of rate changes were significantly more likely to develop hypotension.
In the ICU study after multi-variate analysis, the risk factors associated with dexmedetomidine-related hypotension were:
1. Baseline MAP
2. APACHE II score
3. History of coronary artery disease
Despite the ICU study being a single-center study, several elements suggest the results may apply to other ICUs.
- No patient received a bolus of dexmedetomidine. The one mcg/kg over 10-minute bolus of dexmedetomidine is still listed in prescribing information as a potential treatment option. However, it is not commonly used in clinical practice due to excessive side effects.
- The dose range for dexmedetomidine was up to 1.4 mcg/kg/hour which is a commonly used maximum dose range. However, only one-third of the patients in the study received a dose >1 mcg/kg/hour.
- Excessive titration (dose adjustment more frequent than every 30 minutes) was similar in both the hypotensive and non-hypotensive group (15.4% vs. 19.8%).
Because the CVICU study was only published as an abstract, similar detail on the external validity is unknown.
Members of my Hospital Pharmacy Academy have access to practical training from a pharmacist’s point of view on using dexmedetomidine in critical care. This is in addition to many other resources to help in your practice. To get immediate access, go to pharmacyjoe.com/academy.
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