Considerations on Midodrine Use in Resolving Septic Shock

Putting midodrine on the MAP: An approach to liberation from intravenous vasopressors in vasodilatory shock

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PURPOSE

Prolonged duration of intravenous (IV) vasopressor dependence in critically ill adult patients with vasodilatory shock results in increased length of stay in both the intensive care unit (ICU) and hospital, translating to higher risk of infection, delirium, immobility, and cost. Acceleration of vasopressor liberation can aid in reducing these risks. Midodrine is an oral α1-adrenergic receptor agonist that offers a potential means of liberating patients from IV vasopressor therapy. This clinical review summarizes primary literature and proposes a clinical application for midodrine in the recovery phase of vasodilatory shock.

SUMMARY

Five studies with a total of over 1,000 patients conducted between 2011 and 2021 were identified. In observational studies, midodrine administration was demonstrated to lead to faster time to liberation from IV vasopressor therapy and shorter ICU length of stay in patients recovering from vasodilatory shock. These findings were not replicated in a prospective, multicenter, randomized controlled trial. In this review, literature evaluating midodrine use for IV vasopressor liberation is summarized and study limitations are discussed.

CONCLUSION

On the basis of this review of current literature, recommendations are provided on selecting appropriate candidates for adjunctive midodrine in the recovery phase of vasodilatory shock and considerations are discussed for safely and effectively initiating, titrating, and discontinuing therapy.

Midodrine as an Adjuvant to Intravenous Vasopressor Agents in Adults With Resolving Shock: Systematic Review and Meta-Analysis

PURPOSE

To evaluate the effects of midodrine in addition to intravenous vasopressor therapy on outcomes in adults recovering from shock.

MATERIALS AND METHODS

PubMed, Scopus, Clinicaltrials.gov, and published abstracts were searched from inception to November 2018 for studies comparing outcomes in shock after midodrine initiation versus no midodrine.

RESULTS

Three studies with 2533 patients were included. Patients in whom midodrine was added to intravenous vasopressor therapy compared to intravenous vasopressor therapy alone experienced similar intensive care unit (ICU; mean difference [MD]: 1.38 days, 95% confidence interval [CI]: -3.48 to 6.23, I² = 93%) and hospital lengths of stay (MD: 4.37 days, 95% CI: -3.45 to 12.19, I² = 93%) and intravenous vasopressor duration after midodrine initiation (MD: 7.28 days, 95% CI: -0.86 to 15.41, I² = 97%). Mortality was similar between groups (odds ratio: 0.74, 95% CI: 0.44-1.27, I² = 65%). Qualitative assessment of reporting biases revealed minimal location bias, moderate selective outcome reporting bias, no selective analysis reporting bias, and no conflict of interest bias.

CONCLUSIONS

Midodrine had no effect on ICU or hospital length of stay. These results were highly susceptible to the study heterogeneity and availability. Future investigation into standardized initiation of midodrine at an adequate dosage with an expedited titration strategy is needed in order to assess the utility of this strategy in shock management.

Norepinephrine and Vasopressin Compared With Norepinephrine and Epinephrine in Adults With Septic Shock

Background: The optimal adjuvant vasopressor to norepinephrine in septic shock remains controversial. Objective: To compare durations of shock-free survival between adjuvant vasopressin and epinephrine. Methods: A retrospective, single-center, matched cohort study of adults with septic shock refractory to norepinephrine was conducted. Patients receiving norepinephrine not at target mean arterial pressure (MAP; 65 mm Hg) were initiated on vasopressin or epinephrine to raise MAP to target. Vasopressin-exposed patients were matched to epinephrine-exposed patients using propensity scores. Mortality outcomes were examined using multivariable Poisson regression with robust variance estimation. Results: Of 166 patients, 96 (entire cohort) were included in the propensity score-matched cohort. Shock-free survival durations in the first 7 days were similar between epinephrine- and vasopressin-exposed patients in the matched cohort (median = 13.2 hours, interquartile range [IQR] = 0-121.0, vs median = 41.3 hours, IQR = 0-125.9; P = 0.51). Seven- and 28-day mortality rates were similar in the matched cohort (7-day: 47.9% vs 39.6%, P = 0.35; 28-day: 56.3% vs 58.3%, P = 0.84). Mortality rates were similar between epinephrine- and vasopressin-exposed patients in propensity score-matched regression models with and without adjustments at 7 (relative risk [RR] = 1.28, 95% CI = 0.92-1.79; RR = 1.21, 95% CI = 0.81-1.81) and 28 days (RR = 1.04, 95% CI = 0.81-1.34; RR = 0.96, 95% CI = 0.69-1.34). Conclusion and Relevance: Shock-free survival durations were similar in matched epinephrine- and vasopressin-exposed groups. Adjuvant epinephrine or vasopressin alongside norepinephrine to raise MAP to target requires further investigation.

Discontinuation of Vasopressin Before Norepinephrine in the Recovery Phase of Septic Shock

BACKGROUND

Guidance for the discontinuation of vasopressors in the recovery phase of septic shock is limited. Norepinephrine is more easily titrated; however, septic shock is a vasopressin deficient state, which exogenous vasopressin endeavors to resolve. Discontinuation of vasopressin before norepinephrine may result in clinically significant hypotension.

METHODS

This retrospective, cohort study compared discontinuation of norepinephrine and vasopressin in medically, critically ill patients in the recovery phase of septic shock from May 2014 to June 2016. Difference in clinically significant hypotension after norepinephrine or vasopressin discontinuation was evaluated with χ² test. Linear regression was performed, examining the effect of agent discontinuation on clinically significant hypotension. Baseline variables were examined for a bivariate relationship with clinically significant hypotension; those with P < .2 were included in the model.

RESULTS

Vasopressin was discontinued first or last in 62 and 92 patients, respectively. Sequential Organ Failure Assessment scores at 72 hours (7.9 vs 7.6, P = .679) were similar. In unadjusted analysis, when vasopressin was discontinued first, more clinically significant hypotension developed (10.9% vs 67.8%, P < .001). There was no difference in intensive care unit (174 vs 216 hours, P = .178) or hospital duration (470 vs 473 hours, P = .977). In adjusted analyses, discontinuing vasopressin first was associated with increased clinically significant hypotension (odds ratio [OR]: 13.837, 95% confidence interval [CI]: 3.403-56.250, P < .001) but not in-hospital (OR: 0.659, 95% CI: 0.204-2.137, P = .488) or 28-day mortality (OR: 0.215, 95% CI: 0.037-1.246, P = .086).

CONCLUSION

Adult patients receiving norepinephrine and vasopressin in the resolving phase of septic shock may be less likely to develop clinically significant hypotension if vasopressin is the final vasopressor discontinued.