Perceptions regarding vasopressin use and practices in septic shock, and cost containment strategies

Optimizing Vasopressin Use and Initiation Timing in Septic Shock: A Narrative Review

TOPIC IMPORTANCE

This review discusses the rationale for vasopressin use, summarizes the results of clinical trials evaluating vasopressin, and focuses on the timing of vasopressin initiation to provide clinicians guidance for optimal adjunctive vasopressin initiation in patients with septic shock.

REVIEW FINDINGS

Patients with septic shock require vasoactive agents to restore adequate tissue perfusion. After norepinephrine, vasopressin is the suggested second-line adjunctive agent in patients with persistent inadequate mean arterial pressure. Vasopressin use in practice is heterogeneous likely because of inconsistent clinical trial findings, the lack of specific recommendations for when it should be used, and the high drug acquisition cost. Despite these limitations, vasopressin has demonstrated price inelastic demand, and its use in the United States has continued to increase. However, questions remain regarding optimal vasopressin use in patients with septic shock, particularly regarding patient selection and the timing of vasopressin initiation.

SUMMARY

Experimental studies evaluating the initiation timing of vasopressin in patients with septic shock are limited, and recent observational studies have revealed an association between vasopressin initiation at lower norepinephrine-equivalent doses or lower lactate concentrations and lower mortality.

Vasopressin in Sepsis and Other Shock States: State of the Art

This review of the use of vasopressin aims to be comprehensive and highly practical, based on the available scientific evidence and our extensive clinical experience with the drug. It summarizes controversies about vasopressin use in septic shock and other vasodilatory states. Vasopressin is a natural hormone with powerful vasoconstrictive effects and is responsible for the regulation of plasma osmolality by maintaining fluid homeostasis. Septic shock is defined by the need for vasopressors to correct hypotension and lactic acidosis secondary to infection, with a high mortality rate. The Surviving Sepsis Campaign guidelines recommend vasopressin as a second-line vasopressor, added to norepinephrine. However, these guidelines do not address specific debates surrounding the use of vasopressin in real-world clinical practice.

Adjusting vasopressin availability and formulation: A cost-savings initiative

Disclaimer

In an effort to expedite the publication of articles related to the COVID-19 pandemic, AJHP is posting these manuscripts online as soon as possible after acceptance. Accepted manuscripts have been peer-reviewed and copyedited, but are posted online before technical formatting and author proofing. These manuscripts are not the final version of record and will be replaced with the final article (formatted per AJHP style and proofed by the authors) at a later time.

Purpose

The increase in vasopressin price has required many healthcare systems to consider cost-saving strategies. To combat rising medication costs, our institution changed formulations from 50 units/250 mL to 20 units/100 mL and removed vasopressin from automated dispensing cabinets (ADCs).

Methods

This retrospective review occurred at a 545-bed academic medical center with 97 adult intensive care unit beds. Adult patients receiving a continuous vasopressin infusion were included with no exclusion criteria. A 1-month period was assessed before and after changing the formulation (pre and post groups, respectively). Duplicate bags compounded by pharmacy and bedside teams were also assessed in the pre group. The primary outcome was the estimated annual cost savings due to formulation change with a secondary outcome of estimated annual cost savings due to removal of vasopressin from ADCs. Each 20-unit vial of vasopressin cost $183.21 (wholesale acquisition cost) at the time of the study.

Results

In the pre group, 39 patients requiring a vasopressin infusion were allocated an average of 2 bags each costing $1,099.26 per patient. In the post group, 41 patients required an average of 4 bags each costing $732.84 per patient. With respect to the primary outcome, a savings of $366.42 per patient and an average of 40 patients per month would lead to an annual cost savings of $175,881.60. Secondary outcome analysis identified 9 duplicate bags prepared in the pre group; therefore, removal of vasopressin from ADCs is estimated to provide additional cost savings of $59,360.04. The estimated annual cost savings from both initiatives is $235,241.64.

Conclusion

Changing the vasopressin formulation and removing it from ADCs resulted in a significant cost savings to the health system.

Association Between Vasopressin Rebranding and Utilization in Patients With Septic Shock

OBJECTIVES

Vasopressin is suggested as an adjunct to norepinephrine in patients with septic shock. However, after vasopressin was rebranded in November 2014, its cost exponentially increased. Utilization patterns of vasopressin after its rebranding are unclear. The objective of this study was to determine if there is an association between the rebranding of vasopressin in November 2014 and its utilization in vasopressor-dependent patients with severe sepsis or septic shock.

DESIGN

Retrospective, multicenter, database study between January 2010 and March 2017.

SETTING

Premier Healthcare Database hospitals.

PATIENTS

Adult patients admitted to an ICU with severe sepsis or septic shock, who received at least one vasoactive agent for two or more calendar days were included.

INTERVENTIONS

The proportion of patients who received vasopressin and vasopressin cost was assessed before and after rebranding, and evaluated with segmented regression.

MEASUREMENTS AND MAIN RESULTS

Among 294,733 patients (mean age, 66 ± 15 yr), 27.8% received vasopressin, and ICU mortality was 26.5%. The proportion of patients receiving vasopressin was higher after rebranding (31.2% postrebranding vs 25.8% prerebranding). Before vasopressin rebranding, the quarterly proportion of patients who received vasopressin had an increasing slope (prerebranding slope 0.41% [95% CI, 0.35-0.46%]), with no difference in slope detected after vasopressin rebranding (postrebranding slope, 0.47% [95% CI, 0.29-0.64%]). After vasopressin rebranding, mean vasopressin cost per patient was higher ($527 ± 1,130 vs $77 ± 160), and the quarterly slope of vasopressin cost was higher (change in slope $77.18 [95% CI, $75.73-78.61]). Total vasopressin billed cost postrebranding continually increased by ~$294,276 per quarter from less than $500,000 in Q4 2014 to over $3,000,000 in Q1 2017.

CONCLUSIONS

After vasopressin rebranding, utilization continued to increase quarterly despite a significant increase in vasopressin cost. Vasopressin appeared to have price inelastic demand in septic shock.

The order of vasopressor discontinuation and incidence of hypotension: a retrospective cohort analysis

The optimal order of vasopressor discontinuation during shock resolution remains unclear. We evaluated the incidence of hypotension in patients receiving concomitant vasopressin (VP) and norepinephrine (NE) based on the order of their discontinuation. In this retrospective cohort study, consecutive patients receiving concomitant VP and NE infusions for shock admitted to intensive care units were evaluated. The primary outcome was hypotension incidence following discontinuation of VP or NE (VP1 and NE1 groups, respectively). Secondary outcomes included the incidence of acute kidney injury (AKI) and arrhythmias. Subgroup analysis was conducted by examining outcomes based on the type of shock. Of the 2,035 included patients, 952 (46.8%) were VP1 and 1,083 (53.2%) were NE1. VP1 had a higher incidence of hypotension than NE1 (42.1% vs. 14.2%; P < 0.001), longer time to shock reversal (median: 2.5 vs. 2.2 days; P = .009), higher hospital [29% (278/952) vs. 24% (258/1083); P = .006], and 28-day mortality [37% (348/952) vs. 29% (317/1,083); P < 0.001] when compared with the NE1 group. There were no differences in ICU mortality, ICU and hospital length of stay, new-onset arrhythmia, or AKI incidence between the two groups. In subgroup analyses based on different types of shock, similar outcomes were observed. After adjustments, hypotension in the following 24 h and 28-day mortality were significantly higher in VP1 (Odds ratios (OR) 4.08(3.28, 5.07); p-value < .001 and 1.27(1.04, 1.55); p-value < .001, respectively). Besides, in a multivariable model, the need for renal replacement therapy (OR 1.68 (1.34, 2.12); p-value < .001) was significantly higher in VP1. Among patients with shock who received concomitant VP and NE, the VP1 group was associated with a higher incidence of hypotension in comparison with NE1. Future studies need to validate our findings and their impact on clinical outcomes.

Hemodynamic Response to Vasopressin Dosage of 0.03 Units/Min vs. 0.04 Units/Min in Patients With Septic Shock

BACKGROUND

Arginine vasopressin (AVP) is suggested as an adjunct to norepinephrine in patients with septic shock. Guidelines recommend an AVP dosage up to 0.03 units/min, but 0.04 units/min is commonly used in practice based on initial studies. This study was designed to compare the incidence of hemodynamic response between initial fixed-dosage AVP 0.03 units/min and AVP 0.04 units/min.

METHODS

This retrospective, multi-hospital health system, cohort study included adult patients with septic shock receiving AVP as an adjunct to catecholamine vasopressors. Patients were excluded if they received an initial dosage other than 0.03 units/min or 0.04 units/min, or AVP was titrated within the first 6 hours of therapy. The primary outcome was hemodynamic response, defined as a mean arterial pressure ≥65 mm Hg and a decrease in catecholamine dosage at 6 hours after AVP initiation. Inverse probability of treatment weighting (IPTW) based on the propensity score for initial AVP dosage receipt was utilized to estimate adjusted exposure effects.

RESULTS

Of the 1536 patients included in the observed data, there was a nearly even split between initial AVP dosage of 0.03 units/min (n = 842 [54.8%]) and 0.04 units/min (n = 694 [45.2%]). Observed patients receiving AVP 0.03 units/min were more frequently treated at the main campus academic medical center (96.3% vs. 52.2%, p < 0.01) and in a medical intensive care unit (87.4% vs. 39.8%, p < 0.01). The IPTW analysis included 1379 patients with achievement of baseline covariate balance. There was no evidence for a difference between groups in the incidence of hemodynamic response (0.03 units/min 50.0% vs. 0.04 units/min 53.1%, adjusted relative risk 1.06 [95% CI 0.94, 1.20]).

CONCLUSIONS

Initial AVP dosing varied by hospital and unit type. Although commonly used, an initial AVP dosage of 0.04 units/min was not associated with a higher incidence of early hemodynamic response to AVP in patients with septic shock.

Abrupt Discontinuation Versus Down-Titration of Vasopressin in Patients Recovering from Septic Shock

PURPOSE

To compare patient outcomes based on management of arginine vasopressin (AVP) during the recovery phase of septic shock (abrupt vs. tapering discontinuation).

PATIENTS AND METHODS

Multicenter, retrospective cohort study of patients receiving AVP with concomitant norepinephrine for septic shock. Primary outcome measure was time to intensive care unit (ICU) discharge (from decision to titrate or stop AVP). Secondary outcomes included ICU and hospital mortality, and incidence of hypotension.

RESULTS

A total of 958 (73%) abrupt discontinuation and 360 (27%) down-titration patients were included. Patient characteristics and septic shock treatment courses were similar between groups. Median time to ICU discharge was similar between abrupt discontinuation (7.9 days, 95% CI 7.2-8.7 days) and tapered patients (7.3 days, 95% CI 6.3-9.3 days, P = 0.60). After controlling for baseline discrepancies, down-titration was not an independent predictor of time to ICU discharge (HR = 0.99, 95% CI: 0.85-1.15, P = 0.91). There was no difference in ICU mortality (21.8% vs. 18.0%, P = 0.13) or hospital mortality (28.9% vs. 31.1%, P = 0.44). Although incidence of hypotension was similar (39.7% vs. 41.7%, P = 0.53), patients in the down-titration group more frequently required an escalation of AVP dose (5.7% vs. 11.1%, P < 0.001). Median AVP duration was shorter in the abrupt discontinuation group (1.4 days [IQR: 0.6-2.6 days] vs. 1.8 days [IQR: 1.1-3.2 days], P < 0.001).

CONCLUSIONS

A difference in time to ICU discharge was not detected between abrupt AVP discontinuation and down-titration in patients recovering from septic shock. In patients recovering from septic shock, abrupt discontinuation of AVP appears to be safe and may lead to shortened AVP duration.

Narrative Review of Controversies Involving Vasopressin Use in Septic Shock and Practical Considerations

Objective: To summarize literature evaluating vasopressin use, focusing on clinical controversies regarding initiation, dosing, and discontinuation and interaction of vasopressin with other therapies in septic shock patients. Data Sources: A PubMed English-language literature search (January 2008 to December 2019) was performed using these terms: arginine vasopressin, septic, shock, and sepsis. Citations, including controlled trials, observational studies, review articles, guidelines, and consensus statements, were reviewed. Study Selection and Data Extraction: Relevant clinical data focusing on specific controversial questions regarding the utility of vasopressin in patients with septic shock were narratively summarized. Data Synthesis: Current literature does not strongly support the use of vasopressin as a first-line initial therapy for septic shock. Additionally, there are conflicting data for weight-based dosing of vasopressin in overweight patients. Evidence for vasopressin renal protection and interaction with corticosteroids is minimal. However, vasopressin has the ability to reduce catecholamine requirements in septic shock patients and may provide a mortality benefit in specific subgroups. Discontinuation of vasopressin last, not second to last, in resolving septic shock may reduce hypotension development. Relevance to Patient Care and Clinical Practice: This review addresses specific clinical controversies that drive vasopressin use in septic shock patients in real-world practice. Conclusion: Vasopressin should remain second-line adjunct to norepinephrine to augment mean arterial pressures. Dosing should be initiated at 0.03 U/min, and higher doses offer minimal benefit. There are conflicting data on the impact of weight on vasopressin response. Studies have failed to show renal benefit with vasopressin use or an interaction with corticosteroid therapy.

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.