Discontinuation of vasopressin before norepinephrine increases the incidence of hypotension in patients recovering from septic shock: a retrospective cohort study

How We Escalate Vasopressor and Corticosteroid Therapy in Patients With Septic Shock

Septic shock is defined by the need for vasopressor agents to correct hypotension and lactic acidosis resulting from infection, with 30%-40% case fatality rates. The care of patients with worsening septic shock involves multiple treatment decisions involving vasopressor choices and adjunctive treatments. In this edition of "How I Do It", we provide a case-based discussion of common clinical decisions regarding choice of first-line vasopressor, BP targets, route of vasopressor delivery, use of secondary vasopressors, and adjunctive medications. We also consider diagnostic approaches, treatment, and monitoring strategies for the patient with worsening shock, as well as approaches to difficult weaning of vasopressors.

Management of Hemorrhagic Shock: Physiology Approach, Timing and Strategies

Hemorrhagic shock (HS) management is based on a timely, rapid, definitive source control of bleeding/s and on blood loss replacement. Stopping the hemorrhage from progressing from any named and visible vessel is the main stem fundamental praxis of efficacy and effectiveness and an essential, obligatory, life-saving step. Blood loss replacement serves the purpose of preventing ischemia/reperfusion toxemia and optimizing tissue oxygenation and microcirculation dynamics. The "physiological classification of HS" dictates the timely management and suits the 'titrated hypotensive resuscitation' tactics and the 'damage control surgery' strategy. In any hypotensive but not yet critical shock, the body's response to a fluid load test determines the cut-off point between compensation and progression between the time for adopting conservative treatment and preparing for surgery or rushing to the theater for rapid bleeding source control. Up to 20% of the total blood volume is given to refill the unstressed venous return volume. In any critical level of shock where, ab initio, the patient manifests signs indicating critical physiology and impending cardiac arrest or cardiovascular accident, the balance between the life-saving reflexes stretched to the maximum and the insufficient distal perfusion (blood, oxygen, and substrates) remains in a liable and delicate equilibrium, susceptible to any minimal change or interfering variable. In a cardiac arrest by exsanguination, the core of the physiological issue remains the rapid restoration of a sufficient venous return, allowing the heart to pump it back into systemic circulation either by open massage via sternotomy or anterolateral thoracotomy or spontaneously after aorta clamping in the chest or in the abdomen at the epigastrium under extracorporeal resuscitation and induced hypothermia. This is the only way to prevent ischemic damage to the brain and the heart. This is accomplishable rapidly and efficiently only by a direct approach, which is a crush laparotomy if the bleeding is coming from an abdominal +/- lower limb site or rapid sternotomy/anterolateral thoracotomy if the bleeding is coming from a chest +/- upper limbs site. Without first stopping the bleeding and refilling the heart, any further exercise is doomed to failure. Direct source control via laparotomy/thoracotomy, with the concomitant or soon following venous refilling, are the two essential, initial life-saving steps.

Vasopressor Discontinuation Order in Septic Shock With Reduced Left Ventricular Function

BACKGROUND

The optimal vasopressor management for septic patients with left ventricular (LV) dysfunction has not been well established, and current evidence is conflicting regarding the optimal vasopressor discontinuation order.

OBJECTIVE

The objective was to evaluate the impact of LV dysfunction on the hemodynamic management of septic shock by assessing the incidence of clinically significant hypotension after vasopressor discontinuation.

METHODS

In this single-center, retrospective cohort study, adult patients were included if they met the Sepsis-3 definition of septic shock, had LV dysfunction (defined as an ejection fraction ≤40%), and received norepinephrine and vasopressin as the last vasopressors discontinued. The primary outcome was the incidence of clinically significant hypotension following discontinuation of vasopressin or norepinephrine. Clinically significant hypotension was defined as a MAP less than 60 mmHg and the need for either: 1) the reinstitution of the previously discontinued agent at any dosage, 2) the receipt of at least 500 mL of a crystalloid at a rate of at least 500 mL/hour, 3) or the receipt of at least 25 grams of albumin 5% at a rate of at least 25 gram/hour. Secondary outcomes included intensive care unit (ICU) and hospital lengths of stay, and ICU and hospital mortality.

RESULTS

A total of 78 patients met inclusion criteria, with 37 patients having vasopressin discontinued first and 41 having norepinephrine discontinued first. Clinically significant hypotension occurred in 28 patients (76%) following the discontinuation of vasopressin, compared to 28 patients (81%) following the discontinuation of norepinephrine (p = 0.61). ICU length of stay was 9 days in the vasopressin discontinued first cohort, compared to 15 days in the norepinephrine discontinued first cohort (p = 0.01). There was no statistically significant difference in mortality observed.

CONCLUSION

The discontinuation order of norepinephrine and vasopressin did not impact the incidence of clinically significant hypotension in patients with septic shock and LV dysfunction, but may influence ICU length of stay, although other factors may have impacted this finding.

Incidence of Hypotension Associated With Two Different Vasopressin Discontinuation Strategies in the Recovery Phase of Septic Shock

INTRODUCTION

Safe and effective vasopressor withdrawal strategies during the recovery phase of septic shock lack consensus and are not addressed in clinical practice guidelines. The purpose of this study was to compare the incidence of clinically relevant hypotension associated with different vasopressin (AVP) discontinuation strategies.

METHODS

This was a single-center, retrospective, cohort study, conducted at a university medical center over a three-year period. Adult patients ≥18 years with septic shock were included in the study. Patients were stratified into two groups; patients incrementally weaned from AVP and patients in which AVP was abruptly discontinued. The primary endpoint was to compare the incidence of clinically relevant hypotension between study groups up to 24 hours following discontinuation. Secondary analyses included the incidence of any hypotensive event up to 24 hours after AVP cessation, intensive care unit and hospital length of stay, and in-hospital mortality.

RESULTS

A total of 74 patients (n = 46 AVP wean and n = 28 AVP no-wean) met inclusion criteria and were included in the study. The primary outcome was not statistically different between groups. Clinically relevant hypotension occurred in 24 patients (52.3%) and 16 patients (57.1%) in the AVP wean and AVP no-wean groups, respectively (P = .68). There were no significant differences in any secondary clinical outcome between the two study groups.

CONCLUSION

No differences were found in the incidence of clinically relevant hypotension, length of stay, or mortality between AVP weaning and no-weaning discontinuation strategies. These findings suggest incremental weaning and abrupt withdrawal of AVP are both acceptable discontinuation strategies.

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.

Analysis of Vasopressor Discontinuation and the Incidence of Rebound Hypotension in Patients With Septic Shock

Purpose: The purpose of this study was to examine the incidence of rebound hypotension in patients with septic shock requiring both norepinephrine and vasopressin infusions once discontinuation of 1 of these agents is warranted. Methods: A multicenter, retrospective study was conducted in 3 hospitals within a single health system between January 1, 2016, and December 31, 2017. The study population included adults, 18 years and older, diagnosed with septic shock and requiring concurrent infusions of norepinephrine and vasopressin. The primary outcome evaluated the incidence of rebound hypotension within 24 hours after the first vasopressor was discontinued. Secondary outcomes included intensive care unit length of stay, hospital length of stay, total vasopressor duration, and the time to rebound hypotension after first vasopressor discontinuation. Results: A total of 69 patients were included in the study, 38 in the vasopressin discontinued first group and 31 in the norepinephrine discontinued first group. Rebound hypotension occurred in 82% of patients in the vasopressin discontinued first group compared with 48% in the norepinephrine discontinued first group ( P = .004). No differences were observed in secondary outcomes, including intensive care unit or hospital length of stay, total vasopressor duration, or the time to rebound hypotension. Conclusions: Discontinuation of norepinephrine before vasopressin may lead to less incidence of rebound hypotension in patients with septic shock who require concurrent norepinephrine and vasopressin infusions. Similar to previous studies, this study found no difference in secondary outcomes.

Impact of the Sequence of Norepinephrine and Vasopressin Discontinuation in Patients Recovering From Septic Shock

Background: Septic shock is a serious medical condition affecting millions of people each year and guidelines direct vasopressor use in these patients. However, there is little information as to which vasopressor should be discontinued first. Objective: The objective of this study was to assess the impact of the sequence of norepinephrine and vasopressin discontinuation on intensive care unit (ICU) length of stay. Methods: This was a single-center retrospective cohort study conducted at The University of Tennessee Medical Center in Knoxville, Tennessee. Patients included in this study were adults 18 years of age and older with a diagnosis of septic shock who received norepinephrine in combination with vasopressin. Patients were excluded if norepinephrine or vasopressin were not the last 2 vasoactive agents used or if the patient expired or care was withdrawn. Measurements and Main Results: A total of 86 patients were included in this study, with 34 patients in the norepinephrine discontinued first group (NDF) and 52 in the vasopressin discontinued first group (VDF). For the primary outcome of ICU length of stay, no statistically significant difference was found between the NDF and the VDF groups (9.38 days vs 11.07 days, P = .313). The secondary outcome of the dose of norepinephrine at which vasopressin was initiated was also found to not be significant between the NDF and VDF groups (22 µg/min vs 31.1 µg/min, P = .11). The rates of hypotension within 24 hours of discontinuation of the first agent were also not significant between the NDF and VDF groups (17% vs 31%, P = .38). Conclusions: Based on the results of this study, there was significant no difference in ICU length of stay based on the sequence of discontinuation between norepinephrine and vasopressin in patients recovering from septic shock.

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.

Incidence of Hypotension after Discontinuation of Norepinephrine or Arginine Vasopressin in Patients with Septic Shock: a Systematic Review and Meta-Analysis

BACKGROUND

There has been no consensus regarding the discontinuation order of vasopressors in patients recovering from septic shock treated with concomitant norepinephrine (NE) and arginine vasopressin (AVP). The aim of this study was to compare the incidence of hypotension within 24 hours based on whether NE or AVP was discontinued first in order to determine the optimal sequence for discontinuation of vasopressors.

METHODS

A systematic literature search was conducted in MEDLINE, Embase, and the Cochrane Central Register. The primary end-point was incidence of hypotension within 24 hours after discontinuation of the first vasopressor.

RESULTS

We identified five studies comprising 930 patients, of whom 631 (67.8%) discontinued NE first and 299 (32.2%) discontinued AVP first. In pooled estimates, a random-effect model showed that discontinuation of NE first was associated with a significant reduction of the incidence of hypotension compared to discontinuing AVP first (31.8% vs. 54.8%; risk ratios, 0.35; 95% confidence interval, 0.16 to 0.76; P = 0.008; I² = 90.7%). Although a substantial degree of heterogeneity existed among the trials, we could not identify the significant source of bias. In addition, there were no significant differences in intensive care unit (ICU) mortality, in-hospital mortality, 28-day mortality, or ICU length of stay between the groups.

CONCLUSION

Discontinuing NE prior to AVP was associated with a lower incidence of hypotension in patients recovering from septic shock. However, our results should be interpreted with caution, due to the considerable between-study heterogeneity.

Mortality, Morbidity, and Costs After Implementation of a Vasopressin Guideline in Medical Intensive Care Patients With Septic Shock: An Interrupted Time Series Analysis

Background: Vasopressin decreases vasopressor requirements in patients with septic shock. However, the optimal norepinephrine dose for initiation or cessation of vasopressin is unclear. Objective: Analyze monthly intensive care unit (ICU) mortality rates 1 year preimplementation and postimplementation of a guideline suggesting a norepinephrine dose of 50 µg/min or more for initiation of vasopressin and early cessation of vasopressin. Methods: This retrospective quasi-experimental study included adult patients with septic shock admitted to the medical ICU of a tertiary care medical center over 2 years. Time periods were evaluated with interrupted time series analysis. Results: A total of 1148 patients were included: 573 patients preguideline and 575 patients postguideline. Group characteristics were well balanced at baseline, except patients postguideline had higher sequential organ failure assessment scores. Postguideline, fewer patients were initiated on vasopressin (305 [53.2%] vs 217 [37.7%], absolute difference -15.5% [95% CI -21.2% to -9.8%]), and the norepinephrine dose at vasopressin initiation was higher (median 25 [interquartile range 18, 40] µg/min vs 40 [22, 52] µg/min; median difference 15 [95% CI 11 to 19] µg/min; P < 0.01). After guideline implementation, there was no evidence for a difference in ICU mortality rate slope (slope change 0.07% [95% CI -0.8% to 1.0%] per month; P 0.87), but the vasoactive cost level decreased by US$183 (95% CI -US$327 to -US$39) per patient immediately after implementation. Conclusion and Relevance: Implementation of a guideline suggesting a high norepinephrine dose threshold for vasopressin initiation and early vasopressin cessation in patients with septic shock appears to be safe and may decrease vasoactive costs.

Prescribing of Pressor Agents in Septic Shock: A Survey of Critical Care Pharmacists

Background: Pressor agents are recognized as high-alert medications by the Institute for Safe Medication Practices, but little evidence is available to guide their use in septic shock. Objective: Characterize the use of pressor agents for septic shock in clinical practice. Methods: A cross-sectional electronic survey assessing demographics, institutional practices, and respondent perceptions related to pressor agents was distributed to the American College of Clinical Pharmacy Critical Care Practice and Research Network. The primary outcome was the use of a weight-based dosing (WBD) strategy versus non-WBD strategy for norepinephrine. Descriptive statistics were used to summarize survey results. Binary logistic regression was performed to determine variables associated with dosing strategies. Results: The survey was completed by 223 respondents. The typical respondent worked in a medical or mixed intensive care unit at a teaching hospital and had training and/or board certification beyond the Doctor of Pharmacy degree. Nearly all respondents (n = 221, 99%) reported norepinephrine as the first-line vasopressor for septic shock; however, 38% used WBD and 60% used non-WBD. In logistic regression, respondents located in the South and practicing at institutions with larger numbers of intensive care unit beds were more likely to use WBD for norepinephrine infusions. Similar findings were observed with epinephrine and phenylephrine. Conclusion: Wide variability exists in prescribing patterns of pressor agents and in pharmacist perceptions regarding best practices. The use of WBD varied based on institutional characteristics and resulted in higher maximum allowable infusion rates of pressor agents. Future research should compare dosing strategies to identify associations with patient outcomes.

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

Background

Clinician preferences and practices regarding appropriate vasopressin use in light of its increased acquisition cost secondary to rebranding has not been evaluated or described since the most recent iteration of the Surviving Sepsis Campaign Guideline was published.

Objective

To assess vasopressin cost containment initiatives and pharmacists' opinions regarding appropriate vasopressin use.

Methods

A scenario-based survey was distributed to critical care and emergency medicine pharmacists. Responses were characterized using frequency and descriptive statistics. Categorical variables between those who implemented changes (Vasopressin Cost Consideration) and those who did not (Usual Care) were compared using chi-square or Fisher's exact tests. McNemar's test was used to compare responses in clinical scenarios between Vasopressin Cost Consideration and Usual Care groups.

Results

Among 1757 pharmacists surveyed, 200 (11.3%) responded. When respondents considered vasopressin cost and evidence (vs evidence alone), fewer respondents would use vasopressin adjunctively with norepinephrine (21% vs 26.6%, P = 0.031), to raise mean arterial pressure compared with epinephrine (65.2% vs 72.3%, P = 0.012), or to reduce norepinephrine infusion rates (71.4% vs 81.4%, P < 0.001), but would use with steroids (62.4% vs 28.3%, P < 0.001). Most (72%) respondents had implemented vasopressin cost containment and/or education initiatives. The Vasopressin Cost Consideration group respondents were more likely to initiate vasopressin at 0.03 units/minute without titrating (47.9% vs 33.9%, P = 0.045).

Conclusion

Since vasopressin was generically rebranded, most institutions have implemented at least one initiative to reduce vasopressin use and/or educate clinicians about its appropriate use. When vasopressin acquisition costs were considered, pharmacists recommended its use less frequently, particularly in clinical scenarios where its use is controversial.

Vasoactive Agents for Adult Septic Shock: An Update and Review

PURPOSE

The objective of this article is to discuss the pharmacology, side effects, and clinical application of vasoactive therapy in the management of adult septic shock.

SUMMARY

Sepsis is one of the most common reasons for admission to an intensive care unit with the incidence estimated to be greater than 750 000 cases per year in the United States. Clinicians should understand the basic pharmacology of available vasoactive agents to allow for routine and complex management of septic shock.

CONCLUSION

While advances in research, identification, and early implementation of best practices for the treatment of sepsis has reduced mortality, rates remain high. Vasopressors and inotropes remain part of the core therapeutic modalities of sepsis management. Norepinephrine is the first-line vasopressor of choice for septic shock, though secondary vasopressors can be used depending on the patient's circumstances.

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.

Incidence of hypotension according to the discontinuation order of vasopressors in the management of septic shock: a prospective randomized trial (DOVSS)

BACKGROUND

Vasopressin (AVP) is commonly added to norepinephrine (NE) to reverse shock in patients with sepsis. However, there are no data to support the appropriate strategy of vasopressor tapering in patients on concomitant NE and AVP who are recovering from septic shock. Therefore, the objective of this study was to evaluate the incidence of hypotension while tapering vasopressors in patients on concomitant NE and AVP recovering from septic shock.

METHODS

Patients with septic shock receiving concomitant NE and AVP were randomly assigned to taper NE first (NE group) or AVP first (AVP group). The primary end point was the incidence of hypotension within one hour of tapering of the first vasopressor. We also evaluated the association between serum copeptin levels and the occurrence of hypotension.

RESULTS

The study was stopped early due to a significant difference in the incidence of hypotension after 38 and 40 patients were enrolled in the NE group and the AVP group, respectively. There were 26 patients (68.4%) in the NE group versus 9 patients (22.5%) in the AVP group who developed hypotension after tapering the first vasopressor (p < 0.001). There was a similar finding during the subsequent tapering of the second vasopressor (64.5% in the NE vs 25.0% in the AVP group, p = 0.020). Finally, NE tapering was significantly associated with hypotension during the study period (hazard ratio, 2.221; 95% confidence interval, 1.106-4.460; p = 0.025). The serum copeptin level was lower in patients in whom hypotension developed during tapering of AVP than it was in those without hypotension.

CONCLUSIONS

Tapering NE rather than AVP may be associated with a higher incidence of hypotension in patients recovering from septic shock who are on concomitant NE and AVP. However, further studies with larger sample sizes are required to better determine the appropriate strategy for vasopressor tapering.

TRIAL REGISTRATION

ClinicalTrials.gov, NCT01493102 . Registered on 15 December 2011.

Evaluating Vasopressor Discontinuation Strategies in Patients With Septic Shock on Concomitant Norepinephrine and Vasopressin Infusions

BACKGROUND

There is little data guiding clinicians on how to discontinue vasopressors among septic shock patients on concomitant norepinephrine (NE) and vasopressin (VP).

OBJECTIVE

To determine the incidence of hypotension within 24 hours of discontinuing NE (NE DC first) versus VP (VP DC first) first in septic shock patients.

METHODS

This retrospective study evaluated septic shock patients admitted to the medical intensive care unit (MICU) and surgical ICU (SICU) receiving concomitant NE and VP. Receipt of additional vasopressors, mixed shock states, expired or care withdrawn, and NE and VP discontinued simultaneously were exclusion criteria. The primary outcome was incidence of hypotension within 24 hours of first vasopressor discontinuation. Secondary outcomes included time to hypotension, hospital length of stay (LOS), ICU LOS, and ICU mortality.

RESULTS

A total of 80 patients were included (NE DC first [n = 35]; VP DC first [n = 45]), with a median age of 73 years and median modified Acute Physiology and Chronic Health Evaluation II and Sequential Organ Failure Assessment scores of 21 and 7, respectively. More patients in the NE DC first group were in the SICU (42.9% vs 20.0%; P = 0.048) with more intra-abdominal infections (40.0% vs 15.6%; P = 0.021) and fewer appropriate empirical antibiotics (62.9% vs 86.7%; P = 0.018). Hypotension within 24 hours of first agent discontinuation was higher in the VP DC first group (28.6% vs 62.2%; P = 0.004), with similar hospital LOS and ICU mortality. Multivariate analysis identified VP DC first as an independent predictor of hypotension (odds ratio = 7.2; CI = 2.3-22.7).

CONCLUSION

Among septic shock patients on concomitant NE and VP, discontinuation of VP first was associated with an increased incidence of hypotension; future prospective control trials are warranted.

Hemodynamic Instability Secondary to Vasopressin Withdrawal in Septic Shock

RATIONALE

Vasopressors such as norepinephrine are first line for support of mean arterial pressure (MAP) in the management of septic shock. Their use, however, is commonly associated with many adverse events. These detriments frequently trigger the use of alternative, noncatecholamine therapies, including vasopressin. Vasopressin deficiency is a known physiologic consequence of septic shock, and while guidelines recommend vasopressin in addition to norepinephrine, no consensus exists on the duration of deficiency or ideal time of cessation. Studies have suggested that vasopressin discontinuation prior to other vasopressors may lead to hypotension; however, data are limited. This study evaluates the optimal sequence for the discontinuation of vasopressin therapy in septic shock.

METHODS

This was a 1-year retrospective study of 152 patients admitted to the medical intensive care unit (ICU) with septic shock who received concurrent norepinephrine and vasopressin for vasoactive support. Patients were excluded if death occurred on vasopressors, within 24 hours after discontinuation of vasopressors, or within 48 hours of ICU admission. The primary outcome of hemodynamic instability included incidence of hypotension after vasopressor discontinuation (2 consecutive MAPs < 60 mm Hg), fluid bolus administration, greater than 0.05 μg/kg/min increase in norepinephrine requirements, or addition of an alternative vasopressor. Secondary outcomes included time to hypotension, total vasopressor duration, arrhythmias, mortality, and length of stay.

RESULTS

Ninety-one patients met exclusion criteria, resulting in 61 patients for evaluation. Vasopressin was the first vasoactive therapy to be discontinued in 19 patients and last in 42 patients. Baseline characteristics and the use of potentially confounding treatments known to effect MAP were similar between groups. Discontinuation of vasopressin first was associated with a significant increase in hemodynamic instability (74% vs 16.7%, P < .01), with a shorter time to hemodynamic instability (5 vs 15 hours, P < .01). Secondary outcomes were similar.

CONCLUSION

Vasopressin discontinuation prior to cessation of norepinephrine infusion was associated with an increased risk of hemodynamic instability.

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.

Hemorrhagic shock: The "physiology approach"

A shift of approach from ‘clinics trying to fit physiology’ to the one of ‘physiology to clinics’, with interpretation of the clinical phenomena from their physiological bases to the tip of the clinical iceberg, and a management exclusively based on modulation of physiology, is finally surging as the safest and most efficacious philosophy in hemorrhagic shock. ATLS^® classification and recommendations on hemorrhagic shock are not helpful because antiphysiological and potentially misleading. Hemorrhagic shock needs to be reclassified in the direction of usefulness and timing of intervention: in particular its assessment and management need to be tailored to physiology.

Bench-to-bedside review: Vasopressin in the management of septic shock

This review of vasopressin in septic shock differs from previous reviews by providing more information on the physiology and pathophysiology of vasopressin and vasopressin receptors, particularly because of recent interest in more specific AVPR1a agonists and new information from the Vasopressin and Septic Shock Trial (VASST), a randomized trial of vasopressin versus norepinephrine in septic shock. Relevant literature regarding vasopressin and other AVPR1a agonists was reviewed and synthesized. Vasopressin, a key stress hormone in response to hypotension, stimulates a family of receptors: AVPR1a, AVPR1b, AVPR2, oxytocin receptors and purinergic receptors. Rationales for use of vasopressin in septic shock are as follows: first, a deficiency of vasopressin in septic shock; second, low-dose vasopressin infusion improves blood pressure, decreases requirements for norepinephrine and improves renal function; and third, a recent randomized, controlled, concealed trial of vasopressin versus norepinephrine (VASST) suggests low-dose vasopressin may decrease mortality of less severe septic shock. Previous clinical studies of vasopressin in septic shock were small or not controlled. There was no difference in 28-day mortality between vasopressin-treated versus norepinephrine-treated patients (35% versus 39%, respectively) in VASST. There was potential benefit in the prospectively defined stratum of patients with less severe septic shock (5 to 14 μg/minute norepinephrine at randomization): vasopressin may have lowered mortality compared with norepinephrine (26% versus 36%, respectively, P = 0.04 within stratum). The result was robust: vasopressin also decreased mortality (compared with norepinephrine) if less severe septic shock was defined by the lowest quartile of arterial lactate or by use of one (versus more than one) vasopressor at baseline. Other investigators found greater hemodynamic effects of higher dose of vasopressin (0.06 units/minute) but also unique adverse effects (elevated liver enzymes and serum bilirubin). Use of higher dose vasopressin requires further evaluation of efficacy and safety. There are very few studies of interactions of therapies in critical care - or septic shock - and effects on mortality. Therefore, the interaction of vasopressin infusion, corticosteroid treatment and mortality of septic shock was evaluated in VASST. Low-dose vasopressin infusion plus corticosteroids significantly decreased 28-day mortality compared with corticosteroids plus norepinephrine (44% versus 35%, respectively, P = 0.03; P = 0.008 interaction statistic). Prospective randomized controlled trials would be necessary to confirm this interesting interaction. In conclusion, low-dose vasopressin may be effective in patients who have less severe septic shock already receiving norepinephrine (such as patients with modest norepinephrine infusion (5 to 15 μg/minute) or low serum lactate levels). The interaction of vasopressin infusion and corticosteroid treatment in septic shock requires further study.