Survival after shock requiring high-dose vasopressor therapy

Severe Early Graft Dysfunction Post-Heart Transplantation: Two Clinical Trajectories and Diastolic Perfusion Pressure as a Predictor of Mechanical Circulatory Support

BACKGROUND

Severe early graft dysfunction (EGD) is defined by mechanical circulatory support (MCS) <24 hours of heart transplantation (HT). We classified severe EGD based on timing of post-HT MCS: 'Immediate' intra-operative vs 'Delayed' post-operative MCS (after admission into intensive care unit (ICU) from operating theatre). We hypothesised that (i) risk factors and clinical course differ between 'Immediate' and 'Delayed' MCS; and (ii) diastolic perfusion pressure (DPP=diastolic blood pressure-central venous pressure) and Norepinephrine equivalents (NE=sum of vasopressor doses), as measures of vasoplegia are related to 'Delayed' MCS.

METHODS

Two-centre study of 216 consecutive patients who underwent HT. Recipient, donor, vasopressor doses and hemodynamic data at T0 and T6 (on admission and 6 hours after admission into ICU) were collected.

RESULTS

Of the 216 patients, 67 patients had severe EGD ('Immediate' MCS: n=43, 'Delayed' MCS: n=24). The likelihood of 'immediate' MCS but not 'delayed' MCS increased with increasing warm ischemic and cardiopulmonary bypass times on multinomial regression analysis with 'no MCS' as the referent group. One-year mortality was highest in 'Immediate' MCS vs 'no MCS' and 'delayed' MCS (34.9% vs 3.4% and 8% respectively, P<0.001). Of the patients who had no immediate post-transplant MCS, DPP and NE at T6 were independently associated with subsequent 'delayed' MCS'. Sensitivity and specificity of NE ≥0.2mcg/kg/min for 'Delayed' MCS were 71% and 81%. Sensitivity and specificity of DPP of ≥40mmHg for No MCS were 83% and 74%. The discriminatory value of systemic vascular resistance for 'Delayed' MCS was poor.

CONCLUSION

Risk factors and one-year survival differed significantly between 'Immediate' and 'Delayed' post-HT MCS. The latter is related to lower DPP and higher NE, which is consistent with vasoplegia as the dominant pathophysiology.

Renin Levels and Angiotensin II Responsiveness in Vasopressor-Dependent Hypotension

OBJECTIVES

The relationship between renin levels, exposure to renin-angiotensin system (RAS) inhibitors, angiotensin II (ANGII) responsiveness, and outcome in patients with vasopressor-dependent vasodilatory hypotension is unknown.

DESIGN

We conducted a single-center prospective observational study to explore whether recent RAS inhibitor exposure affected baseline renin levels, whether baseline renin levels predicted ANGII responsiveness, and whether renin levels at 24 hours were associated with clinical outcomes.

SETTING

An academic ICU in Melbourne, VIC, Australia.

PATIENTS

Forty critically ill adults who received ANGII as the primary agent for vasopressor-dependent vasodilatory hypotension who were included in the Acute Renal effects of Angiotensin II Management in Shock study.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

After multivariable adjustment, recent exposure to a RAS inhibitor was independently associated with a relative increase in baseline renin levels by 198% (95% CI, 36-552%). The peak amount of ANGII required to achieve target mean arterial pressure was independently associated with baseline renin level (increase by 46% per ten-fold increase; 95% CI, 8-98%). Higher renin levels at 24 hours after ANGII initiation were independently associated with fewer days alive and free of continuous renal replacement therapy (CRRT) (-7 d per ten-fold increase; 95% CI, -12 to -1).

CONCLUSIONS

In patients with vasopressor-dependent vasodilatory hypotension, recent RAS inhibitor exposure was associated with higher baseline renin levels. Such higher renin levels were then associated with decreased ANGII responsiveness. Higher renin levels at 24 hours despite ANGII infusion were associated with fewer days alive and CRRT-free. These preliminary findings emphasize the importance of the RAS and the role of renin as a biomarker in patients with vasopressor-dependent vasodilatory hypotension.

Position Paper on the Reporting of Norepinephrine Formulations in Critical Care from the Society of Critical Care Medicine and European Society of Intensive Care Medicine Joint Task Force

OBJECTIVES

To provide guidance on the reporting of norepinephrine formulation labeling, reporting in publications, and use in clinical practice.

DESIGN

Review and task force position statements with necessary guidance.

SETTING

A series of group conference calls were conducted from August 2023 to October 2023, along with a review of the available evidence and scope of the problem.

SUBJECTS

A task force of multinational and multidisciplinary critical care experts assembled by the Society of Critical Care Medicine and the European Society of Intensive Care Medicine.

INTERVENTIONS

The implications of a variation in norepinephrine labeled as conjugated salt (i.e., bitartrate or tartrate) or base drug in terms of effective concentration of norepinephrine were examined, and guidance was provided.

MEASUREMENTS AND MAIN RESULTS

There were significant implications for clinical care, dose calculations for enrollment in clinical trials, and results of datasets reporting maximal norepinephrine equivalents. These differences were especially important in the setting of collaborative efforts across countries with reported differences.

CONCLUSIONS

A joint task force position statement was created outlining the scope of norepinephrine-dose formulation variations, and implications for research, patient safety, and clinical care. The task force advocated for a uniform norepinephrine-base formulation for global use, and offered advice aimed at appropriate stakeholders.

Angiotensin ii therapy in refractory septic shock: which patient can benefit most? A narrative review

Patients with septic shock who experience refractory hypotension despite adequate fluid resuscitation and high-dose noradrenaline have high mortality rates. To improve outcomes, evidence-based guidelines recommend starting a second vasopressor, such as vasopressin, if noradrenaline doses exceed 0.5 µg/kg/min. Recently, promising results have been observed in treating refractory hypotension with angiotensin II, which has been shown to increase mean arterial pressure and has been associated with improved outcomes. This narrative review aims to provide an overview of the pathophysiology of the renin-angiotensin system and the role of endogenous angiotensin II in vasodilatory shock with a focus on how angiotensin II treatment impacts clinical outcomes and on identifying the population that may benefit most from its use.

Exploring the norepinephrine to angiotensin II conversion ratio in patients with vasodilatory hypotension: A post-hoc analysis of the ARAMIS trial

PURPOSE

Angiotensin II is approved for catecholamine-refractory vasodilatory shock but the conversion dose ratio from norepinephrine to angiotensin II remains unclear.

METHODS

We conducted a post-hoc analysis of the Acute Renal effects of Angiotensin II Management in Shock (ARAMIS) trial involving patients with vasodilatory hypotension. We determined the norepinephrine equivalent dose immediately prior to angiotensin II initiation and calculated the conversion dose ratio between norepinephrine and angiotensin II. We performed subgroup analyses based on recent exposure to angiotensin receptor blockers (ARBs) and renin levels at baseline.

RESULTS

In 37 patients, the median conversion dose ratio between norepinephrine equivalent and angiotensin II was to 10:1 for norepinephrine bitartrate (5:1 for norepinephrine base). The conversion ratio was not affected by the baseline renin, with a median ratio of 10 (7-21) in the high renin group versus 12 (5-22) in the low renin group. Finally, exposure to ARBs prior admission appeared to diminish the conversion ratio with a median ratio of 7 (4-13) in ARB patients vs. 12 (7-22) in non-ARB patients.

CONCLUSIONS

The norepinephrine to angiotensin II conversion dose ratio is 10:1 in a vasodilatory hypotension population. These findings can guide clinicians and researchers in the use, dosing, and study of angiotensin II in critical care.

Value function assessment to different RL algorithms for heparin treatment policy of patients with sepsis in ICU

Heparin is a critical aspect of managing sepsis after abdominal surgery, which can improve microcirculation, protect organ function, and reduce mortality. However, there is no clinical evidence to support decision-making for heparin dosage. This paper proposes a model called SOFA-MDP, which utilizes SOFA scores as states of MDP, to investigate clinic policies. Different algorithms provide different value functions, making it challenging to determine which value function is more reliable. Due to ethical restrictions, we cannot test all policies on patients. To address this issue, we proposed two value function assessment methods: action similarity rate and relative gain. We experimented with heparin treatment policies for sepsis patients after abdominal surgery using MIMIC-IV. In the experiments, TD(0) shows the most reliable performance. Using the action similarity rate and relative gain to assess AI policy from TD(0), the agreement rates between AI policy and "good" physician's actual treatment are 64.6% and 73.2%, while the agreement rates between AI policy and "bad" physician's actual treatment are 44.1% and 35.8%, the gaps are 20.5% and 37.4%, respectively. External validation using action similarity rate and relative gain based on eICU resulted in agreement rates of 61.5% and 69.1% with the "good" physician's treatment, and 45.2% and 38.3% with the "bad" physician's treatment, with gaps of 16.3% and 30.8%, respectively. In conclusion, the model provides instructive support for clinical decisions, and the evaluation methods accurately distinguish reliable and unreasonable outcomes.

Long-Term Retention of Advanced Cardiovascular Life Support Knowledge and Confidence in Doctor of Pharmacy Students

OBJECTIVE

This study aimed to evaluate the impact of American Heart Association (AHA) advanced cardiovascular life support (ACLS) education and training on long-term retention of ACLS knowledge and confidence in Doctor of Pharmacy (PharmD) students.

METHODS

This multicenter study included PharmD students who received ACLS training through different means: 1-hour didactic lecture (didactic), 1-hour didactic lecture with 2-hour skills practice (didactic + skills), and comprehensive AHA ACLS certification through an elective course (elective-certification). Students completed a survey before training, immediately after training, and at least 6-12 months after training to assess demographics and ACLS confidence and knowledge. The primary outcome was a passing score, defined as ≥ 84% on the long-term knowledge assessment. Secondary outcomes included overall knowledge score and perceived confidence, assessed using the Dreyfus model.

RESULTS

The long-term assessment was completed by 160 students in the didactic group, 66 in the didactic + skills group, and 62 in the elective-certification group. Six (4%), 8 (12%), and 14 (23%) received a passing score on the long-term knowledge assessment in the didactic, didactic + skills, and elective-certification groups, respectively. The median (IQR) scores on the long-term knowledge assessment were 50% (40-60), 60% (50-70), and 65% (40-80) in the 3 groups. On the long-term assessment, confidence was higher in the elective-certification group, demonstrated by more self-ratings of competent, proficient, and expert, and fewer self-ratings of novice and advanced beginner.

CONCLUSION

Long-term retention of ACLS knowledge was low in all groups, but was higher in students who received AHA ACLS certification through an ACLS elective course.

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.

Trajectory of PaO2/FiO2 Ratio in Shock After Angiotensin II

INTRODUCTION

High-dose catecholamines can impair hypoxic pulmonary vasoconstriction and increase shunt fraction. We aimed to determine if Angiotensin II (Ang-2) is associated with improved PaO2/FiO2 and SpO2/FiO2 in patients in shock.

METHODS

Adult patients at four tertiary care centers and one community hospital in the United States who received Ang-2 from July 2018-September 2020 were included in this retrospective, observational cohort study. PaO2, SpO2, and FiO2 were measured at 13 timepoints during the 48-h before and after Ang-2 initiation. Piecewise linear mixed models of PaO2/FiO2 and SpO2/FiO2 were created to evaluate hourly changes in oxygenation after Ang-2 initiation. The difference in the proportion of patients with PaO2/FiO2 ≤ 300 mm Hg at the time of Ang-2 initiation and 48 h after was also examined.

RESULTS

The study included 254 patients. In the 48 h prior to Ang-2 initiation, oxygenation was significantly declining (hourly PaO2/FiO2 change -4.7 mm Hg/hr, 95% CI - 6.0 to -3.5, p < .001; hourly SpO2/FiO2 change -3.1/hr, 95% CI-3.7 to -2.4, p < .001). Ang-2 treatment was associated with significant improvements in PaO2/FiO2 and SpO2/FiO2 in the 48-h after initiation (hourly PaO2/FiO2 change +1.5 mm Hg/hr, 95% CI 0.5-2.5, p  =  .003; hourly SpO2/FiO2 change +0.9/hr, 95% CI 0.5-1.2, p < .001). The difference in the hourly change in oxygenation before and after Ang-2 initiation was also significant (pinteraction < 0.001 for both PaO2/FiO2 and SpO2/FiO2). This improvement was associated with significantly fewer patients having a PaO2/FiO2 ≤ 300 mm Hg at 48 h compared to baseline (mean difference -14.9%, 95% CI -25.3% to -4.6%, p  =  .011). Subgroup analysis found that patients with either a baseline PaO2/FiO2 ≤ 300 mm Hg or a norepinephrine-equivalent dose requirement >0.2 µg/kg/min had the greatest associations with oxygenation improvement.

CONCLUSIONS

Ang-2 is associated with improved PaO2/FiO2 and SpO2/FiO2. The mechanisms for this improvement are not entirely clear but may be due to catecholamine-sparing effect or may also be related to improved ventilation-perfusion matching, intrapulmonary shunt, or oxygen delivery.

Prophylactic Administration with Methylene Blue Improves Hemodynamic Stabilization During Obstructive Jaundice-Related Diseases' Operation: a Blinded Randomized Controlled Trial

OBJECTIVES

Patients with obstruction jaundice are at a high risk of hypotension and need high volume of fluids and a high dose of catecholamine to maintain organ perfusion during operation procedure. All these likely contribute to high perioperative morbidity and mortality. The aim of the study is to evaluate the effects of methylene blue on the hemodynamics in patients undergoing surgeries associated with obstructive jaundice.

DESIGN

A prospective, randomized, and controlled clinical study.

SETTING

The enrolled patients randomly received 2 mg/kg of methylene blue in saline or saline (50 ml) before anesthesia induction. The primary outcome was the frequency and dose of noradrenaline administration to maintain mean arterial blood pressure over 65 mmHg or > 80% of baseline, and systemic vascular resistance (SVR) over 800 dyne/s/cm5 during operation. The secondary outcomes were liver and kidney functions, and ICU stay.

PATIENTS

Seventy patients were enrolled in the study and randomly assigned to receive either methylene blue or control (n = 35/group).

RESULTS

Fewer patients received noradrenaline in the methylene blue group when compared with the control group (13/35 vs 23/35, P = 0.017), and the noradrenaline dose administrated during operation was reduced in the methylene blue group when compared with the control group (0.32 ± 0.57 mg vs 1.787 ± 3.51 mg, P = 0.018). The blood level of creatinine, glutamic oxalacetic transaminase, and glutamic-pyruvic transaminase after the operation was reduced in the methylene blue group when compared with the control group.

CONCLUSIONS

Prophylactic administration of methylene blue before operation associated with obstructive jaundice improves hemodynamic stability and short-term prognosis.

QUESTION

Methylene blue use prevented refractory hypotension during cardiac surgery, sepsis, or anaphylactic shock. It is still unknown that methylene blue on the vascular hypo-tone associated with obstructive jaundice.

FINDINGS

Prophylactic administration with methylene blue improved peri-operative hemodynamic stability, and hepatic and kidney function on the patients with obstructive jaundice.

MEANINGS

Methylene blue is a promising and recommended drug for the patients undergoing the surgeries of relief obstructive jaundice during peri-operation management.

Early Serial Echocardiographic and Ultrasonographic Findings in Critically Ill Patients With COVID-19

Background

Cardiac function of critically ill patients with COVID-19 generally has been reported from clinically obtained data. Echocardiographic deformation imaging can identify ventricular dysfunction missed by traditional echocardiographic assessment.

Research Question

What is the prevalence of ventricular dysfunction and what are its implications for the natural history of critical COVID-19?

Study Design and Methods

This is a multicenter prospective cohort of critically ill patients with COVID-19. We performed serial echocardiography and lower extremity vascular ultrasound on hospitalization days 1, 3, and 8. We defined left ventricular (LV) dysfunction as the absolute value of longitudinal strain of < 17% or left ventricle ejection fraction (LVEF) of < 50%. Primary clinical outcome was inpatient survival.

Results

We enrolled 110 patients. Thirty-nine (35.5%) died before hospital discharge. LV dysfunction was present at admission in 38 patients (34.5%) and in 21 patients (36.2%) on day 8 (P = .59). Median baseline LVEF was 62% (interquartile range [IQR], 52%-69%), whereas median absolute value of baseline LV strain was 16% (IQR, 14%-19%). Survivors and nonsurvivors did not differ statistically significantly with respect to day 1 LV strain (17.9% vs 14.4%; P = .12) or day 1 LVEF (60.5% vs 65%; P = .06). Nonsurvivors showed worse day 1 right ventricle (RV) strain than survivors (16.3% vs 21.2%; P = .04).

Interpretation

Among patients with critical COVID-19, LV and RV dysfunction is common, frequently identified only through deformation imaging, and early (day 1) RV dysfunction may be associated with clinical outcome.

Initiating angiotensin II at lower vasopressor doses in vasodilatory shock: an exploratory post-hoc analysis of the ATHOS-3 clinical trial

BACKGROUND

High dose vasopressors portend poor outcome in vasodilatory shock. We aimed to evaluate the impact of baseline vasopressor dose on outcomes in patients treated with angiotensin II (AT II).

METHODS

Exploratory post-hoc analysis of the Angiotensin II for the Treatment of High-Output Shock (ATHOS-3) trial data. The ATHOS-3 trial randomized 321 patients with vasodilatory shock, who remained hypotensive (mean arterial pressure of 55-70 mmHg) despite receiving standard of care vasopressor support at a norepinephrine-equivalent dose (NED) > 0.2 µg/kg/min, to receive AT II or placebo, both in addition to standard of care vasopressors. Patients were grouped into low (≤ 0.25 µg/kg/min; n = 104) or high (> 0.25 µg/kg/min; n = 217) NED at the time of study drug initiation. The primary outcome was the difference in 28-day survival between the AT II and placebo subgroups in those with a baseline NED ≤ 0.25 µg/kg/min at the time of study drug initiation.

RESULTS

Of 321 patients, the median baseline NED in the low-NED subgroup was similar in the AT II (n = 56) and placebo (n = 48) groups (median of each arm 0.21 µg/kg/min, p = 0.45). In the high-NED subgroup, the median baseline NEDs were also similar (0.47 µg/kg/min AT II group, n = 107 vs. 0.45 µg/kg/min placebo group, n = 110, p = 0.75). After adjusting for severity of illness, those randomized to AT II in the low-NED subgroup were half as likely to die at 28-days compared to placebo (HR 0.509; 95% CI 0.274-0.945, p = 0.03). No differences in 28-day survival between AT II and placebo groups were found in the high-NED subgroup (HR 0.933; 95% CI 0.644-1.350, p = 0.71). Serious adverse events were less frequent in the low-NED AT II subgroup compared to the placebo low-NED subgroup, though differences were not statistically significant, and were comparable in the high-NED subgroups.

CONCLUSIONS

This exploratory post-hoc analysis of phase 3 clinical trial data suggests a potential benefit of AT II introduction at lower doses of other vasopressor agents. These data may inform design of a prospective trial.

TRIAL REGISTRATION

The ATHOS-3 trial was registered in the clinicaltrials.gov repository (no. NCT02338843). Registered 14 January 2015.

A PILOT STUDY OF ANGIOTENSIN II AS PRIMARY VASOPRESSOR IN CRITICALLY ILL ADULTS WITH VASODILATORY HYPOTENSION: THE ARAMIS STUDY

ABSTRACT

Objective: The aim of the study is to evaluate the efficacy and safety of using angiotensin II (Ang2) as primary vasopressor for vasodilatory hypotension. Methods: This was a prospective observational study of critically ill adults admitted to an academic intensive care unit (ICU) with vasodilatory hypotension. We treated 40 patients with Ang2 as primary vasopressor and compared them with 80 matched controls who received conventional vasopressors (norepinephrine, vasopressin, metaraminol, epinephrine, or combinations). Results : Mean age was 63 years and median Acute Physiology and Chronic Health Evaluation III score was 65. Ang2 patients had lower ICU mortality (10% vs 26%, P = 0.04); however, their 28- and 90-day mortality was not significantly different (18% vs 29%, P = 0.18; 22% vs 30%, P = 0.39). Peak serum creatinine levels were similar (128 vs 126 μmol/L, P = 0.81), as was the incidence and stage of acute kidney injury (70% vs 74%, P = 0.66), requirement for continuous renal replacement therapy (14% vs 13%, P = 0.84), and risk of major adverse kidney events at 7 days (20% vs 29%, P = 0.30). However, Ang2 patients with prior exposure to renin angiotensin aldosterone system inhibitors had a lower peak serum creatinine ( P = 0.03 for interaction) than conventional vasopressors patients, and serum troponin elevations were less common with Ang2 (8% vs 22%, P = 0.04). The incidence of thromboembolic complications was similar. Conclusions: Primary Ang2 administration in vasodilatory hypotension did not seem harmful compared with conventional vasopressors. Although Ang2 did not decrease peak serum creatinine levels or major adverse kidney events, its effects on intensive care unit survival, serum troponin, and renal function in patients on renin angiotensin aldosterone system inhibitors warrant further exploration in randomized trials (ACTRN12621000281897).

Tendency of dynamic vasoactive and inotropic medications data as a robust predictor of mortality in patients with septic shock: An analysis of the MIMIC-IV database

Background

Septic shock patients fundamentally require delicate vasoactive and inotropic agent administration, which could be quantitatively and objectively evaluated by the vasoactive–inotropic score (VIS); however, whether the dynamic trends of high-time-resolution VIS alter the clinical outcomes remains unclear. Thus, this study proposes the term VIS Reduction Rate (VRR) to generalise the tendency of dynamic VIS, to explore the association of VRR and mortality for patients with septic shock.

Methods

We applied dynamic and static VIS data to predict ICU mortality by two models: the long short-term memory (LSTM) deep learning model, and the extreme gradient boosting (XGBoost), respectively. The specific target cohort was extracted from the Medical Information Mart for Intensive Care IV (MIMIC-IV) database by the sophisticated structured query language (SQL). Enrolled patients were divided into four groups by VRR value: ≥50%, 0 ~ 50%, −50% ~ 0, and &lt; −50%. Statistical approaches included pairwise propensity score matching (PSM), Cox proportional hazards regression, and two doubly robust estimation models to ensure the robustness of the results. The primary and secondary outcomes were ICU mortality and in-hospital mortality, respectively.

Results

VRR simplifies the dosing trends of vasoactive and inotropic agents represented by dynamic VIS data while requiring fewer data. In total, 8,887 septic shock patients were included. Compared with the VRR ≥50% group, the 0 ~ 50%, −50% ~ 0, and &lt; −50% groups had significantly higher ICU mortality [hazard ratio (HR) 1.32, 95% confidence interval (CI) 1.17–1.50, p &lt; 0.001; HR 1.79, 95% CI 1.44–2.22, p &lt; 0.001; HR 2.07, 95% CI 1.61–2.66, p &lt; 0.001, respectively] and in-hospital mortality [HR 1.43, 95% CI 1.28–1.60, p &lt; 0.001; HR 1.75, 95% CI 1.45–2.11, p &lt; 0.001; HR 2.00, 95% CI 1.61–2.49, p &lt; 0.001, respectively]. Similar findings were observed in two doubly robust estimation models.

Conclusion

The trends of dynamic VIS in ICU might help intensivists to stratify the prognosis of adult patients with septic shock. A lower decline of VIS was remarkably associated with higher ICU and in-hospital mortality among septic shock patients receiving vasoactive–inotropic therapy for more than 24 h.

Not all Shock States Are Created Equal: A Review of the Diagnosis and Management of Septic, Hypovolemic, Cardiogenic, Obstructive, and Distributive Shock

Shock in the critically ill patient is common and associated with poor outcomes. Categories include distributive, hypovolemic, obstructive, and cardiogenic, of which distributive (and usually septic distributive) shock is by far the most common. Clinical history, physical examination, and hemodynamic assessments & monitoring help differentiate these states. Specific management necessitates interventions to correct the triggering etiology as well as ongoing resuscitation to maintain physiologic milieu. One shock state may convert to another and may have an undifferentiated presentation; therefore, continual re-assessment is essential. This review provides guidance for intensivists for management of all shock states based on available scientific evidence.

[Fluid and vasopressor therapy in sepsis]

Sepsis is one of the most common and lethal conditions in intensive care medicine. Besides adequate treatment of the infection, timely hemodynamic management is essential to treat tissue hypoperfusion due to sepsis. Adequate fluid resuscitation plays a central role, and this should be carried out with dynamic monitoring of the hemodynamic response. However, a positive fluid balance is associated with poor outcome. Vasopressor therapy is required in case of inadequate response to fluid resuscitation, with norepinephrine considered the first choice. With increasing norepinephrine dose, addition of hydrocortisone or vasopressin may contribute to maintaining the hemodynamic state, although the prognostic advantage of these drugs has not been demonstrated. While dobutamine may be considered in patients with septic cardiomyopathy, the evidence for inotropic therapy in sepsis is limited.

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.

An updated "norepinephrine equivalent" score in intensive care as a marker of shock severity

Vasopressors and fluids are the cornerstones for the treatment of shock. The current international guidelines on shock recommend norepinephrine as the first-line vasopressor and vasopressin as the second-line vasopressor. In clinical practice, due to drug availability, local practice variations, special settings, and ongoing research, several alternative vasoconstrictors and adjuncts are used in the absence of precise equivalent doses. Norepinephrine equivalence (NEE) is frequently used in clinical trials to overcome this heterogeneity and describe vasopressor support in a standardized manner. NEE quantifies the total amount of vasopressors, considering the potency of each such agent, which typically includes catecholamines, derivatives, and vasopressin. Intensive care studies use NEE as an eligibility criterion and also an outcome measure. On the other hand, NEE has several pitfalls which clinicians should know, important the lack of conversion of novel vasopressors such as angiotensin II and also adjuncts such as methylene blue, including a lack of high-quality data to support the equation and validate its predictive performance in all types of critical care practice. This review describes the history of NEE and suggests an updated formula incorporating novel vasopressors and adjuncts.

How Effective is Angiotensin II in Decreasing Mortality of Vasodilatory Shock? A Systematic Review

Background

Patients with severe vasodilation accompanied by refractory hypotension despite high doses of vasopressors were associated with a high mortality rate. The Ang-2 for the Treatment of High-Output Shock (ATHOS) 3 trial demonstrated that angiotensin 2 (Ang-2) could effectively increase MAP and blood pressure in vasodilatory shock patients. This systematic review aims to summarize the impact of Ang-2 for the treatment of vasodilatory shock on clinical outcomes, including length of stay, MAP level (before and after), and mortality also Ang-2 dose needed.

Methods

A systematic search in PubMed, Sage, ScienceDirect, Scopus and Gray literature was conducted to obtain studies about the use of Ang-2 in vasodilatory shock patients.

Results

In all of the studies that we obtained, there were different results regarding mortality in patients with vasodilatory shock with Ang-2. Mortality was significantly lower when Ang-2 was administered to patients with elevated renin. The initial dose of Ang-2 can be started at 10-20 ng/kg/min, but there is no agreement on the maximum dose. Ang-2 may be considered a third-line vasopressor if the targeted MAP has not been achieved after administration of norepinephrine >200 ng/kg/min for more than 6 hours. Although not statistically significant, the use of Ang-2 can reduce the length of stay in the ICU and in the hospital when compared to patients without Ang-2 therapy, in addition to reducing the dose of vasopressor.

Conclusion

Overall, the use of Ang-2 has potential to be a regimen for patients with vasodilatory shock. Further study is needed to obtain more data.

Angiotensin II for Vasodilatory Hypotension in Patients Requiring Mechanical Circulatory Support

Background: Patients supported on mechanical circulatory support devices experience vasodilatory hypotension due to high surface area exposure to nonbiological and non-endothelialized surfaces. Angiotensin II has been studied in general settings of vasodilatory shock, however concerns exist regarding the use of this vasopressor in patients with pre-existing cardiac failure. The objective of this study was to assess the systemic and central hemodynamic effects of angiotensin II in patients with primary cardiac or respiratory failure requiring treatment with mechanical circulatory support devices. Methods: Multicenter retrospective observational study of adults supported on a mechanical circulatory support device who received angiotensin II for vasodilatory shock. The primary outcome was the intraindividual change from baseline in mean arterial pressure (MAP) and vasopressor dosage after angiotensin II. Results: Fifty patients were included with mechanical circulatory devices that were primarily used for cardiac failure (n = 41) or respiratory failure (n = 9). At angiotensin II initiation, the norepinephrine equivalent vasopressor dosage was 0.44 (0.34, 0.64) and 0.47 (0.33, 0.73) mcg/kg/min in the cardiac and respiratory groups, respectively. In the cardiac group, MAP increased from 60 to 70 mmHg (intraindividual P < .001) in the 1 h after angiotensin II initiation and the vasopressor dosage declined by 0.04 mcg/kg/min (intraindividual P < .001). By 12 h, the vasopressor dosage declined by 0.16 mcg/kg/min ( P = .001). There were no significant changes in cardiac index or mean pulmonary artery pressure throughout the 12 h following angiotensin II. In the respiratory group, similar but nonsignificant effects at 1 h on MAP (61-81 mmHg, P = .26) and vasopressor dosage (decline by 0.13 mcg/kg/min, P = .06) were observed. Conclusions: In patients requiring mechanical circulatory support for cardiac failure, angiotensin II produced beneficial systemic hemodynamic effects without negatively impacting cardiac function or pulmonary pressures. The systemic hemodynamic effects in those with respiratory failure were nonsignificant due to limited sample size.

Early versus delayed enteral nutrition in mechanically ventilated patients with circulatory shock: a nested cohort analysis of an international multicenter, pragmatic clinical trial

Introduction

Real-world evidence on the timing and efficacy of enteral nutrition (EN) practices in intensive care unit (ICU) patients with circulatory shock is limited. We hypothesized early EN (EEN), as compared to delayed EN (DEN), is associated with improved clinical outcomes in mechanically ventilated (MV) patients with circulatory shock.

Methods

We analyzed a dataset from an international, multicenter, pragmatic randomized clinical trial (RCT) evaluating protein dose in ICU patients. Data were collected from ICU admission, and EEN was defined as initiating < 48 h from ICU admission and DEN > 48 h. We identified MV patients in circulatory shock to evaluate the association between the timing of EN initiation and clinical outcomes. The regression analysis model controlled for age, mNUTRIC score, APACHE II score, sepsis, and Site.

Results

We included 626 patients, from 52 ICUs in 14 countries. Median age was 60 years [18–93], 55% had septic shock, 99% received norepinephrine alone, 91% received EN alone, and 50.3% were randomized to a usual protein dose. Forty-two percent of EEN patients had persistent organ dysfunction syndrome plus death at day 28, compared to 53% in the DEN group (p = 0.04). EEN was associated with more ICU-free days (9.3 ± 9.2 vs. 5.7 ± 7.9, p = 0.0002), more days alive and free of vasopressors (7.1 ± 3.1 vs. 6.3 ± 3.2, p = 0.007), and shorter duration of MV among survivors (9.8 ± 10.9 vs. 13.8 ± 14.5, p = 0.0002). This trend was no longer observed in the adjusted analysis. There were no differences in ICU/60-day mortality or feeding intolerance rates between groups.

Conclusion

In MV patients with circulatory shock, EEN, as compared to DEN, was associated with improved clinical outcomes, but no longer when adjusting for illness severity. RCTs comparing the efficacy of EEN to DEN in MV patients with circulatory shock are warranted.

Autonomic and circulatory alterations persist despite adequate resuscitation in a 5-day sepsis swine experiment

Autonomic and vascular failures are common phenotypes of sepsis, typically characterized by tachycardia despite corrected hypotension/hypovolemia, vasopressor resistance, increased arterial stiffness and decreased peripheral vascular resistance. In a 5-day swine experiment of polymicrobial sepsis we aimed at characterizing arterial properties and autonomic mechanisms responsible for cardiovascular homeostasis regulation, with the final goal to verify whether the resuscitation therapy in agreement with standard guidelines was successful in restoring a physiological condition of hemodynamic profile, cardiovascular interactions and autonomic control. Twenty pigs were randomized to polymicrobial sepsis and protocol-based resuscitation or to prolonged mechanical ventilation and sedation without sepsis. The animals were studied at baseline, after sepsis development, and every 24 h during the 3-days resuscitation period. Beat-to-beat carotid blood pressure (BP), carotid blood flow, and central venous pressure were continuously recorded. The two-element Windkessel model was adopted to study carotid arterial compliance, systemic vascular resistance and characteristic time constant τ. Effective arterial elastance was calculated as a simple estimate of total arterial load. Cardiac baroreflex sensitivity (BRS) and low frequency (LF) spectral power of diastolic BP were computed to assess autonomic activity. Sepsis induced significant vascular and autonomic alterations, manifested as increased arterial stiffness, decreased vascular resistance and τ constant, reduced BRS and LF power, higher arterial afterload and elevated heart rate in septic pigs compared to sham animals. This compromised condition was persistent until the end of the experiment, despite achievement of recommended resuscitation goals by administered vasopressors and fluids. Vascular and autonomic alterations persist 3 days after goal-directed resuscitation in a clinically relevant sepsis model. We hypothesize that the addition of these variables to standard clinical markers may better profile patients' response to treatment and this could drive a more tailored therapy which could have a potential impact on long-term outcomes.

VASOPRESSOR-RESISTANT HYPOTENSION, COMBINATION VASOPRESSOR THERAPY, AND SHOCK PHENOTYPES IN CRITICALLY ILL ADULTS WITH VASODILATORY SHOCK

ABSTRACT

Objective: To examine the risk factors, resource utilization, and 1-year mortality associated with vasopressor-resistant hypotension (VRH) compared with vasopressor-sensitive hypotension (VSH) among critically ill adults with vasodilatory shock. We also examined whether combination vasopressor therapy and patient phenotype were associated with mortality. Design: Retrospective cohort study. Setting: Eight medical-surgical intensive care units at the University of Pittsburgh Medical Center, Pittsburgh, PA. Patients : Critically ill patients with vasodilatory shock admitted between July 2000 and October 2008. Interventions : None. Measurements and Main Results: Vasopressor-resistant hypotension was defined as those requiring greater than 0.2 μg/kg per minute of norepinephrine equivalent dose of vasopressor consecutively for more than 6 h, and VSH was defined as patients requiring ≤0.2 μg/kg per minute to maintain MAP between 55 and 70 mm Hg after adequate fluid resuscitation. Of 5,313 patients with vasodilatory shock, 1,291 patients (24.3%) developed VRH. Compared with VSH, VRH was associated with increased risk of acute kidney injury (72.7% vs. 65.0%; P < 0.001), use of kidney replacement therapy (26.0% vs. 11.0%; P < 0.001), longer median (interquartile range [IQR]) intensive care unit length of stay (10 [IQR, 4.0-20.0] vs. 6 [IQR, 3.0-13.0] days; P < 0.001), and increased 1-year mortality (64.7% vs. 34.8%; P < 0.001). Vasopressor-resistant hypotension was associated with increased odds of risk-adjusted mortality (adjusted odds ratio [aOR], 2.93; 95% confidence interval [CI], 2.52-3.40; P < 0.001). When compared with monotherapy, combination vasopressor therapy with two (aOR, 0.91; 95% CI, 0.78-1.06) and three or more vasopressors was not associated with lower mortality (aOR, 0.93; 95% CI, 0.68-1.27). Using a finite mixture model, we identified four unique phenotypes of patient clusters that differed with respect to demographics, severity of illness, processes of care, vasopressor use, and outcomes. Conclusions: Among critically ill patients with vasodilatory shock, VRH compared with VSH is associated with increased resource utilization and long-term risk of death. However, combination vasopressor therapy was not associated with lower risk of death. We identified four unique phenotypes of patient clusters that require further validation.

Timing of vasoactive agents and corticosteroid initiation in septic shock

Septic shock remains a health care concern associated with significant morbidity and mortality. The Surviving Sepsis Campaign Guidelines for Management of Sepsis and Septic Shock recommend early fluid resuscitation and antimicrobials. Beyond initial management, the guidelines do not provide clear recommendations on appropriate time to initiate vasoactive therapies and corticosteroids in patients who develop shock. This review summarizes the literature regarding time of initiation of these interventions. Clinical data regarding time of initiation of these therapies in relation to shock onset, sequence of treatments with regard to each other, and clinical markers evaluated to guide initiation are summarized. Early-high vasopressor initiation within first 6 h of shock onset is associated with lower mortality. Following norepinephrine initiation, the exact dose and timing of escalation to adjunctive vasopressor agents are not well elucidated in the literature. However, recent data indicate that timing may be an important factor in initiating vasopressors and adjunctive therapies, such as corticosteroids. Norepinephrine-equivalent dose and lactate concentration can aid in determining when to initiate vasopressin and angiotensin II in patients with septic shock. Future guidelines with clear recommendations on the time of initiation of septic shock therapies are warranted.

Agreements between mean arterial pressure from radial and femoral artery measurements in refractory shock patients

Radial and femoral artery catheterization is the most common procedure for monitoring patients with shock. However, a disagreement in mean arterial pressure (MAP) between the two sites has been reported. Hence, the aim of this study was to compare the MAP from the radial artery (MAP_radial) with that of the femoral artery (MAP_femoral) in patients with refractory shock. A prospective study was conducted in the medical intensive care unit. The radial and femoral were simultaneously measured MAP in the patients every hour, for 24 h. In total, 706 paired data points were obtained from 32 patients. MAP_radial strongly correlated with MAP_femoral (r = 0.89, p < 0.0001). However, overall MAP_radial was significantly lower than MAP_femoral 7.6 mmHg. The bias between MAP_radial and MAP_femoral was − 7.6 mmHg (95% limits of agreement (LOA), − 24.1 to 8.9). In the subgroup of patients with MAP_radial < 65 mmHg, MAP_radial moderately correlated with MAP_femoral (r = 0.63) and the bias was increased to − 13.0 mmHg (95% LOA, − 28.8 to 2.9). There were 414 (58.6%) measurements in which the MAP gradient between the two sites was > 5 mmHg. In conclusion, the radial artery significantly underestimated MAP compared with the femoral artery in patients with refractory shock.

Improving nutrition practices for postoperative high-risk heart transplant and ventricular assist device implant patients in circulatory compromise: A quality improvement pre- and post-protocol intervention outcome study

BACKGROUND

Patients undergoing heart transplant (HT) and ventricular assist device (VAD) implant may experience intra- and postoperative complications requiring high-dose vasopressor agents and/or mechanical circulatory support. These complications increase the risk of nonocclusive bowel ischemia (NOBI) and inadequate enteral nutrition (EN) delivery, and guidance for this high-risk patient population is limited. To optimize nutrition support practices in this patient population at our institution, we created the High-Risk Nutrition Support Protocol (HRNSP) to improve nutrient delivery and promote safer EN practices in the setting of NOBI risk factors after HT and VAD implant.

METHODS

We developed and implemented a nutrition support protocol as a quality improvement (QI) initiative. Data were obtained before (n = 62) and after (n = 52) protocol initiation. We compared nutrition and clinical outcomes between the pre- and post-intervention groups.

RESULTS

Fewer calorie deficits (P < 0.001), fewer protein deficits (P < 0.001), a greater proportion of calorie/protein needs met (P < 0.001), zero NOBI cases (0%), and decreased intensive care unit (ICU) length of stay (LOS) (P = 0.005) were observed with 100% (n = 52 of 54) HRNSP implementation success. Increased use of parenteral nutrition did not increase central line-associated bloodstream infections (P = 0.46). There was no difference in hospital LOS (P = 0.44) or 90-day and 1-year mortality (P = 0.56, P = 0.35).

CONCLUSION

This single-center, QI pre- and post-protocol intervention outcome study suggests that implementing and adhering to a nutrition support protocol for VAD implant/HT patients with hemodynamic complications increases nutrient delivery and is associated with reduced ICU LOS and NOBI.

Protocol Compliance Guiding Angiotensin II Use in Post Cardiovascular Surgery Vasoplegia

Catecholamines and vasopressin are commonly used in patients with post cardiovascular surgery vasoplegia (PCSV). Multimodal therapy, including methylene blue (MB), hydroxocobalamin, and angiotensin II (Ang II), may improve outcomes in patients who remain hypotensive despite catecholamine and vasopressin therapy. However, a standardized approach has not been established. We created a protocol at Emory Healthcare (Emory Protocol), which provides guidance on norepinephrine equivalent dose (NED) and the use of noncatecholamines in the setting of PCSV and sought to determine the clinical significance of adherence to the protocol.

Effects of methylene blue on microcirculatory alterations following cardiac surgery: A prospective cohort study

BACKGROUND

Methylene blue is used as rescue therapy to treat catecholamine-refractory vasoplegic syndrome after cardiac surgery. However, its microcirculatory effects remain poorly documented.

OBJECTIVE

We aimed to study microcirculatory abnormalities in refractory vasoplegic syndrome following cardiac surgery with cardiopulmonary bypass and assess the effects of methylene blue.

DESIGN

A prospective open-label cohort study.

SETTING

20-Bed ICU of a tertiary care hospital.

PATIENTS

25 Adult patients receiving 1.5 mg kg-1 of methylene blue intravenously for refractory vasoplegic syndrome (defined as norepinephrine requirement more than 0.5 μg kg-1 min-1) to maintain mean arterial pressure (MAP) more than 65 mmHg and cardiac index (CI) more than 2.0 l min-1 m-2.

MAIN OUTCOME MEASURES

Complete haemodynamic set of measurements at baseline and 1 h after the administration of methylene blue. Sublingual microcirculation was investigated by sidestream dark field imaging to obtain microvascular flow index (MFI), total vessel density, perfused vessel density and heterogeneity index. Microvascular reactivity was assessed by peripheral near-infrared (IR) spectroscopy combined with a vascular occlusion test. We also performed a standardised measurement of capillary refill time.

RESULTS

Despite normalised CI (2.6 [2.0 to 3.8] l min-1 m-2) and MAP (66 [55 to 76] mmHg), patients with refractory vasoplegic syndrome showed severe microcirculatory alterations (MFI < 2.6). After methylene blue infusion, MFI significantly increased from 2.0 [0.1 to 2.5] to 2.2 [0.2 to 2.8] (P = 0.008), as did total vessel density from 13.5 [8.3 to 18.5] to 14.9 [10.1 to 14.7] mm mm-2 (P = 0.02) and perfused vessel density density from 7.4 [0.1 to 11.5] to 9.1 [0 to 20.1] mm mm-2 (P = 0.02), but with wide individual variation. Microvascular reactivity assessed by tissue oxygen resaturation speed also increased from 0.5 [0.1 to 1.8] to 0.7 [0.1 to 2.7]% s-1 (P = 0.002). Capillary refill time remained unchanged throughout the study.

CONCLUSION

In refractory vasoplegic syndrome following cardiac surgery, we found microcirculatory alterations despite normalised CI and MAP. The administration of methylene blue could improve microvascular perfusion and reactivity, and partially restore the loss of haemodynamic coherence.

TRIAL REGISTRATION

ClinicalTrials.gov identifier: NCT04250389.

The Epidemiology of Extremity Threat and Amputation after Vasopressor-Dependent Sepsis

Rationale: Extremity threat and amputation after sepsis is a well-publicized and devastating event. However, there is a paucity of data about the epidemiology of extremity threat after sepsis onset. Objectives: To estimate the incidence of extremity threat with or without surgical amputation in community sepsis. Methods: Retrospective cohort study of adults with Sepsis-3 hospitalized at 14 academic and community sites from 2013 to 2017. Vasopressor-dependent sepsis was identified by administration of epinephrine, norepinephrine, phenylephrine, vasopressin, or dopamine for more than 1 hour during the 48 hours before to 24 hours after sepsis onset. Outcomes included the incidence of extremity threat, defined as acute onset ischemia, with or without amputation, in the 90 days after sepsis onset. The association between extremity threat, demographics, comorbid conditions, and time-varying sepsis treatments was evaluated using a Cox proportional hazards model. Results: Among 24,365 adults with sepsis, 12,060 (54%) were vasopressor dependent (mean ± standard deviation age, 64 ± 16 years; male, 6,548 [54%]; sequential organ failure assessment [SOFA], 10 ± 4). Of these, 231 (2%) patients had a threatened extremity with 26 undergoing 37 amputations, a risk of 2.2 (95% confidence interval [CI], 1.4-3.2) per 1,000, and 205 not undergoing amputation, a risk of 17.0 (95% CI, 14.8-19.5) per 1,000. Most amputations occurred in lower extremities (95%), a median (interquartile range) of 16 (6-40) days after sepsis onset. Compared with patients with no extremity threat, patients with threat had a higher SOFA score (11 ± 4 vs. 10 ± 4; P < 0.001), serum lactate (4.6 mmol/L [2.4-8.7] vs. 3.1 [1.7-6.0]; P < 0.001), and more bacteremia (n = 37 [37%] vs. n = 2,087 [26%]; P < 0.001) at sepsis onset. Peripheral vascular disease, congestive heart failure, SOFA score, and norepinephrine equivalents were significantly associated with extremity threat. Conclusions: The evaluation of a threatened extremity resulting in surgical amputation occurred in 2 per 1,000 patients with vasopressor-dependent sepsis.

Vasopressor Choice and Timing in Vasodilatory Shock

This article is one of ten reviews selected from the Annual Update in Intensive Care and Emergency Medicine 2022. Other selected articles can be found online at https://www.biomedcentral.com/collections/annualupdate2022 . Further information about the Annual Update in Intensive Care and Emergency Medicine is available from https://link.springer.com/bookseries/8901 .

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

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

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.

A Multicenter Observational Cohort Study of Angiotensin II in Shock

INTRODUCTION

Angiotensin II (Ang-2) is a non-catecholamine vasopressor that targets the renin-angiotensin-aldosterone system by agonism of the angiotensin type 1 receptor. Its utility as a vasopressor and a catecholamine-sparing agent was demonstrated in the pivotal ATHOS-3 trial, and numerous post-hoc analyses have shown reduced mortality in certain subsets of the population.

METHODS

Consecutive adult patients at 5 centers who received Ang-2 from 2017-2020 were included in this multicenter, retrospective observational cohort study. Patient demographics, hemodynamics, and adverse events were collected. The primary outcomes of the study were the mean difference in MAP and norepinephrine (NEpi)-equivalent dose at hours 0 and 3 following initiation of Ang-2 therapy.

RESULTS

One hundred and sixty-two patients were included in this study. The primary outcomes of an increase in MAP (mean difference 9.3 mmHg, 95% CI 6.4-12.1, p < 0.001) and a reduction in NEpi equivalent dose (mean difference 0.16 µg/kg/min, 95% CI 0.10-0.22, p < 0.001) between hours 0 and 3 were statistically significant. The median time to reach a MAP ≥65 was 16 minutes (IQR 5-60 min). After stratifying patients by the NED dose and number of vasopressors administered prior to the initiation of Ang-2, those with a NED dose < 0.2 µg/kg/min, NED dose < 0.3 µg/kg/min, or those on ≤ 3 vasopressors had a significantly greater reduction in NED by hour 3 than those patients above these thresholds.

CONCLUSION

Ang-2 is an effective vasopressor and reduces catecholamine dose significantly. Its effect is rapid, with target MAP obtained within 30 minutes in most patients. Given the critical importance of adequate blood pressure to organ perfusion, Ang-2 should be considered when target MAP cannot be achieved with conventional vasopressors. Ang-2 should be utilized early in the course of shock, before the NED dose exceeds 0.2-0.3 µg/kg/min and before the initiation of the fourth-line vasopressor.

Beyond the bundle: Clinical controversies in the management of sepsis in emergency medicine patients

Sepsis is a condition characterized by life-threatening organ dysfunction caused by a dysregulated host response to infection. The emergency department (ED) serves as a crucial entry point for patients presenting with sepsis. Given the heterogeneous presentation and high mortality rate associated with sepsis and septic shock, several clinical controversies have emerged in the management of sepsis. These include the use of novel therapeutic agents like angiotensin II, hydrocortisone, ascorbic acid, thiamine ("HAT") therapy, and levosimendan, Additionally, controversies with current treatments in vasopressor dosing, and the use of and balanced or unbalanced crystalloid are crucial to consider. The purpose of this review is to discuss clinical controversies in the management of septic patients, including the use of novel medications and dosing strategies, to assist providers in appropriately determining what treatment strategy is best suited for patients.

Effects of a single bolus of hydroxocobalamin on hemodynamics in vasodilatory shock

PURPOSE

Hydroxocobalamin has been observed to cause transient hypertension in healthy subjects, but rigorous studies examining its efficacy are lacking.

MATERIALS AND METHODS

Adults in shock who received hydroxocobalamin from 2017 to 2021 were analyzed retrospectively. Hourly hemodynamics from 24 h before and after treatment were collected, and the difference and hourly change of mean arterial pressure (MAP), systolic blood pressure (SBP), diastolic blood pressure (DBP), and norepinephrine-equivalent dose (NED) were examined in mixed-effects models.

RESULTS

This study included 3992 hemodynamic data points from 35 patients and is the largest case series to date. In the mixed effects model, there was no difference in MAP 24-h after hydroxocobalamin administration (estimated fixed effect [EFE] -0.2 mmHg, p = 0.89). A two-piecewise mixed model found that the hourly change in MAP was not different from zero in either the pre-administration (EFE 0.0 mmHg/h, p = 0.80) or post-administration segments (EFE 0.0 mmHg/h, p = 0.55). Analysis of the SBP, DBP, and NED also found similar insignificant results.

CONCLUSIONS

Although hydroxocobalamin has been observed to cause hypertension in healthy subjects, our results suggest that in patients with shock, hydroxocobalamin may not be effective in improving hemodynamics at 24 h after administration.

Antihypertensive Medications Prior to Shock Onset Do Not Impact Initial Vasopressor Requirements in Patients With Shock

Purpose: The effect of the use of antihypertensive agents in patients prior to the development of shock is unclear. The purpose of this study was to determine the impact of antihypertensive agents on vasopressor dose and duration in shock. Materials and Methods: This retrospective, single-center study included patients with shock who received at least one vasopressor for at least 24 hours after shock onset from January 1 to June 30, 2017. Patients taking an antihypertensive agent(s) were compared to those who were not. The primary outcome was the number of vasopressor-free hours at 72 hours. Secondary outcomes included maximum and cumulative vasopressor doses, intensive care unit length of stay, and 30-day mortality. Results: One hundred and sixty-eight patients were included and 99 (59%) were on antihypertensives. Distributive shock was the most common type of shock (75.5%) and more patients taking antihypertensives had hypertension, coronary artery disease, and dyslipidemia at baseline. There was no difference in the number of vasopressor-free hours at 72 hours between patients taking an antihypertensive medication(s) and the control group (2 hours vs 1 hour; P = .11). No difference was found between any of the secondary outcomes. Conclusion: Patients taking antihypertensive agents prior to shock onset did not require increased vasopressor doses or duration.

Clinical impact of visually assessed right ventricular dysfunction in patients with septic shock

We retrospectively analyzed data from the Medical Information Mart for Intensive Care-III critical care database to determine whether visually-assessed right ventricular (RV) dysfunction was associated with clinical outcomes in septic shock patients. Associations between visually-assessed RV dysfunction by echocardiography and in-hospital mortality, lethal arrhythmia, and hemodynamic indicators to determine the prognostic value of RV dysfunction in patients with septic shock were analyzed. Propensity score analysis showed RV dysfunction was associated with increased risk of in-hospital death in patients with septic shock (adjusted odds ratio [OR] 2.15; 95% confidence interval [CI] 1.99–2.32; P < 0.001). In multivariate logistic regression analysis, RV dysfunction was associated with in-hospital death (OR 2.19; 95% CI 1.91–2.53; P < 0.001), lethal arrhythmia (OR 2.19; 95% CI 1.34–3.57; P < 0.001), and tendency for increased blood lactate levels (OR 1.31; 95% CI 1.14–1.50; P < 0.001) independent of left ventricular (LV) dysfunction. RV dysfunction was associated with lower cardiac output, pulmonary artery pressure index, and RV stroke work index. In patients with septic shock, visually-assessed RV dysfunction was associated with in-hospital mortality, lethal arrhythmia, and circulatory insufficiency independent of LV dysfunction. Visual assessment of RV dysfunction using echocardiography might help to identify the short-term prognosis of patients with septic shock by reflecting hemodynamic status.

Effects of Propofol on Hemodynamic Profile in Adults Receiving Targeted Temperature Management

Background: Propofol is a key component for the management of sedation and shivering during targeted temperature management (TTM) following cardiac arrest. The cardiac depressant effects of propofol have not been described during TTM and may be especially relevant given the stress to the myocardium following cardiac arrest. The purpose of this study is to describe hemodynamic changes associated with propofol administration during TTM. Methods: This single center, retrospective cohort study evaluated adult patients who received a propofol infusion for at least 30 minutes during TTM. The primary outcome was the change in cardiovascular Sequential Organ Failure Assessment (cvSOFA) score 30 minutes after propofol initiation. Secondary outcomes included change in systolic blood pressure (SBP), mean arterial pressure (MAP), heart rate (HR), and vasopressor requirements (VR) expressed as norepinephrine equivalents at 30, 60, 120, 180, and 240 minutes after propofol initiation. A multivariate regression was performed to assess the influence of propofol and body temperature on MAP, while controlling for vasopressor dose and cardiac arrest hospital prognosis (CAHP) score. Results: The cohort included 40 patients with a median CAHP score of 197. The goal temperature of 33°C was achieved for all patients. The median cvSOFA score was 1 at baseline and 0.5 at 30 minutes, with a non-significant change after propofol initiation ( P = .96). SBP and MAP reductions were the greatest at 60 minutes (17 and 8 mmHg; P < .05 for both). The median change in HR at 120 minutes was −9 beats/minute from baseline. This reduction was sustained through 240 minutes ( P < .05). No change in VR were seen at any time point. In multivariate regression, body temperature was the only characteristic independently associated with changes in MAP (coefficient 4.95, 95% CI 1.6-8.3). Conclusion: Administration of propofol during TTM did not affect cvSOFA score. The reductions in SBP, MAP, and HR did not have a corresponding change in vasopressor requirements and are likely not clinically meaningful. Propofol appears to be a safe choice for sedation in patients receiving targeted temperature management after cardiac arrest.

Evaluation of Vasopressor Exposure and Mortality in Patients With Septic Shock

OBJECTIVES

The objectives of this study were to: 1) determine the association between vasopressor dosing intensity during the first 6 hours and first 24 hours after the onset of septic shock and 30-day in-hospital mortality; 2) determine whether the effect of vasopressor dosing intensity varies by fluid resuscitation volume; and 3) determine whether the effect of vasopressor dosing intensity varies by dosing titration pattern.

DESIGN

Multicenter prospective cohort study between September 2017 and February 2018. Vasopressor dosing intensity was defined as the total vasopressor dose infused across all vasopressors in norepinephrine equivalents.

SETTING

Thirty-three hospital sites in the United States (n = 32) and Jordan (n = 1).

PATIENTS

Consecutive adults requiring admission to the ICU with septic shock treated with greater than or equal to 1 vasopressor within 24 hours of shock onset.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

Out of 1,639 patients screened, 616 were included. Norepinephrine (93%) was the most common vasopressor. Patients received a median of 3,400 mL (interquartile range, 1,851-5,338 mL) during the 24 hours after shock diagnosis. The median vasopressor dosing intensity during the first 24 hours of shock onset was 8.5 μg/min norepinephrine equivalents (3.4-18.1 μg/min norepinephrine equivalents). In the first 6 hours, increasing vasopressor dosing intensity was associated with increased odds ratio of 30-day in-hospital mortality, with the strength of association dependent on concomitant fluid administration. Over the entire 24 hour period, every 10 μg/min increase in vasopressor dosing intensity was associated with an increased risk of 30-day mortality (adjusted odds ratio, 1.33; 95% CI, 1.16-1.53), and this association did not vary with the amount of fluid administration. Compared to an early high/late low vasopressor dosing strategy, an early low/late high or sustained high vasopressor dosing strategy was associated with higher mortality.

CONCLUSIONS

Increasing vasopressor dosing intensity during the first 24 hours after septic shock was associated with increased mortality. This association varied with the amount of early fluid administration and the timing of vasopressor titration.

The autonomic nervous system in septic shock and its role as a future therapeutic target: a narrative review

The autonomic nervous system (ANS) regulates the cardiovascular system. A growing body of experimental and clinical evidence confirms significant dysfunction of this regulation during sepsis and septic shock. Clinical guidelines do not currently include any evaluation of ANS function during the resuscitation phase of septic shock despite the fact that the severity and persistence of ANS dysfunction are correlated with worse clinical outcomes. In the critical care setting, the clinical use of ANS-related hemodynamic indices is currently limited to preliminary investigations trying to predict and anticipate imminent clinical deterioration. In this review, we discuss the evidence supporting the concept that, in septic shock, restoration of ANS-mediated control of the cardiovascular system or alleviation of the clinical consequences induced by its dysfunction (e.g., excessive tachycardia, etc.), may be an important therapeutic goal, in combination with traditional resuscitation targets. Recent studies, which have used standard and advanced monitoring methods and mathematical models to investigate the ANS-mediated mechanisms of physiological regulation, have shown the feasibility and importance of monitoring ANS hemodynamic indices at the bedside, based on the acquisition of simple signals, such as heart rate and arterial blood pressure fluctuations. During the early phase of septic shock, experimental and/or clinical studies have shown the efficacy of negative-chronotropic agents (i.e., beta-blockers or ivabradine) in controlling persistent tachycardia despite adequate resuscitation. Central α-2 agonists have been shown to prevent peripheral adrenergic receptor desensitization by reducing catecholamine exposure. Whether these new therapeutic approaches can safely improve clinical outcomes remains to be confirmed in larger clinical trials. New technological solutions are now available to non-invasively modulate ANS outflow, such as transcutaneous vagal stimulation, with initial pre-clinical studies showing promising results and paving the way for ANS modulation to be considered as a new potential therapeutic target in patients with septic shock.

Hitting the Vasopressor Ceiling: Finding Norepinephrine Associated Mortality in the Critically Ill

BACKGROUND

There is no consensus on what dose of norepinephrine corresponds with futility. The purpose of this study was to investigate the maximum infusion and cumulative doses of norepinephrine associated with survival for patients in medical and surgical intensive care units (MICU and SICU).

MATERIALS AND METHODS

A retrospective review was conducted of 661 critically ill patients admitted to a large academic medical center who received norepinephrine. Univariate, multivariate, and area under the curve analyses with optimal cut offs for maximum infusion rate and cumulative dosage were determined by Youden Index.

RESULTS

The population was 54.9% male, 75.8% white, and 58.7 ± 16.1 y old with 384 (69.8%) admitted to the MICU and 166 (30.2%) admitted to the SICU, including 38 trauma patients. Inflection points in mortality were seen at 18 mcg/min and 17.6 mg. The inflection point was higher in MICU patients at 21 mcg/min and lower in SICU patients at 11 mcg/min. MICU patients also had a higher maximum cumulative dosage of 30.7 mg, compared to 2.7 mg in SICU patients. In trauma patients, norepinephrine infusions up to 5 mcg/min were associated with a 41.7% mortality rate.

CONCLUSION

A maximum rate of 18 mcg/min and cumulative dose of 17.6 mg were the inflection points for mortality risk in ICU patients, with SICU patients tolerating lower doses. In trauma patients, even low doses of norepinephrine were associated with higher mortality. These data suggest that MICU, SICU, and trauma patients differ in need for, response to, and outcome from escalating norepinephrine doses.

Effects of Norepinephrine Infusion on Cutaneous Surface Temperatures of the Distal Extremities

OBJECTIVES

The etiology of vasopressor-induced digital necrosis is poorly understood, but the skin changes resemble those of frostbite, and it is known from experience that patients taking vasopressors have decreased digital temperatures. We aimed to examine the effects of norepinephrine use on surface temperatures of the distal extremities because there have been no studies examining this relation.

METHODS

Surface temperatures of all digits, palms, and soles were measured using an infrared thermometer in patients receiving different rates of norepinephrine infusion in the intensive care unit and compared with those not receiving any vasopressors.

RESULTS

A total of 101 measurements from 41 unique individuals were obtained. Temperature gradients between the core and the fingertips were consistently more pronounced in those receiving norepinephrine compared with those not receiving norepinephrine and increased with increasing rates of norepinephrine infusion, except with high-dose norepinephrine. Temperature gradients were more pronounced in the toes.

CONCLUSIONS

Norepinephrine use was associated with greater core-to-fingertip temperature gradients and were more pronounced in the toes compared with the fingers.

Acute kidney injury after lung transplantation: a narrative review

Acute kidney injury (AKI) is a commonly recognized complication after lung transplantation (LT) and is related to increased mortality and morbidity. With the improvement of survival after LT and the increasing number of lung transplant recipients, the detrimental impact of current management on renal function has become increasingly apparent. Multifarious risk factors in the perioperative setting contribute to the development of AKI, including the preoperative status and complications of the recipient, complex perioperative problems especially hemodynamic fluctuation, and exposure to nephrotoxic agents, mainly calcineurin inhibitors (CNIs) and antimicrobial drugs. Identification and minimization of the effects of these risk factors can relieve AKI severity and incidence in high-risk patients. Close monitoring of urine output and serum creatinine (sCr) levels and of specific biomarkers may promote early recognition of AKI and rapid nephrology intervention to improve outcomes. This review summarizes advances in the epidemiology, diagnostic criteria, biological markers of AKI, and further recommends appropriate treatment strategies for the long-term management of AKI related manifestations in lung transplant recipients. Future work will need to focus on developing more accurate measures of renal function and identifying patients before the occurrence of early renal damage. Combining renal protection strategies with the use of new biomarkers to develop early kidney risk identification and protection protocols is a promising idea that requires further investigation.

A time-sensitive analysis of the prognostic utility of vasopressor dose in septic shock

It is unclear whether the association between vasopressor dose and mortality is affected by duration of administration. We examined whether prognostication in septic shock is feasible through the use of daily median vasopressor doses. We undertook a single-centre retrospective cohort study. We included patients with a diagnosis of septic shock admitted to the intensive care unit at Queen Elizabeth Hospital, Birmingham, UK, between April 2016 and July 2019. The primary outcome measure was 90-day mortality. We defined vasopressor dose as the median norepinephrine equivalent dose (equivalent infusion rates of all vasopressors and inotropes) recorded for each day, for the first four days of septic shock. We divided patients into groups by vasopressor dose quintiles and calculated their 90-day mortality rate. We examined area under the receiver operator characteristic curves for prognostic ability. In total, 844 patients were admitted with septic shock and had a 90-day mortality of 43% (n = 358). Over the first four days, median vasopressor dose decreased in 93% of survivors and increased in 56% of non-survivors. The mortality rate associated with a given vasopressor dose quintile increased on sequential days of septic shock. The area under the receiver operator characteristic curves of daily median vasopressor dose against mortality increased from day 1 to day 4 (0.67 vs. 0.86, p < 0.0001). By day 4, a median daily vasopressor dose > 0.05 μg.kg^-1 .min^-1 had an 80% sensitivity and specificity for mortality. The prognostic utility of vasopressor dose improved considerably with shock duration. Prolonged administration of small vasopressor doses was associated with a high attributable mortality.

Extended Duration Infusion of Hydroxocobalamin for Vasoplegic Rescue in Septic Shock

Nitric oxide (NO) is a gaseous signaling molecule and a key endogenous mediator of vascular tone. Hydroxocobalamin (HCB) affects NO-mediated vasoplegia as (1) a direct inhibitor of nitric oxide synthase (NOS), thereby decreasing its production, and (2) by binding directly to NO and acting as a scavenger. HCB has been increasingly used in the treatment of refractory vasoplegia, particularly in cardiac surgery and liver transplant patients. Sepsis and septic shock are characterized by an increase in inducible NOS expression and activity with excessive NO production, resulting in endothelial dysfunction and profound systemic vasodilation. Therefore, a careful sustained reduction in NO burden represents a potential therapeutic target. Here, we present a case of refractory septic shock, which resolved after an extended duration infusion of high-dose HCB. We hope to foster further exploration regarding the safety, dosing, and efficacy of HCB when administered for vasopressor refractory septic shock.