Definitions and pathophysiology of vasoplegic shock

Effects of intravenous inflammasome inhibitor (NuSepin) on suppression of proinflammatory cytokines release induced by cardiopulmonary bypass in swine model: a pilot study

The systemic inflammatory response syndrome can occur due to an inflammatory reaction to the release of cytokines, and it has been linked to the circulation of pro- and anti-inflammatory cytokines. The cardiopulmonary bypass (CPB) system is known to activate numerous inflammatory pathways. Applying CPB in large animals for an extended period may be useful as a controlled experimental model for systemic inflammatory responses. The authors hypothesized that 0.2 mg/kg NuSepin® would inhibit CBP-induced proinflammatory cytokine release, and attenuate CPB-induced vasoplegia. CPB was maintained for 2 h in 8 male Yorkshire pigs. Ten ml of saline was administered intravenously to the control group, while the study group received 10 ml of NuSepin® (0.2 mg/kg), before start of CPB. Blood samples were collected at four different time points to evaluating the level of cytokine (TNF-α, IL-1β, IL-6, IL-8) release during and after CBP. All vital signals were recorded as continuous waveforms using the vital recorder®. Our study demonstrated that IL-6 increased in both groups during CPB remained unchanged. However, in the Nusepin group, IL-6 levels rapidly decreased when CPB was stopped and the proinflammatory reaction subsided. Furthermore, the dose of norepinephrine required to maintain a mean pressure of 60 mmHg was also lower in the Nusepin group.

Treatment of refractory shock with vitamin B12 : A narrative review

High-dose vitamin B12 is a potential treatment for patients with vasodilatory shock that is refractory to other therapies. Vasodilatory shock is characterized by low blood pressure and low systemic vascular resistance. Nitric oxide and hydrogen sulfide, two potential targets of high-dose vitamin B12 given as hydroxocobalamin, facilitate this syndrome. This review explores the relationship between high-dose vitamin B12 and hemodynamic outcomes in adults with vasodilatory shock and provides an update on the literature since a 2019 review on this topic. A literature search of studies published in the past 5 years was conducted in the CINAHL, PubMed, Cochrane, and EMBASE databases in May 2023. After assessing for eligibility, eight studies met this review's inclusion criteria. Seven of the eight studies reported decreased vasopressor requirements for part or all of the study samples after receiving a hydroxocobalamin infusion. However, not all patients responded to hydroxocobalamin. These findings are limited by patient selection and differences in the timing of vasopressor requirement and blood pressure outcome assessments. The current evidence is promising as to whether vitamin B12 , given as a hydroxocobalamin infusion, may improve hemodynamic outcomes in vasodilatory shock, but the evidence is of low quality. The use of hydroxocobalamin to treat refractory, vasodilatory shock remains investigative. Larger randomized controlled trials are required to elucidate the role of vitamin B12 in treating refractory, vasodilatory shock, including in conjunction with other alternative therapies such as methylene blue and corticosteroids.

Vascular Reactivity Index as an Effective Predictor of Mortality in Patients With Septic Shock: A Retrospective Study

BACKGROUND

Sepsis is a serious complication that occurs after trauma, burns, and infections, and it is an important cause of death in intensive care unit (ICU) patients. Despite many new measures being proposed for sepsis treatment, its mortality rate remains high; sepsis has become a serious threat to human health, and there is an urgent need to carry out in-depth clinical research related to sepsis. In recent years, it has been found that septic shock-induced vasoplegia is a result of vascular hyporesponsiveness to vasopressors. Therefore, this study intended to establish an objective formula related to vasoplegia that can be used to assess the prognosis of patients and guide clinical treatment.

MATERIALS AND METHODS

A retrospective cohort study was conducted using data from 106 septic shock patients admitted to the ICU of Jining No. 1 People's Hospital from January 2020 to December 2022. The patients were divided into mortality and survival groups based on 28-day survival, and hemodynamics were monitored by the pulse index continuous cardiac output system. The dose and duration of vasopressors, major hemodynamic parameters, lactic acid (Lac) levels, and Sequential Organ Failure Assessment scores were recorded within 48 h of hospital admission. Multifactorial logistic regression was used to analyze the independent risk factors affecting the prognosis of patients, and the predictive value of the vascular response index (VRI) was analyzed by the receiver operating characteristic (ROC) curve.

RESULTS

The differences between the survival and mortality groups in terms of age, sex ratio, body weight, ICU length of stay, distribution of infection sites, underlying disease conditions, baseline Lac levels, and some hemodynamic parameters were not statistically significant (P > .05). The results of multifactorial logistic regression showed that the admission Acute Physiology and Chronic Health Evaluation II score, Lac level at 24 h of treatment, maximal vasoactive inotropic score at 24 h (VISmax24), maximal vasoactive inotropic score at 48 h (VISmax48), and VRI were independent risk factors affecting 28-day mortality. Within 48 h of receiving vasopressor therapy, the VRI was lower in the mortality group than in the survival group. The area under the ROC curve for the VRI was 0.86, and the best cutoff value of the VRI for predicting 28-day mortality was 32.50 (YI = 0.80), with a sensitivity of 0.90, a specificity of 0.90, and a better prediction of mortality than the other indicators.

CONCLUSIONS

The VRI is a good predictor of mortality in patients with septic shock, and a lower VRI indicates more severe vasoplegia, poorer prognosis, and higher mortality in patients with septic shock.

Vasoplegia Following Complex Spine Surgery: Incidence and Risk

STUDY DESIGN

Retrospective cohort study.

OBJECTIVES

Vasoplegia is a life-threatening form of distributive or vasodilatory shock that is characterized by reduced systemic vascular resistance with resultant hypotension and normal to elevated cardiac output affecting morbidity and mortality. Vasoplegia in the context of Spine Surgery has not been described previously. The purpose of this case series is to determine incidence, risk factors, complications and postoperative outcome in patients with vasoplegia after complex multi-level thoraco-lumbar spine surgery.

METHODS

A retrospective review of the electronic medical records at our institution was conducted between January 2014 and June 2018. All patients undergoing multi-level spine surgery (>6 levels) were screened for intraoperative hypotension. Patient demographics, surgical characteristics, neurological status, blood loss, risk factors, medical treatment, complications, hospital course and mortality were collected. All patients included in this study had a minimum follow-up period of 3 months.

RESULTS

Out of 8521 surgically treated patients, 994 patients with multi-level thoraco-lumbar spine surgery were identified. A total of 41 patients had intraoperative hypotensive events. Of those, 5 patients with vasoplegia could be identified after elimination of all other potential contributing factors. Vasoplegia did not influence the neurological outcome. One major and three minor complications occurred. All patients showed full recovery. The risk factors identified for vasoplegia include prolonged surgery with osteotomies.

CONCLUSIONS

Vasoplegia is a rare condition with an incidence of .6%. Patients experiencing vasoplegia did not appear to experience worse surgical outcomes. The use of special intraoperative hemodynamic monitoring should be considered in selected cases.

Effect of methylene blue on outcomes in patients with distributive shock: a meta-analysis of randomised controlled trials

OBJECTIVE

This meta-analysis aimed to demonstrate the effect of methylene blue (MB) in patients with distributive shock.

DESIGN

Meta-analysis.

METHODS

According to the Prospective International Register of Systematic Reviews (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines, we searched the relevant randomised controlled trials (RCTs) via PubMed, Embase and Cochrane Library from the date of database inception to 19 April 2023. The primary outcome was mortality during follow-up, and secondary outcomes included mean arterial pressure (mm Hg), mechanical ventilation time (hours), intensive care unit (ICU) length of stay (LOS) (days), hospital LOS (days) and heart rate (times/min).

RESULTS

This study included six RCTs with 265 participants. The study showed no significant difference in mortality between the MB and placebo groups (ORs: 0.59; 95% CI 0.32 to -1.06). However, MB reduced the duration of mechanical ventilation (mean difference (MD): -0.68; 95% CI -1.23 to -0.14), ICU LOS (MD: -1.54; 95% CI -2.61 to -0.48) and hospital LOS (MD: -1.97; 95% CI -3.92 to -0.11).

CONCLUSIONS

The use of MB may not reduce mortality in patients with distributive shock, but may shorten the duration of mechanical ventilation, ICU LOS and hospital LOS. More clinical studies are needed to confirm these findings in the future.

TRIAL REGISTRATION NUMBER

CRD42023415938.

PERSUADE Survey-PERioperative AnestheSia and Intensive Care Management of Left VentricUlar Assist DevicE Implantation in Europe and the United States

OBJECTIVE

To comprehensively assess relevant institutional variations in anesthesia and intensive care management during left ventricular assist device (LVAD) implantation.

DESIGN

The authors used a prospective data analysis.

SETTING

This was an online survey.

PARTICIPANTS

Participants were from LVAD centers in Europe and the US.

INTERVENTIONS

After investigating initial interest, 91 of 202 European and 93 of 195 US centers received a link to the survey targeting institutional organization and experience, perioperative hemodynamic monitoring, medical management, and postoperative intensive care aspects.

MEASUREMENTS AND MAIN RESULTS

The survey was completed by 73 (36.1%) European and 60 (30.8%) US centers. Although most LVAD implantations were performed in university hospitals (>5 years of experience), significant differences were observed in the composition of the preoperative multidisciplinary team and provision of intraoperative care. No significant differences in monitoring or induction agents were observed. Propofol was used more often for maintenance in Europe (p < 0.001). The choice for inotropes changed significantly from preoperatively (more levosimendan in Europe) to intraoperatively (more use of epinephrine in both Europe and the US). The use of quantitative methods for defining right ventricular (RV) function was reported more often from European centers than from US centers (p < 0.05). Temporary mechanical circulatory support for the treatment of RV failure was more often used in Europe. Nitric oxide appeared to play a major role only intraoperatively. There were no significant differences in early postoperative complications reported from European versus US centers.

CONCLUSIONS

Although the perioperative practice of care for patients undergoing LVAD implantation differs in several aspects between Europe and the US, there were no perceived differences in early postoperative complications.

Leucoglycemic index predicts post-operative vasopressor-inotropic requirement after adult cardiac surgery (LEUCOGLYPTICS): A retrospective single-center study

Background and Aims

Cardiac surgery often necessitates considerable post-operative vasoactive-inotropic support. Given an encouraging literature on the prognostic potential of leucoglycemic index (LGI) [serum glucose (mg/dl) × total leucocytes count (cells/mm3)/1000], we aimed to evaluate whether intensive care unit (ICU)-admission LGI can predict post-operative vasopressor-inotropic requirements following cardiac surgery on cardio-pulmonary bypass (CPB).

Material and Methods

The data of patients undergoing cardiac surgery at our tertiary care center between January 2015 and December 2020 was retrospectively reviewed. The vasopressor-inotropic requirement was estimated using the VIS (vasoactive-inotropic score) values over the first post-operative 72 hrs. Subsequently, VISi (indexed VIS) was computed as maxVIS[0-24hrs] + maxVIS[24-48hrs] +2 × maxVIS[48-72hrs]/10), and the study participants were divided into h-VISi (VISi ≥3) and l-VISi (VISi <3).

Results

Out of 2138 patients, 479 (22.40%) patients categorized as h-VISi. On univariate analysis: LGI, age, European System for Cardiac Operative Risk Evaluation score (EuroSCORE II), left-ventricle ejection fraction, prior congestive heart failure (CHF), chronic renal failure, angiotensin-converting enzyme inhibitors, combined surgeries, CPB and aortic cross-clamp (ACC) duration, blood transfusion, and immediate post-operative glucose were significant h-VISi predictors. Subsequent to multi-variate analysis, the predictive performance of LGI (OR: 1.09; 95% CI: 1.03-1.14; P = 0.002) prior CHF (OR: 2.35; 95% CI: 1.44-3.82; P = 0.001), CPB time (OR: 1.08; 95% CI: 1.02-1.14; P = 0.019), ACC time (OR: 1.03; 95% CI: 1.02-1.04; P = 0.008), and EuroSCORE II (OR: 1.14; 95% CI: 1.06-1.21; P < 0.001) remained significant. With 1484.75 emerging as the h-VISi predictive cut-off, patients with LGI ≥ 1484.75 also had a higher incidence of vasoplegia, low-cardiac output syndrome, new-onset atrial fibrillation, acute kidney injury, and mortality. LGI additionally exhibited a significant positive correlation with duration of mechanical ventilation and ICU stay (R = 0.495 and 0.564, P value < 0.001).

Conclusion

An elevated LGI of greater than 1484.75 independently predicted a VISindex ≥3 following adult cardiac surgery on CPB.

Micro-lightguide spectrophotometry assessment of hepatic and intestinal microcirculation in endotoxemic rats during intravenous treatment with angiotensin II

INTRODUCTION

During septic shock, impairment of microcirculation leads to enhanced permeability of intestinal mucosa triggered by generalized vasodilation and capillary leak. Intravenous angiotensin II (AT-II) has been approved for the treatment of septic shock; however, no in-vivo data exist on the influence of AT-II on hepatic and intestinal microcirculation.

MATERIAL AND METHODS

Sixty male Lewis rats were randomly assigned to six study groups (each n = 10): sham, lipopolysaccharide-induced septic shock, therapy with low- or high-dose AT-II (50 or 100 ng/kg/min, respectively), and septic shock treated with low- or high-dose AT-II. After median laparotomy, hepatic and intestinal microcirculation measures derived from micro-lightguide spectrophotometry were assessed for 3 h and included oxygen saturation (SO2), relative blood flow (relBF) and relative hemoglobin level (relHb). Hemodynamic measurements were performed using a left ventricular conductance catheter, and blood samples were taken hourly to analyze blood gasses and systemic cytokines.

RESULTS

AT-II increased mean arterial pressure in a dose-dependent manner in both septic and non-septic animals (p < 0.001). Lower hepatic and intestinal SO2 (both p < 0.001) were measured in animals without endotoxemia who received high-dose AT-II treatment, however, significantly impaired cardiac output was also reported in this group (p < 0.001). In endotoxemic rats, hepatic relBF and relHb were comparable among the treatment groups; however, hepatic SO2 was reduced during low- and high-dose AT-II treatment (p < 0.001). In contrast, intestinal SO2 remained unchanged despite treatment with AT-II. Intestinal relBF (p = 0.028) and interleukin (IL)-10 plasma levels (p < 0.001) were significantly elevated during treatment with high-dose AT-II compared with low-dose AT-II.

CONCLUSIONS

A dose-dependent decrease of hepatic and intestinal microcirculation during therapy with AT-II in non-septic rats was observed, which might have been influenced by a corresponding reduction in cardiac output due to elevated afterload. While hepatic microcirculation was reduced during endotoxemia, no evidence for a reduction in intestinal microcirculation facilitated by AT-II was found. In contrast, both intestinal relBF and anti-inflammatory IL-10 levels were increased during high-dose AT-II treatment.

Acute Kidney Injury after Cardiac Surgery: Prediction, Prevention, and Management

Acute kidney injury (AKI) is a common complication in cardiac surgery patients, with a reported incidence of 20 to 30%. The development of AKI is associated with worse short- and long-term mortality, and longer hospital length of stay. The pathogenesis of cardiac surgery-associated AKI is poorly understood but likely involves an interplay between preoperative comorbidities and perioperative stressors. AKI is commonly diagnosed by using increases in serum creatinine or decreased urine output and staged using a standardized definition such as the Kidney Disease Improving Global Outcomes classification. Novel biomarkers under investigation may provide earlier detection and better prediction of AKI, enabling mitigating therapies early in the perioperative period. Recent clinical trials of cardiac surgery patients have demonstrated the benefit of goal-directed oxygen delivery, avoidance of hyperthermic perfusion and specific fluid and medication strategies. This review article highlights both advances and limitations regarding the prevention, prediction, and treatment of cardiac surgery-associated AKI.

Understanding yellow fever-associated myocardial injury: an autopsy study

BACKGROUND

Yellow fever (YF) is a viral hemorrhagic fever, endemic in parts of South America and Africa. There is scarce evidence about the pathogenesis of the myocardial injury. The objective of this study is to evaluate the cardiac pathology in fatal cases of YF.

METHODS

This retrospective autopsy study included cases from the São Paulo (Brazil) epidemic of 2017-2019. We reviewed medical records and performed cardiac tissue histopathological evaluation, electron microscopy, immunohistochemical assays, RT-qPCR for YF virus (YFV)-RNA, and proteomics analysis on inflammatory and endothelial biomarkers.

FINDINGS

Seventy-three confirmed YF cases with a median age of 48 (34-60) years were included. We observed myocardial fibrosis in 68 (93.2%) patients; cardiomyocyte hypertrophy in 68 (93.2%); endothelial alterations in 67 (91.8%); fiber necrosis in 50 (68.5%); viral myocarditis in 9 (12.3%); and secondary myocarditis in 5 (6.8%). Four out of five patients with 17DD vaccine-associated viscerotropic disease presented with myocarditis. The cardiac conduction system showed edema, hemorrhages and endothelial fibrinoid necrosis. Immunohistochemistry detected CD68-positive inflammatory interstitial cells and YFV antigens in endothelial and inflammatory cells. YFV-RNA was detected positive in 95.7% of the cardiac samples. The proteomics analysis demonstrated that YF patients had higher levels of multiple inflammatory and endothelial biomarkers in comparison to cardiovascular controls, and higher levels of interferon gamma-induced protein 10 (IP-10) in comparison to sepsis (p = 0.01) and cardiovascular controls (p < 0.001) in Dunn test.

INTERPRETATION

Myocardial injury is frequent in severe YF, due to multifactorial mechanisms, including direct YFV-mediated damage, endothelial cell injury, and inflammatory response, with a possible prominent role for IP-10.

FUNDING

This study was funded by Fundação de Amparo à Pesquisa do Estado de São Paulo, Bill and Melinda Gates Foundation, Conselho Nacional de Desenvolvimento Científico e Tecnológico, Coordenação de Aperfeiçoamento de Pessoal de Nível Superior.

The efficacy of dexmedetomidine for septic shock: A meta-analysis of randomized controlled trials

INTRODUCTION

The efficacy of dexmedetomidine was elusive for septic shock. This meta-analysis aimed to explore the efficacy of dexmedetomidine for septic shock.

METHODS

PubMed, EMbase, Web of science, EBSCO, and Cochrane library databases have been searched through October 2022 and we included randomized controlled trials reporting the effect of dexmedetomidine in patients with septic shock.

RESULTS

Five randomized controlled trials were included in the meta-analysis. Compared with control group for septic shock, dexmedetomidine treatment was able to substantially decrease Sequential Organ Failure Assessment score (mean difference [MD] = -0.99; 95% confidence interval [CI] = -1.14 to -0.84; P < .00001) and duration of mechanical ventilation (MD = -0.90; 95% CI = -1.27 to -0.54; P < .00001), but showed no obvious influence on morality at 28 days (odds ratio = 0.79; 95% CI = 0.38 to 1.66; P = 054), hospital mortality (odds ratio = 0.66; 95% CI = 0.35 to 1.24; P = .20) or intensive care unit length of stay (MD = -1.47; 95% CI = -4.60 to 1.66; P = .36).

CONCLUSIONS

Dexmedetomidine administration may help treat patients with septic shock.

Vasoplegic Syndrome and Anaesthesia: A Narrative Review

Vasoplegic syndrome (VS) is defined as low systemic vascular resistance, normal or high cardiac output, and resistant hypotension unresponsive to vasopressor agents and intravenous volume. VS is a frequently encountered complication in cardiovascular and transplantation surgery, burns, trauma, pancreatitis, and sepsis. The basis of the pathophysiology is associated with an imbalance of vasodilator and vasoconstrictive structure in vascular smooth muscle cells and is highly complex. The pathogenesis of VS has several mechanisms, including overproduction of iNO, stimulation of ATP-dependent K+ channels and NF-κB, and vasopressin receptor 1A (V1A-receptor) down-regulation. Available treatments involve volume and inotropes administration, vasopressin, methylene blue, hydroxocobalamin, Ca++, vitamin C, and thiamine, and should also restore vascular tone and improve vasoplegia. Other treatments could include angiotensin II, corticosteroids, NF-κB inhibitor, ATP-dependent K+ channel blocker, indigo carmine, and hyperbaric oxygen therapy. Despite modern advances in treatment, the mortality rate is still 30-50%. It is challenging for an anaesthesiologist to consider this syndrome's diagnosis and manage its treatment. Our review aims to review the diagnosis, predisposing factors, pathophysiology, treatment, and anaesthesia approach of VS during anaesthesia and to suggest a treatment algorithm.

Different Types of Intraoperative Hypotension and their Association with Post-Anesthesia Care Unit Recovery

Background

The underlying causative mechanism leading to intraoperative hypotension (IOH) may vary depending on the stage of anesthesia and surgery, resulting in different types of IOH. Consequently, the incidence, severity, and postoperative complications associated with IOH types may differ. This study explores the association between IOH types and post-anesthesia care unit (PACU) recovery, with a focus on duration and complications.

Methods

From May 2022 to December 2022, we included 4776 consecutive surgical patients aged ≥18 who underwent elective surgery with planned overnight stays at Acibadem Altunizade Hospital and received general anesthesia. Post-induction hypotension (pIOH) was defined as a decrease in blood pressure during the first 20 minutes after anesthesia induction, while maintenance intraoperative hypotension (mIOH) referred to a decrease in blood pressure occurring after the 20th minute following induction, with or without preceding pIOH.

Results

Among the included patients, 22.13% experienced IOH, with a higher prevalence observed among females. Patients with mIOH exhibited higher rates of bleeding, transfusions, hypothermia, longer stays in the PACU, and increased oxygen requirements. The duration of anesthesia did not increase the likelihood of IOH. Multivariate logistic regression analysis revealed that ephedrine usage, hypothermia, the need for additional analgesics, nausea, and vomiting were factors associated with longer PACU duration. Older patients (≥65), patients with ASA≥2 status, those undergoing major surgery, experiencing unexpected bleeding, and exhibiting hypothermia at the end of anesthesia had a higher likelihood of requiring vasopressor support.

Conclusions

Patients experiencing hypotension, particularly during the maintenance of anesthesia, are more prone to complications in the PACU and require closer monitoring and treatment. Although less common, mIOH has a more significant impact on outcomes compared to other factors affecting PACU recovery. The impact of mIOH on PACU duration should not be overlooked in favor of other factors.

Registration

Clinicaltrials.gov identifier: NCT05671783.

Pulmonary, circulatory and renal considerations in the early postoperative management of the lung transplant recipient

Lung transplantation volumes and survival rates continue to increase worldwide. Primary graft dysfunction (PGD) and acute kidney injury (AKI) are common early postoperative complications that significantly affect short-term mortality and long-term outcomes. These conditions share overlapping risk factors and are driven, in part, by circulatory derangements. The prevalence of severe PGD is up to 20% and is the leading cause of early death. Patients with pulmonary hypertension are at a higher risk. Prevention and management are based on principles learned from acute lung injury of other causes. Targeting the lowest effective cardiac filling pressure will reduce alveolar edema formation in the setting of increased pulmonary capillary permeability. AKI is reported in up to one-half of lung transplant recipients and is strongly associated with one-year mortality as well as long-term chronic kidney disease. Optimization of renal perfusion is critical to reduce the incidence and severity of AKI. In this review, we highlight key early post-transplant pulmonary, circulatory, and renal perturbations and our center's management approach.

Vasoplegia: A Review

Vasoplegia is a condition characterized by persistent low systemic vascular resistance despite a normal or high cardiac index, resulting in profound and uncontrolled vasodilation. Vasoplegia may occur due to various conditions, including cardiac failure, sepsis, and post-cardiac surgery. In the cardiac cohort, multiple risk factors for vasoplegia have been identified. Several factors contribute to the pathophysiology of this condition, and various mechanisms have been proposed, including nitric oxide, adenosine, prostanoids, endothelins, the renin-angiotensin-aldosterone system, and hydrogen sulfide. Early identification and prompt management of vasoplegia is crucial to prevent development of shock. This review expands upon the different vasopressors used in management of vasoplegia, including catecholamines such as norepinephrine, dopamine, epinephrine, phenylephrine, and other agents including vasopressin, methylene blue, angiotensin II, hydroxocobalamin, vitamin C, thiamine, and corticosteroids (ie, hydrocortisone). It also emphasizes the importance of conducting further research and making advancements in treatment regimens for vasoplegia.

Adjunctive Vasopressors in Patients with Septic Shock: Protocol for a Systematic Review and Meta-Analysis

Background

Over one-third of patients with septic shock have adjunctive vasopressors added to first-line vasopressors. However, no randomized trial has detected improved mortality with adjunctive vasopressors. Published systematic reviews and meta-analysis have sought to inform the use of adjunctive vasopressors, yet each published review has limitations that hinder its interpretation. This review aims to overcome the limitations of previous reviews by systematically synthesizing the direct evidence for adjunctive vasopressor therapy use in adult patients with septic shock.

Methods

We will conduct a systematic review and meta-analysis of randomized controlled trials evaluating adjunctive vasopressors (vasopressin analogues, angiotensin II, hydroxocobalamin, methylene blue, and catecholamine analogues) in adult patients with septic shock. Relevant studies will be identified through comprehensive searches of MEDLINE, Embase, CENTRAL, and reference lists of previous systematic reviews. Only randomized trials comparing adjunctive vasopressors (>75% of subjects on vasopressors at enrollment) to standard care vasopressors in adults with septic shock (>75% of subjects having septic shock) will be included. Titles and abstracts will be screened, full-text articles assessed for eligibility, and data extracted from included studies. Outcomes of interest include short-term mortality, intermediate-term mortality, kidney replacement therapy, digital/peripheral ischemia, and venous thromboembolism. Pairwise meta-analysis using a random-effects model will be utilized to estimate the risk ratio for the outcomes. Risk of bias will be adjudicated with the Cochrane Risk of Bias 2 tool, and GRADE will be used to rate the certainty of the body of evidence.

Discussion

Although adjunctive vasopressors are commonly used in patients with septic shock their effect on patient-important outcomes is unclear. This study is planned to use rigorous systematic review methodology, including strict adhere to established guidelines, in order to overcome limitations of previously-published reviews and inform clinical practice and treatment guidelines for the use of adjunctive vasopressors in adults with septic shock.

Systematic review registration

PROSPERO CRD4202327984.

[Distributive shock]

In shock there is a significant mismatch between oxygen supply and consumption. In recent years the classification of forms of shock has been established based on pathophysiological and clinical aspects. The term distributive shock includes septic, anaphylactic and neurogenic shock. All these forms share a distinct vasoplegia with a relative volume deficiency. The adequate treatment of patients with distributive shock includes a rapid diagnosis and a consistent emergency treatment consisting of volume and catecholamine administration as well as additional specific emergency procedures when necessary.

Multidetector CT Imaging Biomarkers as Predictors of Prognosis in Shock: Updates and Future Directions

A severe mismatch between the supply and demand of oxygen is the common sequela of all types of shock, which present a mortality of up to 80%. Various organs play a protective role in shock and contribute to whole-body homeostasis. The ever-increasing number of multidetector CT examinations in severely ill and sometimes unstable patients leads to more frequently encountered findings leading to imminent death, together called "hypovolemic shock complex". Features on CT include dense opacification of the right heart and major systemic veins, venous layering of contrast material and blood, densely opacified parenchyma in the right hepatic lobe, decreased enhancement of the abdominal organ, a dense pulmonary artery, contrast pooling in dependent lungs, and contrast stasis in pulmonary veins. These findings are biomarkers and prognostic indicators of paramount importance which stratify risk and improve patient outcomes. In this review, we illustrate the various CT patterns in shock and review the spectrum and prognostic significance of thoraco-abdominal vascular and visceral alarming signs of impending death with the intention of increasing awareness among radiologists and radiographers to prepare for immediate resuscitation when required.

Successful Use of Methylene Blue in Catecholamine-Resistant Septic Shock: A Case Report and Short Literature Review

Despite efforts to improve treatment outcomes, mortality in septic shock remains high. In some patients, despite the use of several adrenergic drugs, features of refractory vasoplegic shock with progressive multiorgan failure are observed. We present a case report of the successful reversal of vasoplegic shock following the use of methylene blue, a selective inhibitor of the inducible form of nitric oxide synthase, which prevents vasodilation in response to inflammatory cytokines. We also briefly review the literature.

Impact of time to diagnosis on the occurrence of cardiogenic shock in MIS-C post-COVID-19 infection

BACKGROUND

In multisystem inflammatory syndrome in children (MIS-C), diagnostic delay could be associated with severity. This study aims to measure the time to diagnosis in MIS-C, assess its impact on the occurrence of cardiogenic shock, and specify its determinants.

METHODS

A single-center prospective cohort observational study was conducted between May 2020 and July 2022 at a tertiary care hospital. Children meeting the World Health Organization MIS-C criteria were included. A long time to diagnosis was defined as six days or more. Data on time to diagnosis were collected by two independent physicians. The primary outcome was the occurrence of cardiogenic shock. Logistic regression and receiver operating characteristic curve analysis were used for outcomes, and a Cox proportional hazards model was used for determinants.

RESULTS

Totally 60 children were assessed for inclusion, and 31 were finally analyzed [52% males, median age 8.8 (5.7-10.7) years]. The median time to diagnosis was 5.3 (4.2-6.2) days. In univariable analysis, age above the median, time to diagnosis, high C-reactive protein, and high N-terminal pro-B-type natriuretic peptide (NT-proBNP) were associated with cardiogenic shock [odds ratio (OR) 6.13 (1.02-36.9), 2.79 (1.15-6.74), 2.08 (1.05-4.12), and 1.70 (1.04-2.78), respectively]. In multivariable analysis, time to diagnosis ≥ 6 days was associated with cardiogenic shock [adjusted OR (aOR) 21.2 (1.98-227)]. Time to diagnosis ≥ 6 days had a sensitivity of 89% and a specificity of 77% in predicting cardiogenic shock; the addition of age > 8 years and NT-proBNP at diagnosis ≥ 11,254 ng/L increased the specificity to 91%. Independent determinants of short time to diagnosis were age < 8.8 years [aHR 0.34 (0.13-0.88)], short distance to tertiary care hospital [aHR 0.27 (0.08-0.92)], and the late period of the COVID-19 pandemic [aHR 2.48 (1.05-5.85)].

CONCLUSIONS

Time to diagnosis ≥ 6 days was independently associated with cardiogenic shock in MIS-C. Early diagnosis and treatment are crucial to avoid the use of inotropes and limit morbidity, especially in older children.

Cardiovascular Subphenotypes in ARDS: Diagnostic and Therapeutic Implications and Overlap with Other ARDS Subphenotypes

Acute respiratory distress syndrome (ARDS) is a highly heterogeneous clinical condition. Shock is a poor prognostic sign in ARDS, and heterogeneity in its pathophysiology may be a barrier to its effective treatment. Although right ventricular dysfunction is commonly implicated, there is no consensus definition for its diagnosis, and left ventricular function is neglected. There is a need to identify the homogenous subgroups within ARDS, that have a similar pathobiology, which can then be treated with targeted therapies. Haemodynamic clustering analyses in patients with ARDS have identified two subphenotypes of increasingly severe right ventricular injury, and a further subphenotype of hyperdynamic left ventricular function. In this review, we discuss how phenotyping the cardiovascular system in ARDS may align with haemodynamic pathophysiology, can aid in optimally defining right ventricular dysfunction and can identify tailored therapeutic targets for shock in ARDS. Additionally, clustering analyses of inflammatory, clinical and radiographic data describe other subphenotypes in ARDS. We detail the potential overlap between these and the cardiovascular phenotypes.

Hydroxocobalamin as Rescue Therapy in a Patient With Refractory Amlodipine-Induced Vasoplegia

Vasoplegic syndrome is a type of distributive shock characterized by mean arterial pressure of less than 65 mmHg, with normal to high cardiac output and often refractory to fluid resuscitation, high doses of intravenous vasopressors, and inotropes. It is usually observed after cardiac and solid organ transplantation surgeries. Here, we report a 56-year-old female patient who presented with a profound vasoplegia manifesting as lethargy and confusion in the setting of amlodipine toxicity. This case of severe vasoplegia was refractory to all conditional lines of medical management reported in the literature. The mainstay treatment modalities for vasoplegia include volume resuscitation, catecholamines, vasopressin, angiotensin II, and possibly methylene blue in unresponsive cases. Our patient was given hydroxocobalamin in favor of methylene blue, given the history of serotonin reuptake inhibitors use, which would have caused a life-threatening serotonin syndrome. Hydroxycobolamine resulted in a dramatic clinical recovery, suggesting its potentially significant role in refractory vasoplegia.

Estrogen ameliorates sepsis-induced vascular hyporeactivity in thoracic aorta of female rats via permissive effect of GRα expression

OBJECTIVE

Estrogen is correlated to the lower mortality and disease severity of female than that of male, which indicates the potential therapeutic role of estrogen supplement therapy in sepsis. The structure of Daidzein is similar to that of 17β estradiol (E₂), an estrogen in human body, causing the exogenous Daidzein can interact with estrogen receptor as well as E₂ in the body. We aim to explore the therapeutic role of estrogen in sepsis-induced vascular dysfunction. Also, we wonder if estrogen regulates blood pressure via glucocorticoid-mediated vascular reactivity.

METHODS

Female SD rats received ovariectomy (OVX) to induce estrogen deficiency. After 12 weeks of administration, cecal ligation and puncture (CLP) was used to establish the in vivo model of sepsis. Lipopolysaccharide (LPS) was used to construct the in vitro model of sepsis in vascular smooth muscle cells (VSMCs). E₂ and Daidzein were used for estrogen supplement therapy.

RESULTS

E₂ and Daidzein significantly inhibited inflammation infiltration and histopathological injury in thoracic aorta in the rat model with CLP. E₂ and Daidzein improved carotid pressure and vascular hyporeactivity in sepsis rats with OVX. Importantly, E₂ and Daidzein promoted glucocorticoid permissive action and increased glucocorticoid receptor α (GRα) expression in thoracic aorta smooth muscle cells. E₂ and Daidzein upregulated GRα, and inhibits cytokine production, proliferative phenotype and cell migration in LPS-induced VSMCs.

CONCLUSION

Estrogen improved vascular hyporeactivity in thoracic aorta induced by sepsis via permissive effect of GRα expression.

Postoperative vasoplegia in lung transplantation: incidence and relation to outcome

BACKGROUND

The incidence and clinical importance of vasoplegia after lung transplantation remains poorly studied. We describe the incidence of vasoplegia and its association with complications after lung transplantation.

METHODS

Perioperative data of 279 lung transplant recipients operated on from 2015 to 2020 were retrospectively analysed.

RESULTS

Vasoplegia occurred in 41.6% of patients after lung transplantation (mild, 31.0%; moderate, 55.2%; severe, 13.8%). Compared with non-vasoplegic patients, vasoplegic patients had a higher incidence of any acute kidney injury, defined by Kidney Disease Improving Global Outcomes (KDIGO) criteria (78.5% vs 65%, P=0.015), renal replacement therapy (47.4% vs 24.5%, P<0.001), and delayed chest closure (18.4% vs 9.2%, P=0.025); were ventilated longer (70 [32-368] vs 34 [19-105] h, P<0.001); and stayed longer in the ICU (12.9 [5-30] vs 6.8 [3-20] days, P<0.001). Mortality at 30 days and 1 yr was higher in patients with vasoplegia (11.2% vs 5.5% and 20.7% vs 11.7%, P=0.039, respectively). Severe vasoplegia represented a predictor of longer-term mortality (hazard ratio=1.65, P=0.008). Underlying infectious disease, increased BMI, higher preoperative pulmonary artery systolic pressure and bilirubin levels, lower glomerular filtration rate, and increased fresh frozen plasma transfusion were predictors of vasoplegia severity. Neutrophilia, leucocytosis, and increased C-reactive protein were associated with vasoplegia, but release of the neutrophil activation markers myeloperoxidase and heparin-binding protein was similar between groups.

CONCLUSIONS

Influenced by preoperative status as well as procedural factors and inflammatory response, vasoplegia is a common and critical condition after lung transplantation with worse short-term outcomes and long-term survival.

The incidence of postoperative vasopressor usage: protocol for a prospective international observational cohort study (SQUEEZE)

BACKGROUND

Postoperative hypotension is common after major non-cardiac surgery, due predominantly to vasodilation. Administration of infused vasopressors postoperatively may often be considered a surrogate indicator of vasodilation. The incidence of postoperative vasopressors has never been described for non-cardiac surgery, nor have outcomes associated with their use. This paper presents a protocol for a prospective international cohort study to address these gaps in knowledge. The primary objectives are to estimate the proportion of patients who receive postoperative vasopressor infusions (PVI) and to document the variation in this proportion between hospitals and internationally. Furthermore, we will identify factors in variation of care (patient, condition, surgery, and intraoperative management) associated with receipt of PVI and investigate how PVI use is associated with patient outcomes, including organ dysfunction, length of hospital stay, and 30-day in-hospital mortality.

METHOD

This will be a prospective, international, multicentre cohort study that includes all adult (≥ 18 years) non-cardiac surgical patients in participating centres. Patients undergoing cardiac, obstetric, or day-case surgery will be excluded. We will recruit two cohorts of patients: cohort A will include all eligible patients admitted to participating hospitals for seven consecutive days. Cohort B will include 30 sequential patients per hospital, with the single additional inclusion criterion of postoperative vasopressor usage. We expect to collect data on approximately 40,000 patients for cohort A and 12,800 patients for cohort B.

DISCUSSION

While in cardiac surgery, clinical trials have informed the choice of vasopressors used to treat postoperative vasoplegia; there remains equipoise over the best approach in non-cardiac surgery. Our study will represent the first large-scale assessment of the use of vasopressors after non-cardiac surgery. These data will inform future studies, including trials of different vasopressors and potential management options to improve outcomes and reduce resource use after surgery.

TRIAL REGISTRATION

ClinicalTrials.gov Identifier: NCT03805230, 15 January 2019.

[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.

Traumatic Brain Injury: Intraoperative Management and Intensive Care Unit Multimodality Monitoring

Traumatic brain injury is a devastating event associated with substantial morbidity. Pathophysiology involves the initial trauma, subsequent inflammatory response, and secondary insults, which worsen brain injury severity. Management entails cardiopulmonary stabilization and diagnostic imaging with targeted interventions, such as decompressive hemicraniectomy, intracranial monitors or drains, and pharmacological agents to reduce intracranial pressure. Anesthesia and intensive care requires control of multiple physiologic variables and evidence-based practices to reduce secondary brain injury. Advances in biomedical engineering have enhanced assessments of cerebral oxygenation, pressure, metabolism, blood flow, and autoregulation. Many centers employ multimodality neuromonitoring for targeted therapies with the hope to improve recovery.

MiRNA-30d and miR-770-5p as potential clinical risk predictors of Vasoplegic Syndrome in Patients undergoing on-pump coronary artery bypass grafting

The aims of this study were to perform pre-surgery miRNA profiling of patients who develop Vasoplegic syndrome (VS) after coronary artery bypass grafting (CABG) and identify those miRNAs that could be used as VS prognostic tools and biomarkers. The levels of 754 microRNAs (miRNAs) were measured in whole blood samples from a cohort of patients collected right before the coronary artery bypass grafting (CABG) surgery. We compared the miRNA levels of those who developed VS (VASO group) with those who did not (NONVASO group) after surgery. Six miRNAs (hsa-miR-548c-3p, -199b-5p, -383-5p -571 -183-3p, -30d-5p) were increased and two (hsa-1236-3p, and hsa-miR770-5p) were decreased in blood of VASO compared to NONVASO groups. Receiver Operating Characteristic (ROC) curve analysis revealed that a combination of the miRNAs, hsa-miR-30d-5p and hsa-miR-770-5p can be used as VS predictors (AUC = 0.9615, p < 0.0001). The computational and functional analyses were performed to gain insights into the potential role of these dysregulated miRNAs in VS and have identified the "Apelin Liver Signaling Pathway" as the canonical pathway containing the most target genes regulated by these miRNAs. The expression of the combined miRNAs hsa-miR-30d and hsa-miR-770-5p allowed the ability to distinguish between patients who could and could not develop VS, representing a potential predictive biomarker of VS.

High-Dose IV Hydroxocobalamin (Vitamin B12) in Septic Shock: A Double-Blind, Allocation-Concealed, Placebo-Controlled Single-Center Pilot Randomized Controlled Trial (The Intravenous Hydroxocobalamin in Septic Shock Trial)

BACKGROUND

Elevated hydrogen sulfide (H₂S) contributes to vasodilatation and hypotension in septic shock, and traditional therapies do not target this pathophysiologic mechanism. High-dose IV hydroxocobalamin scavenges and prevents H₂S formation, which may restore vascular tone and may accentuate recovery. No experimental human studies have tested high-dose IV hydroxocobalamin in adults with septic shock.

RESEARCH QUESTION

In adults with septic shock, is comparing high-dose IV hydroxocobalamin with placebo feasible?

STUDY DESIGN AND METHODS

We conducted a phase 2 single-center, double-blind, allocation-concealed, placebo-controlled, parallel-group pilot randomized controlled trial comparing high-dose IV hydroxocobalamin with placebo in critically ill adults with septic shock. Patients meeting Sepsis 3 criteria were randomized 1:1 to receive a single 5-g dose of high-dose IV hydroxocobalamin or equivalent volume 0.9% saline solution as placebo. The primary outcome was study feasibility (enrollment rate, clinical and laboratory compliance rate, and contamination rate). Secondary outcomes included between-group differences in plasma H₂S concentrations and vasopressor dose before and after infusion.

RESULTS

Twenty patients were enrolled over 19 months, establishing an enrollment rate of 1.05 patients per month. Protocol adherence rates were 100% with zero contamination. In the high-dose IV hydroxocobalamin group, compared to placebo, there was a greater reduction in vasopressor dose between randomization and postinfusion (-36% vs 4%, P < .001) and randomization and 3-h postinfusion (-28% vs 10%, P = .019). In the high-dose IV hydroxocobalamin group, the plasma H₂S level was reduced over 45 mins by -0.80 ± 1.73 μM, as compared with -0.21 ± 0.64 μM in the placebo group (P = .3).

INTERPRETATION

This pilot trial established favorable feasibility metrics. Consistent with the proposed mechanism of benefit, high-dose IV hydroxocobalamin compared with placebo was associated with reduced vasopressor dose and H₂S levels at all time points and without serious adverse events. These data provide the first proof of concept for feasibility of delivering high-dose IV hydroxocobalamin in septic shock.

TRIAL REGISTRY

ClinicalTrials.gov; No.: NCT03783091; URL: www.

CLINICALTRIALS

gov.

Review of Postoperative Care for Heart Transplant Recipients

The early postoperative management strategies after heart transplantation include optimizing the function of the denervated heart, correcting the causes of hemodynamic instability, and initiating and maintaining immunosuppressive therapy, allograft rejection surveillance, and prophylaxis against infections caused by immunosuppression. The course of postoperative support is influenced by the quality of allograft myocardial protection prior to implantation and reperfusion, donor-recipient heart size matching, surgical technique of orthotopic heart transplantation, and patient factors (eg, preoperative condition, immunologic compatibility, postoperative vasomotor tone, severity and reversibility of pulmonary vascular hypertension, pulmonary function, mediastinal blood loss, and end-organ perfusion). This review provides an overview of the early postoperative care of recipients and includes a brief description of the surgical techniques for orthotopic heart transplantation.

Oral midodrine does not expedite liberation from protracted vasopressor infusions: A case-control study

Vasopressor dependence is a common problem affecting patients in the recovery phase of critical illness, often necessitating intensive care unit (ICU) admission and other interventions which carry associated risks. Midodrine is an orally administered vasopressor which is commonly used off-label to expedite weaning from vasopressor infusions and facilitate discharge from ICU. We performed a single-centre, case-control study to assess whether midodrine accelerated liberation from vasopressor infusions in patients who were vasopressor dependent. Cases were identified at the discretion of treating intensivists and received 20 mg oral midodrine every eight h from enrolment. Controls received placebo. Data on duration and dose of vasopressor infusion, haemodynamics and adverse events were collected. Between 2012 and 2019, 42 controls and 19 cases were recruited. Cases had received vasopressor infusions for a median of 94 h versus 29.3 h for controls, indicating prolonged vasopressor dependence amongst cases. Midodrine use in cases was not associated with faster weaning of intravenous (IV) vasopressors (26 h versus 24 h for controls, P = 0.51), ICU or hospital length of stay after adjustment for confounders. Midodrine did not affect mean heart rate but was associated with bradycardia. This case-control study demonstrates that midodrine has limited efficacy in expediting weaning from vasopressor infusions in patients who have already received relatively prolonged courses of these infusions.

Clinical approach to vasoplegia in the transplant patient from the Pediatric Heart Transplant Society

This manuscript outlines a clinical approach to vasoplegia incorporating the current state of knowledge regarding vasoplegia in pediatric patients immediately post-transplant and to identify modifiable factors both pre- and post-transplant that may reduce post-operative morbidity, end-organ dysfunction, and mortality. Centers participating in the Pediatric Heart Transplant Society (PHTS) were asked to provide their internal protocols and rationale for vasoplegia management, and applicable adult and pediatric data were reviewed. The authors synthesized the above protocols and literature into the following description of clinical approaches to vasoplegia highlighting areas of both broad consensus and of significant practice variation.

Updates in the Management of Perioperative Vasoplegic Syndrome

Vasoplegic syndrome occurs relatively frequently in cardiac surgery, liver transplant, major noncardiac surgery, in post-return of spontaneous circulation situations, and in pateints with sepsis. It is paramount for the anesthesiologist to understand both the pathophysiology of vasoplegia and the different treatment strategies available for rescuing a patient from life-threatening hypotension.

Vascular Reactivity Index and PELOD-2 as a mortality predictor in paediatric septic shock: a single-centre retrospective study

BACKGROUND

The mortality rate for children with septic shock is stil quite high in low-income and middle-income countries (31.7%). One of the most widely used scoring systems to assess mortality in sepsis or septic shock is Paediatric Logistic Organ Dysfunction 2 (PELOD-2). However, it requires various laboratory evaluations. A non-invasive, fast and easy method is needed to assess the mortality of children with septic shock at an early stage. Therefore, this study aims to evaluate the ability of Vascular Reactivity Index (VRI) compared with PELOD-2 score as a predictor of mortality in children with septic shock based on vascular response to vasoactive agents.

METHODS

A retrospective cohort study was conducted using data from children aged 1 month to 18 years with septic shock treated in the ER and paediatric intensive care unit (PICU) of the tertiary hospital from 2017 to 2021. The serial haemodynamic data were analysed including Systemic Vascular Resistant Index (SVRI) and the cardiac index from ultrasound cardiac output monitoring device was recorded in the first and sixth hours after the diagnosis of septic shock. The VRI was determined by dividing SVRI/Vasoactive Inotropic Score (ie, accumulated doses of dopamine, dobutamine, epinephrine, milrinone, vasopressin and norepinephrine). The receiver operating curve was used to calculate the area under the curve (AUC), sensitivity and specificity of each cut-off point.

RESULTS

A total of 68 subjects fulfilled the inclusion and exclusion criteria, the median age was 54 months with a range of 2-204 months and the mortality rate was 47%. The majority of the patients who died were found in the high cardiac index and low SVRI group (17.6%). Moreover, the optimum cut-off point of VRI was obtained to predict mortality in septic shock of 32.1, with 87.5% sensitivity and 88.9% specificity. The AUC for predicting death using VRI was 95% (95% CI 90% to 100%, p<0.001) and PELOD-2 92.6% (95% CI 96.4% to 98.8%, p<0.001).

CONCLUSION

The VRI <32.1 may potentially be used to predict mortality in children with septic shock and its predictive ability is as good as PELOD-2. The assessment of VRI is faster and easier than PELOD-2.

Enteral gabexate mesilate improves volume requirements and autonomic cardiovascular function after experimental trauma/hemorrhagic shock in the absence of blood reperfusion

The standard of care for fluid resuscitation of trauma/hemorrhagic shock (T/HS) is the infusion of blood. However, in many instances, blood product transfusion may not be feasible. Consequently, crystalloid solutions may be utilized as temporizing cost-effective resuscitation fluids. In this study, we explored an alternative therapeutic strategy of enteral protease inhibition adjunctive to intravenous Lactated Ringer's (LR) reperfusion after T/HS. Male Wistar rats underwent midline laparotomy (trauma) and an enteral catheter was inserted orally and positioned post-pyloric for the infusion of vehicle (Golytely®) with or without the serine protease inhibitor gabexate mesilate (GM) (n=8/group). Hemorrhagic shock was induced by blood removal to reduce the mean arterial blood pressure (MAP) to 35-40 mmHg for 90 minutes, before resuscitation with LR. Animals treated with enteral GM required significantly less crystalloid volume to achieve hemodynamic stability and displayed improvements in both blood pressure and autonomic function (via increased baroreflex sensitivity to vasopressors, heightened vascular sympathetic modulation, elevated levels of circulating catecholamines, and increased α1-adrenergic receptor density) compared to untreated (control) shocked animals. Resistance arteries isolated from healthy donor animals and perfused with plasma from untreated T/HS animals revealed impaired vascular response to the α1 adrenergic agonist phenylephrine and decreased reactivity to sodium nitroprusside that was preserved in the GM-treated group. These findings suggest that blockade of serine proteases within the intestinal lumen in non-blood resuscitated experimental T/HS preserves and enhances peripheral sympathetic modulation, improving hemodynamics. Enteral infusion of gabexate mesilate may be a new and promising approach to the management of trauma/hemorrhagic shock.

Combined Treatment with KV Channel Inhibitor 4-Aminopyridine and either γ-Cystathionine Lyase Inhibitor β-Cyanoalanine or Epinephrine Restores Blood Pressure, and Improves Survival in the Wistar Rat Model of Anaphylactic Shock

Simple Summary

Allergic diseases are presenting a constant increase all over the world and caused by such different substances as food, drugs, and pollens. Anaphylactic shock is the more severe complication of allergy which can induce death if the treatment is not administered immediately. Some patients do not respond to the recommended treatment, intra venous or intramuscular epinephrine. The pathophysiology of anaphylactic shock is still under investigation. The mediators released after the activation of mast cells and basophiles act on endothelial cells and smooth muscle cells, inducing the vasodilation responsible for hypotension and shock. Nitric oxide and hydrogen sulphide are both intracellular mediators that induce vasodilation. The role of potassium voltage dependent channels is suspected. We aimed to demonstrate the ability of a blocker of potassium voltage dependent channels, 4-aminopyridine, alone or in combination with inhibitors of cystathionine γ-lyase to restore blood pressure and improve survival in an ovalbumin rat anaphylactic shock model. The blockade of potassium voltage dependent channels alone or combined with inhibitors of cystathionine γ-lyase, dl-propargylglycine, or β-cyanoalanine restored blood pressure and improved survival. These findings suggest possible investigative treatment pathways for research concerning epinephrine-refractory anaphylactic shock in patients.

Abstract

The mechanism of anaphylactic shock (AS) remains incompletely understood. The potassium channel blocker 4-aminopyridine (4-AP), the inhibitors of cystathionine γ-lyase (ICSE), dl-propargylglycine (DPG) or β-cyanoalanine (BCA), and the nitric oxide (NO) synthase produce vasoconstriction and could be an alternative for the treatment of AS. The aim of this study was to demonstrate the ability of L-NAME, ICSE alone or in combination with 4-AP to restore blood pressure (BP) and improve survival in ovalbumin (OVA) rats AS. Experimental groups included non-sensitized Wistar rats (n = 6); AS (n = 6); AS (n = 10 per group) treated i.v. with 4-AP (AS+4-AP), epinephrine (AS+EPI), AS+DPG, AS+BCA, or with L-NAME (AS+L-NAME); or AS treated with drug combinations 4-AP+DPG, 4-AP+BCA, 4-AP+L-NAME, or 4-AP+EPI. AS was induced by i.v. OVA (1 mg). Treatments were administered i.v. one minute after AS induction. Mean arterial BP (MAP), heart rate (HR), and survival were monitored for 60 min. Plasma levels of histamine, prostaglandin E2 (PGE2) and F2 (PGF2α), leukotriene B4 and C4, angiotensin II, vasopressin, oxidative stress markers, pH, HCO3, PaO2, PaCO2, and K+ were measured. OVA induced severe hypotension and all AS rats died. Moreover, 4-AP, 4-AP+EPI, or 4-AP+BCA normalized both MAP and HR and increased survival. All sensitized rats treated with 4-AP alone or with 4-AP+BCA survived. The time-integrated MAP “area under the curve” was significantly higher after combined 4-AP treatment with ICSE. Metabolic acidosis was not rescued and NO, ICSE, and Kv inhibitors differentially alter oxidative stress and plasma levels of anaphylactic mediators. The AS-induced reduction of serum angiotensin II levels was prevented by 4-AP treatment alone or in combination with other drugs. Further, 4-AP treatment combined with EPI or with BCA also increased serum PGF2α, whereas only the 4-AP+EPI combination increased serum LTB4. Serum vasopressin and angiotensin II levels were increased by 4-AP treatment alone or in combination with other drugs. Moreover, 4-AP alone and in combination with inhibition of cystathionine γ-lyase or EPI normalizes BP, increases serum vasoconstrictor levels, and improves survival in the Wistar rat model of AS. These findings suggest possible investigative treatment pathways for research into epinephrine-refractory anaphylactic shock in patients.

Vasoplegic Syndrome after Cardiac Surgery for Infective Endocarditis

Purpose: Post-operative vasoplegic syndrome is a dreaded complication in infective endocarditis (IE). Methods and Results: This retrospective study included 166 consecutive patients referred to cardiac surgery for non-shocked IE. Post-operative vasoplegic syndrome was defined as a persistent hypotension (mean blood pressure < 65 mmHg) refractory to fluid loading and cardiac output restoration. Cardiac surgery was performed 7 (5−12) days after the beginning of antibiotic treatment, 4 (1−9) days after negative blood culture and in 72.3% patients with adapted anti-biotherapy. Timing of cardiac surgery was based on ESC guidelines and operating room availability. Most patients required valve replacement (80%) and cardiopulmonary bypass (CPB) duration was 106 (95−184) min. Multivalvular surgery was performed in 43 patients, 32 had tricuspid valve surgery. Post-operative vasoplegic syndrome was reported in 53/166 patients (31.9%, 95% confidence interval of 24.8−39.0%) of the whole population; only 15.1% (n = 8) of vasoplegic patients had a post-operative documented infection (6 positive blood cultures) and no difference was reported between vasoplegic and non-vasoplegic patients for valve culture and the timing of cardiac surgery. Of the 23 (13.8%) in hospital-deaths, 87.0% (n = 20) occurred in the vasoplegic group and the main causes of death were multiorgan failure (n = 17) and neurological complications (n = 3). Variables independently associated with vasoplegic syndrome were CPB duration (1.82 (1.16−2.88) per tertile) and NTproBNP level (2.11 (1.35−3.30) per tertile). Conclusions: Post-operative vasoplegic syndrome is frequent and is the main cause of death after IE cardiac surgery. Our data suggested that the mechanism of vasoplegic syndrome was more related to inflammatory cardiovascular injury rather than the consequence of ongoing bacteremia.

Glucocorticoids Promote Na+ Excretion in the Renal Epithelia of Heart Failure Rats by Suppressing Transporter Proteins Involved in Acute Sodium Loading

ABSTRACT

Glucocorticoid receptors are essential for normal development and stress responses. Their role in H 2 O and Na + metabolism, especially in chronic heart failure (CHF), is not well defined. In a previous study, we found that glucocorticoids potentiate urination in CHF and promote H 2 O excretion by inhibiting the vasopressin receptor 2 pathway. The present study examines the effect of glucocorticoids on renal Na + excretion and the underlying mechanisms in CHF rats with acute sodium loading. CHF was induced by left coronary artery ligation for 8 weeks. Rats were randomly assigned to 5 groups: control, CHF, dexamethasone (DEX)-administered CHF, DEX-administered CHF treated with RU486 (mifepristone, a glucocorticoid receptor antagonist), and RU486-treated CHF. An acute sodium loading test was performed 6 hours after DEX administration. Blood and urine samples were collected, and hemodynamics were measured. The expression and localization of Na + transporter proteins were determined by immunoblotting and immunohistochemistry. DEX increased the urine volume and urinary sodium and improved cardiac function and the estimated glomerular filtration rate in CHF rats. The upregulation of the epithelial sodium channel β and γ subunits, Na-K-2Cl cotransporter, serum glucocorticoid-regulated kinase 1 (SGK1), and Na + /K + -ATPase in the renal epithelium of CHF rats was downregulated by DEX. These beneficial effects were abolished by RU486. The expression of natriuretic peptide receptor A was opposite that of the above proteins. Glucocorticoids might induce profound natriuresis in CHF rats during acute sodium loading, which is associated with downregulating some Na + transporter proteins in the renal epithelium and improving intrarenal hemodynamics.

Dexmedetomidine to reduce vasopressor resistance in refractory septic shock: Protocol for a double-blind randomized controlled pilot trial (ADRESS Pilot study)

Introduction

Refractory septic shock (RSS) is characterized by high vasopressor requirements, as a consequence of vasopressor resistance, which may be caused or enhanced by sympathetic hyperactivation. Experimental models and clinical trials show a reduction in vasopressor requirements and improved microcirculation compared to conventional sedation. Dexmedetomidine did not reduce mortality in clinical trials, but few septic shock patients were enrolled. This pilot trial aims to evaluate vasopressor re-sensitization with dexmedetomidine and assess the effect size, in order to design a larger trial.

Methods

This is an investigator-initiated, multicenter, randomized, double-blind, placebo-controlled trial, comparing dexmedetomidine versus placebo in RSS patients with norepinephrine dose ≥0.5μg/kg/min. The primary outcome is blood pressure response to phenylephrine challenge, 6 hours after completion of a first challenge, after study treatment initiation. Secondary outcomes include feasibility and safety outcomes (bradycardia), mortality, vasopressor requirements, heart rate variability, plasma and urine catecholamines levels. The sample size is estimated at 32 patients to show a 20% improvement in blood pressure response to phenylephrine. Randomization (1:1) will be stratified by center, sedation type and presence of liver cirrhosis. Blood pressure and ECG will be continuously recorded for the first 24 h, enabling high-quality data collection for the primary and secondary endpoints. The study was approved by the ethics committee “Sud-Est VI” (2019-000726-22) and patients will be included after informed consent.

Discussion

The present study will be the first randomized trial to specifically address the hemodynamic effects of dexmedetomidine in patients with septic shock. We implement a high-quality process for data acquisition and recording in the first 24 h, ensuring maximal quality for the evaluation of both efficacy and safety outcomes, as well as transparency of results. The results of the study will be used to elaborate a full-scale randomized controlled trial with mortality as primary outcome in RSS patients.

Trial registration

Registered with ClinicalTrials.gov (NCT03953677). Registered 16 May 2019, https://clinicaltrials.gov/ct2/show/NCT03953677.

The pharmacotherapeutic options in patients with catecholamine-resistant vasodilatory shock

INTRODUCTION

Septic and vasoplegic shock are common types of vasodilatory shock (VS) with high mortality. After fluid resuscitation and the use of catecholamine-mediated vasopressors (CMV), vasopressin, angiotensin II, methylene blue (MB) and hydroxocobalamin can be added to maintain blood pressure.

AREAS COVERED

VS treatment utilizes a phased approach with secondary vasopressors added to vasopressor agents to maintain an acceptable mean arterial pressure (MAP). This review covers additional vasopressors and adjunctive therapies used when fluid and catecholamine-mediated vasopressors fail to maintain target MAP.

EXPERT OPINION

Evidence supporting additional vasopressor agents in catecholamine resistant VS is limited to case reports, series, and a few randomized control trials (RCTs) to guide recommendations. Vasopressin is the most common agent added next when MAPs are not adequately supported with CMV. VS patients failing fluids and vasopressors with cardiomyopathy may have cardiotonic agents such as dobutamine or milrinone added before or after vasopressin. Angiotensin II, another class of vasopressor is used in VS to maintain adequate MAP. MB and/or hydoxocobalamin, vitamin C, thiamine and corticosteroids are adjunctive therapies used in refractory VS. More RCTs are needed to confirm the utility of these drugs, at what doses, which combinations and in what order they should be given.

Effect of preoperative renin-angiotensin system blockade on vasoplegia after cardiac surgery: A systematic review with meta-analysis

BACKGROUND

Vasoplegia is a common complication of cardiac surgery but its causal relationship with preoperative use of renin angiotensin system (RAS) blockers [angiotensin converting enzyme inhibitors (ACEIs) and angiotensin receptor blockers (ARB)] is still debated.

AIM

To update and summarize data on the effect of preoperative use of RAS blockers on incident vasoplegia.

METHODS

All published studies from MEDLINE, EMBASE, and Web of Science providing relevant data through January 13, 2021 were identified. A random-effects meta-analysis method was used to pool estimates, and post-cardiac surgery shock was differentiated from vasoplegia.

RESULTS

Ten studies reporting on a pooled population of 15672 patients (none looking at ARBs exclusively) were included in the meta-analysis. All were case-control studies. Use of ACEIs was associated with an increased risk of vasoplegia [pooled adjusted odds ratio (Aor) of 2.06, 95%CI: 1.45-2.93] and increased inotropic/vasopressor support requirement (pooled aOR 1.19, 95%CI: 1.10-1.29). Post-cardiac surgery shock was increased in the presence of left ventricular dysfunction (pooled aOR 2.32, 95%CI: 1.60-3.36; I² 49%) but not increased by the use of beta blockers (pooled aOR 0.78, 95%CI: 0.36-1.69; I² 77%). Two randomized control trials (RCTs), not eligible for the meta-analysis, did not show an association between continuation of RAS blockers and vasoplegia.

CONCLUSION

Preoperative continuation of ACEIs is associated with an increased need for inotropic support postoperatively and with an increased risk of vasoplegia in observational studies but not in RCTs. The absence of a consensus definition of vasoplegia should lead to the use of perioperative cardiovascular monitoring when designing RCTs to better understand this discrepancy.

Pathophysiological, Cellular, and Molecular Events of the Vascular System in Anaphylaxis

Anaphylaxis is a systemic hypersensitivity reaction that can be life threatening. Mechanistically, it results from the immune activation and release of a variety of mediators that give rise to the signs and symptoms of this pathological event. For years, most of the research in anaphylaxis has focused on the contribution of the immune component. However, approaches that shed light on the participation of other cellular and molecular agents are necessary. Among them, the vascular niche receives the various signals (e.g., histamine) that elicit the range of anaphylactic events. Cardiovascular manifestations such as increased vascular permeability, vasodilation, hypotension, vasoconstriction, and cardiac alterations are crucial in the pathophysiology of anaphylaxis and are highly involved to the development of the most severe cases. Specifically, the endothelium, vascular smooth muscle cells, and their molecular signaling outcomes play an essential role downstream of the immune reaction. Therefore, in this review, we synthesized the vascular changes observed during anaphylaxis as well as its cellular and molecular components. As the risk of anaphylaxis exists both in clinical procedures and in routine life, increasing our knowledge of the vascular physiology and their molecular mechanism will enable us to improve the clinical management and how to treat or prevent anaphylaxis.

Key Message

Anaphylaxis, the most severe allergic reaction, involves a variety of immune and non-immune molecular signals that give rise to its pathophysiological manifestations. Importantly, the vascular system is engaged in processes relevant to anaphylactic events such as increased vascular permeability, vasodilation, hypotension, vasoconstriction, and decreased cardiac output. The novelty of this review focuses on the fact that new studies will greatly improve the understanding of anaphylaxis when viewed from a vascular molecular angle and specifically from the endothelium. This knowledge will improve therapeutic options to treat or prevent anaphylaxis.

Gene Expression Scoring of Immune Activity Levels for Precision Use of Hydrocortisone in Vasodilatory Shock

PURPOSE

Among patients with vasodilatory shock, gene expression scores may identify different immune states. We aimed to test whether such scores are robust in identifying patients' immune state and predicting response to hydrocortisone treatment in vasodilatory shock.

MATERIALS AND METHODS

We selected genes to generate continuous scores to define previously established subclasses of sepsis. We used these scores to identify a patient's immune state. We evaluated the potential for these states to assess the differential effect of hydrocortisone in two randomized clinical trials of hydrocortisone versus placebo in vasodilatory shock.

RESULTS

We initially identified genes associated with immune-adaptive, immune-innate, immune-coagulant functions. From these genes, 15 were most relevant to generate expression scores related to each of the functions. These scores were used to identify patients as immune-adaptive prevalent (IA-P) and immune-innate prevalent (IN-P). In IA-P patients, hydrocortisone therapy increased 28-day mortality in both trials (43.3% vs 14.7%, P = 0.028) and (57.1% vs 0.0%, P = 0.99). In IN-P patients, this effect was numerically reversed.

CONCLUSIONS

Gene expression scores identified the immune state of vasodilatory shock patients, one of which (IA-P) identified those who may be harmed by hydrocortisone. Gene expression scores may help advance the field of personalized medicine.

Biomarkers Predicting Tissue Pharmacokinetics of Antimicrobials in Sepsis: A Review

The pathophysiology of sepsis alters drug pharmacokinetics, resulting in inadequate drug exposure and target-site concentration. Suboptimal exposure leads to treatment failure and the development of antimicrobial resistance. Therefore, we seek to optimize antimicrobial therapy in sepsis by selecting the right drug and the correct dosage. A prerequisite for achieving this goal is characterization and understanding of the mechanisms of pharmacokinetic alterations. However, most infections take place not in blood but in different body compartments. Since tissue pharmacokinetic assessment is not feasible in daily practice, we need to tailor antibiotic treatment according to the specific patient’s pathophysiological processes. The complex pathophysiology of sepsis and the ineffectiveness of current targeted therapies suggest that treatments guided by biomarkers predicting target-site concentration could provide a new therapeutic strategy. Inflammation, endothelial and coagulation activation markers, and blood flow parameters might be indicators of impaired tissue distribution. Moreover, hepatic and renal dysfunction biomarkers can predict not only drug metabolism and clearance but also drug distribution. Identification of the right biomarkers can direct drug dosing and provide timely feedback on its effectiveness. Therefore, this might decrease antibiotic resistance and the mortality of critically ill patients. This article fills the literature gap by characterizing patient biomarkers that might be used to predict unbound plasma-to-tissue drug distribution in critically ill patients. Although all biomarkers must be clinically evaluated with the ultimate goal of combining them in a clinically feasible scoring system, we support the concept that the appropriate biomarkers could be used to direct targeted antibiotic dosing.

Cutoff Values of Hemodynamic Parameters in Pediatric Refractory Septic Shock

Background: Refractory septic shock can cause severe morbidities and mortalities in children. Resuscitation based on hemodynamics is important in children with critical illness. Thus, this study aimed to identify the hemodynamics of refractory septic shock associated with poor prognosis at an early stage to allow for timely interventions. Methods: We evaluated children with refractory septic shock admitted to a pediatric intensive care unit (PICU) and monitored their hemodynamics using a pulse index continuous cardiac output (PiCCO) system. The serial cardiac index (CI), systemic vascular resistance index (SVRI), and vasoactive−inotropic score (VIS) were recorded during the first 72 h after PICU admission. Results: Thirty-three children with refractory septic shock were enrolled. The SVRI and VIS were both associated with fatality from septic shock. The non-survivors had lower serial SVRI and higher VIS (both p < 0.05). Based on the area under the ROC curve, the SVRI was the predictor during the early resuscitative stage (first 36 h) in pediatric refractory septic shock. Conclusions: Both SVRI and VIS are predictors of mortality in children with refractory septic shock, and the SVRI is the powerful predictor of mortality in the early resuscitative stage. A low serial SVRI may allow for the early awareness of disease severity and strategies for adjusting vasoactive−inotropic agents to increase the SVRI.

Early Use of Methylene Blue in Vasoplegic Syndrome: A 10-Year Propensity Score-Matched Cohort Study

Background: Vasoplegic syndrome is associated with increased morbidity and mortality in patients undergoing cardiac surgery. This retrospective, single-center study aimed to evaluate the effect of early use of methylene blue (MB) on hemodynamics after an intraoperative diagnosis of vasoplegic syndrome (VS). Methods: Over a 10-year period, all patients diagnosed with intraoperative VS (hypotension despite treatment with norepinephrine ≥0.3 μg/kg/min and vasopressin ≥1 IE/h) while undergoing heart surgery and cardiopulmonary bypass were identified, and their data were examined. The intervention group received MB (2 mg/kg intravenous) within 15 min after the diagnosis of vasoplegia, while the control group received standard therapy. The two groups were matched using propensity scores. Results: Of the 1022 patients identified with VS, 221 received MB intraoperatively, and among them, 60 patients received MB within 15 min after the diagnosis of VS. After early MB application, mean arterial pressure was significantly higher, and vasopressor support was significantly lower within the first hour (p = 0.015) after the diagnosis of vasoplegia, resulting in a lower cumulative amount of norepinephrine (p = 0.018) and vasopressin (p = 0.003). The intraoperative need of fresh frozen plasma in the intervention group was lower compared to the control group (p = 0.015). Additionally, the intervention group had higher creatinine values in the first three postoperative days (p = 0.036) without changes in dialysis incidence. The 90-day survival did not differ significantly (p = 0.270). Conclusion: Our results indicate the additive effects of MB use during VS compared to standard vasopressor therapy only. Early MB administration for VS may significantly improve the patients’ hemodynamics with minor side effects.

Mortality Risk Factors for Patients With Sepsis-Induced Blood Pressure Drop: A Single-Center Retrospective Study

Introduction: Sepsis is a life-threatening illness caused by the body's response to uncontrolled infection. Different studies have been conducted to identify risk factors associated with the diagnosis of sepsis and mortality, but there has been considerably less focus on mortality due to sepsis-induced blood pressure. The current study was conducted to determine the incidence of mortality within 30 days among patients with sepsis-induced blood pressure drop and its risk factors.

Methodology: It was a retrospective study conducted at the Pakistan Navy Station (PNS) Shifa Hospital, Karachi, Pakistan. Data of all patients aged 18 years or more who visited PNS Shifa Hospital and were diagnosed with sepsis and blood pressure reduction from November 2019 to October 2021 were extracted from Hospital Management Information System (HMIS) and retrospectively analyzed

Results: All variables significantly associated with 30-days mortality in multivariable logistic regression analysis, including disturbance of consciousness, cardiac insufficiency, respiratory failure, diabetes mellitus, creatinine level, and aspartate aminotransferase (AST) level, were risk factors for mortality in patients with the sepsis-induced drop in blood pressure (p-value<0.05).

Conclusion: Identifying these risk factors is important as it will help clinicians identify patients who are at high risk of mortality at an early stage. Through early identification, interventions can be done to reduce the incidence of in-hospital mortality among sepsis patients.

Vasoplegic Syndrome Post-cardiopulmonary Bypass in a Renal Transplant Patient: The Brain Is Not the Index Organ

Vasoplegia syndrome (VS) is seen in cardiac surgery post-cardiopulmonary bypass (CPB) and defined by increasing requirements for more than one vasoactive agent to which the patient's response is reduced. It is also associated with normal or high cardiac output (CO). Prolonged CPB time is the second commonest precipitating factor. Here, we describe a young adult, with good right ventricular (RV) and left ventricular (LV) function, who previously was a renal transplant recipient with a functioning kidney who developed VS and shock after CPB to replace the mitral and aortic valves. During the first two hours of CPB, his mean arterial blood pressure (MAP) was never lower than 50 mmHg. His brain regional cerebral oxygen saturation (rSO₂) remained above baseline, and his body temperature was kept at 33°C. Urine output was constant at 40 ml/hr. He came off CPB requiring two inotropes and two vasoconstrictors. Even so, his systolic blood pressure was low, and his pulse pressure narrows. He was then started on methylene blue which improved his MAP. On arrival to the intensive care unit (ICU), he immediately required continuous veno-veno haemodialysis (CVVHD) and developed acute liver failure. At 16 hours, he showed a clinically fair neurological recovery. Forty-eight hours post-surgery, he suffered multiorgan failure and developed an intractable arrhythmia and died. The unusual components were as follows: he was normally responsive to phenylephrine during CPB; despite normal rSO₂ and a clinically neurological recovery, he suffered multiorgan failure; and his serial high-sensitivity (HS) troponin I levels never fell below 500,000 pg/ml (normal <14 pg/ml).