Cardiogenic Shock: Failure of Oxygen Delivery and Oxygen Utilization

Cardiogenic shock trajectories: is the Society for Cardiovascular Angiography and Interventions definition the right one?

PURPOSE OF REVIEW

We review the current Society for Cardiovascular Angiography and Interventions (SCAI) cardiogenic shock classification system and consider alternatives or iterations that may enhance our current descriptions of cardiogenic shock trajectory.

RECENT FINDINGS

Several studies have identified the potential prognostic value of serial SCAI stage re-assessment, usually within the first 24 h of shock onset, to predict deterioration and clinical outcomes across shock causes. In parallel, numerous registry-based analyses support the utility of a more precise assessment of the macrocirculation and microcirculation, leveraging invasive haemodynamics, imaging and additional laboratory and clinical markers. The emergence of machine learning and artificial intelligence capabilities offers the opportunity to integrate multimodal data into high fidelity, real-time metrics to more precisely define trajectory and inform our therapeutic decision making.

SUMMARY

Whilst the SCAI staging system remains a pivotal tool in cardiogenic shock assessment, communication and reassessment, it is vital that the sophistication with which we measure and assess shock trajectory evolves in parallel our understanding of the complexity and variability of clinical course and clinical outcomes.

A mathematical model of tissue axial and radial diffusion in the microvasculature for intravascular microscopy and phosphorescence quenching data

This study aims to extend earlier Krogh Cylinder Models of an oxygen profile by considering axial diffusion and analytically solving Fick's Law Partial Differential Equation with novel boundary conditions via the separation of variables. We next prospectively collected a total of 20 animals, which were randomly assigned to receive either fresh or two-week-old stored red blood cell (RBC) transfusions and PQM oxygen data were measured acutely (90 min) or chronically (24 h). Transfusion effects were evaluated in vivo using intravital microscopy of the dorsal skinfold window chamber in Golden Syrian Hamsters. Hamsters were initially hemorrhaged by 50% of total blood volume and resuscitated 1-h post hemorrhage. PQM data were subsequently collected and fit the derived 2D Krogh cylinder model. Systemic hemodynamics (mean arterial pressure, heart rate) were similar in both pre and post-transfusion with either stored or fresh cells. Transfusion with stored cells was found to impair axial and radial oxygen gradients as quantified by our model and consistent with previous studies. Specifically, we observed a statistically significant decrease in the arteriolar tissue radial oxygen gradient after transfusion with stored RBCs at 24 h compared with fresh RBCs (0.33 ± 0.17 mmHg μ m-1 vs, 0.14 ± 0.12 mmHg μ m-1; p = 0.0280). We also observed a deficit in the arteriolar tissue oxygen gradient (0.03 ± 0.01 mmHg μ m-1 fresh vs. 0.018 ± 0.007 mmHg μ m-1 stored; p = 0.0185). We successfully derived and validated an analytical 2D Krogh cylinder model in an animal model of microhemodynamic oxygen diffusion aberration secondary to storage lesions.

Management of cardiogenic shock: a narrative review

Cardiogenic shock (CS) is characterized by low cardiac output and sustained tissue hypoperfusion that may result in end-organ dysfunction and death. CS is associated with high short-term mortality, and its management remains challenging despite recent advances in therapeutic options. Timely diagnosis and multidisciplinary team-based management have demonstrated favourable effects on outcomes. We aimed to review evidence-based practices for managing patients with ischemic and non-ischemic CS, detailing the multi-organ supports needed in this critically ill patient population.

Systemic Venous Congestion Reviewed

Accurate determination of intravascular volume status is challenging in acutely ill patients. Favorable patient outcome is vital to correctly identify intravascular volume depletion and avoid systemic venous congestion. Most of the conventional means of hemodynamic monitoring in the acute healthcare setting are geared toward addressing the cardiac output and maintaining an optimum mean arterial pressure. While assessing and maintaining cardiac output in an acutely ill patient is very important, a venous congestion cascade is often overlooked, which can negatively affect the intraabdominal end organs. The prospect of using point-of-care ultrasound (POCUS) to determine systemic venous congestion could be a potentially handy tool for clinicians. Venous excess ultrasound score (VExUS) has also been utilized by clinicians as a semi-quantitative assessment tool to assess fluid status. This review aims to discuss the potential role of POCUS and VExUS scores in determining systemic venous congestion through a narrative review of recently published literature.

Blood redistribution preferentially protects vital organs under hypoxic stress in Pelteobagrus vachelli

Blood redistribution occurs in mammals under hypoxia but has not been reported in fish. This study investigated the tissue damage, hypoxia-inducible factor (HIF) activation level, and blood flow changes in the brain, liver, and muscle of Pelteobagrus vachelli during the hypoxia process for normoxia-hypoxia-asphyxia. The results showed that P. vachelli has tissue specificity in response to hypoxic stress. Cerebral blood flow increased with less damage than in the liver and muscle, suggesting that P. vachelli may also have a blood redistribution mechanism in response to hypoxia. It is worth noting that severe hypoxia can lead to a sudden increase in the degree of brain tissue damage. In addition, higher dissolved oxygen levels activate HIF and may have contributed to the reduced damage observed in the brain. This study provides basic data for investigating hypoxic stress in fish.

Prevalence and Predictors of Cardiogenic Shock in Intermediate-Risk Pulmonary Embolism: Insights From the FLASH Registry

BACKGROUND

Patients with acute pulmonary embolism (PE) and hypotension (high-risk PE) have high mortality. Cardiogenic shock can also occur in nonhypotensive or normotensive patients (intermediate-risk PE) but is less well characterized.

OBJECTIVES

The authors sought to evaluate the prevalence and predictors of normotensive shock in intermediate-risk PE.

METHODS

Intermediate-risk PE patients in the FLASH (FlowTriever All-Comer Registry for Patient Safety and Hemodynamics) registry undergoing mechanical thrombectomy with the FlowTriever System (Inari Medical) were included. The prevalence of normotensive shock (systolic blood pressure ≥90 mm Hg but cardiac index ≤2.2 L/min/m²) was assessed. A composite shock score consisting of markers of right ventricular function and ischemia (elevated troponin, elevated B-type natriuretic peptide, moderately/severely reduced right ventricular function), central thrombus burden (saddle PE), potential additional embolization (concomitant deep vein thrombosis), and cardiovascular compensation (tachycardia) was prespecified and assessed for its ability to identify normotensive shock patients.

RESULTS

Over one-third of intermediate-risk PE patients in FLASH (131/384, 34.1%) were in normotensive shock. The normotensive shock prevalence was 0% in patients with a composite shock score of 0 and 58.3% in those with a score of 6 (highest score). A score of 6 was a significant predictor of normotensive shock (odds ratio: 5.84; 95% CI: 2.00-17.04). Patients showed significant on-table improvements in hemodynamics post-thrombectomy, including normalization of the cardiac index in 30.5% of normotensive shock patients. Right ventricular size, function, dyspnea, and quality of life significantly improved at the 30-day follow-up.

CONCLUSIONS

Although hemodynamically stable, over one-third of intermediate-risk FLASH patients were in normotensive shock with a depressed cardiac index. A composite shock score effectively further risk stratified these patients. Mechanical thrombectomy improved hemodynamics and functional outcomes at the 30-day follow-up.

Stroke Volume and Arterial Pressure Fluid Responsiveness in Patients With Elevated Stroke Volume Variation Undergoing Major Vascular Surgery: A Prospective Intervention Study

OBJECTIVES

The identification of potential hemodynamic indicators to increase the predictive power of stroke-volume variation (SVV) for mean arterial pressure (MAP) and stroke volume (SV) fluid responsiveness.

DESIGN

A prospective intervention study.

SETTING

At a single-center university hospital.

PARTICIPANTS

Nineteen patients during major vascular surgery with 125 fluid interventions.

INTERVENTIONS

When SVV ≥13% occurred for >30 seconds, 250 mL of Ringer's lactate were given within 2 minutes.

MEASUREMENTS AND MAIN RESULTS

Hemodynamic variables, such as pulse-pressure variation (PPV) and dynamic arterial elastance (Edyn), were measured by pulse power-wave analysis. The outcomes were MAP and SV responsiveness, defined as an increase of at least 10% of MAP and SV within 5 minutes of the fluid intervention. Of the fluid interventions, 48% were MAP-responsive, and 66% were SV-responsive. The addition of PPV and Edyn cut-off values to the SVV cut-off decreased sensitivity from 1-to-0.66 to-0.82, and concomitantly increased specificity from 0-to- 0.65-to-0.93 for the prediction of MAP and SV responsiveness in the authors' study setting. The areas under the receiver operating characteristic curves of PPV and Edyn for the prediction of MAP responsiveness were 0.79 and 0.75, respectively. The areas under the receiver operating characteristic curves for PPV and Edyn to predict SV responsiveness were 0.85 and 0.77, respectively.

CONCLUSIONS

The PPV and Edyn showed good accuracy for the prediction of MAP and SV responsiveness in patients with elevated SVV during vascular surgery. Either PPV or Edyn may be used in conjunction with SVV to better predict MAP and SV fluid responsiveness in patients undergoing vascular surgery.

Pharmacological treatment of cardiogenic shock - A state of the art review

Cardiogenic shock is a clinical syndrome of impaired tissue perfusion caused by primary cardiac dysfunction and inadequate cardiac output. It represents one of the most lethal clinical conditions in intensive care medicine with mortality >40%. Management of different clinical presentations of cardiogenic shock includes guidance of cardiac preload, afterload, heart rate and contractility by differential pharmacological modulation of volume, systemic and pulmonary vascular resistance and cardiac output besides reversing the triggering cause. Data from large registries and randomized controlled trials on optimal diagnostic guidance as well as choice of pharmacological agents has accrued significantly in recent years. This state-of-the-art review summarizes the basic concepts of cardiogenic shock, the diagnostic work-up and currently available evidence and guideline recommendations on pharmacological treatment of cardiogenic shock.

Phenotyping and Hemodynamic Assessment in Cardiogenic Shock: From Physiology to Clinical Application

There is growing interest in invasive hemodynamic assessment in cardiogenic shock, primarily due to the widespread adoption of mechanical circulatory support (MCS). Invasive hemodynamic assessment is central to two aspects of cardiogenic shock management: (1) the phenotyping of cardiogenic shock, and (2) the assessment of response to therapy. Phenotyping of cardiogenic shock serves to guide timely therapeutic intervention, and the assessment of hemodynamic response to therapy directs the escalation or de-escalation of therapy, including MCS. This review aims to discuss these two aspects of hemodynamic assessment in cardiogenic shock. Firstly, the physiologic underpinnings of a phenotyping schema, and the implication of the cardiogenic shock phenotype on the MCS strategy in cardiogenic shock will be discussed. Secondly, the concept of cardiac power output and 'effective' oxygen delivery will be discussed in relation to hemodynamic response to therapy in cardiogenic shock.

Inotropic support in cardiogenic shock: who leads the battle, milrinone or dobutamine?

Cardiovascular diseases remain the leading cause of death globally, with acute myocardial infarction being one of the most frequent. One of the complications that can occur after a myocardial infarction is cardiogenic shock. At present, the evidence on the use of inotropic agents for the management of this complication is scarce, and only a few trials have evaluated the efficacy-adverse effects relationship of some agents. Milrinone and Dobutamine are some of the most frequently mentioned drugs that have been studied recently. However, there are still no data that affirm with certainty the supremacy of one over the other. The aim of this review is to synthesize evidence on basic and practical aspects of these agents, allowing us to conclude which might be more useful in current clinical practice, based on the emerging literature.

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Studies suggest that Milrinone has a higher safety and efficacy profile over Dobutamine.

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The evidence on the advantages of using Milrinone vs. Dobutamine is heterogeneous.

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Additional factors need to be considered to reduce the risk of adverse events.

The Intensivist's Perspective of Shock, Volume Management, and Hemodynamic Monitoring

One of the primary reasons for intensive care admission is shock. Identifying the underlying cause of shock (hypovolemic, distributive, cardiogenic, and obstructive) may lead to entirely different clinical pathways for management. Among patients with hypovolemic and distributive shock, fluid therapy is one of the leading management strategies. Although an appropriate amount of fluid administration might save a patient's life, inadequate (or excessive) fluid use could lead to more complications, including organ failure and mortality due to either hypovolemia or volume overload. Currently, intensivists have access to a wide variety of information sources and tools to monitor the underlying hemodynamic status, including medical history, physical examination, and specific hemodynamic monitoring devices. Although appropriate and timely assessment and interpretation of this information can promote adequate fluid resuscitation, misinterpretation of these data can also lead to additional mortality and morbidity. This article provides a narrative review of the most commonly used hemodynamic monitoring approaches to assessing fluid responsiveness and fluid tolerance. In addition, we describe the benefits and disadvantages of these tools.

Myocardial oedema: pathophysiological basis and implications for the failing heart

Myocardial fluid homeostasis relies on a complex interplay between microvascular filtration, interstitial hydration, cardiomyocyte water uptake and lymphatic removal. Dysregulation of one or more of these mechanisms may result in myocardial oedema. Interstitial and intracellular fluid accumulation disrupts myocardial architecture, intercellular communication, and metabolic pathways, decreasing contractility and increasing myocardial stiffness. The widespread use of cardiac magnetic resonance enabled the identification of myocardial oedema as a clinically relevant imaging finding with prognostic implications in several types of heart failure. Furthermore, growing experimental evidence has contributed to a better understanding of the physical and molecular interactions in the microvascular barrier, myocardial interstitium and lymphatics and how they might be disrupted in heart failure. In this review, we summarize current knowledge on the factors controlling myocardial water balance in the healthy and failing heart and pinpoint the new potential therapeutic avenues.

Efficacy of Veno-Arterial Extracorporeal Life Support in Adult Patients with Refractory Cardiogenic Shock

Background

This study aimed to describe the efficacy of veno-arterial extracorporeal life support (VA-ECLS) through early lactate clearance and pH restoration and assess the potential association with 30-day survival following hospital discharge.

Methods

Data of patients receiving VA-ECLS for at least 24 h were retrospectively compiled. Blood lactate levels, liver enzymes, and kidney parameters prior to VA-ECLS initiation and at 2, 8, 14, 20, and 26 h of support had been recorded as part of clinical care. The primary outcome was 30-day survival.

Results

Of 77 patients who underwent VA-ECLS for refractory cardiogenic shock, 44.2% survived. For all non-survivors, ECLS was initiated after eight hours (p = .008). Blood pH was significantly higher in survivors compared to non-survivors at all time points except for pre-ECLS. Lactate levels were significantly lower in survivors (median range 1.95-4.70 vs 2.90-6.70 mmol/L for survivors vs non-survivors, respectively). Univariate and multivariate analyses indicated that blood pH at 24 h (OR 0.045, 95% CI: 0.005-0.448 for pH <7.35, p = .045) and lactate concentration pre-ECLS (OR 0.743, 95% CI: 0.590-0.936, p = .012) were reliable predictors for 30-day survival. Further, ischemic cardiogenic shock as ECLS indication showed 36.2% less lactate clearance compared to patients with other indications such as arrhythmia, postcardiotomy, and ECPR.

Conclusion

ECLS showed to be an effective treatment in reducing blood lactate levels in patients suffering from refractory cardiogenic shock in which the outcome is influenced by the initial lactate level and pH in the early phase of the intervention.

Complicating Acute Myocardial Infarction. Current Status and Unresolved Targets for Subsequent Research

Mechanical reperfusion with primary angioplasty, as the treatment of choice in acute myocardial infarction (MI), is associated not only with a high percentage of full epicardial and tissue reperfusion but also with a very good immediate and long-term clinical outcome. However, the Achilles heel of MI treatment is its ensemble of complications, such as cardiogenic shock due to severe systolic and/or diastolic dysfunction or MI mechanical complications, including perforation of the left ventricular free wall, papillary muscle rupture with acute mitral regurgitation and ventricular septal rupture. They are associated with an increased or, sometimes, with an extremely high mortality rate, determining the overall mortality in an MI patient population. In this review we summarize the mechanisms of MI complications, current therapeutic management and alternative directions for overcoming their devastating consequences. Moreover, we have sought to indicate gaps in the evidence on current treatments as the potential targets for further clinical research. From the perspective of mortality trends that are not improving, the forthcoming therapeutic management of complicated MI will require an individualized and novel approach based on their thorough pathobiology.

Elevated Arterial-Central Venous Carbon Dioxide Partial Pressure Difference Indicates Poor Prognosis in the Early Postoperative Period of Open Heart Surgery in Infants with Congenital Heart Disease

BACKGROUND

Elevated arterial-central venous carbon dioxide partial pressure difference (AVCO₂) may be an important marker to predict tissue and organ hypoperfusion in adults. We analyzed the hemodynamic data of infants with congenital heart disease who underwent corrective repair with cardiopulmonary bypass (CPB) to identify whether AVCO₂ has clinical significance in early postoperative tissue hypoperfusion, occurrence of complications, and clinical outcomes.

METHODS

Infants with clinical conditions of hypoperfusion, without volume responsiveness and with ineffective initial treatment, within 3 h of cardiac surgery were enrolled in this study. A pulse contour cardiac output catheter was used to monitor the cardiac index (CI). Eight measurements of arterial blood gas and central venous blood gas were taken within 42 h after surgery. Clinical data of all patients were recorded.

RESULTS

A total of 69 children were enrolled in this study. Arteriovenous oxygen difference, AVCO₂, lactic acid level, and vasoactive inotropic score in the hypoperfusion group (oxygen supply/oxygen consumption ratio [DO₂/VO₂] of ≤ 2) were significantly higher than those in the non-hypoperfusion group (DO₂/VO₂ > 2), while the CI in the hypoperfusion group was significantly lower than that in the non-hypoperfusion group. The cutoff value of AVCO₂ to predict DO₂/VO₂ ≤ 2 was 12.3 within 42 h of surgery with area under the curve of 0.84. High AVCO₂ is more likely to be associated with some complications and prolonged mechanical ventilation and length of stay in the intensive care unit.

CONCLUSION

Elevated AVCO₂ within 42 h of CPB in infants is associated with tissue and organ hypoperfusion and incidence of complications. Persistent or repeated increase in AVCO₂ indicates poor prognosis.

CD14 Involvement in Third-degree Skin Burn-induced Myocardial Injury via the MAPK Signaling Pathway

This study investigated the potential genes and related pathways in burn-induced myocardial injury. Rat myocardial injury induced by third-degree burn and the histopathological structures, apoptosis, and cardiac injury markers were then identified using hematoxylin & eosin staining, terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling staining, and enzyme-linked immunosorbent assay. Next, differentially expressed mRNAs were screened through next-generation sequencing (NGS), followed by functional annotation and key gene validation through quantitative reverse transcription-polymerase chain reaction. Subsequently, CD14 was screened out, and small interfering RNAs against CD14 were transfected to H9C2 cells to further verify the role of CD14 in burn-induced injury. The results showed that third-degree burn could markedly damage the structure of myocardial tissue, induce the apoptosis of myocardial cells, and increase the levels of myocardial injury-related markers, suggesting that burns could induce myocardial injury in rats. Besides, NGS data discovered that third-degree burn could result in 416 differentially upregulated mRNAs and 285 differentially downregulated mRNAs in myocardial tissue. It was also disclosed that differentially expressed mRNAs were mainly enriched in the phosphatidylinositol 3-kinase/Akt, mitogen-activated protein kinase (MAPK), and tumor necrosis factor signaling pathways. Furthermore, cell viability was significantly decreased in H9C2 cells treated with 10% rat burn serum. CD14 was significantly differentially expressed and screened out for further studies. Treatment with burn serum can significantly upregulate the phosphorylation level of extracellular signal-regulated kinase, p38, and c-Jun N-terminal kinase and the expression of cleaved caspase-3 and downregulate the expression of Bcl2 when compared with those in negative control of small interfering RNA transfected H9C2 cells, whereas interfering with CD14 expression reversed the effects of burn serum. The study demonstrated that burn serum treatment could activate the MAPK signaling pathway to promote cell apoptosis, and it can be reversed by interfering with the expression of CD14.

Different Expressions of HIF-1α and Metabolism in Brain and Major Visceral Organs of Acute Hypoxic Mice

Hypoxia is associated with clinical diseases. Extreme hypoxia leads to multiple organs failure. However, the different effects of hypoxia on brain and visceral organs still need to be clarified, and moreover, characteristics in vulnerable organs suffering from hypoxia remain elusive. In the present study, we first aimed to figure out the hypoxic sensitivity of organs. Adult male mice were exposed to 6% O2 or 8% O2 for 6 h. Control mice were raised under normoxic conditions. In vivo and in vitro imaging of anti-HIF-1α-NMs-cy5.5 nanocomposites showed that the expression level of hypoxia-inducible factor (HIF-1α) was the highest in the liver, followed by kidney and brain. HIF-1α was detected in the hepatocytes of liver, distal convoluted tubules of kidney and neurons of cerebral cortex. The liver, kidney and brain showed distinct metabolic profiles but an identical change in glutamate. Compared with kidney and brain, the liver had more characteristic metabolites and more disturbed metabolic pathways related to glutaminolysis and glycolysis. The level of O-phosphocholine, GTP, NAD and aspartate were upregulated in hypoxic mice brain, which displayed significant positive correlations with the locomotor activity in control mice, but not in hypoxic mice with impaired locomotor activities. Taken together, the liver, kidney and brain are the three main organs of the body that are strongly respond to acute hypoxia, and the liver exhibited the highest hypoxic sensitivity. The metabolic disorders appear to underlie the physiological function changes.

Myocardial Edema: an Overlooked Mechanism of Septic Cardiomyopathy?

Septic cardiomyopathy is an increasingly relevant topic in clinical management of septic shock. However, pathophysiological mechanisms and long-term consequences of sepsis-induced myocardial injury are still poorly understood. Herein, new clinical and histological evidence is provided suggesting an association of myocardial edema formation with tissue injury and subsequent remodeling in septic shock patients. This preliminary data supports myocardial edema as a potentially relevant and largely unexplored mechanism of human septic cardiomyopathy.

Anemia as a Risk Factor for Organ Dysfunctions in Patients Operated on Heart Valves

Aim      To study the effects of pre- and postoperative anemia on the risk and the structure of internal organ dysfunction in patients undergoing surgery for acquired heart diseases (AHD).Material and methods  This was a retrospective cohort study including 610 primarily operated patients with AHD. A comparative analysis of the incidence and the structure of internal organ dysfunction was performed, and the likelihood of intraoperative hemotransfusion was determined for patients with preoperative anemia (Hb &lt;130 g/l) and without it. The incidence and the nature of internal organ damage were compared in patients with postoperative Hb &lt; 90 g/l and 90-130 g/l.Results The presence of postoperative anemia detected in 45 % of patients at two days after the surgery 6-fold increased the risk of acute heart failure (odds ratio [OR], 5.75; 95 % confidence interval [CI], 1.23-26.84; р=0.016), 4-fold increased the risk of multiorgan failure (MOF) (OR, 4.2; 95 % CI, 1.16-15.64; р=0.03), and 5-fold increased the likelihood of hemotransfusion (OR, 4.74; 95 % CI, 3.12-7.19; р&lt;0.0001). Severe and moderate anemia (Hb &lt;90 g/l) was observed in 11.2 % of patients, which presence 6-fold increased the risk of brain dysfunction (OR, 5.72; 95 % CI, 2.17-15.06; р=0.001) and MOF (OR, 5.97; 95 % CI, 1.94-18.35; р=0.004) compared to patients with Hb 90-130 g/l.Conclusion      In patients with AHD, postoperative anemia increases the risk of circulatory decompensation at two days after the surgery and of MOF and also increases the likelihood of intraoperative hemotransfusion; postoperative anemia with Hb &lt;90 g/l increases the risk of brain damage and MOF.

Assessing the Utility of End-Tidal Carbon Dioxide as a Marker for Fluid Responsiveness in Cardiogenic Shock

Background

Preventing end-organ failure in patients with shock requires rapid and easily accessible measurements of fluid responsiveness. Unlike septic shock, not all patients in cardiogenic shock are preload responsive. We conducted this study to determine the discriminant power of changes in end-tidal carbon dioxide (ETCO₂), systolic blood pressure (SBP), inferior vena cava (IVC) collapsibility index (IVC-CI), and venous to arterial carbon dioxide (Pv-aCO₂) gap after a fluid challenge and compared it to increases in cardiac output.

Methodology

In a prospective, quasi-experimental design, mechanically ventilated patients in cardiogenic shock were assessed for fluid responsiveness by comparing improvement in cardiac output (velocity time integral) with changes in ETCO₂, heart rate, SBP, Pv-aCO₂ gap, IVC-CI after a fluid challenge (a crystalloid bolus or passive leg raise).

Results

Out of 60 patients, with mean age 61.3 ± 14.8 years, mean acute physiology and chronic health evaluation (APACHE) score ­14.82 ± 7.49, and median ejection fraction (EF) 25% (25-35), 36.7% (22) had non ST-segment elevation myocardial infarction (NSTEMI) and 60% (36) were ST-segment elevation myocardial infarction (STEMI). ETCO₂ was the best predictor of fluid responsiveness; area under the curve (AUC) 0.705 (95% confidence interval (CI) 0.57-0.83), p=0.007, followed by reduction in Pv-aCO₂ gap; AUC 0.598 (95% CI; 0.45-0.74), p= 0.202. Changes in SBP, mean arterial pressure (MAP), IVC-CI weren’t significant; 0.431 (p=0.367), 0.437 (p=0.410), 0.569 (p=0.367) respectively. The discriminant value identified for ETCO₂ was more than equal to 2 mmHg, with sensitivity 58.6%, specificity 80.7%, positive predictive value 73.9% [95% CI; 56.5% to 86.1%], negative predictive value 69.7% [95% CI; 56.7% to 76.9%].

Conclusions

Change in ETCO₂ is a useful bedside test to predict fluid responsiveness in cardiogenic shock.

Predictors of Hospital Mortality in Patients with Acute Coronary Syndrome Complicated by Cardiogenic Shock

As demonstrated by earlier studies, pre-hospital triage with trans-telephonic electrocardiogram (TTECG) and direct referral for catheter therapy shows great value in the management of out-of-hospital chest pain emergencies. It does not only improve in-hospital mortality in ST-segment elevation myocardial infarction, but it has also been identified as an independent predictor of higher in-hospital survival rate. Since TTECG-facilitated triage shortens both transport time and percutaneous coronary intervention (PCI)-related procedural time intervals, it was hypothesized that even high-risk patients with acute coronary syndrome (ACS) and cardiogenic shock (CS) might also benefit from TTECG-based triage. Here, we decided to examine our database for new triage- and left ventricular (LV) function-related parameters that can influence in-hospital mortality in ACS complicated by CS. ACS patients were divided into two groups, namely, (1) hospital death patients (n = 77), and (2) hospital survivors (control, n = 210). Interestingly, TTECG-based consultation and triage of CS and ACS patients were confirmed as significant independent predictors of lower hospital mortality risk (odds ratio (OR) 0.40, confidence interval (CI) 0.21–0.76, p = 0.0049). Regarding LV function and blood chemistry, a good myocardial reperfusion after PCI (high area at risk (AAR) blush score/AAR LV segment number; OR 0.85, CI 0.78–0.98, p = 0.0178) and high glomerular filtration rate (GFR) value at the time of hospital admission (OR 0.97, CI 0.96–0.99, p = 0.0042) were the most crucial independent predictors of a decreased risk of in-hospital mortality in this model. At the same time, a prolonged time interval between symptom onset and hospital admission, successful resuscitation, and higher peak creatine kinase activity were the most important independent predictors for an increased risk of in-hospital mortality. In ACS patients with CS, (1) an early TTECG-based teleconsultation and triage, as well as (2) good myocardial perfusion after PCI and a high GFR value at the time of hospital admission, appear as major independent predictors of a lower in-hospital mortality rate.

[Cardiogenic shock]

Cardiogenic shock (CS) is defined as end-organ hypoperfusion as the consequence of primary myocardial dysfunction. Among the diagnostic criteria are a systolic blood pressure < 90 mmHg, acute renal failure (oligoanuria), ischemic hepatitis, cyanosis and cold, clammy skin. Accepted hemodynamic cutoffs are a cardiac index < 2,2 (l/min)/m2 and a pulmonary capillary wedge pressure > 15 mmHg. It should be acknowledged, that a normal blood pressure does not rule out CS; there is a nonhypotensive variant of CS demonstrating all the signs mentioned above (including elevated lactate levels) while the blood pressure is compensated due to vasoconstriction.The single most frequent cause of CS is pump failure in the setting of an acute myocardial infarction and its mortality rate has been lowered to 40-50%, owing to the widespread availability of primary PCI. Regarding PCI, it has been demonstrated recently that a "culprit-lesion only strategy" should be followed in the setting of CS. Other important causes of CS to take into account are mechanical complications of myocardial infarction (papillary and ventricular septal rupture as well as rupture of the myocardial free wall leading to tamponade), valvular heart disease (mostly decompensated aortic stenosis) as well as myocarditis and end stage cardiomyopathy.The diagnosis of CS is made by patient history, physical examination, ECG, echocardiography and coronary angiography. Echocardiography should always be performed before coronary angiography because, in the case of mechanical complications, it significantly alters the management of the patients. Patients with clinical signs of CS but paradoxically preserved ejection fraction must be thoroughly evaluated for the presence of a papillary muscle rupture, particularly in the setting of a lateral wall infarction.Noradrenaline and dobutamine are the first-line agents for medical stabilization. When such conventional measures fail, extracorporeal support devices such as ECMO or Impella© may be used. Currently, trials are underway to assess wheter these devices confer a survival benefit in this high-risk population.

Acute Myocardial Infarction Complicated by Cardiogenic Shock: Analysis of the Position Statement From the European Society of Cardiology Acute Cardiovascular Care Association, With Perioperative Implications

Effective management of cardiogenic shock (CS) is hampered by a lack of evidence-based information. This is a high-mortality condition, without clear, evidence-based guidelines for perioperative management, specifically-a lack of target endpoints for treatment (e.g.: mean arterial pressure or oxygenation), utility of regional care systems or the benefits of palliative care. The Acute Cardiovascular Care Association (ACCA) of the European Society of Cardiology (ESC) recently published a position statement that aimed to offer contemporary guidance on the diagnosis and treatment of acute myocardial infarction (AMI) complicated by CS. Herein, we review this complex clinical topic and review the ACCA statement on AMI associated with CS, with a focus on relevance to perioperative management.

Dose Optimization of Cefpirome Based on Population Pharmacokinetics and Target Attainment during Extracorporeal Membrane Oxygenation

To obtain the optimal dosage regimen in patients receiving extracorporeal membrane oxygenation (ECMO), we developed a population pharmacokinetics model for cefpirome and performed pharmacodynamic analyses. This prospective study included 15 patients treated with cefpirome during ECMO. Blood samples were collected during ECMO (ECMO-ON) and after ECMO (ECMO-OFF) at predose and 0.5 to 1, 2 to 3, 4 to 6, 8 to 10, and 12 h after cefpirome administration. The population pharmacokinetic model was developed using nonlinear mixed effects modeling and stepwise covariate modeling. Monte Carlo simulation was used to assess the probability of target attainment (PTA) and cumulative fraction of response (CFR) according to the MIC distribution. Cefpirome pharmacokinetics were best described by a two-compartment model. Covariate analysis indicated that serum creatinine concentration (SCr) was negatively correlated with clearance, and the presence of ECMO increased clearance and the central volume of distribution. The simulations showed that patients with low SCr during ECMO-ON had lower PTA than patients with high SCr during ECMO-OFF; so, a higher dosage of cefpirome was required. Cefpirome of 2 g every 8 h for intravenous bolus injection or 2 g every 12 h for extended infusion over 4 h was recommended with normal kidney function receiving ECMO. We established a population pharmacokinetic model for cefpirome in patients with ECMO, and appropriate cefpirome dosage regimens were recommended. The impact of ECMO could be due to the change in patient status on consideration of the small population and uncertainty in covariate relationships. Dose optimization of cefpirome may improve treatment success and survival in patients receiving ECMO. (This study has been registered at ClinicalTrials.gov under identifier NCT02581280.).

Quantifying systemic congestion with Point-Of-Care ultrasound: development of the venous excess ultrasound grading system

Background

Organ congestion is a mediator of adverse outcomes in critically ill patients. Point-Of-Care ultrasound (POCUS) is widely available and could enable clinicians to detect signs of venous congestion at the bedside. The aim of this study was to develop several grading system prototypes using POCUS and to determine their respective ability to predict acute kidney injury (AKI) after cardiac surgery. This is a post-hoc analysis of a single-center prospective study in 145 patients undergoing cardiac surgery for which repeated daily measurements of hepatic, portal, intra-renal vein Doppler and inferior vena cava (IVC) ultrasound were performed during the first 72 h after surgery. Five prototypes of venous excess ultrasound (VExUS) grading system combining multiple ultrasound markers were developed.

Results

The association between each score and AKI was assessed using time-dependant Cox models as well as conventional performance measures of diagnostic testing. A total of 706 ultrasound assessments were analyzed. We found that defining severe venous congestion as the presence of severe flow abnormalities in multiple Doppler patterns with a dilated IVC (≥ 2 cm) showed the strongest association with the development of subsequent AKI compared with other combinations (HR: 3.69 CI 1.65–8.24 p = 0.001). The association remained significant after adjustment for baseline risk of AKI and vasopressor/inotropic support (HR: 2.82 CI 1.21–6.55 p = 0.02). Furthermore, this severe VExUS grade offered a useful positive likelihood ratio (+LR: 6.37 CI 2.19–18.50) when detected at ICU admission, which outperformed central venous pressure measurements.

Conclusions

The combination of multiple POCUS markers may identify clinically significant venous congestion.

Critical Illness-Related Corticosteroid Insufficiency in Cardiogenic Shock Patients: Prevalence and Prognostic Role

BACKGROUND

Cardiogenic shock shares with septic shock common hemodynamic features, inflammatory patterns, and most likely similar complications such as critical illness-related corticosteroid insufficiency. The aim of this study was to evaluate the prevalence of critical illness-related corticosteroid insufficiency in cardiogenic shock patients and to secondarily assess its prognostic value on 90-day mortality.

METHODS

A single-center prospective observational study conducted over a 3-year period and including all patients with cardiogenic shock. Main exclusion criteria were patients with prior cardiac arrest, sepsis, ongoing corticosteroid therapy, and etomidate administration. A short corticotropin test was performed in the first 24 h following admission. Serum cortisol levels were measured before (T0) and 60 min (T60) after administration of 250 μg of cosyntropin. Critical illness-related corticosteroid insufficiency was defined according to the 2017 consensus definition (basal total cortisol<10 μg·dL or a delta cortisol T60-T0<9 μg·dL) as well as the thresholds published in 2016 in cardiogenic shock patients associated with worst prognosis (basal total cortisol>29 μg·dL and delta cortisol T60-T0<17 μg·dL).

RESULTS

Seventy-nine consecutive patients hospitalized in intensive care for cardiogenic shock met the inclusion criteria. Overall mortality was 43% at day 90. Forty-two percent had critical illness-related corticosteroid insufficiency using the 2017 consensus definition and 32% using the 2016 cardiogenic shock thresholds. Presence of critical illness-related corticosteroid insufficiency was not an independent factor associated with 90-day mortality irrespective of the thresholds used.

CONCLUSION

Critical illness-related corticosteroid insufficiency is a frequent occurrence in medical cardiogenic shock. However, in this study, such insufficiency was not associated with prognosis.

MicroRNA-155 Amplifies Nitric Oxide/cGMP Signaling and Impairs Vascular Angiotensin II Reactivity in Septic Shock

OBJECTIVES

Septic shock is a life-threatening clinical situation associated with acute myocardial and vascular dysfunction, whose pathophysiology is still poorly understood. Herein, we investigated microRNA-155-dependent mechanisms of myocardial and vascular dysfunction in septic shock.

DESIGN

Prospective, randomized controlled experimental murine study and clinical cohort analysis.

SETTING

University research laboratory and ICU at a tertiary-care center.

PATIENTS

Septic patients, ICU controls, and healthy controls. Postmortem myocardial samples from septic and nonseptic patients. Ex vivo evaluation of arterial rings from patients undergoing coronary artery bypass grafting.

SUBJECTS

C57Bl/6J and genetic background-matched microRNA-155 knockout mice.

INTERVENTIONS

Two mouse models of septic shock were used. Genetic deletion and pharmacologic inhibition of microRNA-155 were performed. Ex vivo myographic studies were performed using mouse and human arterial rings.

MEASUREMENTS AND MAIN RESULTS

We identified microRNA-155 as a highly up-regulated multifunctional mediator of sepsis-associated cardiovascular dysfunction. In humans, plasma and myocardial microRNA-155 levels correlate with sepsis-related mortality and cardiac injury, respectively, whereas in murine models, microRNA-155 deletion and pharmacologic inhibition attenuate sepsis-associated cardiovascular dysfunction and mortality. MicroRNA-155 up-regulation in septic myocardium was found to be mostly supported by microvascular endothelial cells. This promoted myocardial microvascular permeability and edema, bioenergetic deterioration, contractile dysfunction, proinflammatory, and nitric oxide-cGMP-protein kinase G signaling overactivation. In isolate cardiac microvascular endothelial cells, microRNA-155 up-regulation significantly contributes to LPS-induced proinflammatory cytokine up-regulation, leukocyte adhesion, and nitric oxide overproduction. Furthermore, we identified direct targeting of CD47 by microRNA-155 as a novel mechanism of myocardial and vascular contractile depression in sepsis, promoting microvascular endothelial cell and vascular insensitivity to thrombospondin-1-mediated inhibition of nitric oxide production and nitric oxide-mediated vasorelaxation, respectively. Additionally, microRNA-155 directly targets angiotensin type 1 receptor, decreasing vascular angiotensin II reactivity. Deletion of microRNA-155 restored angiotensin II and thrombospondin-1 vascular reactivity in LPS-exposed arterial rings.

CONCLUSIONS

Our study demonstrates multiple new microRNA-155-mediated mechanisms of sepsis-associated cardiovascular dysfunction, supporting the translational potential of microRNA-155 inhibition in human septic shock.

Nonischemic Causes of Cardiogenic Shock

Although cardiogenic shock is uncommon in the emergency department, it is associated with high mortality. Most cardiogenic shock is caused by ischemia, but nonischemic etiologies are essential to recognize. Clinicians should optimize preload, contractility, and afterload. Volume-responsive patients should be resuscitated in small aliquots, although some patients may require diuresis to improve cardiac output. Vasopressors are important to restore end-organ perfusion, and inotropes improve contractility. Intubation and positive pressure ventilation impact hemodynamics, which, depending on volume status, may be beneficial or deleterious. Knowing indications for mechanical circulatory support is important for timely consultation or transfer as indicated.

Troubleshooting a dialysis line: when blue runs red

We present the case of a critically ill woman whose dialysis line was noted to be circulating bright red blood. Located in the right internal jugular vein, the line had previously been working normally with the change occurring shortly after the patient was liberated from positive pressure mechanical ventilation. An arterial malposition was ruled out and subsequent investigations revealed the presence of a left-sided partial anomalous pulmonary venous connection (PAPVC) that had been previously undiagnosed. The identification of a left-sided PAPVC from blood gas measurements taken from a right internal jugular vein dialysis catheter in this case provides an informative opportunity to consider the intricate physiological relationship between the respiratory and cardiovascular systems in critically ill patients requiring invasive procedures and treatments.

Extracorporeal Life Support: Physiological Concepts and Clinical Outcomes

Extracorporeal life support (ECLS) describes a system that involves drainage from the venous circulation and return via an oxygenator into the arterial circulation (veno-arterial extracorporeal membrane oxygenation). ECLS provides effective cardiopulmonary support, but the parallel circulation has complex effects on the systemic and pulmonary circulatory physiology. An understanding of the physiological changes is fundamental to the management of ECLS. In this review, the key physiological concepts and the implications on the clinical management of ECLS are discussed. In addition, the clinical outcomes associated with ECLS in cardiogenic shock are systematically reviewed. The paucity of clinical trials on ECLS highlights the need for randomized trials to guide the selection of patients.