Hemodynamic consequences of severe lactic acidosis in shock states: from bench to bedside

A recommendation for the use of electrical biosensing technology in neonatology

Non-invasive cardiac output monitoring, via electrical biosensing technology (EBT), provides continuous, multi-parameter hemodynamic variable monitoring which may allow for timely identification of hemodynamic instability in some neonates, providing an opportunity for early intervention that may improve neonatal outcomes. EBT encompasses thoracic (TEBT) and whole body (WBEBT) methods. Despite the lack of relative accuracy of these technologies, as compared to transthoracic echocardiography, the use of these technologies in neonatology, both in the research and clinical arena, have increased dramatically over the last 30 years. The European Society of Pediatric Research Special Interest Group in Non-Invasive Cardiac Output Monitoring, a group of experienced neonatologists in the field of EBT, deemed it appropriate to provide recommendations for the use of TEBT and WBEBT in the field of neonatology. Although TEBT is not an accurate determinant of cardiac output or stroke volume, it may be useful for monitoring longitudinal changes of hemodynamic parameters. Few recommendations can be made for the use of TEBT in common neonatal clinical conditions. It is recommended not to use WBEBT to monitor cardiac output. The differences in technologies, study methodologies and data reporting should be addressed in ongoing research prior to introducing EBT into routine practice. IMPACT STATEMENT: TEBT is not recommended as an accurate determinant of cardiac output (CO) (or stroke volume (SV)). TEBT may be useful for monitoring longitudinal changes from baseline of hemodynamic parameters on an individual patient basis. TEBT-derived thoracic fluid content (TFC) longitudinal changes from baseline may be useful in monitoring progress in respiratory disorders and circulatory conditions affecting intrathoracic fluid volume. Currently there is insufficient evidence to make any recommendations regarding the use of WBEBT for CO monitoring in neonates. Further research is required in all areas prior to the implementation of these monitors into routine clinical practice.

Jehovah's Witness Needing Critical Care: A Narrative Review on the Expanding Arsenal

Present day Jehovah's Witness (JW) religion accounts for 8.5 million followers. A tenant feature of the JW faith is religious objection to transfusions of blood and blood products. Interpatient variability, as it pertains to blood and blood products may occur; hence, a confidential interview will determine which products individual may consent to (Marsh and Bevan, 2002). This belief and practice place great restrictions on treating medical professionals in scenarios of life-threatening anaemia and active haemorrhage. The review to follow explores the physiological and pathophysiological consequences of severe anaemia. Non-blood transfusion practices are explored, many of which are potentially lifesaving. Particular attention is drawn to the evolving science involving artificial oxygen carriers and their use in emergency situations. A greater safety profile ensures its future use amongst religious objectors to be greatly beneficial. Intravenous iron supplementation has enjoyed a lively debate within the critical care community. A review of recent systematic and meta-analysis supports its use in the ICU; however, more investigation is needed into the complementary use of hepcidin.

Evaluating the predictive value of initial lactate/albumin ratios in determining prognosis of sepsis patients

Sepsis remains a significant clinical challenge owing to its complex pathophysiology and variable prognosis. The early identification of patients at a higher risk of poor outcomes can be crucial for improving treatment strategies. This study aimed to evaluate the predictive value of early serum lactate and albumin levels and the lactate/albumin (L/A) ratio for 28-day prognosis in patients with sepsis. Patients diagnosed with sepsis between January 2021 and December 2022 were evaluated using a retrospective cohort methodology. Inclusion followed the International Consensus on sepsis and septic shock (Sepsis-3) guidelines and patients were selected based on well-defined criteria. Variables such as lactate, albumin, and the L/A ratio were documented within the first 24 hours of admission. Statistical analyses were performed using various tools, including the nonparametric Mann-Whitney U test and receiver operating characteristic curves. A total of 301 patients were divided into the survival (n = 167) and death (n = 134) groups. Notable differences were detected in the incidence of pulmonary infection, shock, lactate, albumin, and the L/A ratio. The L/A ratio was identified as a key predictor with an area under the curve of 0.868, an optimal cutoff value of >0.17, a sensitivity of 56.21%, and a specificity of 94.18%. Significant disparities in mortality rates and survival times were observed for the lactate, albumin, and L/A levels. This study underscores the predictive value of early serum lactate and albumin levels and the L/A ratio for 28-day prognosis in patients with sepsis, with the L/A ratio showing a superior predictive capability. These findings highlight the importance of L/A ratio as a robust and precise marker for evaluating the future clinical course of patients with sepsis, potentially aiding early detection and management.

Implications for neutrophils in cardiac arrhythmias

Cardiac arrhythmias commonly occur as a result of aberrant electrical impulse formation or conduction in the myocardium. Frequently discussed triggers include underlying heart diseases such as myocardial ischemia, electrolyte imbalances, or genetic anomalies of ion channels involved in the tightly regulated cardiac action potential. Recently, the role of innate immune cells in the onset of arrhythmic events has been highlighted in numerous studies, correlating leukocyte expansion in the myocardium to increased arrhythmic burden. Here, we aim to call attention to the role of neutrophils in the pathogenesis of cardiac arrhythmias and their expansion during myocardial ischemia and infectious disease manifestation. In addition, we will elucidate molecular mechanisms associated with neutrophil activation and discuss their involvement as direct mediators of arrhythmogenicity.

Association between lactic acidosis and multiple organ dysfunction syndrome after cardiopulmonary bypass

Background

The relationship between hyperlactatemia and prognosis after cardiopulmonary bypass (CPB) is controversial, and some studies ignore the presence of lactic acidosis in patients with severe hyperlactacemia. This study explored the association between lactic acidosis (LA) and the occurrence of multiple organ dysfunction syndrome (MODS) after cardiopulmonary bypass.

Methods

This study was a post hoc analysis of patients who underwent cardiac surgery between February 2017 and August 2018 and participated in a prospective study at Taizhou Hospital. The data were collected at: ICU admission (H0), and 4, 8, 12, 24, and 48 h after admission. Blood lactate levels gradually increased after CPB, peaking at H8 and then gradually decreasing. The patients were grouped as LA, hyperlactatemia (HL), and normal control (NC) based on blood test results 8 h after ICU admission. Basic preoperative, perioperative, and postoperative conditions were compared between the three groups, as well as postoperative perfusion and oxygen metabolism indexes.

Results

There were 22 (19%), 73 (64%), and 19 (17%) patients in the LA, HL, and NC groups, respectively. APACHE II (24h) and SOFA (24h) scores were the highest in the LA group (P < 0.05). ICU stay duration was the longest for the LA group (48.5 (42.5, 50) h), compared with the HL (27 (22, 48) h) and NC (27 (25, 46) h) groups (P = 0.012). The LA group had the highest incidence of MODS (36%), compared with the HL (14%) and NC (5%) groups (P = 0.015). In the LA group, the oxygen extraction ratio (O2ER) was lower (21.5 (17.05, 32.8)%) than in the HL (31.3 (24.8, 37.6)%) and the NC group (31.3 (29.0, 35.4) %) (P = 0.018). In the univariable analyses, patient age (OR = 1.054, 95% CI [1.003-1.109], P = 0.038), the LA group (vs. the NC group, (OR = 10.286, 95% CI [1.148-92.185], P = 0.037), and ΔPCO2 at H8 (OR = 1.197, 95% CI [1.022-1.401], P = 0.025) were risk factor of MODS after CPB.

Conclusions

We speculated that there was correlation between lactic acidosis and MODS after CPB. In addition, LA should be monitored intensively after CPB.

Damage Control Surgery and Transfer in Emergency General Surgery

Selective non traumatic emergency surgery patients are targets for damage control surgery (DCS) to prevent or treat abdominal compartment syndrome and the lethal triad. However, DCS is still a subject of controversy. As a concept, DCS describes a series of abbreviated surgical procedures to allow rapid source control of hemorrhage and contamination in patients with circulatory shock to allow resuscitation and stabilization in the intensive care unit followed by delayed return to the operating room for definitive surgical management once the patient becomes physiologic stable. If appropriately applied, the DCS morbidity and mortality can be significantly reduced.

Impact of decreased levels of total CO2 on in-hospital mortality in patients with COVID-19

Decreased total CO2 (tCO2) is significantly associated with all-cause mortality in critically ill patients. Because of a lack of data to evaluate the impact of tCO2 in patients with COVID-19, we assessed the impact of tCO2 on all-cause mortality in this study. We retrospectively reviewed the data of hospitalized patients with COVID-19 in two Korean referral hospitals between February 2020 and September 2021. The primary outcome was in-hospital mortality. We assessed the impact of tCO2 as a continuous variable on mortality using the Cox-proportional hazard model. In addition, we evaluated the relative factors associated with tCO2 ≤ 22 mmol/L using logistic regression analysis. In 4,423 patients included, the mean tCO2 was 24.8 ± 3.0 mmol/L, and 17.9% of patients with tCO2 ≤ 22 mmol/L. An increase in mmol/L of tCO2 decreased the risk of all-cause mortality by 4.8% after adjustment for age, sex, comorbidities, and laboratory values. Based on 22 mmol/L of tCO2, the risk of mortality was 1.7 times higher than that in patients with lower tCO2. This result was maintained in the analysis using a cutoff value of tCO2 24 mmol/L. Higher white blood cell count; lower hemoglobin, serum calcium, and eGFR; and higher uric acid, and aspartate aminotransferase were significantly associated with a tCO2 value ≤ 22 mmol/L. Decreased tCO2 significantly increased the risk of all-cause mortality in patients with COVID-19. Monitoring of tCO2 could be a good indicator to predict prognosis and it needs to be appropriately managed in patients with specific conditions.

Factors to consider during anesthesia in patients undergoing preemptive kidney transplantation: a propensity-score matched analysis

BACKGROUND

International guidelines have recommended preemptive kidney transplantation (KT) as the preferred approach, advocating for transplantation before the initiation of dialysis. This approach is advantageous for graft and patient survival by avoiding dialysis-related complications. However, recipients of preemptive KT may undergo anesthesia without the opportunity to optimize volume status or correct metabolic disturbances associated with end-stage renal disease. In these regard, we aimed to investigate the anesthetic events that occur more frequently during preemptive KT compared to nonpreemptive KT.

METHODS

This is a single-center retrospective study. Of the 672 patients who underwent Living donor KT (LDKT), 388 of 519 who underwent nonpreemptive KT were matched with 153 of 153 who underwent preemptive KT using propensity score based on preoperative covariates. The primary outcome was intraoperative hypotension defined as area under the threshold (AUT), with a threshold set at a mean arterial blood pressure below 70 mmHg. The secondary outcomes were intraoperative metabolic acidosis estimated by base excess and serum bicarbonate, electrolyte imbalance, the use of inotropes or vasopressors, intraoperative transfusion, immediate graft function evaluated by the nadir creatinine, and re-operation due to bleeding.

RESULTS

After propensity score matching, we analyzed 388 and 153 patients in non-preemptive and preemptive groups. The multivariable analysis revealed the AUT of the preemptive group to be significantly greater than that of the nonpreemptive group (mean ± standard deviation, 29.7 ± 61.5 and 14.5 ± 37.7, respectively, P = 0.007). Metabolic acidosis was more severe in the preemptive group compared to the nonpreemptive group. The differences in the nadir creatinine value and times to nadir creatinine were statistically significant, but clinically insignificant.

CONCLUSION

Intraoperative hypotension and metabolic acidosis occurred more frequently in the preemptive group during LDKT. These findings highlight the need for anesthesiologists to be prepared and vigilant in managing these events during surgery.

State of Shock: Contemporary Vasopressor and Inotrope Use in Cardiogenic Shock

Cardiogenic shock is characterized by tissue hypoxia caused by circulatory failure arising from inadequate cardiac output. In addition to treating the pathologic process causing impaired cardiac function, prompt hemodynamic support is essential to reduce the risk of developing multiorgan dysfunction and to preserve cellular metabolism. Pharmacologic therapy with the use of vasopressors and inotropes is a key component of this treatment strategy, improving perfusion by increasing cardiac output, altering systemic vascular resistance, or both, while allowing time and hemodynamic stability to treat the underlying disease process implicated in the development of cardiogenic shock. Despite the use of mechanical circulatory support recently garnering significant interest, pharmacologic hemodynamic support remains a cornerstone of cardiogenic shock management, with over 90% of patients receiving at least 1 vasoactive agent. This review aims to describe the pharmacology and hemodynamic effects of current pharmacotherapies and provide a practical approach to their use, while highlighting important future research directions.

A Review of Bicarbonate Use in Common Clinical Scenarios

BACKGROUND

The use of sodium bicarbonate to treat metabolic acidosis is intuitive, yet data suggest that not all patients benefit from this therapy.

OBJECTIVE

In this narrative review, we describe the physiology behind commonly encountered nontoxicologic causes of metabolic acidosis, highlight potential harm from the indiscriminate administration of sodium bicarbonate in certain scenarios, and provide evidence-based recommendations to assist emergency physicians in the rational use of sodium bicarbonate.

DISCUSSION

Sodium bicarbonate can be administered as a hypertonic push, as a resuscitation fluid, or as an infusion. Lactic acidosis and cardiac arrest are two common scenarios where there is limited benefit to routine use of sodium bicarbonate, although certain circumstances, such as patients with concomitant acute kidney injury and lactic acidosis may benefit from sodium bicarbonate. Patients with cardiac arrest secondary to sodium channel blockade or hyperkalemia also benefit from sodium bicarbonate therapy. Recent data suggest that the use of sodium bicarbonate in diabetic ketoacidosis does not confer improved patient outcomes and may cause harm in pediatric patients. Available evidence suggests that alkalinization of urine in rhabdomyolysis does not improve patient-centered outcomes. Finally, patients with a nongap acidosis benefit from sodium bicarbonate supplementation.

CONCLUSIONS

Empiric use of sodium bicarbonate in patients with nontoxicologic causes of metabolic acidosis is not warranted and likely does not improve patient-centered outcomes, except in select scenarios. Emergency physicians should reserve use of this medication to conditions with clear benefit to patients.

Risk Factors in HIV-1 Positive Patients on the Intensive Care Unit: A Single Center Experience from a Tertiary Care Hospital

HIV-positive patients with acquired immunodeficiency syndrome (AIDS) often require treatment on intensive care units (ICUs). We aimed to present data from a German, low-incidence region cohort, and subsequently evaluate factors measured during the first 24 h of ICU stay to predict short- and long-term survival, and compare with data from high-incidence regions. We documented 62 patient courses between 2009 and 2019, treated on a non-operative ICU of a tertiary care hospital, mostly due to respiratory deterioration and co-infections. Of these, 54 patients required ventilatory support within the first 24 h with either nasal cannula/mask (n = 12), non-invasive ventilation (n = 16), or invasive ventilation (n = 26). Overall survival at day 30 was 77.4%. While ventilatory parameters (all p < 0.05), pH level (c/o 7.31, p = 0.001), and platelet count (c/o 164,000/µL, p = 0.002) were significant univariate predictors of 30-day and 60-day survival, different ICU scoring systems, such as SOFA score, APACHE II, and SAPS 2 predicted overall survival (all p < 0.001). Next to the presence or history of solid neoplasia (p = 0.026), platelet count (HR 6.7 for <164,000/µL, p = 0.020) and pH level (HR 5.8 for <7.31, p = 0.009) remained independently associated with 30-day and 60-day survival in multivariable Cox regression. However, ventilation parameters did not predict survival multivariably.

Biochemical disturbance in damage control resuscitation: mechanisms, management and prognostic utility

PURPOSE OF REVIEW

With advances in resuscitative techniques, trauma patients are surviving increasingly severe injuries and physiological insult. Timely recognition of futility remains important in terms of patient dignity and resource preservation yet is increasingly challenging in the face of these advances. The understanding of biochemical derangement from pathophysiological processes of trauma and iatrogenic effects of resuscitation has expanded recently.

RECENT FINDINGS

Acidosis and hypocalcaemia have been recognized as important contributors to mortality among trauma patients. Although less well recognized and studied, critical injury and high blood product volume resuscitation render patients vulnerable to life-threatening hyperkalaemia. The methods of correcting disruptions to acid-base and electrolyte homeostasis during damage control resuscitation have changed little recently and often rely on evidence from undifferentiated populations. Biochemical disturbances have value as ancillary predictors of futility in trauma resuscitation.

SUMMARY

These findings will contribute to a greater understanding among anaesthesiologists of the causative mechanisms and effects of biochemical derangement after severe injury and aid them in the delivery of well tolerated and effective damage control resuscitation. Gaps in the evidence base are highlighted to encourage future work.

Metabolic Acidosis in Children: A Literature Review

Metabolic acidosis is characterised by a primary decrease in the serum bicarbonate concentration, a secondary decrease in the arterial partial pressure of CO­2, and a reduction in blood pH. Metabolic acidosis, acute or chronic, may have deleterious effects on cellular function and cause increased morbidity and mortality. A systematic review of the available literature was performed to identify data on the prevalence, manifestations, cause, outcomes, and treatment of metabolic acidosis in children. Online databases (Ovid Medline, Embase, and PubMed), commercial search engines (including Google), and chapters on metabolic acidosis in the standard textbooks of paediatrics and medicine were reviewed. Systematic approach to acute metabolic acidosis starts with proper history taking and examination. This is followed by assessment of acid-base parameters, including pH, partial pressure of CO2, and bicarbonate concentration in arterial blood. Blood gas is needed to differentiate primary metabolic acidosis from compensated respiratory alkalosis. Once the diagnosis of a metabolic acidosis has been confirmed, serum electrolyte values are used to determine the serum anion gap. The various causes of increased and normal anion gap metabolic acidosis have been discussed in the article. The main aim of treatment in metabolic acidosis is to reverse the primary pathophysiology. In acute metabolic acidosis, sodium bicarbonate therapy is not beneficial due to potential complications and is reserved for specific situations. Base therapy is used in chronic metabolic acidosis where it ameliorates many of its untoward effects. Other modalities of treatment of metabolic acidosis include peritoneal or haemodialysis and tris-hydroxymethyl aminomethane.

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

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

Development of a prehospital lactic acidosis score for early-mortality. A prospective, multicenter, ambulance-based, cohort study

BACKGROUND

Lactic acidosis is a clinical status related to clinical worsening. Actually, higher levels of lactate is a well-established trigger of emergency situations. The aim of this work is to build-up a prehospital early warning score to predict 2-day mortality and intensive care unit (ICU) admission, constructed with other components of the lactic acidosis besides the lactate.

METHODS

Prospective, multicenter, observational, derivation-validation cohort study of adults evacuated by ambulance and admitted to emergency department with acute diseases, between January 1st, 2020 and December 31st, 2021. Including six advanced life support, thirty-eight basic life support units, referring to four hospitals (Spain). The primary and secondary outcome of the study were 2-day all-cause mortality and ICU-admission. The prehospital lactic acidosis (PLA) score was derived from the analysis of prehospital blood parameters associated with the outcome using a logistic regression. The calibration, clinical utility, and discrimination of PLA were determined and compared to the performance of each component of the score alone.

RESULTS

A total of 3334 patients were enrolled. The final PLA score included: lactate, pCO2, and pH. For 2-day mortality, the PLA showed an AUC of 0.941 (95%CI: 0.914-0.967), a better performance in calibration, and a higher net benefit as compared to the other score components alone. For the ICU admission, the PLA only showed a better performance for AUC: 0.75 (95%CI: 0.706-0.794).

CONCLUSIONS

Our results showed that PLA predicts 2-day mortality better than other lactic acidosis components alone. Including PLA score in prehospital setting could improve emergency services decision-making.

Echocardiographic Assessment of Patients with Glycogen Storage Disease in a Single Center

Glycogen storage disease (GSD) is a hereditary metabolic disorder caused by enzyme deficiency resulting in glycogen accumulation in the liver, muscle, heart, or kidney. GSD types II, III, IV, and IX are associated with cardiac involvement. However, cardiac manifestation in other GSD types is unclear. This study aimed to describe whether energy deprivation and the toxic effects of accumulated glycogen affect the heart of patients with GSD. We evaluated the left ventricle (LV) wall mass, LV systolic and diastolic function and myocardial strain with conventional echocardiography and two-dimensional speckle-tracking echocardiography (2D STE) in 62 patients with GSD type I, III, VI and IX who visited the Wonju Severance Hospital in 2021. Among the GSD patients, the echocardiographic parameters of 55 pediatrics were converted into z-scores and analyzed. Of the patients, 43 (62.3%), 7 (11.3%) and 12 (19.4%) patients were diagnosed with GSD type I, type III, and type IX, respectively. The median age was 9 years (range, 1-36 years), with 55 children under 18 years old and seven adults over 18 years. For the 55 pediatric patients, the echocardiographic parameters were converted into a z-score and analyzed. Multiple linear regression analysis showed that the BMI z-score (p = 0.022) and CK (p = 0.020) predicted increased LV mass z-score, regardless of GSD type. There was no difference in the diastolic and systolic functions according to myocardial thickness; however, 2D STE showed a negative correlation with the LV mass (r = -0.28, p = 0.041). Given that patients with GSD tend to be overweight, serial evaluation with echocardiography might be required for all types of GSD.

Twin Premature Infants With Riboflavin and Biotin Deficiency Presenting With Refractory Lactic Acidosis, Rash, and Multiorgan Failure During Prolonged Parenteral Nutrition

We are reporting monochorionic, diamniotic twin premature infants born at 25 weeks and 6 days gestation with riboflavin (vitamin B2) and biotin (vitamin B7) deficiency, while on prolonged total parenteral nutrition (TPN) during vitamin shortage. They presented initially with skin rash, lactic acidosis, and thrombocytopenia. Both twins progressed to severe respiratory failure, severe lactic acidosis, with refractory vasodilatory shock, pancytopenia, ischemic bowel injury, acute kidney injury, liver injury, and capillary leak syndrome leading to death of twin A. The surviving twin B was diagnosed with riboflavin and biotin deficiency that presented with abnormal metabolic work up suggestive of maple syrup urine disease, glutaric acidemia type 2, and X-linked adrenoleukodystrophy. Twin B was started on riboflavin and biotin supplementation at 41 days of life, with rapid improvement in clinical findings and laboratory abnormalities within days of starting biotin and riboflavin supplementation. He was discharged home in stable condition at 49 weeks of postmenstrual age.

Sodium bicarbonate administration is associated with improved survival in asystolic and PEA Out-of-Hospital cardiac arrest

BACKGROUND

Sodium bicarbonate ("bicarb") administration in out-of-hospital cardiac arrest (OHCA) is intended to counteract acidosis, although there is limited clinical evidence to support its routine administration. We sought to analyze the association of bicarb with resuscitation outcomes in non-traumatic OHCA.

METHODS

Records were obtained from the 2019-2020 ESO Data Collaborative prehospital electronic health record database, spanning 1,322 agencies in 50 states. OHCAs with resuscitations lasting 5-40 minutes were stratified by presenting ECG rhythm (VF/VT, pulseless electrical activity (PEA), asystole) for analysis. The outcomes of any prehospital ROSC and survival to discharge were compared by bicarb status using propensity score matching and logistic regressions with/without adjustment.

RESULTS

We analyzed 23,567 records, 6,663 (28.3 %) of which included bicarb administration. Most patients presented in asystole (67.4 %), followed by PEA (16.6 %), and VF/VT (15.1 %). In the propensity-matched cohort, ROSC was higher in the bicarb group for the asystole group (bicarb 10.6 % vs control 8.8 %; p = 0.013), without differences in the PEA or VF/VT groups. Survival was higher in the bicarb group for asystole (bicarb 3.3 % vs control 2.4 %; p = 0.020) and for PEA (bicarb 8.1 % vs control 5.4 %; p = 0.034), without differences in the VF/VT group. These results were consistent across adjusted/unadjusted logistic regression analyses: bicarb was associated with ROSC and survival in asystole [uOR (95 % CI): ROSC 1.23 (1.04-1.44), survival 1.40 (1.05-1.87)] and with survival in PEA (1.54 (1.03-2.31).

CONCLUSIONS

Bicarb was associated with survival in non-shockable rhythms and ROSC in asystole. Findings from this observational study should be corroborated with prospective randomized work.

Hemodynamic effects and tolerance of dobutamine for myocardial dysfunction during septic shock: An observational multicenter prospective echocardiographic study

Background

The role of dobutamine during septic shock resuscitation is still controversial.

Methods

The aim of this prospective multicentre study was to comprehensively characterize the hemodynamic response of septic shock patients with systolic myocardial dysfunction to incremental doses of dobutamine (0, 5, 10, and 15 μg/kg/min).

Results

Thirty two patients were included in three centers. Dobutamine significantly increased contractility indices of both ventricles [crude and afterload-adjusted left ventricular (LV) ejection fraction, global LV longitudinal peak systolic strain, tissue Doppler peak systolic wave at mitral and tricuspid lateral annulus, and tricuspid annular plane excursion) as well as global function indices (stroke volume and cardiac index) and diastolic function (increased e' and decreased E/e' ratio at lateral mitral annulus). Dobutamine also induced a significant decrease in arterial pressure and cardiac afterload indices (effective arterial elastance, systemic vascular resistance and diastolic shock index). Oxygen transport, oxygen consumption and carbon dioxide production all increased with dobutamine, without change in the respiratory quotient or lactate. Dobutamine was discontinued for poor tolerance in a majority of patients (n = 21, 66%) at any dose and half of patients (n = 15, 47%) at low-dose (5 μg/kg/min). Poor tolerance to low-dose dobutamine was more frequent in case of acidosis, was associated with lower vasopressor-free days and survival at day-14.

Conclusion

In patients with septic myocardial dysfunction, dobutamine induced an overall improvement of echocardiographic parameters of diastolic and systolic function, but was poorly tolerated in nearly two thirds of patients, with worsening vasoplegia. Patients with severe acidosis seemed to have a worse response to dobutamine.

Efficacy of Tranexamic Acid in Blood Versus Crystalloid-Resuscitated Trauma/Hemorrhagic Shock

INTRODUCTION

Whole blood (WB) or blood products are not always immediately available for repletion of lost intravascular volume in trauma/hemorrhagic shock (T/HS), and thus, resuscitation with crystalloid solutions is often necessary. Recently, we have shown enteral tranexamic acid (TXA) to be effective as a mild protease inhibitor in blood-resuscitated T/HS by counteracting proteolytic activity in and leaking from the gut with resultant preservation of systemic vascular integrity. We hypothesized that enteral TXA would improve hemodynamic stability after T/HS in the absence of blood reperfusion.

METHODS

We directly compared resuscitation with enteral TXA versus intravenous (IV) TXA in conjunction with lactated Ringer's solution (LR) or WB reperfusion in an experimental T/HS model. Rats were subjected to laparotomy and exsanguinated to a mean arterial blood pressure of 35-40 mm Hg for 90 min, followed by LR or WB reperfusion and monitored for 120 min. TXA was administered via IV (10 mg/kg) or enteral infusion (150 mM) 20 min after establishment of hemorrhage for 150 min.

RESULTS

Animals resuscitated with LR were unable to restore or maintain a survivable mean arterial blood pressure (>65 mm Hg), regardless of TXA treatment route. In contrast, rats reperfused with WB and given TXA either enterally or IV displayed hemodynamic improvements superior to WB controls.

CONCLUSIONS

Results suggest that the beneficial hemodynamic responses to enteral or IV TXA after experimental T/HS depend upon reperfusion of WB or components present in WB as TXA, regardless of delivery mode, does not have appreciable hemodynamic effects when paired with LR reperfusion.

Association Between the Acidemia, Lactic Acidosis, and Shock Severity With Outcomes in Patients With Cardiogenic Shock

Background

Lactic acidosis is associated with mortality in patients with cardiogenic shock (CS). Elevated lactate levels and systemic acidemia (low blood pH) have both been proposed as drivers of death. We, therefore, analyzed the association of both high lactate concentrations and low blood pH with 30‐day mortality in patients with CS.

Methods and Results

This was a 2‐center historical cohort study of unselected patients with CS with available data for admission lactate level or blood pH. CS severity was graded using the Society for Cardiovascular Angiography and Intervention (SCAI) shock classification. All‐cause survival at 30 days was analyzed using Kaplan‐Meier curves and Cox proportional‐hazards analysis. There were 1814 patients with CS (mean age, 67.3 years; 68.5% men); 51.8% had myocardial infarction and 53.0% had cardiac arrest. The distribution of SCAI shock stages was B, 10.8%; C, 30.7%; D, 38.1%; and E, 18.7%. In both cohorts, higher lactate or lower pH predicted a higher risk of adjusted 30‐day mortality. Patients with a lactate ≥5 mmol/L or pH <7.2 were at increased risk of adjusted 30‐day mortality; patients with both lactate ≥5 mmol/L and pH <7.2 had the highest risk of adjusted 30‐day mortality. Patients in SCAI shock stages C, D, and E had higher 30‐day mortality in each SCAI shock stage if they had lactate ≥5 mmol/L or pH <7.2, particularly if they met both criteria.

Conclusions

Higher lactate and lower pH predict mortality in patients with cardiogenic shock beyond standard measures of shock severity. Severe lactic acidosis may serve as a risk modifier for the SCAI shock classification. Definitions of refractory or hemometabolic shock should include high lactate levels and low blood pH.

A Review of Push-Dose Vasopressors in the Peri-operative and Critical Care Setting

During hospitalization, the risk of hypotension and associated sequelae remain important considerations for patient outcomes. The use of push-dose vasopressors (PDP) outside of the operating room has increased in recent years to combat the negative effects of hypotension. This narrative review evaluates the utility of PDP in its traditional perioperative setting as well as in areas of increasing use such as the emergency department and intensive care unit. Articles evaluating PDP highlight successful increases in blood pressure with all agents but differ in rates of adverse events and most lack direct comparison of PDP agents in regard to safety and efficacy. Agents utilized as PDP, including epinephrine, phenylephrine, norepinephrine, vasopressin, and ephedrine vary in mechanism of action, onset of action, and duration of action. These variations in pharmacology along with published literature may lead to differences in the preferred PDP for various clinical scenarios. Many adverse events associated with PDP have been due to dosing errors highlighting the importance of education surrounding the use of these agents. Additional research is necessary to further elucidate the risks and benefits of PDP in clinical practice, and to determine which PDP is truly preferred. Careful consideration should be given when determining the appropriateness of this administration method of vasopressors in various clinical scenarios.

Effectiveness of Sodium Bicarbonate Infusion on Mortality in Critically Ill Children With Metabolic Acidosis

Objective: Metabolic acidosis often occurs in the paediatric intensive care unit (PICU). Although sodium bicarbonate (SB) has been widely used in paediatrics, data on the effect of SB on children with metabolic acidosis in the PICU are scarce.

Methods: Patients with metabolic acidosis who were treated with SB within 48 h of PICU admission were screened. Multivariate logistic regression, subgroup analysis, and propensity score matching (PSM) were used to investigate the relationships between SB infusion and clinical outcomes.

Results: A total of 1,595 patients with metabolic acidosis were enrolled in this study. In the multivariate logistic regression model, SB infusion was not correlated with in-hospital mortality (odds ratio (OR) 0.87, 95% confidence interval (CI) 0.47–1.63, p = 0.668), but was significantly correlated with hypernatraemia (OR 1.98, 95% CI 1.14–3.46, p = 0.016), hypokalaemia (OR 2.01, 95% CI 1.36–2.96, p < 0.001), and hypocalcaemia (OR 4.29, 95% CI 2.92–6.31, p < 0.001). In the pH value, lactate level, acute kidney injury level, age grouping, and anion gap level subgroups, the ORs for SB and in-hospital mortality were not statistically significant. After PSM, the results remained unchanged.

Conclusion: SB infusion does not reduce the in-hospital mortality of severely ill children with metabolic acidosis and increases the risk of hypernatraemia, hypokalaemia, and hypocalcaemia. More effort should be focused on eliminating the causes of metabolic acidosis rather than SB infusion.

Rapid Classification and Treatment Algorithm of Cardiogenic Shock Complicating Acute Coronary Syndromes: The SAVE ACS Classification

Introduction. We aimed to identify the independent “frontline” predictors of 30-day mortality in patients with acute coronary syndromes (ACS) and propose a rapid cardiogenic shock (CS) classification and management pathway. Materials and Methods. From 2011 to 2019, a total of 11439 incident ACS patients were treated in our institution. Forward conditional logistic regression analysis was performed to determine the “frontline” predictors of 30 day mortality. The C-statistic assessed the discriminatory power of the model. As a validation cohort, we used 431 incident ACS patients admitted from January 1, 2020, to July 20, 2020. Results. Independent predictors of 30-day mortality included age (OR 1.05; 95% CI 1.04 to 1.07, $p<0.001$ ), intubation (OR 7.4; 95% CI 4.3 to 12.74, $p<0.001$ ), LV systolic impairment (OR severe_vs_normal 1.98; 95% CI 1.14 to 3.42, $p=0.015$ , OR moderate_vs_normal 1.84; 95% CI 1.09 to 3.1, $p=0.022$ ), serum lactate (OR 1.25; 95% CI 1.12 to 1.41, $p<0.001$ ), base excess (OR 1.1; 95% CI 1.04 to 1.07, $p<0.001$ ), and systolic blood pressure (OR 0.99; 95% CI 0.982 to 0.999, $p=0.024$ ). The model discrimination was excellent with an area under the curve (AUC) of 0.879 (0.851 to 0.908) ( $p<0.001$ ). Based on these predictors, we created the SAVE (SBP, Arterial blood gas, and left Ventricular Ejection fraction) ACS classification, which showed good discrimination for 30-day AUC 0.814 (0.782 to 0.845) and long-term mortality $\left(p_{\log -\text{rank}}<0.001\right)$ . A similar AUC was demonstrated in the validation cohort (AUC 0.815). Conclusions. In the current study, we introduce a rapid way of classifying CS using frontline parameters. The SAVE ACS classification could allow for future randomized studies to explore the benefit of mechanical circulatory support in different CS stages in ACS patients.

Usefulness of lactate albumin ratio at admission to predict 28-day mortality in critically ill severely burned patients: A retrospective cohort study

INTRODUCTION

Lactate albumin ratio (LAR) has been used as a prognostic marker associated with organ failure in critically ill septic patients. LAR and its association with outcomes has never been studied in burned patients. The aim of this study was to evaluate the ability of LAR to predict 28-day mortality.

METHODS

A retrospective cohort study including all burn patients hospitalized in intensive care unit. The primary endpoint was the 28-day mortality.

RESULTS

One thousand three hundred thirty four patients were screened, and 471 were included between June 2012 and December 2018. Briefly, the population study was mainly composed by men (249, 59.1%), the median age, TBSA burned, full thickness, ABSI and IGS2 were 52 [34-68], 20 [10-40], 8 [1-23], 7 [5-9] and 25 [15-40] respectively. Fifty-two patients (12.4%) died at day 28 after admission. At admission, the LAR level was lower in 28-day survivors compared non-survivors (0.05 [0.04, 0.08] vs 0.12 [0.07, 0.26], p < 0.001 respectively). In multivariate analysis accounting for ABSI, LAR levels at admission> 0.13 was independently associated with 28-day mortality (adjusted OR = 3.98 (IC95 1.88-8.35)). The ability of LAR at admission to discriminate 28-day mortality showed an AUC identical when compared to SOFA and ABSI scores (0.81 (IC95 0.74-0.88), 0.80 (IC95 0.72-0.85) and (0.85 (IC95 0.80-0.90), p < 0.05, respectively). Patients with LAR levels ≥ 0.13 at admission had higher 28-day mortality (40.6% vs 6.8%, p < 0.001, HR 7.39 (IC95 4.28-12.76)).

CONCLUSION

At admission, LAR is an easy and reliable marker independently associated to 28-day mortality in patients with severe burn injury, but prediction by LAR does not perform better than lactate level alone.

Laboratory Markers of Acidosis and Mortality in Cardiogenic Shock: Developing a Definition of Hemometabolic Shock

BACKGROUND

Acidosis and higher lactate predict worse outcomes in cardiogenic shock (CS) patients. We sought to determine whether overall acidosis severity on admission predicted in-hospital mortality in CS patients.

METHODS

This retrospective descriptive analysis included CS patients admitted to a single academic tertiary cardiac intensive care unit from 2007 to 2015. Admission arterial pH, base excess, and anion gap values were used to generate a Composite Acidosis Score (range 0-5, with a score ≥2 defining Severe Acidosis). Adjusted in-hospital mortality was analyzed using multivariable logistic regression.

RESULTS

We included 1,065 patients with median age of 68.9 (59.0, 77.2) years (36.4% females). Concomitant diagnoses included cardiac arrest in 38.1% and acute coronary syndrome in 59.1%. Severe Acidosis was present in 35.2%, and these patients had worse shock and more organ failure. In-hospital mortality occurred in 34.1% and was higher among patients with Severe Acidosis (54.9% vs. 22.4%, adjusted odds ratio [OR] 2.01, 95% CI 1.43-2.83, P < 0.001). Increasing Composite Acidosis Score was associated with higher in-hospital mortality (adjusted OR 1.25 per point, 95% CI 1.11-1.40, P < 0.001). Severe Acidosis was associated with higher hospital mortality at every level of shock severity and organ failure (all P < 0.05). Admission lactate level had equivalent discrimination for in-hospital mortality as the Composite Acidosis Score (0.69 vs. 0.66; P = 0.32 by De Long test).

CONCLUSION

Given its incremental association with higher in-hospital mortality among CS patients beyond shock severity and organ failure, we propose Severe Acidosis as a marker of hemometabolic shock. Lactate levels performed as well as a composite measure of acidosis for predicting mortality.

Management of Acute Aluminum Phosphide Poisoning: Has Anything Changed?

Due to its easy availability, rapid and severe toxicity, and no specific antidote, aluminum phosphide has emerged as a lethal toxin, commonly used for suicidal intent in agricultural communities. Despite various advances in medicine, this compound's toxicity is poorly understood, and it still has a very high case fatality rate with no definitive treatment options available. This review aims to understand the mechanism of toxicity, clinical toxidrome of acute aluminum phosphide poisoning, and the available therapeutic options, including recent advances. A literature review was performed searching PubMed, EMBASE Ovid, and Cochrane Library, using the following search items: ("aluminum phosphide poisoning" OR "aluminum phosphide poisoning toxicity" OR "aluminum phosphide ingestion") AND ("management" OR "therapy" OR "treatment"). Selected articles were discussed amongst all the authors to shape this review. High case fatality rate and lack of any specific antidote are persisting challenges. Therapeutic measures need to be implemented from all fronts - reducing easy access to the poison, developing less toxic alternatives for use as a pesticide, and more studies directed at developing an effective reversal agent for phosphine. The advent of promising agents like glucose-insulin-potassium infusion and lipid emulsion is a new ray of hope in the complete recovery in this fatal poisoning. The need of the hour is to find an agent that rapidly and effectively reverses aluminum phosphide's toxic effects. Large multicenter controlled trials are required to establish the role of glucose-insulin-potassium and lipid emulsion.

The gut-cardiovascular connection: new era for cardiovascular therapy

Our gut microbiome is constituted by trillions of microorganisms including bacteria, archaea and eukaryotic microbes. Nowadays, gut microbiome has been gradually recognized as a new organ system that systemically and biochemically interact with the host. Accumulating evidence suggests that the imbalanced gut microbiome contributes to the dysregulation of immune system and the disruption of cardiovascular homeostasis. Specific microbiome profiles and altered intestinal permeability are often observed in the pathophysiology of cardiovascular diseases. Gut-derived metabolites, toxins, peptides and immune cell-derived cytokines play pivotal roles in the induction of inflammation and the pathogenesis of dysfunction of heart and vasculature. Impaired crosstalk between gut microbiome and multiple organ systems, such as gut-vascular, heart-gut, gut-liver and brain-gut axes, are associated with higher cardiovascular risks. Medications and strategies that restore healthy gut microbiome might therefore represent novel therapeutic options to lower the incidence of cardiovascular and metabolic disorders.

Distance to Healthy Metabolic and Cardiovascular Dynamics From Fetal Heart Rate Scale-Dependent Features in Pregnant Sheep Model of Human Labor Predicts the Evolution of Acidemia and Cardiovascular Decompensation

The overarching goal of the present work is to contribute to the understanding of the relations between fetal heart rate (FHR) temporal dynamics and the well-being of the fetus, notably in terms of predicting the evolution of lactate, pH and cardiovascular decompensation (CVD). It makes uses of an established animal model of human labor, where 14 near-term ovine fetuses subjected to umbilical cord occlusions (UCO) were instrumented to permit regular intermittent measurements of metabolites lactate and base excess, pH, and continuous recording of electrocardiogram (ECG) and systemic arterial blood pressure (to identify CVD) during UCO. ECG-derived FHR was digitized at the sampling rate of 1,000 Hz and resampled to 4 Hz, as used in clinical routine. We focused on four FHR variability features which are tunable to temporal scales of FHR dynamics, robustly computable from FHR sampled at 4 Hz and within short-time sliding windows, hence permitting a time-dependent, or local, analysis of FHR which helps dealing with signal noise. Results show the sensitivity of the proposed features for early detection of CVD, correlation to metabolites and pH, useful for early acidosis detection and the importance of coarse time scales (2.5-8 s) which are not disturbed by the low FHR sampling rate. Further, we introduce the performance of an individualized self-referencing metric of the distance to healthy state, based on a combination of the four features. We demonstrate that this novel metric, applied to clinically available FHR temporal dynamics alone, accurately predicts the time occurrence of CVD which heralds a clinically significant degradation of the fetal health reserve to tolerate the trial of labor.

Managing the first 120 min of cardiogenic shock: from resuscitation to diagnosis

PURPOSE OF REVIEW

Cardiogenic shock continues to carry a high mortality, and recent randomized trials have not identified novel therapies that improve survival. Early optimization of patients with confirmed or suspected cardiogenic shock is crucial, as patients can quickly transition from a hemodynamic shock state to a treatment-resistant hemometabolic shock state, where accumulated metabolic derangements trigger a self-perpetuating cycle of worsening shock.

RECENT FINDINGS

We describe a structured ABCDE approach involving stabilization of the airway, breathing and circulation, followed by damage control and etiologic assessment. Respiratory failure is common and many cardiogenic shock patients require invasive mechanical ventilation. Norepinephrine is titrated to restore mean arterial pressure and dobutamine is titrated to restore cardiac output and organ perfusion. Echocardiography is essential to identify potential causes and characterize the phenotype of cardiogenic shock. Coronary angiography is usually indicated, particularly when acute myocardial ischemia is suspected, followed by culprit-vessel revascularization if indicated. An invasive hemodynamic assessment can clarify whether temporary mechanical circulatory support is necessary.

SUMMARY

Early stabilization of hemodynamics and end-organ function is necessary to achieve best outcomes in cardiogenic shock. Using a structured approach tailored to initial cardiogenic shock resuscitation may help to demonstrate benefit from novel therapies in the future.

Effect of sodium-chloride ion difference on pH regulation

BACKGROUND

In the Stewart approach, the difference between the cation and anion concentrations, especially between sodium, accounting for the majority of cations, and chloride, comprising the majority of anions, is an important factor in pH regulation. This study investigated the effect of sodium-chloride ion difference (SCD) on pH regulation comparing with those of PaCO₂ and lactate.

METHODS

Arterial blood gas samples measured at our pediatric intensive care unit of a tertiary children's hospital between January and June 2020 were included. Samples that met the following criteria were excluded: samples collected from patients taking potassium bromide and samples with lactate concentration of >25 mmol/L. From the eligible data, pH was chosen as the dependent variable and SCD, lactate, and PaCO₂ as independent variables, and then, a multiple regression analysis was performed.

RESULTS

In total, 5360 samples were included. Of these, five samples were excluded according to the exclusion criteria. Finally, 5355 samples were analyzed. As the variance inflation factors were <2.0 for all three variables, there was no multicollinearity. The following model was derived: pH = 7.384 + [0.97 × SCD (mEq/L) - 0.66 × PaCO₂ (mmHg) - 1.33 × Lac (mmol/L)] × 10^-2 (adjusted R-squared = 0.73; P value < 0.001). Based on the standardized partial regression coefficients (β), pH was affected in the order of PaCO₂ (β_PaCO2 = -0.95), SCD (β_SCD = 0.72), and lactate (β_lactate = -0.33).

CONCLUSIONS

The prevention of SCD reduction, together with respiratory and metabolic management, is important for pH regulation.

Effects of sodium bicarbonate infusion on mortality in medical-surgical ICU patients with metabolic acidosis-A single-center propensity score matched analysis

OBJECTIVE

Metabolic acidosis is associated with high mortality. Despite theoretical benefits of sodium-bicarbonate (SB), current evidence remains controversial. We investigated SB-related effects on outcomes in ICU patients with metabolic acidosis.

DESIGN

Retrospective analysis.

SETTING

Academic medical center.

PATIENTS OR PARTICIPANTS

971 ICU patients with metabolic acidosis defined as arterial pH<7.3 and CO2<45mmHg treated between 2012 and 2016. A propensity score (PS) was estimated using logistic regression. Patients were matched in pairs using the PS.

INTERVENTIONS

441 patients were treated with SB 8.4% (SB-group) and n=530 patients were not (control group).

MAIN VARIABLES OF INTEREST

Primary outcome was all-cause mortality at ICU-discharge. Average Treatment Effect (ATE), Average Treatment effect in Treated (ATT), and estimated relative survival effects at 20 days were computed.

RESULTS

In the full cohort, we observed considerable differences in pH, base excess, additional acidosis-related indices, and ICU mortality (controls 31% vs. SB-group 56%, p<.001) at baseline between the two groups. After PS-matching (n=174 in each group), no significant difference in ICU mortality was observed (controls 32% vs. SB-group 41%; p=.07). Odds ratios (OR) for ATE and ATT showed no association with ICU mortality (OR ATE: 1.08, 95%-CI 0.99-1.17; p=.08; OR ATT 1.09; 95%-CI 0.99-1.2; p=.09). Hazard ratios at 20-days (multivariable HR, matched sample n=348: 1.16, 95%-CI 0.86-1.56, p=.33) showed similar survival in the two study groups.

CONCLUSIONS

We did not observe effects of SB infusion on all-cause mortality in critically ill patients with metabolic acidosis.

Centhaquine Restores Renal Blood Flow and Protects Tissue Damage After Hemorrhagic Shock and Renal Ischemia

Background: Centhaquine (CQ) (Lyfaquin®) is in late stage clinical development as a safe and effective first-in-class resuscitative agent for hemorrhagic shock patients (NCT02408731, NCT04056065, and NCT04045327). Acute kidney injury (AKI) is known to be associated with hemorrhagic shock. Hence, effect of CQ on protection of kidneys from damage due to hemorrhagic shock was investigated. Methods: To assess effect of CQ on AKI in shock, we created a rat model with hemorrhagic shock and AKI. Renal arteries were clamped and de-clamped to induce AKI like ischemia/reperfusion model and hemorrhage was carried out by withdrawing blood for 30 min. Rats were resuscitated with CQ (0.02 mg/kg) for 10 min. MAP, heart rate (HR), and renal blood flow (RBF) were monitored for 120 min. Results: CQ produced a significant improvement in RBF compared to vehicle (p< 0.003) even though MAP and HR was similar in CQ and vehicle groups. Blood lactate level was lower (p = 0.0064) in CQ than vehicle at 120 min post-resuscitation. Histopathological analysis of tissues indicated greater renal damage in vehicle than CQ. Western blots showed higher HIF-1α (p = 0.0152) and lower NGAL (p = 0.01626) levels in CQ vs vehicle. Immunofluorescence in the kidney cortex and medulla showed significantly higher (p< 0.045) expression of HIF-1α and lower expression of Bax (p< 0.044) in CQ. Expression of PHD 3 (p< 0.0001) was higher, while the expression of Cytochrome C (p = 0.01429) was lower in the cortex of CQ than vehicle. Conclusion: Results show CQ (Lyfaquin®) increased renal blood flow, augmented hypoxia response, decreased tissue damage and apoptosis following hemorrhagic shock induced AKI, and may be explored to prevent/treat AKI. Translational Statement: Centhaquine (CQ) is safe for human use and currently in late stage clinical development as a first-in-class resuscitative agent to treat hemorrhagic shock. In the current study, we have explored a novel role of CQ in protection from hemorrhagic shock induced AKI, indicating its potential to treat/prevent AKI.

Targeted high volume hemofiltration could avoid extracorporeal membrane oxygenation in some patients with severe Hantavirus cardiopulmonary syndrome

Background

Hantavirus cardiopulmonary syndrome (HCPS) has a high lethality. Severe cases may be rescued by venoarterial extracorporeal membrane oxygenation (VA ECMO), alongside substantial complications. High volume hemofiltration (HVHF) is a depurative technique that provides homeostatic balance allowing hemodynamic stabilization in some critically ill patients.

Methods

We implemented HVHF before VA ECMO consideration in the last five severe HCPS patients requiring mechanical ventilation and vasoactive drugs admitted to our intensive care unit. Patients were considered HVHF‐responders if VA ECMO was avoided and HVHF‐nonresponders if VA ECMO support was needed despite HVHF. A targeted‐HVHF strategy compounded by aggressive hyperoncotic albumin, sodium bicarbonate, and calcium supplementation plus ultrafiltration to avoid fluid overload was implemented on three patients.

Results

Patients had maximum serum lactate of 8.8 (8.7–12.8) mmol/L and a lowest cardiac index of 1.8 (1.8–1.9) L/min/m². The first two required VA ECMO. They were connected later to HVHF, displayed progressive tachycardia and declining stroke volume. The opposite was true for HVHF‐responders who received targeted‐HVHF. All patients survived, but one of the VA ECMO patients suffered a vascular complication.

Conclusion

HVHF may contribute to support severe HCPS patients avoiding the need for VA ECMO in some. Early connection and targeted‐HVHF may increase the chance of success.

Fluid Resuscitation for Refractory Hypotension

Hypotension is a common occurrence, especially in anesthetized patients and in critical patients suffering from hypovolemia due to shock and sepsis. Hypotension can also occur in normovolemic animals, anesthetized or conscious, under conditions of vasodilation or decreased cardiac function. The main consequence of hypotension is decreased organ perfusion and tissue injury/dysfunction. In the human literature there is no consensus on what is the threshold value for hypotension, and ranges from < 80 to < 100 mmHg for systolic blood pressure and from < 50 to < 70 mmHg for mean arterial blood pressure have been referenced for intraoperative hypotension. In veterinary medicine, similar values are referenced, despite marked differences in normal arterial blood pressure between species and with respect to humans. Therapeutic intervention involves fluid therapy to normalize volemia and use of sympathomimetics to enhance cardiac function and regulate peripheral vascular resistance. Despite these therapeutic measures, there is a subset of patients that are seemingly refractory and exhibit persistent hypotension. This review covers the physiological aspects that govern arterial blood pressure control and blood flow to tissues/organs, the pathophysiological mechanisms involved in hypotension and refractory hypotension, and therapeutic considerations and expectations that include proper interpretation of cardiovascular parameters, fluid recommendations and therapy rates, use of sympathomimetics and vasopressors, and newer approaches derived from the human literature.

Acute kidney injury among salicylate intoxication hospitalisations in the United States

BACKGROUND

This study aimed to evaluate the risk factors and the association of acute kidney injury (AKI) with outcomes, and resource utilisation in patients hospitalised because of salicylate intoxication in the United States.

METHODS

Hospitalised patients with a primary diagnosis of salicylate intoxication from 2003 to 2014 were identified in the National Inpatient Sample (NIS) database. End-stage kidney disease patients were excluded. The occurrence of AKI was identified using hospital diagnosis code. Clinical characteristics, in-hospital treatment, outcomes and resource utilisation were compared between patients with and without AKI.

RESULTS

A total of 13 787 eligible hospital admissions were included in the analysis. AKI occurred in 1279 (9.3%) admissions. Older age, male sex, more recent year of hospitalisation, anaemia, hypertension, congestive heart failure, chronic kidney disease, volume depletion, sepsis and ventricular arrhythmia/cardiac arrest were significantly associated with increased risk of AKI, whereas Hispanic race was associated with decreased risk. AKI was significantly associated with increased risk of organ failure, and in-hospital mortality. In addition, the need for ventilation support, blood component transfusion, renal replacement therapy, length of hospital stay and hospitalisation cost were higher in AKI patients.

CONCLUSION

Approximately one tenth of salicylate intoxication patients developed AKI during hospitalisation. AKI was associated with higher morbidity, mortality and resource utilisations.

Risk Potential for Organ Dysfunction Associated With Sodium Bicarbonate Therapy in Critically Ill Patients With Hemodynamic Worsening

Background: The role of sodium bicarbonate therapy (SBT) remains controversial. This study aimed to investigate whether hemodynamic status before SBT contributed to the heterogeneous outcomes associated with SBT in acute critically ill patients. Methods: We obtained data from patients with metabolic acidosis from the Medical Information Mart for Intensive Care (MIMIC)-III database. Propensity score matching (PSM) was applied to match the SBT group with the control group. Logistic regression and Cox regression were used to analyze a composite of newly "developed or exacerbated organ dysfunction" (d/eOD) within 7 days of ICU admission and 28-day mortality associated with SBT for metabolic acidosis. Results: A total of 1,765 patients with metabolic acidosis were enrolled, and 332 pairs obtained by PSM were applied to the final analyses in the study. An increased incidence of newly d/eOD was observed in the SB group compared with the control group (54.8 vs. 44.6%, p < 0.01). Multivariable logistic regression indicated that the adjusted OR of SBT for this composite outcome was no longer significant [OR (95% CI): 1.39 (0.9, 1.85); p = 0.164]. This effect of SBT did not change with the quintiles stratified by pH. Interestingly, SBT was associated with an increased risk of the composite of newly d/eOD in the subgroup of patients with worsening hemodynamics before SBT [adjusted OR (95% CI): 3.6 (1.84, 7.22), p < 0.001]. Moreover, the risk potential for this composite of outcomes was significantly increased in patients characterized by both worsening [adjusted OR (95% CI): 2.91 (1.54, 5.47), p < 0.001] and unchanged hemodynamics [adjusted OR (95% CI): 1.94 (1.01, 3.72), p = 0.046] compared to patients with improved hemodynamics before SBT. Our study failed to demonstrate an association between SBT and 28-day mortality in acute critically ill patients with metabolic acidosis. Conclusions: Our findings did not demonstrate an association between SBT and outcomes in critically ill patients with metabolic acidosis. However, patients with either worsening or unchanged hemodynamic status in initial resuscitation had a significantly higher risk potential of newly d/eOD subsequent to SBT.

Blood Lactate And Lactate Clearance: Refined Biomarker And Prognostic Marker In Burn Resuscitation

Adequate resuscitation of acute burn patients is important to ensure end organ perfusion and oxygenation. The ideal marker to the endpoint of burn resuscitation is still not established. We aimed to evaluate the role of blood lactate and lactate clearance in burn resuscitation and their association with mortality and sepsis in burn patients. The retrospective study included patients (18-50 years) with thermal and scald burns with total body surface area of 30% to 60% over a period of 9 months who had achieved target urine output of at least 0.5ml/kg/hr within 24 hours of resuscitation. Patients were divided based on their admission blood lactate levels (Group A < 2 mmol/L and Group B > 2 mmol/L). Group B was further subdivided into Group B1 in whom blood lactate levels reached less than 2 mmol/L within 24 hours of burn resuscitation and Group B2 in whom it did not. Total patients included were 203. Mortality (M) and sepsis (S) rates in subgroup B2 were higher (M=57.9%; S=43.5%) and rates in subgroup B1 (M=25.8%; S=27.4%) were comparable to Group A (M=27.8%; S=26.4%). Persistent lactic acidosis at 24 hours was independently associated with significantly increased mortality and sepsis. Our data suggests a correlation of blood lactate levels and lactate clearance within 24 hours of admission with mortality and sepsis related to burn injury.

Pathophysiology and clinical consequences of arterial blood gases and pH after cardiac arrest

Post cardiac arrest syndrome is associated with high morbidity and mortality, which is related not only to a poor neurological outcome but also to respiratory and cardiovascular dysfunctions. The control of gas exchange, and in particular oxygenation and carbon dioxide levels, is fundamental in mechanically ventilated patients after resuscitation, as arterial blood gases derangement might have important effects on the cerebral blood flow and systemic physiology.

In particular, the pathophysiological role of carbon dioxide (CO₂) levels is strongly underestimated, as its alterations quickly affect also the changes of intracellular pH, and consequently influence metabolic energy and oxygen demand. Hypo/hypercapnia, as well as mechanical ventilation during and after resuscitation, can affect CO₂ levels and trigger a dangerous pathophysiological vicious circle related to the relationship between pH, cellular demand, and catecholamine levels. The developing hypocapnia can nullify the beneficial effects of the hypothermia. The aim of this review was to describe the pathophysiology and clinical consequences of arterial blood gases and pH after cardiac arrest.

According to our findings, the optimal ventilator strategies in post cardiac arrest patients are not fully understood, and oxygen and carbon dioxide targets should take in consideration a complex pattern of pathophysiological factors. Further studies are warranted to define the optimal settings of mechanical ventilation in patients after cardiac arrest.

Intravenous thiamine for septic shock: A meta-analysis of randomized controlled trials

INTRODUCTION

The efficacy of intravenous thiamine to treat septic shock remains controversial. We conduct a systematic review and meta-analysis to explore the impact of intravenous thiamine on treatment efficacy of septic shock.

METHODS

We have searched PubMed, EMbase, Web of science, EBSCO, and Cochrane library databases through June 2020 and included randomized controlled trials (RCTs) assessing the effect of intravenous thiamine on septic shock. This meta-analysis was performed using the random-effect model.

RESULTS

Four RCTs were included in the meta-analysis. Overall, compared with control group in patients with septic shock, intravenous thiamine revealed no substantial impact on mortality (odd ratio [OR] = 0.87; 95% confidence interval [CI) = 0.62 to 1.21; P = 0.40), lactate change (standard mean difference [SMD] = 0.04; 95% CI = -0.28 to 0.35; P = 0.82), Sequential Organ Failure Assessment (SOFA) change (SMD = 0.02; 95% CI = -0.18 to 0.21; P = 0.87), intensive care unit (ICU) stay (SMD = -0.02; 95% CI = -0.33 to 0.30; P = 0.90) or renal replacement therapy (OR = 0.47; 95% CI = 0.07 to 3.15; P = 0.43).

CONCLUSIONS

Intravenous thiamine showed no benefit over placebo in treating patients with septic shock.

Resuscitation After Hemorrhagic Shock in the Microcirculation: Targeting Optimal Oxygen Delivery in the Design of Artificial Blood Substitutes

Microcirculatory preservation is essential for patient recovery from hemorrhagic shock. In hemorrhagic shock, microcirculatory flow and pressure are greatly reduced, creating an oxygen debt that may eventually become irreversible. During shock, tissues become hypoxic, cellular respiration turns to anaerobic metabolism, and the microcirculation rapidly begins to fail. This condition requires immediate fluid resuscitation to promote tissue reperfusion. The choice of fluid for resuscitation is whole blood; however, this may not be readily available and, on a larger scale, may be globally insufficient. Thus, extensive research on viable alternatives to blood has been undertaken in an effort to develop a clinically deployable blood substitute. This has not, as of yet, achieved fruition, in part due to an incomplete understanding of the complexities of the function of blood in the microcirculation. Hemodynamic resuscitation is acknowledged to be contingent on a number of factors other than volume expansion. The circulation of whole blood is carefully regulated to optimize oxygen delivery to the tissues via shear stress modulation through blood viscosity, inherent oxygen-carrying capacity, cell-free layer variation, and myogenic response, among other variables. Although plasma expanders can address a number of these issues, hemoglobin-based oxygen carriers (HBOCs) introduce a method of replenishing the intrinsic oxygen-carrying capacity of blood. There continue to be a number of issues related to HBOCs, but recent advances in the next-generation HBOCs show promise in the preservation of microcirculatory function and limiting toxicities. The development of HBOCs is now focused on viscosity and the degree of microvascular shear stress achieved in order to optimize vasoactive and oxygen delivery responses by leveraging the restoration and maintenance of physiological responses to blood flow in the microcirculation. Blood substitutes with higher viscous properties tend to improve oxygen delivery compared to those with lower viscosities. This review details current concepts in blood substitutes, particularly as they relate to trauma/hemorrhagic shock, with a specific focus on their complex interactions in the microcirculation.

Hemodynamic Instability and Abnormal Vasopressor Responsiveness in the Setting of Severe Metabolic Acidosis Treated With Adapted Alkalinization and Continuous Renal Replacement Therapy in the Emergency Department

BACKGROUND

Whereas laboratory data and clinical experience suggest that metabolic acidosis deleteriously affects certain cardiovascular functions and may contribute to hemodynamic compromise, treatment of acidemia itself with alkalinization therapy, predominantly in the form of bolus dosing of intravenous sodium bicarbonate, has not been shown to improve hemodynamics or patient-oriented outcomes in clinical trials. Detailed examination of the biochemical effects of standard sodium bicarbonate administration reveals a possible explanation: ionized serum hypocalcemia, serum hypercarbia, and a paradoxical decrease in intracellular pH occur when bicarbonate is given alone and rapidly, without adjustment in minute ventilation or calcium supplementation. "Adapted alkalinization" treatment countering these side effects through hyperventilation, calcium supplementation, and slower sodium bicarbonate infusion has been studied in animals, but not yet described in humans.

CASE REPORT

We report a case of successful treatment of severe hemodynamic instability and vasopressor hyporesponsiveness in the setting of profound metabolic acidosis with such an adapted alkalinization approach, plus short-term continuous renal replacement therapy, in a critically ill patient, all performed in the emergency department. WHY SHOULD AN EMERGENCY PHYSICIAN BE AWARE OF THIS?: Emergency physicians encounter patients with severe metabolic acidosis, shock, and hemodynamic instability despite vasopressor agents. Adapted alkalinization therapy with sodium bicarbonate, hyperventilation, and calcium administration may promote hemodynamic stability in such patients and allow for successful treatment of the underlying disease process.

Is It the pH That Matters? Challenging the Pathophysiology of Acidemia in a Case of Severe Hypercapnia Secondary to Intraoperative CO2 Insufflation

Background

Acidemia has been long thought to lead to hemodynamic compromise. While some literature to date challenges this idea, there is no consensus on this topic.

Case Summary

To our knowledge, this is the most severe case of hypercapnia and acidosis due to carbon dioxide (CO₂) insufflation during laparoscopy reported in the literature. Remarkably, this patient remained hemodynamically normal despite having a blood pH below 6.81. This prompts a wider discussion about the effects of blood pH on human physiology. Most patients who present acidotic are critically ill and have confounding underlying metabolic or respiratory pathophysiology driving their illness. In this case, the patient experienced no respiratory insult leading to an increase in blood CO₂ but rather had CO₂ iatrogenically introduced into the circulatory system, effectively detaching the deleterious effects of CO₂ from the respiratory pathologies that so often cause its accumulation.

Conclusion

This raises the question, in patients with severe acidosis and hemodynamic compromise, is acidosis a symptom of the underlying process, or is the acidosis itself causing harm?

Electrocardiographic findings of methanol toxicity: a cross-sectional study of 356 cases in Iran

BACKGROUND

Methanol is widely used in industry; however, methanol poisoning is not common. In this regard, a number of outbreaks have been recently reported due to inappropriate processing of alcoholic beverages. Shiraz, a city located in the southern part of Iran, faced one of such outbreaks in 2020 during COVID-19 pandemic. There is no sufficient literature on the electrocardiographic findings in methanol toxicity. This study aimed to address this gap in the literature.

METHOD

A total of 356 cases with methanol toxicity referred to Shiraz University of Medical Science Tertiary Hospitals (Faghihi and Namazi) in March and April, 2020. The clinical findings of blindness and impaired level of consciousness, lab data such as arterial blood gas, electrolytes, and creatinine, and the most common findings from ECGs were collected.

RESULTS

The most common ECG findings were J point elevation (68.8%), presence of U wave (59.2%), QTc prolongation (53.2% in males and 28.6% in females), and fragmented QRS (33.7%). An outstanding finding in this study was the presence of myocardial infarction in 5.3% of the cases. This finding, to the best of our knowledge, has only been reported in a few case reports. Brugada pattern (8.1%) and Osborn wave (3.7%) were the other interesting findings. In multivariate analysis, when confounding factors were adjusted, myocardial infarction, atrioventricular conduction disturbances, sinus tachycardia, and the prolonged QTC > 500 msecond were four independent factors correlated with methanol toxicity severity measured with arterial blood PH on arterial blood gas measurements, with odds ratios of 12.82, 4.46, 2.32 and 3.15 (P < 0.05 for all), respectively.

CONCLUSION

Electrocardiographic variations during methanol intoxication are remarkable and well-correlated with poisoning severity. Myocardial infarction was an egregious and yet a common concerning finding in this sample, which need to be ruled out in methanol toxicity.

Angiotensin II Infusion for Shock: A Multicenter Study of Postmarketing Use

BACKGROUND

Vasodilatory shock refractory to catecholamine vasopressors and arginine vasopressin is highly morbid and responsible for significant mortality. Synthetic angiotensin II is a potent vasoconstrictor that may be suitable for use in these patients.

RESEARCH QUESTION

What is the safety and effectiveness of angiotensin II and what variables are associated with a favorable hemodynamic response?

STUDY DESIGN AND METHODS

We performed a multicenter, retrospective study at five tertiary medical centers in the United States. The primary end point of hemodynamic responsiveness to angiotensin II was defined as attainment of mean arterial pressure (MAP) of ≥ 65 mm Hg with a stable or reduced total vasopressor dosage 3 h after drug initiation.

RESULTS

Of 270 included patients, 181 (67%) demonstrated hemodynamic responsiveness to angiotensin II. Responders showed a greater increase in MAP (+10.3 mm Hg vs +1.6 mm Hg, P < .001) and reduction in vasopressor dosage (-0.20 μg/kg/min vs +0.04 μg/kg/min; P < .001) compared with nonresponders at 3 h. Variables associated with favorable hemodynamic response included lower lactate concentration (OR 1.11; 95% CI, 1.05-1.17, P < .001) and receipt of vasopressin (OR, 6.05; 95% CI, 1.98-18.6; P = .002). In severity-adjusted multivariate analysis, hemodynamic responsiveness to angiotensin II was associated with reduced likelihood of 30-day mortality (hazard ratio, 0.50; 95% CI, 0.35-0.71; P < .001). Arrhythmias occurred in 28 patients (10%) and VTE was identified in 4 patients.

INTERPRETATION

In postmarketing use for vasopressor-refractory shock, 67% of angiotensin II recipients demonstrated a favorable hemodynamic response. Patients with lower lactate concentrations and those receiving vasopressin were more likely to respond to angiotensin II. Patients who responded to angiotensin II experienced reduced mortality.