Membrane polarity: a target for myocardial protection and reduced inflammation in adult and pediatric cardiothoracic surgery

Short-term outcome of adenosine-lidocaine-magnesium polarizing cardioplegia in humans

OBJECTIVES

Hyperkalaemic depolarized myocardial arrest is the cornerstone of myocardial protection, although some potassium-related cytotoxicity has been demonstrated. Polarized arrest has gained interest because of a reported better myocardial protection in preclinical studies. The goal of this study was to analyse the quality of myocardial protection and hospital outcome after normokalaemic adenosine-lidocaine-magnesium (ALM) blood polarizing cardioplegia, compared to hyperkalaemic blood Buckberg depolarizing cardioplegia, in elective routine adult cardiac surgery.

METHODS

One thousand consecutive elective adult cardiac patients [627 undergoing ALM-polarizing cardioplegia (ALM-POL) vs 373 Buckberg depolarized cardioplegia (BUCK-DEPOL)] who were operated on were analysed. Perioperative leakage of high-sensitivity troponin I (Hs-TnI), peripheral lactate, inotropic and vasoactive daily requirement [maximal vasoactive inotropic score (VISMAX)], hospital mortality and morbidity were collected and compared in the overall population and in the propensity score (PS) matched population (206 pairs).

RESULTS

A significantly lower leakage of Hs-TnI during hospitalization was detected in patients receiving ALM-POL versus those receiving BUCK-DEPOL (group time P < 0.001 for overall population and PS matched pairs). The maximum value of postoperative Hs-TnI was also lower after ALM-POL (P < 0.001 in both cohorts), and spontaneous recovery of sinus rhythm at aortic declamping was higher (P < 0.001 in favour of ALM-POL). Maximal VISMAX during hospitalization was significantly higher after BUCK-DEPOL in both cohorts (P = 0.019 for overall population; P = 0.031 for PS matched population), with significantly higher VISMAX on the day of surgery in BUCK-DEPOL PS matched patients (P = 0.042). No other significant differences in hospital morbidity and mortality were found.

CONCLUSIONS

Despite comparable short-term clinical outcomes, ALM-POL cardioplegia proved superior in terms of quality of myocardial protection compared to BUCK-DEPOL cardioplegia in elective routine adult cardiac surgery.

Cardioplegia between Evolution and Revolution: From Depolarized to Polarized Cardiac Arrest in Adult Cardiac Surgery

Despite current advances in perioperative care, intraoperative myocardial protection during cardiac surgery has not kept the same pace. High potassium cardioplegic solutions were introduced in the 1950s, and in the early 1960s they were soon recognized as harmful. Since that time, surgeons have minimized many of the adverse effects by lowering the temperature of the heart, lowering K⁺ concentration, reducing contact K⁺ time, changing the vehicle from a crystalloid solution to whole-blood, adding many pharmacological protectants and modifying reperfusion conditions. Despite these attempts, high potassium remains a suboptimalway to arrest the heart. We briefly review the historical advances and failures of finding alternatives to high potassium, the drawbacks of a prolonged depolarized membrane, altered Ca²⁺ intracellular circuits and heterogeneity in atrial-ventricular K⁺ repolarization during reanimation. Many of these untoward effects may be alleviated by a polarized membrane, and we will discuss the basic science and clinical experience from a number of institutions trialling different alternatives, and our institution with a non-depolarizing adenosine, lidocaine and magnesium (ALM) cardioplegia. The future of polarized arrest is an exciting one and may play an important role in treating the next generation of patients who are older, and sicker with multiple comorbidities and require more complex operations with prolonged cross-clamping times.

Therapeutic cardiac arrest as an adjunct to resuscitative endovascular balloon occlusion of the aorta: Bridging the gap from fatal hemorrhage to definitive surgical control in swine

BACKGROUND

Uncontrolled hemorrhage is the leading cause of potentially survivable combat casualty mortality, with 86.5% of cases resulting from noncompressible torso hemorrhage. Resuscitative endovascular balloon occlusion of the aorta (REBOA) is a minimally invasive technique used to stabilize patients with noncompressible torso hemorrhage; however, its application can take an average of 8 minutes to place. One therapeutic capable of bridging this gap is adenosine-lidocaine-magnesium (ALM), which at high doses induces a reversible cardioplegia. We hypothesize by using ALM as an adjunct to REBOA, the ALM-induced cardiac arrest will temporarily halt exsanguination and reduce blood loss, allowing for REBOA placement and control of bleeding.

METHODS

Male Yorkshire swine (60-80 kg) were randomly assigned to REBOA only or ALM-REBOA (n = 8/group). At baseline, uncontrolled hemorrhage was induced via a 1.5-cm right femoral arteriotomy, and hemorrhaged blood was quantified. One minute after injury (S1), ALM was administered, and 7 minutes later (T0), zone 1 REBOA inflation occurred. If cardiac arrest ensued, cardiac function either recovered spontaneously or advanced life support was initiated. At T30, surgical hemostasis was obtained, and REBOA was deflated. Animals were resuscitated until they were humanely euthanized at T90.

RESULTS

During field care phase, heart rate and end-tidal CO2 of the ALM-REBOA group were significantly lower than the REBOA only group. While mean arterial pressure significantly decreased from baseline, no significant differences between groups were observed throughout the field care phase. There was no significant difference in survival between the two groups (ALM-REBOA = 89% vs. REBOA only = 100%). Total blood loss was significantly decreased in the ALM-REBOA group (REBOA only = 24.32 ± 1.89 mL/kg vs. ALM-REBOA = 17.75 ± 2.04 mL/kg, p = 0.0499).

CONCLUSION

Adenosine-lidocaine-magnesium is a novel therapeutic, which, when used with REBOA, can significantly decrease the amount of blood loss at initial presentation, without compromising survival. This study provides proof of concept for ALM and its ability to bridge the gap between patient presentation and REBOA placement.

Living in a Hostile World: Inflammation, New Drug Development, and Coronavirus

We present a brief history of the immune response and show that Metchnikoff's theory of inflammation and phagocytotic defense was largely ignored in the 20th century. For decades, the immune response was believed to be triggered centrally, until Lafferty and Cunningham proposed the initiating signal came from the tissues. This shift opened the way for Janeway's pattern recognition receptor theory, and Matzinger's danger model. All models failed to appreciate that without inflammation, there can be no immune response. The situation changed in the 1990s when cytokine biology was rapidly advancing, and the immune system's role expanded from host defense, to the maintenance of host health. An inflammatory environment, produced by immune cells themselves, was now recognized as mandatory for their attack, removal and repair functions after an infection or injury. We explore the cellular programs of the immune response, and the role played by cytokines and other mediators to tailor the right response, at the right time. Normally, the immune response is robust, self-limiting and restorative. However, when the antigen load or trauma exceeds the body's internal tolerances, as witnessed in some COVID-19 patients, excessive inflammation can lead to increased sympathetic outflows, cardiac dysfunction, coagulopathy, endothelial and metabolic dysfunction, multiple organ failure and death. Currently, there are few drug therapies to reduce excessive inflammation and immune dysfunction. We have been developing an intravenous (IV) fluid therapy comprising adenosine, lidocaine and Mg2+ (ALM) that confers a survival advantage by preventing excessive inflammation initiated by sepsis, endotoxemia and sterile trauma. The multi-pronged protection appears to be unique and may provide a tool to examine the intersection points in the immune response to infection or injury, and possible ways to prevent secondary tissue damage, such as that reported in patients with COVID-19.

Effect of Del Nido cardioplegia on ventricular arrhythmias after cardiovascular surgery

BACKGROUND

Del Nido cardioplegia (DNC) has been proven safe and effective in pediatric patients. However, the use of DNC in adult undergoing cardiovascular surgery lacks support with substantial evidence. This study aimed to evaluate the efficacy of DNC as a cardioplegia of prophylaxis to ventricular arrhythmias associated to cardiovascular surgery in adult patients.

METHODS

This study recruited nine hundred fifty-four patients who underwent cardiopulmonary bypass surgeries in Nanjing Hospital affiliated to Nanjing Medical University between January 2019 and December 2019. Among 954 patients, 324 patients were treated with DNC (DNC group), and 630 patients were treated with St. Thomas cardioplegia (STH group). The incidence of postoperative arrhythmia as well as other cardiovascular events relavant to the surgery were investigated in both groups.

RESULTS

In DNC group, the incidence of postoperative ventricular arrhythmias was lower (12.4% vs. 17.4%, P = 0.040), and the length of ICU stay was shorter (1.97 ± 1.49 vs. 2.26 ± 1.46, P = 0.004). Multivariate logistic regression demonstrated that the use of DNC helped to reduce the incidence of postoperative ventricular arrhythmias (adjusted odds ratio 0.475, 95% CI 0.266-0.825, P = 0.010). The propensity score-based analysis and subgroup analysis indicated that DNC has the same protecting effects towards myocardial in all kinds of cardiopulmonary bypass surgeries.

CONCLUSIONS

Del Nido cardioplegia may potentially reduce the incidence of postoperative ventricular arrhythmias, shorten the length of ICU stay and improve the overall outcome of the patients undergoing cardiovascular surgery.

Prehospital adenosine, lidocaine, and magnesium has inferior survival compared with tactical combat casualty care resuscitation in a porcine model of prolonged hemorrhagic shock

BACKGROUND

Adenosine, lidocaine, and magnesium (ALM) is a cardioplegic agent shown to improve survival by improving cardiac function, tissue perfusion, and coagulopathy in animal models of shock. We hypothesized prehospital ALM treatment in hemorrhagic shock would improve survival compared to current Tactical Combat Casualty Care (TCCC) resuscitation beyond the golden hour.

METHODS

Swine were randomized to: (1) TCCC, (2) 2 mL·kg vehicle control (VC), (3) 2 mL·kg ALM + drip, (4) 4 mL·kg ALM + drip, 5) 4 mL·kg ALM + delayed drip at 0.5 mL·kg·h, 6) 4 mL/kg VC, 7) 4 mL·kg ALM for 15 minutes + delayed drip at 3 mL·kg·h. Animals underwent pressure controlled hemorrhage to mean arterial pressure (MAP) of 30 mm Hg (S = 0). Treatment was administered at T = 0. After 120 minutes of simulated prehospital care (T = 120) blood product resuscitation commenced. Physiologic variables were recorded and laboratories were drawn at specified time points.

RESULTS

Tactical Combat Casualty Care demonstrated superior survival to all other agents. The VC and ALM groups had lower MAPs and systolic blood pressures compared with TCCC. Except for the VC groups, lactate levels remained similar with correction of base deficit after prehospital resuscitation in all groups. Kidney function and liver function remained comparable across all groups. Compared with baseline values, TCCC demonstrated significant hypocoagulability.

CONCLUSION

Adenosine, lidocaine, and magnesium, as administered in this study, are inferior to current Hextend-based resuscitation for survival from prolonged hemorrhagic shock in this model. In survivors, ALM groups had lower systolic blood pressures and MAPs, but provided a protective effect on coagulopathy as compared to TCCC. Adenosine, lidocaine, and magnesium do not appear to be a suitable low volume replacement to current TCCC resuscitation. The reduced coagulopathy compared to TCCC warrants future studies of ALM, perhaps as a therapeutic adjunct.

Pheretima aspergillum extract attenuates high-KCl-induced mitochondrial injury and pro-fibrotic events in cardiomyoblast cells

Hyperkalemia is often associated with cardiac dysfunction. In this study an earthworm extract (dilong) was prepared from dried Pheretima aspergillum powder and its effect against high-KCl challenge was determined in H9c2 cardiomyoblast cells. H9c2 cells pre-treated with dilong (31.25, 62.5, 125, and 250 mg/mL) for 24 hours, where challenged with different doses of KCl treatment for 3 hours to determine the protective mechanisms of dilong against cardiac fibrosis. High-KCl administration induced mitochondrial injury and elevated the levels of pro-apoptotic proteins. The mediators of fibrosis such as ERK, uPA, SP1, and CTGF were also found to be upregulated in high-KCl condition. However, dilong treatment enhanced IGF1R/PI3k/Akt activation which is associated with cell survival. In addition, dilong also reversed high-KCl induced cardiac fibrosis related events in H9c2 cells and displayed a strong cardio-protective effect. Therefore, dilong is a potential agent to overcome cardiac events associated with high-KCl toxicity.

The CNS theory of osteoarthritis: Opportunities beyond the joint

Osteoarthritis (OA) is a leading cause of global disability that affects more than half of the population over 65. It is not a single disease but a progressive, inflammatory- and immune-altering multi-disease that affects the whole joint. OA has many risk factors including age, obesity, gender, lifestyle, joint morphology, metabolic dysfunction and genetic disposition. A major stumbling block in treating clinical OA has been the inability to detect its early onset and disease progression. This gap in understanding may arise from our failure to recognize that the OA patient exhibits a vulnerability to dysregulation of central feedback circuits that control sympathetic tone, inflammation, circadian rhythms (central and peripheral clocks), gut microbiome, metabolic redox and whole joint pathology. Early detection of OA and slowing its progression may come from discoveries outside the joint targeting these potentially modifiable upstream targets. We argue that future treatments may benefit from moving from a knee-centric viewpoint to a more systems-based, whole-body approach. The challenge, however, will be to better characterize these key circuits and apply this knowledge to develop new therapies and interventions.

Mechanisms of early trauma-induced coagulopathy: The clot thickens or not?

Traumatic-induced coagulopathy (TIC) is a hemostatic disorder that is associated with significant bleeding, transfusion requirements, morbidity and mortality. A disorder similar or analogous to TIC was reported around 70 years ago in patients with shock, hemorrhage, burns, cardiac arrest or undergoing major surgery, and the condition was referred to as a "severe bleeding tendency," "defibrination syndrome," "consumptive disorder," and later by surgeons treating US Vietnam combat casualties as a "diffuse oozing coagulopathy." In 1982, Moore's group termed it the "bloody vicious cycle," others "the lethal triad," and in 2003 Brohi and colleagues introduced "acute traumatic coagulopathy" (ATC). Since that time, early TIC has been cloaked in many names and acronyms, including a "fibrinolytic form of disseminated intravascular coagulopathy (DIC)." A global consensus on naming is urgently required to avoid confusion. In our view, TIC is a dynamic entity that evolves over time and no single hypothesis adequately explains the different manifestations of the coagulopathy. However, early TIC is not DIC because an increased thrombin-generating potential in vitro does not imply a clinically relevant thrombotic state in vivo as early TIC is characterized by excessive bleeding, not thrombosis. DIC with its diffuse anatomopathologic fibrin deposition appears to be a latter phase progression of TIC associated with unchecked inflammation and multiple organ dysfunction.

del Nido cardioplegia in adult cardiac surgery - scopes and concerns

The convenience offered by a single-dose cardioplegia strategy is the avoidance of interruption of the flow of surgery and, more importantly, a significant reduction in the cross-clamp time. del Nido cardioplegia is an extracellular cardioplegic solution which serves these purposes and has been used successfully in pediatric cardiac surgery. The subsequent extrapolation of its use in adult cardiac surgery has returned encouraging results, as evidenced by recent literature. The use of del Nido cardioplegia in adults has been reported to shorten the cross-clamp time, cardiopulmonary bypass time and overall operating time. Intraoperative peak glucose value and insulin requirement have also been reported to be lower with del Nido cardioplegia, which can have prognostic significance. There have been reports of lesser incidence of atrial fibrillation and the number of defibrillations required with use of this technique. However, some unique concerns still remain. The lack of prospective randomized trials, the trend of elevation in CKMB (as reported by one study) and the need for a protocol-based approach to its use in adults are to be given due consideration while adopting its use in adults. This review attempts to have an overview on del Nido cardioplegia, its advantages, the recent studies comparing it with conventional cardioplegia techniques and the potential areas of concern with its use in adult cardiac surgery.

Addressing the Global Burden of Trauma in Major Surgery

Despite a technically perfect procedure, surgical stress can determine the success or failure of an operation. Surgical trauma is often referred to as the "neglected step-child" of global health in terms of patient numbers, mortality, morbidity, and costs. A staggering 234 million major surgeries are performed every year, and depending upon country and institution, up to 4% of patients will die before leaving hospital, up to 15% will have serious post-operative morbidity, and 5-15% will be readmitted within 30 days. These percentages equate to around 1000 deaths and 4000 major complications every hour, and it has been estimated that 50% may be preventable. New frontline drugs are urgently required to make major surgery safer for the patient and more predictable for the surgeon. We review the basic physiology of the stress response from neuroendocrine to genomic systems, and discuss the paucity of clinical data supporting the use of statins, beta-adrenergic blockers and calcium-channel blockers. Since cardiac-related complications are the most common, particularly in the elderly, a key strategy would be to improve ventricular-arterial coupling to safeguard the endothelium and maintain tissue oxygenation. Reduced O2 supply is associated with glycocalyx shedding, decreased endothelial barrier function, fluid leakage, inflammation, and coagulopathy. A healthy endothelium may prevent these "secondary hit" complications, including possibly immunosuppression. Thus, the four pillars of whole body resynchronization during surgical trauma, and targets for new therapies, are: (1) the CNS, (2) the heart, (3) arterial supply and venous return functions, and (4) the endothelium. This is termed the Central-Cardio-Vascular-Endothelium (CCVE) coupling hypothesis. Since similar sterile injury cascades exist in critical illness, accidental trauma, hemorrhage, cardiac arrest, infection and burns, new drugs that improve CCVE coupling may find wide utility in civilian and military medicine.

Correction of acute traumatic coagulopathy with small-volume 7.5% NaCl adenosine, lidocaine, and Mg2+ occurs within 5 minutes: a ROTEM analysis

BACKGROUND

Acute traumatic coagulopathy is a major contributor to mortality and morbidity following hemorrhagic shock. Our aim was to examine the effect of small-volume 7.5% NaCl with adenosine, lidocaine, and Mg (ALM) resuscitation on the timing of correction of coagulopathy in the rat model of severe hemorrhagic shock using ROTEM.

METHODS

Male rats (300-450 g, n = 64) were randomly assigned to (1) baseline, (2) sham, (3) bleed, (4) shock, (5) 7.5% NaCl for 5 minutes, (6) 7.5% NaCl with ALM for 5 minutes, (7) 7.5% NaCl for 60 minutes, or (8) 7.5% NaCl with ALM for 60 minutes (all n = 8). For resuscitation, 0.3-mL intravenous bolus of 7.5% NaCl was administered with and without ALM (n = 8 each group). Hemodynamics and coagulopathy were assessed.

RESULTS

After hemorrhage, prothrombin time (PT) and activated partial thromboplastin time (aPTT) increased approximately four to six times, and ROTEM indicated hypocoagulopathy. After 60-minute shock, no sustainable clots could form. 7.5% NaCl increased mean arterial pressure (MAP) to 46 ± 2 mm Hg at 5 minutes and generated a weak clot in EXTEM with hyperfibrinolysis in all tests. At 60 minutes, 7.5% NaCl failed to sustain MAP (43 ± 5 mm Hg) and generate a viable clot. In direct contrast, 7.5% NaCl with ALM at 5 minutes resuscitated MAP to 64 ± 3 mm Hg, corrected PT and aPTT, and generated fully formed EXTEM and FIBTEM clots. At 60 minutes, MAP was 69 ± 5 mm Hg, PT and aPTT were fully corrected, and α angle, clot amplitudes (A10, A30), as well as clot firmness and elasticity were not significantly different from baseline. ALM clot lysis at 60 minutes was significantly less than bleed, shock, or 7.5% NaCl, indicating protection against hyperfibrinolysis.

CONCLUSION

Small-volume 7.5% NaCl failed to resuscitate and correct coagulopathy. In contrast, 7.5% NaCl with ALM resuscitated MAP and corrected coagulopathy at 5 minutes, with further improvements at 60 minutes in clot kinetics, propagation, and firmness. ALM fully reversed hyperfibrinolysis to baseline. The possible mechanisms are discussed.

Adenosine, lidocaine and Mg2+ improves cardiac and pulmonary function, induces reversible hypotension and exerts anti-inflammatory effects in an endotoxemic porcine model

Introduction

The combination of Adenosine (A), lidocaine (L) and Mg²⁺ (M) (ALM) has demonstrated cardioprotective and resuscitative properties in models of cardiac arrest and hemorrhagic shock. This study evaluates whether ALM also demonstrates organ protective properties in an endotoxemic porcine model.

Methods

Pigs (37 to 42 kg) were randomized into: 1) Control (n = 8) or 2) ALM (n = 8) followed by lipopolysaccharide infusion (1 μg∙kg^-1∙h^-1) for five hours. ALM treatment consisted of 1) a high dose bolus (A (0.82 mg/kg), L (1.76 mg/kg), M (0.92 mg/kg)), 2) one hour continuous infusion (A (300 μg∙kg^-1 ∙min^-1), L (600 μg∙kg^-1 ∙min^-1), M (336 μg∙kg^-1 ∙min^-1)) and three hours at a lower dose (A (240∙kg^-1∙min^-1), L (480 μg∙kg^-1∙min^-1), M (268 μg∙kg^-1 ∙min^-1)); controls received normal saline. Hemodynamic, cardiac, pulmonary, metabolic and renal functions were evaluated.

Results

ALM lowered mean arterial pressure (Mean value during infusion period: ALM: 47 (95% confidence interval (CI): 44 to 50) mmHg versus control: 79 (95% CI: 75 to 85) mmHg, P <0.0001). After cessation of ALM, mean arterial pressure immediately increased (end of study: ALM: 88 (95% CI: 81 to 96) mmHg versus control: 86 (95% CI: 79 to 94) mmHg, P = 0.72). Whole body oxygen consumption was significantly reduced during ALM infusion (ALM: 205 (95% CI: 192 to 217) ml oxygen/min versus control: 231 (95% CI: 219 to 243) ml oxygen/min, P = 0.016). ALM treatment reduced pulmonary injury evaluated by PaO₂/FiO₂ ratio (ALM: 388 (95% CI: 349 to 427) versus control: 260 (95% CI: 221 to 299), P = 0.0005). ALM infusion led to an increase in heart rate while preserving preload recruitable stroke work. Creatinine clearance was significantly lower during ALM infusion but reversed after cessation of infusion. ALM reduced tumor necrosis factor-α peak levels (ALM 7121 (95% CI: 5069 to 10004) pg/ml versus control 11596 (95% CI: 9083 to 14805) pg/ml, P = 0.02).

Conclusion

ALM infusion induces a reversible hypotensive and hypometabolic state, attenuates tumor necrosis factor-α levels and improves cardiac and pulmonary function, and led to a transient drop in renal function that was reversed after the treatment was stopped.

Adenosine, lidocaine and Mg2+ (ALM) induces a reversible hypotensive state, reduces lung edema and prevents coagulopathy in the rat model of polymicrobial sepsis

BACKGROUND

No drug therapy has demonstrated improved clinical outcomes in the treatment of sepsis. A bolus of adenosine, lidocaine, and magnesium (ALM) has been shown to be cardioprotective and restore coagulopathy in different trauma states. We hypothesized that ALM therapy may improve hemodynamics, protect the lung, and prevent coagulopathy in the rat sepsis model.

METHODS

Nonheparinized, anesthetized Sprague-Dawley rats (350-450 g, n = 32) were randomly assigned to (1) shams (without sepsis), (2) saline controls, and (3) ALM treatment. Sepsis was induced by cecal ligation and puncture. A 0.3-mL bolus was administered intravenously, followed by a 4-hour intravenous infusion (1 mL/kg/h), and hemodynamics (mean arterial pressure [MAP], systolic arterial pressure, diastolic arterial pressure, and heart rate [HR]) and body temperature (BT) were monitored. Coagulation was assessed using prothrombin time and activated partial thromboplastin time (aPTT).

RESULTS

Shams displayed progressive falls in MAP, HR, and BT as well as a prolonged aPTT, which were related to surgery, not infection. At 4 hours, controls showed more pronounced falls in MAP (33%), HR (17%), and BT (3.3°C), and MAP continued to fall after the infusion was stopped. In contrast, ALM treatment resulted in a rapid fall in MAP from 111 mm Hg to 73 mm Hg at 30 minutes (p < 0.05 all groups) and was 59 mm Hg at 240 minutes (p < 0.05 shams), which immediately corrected after 4 hours (p < 0.05 controls). HR paralleled MAP changes in ALM rats, and BT was significantly higher than that of the controls but not that of shams. ALM rats had no arrhythmias compared with the controls or shams and had significantly lower lung wet-dry ratios. Prothrombin time in saline controls at 1 hour and 5 hours was prolonged but not in the shams or ALM rats. aPTT at 1 hour in the sham, control, and ALM groups was 158 ± 41 seconds, 161 ± 41 seconds, and 54 ± 23 seconds and at 5 hours was 104 ± 43 seconds, 205 ± 40 seconds, and 33 ± 3 seconds (p < 0.05), respectively.

CONCLUSION

An ALM bolus/infusion induces a stable, hypotensive hemodynamic state with no arrhythmias, significantly less pulmonary edema, and a higher BT and prevents coagulopathy compared with the controls.

Pulmonary function after hemorrhagic shock and resuscitation in a porcine model

BACKGROUND

Hemorrhagic shock may trigger an inflammatory response and acute lung injury. The combination adenosine, lidocaine (AL) plus Mg(2+) (ALM) has organ-protective and anti-inflammatory properties with potential benefits in resuscitation.The aims of this study were to investigate: (1) pulmonary function and inflammation after hemorrhagic shock; (2) the effects of ALM/AL on pulmonary function and inflammation.

METHODS

Pigs (38 kg) were randomized to: sham + saline (n = 5); sham + ALM/AL (n = 5); hemorrhage control (n = 11); and hemorrhage + ALM/AL (n = 9). Hemorrhage animals bled to a mean arterial pressure (MAP) of 35 mmHg for 90 min, received resuscitation with Ringer's acetate and 20 ml of 7.5% NaCl with ALM to a minimum MAP of 50 mmHg, after 30 min shed blood and 0.9% NaCl with AL were infused. Hemorrhage controls did not receive ALM/AL. Primary endpoints were pulmonary wet/dry ratio, PaO2 /FiO2 ratio (partial pressure of arterial oxygen to the fraction of inspired oxygen), cytokine and protein measurements in bronchoalveolar lavage fluid (BALF) and lung tissue, neutrophil invasion and blood flow in lung tissue.

RESULTS

In the hemorrhage groups, wet/dry ratio increased significantly compared with the sham groups. PaO2 /FiO2 ratio decreased during shock but normalized after resuscitation. BALF did not indicate significant pulmonary inflammation, oxidative stress or increased permeability. Intervention with ALM caused a temporary increase in pulmonary vascular resistance and reduced urea diffusion across the alveolar epithelia, but had no effect on wet/dry ratio.

CONCLUSION

Hemorrhagic shock and resuscitation did not cause acute lung injury or pulmonary inflammation. The question whether ALM/AL has the potential to attenuate acute lung injury is unanswered.

Small-volume 7.5% NaCl adenosine, lidocaine, and Mg2+ has multiple benefits during hypotensive and blood resuscitation in the pig following severe blood loss: rat to pig translation

OBJECTIVES

Currently, there is no effective small-volume fluid for traumatic hemorrhagic shock. Our objective was to translate small-volume 7.5% NaCl adenosine, lidocaine, and Mg hypotensive fluid resuscitation from the rat to the pig.

DESIGN

Pigs (35-40 kg) were anesthetized and bled to mean arterial pressure of 35-40 mm Hg for 90 minutes, followed by 60 minutes of hypotensive resuscitation and infusion of shed blood. Data were collected continuously.

SETTING

University hospital laboratory.

SUBJECTS

Female farm-bred pigs.

INTERVENTIONS

Pigs were randomly assigned to a single IV bolus of 4 mL/kg 7.5% NaCl + adenosine, lidocaine and Mg (n = 8) or 4 mL/kg 7.5% NaCl (n = 8) at hypotensive resuscitation and 0.9% NaCl ± adenosine and lidocaine at infusion of shed blood.

MEASUREMENTS AND MAIN RESULTS

At 60 minutes of hypotensive resuscitation, treatment with 7.5% NaCl + adenosine, lidocaine, and Mg generated significantly higher mean arterial pressure (48 mm Hg [95% CI, 44-52] vs 33 mm Hg [95% CI, 30-36], p < 0.0001), cardiac index (76 mL/min/kg [95% CI, 63-91] vs 47 mL/min/kg [95% CI, 39-57], p = 0.002), and oxygen delivery (7.6 mL O2/min/kg [95% CI, 6.4-9.0] vs 5.2 mL O2/min/kg [95% CI, 4.4-6.2], p = 0.003) when compared with controls. Pigs that received adenosine, lidocaine, and Mg/adenosine and lidocaine also had significantly lower blood lactate (7.1 mM [95% CI, 5.7-8.9] vs 11.3 mM [95% CI, 9.0-14.1], p = 0.004), core body temperature (39.3°C [95% CI, 39.0-39.5] vs 39.7°C [95% CI, 39.4-39.9]), and higher base excess (-5.9 mEq/L [95% CI, -8.0 to -3.8] vs -11.2 mEq/L [95% CI, -13.4 to -9.1]). One control died from cardiovascular collapse. Higher cardiac index in the adenosine, lidocaine, and Mg/adenosine and lidocaine group was due to a two-fold increase in stroke volume. Left ventricular systolic ejection times were significantly higher and inversely related to heart rate in the adenosine, lidocaine, and Mg/adenosine and lidocaine group. Thirty minutes after blood return, whole-body oxygen consumption decreased in pigs that received adenosine, lidocaine, and Mg/adenosine and lidocaine (5.7 mL O2/min/kg [95% CI, 4.7-6.8] to 4.9 mL O2/min/kg [95% CI, 4.2-5.8]), whereas it increased in controls (4.2 mL O2/min/kg [95% CI, 3.5-5.0] to 5.8 mL O2/min/kg [95% CI, 4.9-5.8], p = 0.02). After 180 minutes, pigs in the adenosine, lidocaine, and Mg/adenosine and lidocaine group had three-fold higher urinary output (2.1 mL//kg/hr [95% CI, 1.2-3.8] vs 0.7 mL//kg/hr [95% CI, 0.4-1.2], p = 0.001) and lower plasma creatinine levels.

CONCLUSION

Small-volume resuscitation with 7.5% NaCl + adenosine, lidocaine, and Mg/adenosine and lidocaine provided superior cardiovascular, acid-base, metabolic, and renal recoveries following severe hemorrhagic shock in the pig compared with 7.5% NaCl alone.

Adenosine, lidocaine, and Mg2+ (ALM™) increases survival and corrects coagulopathy after eight-minute asphyxial cardiac arrest in the rat

INTRODUCTION

No drug therapy has demonstrated improved survival following cardiac arrest (CA) of cardiac or noncardiac origin. In an effort to translate the cardiorescue properties of Adenocaine (adenosine and lidocaine) and magnesium sulfate (ALM) from cardiac surgery and hemorrhagic shock to resuscitation, we examined the effect of ALM on hemodynamic rescue and coagulopathy following asphyxial-induced CA in the rat.

METHODS

Nonheparinized animals (400-500 g, n = 39) were randomly assigned to 0.9% saline (n = 12) and 0.9% saline ALM (n = 10) groups. After baseline data were acquired, the animal was surface cooled (33°C-34°C) and the ventilator line clamped for 8 min inducing CA; 0.5 mL of solution was injected intravenously followed by 60-s chest compressions (300/min), and rats were rewarmed. Return of spontaneous circulation (ROSC), mean arterial pressure, heart rate, and rectal temperature were recorded for 2 h. Additional rats were randomized for rotation thromboelastometry measurements (n = 17).

RESULTS

Rats treated with ALM had a significant survival benefit (100% ALM vs. 67% controls achieved ROSC) and generated a higher mean arterial pressure than did controls after 75 min (81 vs. 72 mmHg at 120 min, P < 0.05). In all rats, rotation thromboelastometry lysis index decreased during CA, implying hyperfibrinolysis. Control ROSC survivors displayed hypocoagulopathy (prolonged EXTEM/INTEM clotting time, clot formation time, prothrombin time, activated partial thromboplastin time), decreased maximal clot firmness, lowered elasticity, and lowered clot amplitudes but no change in lysis index. These coagulation abnormalities were corrected by ALM at 120 min after ROSC.

CONCLUSIONS

Small bolus of 0.9% NaCl ALM improved survival and hemodynamics following nonhemorrhagic, asphyxial CA and corrected prolonged clot times and clot retraction compared with controls.

The Bellamy challenge: it's about time

In 1984, Col. Ronald Bellamy launched a worldwide challenge to develop a new resuscitation fluid to aid survival after catastrophic blood loss on the battlefield. In 1996, after careful compromise among need, cube weight and efficacy, the US military and later coalition forces adopted 6% hetastarch (HES) fluids for early resuscitation. In the intervening years, evidence has amassed indicating that the HES fluids may not be safe, and in June 2013 the US Food and Drug Administration issued a warning that HES solutions should not be used to treat patients with hypovolaemia or the critically ill. We review the unique challenges of early battlefield resuscitation, why the 'Bellamy challenge' remains open and discuss a number of forward-looking strategies that may help to solve the problem. The first two pillars of resuscitation that we believe have not been adequately addressed are rescuing and stabilising the heart (and brain) and the vascular system. The 'ideal' resuscitation fluid needs to nurture the heart and body slowly back to health, and not 'shock' it a second time with unnatural colloids or large volumes of unphysiological saline-based solutions.

Hemodynamic rescue and ECG stability during chest compressions using adenosine and lidocaine after 8-minute asphyxial hypoxia in the rat

INTRODUCTION

Sudden cardiac death generally arises from either ventricular fibrillation or asphyxial hypoxia. In an effort to translate the cardioprotective effects of adenosine and lidocaine (AL) from hemorrhagic shock to cardiopulmonary resuscitation, we examined the effect of AL on hemodynamics and electrocardiogram (ECG) stability in the rat model of asphyxial hypoxia.

METHODS

Male Sprague-Dawley rats were randomly assigned to 1 of 4 groups (n = 8): saline (SAL), adenosine (ADO), lidocaine (LIDO), and AL. Cardiac arrest (mean arterial pressure <10 mm Hg) was induced by clamping the ventilator line for 8 minutes. A 0.5-mL intravenous drug bolus was injected followed by chest compressions (300 min(-1)), which were repeated every 5 minutes for 1 hour.

RESULTS

Return of spontaneous circulation was achieved in 5 SAL (62.6%), 4 ADO (50%), 7 LIDO (87.5%), and 8 AL rats (100%) within 5 minutes but could not be sustained. During chest compressions, mean arterial pressure was consistently higher in the AL-treated rats compared with all groups (P < .05; 35-45 and 55 minutes) followed by the LIDO group and was lowest in the ADO and SAL groups (P < .05). Systolic pressure followed a similar pattern. In addition, diastolic pressure in the AL-treated rats was significantly higher from 25 to 60 minutes than LIDO and ADO alone or SAL, and heart rate was 30% to 40% lower. Improved ECG rhythm and R-R variability were apparent in AL-treated rats during early compressions and hands-off intervals.

CONCLUSIONS

We conclude that a small bolus of 0.9% NaCl AL improved hemodynamics with possible diastolic rescue and ECG stabilization during chest compressions compared with ADO, LIDO, or SAL controls.

Hyperkalemic cardioplegia for adult and pediatric surgery: end of an era?

Despite surgical proficiency and innovation driving low mortality rates in cardiac surgery, the disease severity, comorbidity rate, and operative procedural difficulty have increased. Today's cardiac surgery patient is older, has a "sicker" heart and often presents with multiple comorbidities; a scenario that was relatively rare 20 years ago. The global challenge has been to find new ways to make surgery safer for the patient and more predictable for the surgeon. A confounding factor that may influence clinical outcome is high K(+) cardioplegia. For over 40 years, potassium depolarization has been linked to transmembrane ionic imbalances, arrhythmias and conduction disturbances, vasoconstriction, coronary spasm, contractile stunning, and low output syndrome. Other than inducing rapid electrochemical arrest, high K(+) cardioplegia offers little or no inherent protection to adult or pediatric patients. This review provides a brief history of high K(+) cardioplegia, five areas of increasing concern with prolonged membrane K(+) depolarization, and the basic science and clinical data underpinning a new normokalemic, "polarizing" cardioplegia comprising adenosine and lidocaine (AL) with magnesium (Mg(2+)) (ALM™). We argue that improved cardioprotection, better outcomes, faster recoveries and lower healthcare costs are achievable and, despite the early predictions from the stent industry and cardiology, the "cath lab" may not be the place where the new wave of high-risk morbid patients are best served.

Adenocaine and Mg(2+) reduce fluid requirement to maintain hypotensive resuscitation and improve cardiac and renal function in a porcine model of severe hemorrhagic shock*

OBJECTIVES

Hypotensive resuscitation is gaining clinical acceptance in the treatment of hemorrhagic shock. Our aims were to investigate: 1) the effect of 7.5% NaCl with adenocaine (adenosine and lidocaine, AL) and AL with Mg (ALM) on fluid requirement to maintain a minimum mean arterial pressure of 50 mm Hg, and 2) the effect of a second bolus of 0.9% NaCl with AL during return of shed blood on cardiac and renal function in a porcine model of hemorrhagic shock.

DESIGN

Pigs were randomized to: Sham (n = 5), Sham + ALM/AL (n = 5), hemorrhage control (n = 11), or hemorrhage + ALM/AL (n = 9). Hemorrhage animals were bled to a mean arterial pressure of 35 mm Hg. After 90 mins, pigs were fluid resuscitated with Ringers acetate and 20 mL 7.5% NaCl with ALM to maintain a target mean arterial pressure of minimum 50 mm Hg. Shed blood and 0.9% NaCl with AL were infused 30 mins later. Hemorrhage control group was subjected to the same protocol but without ALM/AL. Hemodynamics, cardiodynamics (pressure-volume analysis), oxygen consumption, and kidney function were measured for 6 hrs.

SETTING

University hospital laboratory.

SUBJECTS

Female farm-bred pigs.

RESULTS

Fluid volume infused during hypotensive resuscitation was 40% less in the 7.5% NaCl-/ALM-treated pigs than controls (25 vs. 41 mL/kg, p < .05). ALM was associated with a significant increase in dp/dtmax, end-systolic blood pressure, and systemic vascular resistance. Return of shed blood and 0.9% NaCl/AL reduced whole body oxygen consumption by 27% (p < .05), and significantly improved the end-systolic pressure-volume relationship and preload recruitable stroke work compared to controls. Glomerular filtration rate in the ALM/AL group returned to 83% of baseline compared to 54% in controls (p = .01).

CONCLUSION

Resuscitation with 7.5% NaCl ALM increases cardiac function and reduces fluid requirements during hypotensive resuscitation, whereas a second AL infusion during blood resuscitation transiently reduces whole body oxygen consumption and improves cardiac and renal function.

Reversal of acute coagulopathy during hypotensive resuscitation using small-volume 7.5% NaCl adenocaine and Mg2+ in the rat model of severe hemorrhagic shock

OBJECTIVE

Acute traumatic coagulopathy occurs early in hemorrhagic trauma and is a major contributor to mortality and morbidity. Our aim was to examine the effect of small-volume 7.5% NaCl adenocaine (adenosine and lidocaine, adenocaine) and Mg on hypotensive resuscitation and coagulopathy in the rat model of severe hemorrhagic shock.

DESIGN

Prospective randomized laboratory investigation.

SUBJECTS

A total of 68 male Sprague Dawley Rats.

INTERVENTION

Post-hemorrhagic shock treatment for acute traumatic coagulopathy.

MEASUREMENTS AND METHODS

Nonheparinized male Sprague-Dawley rats (300-450 g, n=68) were randomly assigned to either: 1) untreated; 2) 7.5% NaCl; 3) 7.5% NaCl adenocaine; 4) 7.5% NaCl Mg²⁺; or 5) 7.5% NaCl adenocaine/Mg²⁺. Hemorrhagic shock was induced by phlebotomy to mean arterial pressure of 35-40 mm Hg for 20 mins (~40% blood loss), and animals were left in shock for 60 mins. Bolus (0.3 mL) was injected into the femoral vein and hemodynamics monitored. Blood was collected in Na citrate (3.2%) tubes, centrifuged, and the plasma snap frozen in liquid N2 and stored at -80°C. Coagulation was assessed using activated partial thromboplastin times and prothrombin times.

RESULTS

Small-volume 7.5% NaCl adenocaine and 7.5% NaCl adenocaine/Mg²⁺ were the only two groups that gradually increased mean arterial pressure 1.6-fold from 38-39 mm Hg to 52 and 64 mm Hg, respectively, at 60 mins (p<.05). Baseline plasma activated partial thromboplastin time was 17±0.5 secs and increased to 63±21 secs after bleeding time, and 217±32 secs after 60-min shock. At 60-min resuscitation, activated partial thromboplastin time values for untreated, 7.5% NaCl, 7.5% NaCl/Mg²⁺, and 7.5% NaCl adenocaine rats were 269±31 secs, 262±38 secs, 150±43 secs, and 244±38 secs, respectively. In contrast, activated partial thromboplastin time for 7.5% NaCl adenocaine/Mg²⁺ was 24±2 secs (p<.05). Baseline prothrombin time was 28±0.8 secs (n=8) and followed a similar pattern of correction.

CONCLUSIONS

Plasma activated partial thromboplastin time and prothrombin time increased over 10-fold during the bleed and shock periods prior to resuscitation, and a small-volume (~1 mL/kg) IV bolus of 7.5% NaCl AL/Mg²⁺ was the only treatment group that raised mean arterial pressure into the permissive range and returned activated partial thromboplastin time and prothrombin time clotting times to baseline at 60 mins.

Unexpected 100% survival following 60% blood loss using small-volume 7.5% NaCl with adenocaine and Mg(2+) in the rat model of extreme hemorrhagic shock

Hemorrhage is responsible for up to 40% of trauma mortality, and of these deaths, 33% to 56% occur during the prehospital period. In an effort to translate the cardioprotective effects of Adenocaine (adenosine, lidocaine) and Mg (ALM) from cardiac surgery to resuscitation science, we examined the early resuscitative effects of 7.5% NaCl with ALM in the rat model of 60% blood loss. Male Sprague-Dawley rats (250-350 g, n = 40) were anesthetized and randomly assigned to one of five groups: (a) untreated, (b) 7.5% NaCl, (c) 7.5% NaCl/6% dextran 70, (d) 7.5% NaCl/Mg, and (e) 7.5% NaCl/ALM. Blood withdrawal occurred over ∼50 min (MAP 30-35 mmHg), and rats were left in shock for 30 min. Total shock time was ∼80 min; 0.3-mL bolus was injected intravenously over 10 s, and hemodynamics monitored for 60 min (phase 1). Shed blood was reinfused and function monitored for a further 60 min (phase 2). Lead II electrocardiogram, arterial pressures, mean arterial pressure (MAP), pulse pressure (PP), heart rate (HR), and rate-pressure product were monitored. Mortality was as follows: untreated (100%), 7.5% NaCl (75%), 7.5% NaCl/6% dextran 70 (87.5%), 7.5% NaCl/Mg (62.5%), and 7.5% NaCl/ALM (0%). Deaths occurred at different times depending on treatment group and paralleled differences in the total number of ventricular arrhythmias with the highest number in untreated animals (49 ± 17) and lowest in 7.5% NaCl/ALM rats (2 ± 1.8) (P < 0.05). At the end of phase 1, MAP of 7.5% NaCl/ALM-treated animals increased from 29 to 40 mmHg (P < 0.05). At the end of phase 2, MAP, PP, HR, and rate-pressure product in the ALM group were 75%, 193%, 96%, and 83% of their preshock values. Small-volume (∼1 mL/kg) i.v. bolus of 7.5% NaCl/ALM led to 100% survival following 60% blood loss with higher MAP than any group, an 89% to 96% reduction in the total number of arrhythmias, and a stable HR.