The guanylyl cyclase inhibition by MB as vasoplegic circulatory shock therapeutical target

Effect of methylene blue on hemodynamic and metabolic response in septic shock patients

INTRODUCTION

Septic shock is a lethal disease responsible for a large proportion of deaths in the Intensive Care Unit (ICU), even with therapy centered on fluid resuscitation, use of vasopressors and empirical antibiotic therapy applied within the first hour of diagnosis. Considering the multifactorial pathophysiology of septic shock and the mechanism of action of vasopressors, some patients may not respond adequately, which can lead to the maintenance of vasodilatation, hypotension and increased morbidity, and mortality. This protocol aims to verify whether the use of methylene blue in septic patients with an early diagnosis can contribute to an earlier resolution of a shock compared to standard treatment.

METHODS AND ANALYSIS

This is a study protocol for a single-center randomized clinical trial design in an ICU of a tertiary university hospital. In this study, we intend to include 64 patients aged between 18 and 80 years with a diagnosis of septic shock, of any etiology, with up to 72 hours of evolution after volume restoration, using norepinephrine at a dose ≥0.2 μg/kg/min and vasopressin at a dose of 0.04 IU/min. After the initial approach, we will randomize patients into two groups, standard care, and standard care plus methylene blue. The sample size was calculated in order to show 30% differences in septic shock resolution between groups. The Research Ethics Committee approved the study, and all patients included will sign an informed consent form (Clinical registration: RBR-96584w4).

Surgical adrenalectomy during rescue Extracorporeal Life Support for pheochromocytoma induced cardiogenic shock: a case report

Introduction : Pheochromocytoma, a rare catecholamine-producing tumor, has been described to provoke stress-induced Takotsubo-like cardiomyopathy and even severe refractory cardiogenic shock. In this case report, venoarterial extracorporeal membrane oxygenation (VA-ECMO) was used for hemodynamic stabilization and was continued during the resection of a large neuroendocrine tumor. Description : A 69-year old male, recently diagnosed with a pheochromocytoma, was referred to our center because of severe cardiogenic shock after induction of anesthesia for resection of the mass. Despite adequate alpha-and beta-adrenergic blockade for one month, he developed malignant hypertension with subsequently hemodynamic collapse. After successful cardiopulmonary resusci-tation he developed pulmonary oedema with severe hypoxemia and persistent hemodynamic lability. On arrival in our hospital, echocardiography revealed significant left ventricular impairment. Decision was made to commence him on VA-ECMO for a refractory cardiogenic shock with severe pulmonary oedema. Because of persistent blood pressure swings despite VA-ECMO and beta-adrenergic blockade, we decided to remove the tumor on mechanical circulatory support by an open surgical approach the next day. After clamping of the adrenal circulation, the patient experienced profound hypotension requiring high doses of epinephrine and a methylene blue infusion. Surgical resection was successful but complicated by a postoperative bleeding for which the patient underwent an emergent endovascular embolization of an adrenal artery. Over the next days, there was progressive cardiac recovery and the patient was weaned off VA-ECMO on the fourth postoperative day. The patient was discharged from the intensive care 27 days after admission and left the hospital on day 30. Discussion: VA-ECMO seems to be a feasible last resort therapy in refractory cardiogenic shock induced by pheochromocytoma crisis as suggested by a high survival rate in literature. Despite its support benefit during this type of shock, surgical removal of the tumor is rarely done with mechanical circulatory support and heparinization.

When the pressure drops: A case of vasoplegia during a structural heart intervention

A 67-year-old male underwent general anesthesia for left atrial appendage occlusion. During the procedure, the patient developed catecholamine refractory hypotension requiring the administration of several vasopressin boluses to maintain adequate perfusion pressure. At the conclusion of the procedure, mild venous bleeding necessitated the administration of protamine. This led to a further decrease in the patient's blood pressure. Tamponade and continued volume loss were quickly ruled out leading to a diagnosis of vasoplegia syndrome (VS). The patient was appropriately treated with a vasopressin infusion with normalization of blood pressure and no significant morbidity or adverse outcome. With the use of general anesthesia during structural heart interventions on the rapid rise, we discuss the two common causes for vasoplegia along with evidence-based treatments and possible prevention strategies.

Effects of methylene blue in acute lung injury induced by oleic acid in rats

BACKGROUND

In acute lung injury (ALI), rupture of the alveolar-capillary barrier determines the protein-rich fluid influx into alveolar spaces. Previous studies have reported that methylene blue (MB) attenuates such injuries. This investigation was carried out to study the MB effects in pulmonary capillary permeability.

METHODS

Wistar rats were divided into five groups: (I) Sham: saline bolus; (II) MB, MB infusion for 2 h; (III) oleic acid (OA), OA bolus; (IV) MB/OA, MB infusion for 2 h, and at 5 min after from the beginning, concurrently with an OA bolus; and (V) OA/MB, OA bolus, and after 2 h, MB infusion for 2 h. After 4 h, blood, bronchoalveolar lavage (BAL), and lung tissue were collected from all groups for analysis of plasma and tissue nitric oxide, calculation of the wet weight to dry weight ratio (WW/DW), and histological examination of lung tissue. Statistical analysis was performed using nonparametric test.

RESULTS

Although favourable trends have been observed for permeability improvement parameters (WW/WD and protein), the results were not statistically significant. However, histological analysis of lung tissue showed reduced lesion areas in both pre- and post-treatment groups.

CONCLUSIONS

The data collected using this experimental model was favourable only through macroscopic and histological analysis. These observations are valid for both MB infusions before or after induction of ALI.

A review of methylene blue treatment for cardiovascular collapse

BACKGROUND

Historically, methylene blue (MB) has been used for multiple purposes, including as an antidote for toxin-induced and hereditary methemoglobinemia, ifosfamide-induced encephalopathy, and ackee fruit and cyanide poisoning; as an aniline dye derivative, antimalarial agent, and antidepressant.

DISCUSSION

Most recently, the use of MB has been advocated as a potential adjunct in the treatment of shock states. Our article reviews the role of MB in septic shock, anaphylactic shock, and toxin-induced shock. MB is proposed to increase blood pressure in these shock states by interfering with guanylate cyclase activity, and preventing cyclic guanosine monophosphate production and vasodilatation.

SUMMARY

MB may be an adjunct in the treatment of septic shock, anaphylactic shock, and toxin-induced shock.

Anaphylaxis with Latrodectus antivenin resulting in cardiac arrest

Latrodectus mactans antivenin is a safe and effective therapy for severe black widow spider envenomations when given to most patients. We report a case of a 37-year-old male with a history of asthma that was given L. mactans antivenin for symptoms related to a black widow envenomation and developed a severe anaphylactic reaction resulting in cardiac arrest. When traditional therapies failed, the patient was given methylene blue for anaphylactic shock resulting in a 30-h period of hemodynamic stability. Despite initial resuscitation, the patient ultimately died 40 h after presentation. Under the right circumstances, L. mactans antivenin remains a safe and effective therapy for severe black widow envenomations. However, anaphylaxis is a risk for those receiving this therapy, even when the antivenin is diluted and given as an infusion. We report the first death related to diluted L. mactans antivenin given as an infusion.

Main Properties of the THERAFLEX MB-Plasma System for Pathogen Reduction

Methylene blue (MB) treated plasma has been in clinical use for 18 years. The current THERAFLEX MB-Plasma has a number of improved features compared with the original Springe methodology. This overview embodies: the biochemical characteristics of MB, the mechanism of the technology, toxicology, pathogen reduction capacity, current position in clinical setting and status within Europe. The THERAFLEX MB (TMB) procedure is a robust, well standardised system lending itself to transfusion setting and meets the current guidelines. The pathogen kill power of the TMB system, like the other available technologies, is not limitless, probably in order of 6 log for most enveloped viruses and considerably less for non-enveloped ones. It does not induce either new antigen or grossly reducing the function and life span of active principle in fresh frozen plasma (FFP). The removal of the residual MB at the end of the process has the beneficial effect of reducing potential toxic impacts. Clinical haemovigilance data, so far, indicate that cell-free MB plasma is effective in all therapeutic setting requiring FFP, besides inconsistent thrombotic thrombocytopenia purpura data, without serious side-effects or toxicity. The current system is in continuous improvement e.g. regarding virus reduction range, illumination device, software used, and process integration in the blood bank setting.

Use of methylene blue in pheochromocytoma resection: case report

We report the use of intravenous Methylene blue to treat the hypotension occurring following adrenal vein ligation in a case of pheochromocytoma resection in a child. The potential benefits and problems, including correct dosage, are discussed.

Neuro- and cardioprotective effects of blockade of nitric oxide action by administration of methylene blue

Methylene blue (MB), generic name methylthioninium (C(16)H(18)ClN(3) S . 3H(2)O), is a blue dye synthesized in 1876 by Heinrich Caro for use as a textile dye and used in the laboratory and clinically since the 1890s, with well-known toxicity and pharmacokinetics. It has experimentally proven neuroprotective and cardioprotective effects in a porcine model of global ischemia-reperfusion in experimental cardiac arrest. This effect has been attributed to MB's blocking effect on nitric oxide synthase and guanylyl cyclase, the latter blocking the synthesis of the second messenger of nitric oxide. The physiological effects during reperfusion include stabilization of the systemic circulation without significantly increased total peripheral resistance, moderately increased cerebral cortical blood flow, a decrease of lipid peroxidation and inflammation, and less anoxic tissue injury in the brain and the heart. The last two effects are recorded as less increase in plasma concentrations of astroglial protein S-100beta, as well as troponin I and creatine kinase isoenzyme MB, respectively.

Role of nitric oxide production in anaphylaxis and its relevance for the treatment of anaphylactic hypotension with methylene blue

OBJECTIVE

To review the role of nitric oxide production in anaphylaxis.

DATA SOURCES

We performed MEDLINE searches of the literature. In addition, some references known to the authors but not listed in MEDLINE, such as abstracts and a CD-ROM, were included. Finally, additional clinical details of the cases were provided by one of the authors.

STUDY SELECTION

Primary reports were preferentially selected for inclusion. However, some secondary publications are also cited.

RESULTS

Histamine along with other mediators, such as leukotrienes, tumor necrosis factor, and platelet-activating factor, induce the production of nitric oxide. Nitric oxide can inhibit the release and effects of catecholamines. Sympathetic amines may inhibit production of nitric oxide. Studies in animals have demonstrated the generation of nitric oxide during anaphylaxis. Inhibition of nitric oxide synthase improves survival in an animal model of anaphylaxis. Nitric oxide causes vasodilation indirectly by increasing the activation of guanylyl cyclase, which then causes smooth muscle relaxation by increasing the concentration of smooth muscle cyclic guanosine monophosphate. Methylene blue is an inhibitor of guanylyl cyclase, which increases systemic vascular resistance and reverses shock in animal studies. The previously reported successful treatment with methylene blue of 11 patients with anaphylactic hypotension is reviewed.

CONCLUSION

Nitric oxide plays a significant role in the pathophysiology of anaphylaxis. Treatment with methylene blue should be considered in patients with anaphylactic hypotension that has not responded to other interventions.

Is the cyclic GMP system underestimated by intensive care and emergency teams?

At present, the clinical management inflammatory vasoplegia associated to sepsis or anaphylaxis is symptomatic. Volume is expanded by means of administration of fluids, and low blood pressure is managed by means of administration of positive inotropes and vasoconstrictors. This therapeutic approach is mainly associated to the cyclic AMP (cAMP) and, many times the circulatory shock is refractory to high amines concentrations. However, beside of cAMP-dependent vasoreactivity mechanisms there are other two known vasoplegia involved mechanisms: cyclic GMP (cGMP) and hyperpolarization that is less clinically considered. Also, it is possible to speculate about 'probable vasopressin deficiency'. Methylene blue (MB) is the most useful and clinically safe cGMP blocker. We propose a decision tree for diagnosis and institution of this therapeutical approach many times underestimate by intensive care and emergency teams.