Methylene blue: potential use of an antique molecule in vasoplegic syndrome during cardiac surgery

Adverse Clinical Effects Associated With Non-catecholamine Pharmacologic Agents for Treatment of Vasoplegic Syndrome in Adult Cardiac Surgery

Vasoplegic syndrome is a relatively common complication that can happen during and after major adult cardiac surgery. It is associated with a higher rate of complications, including postoperative renal failure, longer duration of mechanical ventilation, and intensive care unit stay, as well as increased mortality. The underlying pathophysiology of vasoplegic syndrome is that of profound vascular hyporesponsiveness, and involves a complex interplay among inflammatory cytokines, cellular surface receptors, and nitric oxide (NO) production. The pharmacotherapy approaches for the treatment of vasoplegia include medications that increase vascular smooth muscle contraction via increasing cytosolic calcium in myocytes, reduce the vascular effects of NO and inflammation, and increase the biosynthesis of and vascular response to norepinephrine. Clinical trials have demonstrated the clinical efficacy of non-catecholamine pharmacologic agents in the treatment of vasoplegic syndrome. With an increase in their use today, it is important for clinicians to understand the adverse clinical outcomes and patient risk profiles associated with these agents, which will allow better-tailored medical therapy.

Cardioprotection by methylene Blue Against Epinephrine-Induced Cardiac Arrhythmias and Myocardial Injury

Methylene blue is used in the treatment of vasoplegic syndrome after cardiac surgery, anaphylaxis, and septic shock refractory to epinephrine and fluid resuscitation. In this study, we investigated the potential protective effect of methylene blue on the development of cardiac arrhythmias after injection of epinephrine in rats. Methylene blue was given intraperitoneally at doses of 50 or 100 mg/kg. Cardiac arrhythmia was then induced with 10 μg/kg of epinephrine intravenously. In untreated, control rats, epinephrine caused bradycardia (96.48 ± 1.06 vs. 365.03 ± 0.68 beats/min), increased PR interval (0.54 ± 0.04 vs. 0.039 ± 0.004), RR interval (0.64 ± 0.003 vs. 0.16 ± 0.004 sec), shortened QTc interval (0.067 ± 0.05 vs. 0.1 ± 0.004 sec), increased QRS duration (0.048 ± 0.005 vs. 0.028 ± 0.002 sec), decreased R wave amplitude (0.3 ± 0.03 vs. 0.49 ± 0.04 mv), decreased the height of the ST segment (-0.0696 ± 0.004 vs. -0.0054 ± 0.003 mv), and caused ventricular extrasystoles (7.92 ± 0.56 vs. 0.5 ± 0.5). Methylene blue given at 50 or 100 mg/kg increased the heart rate, decreased RR interval, QRS duration and the drop in the ST height, increased duration of QTc interval and R wave amplitude and decreased the number of extrasystoles. The histological study showed that methylene blue protected against myocardial structural disorganization, cellular damage, necrosis, and haemorrhage between muscle fibres induced by epinephrine injection. We conclude that methylene blue dose-dependently prevented epinephrine-induced arrhythmias and cardiac muscle injury.

Vasoplegic syndrome in patients undergoing heart transplantation

Objectives

To summarize the risk factors, onset time, and treatment of vasoplegic syndrome in patients undergoing heart transplantation.

Methods

The PubMed, OVID, CNKI, VIP, and WANFANG databases were searched using the terms "vasoplegic syndrome," "vasoplegia," "vasodilatory shock," and "heart transplant*," to identify eligible studies. Data on patient characteristics, vasoplegic syndrome manifestation, perioperative management, and clinical outcomes were extracted and analyzed.

Results

Nine studies enrolling 12 patients (aged from 7 to 69 years) were included. Nine (75%) patients had nonischemic cardiomyopathy, and three (25%) patients had ischemic cardiomyopathy. The onset time of vasoplegic syndrome varied from intraoperatively to 2 weeks postoperatively. Nine (75%) patients developed various complications. All patients were insensitive to vasoactive agents.

Conclusions

Vasoplegic syndrome can occur at any time during the perioperative period of heart tranplantation, especially after the discontinuation of bypass. Methylene blue, angiotensin II, ascorbic acid, and hydroxocobalamin have been used to treat refractory vasoplegic syndrome.

Methylene blue versus vasopressin analog for refractory septic shock in the preterm neonate: A randomized controlled trial

BACKGROUND

Refractory septic shock in neonates is still associated with high mortality, necessitating an alternative therapy, despite all currently available treatments. This study aims to assess the vasopressor effect of methylene blue (MB) in comparison to terlipressin (TP) as adjuvant therapy for refractory septic shock in the preterm neonate.

METHODS

A double-blinded randomized controlled trial was conducted in the Neonatal Intensive Care Units at Ain Shams University, Egypt. Thirty preterm neonates with refractory septic shock were randomized to receive either MB or TP as an adjuvant to conventional therapy. Both MB and TP were administered as an intravenous loading dose followed by continuous intravenous infusion. The hemodynamic variables, functional echocardiographic variables, and oxidant stress marker were assessed over a 24 h period together with the side effects of MB.

RESULTS

MB causes significant improvement in mean arterial blood pressure with a significant decrease of the norepinephrine requirements (1.15±0.21μm/kg/min at baseline vs. 0.55±0.15μm/kg/min at 24 h). MB infusion causes an increase of the pulmonary pressure (44.73±8.53 mmHg at baseline vs. 47.27±7.91 mmHg after 24 h) without affecting the cardiac output. Serum malonaldehyde decreased from 5.45±1.30 nmol/mL at baseline to 4.40±0.90 nmol/mL at 24 h in the MB group.

CONCLUSION

Administration of MB to preterm infants with refractory septic shock showed rapid increases in systemic vascular resistance and arterial blood pressure with minimal side effects.

Efficacy of methylene blue in a murine model of amlodipine overdose

INTRODUCTION

Amlodipine overdoses have significant cardiac toxicity and are difficult to treat. Methylene blue has potential as a treatment for overdoses.

METHODS

A randomized controlled study of methylene blue as a treatment for amlodipine toxicity was conducted in C57Bl/6 mice. A baseline echocardiography was followed by gavage administration of amlodipine (90 mg/kg). Five minutes after gavage, animals received either vehicle solution (controls) or methylene blue (20 mg/kg) by intra-peritoneal injection. Animals were continuously monitored, and cardiac parameters were acquired every 15 min up to two hours.

RESULTS

Only 50% of control animals survived to the two-hour endpoint compared to 83% that received methylene blue. Amlodipine delivery induced significant reduction in left ventricular ejection fraction (EF), fractional shortening (FS), stroke volume (SV), and cardiac output (CO) in the vehicle treated animals relative to animals in the treatment group (p < 0.05 vehicle versus Methylene blue for EF, FS, SV, CO, and HR).

DISCUSSION

The amlodipine dose induced cardiotoxicity that were effects were more pronounced in the untreated group. 50% vehicle controls quickly progressed into heart failure (within 90 min of exposure) and did not survive the two h observation endpoint. Distinctly, only one animal from the Methylene blue treatment group did not survive (83% survival) the study. Additionally, the surviving animals from the Methylene blue group displayed significantly higher ejection fraction, fractional shortening, stroke volume, and cardiac output compared to vehicle group, indicating that methylene blue preserved cardiac function.

CONCLUSION

In this mouse model of amlodipine overdose, methylene blue decreased cardiac toxicity.

Use of Intravenous Hydroxocobalamin without Methylene Blue for Refractory Vasoplegic Syndrome After Cardiopulmonary Bypass

Case series

Patients: Male, 71-year-old • Male, 71-year-old

Final Diagnosis: Vasoplegic syndrome

Symptoms: Refractory hypotension

Medication: —

Clinical Procedure: Cardiopulmonary bypass

Specialty: Anesthesiology

Methylene blue for vasoplegic syndrome in cardiopulmonary bypass surgery: A systematic review and meta-analysis

BACKGROUND

To evaluate the benefit of methylene blue as an adjunct treatment by assessing hemodynamic, morbidity rate, intensive care unit length of stay, and mortality rate outcomes in adult patients with vasoplegic syndrome.

METHODS

A systematic search through electronic databases including Pubmed, Embase, Scopus, and Medline for studies assessing the use of methylene blue in patients with vasoplegic syndrome compared to control treatments. The Newcastle-Ottawa Scale tool was used for observational studies, and Jadad Scale was used for controlled trials to assess the risk of bias.

RESULTS

This systematic review included six studies for qualitative synthesis and five studies for quantitative synthesis. Pooled analysis revealed that mean arterial pressure, systemic vascular resistance, heart rate, and hospital stay were not statistically significant in methylene blue administration compared to control. However, administration of methylene blue in vasoplegic syndrome patients significantly reduces renal failure (OR = 0.25; 95% CI = 0.08-0.75), development of multiple organ failure (OR = 0.09; 95% CI = 0.02-0.51), and mortality rate (OR = 0.12; 95% CI = 0.03-0.46).

CONCLUSION

Adjunct administration of methylene blue for vasoplegic syndrome patients significantly reduces renal failure, multiple organ failure, and mortality.

Clinical utility of midodrine and methylene blue as catecholamine-sparing agents in intensive care unit patients with shock

Shock is common in the intensive care unit, affecting up to one third of patients. Treatment of shock is centered upon managing hypotension and ensuring adequate perfusion via administration of fluids and catecholamine vasopressors. Due to the risks associated with catecholamine vasopressors, interest has grown in using catecholamine-sparing agents such as midodrine and methylene blue. Midodrine is an orally administered alpha-1 adrenergic agonist while methylene blue is an intravenously administered blue dye used to restore vascular tone and increase blood pressure. Separate MEDLINE, Scopus, and Embase database searches were conducted to assess literature revolving around these agents. Examples of search terms included "midodrine", "methylene blue", "critically ill", "shock", and "catecholamine-sparing." Several studies have evaluated their use in patients with shock and found potential benefits in terms of causing significant elevations in blood pressure and hastening catecholamine vasopressor discontinuation with few adverse effects; however, robust evidence is lacking for these off-label indications. Because of the variety of dosing strategies used and the incongruences between patient populations, it is also challenging to define finite recommendations. This review aims to summarize current evidence for the use of midodrine and methylene blue as catecholamine-sparing agents in critically ill patients with resolving or refractory shock.

Vasoplegic syndrome following cardiothoracic surgery-review of pathophysiology and update of treatment options

Vasoplegic syndrome is a common occurrence following cardiothoracic surgery and is characterized as a high-output shock state with poor systemic vascular resistance. The pathophysiology is complex and includes dysregulation of vasodilatory and vasoconstrictive properties of smooth vascular muscle cells. Specific bypass machine and patient factors play key roles in occurrence. Research into treatment of this syndrome is limited and extrapolated primarily from that pertaining to septic shock, but is evolving with the expanded use of catecholamine-sparing agents. Recent reports demonstrate potential benefit in novel treatment options, but large clinical trials are needed to confirm.

Nano-engineered Adsorbent for the Removal of Dyes from Water: A Review

Background:

The huge quantity of wastewater, containing poisonous and hazardous dyes, is released by various industries which pollute water in direct and indirect ways. Most of the dyes are a dangerous class of water contaminants which have affected the environment drastically. Some dyes such as congo red, rhodamine B, methylene blue, methyl violet, and crystal violet are a serious threat to human beings.

Remediation Method:

Numerous methods are available for the removal of dyes from water. Adsorption, being a superior and eco-friendly technique, has advantage of eliminating organic dyes because of the availability of materials as adsorbents. The inexpensive nanomaterials are a more attractive choice for remediation of various dyes due to their unique properties and offer an adequate pathway to adsorb any organic dye from water to overcome its hazardous effects on human health.

Results:

In this review, we have discussed the latest literature related to various types of synthesis, characterization and uses as adsorbent for highly adsorptive removal capacity of nanoparticles for organic dyes.

Conclusion:

Adsorption technology provides an attractive pathway for further research and improvement in more efficient nanoparticles, with higher adsorption capacity, for numerous dyes to eliminate the dyes discharged from various industries and thus reduce the contamination of water. Therefore, nanocomposites may contribute to future prospective water treatment process.

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.

Care of the Postoperative Pulmonary Resection Patient

Patients undergoing pulmonary resection all exhibit, to some degree, a level of pulmonary dysfunction. This is due to the physiologic stress of the procedure performed, the patient’s comorbidities, and preexisting cardiopulmonary reserve. Although prognostic factors for intensive care requirement exist, to date, there is no consensus for postoperative admission. Institutional practices vary across the country, with patients often admitted to intensive care for surveillance. Guidelines published from the American Thoracic Society in 1999 emphasize that admission to the ICU be reserved for those patients requiring care and monitoring for severe physiologic instability. Admissions following pulmonary resection are typically due to respiratory complications and are an independent predictor of mortality. The following chapter will review the indications for admission to the ICU and common issues encountered following pulmonary resection and conclude with a discussion of the management of patients undergoing pulmonary transplantation.

Improved survival after heart transplant for failed Fontan patients with preserved ventricular function

BACKGROUND

Patients with a failing Fontan continue to have decreased survival after heart transplant (HT), particularly those with preserved ventricular function (PVF) compared with impaired ventricular function (IVF). In this study we evaluated the effect of institutional changes on post-HT outcomes.

METHODS

Data were retrospectively collected for all Fontan patients who underwent HT. Mode of failure was defined by the last echocardiogram before HT, with mild or no dysfunction considered PVF and moderate or severe considered IVF. Outcomes were compared between early era (EE, 1995 to 2008) and current era (CE, 2009 to 2014). Management changes in the CE included volume load reduction with aortopulmonary collateral (APC) embolization, advanced cardiothoracic imaging, higher goal donor/recipient weight ratio and aggressive monitoring for post-HT vasoplegia.

RESULTS

A total of 47 patients were included: 27 in the EE (13 PVF, 14 IVF) and 20 in the CE (12 PVF, 8 IVF). Groups were similar pre-HT, except for more PLE in PVF patients. More patients underwent APC embolization in the CE (80% vs 28%, p < 0.01). There was no difference in donor/recipient weight ratio between eras. There was a trend toward higher primary graft failure for PVF in the EE (77% vs 36%, p = 0.05) but not the CE (42% vs 75%, p = 0.20). Overall, 1-year survival improved in the CE (90%) from the EE (63%) (p = 0.05), mainly due to increased survival for PVF (82 vs 38%, p = 0.04).

CONCLUSIONS

Post-HT survival for failing Fontan patients has improved, particularly for PVF. In the CE, our Fontan patients had a 1-year post-HT survival similar to other indications.

Nitric oxide inhibition strategies

Nitric oxide is involved in many physiologic processes. There are efforts, described elsewhere in this volume, to deliver nitric oxide to tissues as a therapy. Nitric oxide also contributes to pathophysiologic processes. Inhibiting nitric oxide or its production can thus also be of therapeutic benefit. This article addresses such inhibitory strategies.

Serotonin syndrome following methylene blue administration during cardiothoracic surgery

INTRODUCTION

Despite its favorable safety profile, there have been reports of methylene blue-induced encephalopathy and serotonin syndrome in patients undergoing parathyroidectomy. We report a case of serotonin syndrome following methylene blue administration in a cardiothoracic surgery patient.

CASE REPORT

A 59-year-old woman taking preoperative venlafaxine and trazodone was given a single dose of 2 mg/kg methylene blue (167 mg) during a planned coronary artery bypass and mitral valve repair. Postoperatively, she was febrile to 38.7°C and developed full-body tremors, rhythmic twitching of the perioral muscles, slow conjugate roving eye movements, and spontaneous movements of the upper extremities. Electroencephalography revealed generalized diffuse slowing consistent with toxic encephalopathy, and a computed tomography scan showed no acute process. The patient's symptoms were most consistent with a methylene blue-induced serotonin syndrome. Her motor symptoms resolved within 48 hours and she was eventually discharged home.

DISCUSSION

Only 2 cases of methylene blue-induced serotonin syndrome during cardiothoracic surgery have been described in the literature, with this report representing the third case. Methylene blue and its metabolite, azure B, are potent, reversible inhibitors of monoamine oxidase A which is responsible for serotonin metabolism. Concomitant administration of methylene blue with serotonin-modulating agents may precipitate serotonin syndrome.

Methylene blue modulates adhesion molecule expression on microvascular endothelial cells

OBJECTIVE AND DESIGN

As methylene blue (MB) has been recently proposed to preserve blood pressure in case of vasoplegic syndrome and shock, an entity directly related to systemic inflammation, we aimed to elucidate the effect of MB on the expression of adhesion-molecules in endothelial-cells.

MATERIALS AND TREATMENT

Human microvascular endothelial-cells (HuMEC-1) were treated with 10, 30 or 60 µM MB for 30 min and 2 h each. Additionally, the treated HuMEC-1 were co-cultured with either human peripheral blood mononuclear cells (PBMCs) or Jurkat cells (human T-lymphocytes) for 2 h.

METHODS

HuMEC-1 were analyzed after MB treatment and after co-culture experiments for expression of different adhesion-molecules (ICAM-1, VCAM-1, L-selectin, E-selectin) via FACS measurement and western blot analysis. The supernatants of the experiments were analyzed with regard to the soluble forms of the adhesion molecules.

RESULTS

We found that MB is able to modulate the expression of adhesion-molecules on EC. Administration of MB increases the expression of E-selectin and VCAM-1 depending on the dosage and time of exposure. ICAM-1 measurements provide evidence that different circulating blood cells can differently alter the adhesion-molecule expression on EC after MB exposure.

CONCLUSION

Our results provide evidence regarding the immunomodulatory effect of MB upon endothelial-cells after inflammation.

Moderate and deep hypothermia produces hyporesposiveness to phenylephrine in isolated rat aorta

BACKGROUND

Moderate and severe hypothermia with cardiopulmonary bypass during aortic surgery can cause some complications such as endothelial cell dysfunction or coagulation disorders. This study found out the difference of vascular reactivity by phenylephrine in moderate and severe hypothermia.

METHODS

Preserved aortic endothelium by excised rat thoracic aorta was sectioned, and then down the temperature rapidly to 25℃ by 15 minutes at 38℃ and then the vascular tension was measured. The vascular tension was also measured in rewarming at 25℃ for temperatures up to 38℃. To investigate the mechanism of the changes in vascular tension on hypothermia, NG-nitro-L-arginine methyl esther (L-NAME) and indomethacin administered 30 minutes before the phenylephrine administration. And to find out the hypothermic effect can persist after rewarming, endothelium intact vessel and endothelium denuded vessel exposed to hypothermia. The bradykinin dose-response curve was obtained for ascertainment whether endothelium-dependent hyperpolarization factor involves decreasing the phenylnephrine vascular reactivity on hypothermia.

RESULTS

Fifteen minutes of the moderate hypothermia blocked the maximum contractile response of phenylephrine about 95%. The vasorelaxation induced by hypothermia was significantly reduced with L-NAME and indomethacin administration together. There was a significant decreasing in phenylephrine susceptibility and maximum contractility after 2 hours rewarming from moderate and severe hypothermia in the endothelium intact vessel compared with contrast group.

CONCLUSION

The vasoplegic syndrome after cardiac surgery might be caused by hypothermia when considering the vascular reactivity to phenylephrine was decreased in the endothelium-dependent mechanism.

Methylene blue modulates transendothelial migration of peripheral blood cells

Vasoplegia is a severe complication after cardiac surgery. Within the last years the administration of nitric oxide synthase inhibitor methylene blue (MB) became a new therapeutic strategy. Our aim was to investigate the role of MB on transendothelial migration of circulating blood cells, the potential role of cyclic cGMP, eNOS and iNOS in this process, and the influence of MB on endothelial cell apoptosis. Human vascular endothelial cells (HuMEC-1) were treated for 30 minutes or 2 hours with different concentrations of MB. Inflammation was mimicked by LPS stimulation prior and after MB. Transmigration of PBMCs and T-Lymphocytes through the treated endothelial cells was investigated. The influence of MB upon the different subsets of PBMCs (Granulocytes, T- and B-Lymphocytes, and Monocytes) was assessed after transmigration by means of flow-cytometry. The effect of MB on cell apoptosis was evaluated using Annexin-V and Propidium Iodide stainings. Analyses of the expression of cyclic cGMP, eNOS and iNOS were performed by means of RT-PCR and Western Blot. Results were analyzed using unpaired Students T-test. Analysis of endothelial cell apoptosis by MB indicated a dose-dependent increase of apoptotic cells. We observed time- and dose-dependent effects of MB on transendothelial migration of PBMCs. The prophylactic administration of MB led to an increase of transendothelial migration of PBMCs but not Jurkat cells. Furthermore, HuMEC-1 secretion of cGMP correlated with iNOS expression after MB administration but not with eNOS expression. Expression of these molecules was reduced after MB administration at protein level. This study clearly reveals that endothelial response to MB is dose- and especially time-dependent. MB shows different effects on circulating blood cell-subtypes, and modifies the release patterns of eNOS, iNOS, and cGMP. The transendothelial migration is modulated after treatment with MB. Furthermore, MB provokes apoptosis of endothelial cells in a dose/time-dependent manner.