Vasoplegic Shock Treated with Methylene Blue Complicated by Severe Serotonin Syndrome

The Use of Methylene Blue in Conjunction With Hydroxocobalamin and Multiple Pressors to Treat Severe Vasoplegia in a Patient Due to Calcium Channel Blocker Toxicity: A Case Report

Vasoplegia, the demonstration of persistently low systemic vascular resistance (SVR) and resistant hypotension in the presence of a normal cardiac index despite aggressive resuscitation attempts, is a serious clinical diagnosis that requires prompt treatment to prevent patient morbidity and mortality. Currently, treatment of vasoplegia involves treatment with vasopressors such as vasopressin, norepinephrine, and hydroxocobalamin. However, some evidence suggests that in addition to this treatment regimen, the addition of methylene blue may result in a reduction in overall norepinephrine equivalent vasopressor requirements, increased mean arterial pressure, and an improved clinical course. Here, we report the case of a 64-year-old male patient who presented to the ED after being found unresponsive and covered in emesis at home. The patient's presentation was complicated by worsening dyspnea, hypotension, and hemodynamic instability, requiring intubation and admission to the ICU for management of undifferentiated shock of unclear etiology and acute respiratory failure. Urine studies were consistent with a diagnosis of vasoplegia due to dihydropyridine calcium channel blocker toxicity, which was confirmed by pill counting of his home medications in the setting of recent paranoia and depression. The patient was treated aggressively with vasopressors, including vasopressin, phenylephrine, and epinephrine, as well as a combination of hydroxocobalamin and methylene blue. He was also started on a calcium and insulin drip. Upon initiation of non-catecholamine agents for vasoplegia, his clinical course quickly improved, and he was weaned from all vasopressors. He regained hemodynamic stability, was successfully extubated, evaluated by psychiatry, and discharged from the hospital in a stable condition on day 15 with the continuation of outpatient psychiatric services.

Anticholinergic Toxidrome as a Possible Explanation for Methylene Blue Toxicity

BACKGROUND Methylene blue has multiple uses in medicine. It is generally used to treat refractory vasoplegia and methemoglobin toxicity, and can be used as a dye to localize the parathyroid glands intra-operatively. In refractory vasoplegia, methylene blue inhibits endothelial nitric oxide and guanylate cyclase, causing vasoconstriction and potentially stabilizing blood pressure. Multiple complications have been associated with the use of methylene blue. These are related to either the sole effect of methylene blue or the combined effect of methylene blue and certain antidepressants, such as selective serotonin reuptake inhibitors (SSRIs). To the best of our knowledge, in the setting of post-cardiac surgery vasoplegia, there have been no reports of the neurological toxicity of methylene blue in the absence of SSRI use. In this case report, we describe the anticholinergic manifestations associated with the use of methylene blue in post-cardiac surgery vasoplegia. CASE REPORT A male patient in his mid-sixties with severe mitral regurgitation underwent elective mitral valve replacement. Postoperatively, he was hypotensive and required a high dose of vasopressors. Methylene blue was administered to treat refractory vasoplegia. The patient became anuric and febrile, with bilateral mydriasis. Internal cooling and continuous renal replacement therapy were initiated, and symptoms rapidly resolved. The patient was discharged after prolonged hospitalization with a permanent catheter for hemodialysis. CONCLUSIONS Anticholinergic toxidrome may explain the neurological adverse effects associated with high doses of methylene blue. Physicians should be cautious when using methylene blue in combination with other anticholinergic drugs and in conditions of renal failure. The development of methylene blue toxicity warrants the urgent discontinuation of the agent and early drug elimination.

Perioperative Considerations for Patients Exposed to Psychostimulants

Concerns regarding the perioperative management of acute psychostimulant intoxication have been recognized for decades, but novel and diverse substances in this class continue to be developed. Despite the similarities in mechanisms of action among psychostimulants, each subclass within this broad category has unique receptor specificity and different mechanisms that play a role in patient clinical presentation. These issues present challenges to anesthesia providers when caring for patients with either acute or chronic exposure to psychostimulants during the perioperative period. Challenges result from both physiological and psychological effects that influence the action of the primary anesthetic agent, adjuvant anesthetics, and analgesics used for perioperative management of pain. The epidemiology, pharmacology, and perioperative implications of psychostimulant use are presented for amphetamines and similar acting nonamphetamines, cocaine, and, finally, the mixed-action drugs known as entactogens that share stimulant and psychedelic properties. This information is then used as the foundation for safe and effective perioperative management of patients exposed to psychostimulants.

Methylene Blue Use in Pediatrics

Catecholamine-resistant shock, also known as vasoplegia, is a challenging entity with a significant risk of mortality. We seek to provide further data on the safety and effectiveness of methylene blue (MB) for vasoplegic shock in the pediatric population. We conducted a retrospective observational study of pediatric patients admitted to the pediatric intensive care unit or pediatric cardiac intensive care unit at Mount Sinai Kravis Children's Hospital from 2011 to 2021 who received MB for refractory shock. A list of patients was obtained by performing a pharmaceutical query from 2011 to 2021 for “MB.” Chart review was performed to determine indication for use and to collect demographic and clinical data. There were 33 MB administrations: 18 administrations (16 unique patients) for vasoplegic shock, 11 for surgical dye, and 4 for methemoglobinemia. The median age was 5 years (interquartile range [IQR]: 0.08, 13). Ten patients required MB following congenital cardiac repair (62.5%); one administration for myocarditis, septic shock, postcardiac arrest, high output chylothorax, scoliosis repair, and one multisystem inflammatory syndrome in children. No patients experienced hemolytic anemia or serotonin syndrome following administration. The median dose of MB was 1 mg/kg. Vasoactive-inotrope score (VIS) improved in 4 out of 18 administrations at 1 hour. Mean arterial pressure (MAP) improved in 10 out of 18 administrations at 1 hour. Systolic blood pressure (SBP) improved in 8 out of 18 administrations at 1 hour. VIS, MAP, and SBP improved in 8 out of 18 administrations at 6 hours. MB may be safely considered as rescue therapy in catecholamine-resistant shock in pediatrics.

Angiotensin axis antagonists increase the incidence of haemodynamic instability in dihydropyridine calcium channel blocker poisoning

CONTEXT

Amlodipine, a dihydropyridine calcium channel blocker (CCB), is the leading cause of cardiovascular drug-related overdose deaths in the USA. In contrast, angiotensin-II receptor blockers (ARBs) and angiotensin converting enzyme inhibitors (ACEIs) cause minimal toxicity in overdose. ACEIs/ARBs are often combined with dihydropyridines in hypertension treatment. Co-ingested ARBs/ACEIs may significantly contribute to the toxicity of dihydropyridine, but this has not been investigated.

OBJECTIVE

To investigate the clinical outcomes from dihydropyridine overdoses with ARBs/ACEIs versus dihydropyridine overdoses alone.

METHODS

This was a retrospective study of patients reported to the New South Wales Poisons Information Centre (NSW PIC) and 3 toxicology units (Jan 2016 to Jun 2019) in Australia. Patients >14 years who took an overdose of dihydropyridines (amlodipine, felodipine, lercanidipine, nifedipine) were included. Concurrent overdoses with non-dihydropyridine CCBs, alpha-blockers and beta-blockers were excluded. Patient demographics, drugs exposure details, serial vital signs, treatments and outcome were collected.

RESULTS

There were 100 patients. 68 took mixed overdoses of dihydropyridines with ARBs/ACEIs and 32 took single overdoses of dihydropyridines without ARBs/ACEIs. The mixed group had lower median nadir mean arterial pressures (62 vs 75 mmHg, p < 0.001), more frequently had hypotension (OR 4.5, 95%CI: 1.7-11.9) or bradycardia (OR 8.8, 95%CI: 1.1-70). Multivariable analysis indicated the mixed overdoses had an 11.5 mmHg (95%CI: 4.9-18.1) lower minimum systolic blood pressure (SBP) compared with the single group; other factors associated with a lower minimum SBP were higher doses [2.3 mmHg (95%CI: 1.1-3.5) lower per 10 defined daily doses] and younger age [2.2 mmHg (95%CI: 0.3-4.2) higher per decade]. A larger proportion of the mixed ingestion group received intravenous fluids (OR 5.7, 95%CI: 1.8-18.6) and antidotes and/or vasopressors (OR 2.9, 95%CI: 1.004-8.6).

CONCLUSION

Combined overdoses of dihydropyridines with ARBs/ACEIs caused more significant hypotension and required more haemodynamic support than overdoses of dihydropyridines alone.

Rescue of Nimodipine-Induced Refractory Vasoplegia With Hydroxocobalamin in Subarachnoid Hemorrhage: A Case Report

Background:

We report a case of refractory vasoplegia after nimodipine administration that was unresponsive to triple vasopressor therapy and was rescued by IV hydroxocobalamin.

Case Summary:

An 84-year-old male presented comatose from a subarachnoid hemorrhage and developed severe hypotension unresponsive to three vasopressors following a single dose of enteral nimodipine. Multisystem point-of-care ultrasonography ruled out alternate etiologies of shock, indicating that this was likely a vasoplegic state caused by nimodipine. We administered 5 grams of IV hydroxocobalamin over 15 minutes due to the possibility of impaired nitric oxide metabolism as the driver of vasoplegia. This led to immediate improvement in hemodynamics and rapid discontinuation of vasopressors. The patient experienced chromaturia but no other adverse effects due to hydroxocobalamin.

Conclusions:

Nimodipine administration is a standard practice for patients with aneurysmal subarachnoid hemorrhage to reduce unfavorable outcomes from cerebral vasospasm. Although mild hypotension is a common side effect of nimodipine, in rare cases, it may become profound, leading to refractory vasoplegia. There is no evidence-base for reversal agents for nimodipine-induced vasoplegia, and this case is the first to demonstrate successful use of hydroxocobalamin as a potential rescue therapy. We also propose an algorithm for treatment of vasoplegia with consideration of medications that act on nitric oxide–mediated vasodilation and their side-effect profiles.

Methylene Blue for Refractory Shock in Children: A Systematic Review and Survey Practice Analysis

OBJECTIVES

Shock refractory to fluid and catecholamine therapy has significant morbidity and mortality in children. The use of methylene blue to treat refractory shock in children is not well described. We aim to collect and summarize the literature and define physicians' practice patterns regarding the use of methylene blue to treat shock in children.

DESIGN

We conducted a systematic search of MEDLINE, Embase, PubMed, Web of Science, Cochrane for studies involving the use of methylene blue for catecholamine-refractory shock from database inception to 2019. Collected studies were analyzed qualitatively. To describe practice patterns of methylene blue use, we electronically distributed a survey to U.S.-based pediatric critical care physicians. We assessed physician knowledge and experience with methylene blue. Survey responses were quantitatively and qualitatively evaluated.

SETTING

Pediatric critical and cardiac care units.

PATIENTS OR SUBJECTS

Patients less than or equal to 25 years old with refractory shock treated with methylene blue.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

One-thousand two-hundred ninety-three abstracts met search criteria, 139 articles underwent full-text review, and 24 studies were included. Studies investigated refractory shock induced by a variety of etiologies and found that methylene blue was generally safe and increased mean arterial blood pressure. There is overall lack of studies, low number of study patients, and low quality of studies identified. Our survey had a 22.5% response rate, representing 125 institutions. Similar proportions of physicians reported using (40%) or never even considering (43%) methylene blue for shock. The most common reasons for not using methylene blue were unfamiliarity with this drug, its proper dosing, and lack of evidentiary support.

CONCLUSIONS

Methylene blue appears safe and may benefit children with refractory shock. There is a stark divide in familiarity and practice patterns regarding its use among physicians. Studies to formally assess safety and efficacy of methylene blue in treating pediatric shock are warranted.