Early adjunctive methylene blue in patients with septic shock: a randomized controlled trial

Nitric oxide biomarkers and circulatory failure in critical illness: A cohort study

PURPOSE

Arterial hypotension is frequently observed in critically ill patients. Nitric oxide (NO) is pivotal in vasodilation. We investigated the associations between NO-biomarkers (asymmetrical dimethylarginine (ADMA), symmetric dimethylarginine (SDMA), arginine, and homoarginine) and treatment with norepinephrine and plasma lactate on ICU days 1-3.

MATERIALS AND METHODS

A prospective cohort study of 527 adult ICU patients with NO-biomarkers at admission. Associations with norepinephrine treatment were analyzed in logistic regressions on the first three days of ICU admission. Associations with the highest daily plasma lactate were analyzed with linear mixed models.

RESULTS

Increasing ADMA and arginine were associated with decreased norepinephrine treatment (ICU day 1: OR 0.36 pr 1 μmol/L ADMA, 95 % CI 0.17-0.78; p = 0.009, and OR 0.85 pr 10 μmol/L arginine; 95 % CI 0.79-0.92; p < 0.001). An increase in homoarginine of 1 μmol/L was associated with an increase in plasma lactate of 6 % (95 % CI -2 % to 15 %) from ICU days 1-2 and 4 % (95 % CI -4 % to 13 %) from ICU days 2-3. SDMA was not associated with either outcome.

CONCLUSIONS

Increased ADMA and arginine at admission are associated with decreased norepinephrine treatment on the first three days of ICU admission. Increased homoarginine concentrations are associated with increasing plasma lactate.

From Theory to Therapy: Methylene Blue's Emerging Role in the Management of Septic Shock

Purpose: Methylene blue was FDA-approved for the treatment of acquired methemoglobinemia. However, it has also shown benefits in other disease states such as β-blocker and calcium channel blocker overdoses, vasoplegia, and ifosfamide-induced encephalopathy. More recently, methylene blue has emerged as a potential catecholamine sparing agent for the treatment of septic shock through inhibition of the nitric oxide pathway, which is responsible for vasodilation. Studies suggest that methylene blue decreases vasopressor requirements for critically ill patients with minimal safety risks. This clinical review aims to review the pharmacology, efficacy, and safety surrounding methylene blue use in patients with septic shock. Summary: Six studies conducted between 2000 and 2024 were identified. In randomized studies, methylene blue appears to be safe and effective in improving hemodynamics in patients with septic shock. This review discusses pharmacology, pharmacotherapy, and primary literature surrounding methylene blue in septic shock. Conclusion: Based on review of the available literature, authors conclude that methylene blue is an appropriate catecholamine-sparing treatment option for patients with septic shock. However, drug-drug interactions should be carefully reviewed before administration due to the risk of serotonin syndrome when combined with other serotonergic agents.

ADJUNCTIVE VASOPRESSORS AND SHORT-TERM MORTALITY IN ADULTS WITH SEPTIC SHOCK: A SYSTEMATIC REVIEW AND META-ANALYSIS

ABSTRACT

Background: Adjunctive vasopressors are added to norepinephrine in one-third of adults with septic shock in the United States. However, effectiveness of this approach is unclear, and treatment recommendations are based on indirect evidence. We sought to synthesize the direct evidence for adjunctive vasopressor administration in adults with septic shock. Methods: We searched MEDLINE, Embase, and Cochrane Central Register of Controlled Trials from inception to June 7, 2023. We included randomized clinical trials of adults with septic shock comparing adjunctive treatment with a vasopressin analogue, angiotensin II, methylene blue, hydroxocobalamin, or catecholamine analog to standard care vasopressors. The primary outcome was short-term mortality (at or before 28-30 days or intensive care discharge). Secondary outcomes included kidney replacement therapy, digital/peripheral ischemia, and venous thromboembolism. Random-effects meta-analyses were conducted to derive risk ratios (RRs) and 95% CIs. The certainty of the evidence was assessed using Grading of Recommendations Assessment, Development, and Evaluation. Results: Of 6,763 records, 17 trials (3,813 participants) were included. Compared with standard care, adjunctive vasopressor administration may reduce short-term mortality risk (RR, 0.92 [95% CI, 0.85-1.00], low certainty, 17 trials [3618 participants]) and likely reduces kidney replacement therapy receipt (RR, 0.92 [95% CI, 0.84-1.01], moderate certainty, eight trials [2,408 participants]). Adjunctive vasopressor treatment may increase risk of digital/peripheral ischemia (RR, 2.44 [95% CI, 1.17-5.10], low certainty, nine trials [2,981 participants]) and venous thromboembolism (RR, 16.48 [95% CI, 0.96-283.17], low certainty, one trial [321 participants]). There was some evidence that the pooled estimate for short-term mortality was different (interaction P = 0.13) for trials adjudicated as low risk of bias (RR, 0.95 [95% CI, 0.87-1.05]) compared with trials adjudicated as some concerns or high risk of bias (RR, 0.82 [95% CI, 0.69-0.97]). The findings were robust to multiple sensitivity and subgroup analyses. Conclusions: In adults with septic shock, adjunctive vasopressors may lower short-term death risk and likely lower kidney replacement therapy risk, but may increase risk of adverse effects. In the United States, adjunctive vasopressor use prevalence in septic shock is disconnected from the low evidence certainty for a favorable mortality-to-risk profile.

Predicting responsiveness to fixed-dose methylene blue in adult patients with septic shock using interpretable machine learning: a retrospective study

This study aimed to develop an interpretable machine learning model to predict methylene blue (MB) responsiveness in adult patients with refractory septic shock and to identify key factors influencing MB responsiveness using the SHapley Additive exPlanations (SHAP) approach. We retrospectively analyzed data from 416 adult patients with refractory septic shock who received MB treatment at Xiangya Hospital of Central South University between June 2018 and October 2022. MB responders were defined as patients who, within 6 hours after MB administration, exhibited either a reduction in average norepinephrine equivalence (NEE) of ≥ 10% or an increase in mean arterial pressure of ≥ 10 mmHg without an associated increase in NEE. The incidence of MB responders was 38.2%(n=159). Statistical and machine learning methods were used for feature selection, resulting in two datasets (ST and ML). Each dataset was randomly divided into a training set (75%) for model development and a testing set (25%) for internal validation. Prediction models were developed using logistic regression, support vector machine (SVM), random forest, light gradient boosting machine (LightGBM), and explainable boosting machine (EBM). The models were evaluated regarding discrimination, calibration, and clinical benefit. The SVM model trained on the ML dataset demonstrated the best predictive performance, with an area under the curve (AUC) of 0.74 (95% CI 0.62-0.84), 76% accuracy, 36% sensitivity, and 94% specificity. Although the model's sensitivity was low, its high specificity and the safety profile of MB underscore its clinical relevance. The model showed superior net benefit within a 24-85% threshold probability, as determined by decision curve analysis. The SHAP analysis identified the average NEE dose within 6 hours before MB initiation as the most important factor influencing MB responsiveness (P<0.01), with higher doses positively correlating with a greater likelihood of response. Lactate levels were identified as the second most important factor. The optimal model was externally validated in an independent cohort from the same institution, achieving an AUC of 0.75 and an accuracy of 74%.

[Severe malnutrition during pregnancy complicated with acute pyelonephritis causing sepsis, refractory septic shock and multiple organ failure: A case report]

This study reports the diagnosis and treatment of a 26-year-old pregnant woman with severe malnutrition combined with acute pyelonephritis causing sepsis, refractory septic shock and multiple organ failure. A female patient, 26 years old, was admitted to hospital mainly due to "menelipsis for more than 19 weeks, nausea and vomiting for 20 days, fever with fatigue for 3 days". At the end of 19 weeks of intrauterine pregnancy, the patient presented with fever accompanied by urinary tract irritation. Laboratory tests showed elevated inflammatory indicators, and ultrasonography showed bilateral pelvicalyceal dilation. She was diagnosed with acute pyelonephritis, sepsis, acute kidney injury (AKI) and severe malnutrition. After a whole-hospital consultation, the patient was treated with meropenem and vancomycin as antimicrobial therapy, and bilateral nephrostomy drainage was performed simultaneously. After that, the patient suffered a sudden decrease in blood pressure, blood oxygen saturation, and rapid heart rate. Septic shock with multiple organ dysfunction was considered, and she was transferred to intensive care unit (ICU) immediately. After the patient was transferred to ICU, emergency tracheal intubation and ventilator-assisted ventilation were performed. Rapid fluid resuscitation was administered for the patient. While pulse indicator continuous cardiac output (PICCO) monitoring was performed, norepinephrine, terlipressin, and methylene blue were administered to maintain peripheral vascular resistance. Since the patient developed septic cardiomyopathy and cardiogenic shock later, levosimendan and epinephrine were admi-nistered to improve cardiac function. While etiological specimens were delivered, meropenem, teicoplanin and caspofungin were given as initial empiric antimicrobial therapy. Unfortunately, the intrauterine fetal death occurred on the night of admission to ICU. On the 3rd day of ICU admission, a still-born child was delivered vaginally with 1/5 defect of the fetal membrane. On the 6th day of ICU admission, the patient had fever again with elevated inflammatory indicators. After excluding infection in other parts, intrau-terine infection caused by incomplete delivery of fetal membrane was considered. Then emergency uterine curettage was performed and the infection gradually improved. Later the laboratory results showed that the nephrostomy drainage was cultured for Escherichia coli and uterine, cervical and vaginal secretions were cultured for Candida albicans. Due to severe infection and intrauterine incomplete abortion, the patient developed disseminated intravascular coagulation (DIC). Active antimicrobial therapy and blood product supplement were given. However, the patient was critically ill with significant decrease in hemoglobin and platelets combined with multiple organ failure. Thrombotic microangiopathy (TMA) was not excluded yet, so plasma exchange was performed for the patient in order not to delay treatment. The patient underwent bedside continuous renal replacement therapy (CRRT) for AKI. The patient was complicated with acute liver injury, and the liver function gradually returned to normal after liver protection, antimicrobial therapy and other treatments. Due to the application of large doses of vasoactive drugs, the extremities of the patient gradually developed cyanosis and ischemic necrosis. Local dry gangrene of the bilateral toes remained at the time of discharge. In general, the patient suffered from septic shock, cardiogenic shock, combined with DIC and multiple organ dysfunction. After infection source control, antimicrobial therapy, uterine curettage, blood purification treatment, nutritional and metabolic support, the patient was discharged with a better health condition.

Blue Hopes, Red Flags: The Methylene Blue Dilemma in Sepsis Shock

How to cite this article: Govil D, Pachisia AV. Blue Hopes, Red Flags: The Methylene Blue Dilemma in Sepsis Shock. Indian J Crit Care Med 2025;29(2):95-97.

Regional readiness for sodium nitrite-induced methemoglobinemia: availability of methemoglobin testing and methylthioninium chloride (methylene blue) stocking in the Upper Midwestern United States

INTRODUCTION

Sodium nitrite is a potent oxidizer, which may precipitate rapidly lethal methemoglobinemia. Prompt diagnosis and treatment may salvage otherwise fatal cases. It is unclear if emergency departments are prepared for increasing cases. We describe the availability and geographic distribution of real-time methemoglobin testing and methylthioninium chloride (methylene blue) availability in three contiguous United States.

METHODS

This is a cross-sectional survey of hospitals served by a regional poison center in the Upper Midwestern United States. Hospitals were identified by cross-referencing poison center, health department, and state trauma databases. We queried methemoglobin testing capabilities of each site as well as immediate methylthioninium chloride availability. Resulting data are described with descriptive statistics, and predictors of testing and treatment availability are evaluated in multivariable logistic regression.

RESULTS

We identified 320 hospitals with emergency care, analyzing 228 (71.3%) after exclusions. Real-time methemoglobin testing was available at 56 sites (30.6% of 183 respondents). Of hospitals describing methylthioninium chloride availability, 59.4% (130/219) reported having it on-site. A significant difference in real-time methemoglobin testing existed across largest and smallest population strata in adjusted analysis (OR: 64.6: 95% CI: 4.1-1,037). Similarly disparate availability of methylthioninium chloride was observed. Spatial distribution of methemoglobin testing and methylthioninium chloride availability demonstrated notable urban-rural disparities.

DISCUSSION

These data demonstrate a wide disparity in the availability of real-time methemoglobin testing and methylthioninium chloride availability, suggesting that the region is ill-prepared to care for severe methemoglobinemia. Our analysis points to a disconnect between our current poison center recommendations and the capacities of our consulting institutions.

CONCLUSIONS

We demonstrate urban-rural disparities in diagnostic and therapeutic capacity for the management of acute methemoglobinemia in this region, as well as significant geographic variations in methylthioninium chloride stocking and poisoning preparedness. Poison centers must therefore maintain an awareness of antidote availability for this emerging toxicological emergency.

Effects of Early Use of Methylene Blue and Vasopressin on Noradrenaline Dose in Septic Shock: A Randomized Controlled Trial

BACKGROUND

This study aimed to assess the influence of early administration of methylene blue (MB) and vasopressin on the dose of noradrenaline required to manage septic shock.

MATERIALS AND METHODS

This study was a parallel, randomized, controlled trial including 74 adult patients with septic shock admitted to the intensive care unit (ICU). Once the noradrenaline requirement exceeded 0.2 µg/kg/min, patients were randomly allotted to group M and group V. Group M received an intravenous 1 mg/kg bolus of MB over 30 minutes, then an infusion of 0.5 mg/kg over 6 hours. Group V received intravenous vasopressin at a rate of 0.04 units/min for 6 hours. The primary outcome of this research was the dose of noradrenaline required to reach the target mean arterial pressure (MAP) of ≥ 65 mm Hg at 6, 12, and 24 hours. Secondary outcomes included changes in lactate levels, urine output, and sequential organ failure assessment (SOFA) score.

RESULTS

The M group required a higher dose of noradrenaline compared with the V group to maintain MAP above the target level at 12 and 24 hours. There had been no significant variation in lactate levels along with SOFA scores between the two groups at earlier time points. However, at 24 hours, the M group had higher lactate levels and SOFA scores than the V group. The V group also showed improvements in urine output at 24 hours compared with the M group.

CONCLUSION

Early administration of vasopressin compared with MB was associated with a reduced dose of noradrenaline required for maintaining target MAP in patients presenting with septic shock.

HOW TO CITE THIS ARTICLE

Kuri HR, Sharma A, Meshram T, Kothari N, Goyal S, Paliwal B, et al. Effects of Early Use of Methylene Blue and Vasopressin on Noradrenaline Dose in Septic Shock: A Randomized Controlled Trial. Indian J Crit Care Med 2025;29(2):108-112.

Haemodynamic management of septic shock

Septic shock is a significant challenge in the management of patients with burns and traumatic injuries when complicated by infection, necessitating prompt and effective haemodynamic support. This review provides a comprehensive overview of current strategies for vasopressor and fluid management in septic shock, with the aim to optimize patient outcomes. With regard to vasopressor management, we elaborate on the pharmacologic profiles and clinical applications of catecholamines, vasopressin derivatives, angiotensin II, and other vasoactive agents. Noradrenaline remains central to septic shock management. The addition of vasopressin, when sequentially added to noradrenaline, offers a non-catecholaminergic vasoactive effect with some clinical benefits and risks of adverse effects. Emerging agents such as angiotensin II and hydroxocobalamin are highlighted for their roles in catecholamine-resistant vasodilatory shock. Next, for fluid management, crystalloids are currently preferred for initial resuscitation, with balanced crystalloids showing benefits over saline. The application of albumin in septic shock warrants further research. High-quality evidence does not support large-volume fluid resuscitation, and an individualized strategy based on haemodynamic parameters, including lactate clearance and capillary refill time, is recommended. The existing knowledge suggests that early vasopressor initiation, particularly noradrenaline, may be critical in cases where fluid resuscitation takes inadequate effect. Management of refractory septic shock remains challenging, with novel agents like angiotensin II and methylene blue showing potential in recent studies. In conclusion, Further research is needed to optimize haemodynamic management of septic shock, particularly in developing novel vasopressor usage and fluid management approaches.

Systemic inflammatory response index improves prognostic predictive value in intensive care unit patients with sepsis

Sepsis is a severe infectious disease with high mortality. However, the indicators used to evaluate its severity and prognosis are relatively complicated. The systemic inflammatory response index (SIRI), a new inflammatory indicator, has shown good predictive value in chronic infection, stroke, and cancer. The purpose of this study was to investigate the connection between sepsis and SIRI and evaluate its predictive usefulness. A total of 401 patients with sepsis were included in this study. Multiple linear regression and logistic regression analyses were performed to evaluate the relationship between SIRI and sepsis. The restricted cubic spline (RCS) method was employed to illustrate the dose-response relationship. The area under the curve (AUC) and decision curve analysis (DCA) were used to evaluate the prognostic value of SIRI. Multiple linear regression analysis revealed a significant positive correlation between SIRI and both blood cell count and Sequential Organ Failure Assessment (SOFA) score. Additionally, higher SIRI levels were significantly linked to a higher risk of sepsis worsening, according to logistic regression analysis. The RCS curve demonstrated that the risk of poor prognosis rose with increasing SIRI, particularly when SIRI exceeded 6.1. Furthermore, AUC and DCA results showed that SIRI had superior predictive value compared to traditional indicators. A higher SIRI is linked to a worse prognosis and more severe sepsis. SIRI may serve as a novel prognostic indicator in sepsis, though further clinical studies are necessary to confirm these findings.

Comparative study between high and low dose methylene blue infusion in septic cancer patients: a randomized, blinded, controlled study

PURPOSE

Septic shock is a common threat, and is the primary cause of death in almost all critical care units. Mortality of septic shock remains exceedingly high. The early use of methylene blue (MB) in different doses as adjunctive to vasopressors has promising results.

METHODS

This double-blind, randomized, controlled trial comprised 90 patients divided into 3 groups: Group A received a 100 ml 0.9% NaCl placebo over 20 min; Group B received an MB bolus of 1 mg/kg in 100 ml 0.9% NaCl, and Group C received MB bolus of 4 mg/kg in 100 ml 0.9% NaCl during the same period. Groups B and C were given a 0.25 mg/kg/hour infusion of MB for 72 h after the bolus dose. All patients were started on noradrenaline at an infusion rate of 0.1-0.2 µ/kg/min and were adjusted accordingly to maintain MAP ≥ 65 mmHg. Time of vasopressor discontinuation was the primary outcome while total doses of vasopressors, ventilation days, vasopressors free days, total ICU stay, total hospital stay, and mortality rate were the secondary outcomes.

RESULTS

Groups B and C exhibited significantly decreased time to vasopressor termination, and vasopressor-free days at 28 days in comparison to Group A. However, there was no significant difference between Groups B and C. Groups B and C had significantly lower noradrenaline dosages compared to Group A, however, no significant difference between Group B and Group C was found. The difference between the three groups in mortality rate was near statistical significance (p = 0.083). Using the logistic regression model, the 4 mg/kg group was protective against mortality with a hazard ratio of 0.29 (95%CI: 0.09-0.90).

CONCLUSION

In cancer patients with septic shock, early adjunctive MB delivery reduces the time to a vasopressor stoppage and increases the vasopressor-free days. No significant difference between high and low MB bolus doses, and no significant adverse effects were noted. Compared to placebo, the 4 mg/kg bolus dose shows a survival advantage.

TRIAL REGISTRATION

Prospectively registered at clinicaltrials.gov [NCT06005558]. (Date of registration 15/08/2023).

The use of methylene blue in adult patients with septic shock: a systematic review and meta-analysis

OBJECTIVES

Methylene blue exerts its vasopressor properties by inhibiting nitric oxide-mediated vasodilation. Recent studies have advocated the use of methylene blue as a rescue therapy for patients with septic shock. The primary aim was to investigate the effect of methylene blue on the mean arterial pressure among adult patients with septic shock.

METHODS

Databases of MEDLINE, EMBASE, and CENTRAL were searched from their inception date until October 2023. Randomized Clinical Trials (RCT) comparing methylene blue and placebo in adults with septic shock were included.

RESULTS

Our systematic review included 5 studies (n = 257) for data analysis. As compared to the placebo, our pooled analysis showed that methylene blue significantly increased mean arterial pressure (MD: 1.34 mmHg, 95% CI 0.15 to 2.53, p = 0.03, level of evidence: very low). Patients who were given methylene blue were associated with statistically lower mortality rate (OR = 0.49, 95% CI 0.27 to 0.88, p = 0.02, level of evidence: low), reduced serum lactate levels (MD: -0.76 mmoL.L-1, 95% CI -1.22 to -0.31, p = 0.0009, level of evidence: low), reduced length of hospital stay (MD: -1.94 days, 95% CI -3.79 to -0.08, p = 0.04, level of evidence: low), and increased PaO2/FiO2 (MD: 34.78, 95% CI 8.94 to 60.61, p = 0.008, level of evidence: low).

CONCLUSIONS

This meta-analysis demonstrated that methylene blue administration was associated with an increased in mean arterial pressure and PaO2/FiO2 ratio, along with a reduction in mortality rates, serum lactate levels, and length of hospital stay. However, substantial degree of heterogeneity and inadequate number of studies with low level of evidence warrant future adequately powered RCTs to affirm our results.

Non-adrenergic vasopressors for vasodilatory shock or perioperative vasoplegia: a meta-analysis of randomized controlled trials

BACKGROUND

Excessive exposure to adrenergic vasopressors may be harmful. Non-adrenergic vasopressors may spare adrenergic agents and potentially improve outcomes. We aimed to conduct a systematic review and meta-analysis of randomized controlled trials (RCTs) to evaluate the efficacy of non-adrenergic vasopressors in adult patients receiving vasopressor therapy for vasodilatory shock or perioperative vasoplegia.

METHODS

We searched PubMed, Embase, and Cochrane Library for RCTs comparing non-adrenergic vasopressors with adrenergic vasopressors alone or placebo in critically ill or perioperative patients. Each eligible study was categorized into septic shock, cardiac surgery, or non-cardiac surgery. Non-adrenergic vasopressors included vasopressin, terlipressin, selepressin, angiotensin II, methylene blue, and hydroxocobalamin. The primary outcome was mortality at longest follow-up. We conducted a random-effects meta-analysis. We registered the protocol in PROSPERO International Prospective Register of Systematic Reviews (CRD42024505039).

RESULTS

Among 51 eligible RCTs totaling 5715 patients, the predominant population was septic shock in 30 studies, cardiac surgery in 11 studies, and non-cardiac surgery in 10 studies. Cochrane risk-of-bias tool for randomized trials version 2 identified 17 studies as low risk of bias. In septic shock, mortality was significantly lower in the non-adrenergic group (960/2232 [43%] vs. 898/1890 [48%]; risk ratio [RR], 0.92; 95% confidence interval [95% CI], 0.86-0.97; P = 0.03; I2 = 0%), with none of the individual non-adrenergic vasopressors showing significant survival benefits. No significant mortality difference was observed in patients undergoing cardiac surgery (34/410 [8.3%] vs. 47/412 [11%]; RR, 0.82; 95% CI, 0.55-1.22; P = 0.32; I2 = 12%) or those undergoing non-cardiac surgery (9/388 [2.3%] vs. 18/383 [4.7%]; RR, 0.66; 95% CI, 0.31-1.41; P = 0.28; I2 = 0%).

CONCLUSIONS

Administration of non-adrenergic vasopressors was significantly associated with reduced mortality in patients with septic shock. However, no single agent achieved statistical significance in separate analyses. Although the pooled effects of non-adrenergic vasopressors on survival did not reach statistical significance in patients undergoing cardiac or non-cardiac surgery, the confidence intervals included the possibility of both no effect and a clinically important benefit from non-adrenergic agents. These findings justify the conduct of further RCTs comparing non-adrenergic vasopressors to usual care based on noradrenaline alone.

Vasopressor Therapy

Vasopressor therapy represents a key part of intensive care patient management, used to increase and maintain vascular tone and thus adequate tissue perfusion in patients with shock. Norepinephrine is the preferred first-line agent because of its reliable vasoconstrictor effects, with minimal impact on heart rate, and its mild inotropic effects, helping to maintain cardiac output. Whichever vasopressor is used, its effects on blood flow must be considered and excessive vasoconstriction avoided. Other vasoactive agents include vasopressin, which may be considered in vasodilatory states, and angiotensin II, which may be beneficial in patients with high renin levels, although more data are required to confirm this. Dobutamine should be considered, along with continued fluid administration, to help maintain adequate tissue perfusion in patients with reduced oxygen delivery. In this narrative review, we consider the different vasopressor agents, focusing on the importance of tailoring therapy to the individual patient and their hemodynamic response.

Methylene blue therapy in addition to standard treatment for acute-phase septic shock: a pilot randomized controlled trial

Purpose

Methylene blue (MB) has been used to increase blood pressure in patients with septic shock by acting on guanylate cyclase and nitric oxide synthase.

Objective

To determine whether the administration of MB to patients in the initial phase of septic shock leads to a reduction in the use of vasopressors compared to the Control group.

Methods

This was a 1:1 randomized clinical trial of two groups (MB and Control). Forty-two patients were included in the present study; 23 patients were allocated to the Control group, and 19 were randomized to the MB group. Both groups had access to standard treatment, consisting of fluid replacement, vasopressors, and antibiotic therapy. Patients received a loading dose of MB (3 mg/kg) and maintenance (0.5 mg/kg/h) for 48 h. Vasopressor doses, laboratory test results, inflammatory and anti-inflammatory cytokine levels, and hemodynamic monitoring were recorded before the infusion of MB (T1) and after 20 min (T2), 2 h (T3), 24 h (T4), 48 h after the infusion started (T5) and 24 h after weaning (T6).

Results

MB therapy was started together with the indication of vasopressin (VAS) as a second vasopressor. The MB group showed an immediate reduction in NOR dosage, an earlier reduction in VAS dosage, and higher IL-10 levels compared to the Control group.

Conclusion

Early administration of MB in combination with standard treatment for septic shock might be reduce vasopressors dose. Continuous infusion of MB for 48 h was considered safe and there was no adverse events. These results highlight the potential of MB as a safe adjuvant therapeutic option in the treatment of septic shock.

Clinical trial registration

https://clinicaltrials.gov/, identifier RBR-96584w4.

Major Publications in the Critical Care Pharmacotherapy Literature: 2023

OBJECTIVES

We aimed to summarize the most significant and impactful publications describing the pharmacotherapeutic care of critically ill patients in 2023.

DATA SOURCES

PubMed/MEDLINE and the Clinical Pharmacy and Pharmacology Pharmacotherapy Literature Update.

STUDY SELECTION

Randomized controlled trials and prospective studies of adult critically ill patients assessing a pharmacotherapeutic intervention and reporting clinical endpoints published between January 1, 2023, and December 31, 2023, were eligible for inclusion in this article.

DATA EXTRACTION

Articles from a systematic search and the Clinical Pharmacy and Pharmacology Pharmacotherapy Literature Update were included. An a priori defined three-round modified Delphi process was employed to achieve consensus on the most impactful publications based on the following considerations: 1) overall contribution to scientific knowledge and 2) novelty to the literature.

DATA SYNTHESIS

The systematic search and Clinical Pharmacy and Pharmacology Pharmacotherapy Literature Update returned a total of 1202 articles, of which 1164 were excluded. The remaining 38 articles underwent a three-round modified Delphi process. In each round, articles were independently scored based on overall contribution to scientific knowledge and novelty to the literature. Included articles are summarized and their impact discussed. Article topics included hydrocortisone for severe community-acquired pneumonia, inhaled amikacin for prevention of ventilator-associated pneumonia, methylene blue for septic shock, restrictive vs. liberal fluid management for sepsis-induced hypotension, andexanet alfa for major bleeding associated with factor Xa inhibitors, and early administration of four-factor prothrombin complex concentrate in patients with trauma at risk for massive transfusion.

CONCLUSIONS

This review provides a summary and perspective on the potential impact of the most relevant articles in 2023 describing advances in the pharmacotherapeutic care of critically ill patients.

Efficacy of methylene blue in refractory septic shock: study protocol for a multicenter, randomized, placebo-controlled trial

BACKGROUND

Septic shock is now the leading cause of mortality in intensive care units (ICUs). Refractory septic shock requires high doses of vasopressors. Some previous studies have revealed that methylene blue could improve hypotension status and help reduce the dosage of catecholamines. This study aims to investigate the clinical effect of methylene blue in septic shock and explore whether it can increase arterial pressure and reduce the usage of vasopressors.

METHODS

This study is a multicenter, randomized, placebo-controlled trial planning to include 100 refractory septic shock patients. The protocol is to administer a bolus of 2 mg/kg methylene blue intravenously followed by a continuous infusion of 0.5 mg/kg/h for 48 h. The primary outcome is the total dose of vasopressor required in refractory septic shock in the first 48 h. Secondary outcomes include other hemodynamic parameters, oxygen metabolism indexes, tissue perfusion indexes, major organ function indexes, and certain plasma cytokines and other factors.

DISCUSSION

This protocol aims to evaluate the safety and efficacy of methylene blue as adjuvant therapy for refractory septic shock. The main outcome measure will be vasopressor requirements and hemodynamic parameters. Additionally, bedside ultrasonography, blood gases, and cytokines will be assessed to evaluate perfusion, respiratory, and metabolic effects. The results are intended to provide evidence on the safety and efficacy of methylene blue in refractory septic shock, guiding clinical decision-making.

TRIAL REGISTRATION

This clinical trial has been registered at ChiCTR ( https://www.chictr.org.cn/ ) on March 16, 2023. ChiCTR registration number: ChiCTR2300069430.

Blood Pressure Management for Hypotensive Patients in Intensive Care and Perioperative Cardiovascular Settings

Blood pressure is a critical physiological parameter, particularly in the context of cardiac intensive care and perioperative settings. As a primary indicator of organ perfusion, the maintenance of adequate blood pressure is imperative for the assurance of sufficient tissue oxygen delivery. Among critically ill and major surgery patients, the continuous monitoring of blood pressure is performed as a standard practice for patients. Nonetheless, uncertainties remain regarding blood pressure goals, and there is no consensus regarding blood pressure targets. This review describes the determinants of blood pressure, examine the influence of blood pressure on organ perfusion, and synthesize the current clinical evidence from various intensive care and perioperative settings to provide a concise guidance for daily clinical practice.

Haemophagocytic lymphohistiocytosis (HLH) secondary to disseminated histoplasmosis infection in a patient with HIV

A male in his 30s who was recently diagnosed with HIV arrived at the emergency department exhibiting an altered mental state and acute respiratory distress. Initial laboratory tests revealed a high anion gap metabolic acidosis, elevated liver enzyme levels and bicytopenia. A CT scan identified a miliary pattern. Bronchoscopy with bronchoalveolar lavage displayed epithelial and inflammatory cells. However, subsequent tests ruled out the presence of fungi, Pneumocystis organisms, malignancies, granulomas and viral inclusions. Broad-spectrum antibiotics with emphasis on Mycobacterium tuberculosis and antifungal treatments were administered. The regimen was adjusted after a positive urine test for the Histoplasma antigen.The patient later manifested signs and symptoms, including increased ferritin level, fever, splenomegaly, diminished natural killer cell function and heightened interleukin-2 receptor levels, confirming haemophagocytic lymphohistiocytosis. Given the patient's gravely decompensated state, the treatment incorporated dexamethasone, and the patient's vasopressor-resistant septic shock was addressed with methylene blue.

Angiotensin II as a Vasopressor for Perioperative Hypotension in Solid Organ Transplant

During the perioperative period of transplantation, patients experience hypotension secondary to the side effects of anesthesia, surgical stress, inflammatory triggering, and intraoperative fluid shifts, among others causes. Vasopressor support, in this context, must reverse systemic hypotension, but ideally, the agents used should benefit allograft function and avoid the adverse events commonly seen after transplantation. Traditional therapies to reverse hypotension include catecholamine vasopressors (norepinephrine, epinephrine, dopamine, and phenylephrine), but their utility is limited when considering allograft complications and adverse events such as arrhythmias with agents with beta-adrenergic properties. Synthetic angiotensin II (AT2S-[Giapreza]) is a novel vasopressor indicated for distributive shock with a unique mechanism of action as an angiotensin receptor agonist restoring balance to an often-disrupted renin angiotensin aldosterone system. Additionally, AT2S provides a balanced afferent and efferent arteriole vasoconstriction at the level of the kidney and could avoid the arrhythmic complications of a beta-adrenergic agonist. While the data, to date, are limited, AT2S has demonstrated safety in case reports, pilot studies, and small series in the kidney, liver, heart, and lung transplant populations. There are physiologic and hemodynamic reasons why AT2S could be a more utilized agent in these populations, but further investigation is warranted.

Efficacy and safety of dynamic arterial elastance for weaning vasopressor support in septic shock patients: a randomised controlled trial protocol

INTRODUCTION

The dynamic arterial elastance (EaDyn), calculated as pulse pressure variation divided by stroke volume variation, has been studied as a predictor of vasopressor weaning. However, its potential as a haemodynamic tool for tapering off vasopressors in patients with sepsis remains unexplored. Therefore, our study aimed to assess whether using EaDyn for weaning vasopressor support could reduce the duration of vasopressor support in patients with sepsis.

METHODS AND ANALYSIS

This pragmatic single-centre controlled clinical trial will take place at Fundación Santa Fe de Bogotá, Colombia. Adult patients diagnosed with septic shock according to the sepsis-3 criteria and a Sequential Organ Failure Assessment score ≥4 will be included. A total of 114 patients (57 per group) will undergo conventional critical care monitoring, and the weaning of vasopressor support will be initiated based on the EaDyn or mean arterial pressure (MAP), depending on the assigned group. EaDyn will be estimated based on the measurements obtained from a PiCCO device connected to a PulsioFlex Monitoring Platform (PULSION Medical Systems SE, Feldkirchen, Germany). Our primary outcome is the difference in vasopressor support duration between the EaDyn and MAP groups.Participants and statisticians performing the statistical analysis will be blinded to the group allocation. Dependent and independent variables will be analysed through univariate and multivariate statistical tests. Since we will perform three repeated measurements for analysis, we will implement a Bonferroni post hoc correction. Additionally, Cox regression and Kaplan-Meier analyses will be conducted to address objectives related to time.

ETHICS AND DISSEMINATION

This study was approved by the Ethics Committee at Fundación Santa Fe de Bogotá (CCEI-16026-2024). Written informed consent will be obtained from all participants. The results will be disseminated through publication in peer-reviewed journals and presentations at national and international events.

TRIAL REGISTRATION NUMBER

NCT06118775.

Methylene Blue in Septic Shock: A Systematic Review and Meta-Analysis

OBJECTIVES

Although clinicians may use methylene blue (MB) in refractory septic shock, the effect of MB on patient-important outcomes remains uncertain. We conducted a systematic review and meta-analysis to investigate the benefits and harms of MB administration in patients with septic shock.

DATA SOURCES

We searched six databases (including PubMed, Embase, and Medline) from inception to January 10, 2024.

STUDY SELECTION

We included randomized clinical trials (RCTs) of critically ill adults comparing MB with placebo or usual care without MB administration.

DATA EXTRACTION

Two reviewers performed screening, full-text review, and data extraction. We pooled data using a random-effects model, assessed the risk of bias using the modified Cochrane tool, and used Grading of Recommendations Assessment, Development, and Evaluation to rate certainty of effect estimates.

DATA SYNTHESIS

We included six RCTs (302 patients). Compared with placebo or no MB administration, MB may reduce short-term mortality (RR [risk ratio] 0.66 [95% CI, 0.47-0.94], low certainty) and hospital length of stay (mean difference [MD] -2.1 d [95% CI, -1.4 to -2.8], low certainty). MB may also reduce duration of vasopressors (MD -31.1 hr [95% CI, -16.5 to -45.6], low certainty), and increase mean arterial pressure at 6 hours (MD 10.2 mm Hg [95% CI, 6.1-14.2], low certainty) compared with no MB administration. The effect of MB on serum methemoglobin concentration was uncertain (MD 0.9% [95% CI, -0.2% to 2.0%], very low certainty). We did not find any differences in adverse events.

CONCLUSIONS

Among critically ill adults with septic shock, based on low-certainty evidence, MB may reduce short-term mortality, duration of vasopressors, and hospital length of stay, with no evidence of increased adverse events. Rigorous randomized trials evaluating the efficacy of MB in septic shock are needed.

REGISTRATION

Center for Open Science (https://osf.io/hpy4j).

Methylene blue in sepsis and septic shock: a systematic review and meta-analysis

Background

Methylene blue is an interesting approach in reducing fluid overload and vasoactive drug administration in vasodilatory shock. The inhibition of guanylate cyclase induced by methylene blue infusion reduces nitric oxide production and improves vasoconstriction. This systematic review and meta-analysis aimed to assess the effects of methylene blue administration compared to placebo on the hemodynamic status and clinical outcomes in patients with sepsis and septic shock.

Methods

The authors specifically included randomized controlled trials that compared the use of methylene blue with placebo in adult patients with sepsis and septic shock. The outcomes were length of intensive care unit stay, hemodynamic parameters [vasopressor use], and days on mechanical ventilation. We also evaluated the abnormal levels of methemoglobinemia. This systematic review and meta-analysis were recorded in PROSPERO with the ID CRD42023423470.

Results

During the initial search, a total of 1,014 records were identified, out of which 393 were duplicates. Fourteen citations were selected for detailed reading, and three were selected for inclusion. The studies enrolled 141 patients, with 70 of them in the methylene blue group and 71 of them in the control group. Methylene blue treatment was associated with a lower length of intensive care unit stay (MD -1.58; 95%CI -2.97, -0.20; I2 = 25%; p = 0.03), decreased days on mechanical ventilation (MD -0.72; 95%CI -1.26, -0.17; I2 = 0%; p = 0.010), and a shorter time to vasopressor discontinuation (MD -31.49; 95%CI -46.02, -16.96; I2 = 0%; p < 0.0001). No association was found with methemoglobinemia.

Conclusion

Administering methylene blue to patients with sepsis and septic shock leads to reduced time to vasopressor discontinuation, length of intensive care unit stay, and days on mechanical ventilation.

Systematic review registration

https://www.crd.york.ac.uk/prospero/display_record.php?ID=CRD42023423470, CRD42023423470.

Refractory circulatory failure in COVID-19 patients treated with veno-arterial ECMO a retrospective single-center experience

OBJECTIVE

In this retrospective case series, survival rates in different indications for veno-arterial extracorporeal membrane oxygenation (VA-ECMO) and differential diagnoses of COVID-19 associated refractory circulatory failure are investigated.

METHODS

Retrospective analysis of 28 consecutive COVID-19 patients requiring VA-ECMO. All VA-ECMO's were cannulated peripherally, using a femoro-femoral cannulation.

RESULTS

At VA-ECMO initiation, median age was 57 years (IQR: 51-62), SOFA score 16 (IQR: 13-17) and norepinephrine dosing 0.53μg/kg/min (IQR: 0.35-0.87). Virus-variants were: 61% wild-type, 14% Alpha, 18% Delta and 7% Omicron. Indications for VA-ECMO support were pulmonary embolism (PE) (n = 5, survival 80%), right heart failure due to secondary pulmonary hypertension (n = 5, survival 20%), cardiac arrest (n = 4, survival 25%), acute heart failure (AHF) (n = 10, survival 40%) and refractory vasoplegia (n = 4, survival 0%). Among the patients with AHF, 4 patients suffered from COVID-19 associated heart failure (CovHF) (survival 100%) and 6 patients from sepsis associated heart failure (SHF) (survival 0%). Main Complications were acute kidney injury (AKI) 93%, renal replacement therapy was needed in 79%, intracranial hemorrhage occurred in 18%. Overall survival to hospital discharge was 39%.

CONCLUSION

Survival on VA-ECMO in COVID-19 depends on VA-ECMO indication, which should be considered in further studies and clinical decision making. A subgroup of patients suffers from acute heart failure due to inflammation, which has to be differentiated into septic or COVID-19 associated. Novel biomarkers are required to ensure reliable differentiation between these entities; a candidate might be soluble interleukin 2 receptor.

Treatment of refractory shock with vitamin B12 : A narrative review

High-dose vitamin B12 is a potential treatment for patients with vasodilatory shock that is refractory to other therapies. Vasodilatory shock is characterized by low blood pressure and low systemic vascular resistance. Nitric oxide and hydrogen sulfide, two potential targets of high-dose vitamin B12 given as hydroxocobalamin, facilitate this syndrome. This review explores the relationship between high-dose vitamin B12 and hemodynamic outcomes in adults with vasodilatory shock and provides an update on the literature since a 2019 review on this topic. A literature search of studies published in the past 5 years was conducted in the CINAHL, PubMed, Cochrane, and EMBASE databases in May 2023. After assessing for eligibility, eight studies met this review's inclusion criteria. Seven of the eight studies reported decreased vasopressor requirements for part or all of the study samples after receiving a hydroxocobalamin infusion. However, not all patients responded to hydroxocobalamin. These findings are limited by patient selection and differences in the timing of vasopressor requirement and blood pressure outcome assessments. The current evidence is promising as to whether vitamin B12 , given as a hydroxocobalamin infusion, may improve hemodynamic outcomes in vasodilatory shock, but the evidence is of low quality. The use of hydroxocobalamin to treat refractory, vasodilatory shock remains investigative. Larger randomized controlled trials are required to elucidate the role of vitamin B12 in treating refractory, vasodilatory shock, including in conjunction with other alternative therapies such as methylene blue and corticosteroids.

Spectrophotometric analysis of purple urine secondary to methylene blue and hydroxocobalamin co-administration

BACKGROUND

The development of purple urine after methylene blue (methylthioninium chloride) and hydroxocobalamin co-administration is a rare clinical entity that has not been fully elucidated. A 47-year-old male presented to the emergency department with hypotension, cyanosis, and depressed mental status. The patient was noted to have profound peripheral and central cyanosis, as well as chocolate-colored arterial blood. He was treated with both methylene blue and hydroxocobalamin and developed purple urine for approximately 1 week.

METHODS

Color chromatography was performed by placing the patient's urine directly onto absorbent filter paper. Urine spectrophotometry was performed utilizing the NanoDrop One/One C UV-Vis Spectrophotometer.

RESULTS

Color chromatography of the urine was demonstrated clear separation of distinct red and blue phases. Urine spectrophotometry demonstrated near perfect overlap between the methylene blue + hydroxocobalamin absorbance spectrum and the patient's purple urine absorbance spectrum.

CONCLUSION

Purple urine secondary to methylene blue and hydroxocobalamin co-administration is due to combined urinary excretion of methylene blue (blue) and hydroxocobalamin (red), and not a novel purple metabolite. We anticipate that this is going to be an increasingly common clinical entity as the roles of both hydroxocobalamin and methylene blue expand from toxicologic antidotes to adjunct therapies for vasoplegia, poor cardiac output, and sepsis.

Administration of methylene blue in septic shock: pros and cons

Septic shock typically requires the administration of vasopressors. Adrenergic agents remain the first choice, namely norepinephrine. However, their use to counteract life-threatening hypotension comes with potential adverse effects, so that non-adrenergic vasopressors may also be considered. The use of agents that act through different mechanisms may also provide an advantage. Nitric oxide (NO) is the main driver of the vasodilation that leads to hypotension in septic shock, so several agents have been tested to counteract its effects. The use of non-selective NO synthase inhibitors has been of questionable benefit. Methylene blue, an inhibitor of soluble guanylate cyclase, an important enzyme involved in the NO signaling pathway in the vascular smooth muscle cell, has also been proposed. However, more than 25 years since the first clinical evaluation of MB administration in septic shock, the safety and benefits of its use are still not fully established, and it should not be used routinely in clinical practice until further evidence of its efficacy is available.

Effect of methylene blue on outcomes in patients with distributive shock: a meta-analysis of randomised controlled trials

OBJECTIVE

This meta-analysis aimed to demonstrate the effect of methylene blue (MB) in patients with distributive shock.

DESIGN

Meta-analysis.

METHODS

According to the Prospective International Register of Systematic Reviews (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines, we searched the relevant randomised controlled trials (RCTs) via PubMed, Embase and Cochrane Library from the date of database inception to 19 April 2023. The primary outcome was mortality during follow-up, and secondary outcomes included mean arterial pressure (mm Hg), mechanical ventilation time (hours), intensive care unit (ICU) length of stay (LOS) (days), hospital LOS (days) and heart rate (times/min).

RESULTS

This study included six RCTs with 265 participants. The study showed no significant difference in mortality between the MB and placebo groups (ORs: 0.59; 95% CI 0.32 to -1.06). However, MB reduced the duration of mechanical ventilation (mean difference (MD): -0.68; 95% CI -1.23 to -0.14), ICU LOS (MD: -1.54; 95% CI -2.61 to -0.48) and hospital LOS (MD: -1.97; 95% CI -3.92 to -0.11).

CONCLUSIONS

The use of MB may not reduce mortality in patients with distributive shock, but may shorten the duration of mechanical ventilation, ICU LOS and hospital LOS. More clinical studies are needed to confirm these findings in the future.

TRIAL REGISTRATION NUMBER

CRD42023415938.

Author Response

How to cite this article: Rajbanshi LK, Arjyal B. Author Response. Indian J Crit Care Med 2024;28(1):90-91.

Methylene Blue Reduces Mortality in Critically Ill and Perioperative Patients: A Meta-Analysis of Randomized Trials

Vasodilatory hypotension is common in critically ill and perioperative patients, and is associated with adverse outcomes. As a nitric oxide production inhibitor, methylene blue (MB) exerts its vasoconstrictor property and is an adjuvant for catecholamine-refractory vasodilatory shock. However, the effects of MB on clinically relevant outcomes remain unclear. Therefore, the authors performed a meta-analysis of randomized trials on MB in critically ill and perioperative patients. The authors searched through databases for randomized trials on MB in critically ill and perioperative patients, which yielded 11 studies consisting of 556 patients. The primary outcome was mortality at the longest follow-up. Secondary outcomes included hemodynamic parameters and organ dysfunction (PROSPERO: CRD42023409243). Nine out of the 11 included randomized trials reported mortality, which was significantly lower in the MB group (risk ratio, 0.60 [95% CI 0.43-0.84] p = 0.003), with findings confirmed in septic shock and cardiac surgery subgroups. The authors found reduced lengths of stay in the intensive care unit (mean difference [MD], -0.9 days [95% CI -1.06 to -0.77] p < 0.001) and in the hospital (MD, -2.2 days [95% CI, -2.68 to -1.70] p < 0.001) in the MB group. MB was associated with increased mean arterial pressure (MD, 8.4 mmHg [95% CI 5.01-11.75] p < 0.001) and systemic vascular resistance (MD, 94.5 dyn/s/cm5 [95% CI 17.73-171.15] p = 0.02), with no difference in cardiac output (standardized MD, 0.16 [95% CI, -0.25 to 0.57] p = 0.45). This meta-analysis showed that MB reverses vasodilation in critically ill and perioperative patients and might improve survival. Further adequately powered randomized trials are needed to confirm these findings.

The effects of methylene blue during and after cardiac arrest in a porcine model; a randomized, blinded, placebo-controlled study

PURPOSE

To evaluate the effect of methylene blue administered as a bolus on return of spontaneous circulation (ROSC), lactate levels, vasopressor requirements, and markers of neurological injury in a clinically relevant pig model of cardiac arrest.

MATERIALS AND METHODS

40 anesthetized pigs were subjected to acute myocardial infarction and 7 min of untreated cardiac arrest. Animals were randomized into three groups: one group received saline only (controls), one group received 2 mg/kg methylene blue and saline (MB + saline), and one group received two doses of 2 mg/kg methylene blue (MB + MB). The first intervention was given after the 3rd rhythm analysis, while the second dose was administered one hour after achieving ROSC. Animals underwent intensive care and observation for six hours, followed by cerebral magnetic resonance imaging (MRI). The primary outcome for this study was development in lactate levels after cardiac arrest. Categorical data were compared using Fisher's exact test and pointwise data were analyzed using one-way analysis of variance (ANOVA) or equivalent non-parametric test. Continuous data collected over time were analyzed using a linear mixed effects model. A value of p < .05 was considered statistically significant.

RESULTS

Lactate levels increased in all groups after cardiac arrest and resuscitation, however lactate levels in the MB + MB group decreased significantly faster compared with the control group (p = .007) and the MB + saline group (p = .02). The proportion of animals achieving initial ROSC was similar across groups: 11/13 (85%) in the control group, 10/13 (77%) in the MB + saline group, and 12/14 (86%) in the MB + MB group (p = .81). Time to ROSC did not differ between groups (p = .67). There was no significant difference in accumulated norepinephrine dose between groups (p = .15). Cerebral glycerol levels were significantly lower in the MB + MB group after resuscitation compared with control group (p = .03). However, MRI data revealed no difference in apparent diffusion coefficient, cerebral blood flow, or dynamic contrast enhanced MR perfusion between groups.

CONCLUSION

Treatment with a bolus of methylene blue during cardiac arrest and after resuscitation did not significantly improve hemodynamic function. A bolus of methylene blue did not yield the neuroprotective effects that have previously been described in animals receiving methylene blue as an infusion.

The Eight Unanswered and Answered Questions about the Use of Vasopressors in Septic Shock

Septic shock is mainly characterized-in addition to hypovolemia-by vasoplegia as a consequence of a release of inflammatory mediators. Systemic vasodilatation due to depressed vascular tone results in arterial hypotension, which induces or worsens organ hypoperfusion. Accordingly, vasopressor therapy is mandatory to correct hypotension and to reverse organ perfusion due to hypotension. Currently, two vasopressors are recommended to be used, norepinephrine and vasopressin. Norepinephrine, an α₁-agonist agent, is the first-line vasopressor. Vasopressin is suggested to be added to norepinephrine in cases of inadequate mean arterial pressure instead of escalating the doses of norepinephrine. However, some questions about the bedside use of these vasopressors remain. Some of these questions have been well answered, some of them not clearly addressed, and some others not yet answered. Regarding norepinephrine, we firstly reviewed the arguments in favor of the choice of norepinephrine as a first-line vasopressor. Secondly, we detailed the arguments found in the recent literature in favor of an early introduction of norepinephrine. Thirdly, we reviewed the literature referring to the issue of titrating the doses of norepinephrine using an individualized resuscitation target, and finally, we addressed the issue of escalation of doses in case of refractory shock, a remaining unanswered question. For vasopressin, we reviewed the rationale for adding vasopressin to norepinephrine. Then, we discussed the optimal time for vasopressin administration. Subsequently, we addressed the issue of the optimal vasopressin dose, and finally we discussed the best strategy to wean these two vasopressors when combined.

Successful Use of Methylene Blue in Catecholamine-Resistant Septic Shock: A Case Report and Short Literature Review

Despite efforts to improve treatment outcomes, mortality in septic shock remains high. In some patients, despite the use of several adrenergic drugs, features of refractory vasoplegic shock with progressive multiorgan failure are observed. We present a case report of the successful reversal of vasoplegic shock following the use of methylene blue, a selective inhibitor of the inducible form of nitric oxide synthase, which prevents vasodilation in response to inflammatory cytokines. We also briefly review the literature.