Methylene blue for the treatment of refractory anaphylaxis without hypotension

Effect of Nitric Oxide Pathway Inhibition on the Evolution of Anaphylactic Shock in Animal Models: A Systematic Review

Simple Summary

Anaphylactic shock (AS) is the most serious consequence of anaphylaxis, with life-threatening sequelae including hypovolemia, shock, and arrhythmias. The literature lacks evidence for the effectiveness of interventions other than epinephrine in the acute phase of anaphylaxis. Our objective was to assess, through a systematic review, how inhibition of nitric oxide (NO) pathways affects blood pressure, and whether such blockade improves survival in AS animal models. AS was induced in all included studies after or before drug administration that targeted blockade of the NO pathway. In all animal species studied, the induction of AS caused a reduction in arterial blood pressure. However, the results show different responses to the inhibition of nitric oxide pathways. Overall, seven of fourteen studies using inhibition of nitric oxide pathways as pre-treatment before induction of AS showed improvement of survival and/or blood pressure. Four post-treatment studies from eight also showed positive outcomes. This review did not find strong evidence to propose modulation of blockade of the NO/cGMP pathway as a definitive treatment for AS in humans. Well-designed in vivo AS animal pharmacological models are needed to explore the other pathways involved, supporting the concept of pharmacological modulation.

Abstract

Nitric oxide (NO) induces vasodilation in various types of shock. The effect of pharmacological modulation of the NO pathway in anaphylactic shock (AS) remains poorly understood. Our objective was to assess, through a systematic review, whether inhibition of NO pathways (INOP) was beneficial for the prevention and/or treatment of AS. A predesigned protocol for this systematic review was published in PROSPERO (CRD42019132273). A systematic literature search was conducted till March 2022 in the electronic databases PubMed, EMBASE, Scopus, Cochrane and Web of Science. Heterogeneity of the studies did not allow meta-analysis. Nine hundred ninety unique studies were identified. Of 135 studies screened in full text, 17 were included in the review. Among six inhibitors of NO pathways identified, four blocked NO synthase activity and two blocked guanylate cyclase downstream activity. Pre-treatment was used in nine studies and post-treatment in three studies. Five studies included both pre-treatment and post-treatment models. Overall, seven pre-treatment studies from fourteen showed improvement of survival and/or arterial blood pressure. Four post-treatment studies from eight showed positive outcomes. Overall, there was no strong evidence to conclude that isolated blockade of the NO/cGMP pathway is sufficient to prevent or restore anaphylactic hypotension. Further studies are needed to analyze the effect of drug combinations in the treatment of AS.

Clinical reasoning in anaphylactic shock: addressing the challenges faced by anaesthesiologists in real time: A clinical review and management algorithms

Acute hypersensitivity reactions to drugs occur infrequently during anaesthesia and the peri-operative period. When clinical presentation includes the classical triad, erythema, cardiovascular abnormalities and increased airway pressure, the diagnosis is evident and the challenge is to prescribe a therapeutic regimen according to guidelines and to manage refractory signs in a timely manner. In many situations, however, the initial clinical signs are isolated, such as increased airway pressure or arterial hypotension. Rendering a differential diagnosis with causes and mechanisms other than acute hypersensitivity reactions (AHRs) is difficult, delaying treatment with possible worsening of the clinical signs, and even death, in previously healthy individuals. In these difficult diagnostic situations, clinical reasoning is mandatory, and guidelines do not explicitly explain the elements on which clinical reasoning can be built. In this article, based on clinical evidence whenever available, experimental data and pathophysiology, we propose algorithms that have been evaluated by experts. The goal of these algorithms is to provide explicit elements on which the differential diagnosis of AHRs can be made, accelerating the implementation of adequate therapy.

Critical Care Management of the Patient With Anaphylaxis: A Concise Definitive Review

OBJECTIVES

Anaphylaxis is a rapidly progressive life-threatening syndrome manifesting as pruritus, urticaria, angioedema, bronchospasm and shock. The goal of this synthetic review is to provide a practical, updated approach to the evaluation and management of this disorder and associated complications.

DATA SOURCES

A MEDLINE search was conducted with the MeSH of anaphylaxis, anaphylactic reaction, anaphylactic shock, refractory anaphylaxis and subheadings of diagnosis, classification, epidemiology, complications and pharmacology. The level of evidence supporting an intervention was evaluated based on the availability of randomized studies, expert opinion, case studies, reviews, practice parameters and other databases (including Cochrane).

STUDY SELECTION

Selected publications describing anaphylaxis, clinical trials, diagnosis, mechanisms, risk factors and management were retrieved (reviews, guidelines, clinical trials, case series) and their bibliographies were also reviewed to identify relevant publications.

DATA EXTRACTION

Data from the relevant publications were reviewed, summarized and the information synthesized.

DATA SYNTHESIS

This is a synthetic review and the data obtained from a literature review was utilized to describe current trends in the diagnosis and management of the patient with anaphylaxis with a special emphasis on newer evolving concepts of anaphylaxis endotypes and phenotypes, management of refractory anaphylaxis in the ICU setting and review of therapeutic options for the elderly patient, or the complicated patient with severe cardiorespiratory complications. Most of the recommendations come from practice parameters, case studies or expert opinions, with a dearth of randomized trials to support specific interventions.

CONCLUSION

Anaphylaxis is a rapidly progressive life-threatening disorder. The critical care physician needs to be familiar with the diagnosis, differential diagnosis, evaluation, and management of anaphylaxis. Skilled intervention in ICUs may be required for the patient with complicated, severe, or refractory anaphylaxis.

Perioperative approach of allergic patients

Perioperative allergic reactions are rare, yet important complications of anesthesia. Severe, generalized allergic reactions called anaphylaxis are estimated to have a mortality of 3.5-4.8%. Adequate recognition and handling of a severe perioperative anaphylactic reaction result in better outcomes, including less hypoxic-ischemic encephalopathy and death. The diagnosis of a perioperative allergic reaction can be difficult as the list of possible culprits of a perioperative allergic reaction is extensive. Making an informed guess on the causative agent and avoiding this agent in future anesthesia procedures is undesirable and unsafe. Therefore, to ensure future patient safety, a thorough investigation following a perioperative allergic reaction is mandatory. A collaborate approach by allergists and anesthesiologists is advised. In this article, we discuss the basic approach of the allergic patient and of patients with a suspected allergy to perioperatively administered medication.

Computed tomography-guided cyanoacrylate localization of small pulmonary nodules: feasibility and initial experience

OBJECTIVES

We report our initial technical experience with computed tomography (CT)-guided cyanoacrylate localization for resection of small pulmonary nodules (SPNs) and evaluate the feasibility of this technique.

METHODS

Between June 2016 and December 2017, the diagnostic results of 55 consecutive patients (69 SPNs) who underwent preoperative CT-guided cyanoacrylate localization and consequent video-assisted thoracoscopic surgery (VATS) resection were retrospectively evaluated. Localization-related outcomes and perioperative outcomes were assessed.

RESULTS

Preoperative CT-guided cyanoacrylate localization was successfully performed in all the cases. Simultaneous localization was achieved in 8 (14.5%) patients with 2 nodules and 3 (5.5%) patients with 3 nodules. The mean size of the nodules was 8.5 ± 3.2 mm (range 5-20 mm), and their mean depth from the nearest pleural surface was 10.9 ± 7.7 mm (range 2-36 mm). The overall mean localization procedural time was 13.7 ± 7.2 min (range 6-37 min). Two localization-related complications (intrapulmonary focal haemorrhage and pneumothorax) were observed in 7 (12.7%) and 12 (21.8%) patients, respectively. All patients with complications were asymptomatic and received conservative treatment only. All SPNs were resected under VATS without any conversion to minithoracotomy or thoracotomy.

CONCLUSIONS

CT-guided cyanoacrylate localization is a feasible procedure to localize SPNs. The advantages of this technique include flexibility between insertion and excision, the ability to be applied to the whole lung field, a high success rate, patient comfort after insertion and a fast learning curve. Further studies are warranted to confirm the efficacy of this technique.

Risk factors and treatment of refractory anaphylaxis - a review of case reports

INTRODUCTION

Patients experiencing anaphylaxis who do not recover after treatment with intramuscular adrenaline are regarded as suffering from refractory anaphylaxis. The incidence of refractory anaphylaxis is estimated to range between 3-5% of anaphylaxis cases. The risk factors for refractory anaphylaxis are unknown. Areas covered: In the present analysis, we aimed to evaluate the management and risk factors of refractory anaphylaxis to highlight possible clinical implications for updating current management algorithms. Expert commentary: According to international guidelines, adrenaline given through the intramuscular (i.m.) route is a rapid and safe treatment but may be insufficient. Therefore, defined standardized treatment protocols for such cases of refractory anaphylaxis are needed to optimize the treatment. Point-of-care diagnostics may enable doctors to identify patients experiencing severe, refractory anaphylaxis early in order to initiate intensified critical care treatment.

Are ACE Inhibitors and Beta-blockers Dangerous in Patients at Risk for Anaphylaxis?

The objective of this article is to review the available studies regarding angiotensin converting enzyme (ACE) inhibitors and beta-blockers and their effect on patients at risk for anaphylaxis. A literature search was conducted in PUBMED to identify peer-reviewed articles using the following keywords: anaphylaxis, ACE inhibitor, beta-blocker, food allergy, radiocontrast media, venom allergy, skin testing, and immunotherapy. Some studies show an increased risk of anaphylaxis in patients who are taking ACE inhibitors and beta-blockers, whereas others studies do not show an increased risk. For venom immunotherapy, there are more data supporting the concomitant use of beta-blockers and ACE inhibitors in the build-up and maintenance phases. Most of the medical literature is limited to case reports and retrospective data. Prospective controlled trials are needed on this important topic. For those patients at risk of anaphylaxis who lack cardiovascular disease, it is recommended to avoid beta-blockers and possibly ACE inhibitors. However, for those patients with cardiovascular disease, beta-blockers and ACE inhibitors have been shown to increase life expectancy. Consideration should be given for the concomitant use of these medications while patients are receiving venom immunotherapy.

Anaphylaxis

Anaphylaxis is an acute, systemic reaction mediated by immunoglobulin E hypersensitivity. Release of bioactive factors causes vasodilation and bronchiole constriction that can lead to hypotensive shock and asphyxiation. Differential diagnosis includes acute asthma, localized angioedema, syncope, and anxiety/panic attacks. Diagnostic tests lack specificity. Clinical diagnosis is based on demonstration of specific airway or cardiovascular compromise within proximity of allergen exposure. Treatment includes epinephrine, antihistamines, fluid resuscitation, and airway management. Prevention focuses on awareness/avoidance of triggers, implementation of personalized action plans, as well as immune modulation by desensitization in a closely controlled setting where available.

Methylene Blue Injection as an Alternative to Antegrade Nephrostography to Assess Urinary Obstruction After Percutaneous Nephrolithotomy

AIMS AND OBJECTIVES

Percutaneous nephrolithotomy (PCNL) remains an effective treatment for large stones. When nephrostomy tube (NT) is left post operation, antegrade urine flow is often confirmed with antegrade nephrostography (ANG) before tube removal. We compare methylene blue (MB) test combined with NT capping trial against ANG to assess antegrade urine flow after PCNL.

MATERIALS AND METHODS

One hundred one consecutive patients undergoing PCNL were prospectively enrolled between 7/2014 and 4/2015. An NT cap was placed the morning of postoperative day 1 (POD1). Failure was defined as need to uncap the NT for any reason. Two hours after capping, 7cc MB was injected into the NT. Positive MB test was defined as presence of blue per bladder Foley. ANG was then performed to assess antegrade urine flow. NTs were removed before discharge home when antegrade flow was documented. Primary outcomes included presence of antegrade flow on ANG and NT removal before discharge home. Receiver operating characteristic (ROC) and areas (Area under the ROC [AUC]), as well as Cohen's kappa coefficient (κ), were calculated comparing agreement of capping trial, MB, and ANG with NT removal.

RESULTS

One hundred one subjects were included in this analysis. 52.9% were left-sided surgeries and 60.4% utilized lower pole punctures. On ROC areas evaluating tests for agreement with NT removal before discharge, MB AUC 0.71 (95% CI 0.60-0.83), capping trial AUC 0.66 (95% CI 0.57-0.75), combed capping trial and MB AUC 0.72 (95% CI 0.61-0.84), and ANG AUC 0.78 (95% CI 0.68-0.88). In predicting NT removal, ANG performed better than capping trial alone (p = 0.042), but no differences were seen between MB and ANG (p = 0.229), combining the capping trial with MB test and ANG (p = 0.266) or combined testing and MB alone (p = 0.972).

CONCLUSIONS

Combining capping trial with MB injection is similarly accurate for predicting NT removal after PCNL compared to ANG. Capping trial and MB may be used in combination to obviate the need for ANG.