Abstract
BackgroundFood allergy is the most common cause of anaphylaxis. Changes in posture during acute reactions can trigger fatal outcomes, but the impact of allergic reactions on the cardiovascular system in nonfatal reactions remains poorly understood.ObjectiveOur aim was to systematically evaluate changes in cardiovascular function during acute allergic reactions to peanut.MethodsParticipants underwent double-blind placebo-controlled food challenge to peanut as part of a clinical trial. Changes in hemodynamic parameters (heart rate, stroke volume, blood pressure, and peripheral blood flow) and electrocardiogram findings during food challenges were assessed using noninvasive continuous monitoring.ResultsA total of 57 adults (median age 24 years [interquartile range = 20-29]), 53% of whom were female, participated; 22 (39%) had anaphylaxis. Acute reactions were associated with significant changes in stroke volume (mean decrease of 4.2% [95% CI = 0.8-7.6; P = .03]), heart rate (mean increase 11.6% [95% CI = 8.4-14.8; P < .0001]), and peripheral blood flow (mean increase 19.7% [95% CI = 10.8-28.6; P < .0001]), irrespective of reaction severity. These changes were reproduced at a subsequent repeat peanut challenge in 26 participants, and could be reversed with administration of intravenous fluids which resulted in faster resolution of abdominal symptoms.ConclusionsIn this first detailed human study of cardiovascular changes during food-induced allergic reactions, we found evidence for significant fluid redistribution, independent of reaction severity. This provides a sound rationale for optimizing venous return during significant allergic reactions to food. Finally, these data provide a new paradigm for understanding severity in anaphylaxis, in which poor outcomes may occur as a result of a failure in compensatory mechanisms.
Highlights
Food allergy is the most common cause of anaphylaxis
Acute reactions were associated with significant changes in stroke volume, heart rate, and peripheral blood flow, irrespective of reaction severity
With respect to HRV, we identified a number of significant changes at active challenge compared with the values at placebo challenge that were consistent with sympathetic activation: an increase in low-and high-frequency domains (P 5 .001 and P 5 .02 respectively [see Fig E6, B and C in this article’s Online Repository at www.jacionline.org]) and a decrease in approximate entropy and sample entropy parameters (P 5 .009 and P 5 .001, respectively [see Fig E6, D and E])
Summary
Food allergy is the most common cause of anaphylaxis. Changes in posture during acute reactions can trigger fatal outcomes, but the impact of allergic reactions on the cardiovascular system in nonfatal reactions remains poorly understood. Acute reactions were associated with significant changes in stroke volume (mean decrease of 4.2% [95% CI 5 0.8-7.6; P 5 .03]), heart rate (mean increase 11.6% [95% CI 5 8.4-14.8; P < .0001]), and peripheral blood flow (mean increase 19.7% [95% CI 5 10.8-28.6; P < .0001]), irrespective of reaction severity. These changes were reproduced at a subsequent repeat peanut challenge in 26 participants, and could be reversed with administration of intravenous fluids which resulted in faster resolution of abdominal symptoms. These data provide a new paradigm for understanding severity in anaphylaxis, in which poor outcomes may occur as a result of a failure in compensatory mechanisms. (J Allergy Clin Immunol 2021;147:633-42.)
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