Cardiovascular changes during peanut-induced allergic reactions in human subjects

Abstract

Background: 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.

Objective: Our aim was to systematically evaluate changes in cardiovascular function during acute allergic reactions to peanut.

Methods: Participants 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.

Results: A 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.

Conclusions: In 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.

Keywords: Anaphylaxis; cardiac output; cardiovascular; food allergens; intravenous fluids; management; stroke volume; venous return.

Graphical abstract

Fig 1

Clinical symptoms observed at food challenge. OAS, Oral allergy symptom; CNS, change in level of consciousness.

Fig 2

Example traces from continuous noninvasive cardiovascular monitoring during active peanut challenge (A) and laser Doppler probe used to monitor cutaneous blood flow (B). OCR refers to the time point at which the stopping criteria were fulfilled. MAP, Mean arterial BP.

Fig 3

Changes in cardiovascular parameters at time of OCR during peanut-induced allergic reactions at active challenge compared to the placebo challenge: SV (A), cutaneous blood flow (measured at the nape of the neck) (B), systolic and diastolic BP (C and D), HR (E), and CO (F). Line and whiskers indicate medians and IQRs. ∗∗∗∗P < .0001; ∗∗∗P < .001; ∗P < .05; Wilcoxon signed rank test.

Fig 4

Time course for change in SV and HR before OCR. ∗P < .05; Wilcoxon signed rank test.

Fig 5

Changes in cardiovascular parameters at time of OCR from baseline, by reaction severity: SV(A), HR (B), CO(C), systolic and diastolic BP (D and E), cutaneous blood flow (F), low and high frequency domains in HRV (G and H), and sample entropy (SampEn) (I). Line and whiskers indicate medians and IQRs. Mann Whitney U test. ns, Not significant.

Fig 6

Impact of intravenous (IV) fluid administration following onset of OCR on the change in SV (A) and HR (B). Fourteen participants underwent a repeat challenge that resulted in similar symptom severity to their baseline challenge, and were treated with IV fluids (see text). SV and HR values are compared with the values at the equivalent time points for the initial DBPCFC, when no IV fluids were administered. Data are means ± SDs. ∗P < .05; t test. C, Time to resolution of gastrointestinal symptoms following OCR. Line and whiskers indicate medians and IQRs. ^#P < .05; Wilcoxon signed rank test.