Vascular Function and Oxidative Stress in Emergency Medical Responders

NCT06985394 | Recruiting

• 1 other identifier: 2291409-1
• Study Type: interventional
• Target: 45
• Locations: 1 country
• Sites: 1

Brief Summary

The goal of this clinical trial is to characterize blood vessel function and oxidative stress (a harmful condition that damages cells and tissues) in emergency medical technicians (EMTs). The main questions it aims to answer are:

1. 1.Does an overnight shift work in emergency medical technicians reduce blood vessel function and increase oxidative stress?
2. 2.Can supplementing with antioxidants help reduce the negative effects of night shift work in emergency medical technicians?

Conditions

Cardiovascular Function in EMTs

Keywords

EMT; First Responder; Oxidative Stress; Paramedic; Emergency Medical Technician

Outcome Measures

Primary Outcomes (5)

• Flow Mediated Dilation (FMD)

  Flow-mediated dilation (FMD) is a frequently practiced non-invasive technique which images artery structure and blood flow before, during, and after a period of blood flow occlusion and subsequent increases in blood flow. This creates stress on the inner lining (i.e., endothelium) of the vasculature, inducing a cascade of events which results in relaxation of the smooth muscle surrounding the vessel. Reduced functioning of this mechanism is significantly associated with cardiovascular complications and disease. FMD will be used to assess the diameter and blood flow velocity of the artery located in the upper arm via ultrasonography.

  Visit 2 (1 day)

• Oxidative Stress

  Electron Paramagnetic Resonance (EPR) Spectroscopy measurements will be conducted using a specialized spectrometer (Bruker EMX Nano) which is designed to detect unpaired electrons in biological samples, a key indicator of oxidative damage. For the EPR procedure, frozen samples of blood plasma will be carefully collected from the participant following standard clinical protocols during their vascular function visits. Briefly, the spin trapping technique will be used where a stabilizing molecule (e.g., spin probe such as cyclic hydroxylamine \[CMH\]) reacts with the free radical (e.g., superoxide) to form a more stable radical species for analysis (nitroxide). The stable sample will then be placed in the EPR resonator, and the spectrometer will be calibrated using known standards to ensure accurate detection of nitroxide.

  Visit 3 (1 day)

• Passive Leg Movement (PLM)

  PLM is a newer, non-invasive method of assessing vascular function that is also mediated through the responsiveness of the endothelium. This assessment may provide additional insight on vascular function specific to the lower extremity. Briefly, participants will have one minute of blood flow velocity of the right femoral artery recorded (distal to inguinal crease, proximal to deep and superficial bifurcation) via Doppler ultrasound, while sitting with back upright, both legs supported, and knees fully extended (i.e., 180 degrees). Passive movement will then be initiated by a second team member who will continuously move the participant's right leg through 90 degrees of motion for two minutes. Participants will be urged to remain passive and to avoid any assistance with limb motion. Blood flow velocity of the right femoral artery will be continuously recorded during the entire 3 minute test to investigate changes in blood flow velocity during passive leg movement.

  Visit 2 (1 day)

• Flow Mediated Dilation (FMD)

  Flow-mediated dilation (FMD) is a frequently practiced non-invasive technique which images artery structure and blood flow before, during, and after a period of blood flow occlusion and subsequent increases in blood flow. This creates stress on the inner lining (i.e., endothelium) of the vasculature, inducing a cascade of events which results in relaxation of the smooth muscle surrounding the vessel. Reduced functioning of this mechanism is significantly associated with cardiovascular complications and disease. FMD will be used to assess the diameter and blood flow velocity of the artery located in the upper arm via ultrasonography.

  Visit 3 (1 day)

• Passive Leg Movement (PLM)

  PLM is a newer, non-invasive method of assessing vascular function that is also mediated through the responsiveness of the endothelium. This assessment may provide additional insight on vascular function specific to the lower extremity. Briefly, participants will have one minute of blood flow velocity of the right femoral artery recorded (distal to inguinal crease, proximal to deep and superficial bifurcation) via Doppler ultrasound, while sitting with back upright, both legs supported, and knees fully extended (i.e., 180 degrees). Passive movement will then be initiated by a second team member who will continuously move the participant's right leg through 90 degrees of motion for two minutes. Participants will be urged to remain passive and to avoid any assistance with limb motion. Blood flow velocity of the right femoral artery will be continuously recorded during the entire 3 minute test to investigate changes in blood flow velocity during passive leg movement.

  Visit 3 (1 day)

Study Arms (2)

Antioxidant Supplementation

EXPERIMENTAL

Participants will take two doses of antioxidant supplements in capsule form during their overnight shift: the first dose at 7:00 PM, and the second dose 1.5 hour before their morning vascular function visit (post-shift). Each dose will consist of the following concentrations of antioxidants: 600 mg of α-lipoic acid, 1,000 mg of vitamin C, and 600 IU of vitamin E.

Dietary Supplement: Antioxidant cocktail

Placebo Supplementation

PLACEBO COMPARATOR

Participants will take two doses of placebo supplements in capsule form during their overnight shift: the first dose at 7:00 PM, and the second dose 1.5 hour before their morning vascular function visit (post-shift). Each dose will consist of placebo pills made from microcrystalline cellulose, designed to match the antioxidants in taste, color, and appearance

Dietary Supplement: Placebo

Interventions

Antioxidant cocktail DIETARY_SUPPLEMENT

Participants will take two doses of antioxidant supplements in capsule form during their overnight shift: the first dose at 7:00 PM, and the second dose 1.5 hour before their morning vascular function visit (post-shift). Each dose will consist of the following concentrations of antioxidants: 600 mg of α-lipoic acid, 1,000 mg of vitamin C, and 600 IU of vitamin E.

Antioxidant Supplementation

Placebo DIETARY_SUPPLEMENT

Participants will take two doses of antioxidant supplements in capsule form during their overnight shift: the first dose at 7:00 PM, and the second dose 1.5 hour before their morning vascular function visit (post-shift). Each dose will consist of placebo pills made from microcrystalline cellulose, designed to match the antioxidants in taste, color, and appearance.

Placebo Supplementation

Eligibility Criteria

• Age: 20 Years - 40 Years
• Sex: all
• Healthy Volunteers: Yes
• Age Groups: Adult (18-64)

You may qualify if:

• Body mass index between 18.5 and \<35 kg/m²
• Seated resting systolic blood pressure \< 140 mmHg, and seated resting diastolic blood pressure \< 90 mmHg
• Participant must be an active first responder that works shift work schedules. e.g., emergency medical responders, basic life support emergency medical technicians (i.e., BLS EMT), advanced life support emergency medical technicians (A-EMT), and paramedics
• Participant must have been working shift work for at least 1 year
• Participant must work at least 4 night shifts per month

You may not qualify if:

• Participant is unwilling or unable to give consent
• Participant has been diagnosed with any chronic disease (a history of high blood pressure, heart disease, diabetes, cancer, kidney disease)
• Participant has been diagnosed with a sleep disorder (e.g., insomnia, restless leg syndrome, sleep apnea)
• Participant is currently taking melatonin or other sleep aids (e.g., Ambien, sedatives, etc.), or any supplements/medications known to alter sleep patterns. Participants using melatonin must undergo a minimum 72-hour washout period prior to study participation to ensure baseline sleep patterns are not affected\[15, 16\]
• Resting blood pressure \>140/90 mmHg
• Body mass index \<18.5 or \>35 kg/m2
• Currently pregnant or breast feeding (women only)
• Currently use tobacco or nicotine products (≥1 cigarette, cigar, e-cigarette, vape, or any other nicotine-containing product in the last month), including smokeless tobacco (e.g., chewing tobacco, snuff, dip, snus), nicotine lozenges or gum, heated tobacco products, and any illicit drugs

Sponsors & Collaborators

• University of Delaware: lead

Study Sites (1)

University of Delaware

Newark, Delaware, 19713, United States

RECRUITING

Central Study Contacts

Alexs Matias, MS

CONTACT

914-523-1953; amatias@udel.edu

Study Design

• Study Type: interventional
• Phase: not applicable
• Allocation: RANDOMIZED
• Masking: SINGLE
• Who Masked: PARTICIPANT
• Purpose: OTHER
• Intervention Model: CROSSOVER
• Sponsor Type: OTHER
• Responsible Party: SPONSOR

Study Record Dates

• First Submitted: February 25, 2025
• First Posted: May 22, 2025
• Study Start: May 14, 2025
• Primary Completion: September 1, 2025
• Study Completion: October 1, 2025
• Last Updated: May 22, 2025

Record last verified: 2025-02

Data Sharing

• IPD Sharing: Will not share

Locations

US (1)