Clinical trial NCT01805063: Effect of Fire Suppression and Emergency Duties on Vascular Function
Official title: Effect of Fire Suppression and Emergency Duties on Vascular Function in Firefighters
Study type: OBSERVATIONAL
Overall status: COMPLETED
Conditions: Vascular Function
Atherothrombosis
Keywords: firefighters
myocardial infarction
endothelial function
thrombosis
fire suppression
non-fire emergency duty
sedentary shift
Lead sponsor: University of Edinburgh
Sponsor class: OTHER
First posted: 2013-03-05
Enrollment: 30
Sex: ALL
Minimum age (years): 18
Maximum age (years): 60
Standard ages: ADULT
Accepts healthy volunteers: yes
Observational model: CASE_CROSSOVER
Time perspective: PROSPECTIVE
Sampling method: PROBABILITY_SAMPLE
Study population: Subjects will be healthy, non-smoking, whole-time firefighters working within Lothian and Borders Fire and Rescue Service

Brief summary: Firefighters are at increased risk of death from heart attacks when compared to other emergencyy service professionals whose jobs involve similar components such as emergency call-outs and shift work. In the largest analysis of cause of death amongst on-duty firefighters, firefighter deaths were classified according to the duty performed during the onset of symptoms or immediately prior to any sudden death. The majority of deaths due to a cardiovascular cause (i.e. heart attack) occurred during fire suppression whilst this activity represented a relatively small amount of a firefighters professional time. There was also a risk of death associated with other duties such as emergency non-fire response and physical exertion.

The investigators hypothesize that participation in active fire-fighting duties impairs blood vessel function and increases blood clot formation when compared with non-fire-fighting activities. In this study, healthy career firefighters will be assessed after three periods of duty: fire-suppression, emergency response without fire suppression and following a sedentary shift. The investigators will take blood samples to measure platelet activity (platelets are the particles in blood that help blood clot) and will examine how blood clots outside of the body. The investigators will then perform studies placing small needles in the arm to assess blood vessel function following these duties. By undertaking this comprehensive assessment of blood, blood vessel and heart function the investigators hope to understand the mechanisms whereby the risk of a heart attack, fatal or otherwise, is posed throughout these distinct duties that firefighters undertake on a daily basis.


Eligibility criteria: Inclusion Criteria:

* Non-smoking healthy firefighters

Exclusion Criteria:

* Current smoker
* History of lung or ischaemic heart disease
* Malignant arrhythmia
* Systolic blood pressure \>190mmHg or \<100mmHg
* Renal or hepatic dysfunction
* Previous history of blood dyscrasia
* Unable to tolerate the supine position
* Blood donation within the last 3 months
* Recent respiratory tract infection within the past 4 weeks
* Routine medication including aspirin and NSAIDs

Primary outcomes:
measure: Forearm blood flow measured by venous occlusion plethysmography in response to infused vasodilators
timeFrame: up to 12 hours after exposure
Secondary outcomes:
measure: Ex-vivo thrombus formation using the Badimon chamber
timeFrame: up to 12 hours after exposure
measure: Plasma t-PA and PAI concentrations following infusion of bradykinin
timeFrame: During forearm study, up to 12 hours after exposure
Other outcomes:
Locations:
city: Edinburgh
country: United Kingdom
facility: Royal Infirmary of Edinburgh Clinical Research Facility
Study officials:
affiliation: University of Edinburgh
name: David E Newby, MD PhD
role: STUDY_CHAIR
affiliation: University of Edinburgh
name: Nicholas L Mills, MBChB PhD
role: STUDY_DIRECTOR
affiliation: University of Edinburgh
name: Amanda L Hunter, MBChB
role: PRINCIPAL_INVESTIGATOR
References: