Cardiac Contractility and Oxygen Consumption in Work-Related Heat Syncope

Details

• Personal Author:
  Klabunde R ; Wilson TE
• Description:
  People in occupations such as firefighting, as well as road repair, construction, mine, foundry, and bakery work, can experience extreme heat stress while performing work tasks in the upright position. Epidemiological data report incidence rates between 10-38 heat exhaustion cases per 100,000 in workers or soldiers in heat stress environments. Heat syncope is a distinct form of heat exhaustion and is related to postural pooling of blood, decreases in venous return, reductions in cardiac output, and cerebral ischemia. The causes and mechanisms of heat syncope are unclear; we believe there is an increase in left-ventricular contractility but not to an extent enough to prevent a fall in stroke volume during low-to-moderate reductions in preload that are associated with heat stressed humans in the upright position. The purpose of this pilot proposal is to identify the effect of heat stress on cardiac contractility and myocardial oxygen consumption while independently altering the variables that affect cardiac function in a manner consistent with the development of work-related heat syncope. An isolated rodent heart model will be used to test study hypotheses because human laboratory studies can only manipulate physiological variables to the point of pre-syncope, but field studies and heat exhaustion hospitalizations report more extreme physiological changes during heat syncope which can only safely be performed in the isolated heart model. Our central hypothesis for this project is that moderate heating increases left-ventricular contractility in the isolated heart model either directly (heating alone) or indirectly via interactions with a beta - adrenergic agonist (isoproterenol). These data will be informative as to the cardiac role in heat syncope and thereby lead to a combined mechanistic and applied translational research proposal to NIOSH dealing with work-related heat syncope etiology and countermeasure development. [Description provided by NIOSH]
• Subjects:
  Animals Cardiovascular Diseases Cardiovascular System Heat Stress Disorders Hot Temperature Occupational Health Safety
• Keywords:
  Cardiac Function Cardiovascular Disease Heat Exhaustion Heat Exposure Heat Stress Myocardial Disorders
• Publisher:
  University of Cincinnati
• Document Type:
  Text
• Funding:
  Grant
• Genre:
  Abstract or Summary
• Place as Subject:
  Ohio ; OSHA Region 5
• CIO:
  National Institute for Occupational Safety and Health (NIOSH)
• Topic:
  Workplace Safety & Health
• Location:
  North America
• Pages in Document:
  1
• NIOSHTIC Number:
  nn:20052621
• Citation:
  11th Annual Pilot Research Project Symposium, University of Cincinnati Education and Research Center, October 14 -15, 2010, Cincinnati, Ohio. Cincinnati, OH: University of Cincinnati, 2010 Oct; :1
• Federal Fiscal Year:
  2011
• Performing Organization:
  University of Cincinnati
• Peer Reviewed:
  True
• Start Date:
  20050701
• Source Full Name:
  11th Annual Pilot Research Project Symposium, University of Cincinnati Education and Research Center, October 14 -15, 2010, Cincinnati, Ohio
• End Date:
  20260630
• Collection(s):
  National Institute for Occupational Safety and Health
• Main Document Checksum:
  urn:sha-512:bfd816e9054f135c67c2142a9ff26ff1fcc07c82b22d74e0b438a81e193c8c23b992b0aa116b39de7cde00b2cd0ed30f506f3727c5d795fd6b3e12cd03166ea6
• Download URL:
  https://stacks.cdc.gov/view/cdc/212126/cdc_212126_DS1.pdf
• File Type:
  [PDF - 66.31 KB ]