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Microparticles in Scuba Divers With Decompression Sickness

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ClinicalTrials.gov Identifier: NCT01587209
Recruitment Status : Completed
First Posted : April 30, 2012
Last Update Posted : August 22, 2016
Information provided by (Responsible Party):

Study Description
Brief Summary:
The investigators hypothesize that membrane microparticles (MPs) are liberated into the blood stream in response to decompression stress and that certain MPs characteristics initiate inflammatory responses that contribute to the clinical syndrome the investigators call decompression sickness. The research goal is to evaluate the number, type and time-course for elevations in MPs in sport SCUBA divers who present for treatment of decompression sickness. Blood samples are to be taken from consenting patients before and after they undergo treatment for decompression sickness and at a follow-up clinic visit from 1 to 3 weeks later (three samples total).

Condition or disease
Decompression Sickness Dysbarism

Detailed Description:
Microparticles (MPs) are small membrane bound vesicles shed from the surface of a variety of cells by what appear to be well regulated processes. They are elevated in many physiological and disease states and in some instances have been associated with organ injury. Shear stress - as can be caused by intravascular bubbles - is one of the stimuli known to cause cells to release microparticles. Most sport SCUBA dives have been shown to generate intravascular bubbles - even safe dives well within limits established by the US Navy and sports authorities. The investigators have reported elevations in several sub-types of MPs in a group of individuals undergoing a well monitored series of open-water SCUBA dives. There is no information of the occurrence of MPs in injured divers. The investigators have published results using a murine model which demonstrated that mice subjected to varying decompression stresses exhibit progressive elevations in circulating MPs derived from leukocytes, erythrocytes, platelets and endothelial cells. Using novel interventions the investigators demonstrated that MPs cause intravascular neutrophil activation and inflammatory perivascular injuries. Therefore, there is pathophysiological information to suggest that one or more element of MPs (number and/or pro-inflammatory subtype) may be proximal elements that precipitate the clinical syndrome the investigators call decompression sickness.

Study Design

Study Type : Observational
Actual Enrollment : 1 participants
Observational Model: Case-Only
Time Perspective: Prospective
Official Title: Phase 1 Study Investigating Alterations of Circulating Microparticles in Scuba Divers With Decompression Sickness
Study Start Date : August 2011
Primary Completion Date : September 2014
Study Completion Date : September 2014
Groups and Cohorts

Divers with decompression sickness
The sole group under study is SCUBA divers who have sustained decompression sickness

Outcome Measures

Primary Outcome Measures :
  1. Microparticle elevations in injured divers [ Time Frame: four years ]
    We will quantify microparticles in plasma by standard flow cytometry techniques.

Secondary Outcome Measures :
  1. Microparticle sub-types in injured divers [ Time Frame: four years ]
    We will evaluate sub-types of microparticles to determine their cells of origin.

  2. Neutrophil activation in injured divers [ Time Frame: four years ]
    We will evaluate presence of neutrophil activation in injured divers.

Eligibility Criteria

Information from the National Library of Medicine

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Ages Eligible for Study:   18 Years and older   (Adult, Senior)
Sexes Eligible for Study:   All
Accepts Healthy Volunteers:   No
Sampling Method:   Non-Probability Sample
Study Population
SCUBA divers over age 21 that present for evaluation of suspected decompression sickness

Inclusion Criteria:

  • Patients who are given the diagnosis of decompression sickness will be offered entry into this study

Exclusion Criteria:

  • Inability to provide informed consent
Contacts and Locations

Information from the National Library of Medicine

To learn more about this study, you or your doctor may contact the study research staff using the contact information provided by the sponsor.

Please refer to this study by its ClinicalTrials.gov identifier (NCT number): NCT01587209

United States, Pennsylvania
University of Pennsylvania
Philadelphia, Pennsylvania, United States, 19104-6068
Sponsors and Collaborators
University of Pennsylvania
Office of Naval Research (ONR)
University of Maryland
Principal Investigator: Stephen R Thom, MD,PhD University of Pennsylvania