Bioimpedance and Arterial Distension

Completed

• Conditions: Hypertension

• Registration Number: NCT01622842
• Lead Sponsor: Sense A/S

Brief Summary

The overall objectives were to investigate if characteristic dimensions for tissue and vessels determined from measured bioimpedance spectra would provide the same values as dimensions determined from MR images of the upper arm and verify that temporal variations of impedances could be converted to blood pressure.

Detailed Description

It is emphasized that measurements of pulse wave velocity was not a part of this trial, which implies that only uncalibrated blood pressures could be measured. The specific objectives were:

1. To determine conductivities and permittivities in the spectral region from 1 KHz to 1 MHz for persons with: (a) a normal distribution of fat and muscles, (b) exceptionally thick layers of subcutaneous fat, and (c) exceptionally thin layers of subcutaneous fat. Both sexes should be represented.

2. To verify that temporal variations synchronous with the heartbeat could be measured on all three groups.

Hypotheses:

A. That experimentally in vivo determined electrical parameters for tissues would differ considerably from theoretical values and from values measured in vitro experiments.

B. That the variations of the electrical parameters would exhibit little variation from person to person.

C. Those simple experimental relations can be established for the electrical parameters by including a simple vascularization model.

D. That it is possible to measure temporal variation of the impedance, which are synchronous with the heartbeat.

E. That the measured values would facilitate the calculation of the differential blood pressure with accuracies better than 10 mmHg.

Study Timeline

• Study Start: 2011-09
• Primary Completion: 2011-09
• Study Completion: 2011-12
• Status Verified: 2012-06
• Study First Submitted: 2012-06-08
• Study First Submitted QC: 2012-06-14
• Study First Posted: 2012-06-19
• Last Update Submitted: 2012-06-21
• Last Update Posted: 2012-06-22

Recruitment & Eligibility

• Status: COMPLETED
• Sex: All
• Target Recruitment: 16

Inclusion Criteria

• Age 18 - 80 years
• Mental ability to understand information to test subjects

Exclusion Criteria

• Serious illness
• Allergic reactions to ECG or EMG electrodes
• Mentally unstable or unable to perceive instructions
• Metal implants
• Claustrophobia
• Disqualified for MR scanning
• Pregnant

Study & Design

• Study Type: OBSERVATIONAL
• Study Design: Not specified

Primary Outcome Measures

Name	Time	Method
Conductivities and permittivities in the spectral region from 1 KHz to 1 MHz.	1 hour	Measured on persons with: (a) a normal distribution of fat and muscles, (b) exceptionally thick layers of subcutaneous fat, and (c) exceptionally thin layers of subcutaneous fat. Both sexes should be represented. Muscles and vessels followed expectations based on litterature values for electrical properties. Subcutaneous fat had a higher conductivity and permittivity than predicted from literature values in all cases.

Secondary Outcome Measures

Name	Time	Method
Temporal variations synchronous with the heartbeat	1 hour	The temporal variations of impedances measured on persons with: (a) a normal distribution of fat and muscles, (b) exceptionally thick layers of subcutaneous fat, and (c) exceptionally thin layers of subcutaneous fat. Both sexes should be represented. Temporal variations could be measured on all three groups.

Trial Locations

Locations (1)

Rigshopsitalet (Copenhagen Univ. Hospital); 🇩🇰 Copenhagen, Denmark