Plethysmography Curve Variability Depending on the Breath Cycle

Status

Completed

Phases

Study type

Interventional

Source

ClinicalTrials.gov

Registry ID

NCT05302219

Enrollment

Registered

2022-03-31

Start date

2022-03-10

Completion date

2022-06-30

Last updated

2025-03-25

For informational purposes only — not medical advice. Sourced from public registries and may not reflect the latest updates. Terms

Conditions

Apnea, Circulatory; Change, Respiration

Keywords

pulse oximetry, photoplethysmography curve, breath cycle, apnea

Brief summary

The aim of the study is to analyze the variability of plethysmography curve depending on the breath cycle (respiratory rate and tidal volume).

Detailed description

The plethysmography curve measured by finger sensors using pulse oximetry shows the changes in blood volume at the measured site. The presence of respiratory information within the pulse oximeter signal is a well-documented phenomenon. However, previous studies have mainly focused on extracting the respiratory rate from the plethysmography curve. The aim of this study is to analyze the variability of plethysmography curve as a function of both respiratory rate and tidal volume. Furthermore, the aim is to analyze the possibilities of apneic pause detection from the plethysmography curve.

Interventions

OTHERRespiratory rate

The participant alternates respiratory rates of 30, 15 and 7.5 breaths/min. Breathe each frequency for 2 minutes with a one-minute break.

OTHERTidal volume

The participant alternates tidal volumes of approx. 2, 1 and 0.5 litres. Breathe each tidal volume for 2 minutes with a one-minute break.

OTHERApnea

The participant simulates three apneic pauses lasting 1 minute with a two-minute break.

Study design

Allocation

Intervention model

SINGLE_GROUP

Primary purpose

OTHER

Masking

NONE

Intervention model description

All participants go through all assigned interventions in one study arm.

Eligibility

Sex/Gender

ALL

Age

18 Years to 30 Years

Healthy volunteers

Yes

Inclusion criteria

* healthy volunteers/students from the Czech Technical University in Prague

Exclusion criteria

* any acute illness * pregnancy * severe cardiovascular conditions * severe asthma or other severe respiratory conditions * diabetes * hypotension or hypertension

Design outcomes

Primary

Measure	Time frame	Description
Variability of plethysmography curve depending on the respiratory rate	1 hour	The effect of different respiratory rates (including apnea-zero respiratory rate) on the shape of the plethysmography curve will be evaluated.
Variability of plethysmography curve depending on the tidal volume	1 hour	The effect of different tidal volumes (including apnea-zero tidal volume) on the shape of the plethysmography curve will be evaluated.

Countries

Czechia

Outcome results

None listed

Source: ClinicalTrials.gov · Data processed: Feb 4, 2026