Change in the Phase III Slope of the Volumetric Capnography by Prone Positioning in Acute Respiratory Distress Syndrome

Assessment of the Effects of Prone Positioning Among ARDS Patients on Ventilation Homogenization by the Phase Iii Slope of the Volumetric Capnography

Status

Recruiting

Phases

Unknown

Study type

Observational

Source

ClinicalTrials.gov

Registry ID

NCT05535543

Enrollment

Registered

2022-09-10

Start date

2022-09-06

Completion date

2025-02-28

Last updated

2024-07-03

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

Conditions

Acute Respiratory Distress Syndrome, Respiratory Failure, Ventilation Perfusion Mismatch

Keywords

Acute Respiratory Distress Syndrome, Volumetric Capnography, phase iii slope, prone

Brief summary

This study evaluates the effects of prone positioning on homogenization of ventilation.

Detailed description

After initiation of mechanical ventilation and assessing the eligibility of the patient, informed consent will be taken from the closest kin. If eligible, following steps will be performed which are part of standard ARDS patient care. 1. Low-flow Pressure Volume curve and assessment of airway opening pressure 2. Calculation of recruitment to inflation ratio 3. Optimizing Positive End-Expiratory Pressure Afterwards, phase III slope of the patient will be recorded at four timepoints: Supine 1 (immediately before turning to prone position) Prone 1 (immediately after prone position) Prone 2 (at the end of the 16-24 hour prone cycle) Supine 2 (immediately after turning to supine position)

Interventions

PROCEDUREProne Positioning

Patients will be turned to prone position and they will be left in prone position for a duration of at least 16 hours to a maximum of 24 hours. This duration is recommended by the ARDS guidelines.

Study design

Observational model

COHORT

Time perspective

PROSPECTIVE

Eligibility

Sex/Gender

ALL

Age

18 Years to No maximum

Healthy volunteers

Inclusion criteria

* ARDS criteria met * intubated and mechanically ventilated as a result of respiratory failure * PaO2/FiO2 \<200

Exclusion criteria

* age older than 18 * Chronic pulmonary disease, pneumothoraces, intraabdominal hypertension (\> 12 mmHg), pregnancy, not expected to survive \>24 hours, hemodynamic instability

Design outcomes

Primary

Measure	Time frame	Description
Change from baseline in phase iii slope of the volumetric capnograph	16 to 24 hours (according to time spent in the prone position)	phase iii slope is associated with the ventilation homogeneity
correlation of the phase iii slope with the recruitment to inflation ratio	16 to 24 hours (according to time spent in the prone position)	recruitment to inflation ratio is a simple bedside tool that indicates a higher possible recruitable lung with higher applied Positive End-Expiratory Pressure

Secondary

Measure	Time frame	Description
correlation of the phase iii slope with the Partial pressure of the arterial oxygen/ Fraction of inspired O2 concentration (PaO2/FiO2) ratio	16 to 24 hours (according to time spent in the prone position)	PaO2/FiO2 is markedly reduced in ARDS patients as a consequence of aeration loss

Countries

Turkey (Türkiye)

Contacts

Primary ContactOlcay Dilken, MD

olcaydilken@gmail.com+905547378709

Outcome results

None listed

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