The Effect of High-flow Nasal Cannula Flow Rates on Diaphragm Thickening Fraction in Adult Patients: A Prospective Physiologic Study

Status

Active, not recruiting

Phases

Unknown

Study type

Observational

Source

TCTR

Registry ID

TCTR20260711013

Enrollment

Registered

2026-07-11

Start date

2024-11-01

Completion date

Unknown

Last updated

2026-08-03

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

Conditions

Acute respiratory failure Pneumonia Sepsis Acute heart failure Post-extubation respiratory support Palliative care Respiratory muscles

Interventions

Adult inpatients in the medical wards aged 18 years or over receiving HFNC therapy for pneumonia, sepsis, acute heart failure, post-extubation respiratory support, or palliative supportive therapy. Pa

Basic Science

Adult HFNC Cohort

Eligibility

Sex/Gender

All

Age

18 Years to No maximum

Inclusion criteria

Inclusion criteria: 1. Admitted to an internal medicine ward. 2. Receiving high flow nasal cannula therapy. 3. High flow nasal cannula therapy initiated for pneumonia, sepsis, acute heart failure, post extubation respiratory support, or palliative respiratory support.

Exclusion criteria

Exclusion criteria: 1. ROX index of 9 or less. 2. Fraction of inspired oxygen above 0.40. 3. Respiratory rate above 24 breaths per minute. 4. Inability to tolerate changes in high flow nasal cannula flow rate. 5. Pregnancy. 6. Requirement for airborne isolation precautions. 7. Known diaphragmatic paralysis. 8. Hemodynamic instability, including uncontrolled atrial fibrillation with rapid ventricular response. 9. Presence of thoracic devices that interfere with diaphragmatic ultrasound assessment. 10. History of diaphragmatic surgery. 11. History of pneumothorax. 12. Presence of pulmonary air leak.

Design outcomes

Primary

Measure	Time frame
Diaphragmatic thickening fraction After a 15-minute stabilization period at each flow rate of 30, 40, 50, and 60 L/min Percentage calculated from end-inspiratory and end-expiratory diaphragm thickness using ultrasound	—

Secondary

Measure	Time frame
Physiological Parameters After a 15-minute stabilization period at each flow rate of 30, 40, 50, and 60 L/min Standard clinical monitoring of respiratory rate (RR), peripheral oxygen saturation (SpO2), heart rate, fraction of inspired oxygen (FiO2), and ROX index (pSpO2 divided by FiO2 ratio to RR)	—

Countries

Thailand

Contacts

Public ContactChichaya Nithisatienchai

Department of Internal Medicine, Faculty of Medicine, Thammasat University

Chichaya.nithi@gmail.com0821053476

Outcome results

None listed

Source: TCTR (via WHO ICTRP) · Data processed: Aug 10, 2026