Regional Ventilation During High Flow Nasal Cannula and Conventional Nasal Cannula in Patients With Hypoxia

Not Applicable

Completed

• Conditions: Oxygen Therapy; High Flow Nasal Cannula; Ventilation; Hypoxia
• Interventions: Device: Conventional nasal cannula followed by HFNC; Device: HFNC followed by conventional nasal cannula

• Registration Number: NCT02943863
• Lead Sponsor: Asan Medical Center

Brief Summary

High-flow nasal cannula (HFNC) that uses heated and humidified oxygen was recently introduced for bedside care. It has been shown to be associated with reduced risks of tracheal intubation rates and mortality in adult hypoxic patients.

The mechanisms of the effects of HFNC are thought to be related to the favorable effects of the heated and humidified gas, the high-flow rate used to minimize the entrainment of room air, and an increase in the ventilation efficiency, including the elimination of nasopharyngeal dead space, positive end-expiratory pressure (PEEP) effects, and improvements in paradoxical abdominal movement. Regarding the effects on lung volume, global ventilation in the lungs increases during HFNC, which is thought to attribute to PEEP effects. However, how regional ventilation is affected during HFNC in comparison with conventional NC remains unknown.

Because PEEP in mechanically ventilated patients improves the regional homogeneity of ventilation, investigators postulated that HFNC via PEEP effects would result in more homogeneous regional distributions in the ventilation changes. Investigators therefore assessed global and regional ventilation in patients with hypoxia receiving care via HFNC using electric impedance tomography and compared these results with conventional nasal cannula.

Detailed Description

Not available

Study Timeline

• Study Start: 2014-09
• Primary Completion: 2015-02
• Study Completion: 2015-02
• Status Verified: 2016-10
• Study First Submitted: 2016-10-21
• Study First Submitted QC: 2016-10-23
• Last Update Submitted: 2016-10-23
• Study First Posted: 2016-10-25
• Last Update Posted: 2016-10-25

Recruitment & Eligibility

• Status: COMPLETED
• Sex: All
• Target Recruitment: 24

Inclusion Criteria

• Age >20 years
• Subjective dyspnea in room air
• SaO2< 90% in room air
• Oxygen requirement for nasal cannula < 6 L/m

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Exclusion Criteria

• Unstable vital signs

  • SBP <90 mmHg
  • DBP < 60 mmHg
  • Heart rate > 120 bpm
  • Respiratory rate > 30 bpm
  • Persistent dyspnea under oxygen therapy using NC

• Severe hypoxia

  • PaO2/FiO2< 200 mmHg

• Unable to cooperate

  • Delirium
  • Reduced cognitive function

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Study & Design

• Study Type: INTERVENTIONAL
• Study Design: CROSSOVER

Arm && Interventions

Group	Intervention	Description
LFS first	Conventional nasal cannula followed by HFNC	Patients in "LFS first" receive oxygen therapy using conventional nasal cannula in ahead of HFNC therapy. After 20 minutes of conventional nasal cannula oxygen therapy, patients receive HFNC oxygen therapy.
HFNC first	HFNC followed by conventional nasal cannula	Patients in "HFNC first" receive oxygen therapy using HFNC in ahead of conventional nasal cannula oxygen therapy. After 20 minutes of HFNC therapy, patients receive conventional nasal cannula oxygen therapy.

Primary Outcome Measures

Name	Time	Method
Tidal variation	Twenty minutes after each oxygen therapy. (At the end of each oxygen therapy)	Tidal variation using electric impedance tomography

Secondary Outcome Measures

Name	Time	Method
Respiration Rate	Twenty minutes after each oxygen therapy. (At the end of each oxygen therapy)
Subjective comfort	Twenty minutes after each oxygen therapy. (At the end of each oxygen therapy)	Subjective comfort using questionnaire
Oxygen saturation	Twenty minutes after each oxygen therapy. (At the end of each oxygen therapy)	Oxygen saturation at using pulse oxymeter