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Both intrinsic positive end expiratory pressure (PEEPi) and dynamic hyperinflation are considered as inspiratory loads which increase work of breathing in patients with COPD. The application of extrinsic positive end expiratory pressure (PEEPe) supplied by CPAP has been claimed to reduce inspiratory load based on change in esophageal pressure which could be significantly affected by change in lung volume and airflow. The investigator hypothesized that CPAP could increase respiratory load because it increases lung volume.
Objective: To assess the effect of CPAP on respiratory load and lung volume in stable COPD. Methods: Patients with COPD were recruited to breath under the atmosphere pressure and different levels of CPAP (4, 6, 8 and 10 cm H2O). Diaphragm EMG, esophageal pressure (Pes) and transdiaphragmatic pressure (Pdi) were recorded using balloon esophageal electrode catheter (Yinghui, Guangzhou, China). End inspiratory lung volume (EILV) was measured directly from a pneumotachograph combined with a three way valve under the different CPAP levels. Sensation of breathing difficulty was also assessed. In an additional study, the effect of airflow on pressure was investigated by a physical mode.
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| Label | Type | Description | Intervention Names |
|---|---|---|---|
| CPAP treatment | Experimental | CPAP treatment in COPD patients |
|
| Name | Type | Description | Arm Group Labels | Other Names |
|---|---|---|---|---|
| Continuous Positive Airway Pressure | Device | Patients with COPD were recruited to breath under the atmosphere pressure and different levels of CPAP (4, 6, 8 and 10 cm H2O). |
|
| Measure | Description | Time Frame |
|---|---|---|
| Diaphragm EMG | assessment of the electrical activity of the diaphragm (EMG-di) | Around 5 minutes signals under the atmosphere pressure and different levels of CPAP (4, 6, 8 and 10 cm H2O) were recorded. |
| Lung volume | measurement of end inspiratory lung volume (EILV) | 1-3 minutes after each CPAP level (0, 4, 6, 8 and 10 cm H2O) |
| Intrinsic positive end expiratory pressure (PEEPi) | PEEPi was calculated from the negative deflection in Pes from the onset of inspiratory effort to the point of zero flow during spontaneous breathing. | Around 5 minutes signals under the atmosphere pressure and different levels of CPAP (4, 6, 8 and 10 cm H2O) were recorded. |
| Inspiratory pressure | assessment of esophageal pressure and transdiaphragmatic pressure by caculating tidal variations in Pes (∆Pes) and Pdi (∆Pdi) relatived to initiation of effort. | Around 5 minutes signals under the atmosphere pressure and different levels of CPAP (4, 6, 8 and 10 cm H2O) were recorded. |
| Inspiratory work | the pressure-time product of the respiratory muscles (PTPes/min) and of the diaphragm (PTPdi/min) were calculated under the Pes and Pdi versus time curve and expressed per minute. | Around 5 minutes signals under the atmosphere pressure and different levels of CPAP (4, 6, 8 and 10 cm H2O) were recorded. |
| Sensation of breathing effort | Using questionnaire to assess the sensation of breathing effort. Sensation of breath effort of CPAP use was divided into three types corresponding to -1, 0, 1 score respectively, 0 refers to the same sensation as the feeling of breathing at the atmosphere without CPAP; 1 refers to the more difficult sensation to breath at the CPAP condition than at the atmosphere.; -1 refers to the easier sensation to breath at the CPAP condition than at the atmosphere. |
| Measure | Description | Time Frame |
|---|---|---|
| Respiratory rate (RR) | assessment of respiratory rate (RR) | Around 5 minutes signals under the atmosphere pressure and different levels of CPAP (4, 6, 8 and 10 cm H2O) were recorded. |
| Tidal volume (Vt) |
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Inclusion Criteria:
Exclusion Criteria:
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| Name | Affiliation | Role |
|---|---|---|
| Yuanming Luo, PHD | Guangzhou Medical University | Principal Investigator |
| Facility | Status | City | State | ZIP | Country | Contacts |
|---|---|---|---|---|---|---|
| Guangzhou Medical University | Guangzhou | Guangdong | China |
The data will be shared after the paper of this study publishing.
The data will be shared after the paper of this study publishing.
After the paper of this study publishing
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| ID | Term |
|---|---|
| D029424 | Pulmonary Disease, Chronic Obstructive |
| ID | Term |
|---|---|
| D008173 | Lung Diseases, Obstructive |
| D008171 | Lung Diseases |
| D012140 | Respiratory Tract Diseases |
| D002908 | Chronic Disease |
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| ID | Term |
|---|---|
| D045422 | Continuous Positive Airway Pressure |
| ID | Term |
|---|---|
| D011175 | Positive-Pressure Respiration |
| D012121 | Respiration, Artificial |
| D058109 | Airway Management |
| D013812 | Therapeutics |
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CPAP treatment
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| 5 minutes after each CPAP level (0, 4, 6, 8 and 10 cm H2O) |
assessment of tidal volume
| Around 5 minutes signals under the atmosphere pressure and different levels of CPAP (4, 6, 8 and 10 cm H2O) were recorded. |
| Minute ventilation (VE) | assessment of minute ventilation | Around 5 minutes signals under the atmosphere pressure and different levels of CPAP (4, 6, 8 and 10 cm H2O) were recorded. |
| Peak inspiratory flow rate | assessment of peak inspiratory flow rate | Around 5 minutes signals under the atmosphere pressure and different levels of CPAP (4, 6, 8 and 10 cm H2O) were recorded. |
| Expiratory muscle EMG | assessment of the electrical activity of the internal oblique muscle (EMG-obl) and the rectus muscle (EMG-rec) | Around 5 minutes signals under the atmosphere pressure and different levels of CPAP (4, 6, 8 and 10 cm H2O) were recorded. |
| Expiratory pressure | The change in Pga resulting from the contraction of the abdominal muscles during expiration was analyzed | Around 5 minutes signals under the atmosphere pressure and different levels of CPAP (4, 6, 8 and 10 cm H2O) were recorded. |
| D020969 |
| Disease Attributes |
| D010335 | Pathologic Processes |
| D013568 | Pathological Conditions, Signs and Symptoms |
| D012138 |
| Respiratory Therapy |