Related Experiment Video
Updated: Jun 20, 2026

Expired CO2 Measurement in Intubated or Spontaneously Breathing Patients from the Emergency Department
Published on: January 29, 2011
Hypercapnia test and weaning outcome from mechanical ventilation in COPD patients
J M Raurich1, G Rialp, J Ibáñez
1Intensive Care Unit, Son Dureta University Hospital, Palma de Mallorca, Illes Balears, Spain.
Abstract:
We evaluated the hypercapnia response test as a weaning outcome predictor from mechanical ventilation in patients with chronic obstructive pulmonary disease (COPD). We studied 44 COPD intubated patients considered ready for a weaning trial. The hypercapnia test was based on the modified method of re-inhalation of expired air Through the hypercapnic test we calculated the ratio of the change in minute volume (V(E)) to the change in PaCO2 (deltaV(E)/deltaPaCO2), the change in airway occlusion pressure at 0.1 second of inspiration (P0.1) to change in PaCO2 (deltaP0.1/deltaPACO2), the ratio of the change in P0.1 to baseline PaCO2 (deltaP0.1/PaCO2) and the ratio of the change in V(E) to baseline PaCO2 (deltaV(E)/PaCO2). Nineteen patients were successfully weaned and 25 patients failed. No differences in baseline clinical characteristics were found between the two groups. Weaning failure COPD patients had lower deltaP0.1/deltaPaCO2 (0.19 +/- 0.11 and 0.34 +/- 0.20 cm H2O/mmHg respectively, P = 0.006) and lower deltaV(E)/deltaPaCO2 (0.21 +/- 0.15 and 0.40 +/- 0.22 l/min/mmHg respectively, P = 0.002) than successfully weaned patients. The area under the receiver operating characteristic curve to discriminate weaning outcome was for the baseline PaCO2 0.81 (95% confidence interval: 0.66 to 0.91), hypercapnic PaCO2 0.76 (0.61 to 0.88), hypercapnic drive response 0.74 (0.59 to 0.86), hypercapnic ventilatory response 0.76 (0.60 to 0.87), deltaP0.1/PaCO2 0.76 (0.60 to 0.87) and for the deltaV(E)/PaCO2 0.81 (0.67 to 0.91). COPD patients with weaning failure have a significantly more blunted response to the hypercapnia response test than weaning success patients. This test could be useful to predict weaning failure patients if the combined values of the hypercapnic drive and hypercapnic ventilatory response were below the threshold values.
More Related Videos
Related Concept Videos
Assessment of Diffusion and Perfusion
The Role of Diffusion in Respiration
Diffusion is the process by which molecules move from an area of higher concentration to an area of lower concentration. In the respiratory system, this principle...
Acute Respiratory Failure-III
Mechanical Ventilation III: Noninvasive Ventilation
Noninvasive Positive-Pressure Ventilation (NIPPV)
Mechanical Ventilation I: Indication and Settings
Mechanical Ventilation II: Invasive Ventilation
Negative-Pressure Ventilators
Negative-pressure ventilators create a vacuum around the chest or body to draw air into the lungs, simulating breathing. This method does not require an...
Acute Respiratory Failure-I
Definition: It is defined by specific criteria based on blood gas measurements. Hypoxemia happens when the partial pressure of oxygen (PaO2) falls below 60 mmHg. At the same time,...

