Related Experiment Video
Updated: Jun 13, 2026

Expired CO2 Measurement in Intubated or Spontaneously Breathing Patients from the Emergency Department
Published on: January 29, 2011
Comparison between automatic tube compensation and continuous positive airway pressure during spontaneous breathing
Juan B Figueroa-Casas1, Ricardo Montoya, Alejandro Arzabala
1Division of Pulmonary and Critical Care Medicine, Texas Tech University Health Sciences Center, 4800 Alberta Avenue, El Paso, TX 79905, USA. juan.figueroa@ttuhsc.edu
Background:
Various methods to perform spontaneous breathing trials (SBTs) exist, but no one method has been shown to be superior. Automatic tube compensation (ATC) is a new and potentially advantageous ventilation mode to use during SBT. We compared ATC to continuous positive airway pressure (CPAP) during SBTs, to determine their efficacy in identifying patients ready to be liberated from mechanical ventilation.
Methods:
We randomized 118 adults in a general intensive care unit on mechanical ventilation for > or = 24 h who were about to undergo an SBT as part of an established respiratory-therapist-driven weaning protocol to undergo 30 min SBT with ATC or CPAP with no pressure support. We predefined the SBT-failure criteria. The primary outcome was duration of weaning (days from first SBT to extubation). Other outcomes included unsuccessful extubation within 48 h, first-SBT-pass rate, and total duration of mechanical ventilation.
Results:
We found a trend toward less failure of first SBT with ATC, compared to CPAP (3% vs 13% respectively, P = .09), but no difference in duration of weaning, rate of unsuccessful extubation, or duration of mechanical ventilation.
Conclusions:
When applied as part of a respiratory-therapist-driven weaning protocol in a general intensive-care population, SBTs with ATC were safe but did not hasten liberation from mechanical ventilation, when compared to CPAP.
Related Concept Videos
Mechanical Ventilation III: Noninvasive Ventilation
Noninvasive Positive-Pressure Ventilation (NIPPV)
Ventilatory Modes
There are three ventilatory modes: full support, partial support, and spontaneous. These are described below.
Full Support Modes
Full support modes include controlled mechanical ventilation, continuous mandatory...
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...
Mechanical Ventilation I: Indication and Settings
Cardiopulmonary Resuscitation II: ACLS Airway Management
Physiological Control of Respiration
Breathing, a seemingly passive process, is regulated by the respiratory center in the brainstem. This center coordinates the involuntary control of respirations, which means it occurs without conscious effort, ensuring a smooth and uninterrupted pattern.
Regulation of Ventilation
The body maintains ventilation by monitoring levels of carbon dioxide (CO2), oxygen (O2), and hydrogen ion concentration (pH) in the arterial blood. Among these factors, the level of CO2 plays a crucial...
