Intra-abdominal Pressures During the Spontaneous Breathing Trial

Measuring the Change of Intra-abdominal Pressures of the Intensive Care Unit Patients During the Spontaneous Breathing Trial

Increased intra-abdominal pressure (IAP) affects pulmonary dynamics. However, little is studied whether pulmonary dynamics affects IAP. We hypothesize that the change of IAP can also reflect the change of pulmonary dynamics. In this study, we choose patients who received spontaneous breathing trial to answer the hypothesis.

During the weaning process, we tapered down the respiratory support from mechanical ventilation and recruited respiratory muscles to work. Previous study showed that transdiaphragmatic pressure was increasing while pressure support was reducing. However, the transdiaphragmatic pressure required invasive procedure to measure and not used frequently in weaning. IAP reflects the pleural pressure. If the PEEP is not changed, change of IAP is largely due to change of transpulmonary pressure.

Study Aim:

1. To evaluate the patterns of change of IAP during SBT
2. To predict success of SBT by the change of IAP
3. To predict weaning outcome by the change of IAP

Inclusion Criteria:

• Adult patients with endotracheal intubation in the intensive care unit
• The clinical condition is considered to prepare for weaning assessment

Exclusion Criteria:

• tracheostomy
• severe heart failure, heart disease or arrhythmia
• upper airway obstruction related respiratory failure
• poor cooperation due to agitation
• no foley catheter in place or had been removed
• baseline IAP above 20 mmHg