Oxygen Consumption (VO2), Effort, and Weaning in the Mechanically Ventilated Patient in the Intensive Care Unit (ICU)

In patients who are mechanically ventilated for more than 72 hours weaning failure is a common issue. The Spontaneous breathing trial (SBT) is often done to assess if the patient can be extubated with a high chance of success. However, re-intubation rates are between 15 - 20 % after a successful SBT. The rapid shallow breathing index (RSBI) is an important parameter used in an SBT. Because the high incidence of extubation failure (re-intubation within 48 hours) a search for a better parameter than the RSBI is warranted. Using the measured end-tidal oxygen (etO2) of mechanically ventilated patients it is possible to calculate the VO2, which is a measure of patient effort. The VO2 is a parameter with the potential to predict weaning success or failure, together with other parameters of patient effort like the work of breathing (WOB), pressure time product (PTP) and esophageal pressure swings, reflecting muscle strength of the diaphragm. Therefore, the investigators want to investigate if these parameters are associated with an SBT success or failure.