FCV vs VCV in Obstructive and Asthmatic Patients

The goal of this physiological pilot study with a randomized crossover design is to study the effect of Flow-controlled ventilation (FCV) on the minute volume compared to Volume-controlled ventilation (VCV) in intubated patients with an exacerbation of their asthma or COPD. Our hypothesis is that FCV will results in a lower minute volume compared to VCV in this patient category. Patients will be randomized between two ventilation sequences, namely 90 minutes of FCV followed by 90 minutes of VCV or vice versa.

Inclusion Criteria: * 18 years or older; * Provided written informed consent; * Undergoing controlled mechanical ventilation via an endotracheal tube; * Reason for intubation being exacerbation of asthma or COPD; * Intubated ≤72 hours Exclusion Criteria: * Severe sputum stasis or production requiring frequent bronchial suctioning (more than 5 times per nurse shift) * Untreated pneumothorax (i.e. no pleural drainage) * Hemodynamic instability defined as a mean arterial pressure below 60mmHg not responding to fluids and/or vasopressors or a noradrenalin dose \>0.5mcrg/kg/min * High (\>15 mmHg) or instable (an increase in sedation or osmotherapy is required) intracranial pressure * An inner tube diameter of 6mm or less * Anticipating withdrawal of life support and/or shift to palliation as the goal of care * Inability to perform adequate electrical impedance tomography (EIT) measurements with, e.g.: * Have a thorax circumference inappropriate for EIT-belt * Thoracic wounds, bandages or deformities preventing adequate fit of EIT-belt * Recent (\