FCV vs VCV in Obstructive and Asthmatic Patients

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 (\<7 days) pulmonary surgery including pneumonectomy, lobectomy or lung transplantation * ICD device present (potential interference with proper functioning of the EIT device and ICD device) * Excessive subcutaneous emphysema * Contra-indications for nasogastric tube or inability to perform adequate transpulmonary pressure measurements with, e.g.: * Recent esophageal surgery * Prior esophagectomy * Known presence of esophageal varices * Severe bleeding disorders