Table 3.
Pathophysiologic factors associated with weaning failure.
Neurological factors | Decreased respiratory center output, electrolyte disorders, sedation, and sleep apnea |
Phrenic nerve dysfunction | |
Muscle pump dysfunction | Hyperinflation, acidosis-electrolyte disorders, malnutrition, and critical ilness neuromyopathy Diaphragmatic dysfunction |
Increased ventilation demands | Increased CO2 production Dead-space ventilation |
Increased mechanical load | Increased airway resistance (tube, central, or smaller airways) |
Reduced lung compliance (alveolar filling, atelectasis, and fibrosis) | |
Increased chest wall elastance | |
Reduced lung elastic recoil (COPD) | |
Intrinsic PEEP | |
Cardiovascular | Increased metabolic demand Increased venous return Increased left ventricular afterload |
Endocrine dysfunction | Hypothyroidism and myxedema |
Psychological factors | Anxiety, delirium, and sleep deprivation |