Respiratory function in mechanically ventilated patients (VP) is adversely affected by starvation and hypermetabolic stress. These patients are more successfully managed and extubated if proper nutritional support is provided. The features of metabolism and respiratory function in VP require moderation in glucose, fat, and protein administration. In delivering energy to VP, attention must be given to nearby tracheostomy sites complicating the parenteral route and airway-cuff problems that may inhibit effective enteral feeding.