Continuous positive airway pressure (CPAP) and bilevel positive airway pressure (BiPAP) are two noninvasive ventilatory modes that are commonly used in the intensive care unit (ICU) as well as other settings. CPAP is commonly used on an outpatient basis to alleviate sleep apnea. Although less common, BiPAP may also be used for this purpose. While both of these modes may also be used for patients in the ICU who have this diagnosis, these modes are also commonly used to assist ICU patients who are having respiratory difficulty unrelated to sleep apnea. These situations include avoiding the need for invasive mechanical ventilation (e.g., endotracheal intubation) or to help bridge patients from invasive ventilation to supplemental oxygen only. This may be done in a variety of disease settings, including cardiogenic pulmonary edema; chronic obstructive pulmonary disease exacerbations postoperatively; adult respiratory distress syndrome; and others. Variable effectiveness has been described depending on the disease state.

Regardless of the disease state being treated or whether one is attempting to avoid intubation or bridging from invasive ventilation, close attention needs to be maintained so that the clinician is able to recognize when the patient is failing this noninvasive mode. While several studies point to these modes’ effectiveness in prevention of or weaning from invasive ventilation, it is clear that early recognition of the patient’s failing the noninvasive strategies is crucial to preventing morbidity. In general, a patient who is getting worse after an hour or so of noninvasive ventilation, as determined by his or her blood gas values and clinically assessed work of breathing, should be considered for intubation. If the patient is not improving but is not deteriorating, the CPAP or BiPAP may be continued, perhaps with adjustments to the pressure settings.