The overall purpose to the study is to prospectively study how often patients with and without acute lung injury (ALI) have patient-ventilator asynchrony demonstrated as stacked breaths. The investigators seek to describe the quantity of stacked breaths by continuously recording flow, volume, and pressure waveforms routinely displayed on the vent. The investigators also seek to describe how primary ICU teams manage asynchrony documenting interventions of sedation or vent manipulation and what modality is most successful.

Inclusion Criteria:

age > 18 years intubated and mechanically ventilated diagnosed with acute lung injury (ALI) or requiring mechanical ventilation for reasons other than ALI

Exclusion Criteria:

neurological deficits (acute or chronic) that prevent effective diaphragm activity.

• Neuromuscular disease affecting the diaphragm
• Neuromuscular blockade

adult ICU patients receiving mechanical ventilation