Table 2.

Bedside Monitoring Techniques for Further Study

Modality	Acquisition	Potential Applications	Key Limitations
Lung ultrasound	Probe placed on chest transmits sound waves, records reflections back to probe	ARDS diagnosis Real-time monitoring of recruitment	Subjective image interpretation Cannot identify overdistension
Electrical impedance tomography	Electrodes on chest to monitor regional changes in electrical resistivity during ventilation	Real-time monitoring of recruitment to guide PEEP titration Breath-by-breath measure of regional overdistension	Precision & reproducibility of electrode placement Regionally limited (not global) lung image at level of belt position Diaphragm interference in caudal planes Limited availability
Esophageal pressure	Small-diameter esophageal balloon catheter inserted via oral or nasal route	Real-time monitoring of lung stress to guide tidal volume, PEEP titration Identify patient-ventilator dyssynchrony	Lack of consensus on whether absolute value reliably represents that of pleural pressure No estimate of regional differences in pleural pressure
Single-indicator transpulmonary thermodilution extravascular lung water	Temperature change, measured with femoral artery thermistor, following chilled saline bolus given via central venous catheter	ARDS severity and prognostication Guide fluid management	Cannot distinguish edema origin Typically requires femoral arterial catheter Limited availability