Table 1 Summary of the different monitoring techniques

Pulse oximetry

Continuous

All patients receiving MV

Detection of hypoxemia

Ventilator pressures

Continuous

All patients receiving volume-controlled modes

Less reliable when patient is breathing actively

Ventilator traces

Continuous

All patients receiving MV

Clinicians need to learn how to read traces (no automatic detection)

Respiratory mechanics

Intermittent

Passive patients

ARDS, COPD

Less reliable when patient is awake

Pressure/volume curves

Intermittent

Passive patients

ARDS

Complex and need sedation and relatively homogeneous lungs

Work of breathing, pressure-time product

Intermittent

Respiratory distress, ventilator setting, weaning

Research

No automated measurement; needs esophageal pressure

Extravascular lung water

Intermittent

Pulmonary edema

Diagnosis of pulmonary edema

Complex and needs invasive devices

Lung volumes

Intermittent

ARDS

Could help to define risks of ventilation and assess recruitment

Need a passive patient

Electric impedance tomography

Continuous

ARDS

Could help to visualize regional ventilation

Needs a specific tool

Hemodynamic monitoring

Continuous or intermittent

Patients who have hemodynamic impairment and who are receiving MV

Helps to understand hypoxemia and its consequences

More or less invasive

Volumetric capnography

Continuous

ARDS

Complex analysis

Esophageal and transpulmonary pressure

Continuous or intermittent

ARDS

Could help to titrate ventilator pressures

Complex interpretation and difficult placement

Diaphragmatic electromyography

Continuous

Patients receiving assisted ventilation

Needs specific catheter, no absolute value