Recent studies showed that the patient work of breathing may be unexpectedly high during mechanical ventilation. During assisted mechanical ventilation and synchronous intermittent mechanical ventilation particularly, attention must be paid to the patient work if the respiratory muscles are to be rested. Clinicians should observe chest wall movements to recognize inspiratory efforts and incoordination. Monitoring the profile of inspiratory airway pressure over time is also helpful, with irregular and only partially positive pressures indicating inspiratory effort by patients.