Optimizing Mechanical Ventilation by Bedside Lung Monitoring Systems in Critically ill Patients

Abstract

Since the original description of the acute respiratory distress syndrome (ARDS) in the Lancet by Ashbaugh et al. in 1967, numerous studies have aimed to improve mechanical ventilation in order to prevent the associated ventilatorinduced lung injury (VILI). In 2000, the landmark study of the ARDSnet group demonstrated that the application of tidal volumes of 6 ml/kg body weight resulted in a reduced mortality rate. This is now widely implemented as ‘protective ventilation’, not only in ARDS patients, but also in mechanically ventilated patients on both the operation room and the intensive care unit (ICU). Descriptions of ‘assisted’ ventilation can be found over the centuries. The first reports of negative and positive pressure mechanical ventilation appeared in the early 1800s. In those days, the negative pressure ventilator was the modality most frequently used. This was first described in 1838 by John Dalziel, a Scottish physician. The patient was placed in sitting position in an airtight box, with only the head left outside. Subsequently, air was manually pumped in and out of the box to change the pressure within the box and in the patient’s thoracic cage, thereby expanding the lungs while the patient was able to breathe room air. In 1928, the first iron lung was introduced by Drinker and was further improved in the following decades, and then widely used during the polio epidemics from the 1930s to 1960s. During this period, entire wards of patients were ventilated with these devices. Even prototypes of entire negative pressure operation rooms were designed. However, the equipment was very large, patients were difficult to reach, and effective ventilation with high airway pressure and application of positive endexpiratory airway pressure (PEEP) was not possible.