Mechanical Ventilators

• Mechanical ventilation is classified based on the pattern of respiratory support that a patient receives while on a ventilator. These devices are designed to alter, transmit and direct energy to a patient's lungs in a way that simulates the work of breathing a person would normally perform on her own. However, this type of ventilation is not perfect, so the functional performance of these machines is not a cure all. When a person's lungs have failed for one reason or another, applying mechanical intervention for respiratory support should be as short term as possible.
  
  

Ventilator Modes

• Pressure support ventilation is a spontaneous breathing mode that can be used alone or in combination with other modes of ventilation, such as continuous positive airway pressure, or CPAP. A preset level of inspiratory pressure is delivered by the ventilator above the baseline pressure with each spontaneous breath taken by the patient. Volume-support ventilation combines pressure support ventilation with the safety of a volume guarantee during spontaneous breathing. Regardless of the mode, a preset respiratory rate can be set enabling the ventilator to breath for the patient when he cannot breathe on his own.
  
  

Measuring the Plateau Pressure

• A respiratory therapist most often manages the hour-by-hour monitoring of a patient's breathing when she is on a ventiloator. The therapist will record the patient's ventilator parameters as a way of more easily recognizing changes in her respiratory status. One of these parameters is the patient's plateau pressure. To know a patient's actual plateau pressure, the therapist will initiate an inspiratory hold by pressing the inspiratory hold button for one-half to one second. This process measures the patient's airway pressure from the peak of her breath until it drops down to a plateau.
  
  

Effects of High Pressure

• Plateau pressure in positive pressure ventilation is the pressure applied within the lung and small airways. Too high a pressure will cause trauma to the air sacs or alveoli in the lungs, so it is important to keep the plateau pressure within a specific range while on the ventilator. High plateau pressures require changes in ventilator modes, including a change in the level of oxygen, referred to as the FI02, until the pressures fall within a more acceptable level.