Current Ventilator Strategies for ARDS
Acute Respiratory Distress Syndrome is a complex pathology involving the lung??™s loss of compliance due to trauma of some sort. Over the years strategies have changed and updated along with medical technology. Since the advent of mechanical ventilation, therapists have learned to improve patient??™s oxygenation to reverse the deadly syndrome.
One current strategy to mechanically ventilate ARDS patients is to program the ventilator for low tidal volumes and high respiratory rate. The therapist focuses on keeping a tidal volume of about 5 to 7 mL / kg and set the respiratory rate at 20 to 25 breaths/min. The goal is to establish a plateau pressure less than 30 cm of water positive expiratory end pressure with continuous positive air pressure to reduce telecasts.
Since the tidal volume is low, the patient??™s Paco2 is allowed to increase . This permissive hypercapnia is considered a tradeoff to increase compliance. The patient??™s hypercapnia should not be permitted to the point of going into severe acidosis, but the high respiratory rate should compensate for the increased Paco2.
The end-goal of the therapist is to decrease high transpulmonary pressures, reduce lung distention, and decrease barotraumas. Any patient struggling with lung compliance must avoid the condition which increase the chances of low lung compliance. Large chest expansion increases the chance of distress, so the therapist focuses on lowering that pressure identified with transpulmonary pressure. Second, the lungs should not be overly distended keeping down pressure and barotraumas.
As a further step, antibiotics and diuretic agents are prescribed to reduce secondary infection and stop interstitial edema.