The second law of thermodynamics says that the entropy of the universe (or any isolated system therein) is increasing; i.e., the energy of the universe is becoming more uniformly distributed. It is often noted that the second law indicates that nature tends to go from order to disorder, from complexity to simplicity.
Small-bore catheters and Heimlich valves have been successfully used in. the treatment of pneumothoraces in several studies.4,5 The thoracic vent. (see Figure 1) is a minimally invasive device for the treatment of. pneumothorax. It consists of a polyurethane catheter connected to a. plastic chamber containing a one-way valve.
Mechanical ventilation may be defined as the use of a mechanical device to provide. ventilator support for patients. There are 2 types of mechanical ventilation: positive and. negative pressure ventilation. Positive pressure ventilation delivers a positive pressure to. inflate the lungs. Expiration is passive.