NB. Changes in bronchial and pulmonary arterial blood flow with progressive tension pneumothorax

Charan. Changes in bronchial and pulmonary arterial blood flowwith progressive tension pneumothorax.J. Appl. Physiol. 81(4): 1664–1669, 1996.—We studied the effects of unilateral tension pneumothorax and its release on bronchial and pulmonary arterial blood flow and gas exchange in 10 adult anesthetized and mechanically ventilated sheep with chroni-cally implanted ultrasonic flow probes. Right pleural pres-sure (Ppl) was increased in two steps from 25 to 10 and 25 cmH2O and then decreased to 10 and25 cmH2O. Each level of Ppl was maintained for 5 min. Bronchial blood flow, right and left pulmonary arterial flows, cardiac output (Q̇T), hemody-namic measurements, and arterial blood gases were obtained at the end of each period. Pneumothorax resulted in a 66% decrease in Q̇T, bronchial blood flow decreased by 84%, and right pulmonary arterial flow decreased by 80 % at Ppl of 2