Pulmonary Gas Exchange in Shock in Humans

Abstract

SHOCK may be defined as a state of tissue underperfusion and cellular hypoxia. Usually the hypoxic state is secondary to circulatory inadequacy, but it is evident that other factors, secondary to shock itself, play an important role in tissue anaerobism. From our studies of patients in shock it became apparent that arterial blood oxygen tensions frequently were less than theoretically expected. Further, oxygen therapy did not improve this abnormality to the degree theoretically possible. These findings suggest that in shock, either shunting occurs through anatomic pulmonary arterial-venous fistulae or that ventilation perfusion abnormalities are present or that both conditions exist. The following studies were undertaken to define these and other phenomena. Methods and Materials Phase I. Concerns 57 patients in shock from various causes treated and studied at the University of Maryland Shock Trauma Unit (Table 1). The patients were grouped according to shock diagnosis, survival rates and whether or not there was pulmonary disease. Pulmonary disease was defined as evidence by history of respiratory symptoms (cough, sputum production, etc.) or

Integrated cardiorespiratory system model with short timescale control mechanisms

“…This behavior was reported previously in References 55, 54, 57, and 85. Regarding ventilatory variables predicted by the model, decreased as blood loss increased and this behavior has also been observed in experimental studies 61,62,87 (see Table 5) and is consistent with a recent study by Reference 86. Specifically to our model, this behavior occurs as a result of the formulation of the CVD.…”

Pulmonary Response to Major Injury

“…Second, in almost all cases, there is a definable cause for the pulmonary dysfunction. The causative factors of importance include (1) direct pulmo¬ nary injury, (2) sepsis, (3) aspiration of gastric contents, (4) head injury, and (5) fat embolization.…”

The lung in shock: A review

“…18 It is a frequent complication of fractures, especially fractures of long bones, pelViS or ribs, but it may occur after injury to other tissues containing fat. 4 Fat droplets are freed from the cells and enter the blood stream.…”