Effects of Cardiovascular System and Arterial Blood Gas following Respinatory Pattern in One-Lung Ventilation and Pulmonary Edema

Lee, Chai Sung; Yang, Hong Seok; Choi, Byung Kwon

Abstract

Nowadays the importance of respiratory therapy is increasing with the development of modern medicine. Especially effective respiratory care in the field of anesthesia and intensive care unit has close relationship to the decrease of mortality or morbidity of the critically ill patients. Compared with spontaneous respiration, so various physiological changes related to these methods can occur. Because most modernized ventilations can choose the various respiratory patterns according to the patients' respiratory condition, it is ideal to select the respiratory mode which is least hazardous and most effective to the patients. To confirm the effects of respiratory therapy on the cardiovascular system and arterial blood gas in one-lung ventilation and in pulmonary edema, we made one-lung ventilation by deep right endobronchial intubation and ppulmonary edema was induced by oleid acid (0.05g/kg. IV) to 12 mongrel dogs. And we observed the cardiovascular changes and arterial blood gas analysis in the situation of applying the inspiratory pause(0.25sec. and 0.5sec) and positive end-expiratory pressure(5cm H2O and 10cm H2O). The results were as follows: 1) One-lung Ventilation. (i) Inspiratory pause-There were no changes of cardiovascular system and arterial blood gas in the inspiratory pause of 0.25 and 0.5 sec. (ii)PEEP-In 5cmH2O of PEEP there was no change of cardiovascular system, but there was decrease in PCO2(p<0.01) on arterial blood gas. In 10cmH2O of PEEP there was increase in heart rate(p<0.05) and decrease in cardiac output(p<0.05). There was decrease in PCO2(p<0.01), but there were no changes of pH and PO2 on arterial blood gas. 2) Pulmonary edema. (i) Inspiratory pause-There was increase in heart rate(p<0.01), but there was no change of arterial blood gas in the 0.25 and 0.5sec. inspiratory pause. (ii) PEEP- In 5cmH2O PEEP there was increase in heart rate(p<0.01), but there was no change of arterial blood gas in the 0.25 and 0.5 sec. inspiratory pause. In 10cmH2O PEEP there were decrease in sBP, dBP, MAP, increase in heart rate(p<0.05) and decrease in cardiac output(p<0.01). There were increase in pH(p<0.05) and PO2(p<0.01), decrease in PCO2. According to the above results in the condition of one-lung ventilation mechanical ventilation with inspiratory pause(0.25 or 0.5 sec) was not helpful to respiratory care. 5cmH2O PEEP could improve the pulmonary ventilation without ay changes of cardiovascular system, but 10cmH2O PEEP increased heart rate and decrease cardiac output. In the condition of pulmonary edema, mechanical ventilation with inspiratory pause(0.25 or 0.5 sec) could not improve the pulmonary ventilation with depression of cardiovascular system. PEEP (5 or 10 cmH2O) could improve the pulmonary condition in proportion to PEEP, but it also depressed the cardiovascular system. Therefore we concluded that mild degree PEEP (5cmH2O) may be helpful to the one-lung ventilation or pulmonary edema.