Comparative Effects of Propofol vs Enflurane on Cardiopulmonary Change during Transthoracic Endoscopic Sympathectomy / 대한마취과학회지

BACKGROUND: Respiratory function and pulmonary gas exchange are affected in thoracoscopic procedures where a pneumothorax is introduced using CO2. Carbon dioxide absorption into the blood during thoracoscopic surgery using intrathoracic carbon dioxide insufflation may lead to respiratory acidosis, increased ventilation requirements, and possible serious cardiovascular compromise. In the present study, the effects of propofol on pulmonary gas exchange were compared with those of enflurane in patients undergoing transthoracic endoscopic sympathectomy (TES) during standard tube ventilation with CO2 insufflation to the surgical side in a prospective randomised manner. METHODS: Sixteen patients with ASA physical status I were divided randomly into enflurane or propofol groups. After induction of anesthesia, patients were ventilated in the same mode in each group. Heart rate and mean arterial pressure were checked and blood gas analyses were performed at 3 time points: 10 min after induction of anesthesia (stage 1), 10 min after CO2 insufflation to the surgical side (stage 2), 10 min after CO2 desufflation from the surgical side (stage 3) under two lung ventilation during TES. RESULTS: Arterial oxygen tension (PaO2) did not differ significantly between enflurane and propofol groups and showed no difference among each stage. PaCO2 and end-tidal CO2 (PetCO2) increased significantly at stage 2 compared to stage 1 and then decreased significantly at stage 3 compared to stage 2 (P < 0.05). There were no significant changes in the mean arterial pressure throughout the procedure with CO2 insufflation in both groups, whereas heart rate was significantly lower in the propofol group than in the enflurane group (P < 0.05) at each stage. CONCLUSIONS: This study demonstrates that pulmonary gas exchange in patients with TES using standard tube ventilation with CO2 insufflation to the surgical side is not affected by choice of anesthesia.

Comparison of Gas Exchange Indices after Open Heart Surgery / 대한마취과학회지

BACKGROUND: The objectives of the study were to determine how gas exchanges indices including alveolar-arterial oxygen tension difference(A-aDO2), PaO2/PAO2, PaO2/FIO2 and pulmonary shunt ratio (QS/QT) were changed after open heart surgery according to the change of inspired fraction of oxygen(FIO2) and to identify the reliable parameters for postoperative respiratory care in the intensive care unit. METHODS: Blood gases were measured from radial and pulmonary arterial blood for arterial and mixed venous blood in 15 patients, with a mean age of 45.1 yr, after open heart surgery, in mechanically ventilated states with 1.0, 0.6 and 0.4 of FIO2 with normocarbia maintained (PaCO2 30~40 mmHg). Above mentioned gas exchange indices were calculated and compared. RESULTS: After decreasing the FIO2 from 1.0 to 0.6 and 0.4 in order, the major changes were significant decrease in pulmonary shunt ratio : 24+/-3%, 17+/-3% and 11+/-3% at FIO2 1.0, 0.6 and 0.4, respectively and A-aDO2 : 347+/-34 mmHg, 184+/-16 mmHg and 94+/-11 mmHg at FIO2 1.0, 0.6 and 0.4 respectively, while PaO2/PAO2 showed the only significant increase at FIO2 0.4 compared with those at FIO2 1.0 and PaO2/FIO2 was unchanged. CONCLUSIONS: In cases of open heart surgical patient with cardiovascular stability, pulmonary shunt ratio and A-aDO2 appear to be more sensitive on gas exchange, but the oxygen tension indices such as PaO2/PAO2 as well as PaO2/FIO2 might be suggested as possible alternatives for the shunt measurement.