The Study of the Effect of Maternal FiO2 on the Umbilical Blood Gas Analysis and Maternal Awareness in Cesarean Section under General Anesthesia / 대한마취과학회지

General anesthesia for cesarean section usually includes 50% oxygen and nitrous oxide, supplemented by a low concentration of a volatile agent. This is based upon data demonstrating that an increase in maternal FiO2(inspired oxygen concentration) to more than 0.6 did not improve fetal oxygenation, But the use of 100% oxygen supplemented only by volatile anesthetics probably is safe in the case of emergency operation or fetal distress and advantageous in prevention of maternal awareness during cesarean section. The present study was designed to compare the effect of increasing FiO2 upon fetal oxygenation. It was also proposed to determine awareness, by questioning patients as well about dreams or other manifestations of inadequate depth of anesthesia. 30 patients undergoing cesarean section under general anesthesia were selected and they were allocated randomly into three groups according to FiO2 as follows; Group 1(n=10): FiO2 0.33 with 0.75 vo1% isoflurane, Group 2(n=10): FiO2 0.66 with 0.75vo1% isoflurane, Group 3(n= 10): FiO2 1.0 with 0.75 vo1% isoflurane. For the induction of anesthesia, thiopental 4 mg/kg was administered, followed by succinylcholine 1.5 mg/kg. After intubation, the lung was ventilated with different FiO2 and maternal arterial blood was sampled just before delivery and umbilical arterial and venous blood were sampled immediately after delivery. Induction to delivery time(IDT), uterine incision to delivery time(IDT), neonatal birth weight and Apgar score were measured. The patient was interviewed to evaluate the incidence of awareness three days after operation. Our results were as follows; There were statistically significant differences between three groups in maternal PaO2, but there were no statistically significant differences between three groups in umbilical arterial and venous oxygenation. Induction to delivery time(IDT) in group 1 was significantly short, compared to group 2 and 3, but uterine incision to delivery time(UDT) was not statistically difference between three groups. The condition of the neonates at birth was generally good except one in group 2. But, this neonate recovered as 5-min Apgar score of 9 after aspiration of amnionic fluid and oxygen administration. Two patients reported dreaming, pain recall or fact recall and one of them refused to be administrated the same anesthesia once again, respectively in three groups. In conclusion, the use of FiO2 0.33 is probably safe in no fetal distress while the use of FiO2 1.0 results in no increase of oxygen partial pressure of umbilical artery and vein, but it guarantees the safe method in the case of suspecting fetal depression. Our anesthetic method was not enough to prevent the awareness. So, further study about not only deep, but also safe anesthetic method is justified.

One - Lung Anesthesia for the Thoracoscopy / 대한마취과학회지

One lung ventilation with a double lumen endobronchial tube during thoracic anesthesia is necessary for the protection of the healthy lung from eontamination by spilage of aecretion from the diseased lung and for offering acceptable condition for the surgeon. In this study, 15 ASA Class 1 & 2 patients who were scheduled for thoracoscopy by one lung ventilation were selected. they were intubsted with a double lunen endobmnchial tube and were ventilated with 100% oxygen. Arterisl blood gases were analysed, and mean arterial pressure and pulse rate were measured at tbree stages (stage I: two-lung ventilation after anesthetic induction and intubation, and 15 min after positioning to lateral decubitus, stage IL: one-lung ventilation, 15 min after lung collapse, and stage III: two-lung ventilation, 15 min after reinflation of operative lung ). Arterial blood gas analysis shows tbat pH and base excess decreased significantly at stage III compaired with those of stage I (p<0.05). Arterial oxgen tension decreased significantly at stage II but was not signifieant clinically, and arterial carbon dioxide tension and oxygen saturation did not change signifieantly at all stages. Mean arterial pressure increased significantly at stageII compaired with that of stage I (p <0.05) without clinical significance, and heart rate also incre significantly at stage III compsired with that of stage I (p<0.05) without clinical significance. We concluded that when thoracoscopy was performed in lateral decubitus poaition by use of one-lung ventilation with 100% oxygen.