The Effect of Maternal Supine or Lateral Tilt Position on Maternal and Neonate Outcome / 대한마취과학회지

BACKGROUND: An aortocaval compression by the gravid uterus in late pregnancy leads to acute hypotension in the mother and decreases uteroplacental blood flow which may affect neonatal outcome. The purpose of this study was to evaluate maternal hemodynamic changes, which affect neonatal outcome under general anesthesia for an elective cesarean section depending on the maternal position-supine or left lateral 15degrees tilting by wedge. METHODS: Forty women undergoing an elective cesarean section under general anesthesia delivered through the supine position or left lateral 15degrees tilting by wedge position randomly. The maternal brachial blood pressure and heart rate were recorded, and the maternal arterial blood, umbilical artery and vein blood were sampled. Induction-to-delivery time (IDT), uterine incision-to-delivery time (UDT), and Apgar scores were measured. RESULTS: The two groups had no maternal hypotension less than 100 mmHg, and there were no significant differences in brachial blood pressure and heart rate of the mother, or acid-base status and Apgar scores of the neonate. CONCLUSIONS: In conclusion, maternal position had no clinical significant effects on maternal brachial blood pressure and heart rate, and neonatal outcome.

Anesthetic Management during Laparoscopic Cystectomy in a Third Trimester Pregnancy: A case report / 대한마취과학회지

Pregnancy, especially in the third trimester, has been considered a contraindication of laparoscopic procedure because the effect of CO2 pneumoperitoneum on the fetus and uterine blood flow was unclear. However, the benefits of laparoscopic surgery such as less stress response and shorter hospital stay are postulated. Laparoscopic surgery may be beneficial in pregnant patients compared to open laparotomy, and the safety of laparoscopic operations in pregnant women is under investigation. The careful anesthetic management and close monitoring of patient and fetus will be helpful in making laparoscopic surgery safer in pregnant patients. We report the anesthetic management for laparoscopic surgery in a third trimester pregnant patient with torsion of an ovarian cyst. We monitored the intestinal mucosal CO2 using Tonocap, because we considered it could represent the uterine perfusion and intestinal CO2 status. Although the arterial and intestinal mucosal CO2 tension increased gradually during the operation, hypercapnia was not remarkable. The respiratory and monitored parameters were stable during the laparoscopic procedure. The patient has maintained uneventful pregnancy and delivered a healthy baby at 41 weeks of gestation.

Blood P50 Calculated from a Single Measurement of pH, PO2 and SO2 under General Anesthesia / 대한마취과학회지

BACKGROUND: The P50 which is the oxygen tension corresponding to 50% saturation at pH 7.40, PCO2 40 mmHg and temperature 37oC is an accepted and useful reference to characterize the oxygen affinity for hemoglobin. This study evaluated the accuracy of P50 calculated from a single measurement of pH, PO2 and SO2 compared with linear regression and sigmoid Emax model in patients undergoing general anesthesia. This study also compared P50 of just after anesthetic induction to P50 of 90 min later. METHODS: This study was conducted in 10 patients undergoing total abdominal hysterectomy. Just after induction of anesthesia, 20G catheter was indwelled at cephalic vein of forearm and venous return was occluded with a tourniquet. After 4 min, 6 blood samples were obtained every one minute. After 90 min, 6 blood samples were obtained with same method. All blood samples were analyzed with blood gas analyzer within 30 min after withdrawal. P50 was calculated from three methods of calculation, linear regression and sigmoid Emax model. The difference between the actural P50 and calculated P50 was evaluated. RESULTS: P50's calculated from three methods were 25.8+/-1.1, 26.1+/-1.1, 26.0+/-1.2 mmHg respectively. P50's 90min after anesthetic induction (26.1+/-1.3, 26.3+/-1.2, 26.2+/-1.2 mmHg) were significantly greater than P50's just after anesthetic induction (25.5+/-0.8, 25.8+/-1.0, 25.9+/-1.1 mmHg)(P90%). Sigmoidicity of oxygen dissociation curves from 10 patients with sigmoid Emax model was 2.78+/-0.13 (mean SD). CONCLUSIONS: The method calculating P50 from a single measurement of pH, PO2, SO2 was relatively reliable to estimate the change of oxygen dissociation curve of a patient. The affinity of hemoglobin to O2 was reduced during general anesthesia.

Changes in Arterial to End Tidal CO2 Difference during Pediatric Open Heart Surgery: Cyanotic vs Acyanotic Congenital Heart Diseases / 대한마취과학회지

BACKGROUND: The arterial to end-tidal carbon dioxide tension difference(Pa-ETCO2) can be increased in patients with congenital heart disease(CHD) and, therefore, end-tidal carbon dioxide tension(PETCO2) does not accurately approximates arterial carbon dioxide tension(PaCO2). The purpose of this study was to evaluate the stability of the Pa-ETCO2 in pediatric patients with congenital heart disease undergoing open heart surgery. METHODS: Forty three children with CHD were studied: twenty two were acyanotic and twenty one were cyanotic. Simultaneous PETCO2 and PaCO2 measurements, as well as pulse rate, blood pressure, pH and arterial oxygen tension(PaO2) were obtained for each patient during four intraoperative events: (1) after induction of anesthesia and before sternotomy, (2) after sternotomy and before cardiopulmonary bypass(CPB), (3) after weaning of CPB, and (4) after closure of sternotomy. RESULTS: The PETCO2 of cyanotic group were lower than that of acyanotic group throughout operation period, and did not change significantly after CPB. Cyanotic children demonstrated a greater Pa-ETCO2 difference before CPB as compared with acyanotic group. In acyanotic group, Pa-ETCO2 difference increased significantly after CPB(P <0.05), whereas it remained unchanged in cyanotic group. CONCLUSIONS: Since cyanotic children had higher Pa-ETCO2 differences intraoperatively and acyanotic children showed an increase in Pa-ETCO2 after CPB, the PETCO2 cannot be the alternative value to estimate reliably the PaCO2 during open heart surgery of pediatric CHD.

The Change of Arterial Blood Gas during High Frequency Jet Ventilation via 14 French Suction Catheter in Microlaryngeal Endoscopic Surgery / 대한마취과학회지

BACKGROUND: It is a routine practice that High Frequency Jet Ventilation (HFJV) is applied through a 14~16 gauge (about 12 French (Fr.)) angiocath. The 14 Fr. suction catheter which is similar to angiocath in its internal diameter is commonly available in the operating room. We evaluated the suction catheter as a carrier of HFJV in point of ventilation, oxygenation and operating field during HFJV at microlaryngeal endoscopic surgery (MES). METHODS: Fifteen adult patients undergoing HFJV via 14 Fr. suction catheter during MES were studied. Time-based arterial blood gas analyses were done before and after HFJV. The movement of operating field was examined using laryngoscopic examination by surgeon and anesthesiologist. We also evaluated complications such as abdominal distension, barotrauma and so on. RESULTS: The mean arterial oxygen tension was maintained above 250 mmHg all the time during HFJV. The mean carbon dioxide tension was less than 51 mmHg. There were no remarkable catheter movement and complications. CONCLUSION: The 14 Fr. suction catheter is a good replacement of angiocath. It provided good operating field, ventilation and oxygenation without complications.

The Difference between Arterial and End-tidal Carbon Dioxide Tension in Anesthetized Patients with Reduced Functional Residual Capacity / 대한마취과학회지

BACKGROUND: It has been known that arterial carbon dioxide tension is 4~5 mmHg higher than end-tidal carbon dioxide tension in healthy adults during general anesthesia. But negative arterial to end-tidal PCO2 difference was reported in pregnant patients undergoing cesarean section. The purpose of this study was to elucidate the difference between arterial and end-tidal PCO2 in anesthetized patients with reduced functional residual capacity. METHODS: 90 patients were divided into 3 groups i.e. control group (n=30), obese group (n=20, body weight more than 20% greater than ideal weight), pregnant group (n=40). All patients had no cardiac or respiratory abnormalities and never smoked. Arterial blood gas analysis and measurement of end-tidal PCO2 were done 20 minutes after induction of anesthesia in control and obese group and just before uterine incision and 20 minutes after fetal delivery in pregnant group. RESULTS: There were significant correlations between arterial and end-tidal PCO2 in all groups. The incidences of negative arterial to end-tidal PCO2 difference were 10% in control group, 40% in obese group, 42.5% in pregnant group (p<0.05). CONCLUSION: From this study, it is concluded that patients with reduced functional residual capacity have more incidences of negativity than normal patients in the values of arterial to end-tidal PCO2 difference during general anesthesia. So when the tight control of PaCO2 is required in patients with reduced FRC, we recommend to measure PaCO2 for better anesthetic management.

The Effects of Trendelenburg Position and Intraabdominal CO2 Gas Insufflation on Cardiopulmonary System during Pelviscopic Surgery under General Anesthesia / 대한마취과학회지

BACKGROUND: Pelviscopic techniques have rapidly increased in therapeutic procedures as well as diagnostic procedures because of the many benefits associated with much smaller incisions than traditional open techniques. But the deliberate pneumoperitoneum with carbon dioxide during pelviscopic surgery may cause some problems-hypercarbia, pneumomentum, subcutaneous or mediastinal emphysema, pneumothorax, hypoxemia, hypotension, cardiovascular collapse and cardiac dysrhythmia. METHOD: We observed the changes of blood pressure (systolic, mean, diastolic), pulse rate, PaCO2, PaO2, peak inspiratory airway pressure and expired tidal volume at 10 minute after induction of general anesthesia (control value), 30 minutes and 60 minutes after insufflation of CO2 and Trendelenburg position. RESULTS: The blood pressure, PaCO2 and peak inspiratory airway pressure were increased significantly than control values (p<0.05). The changes of pulse rate and expired tidal volume were not statistically significant in comparison to control values. The PaO2 was decreased significantly (p<0.05). CONCLUSION: To minimize the risk of CO2 retension and unstability of cardiovascular system during pelviscopy under the Trendelenburg position, we must monitor the vital signs and the arterial blood gas status continuously and carefully.

Does End-tidal PCO2 Reflect Adequately Arterial PCO2 during One-lung Ventilation for Thoracoscopy? / 대한마취과학회지

BACKGROUND: Maintenance of normal arterial carbon dioxide tension (PaCO2) is not generally a problem if the same tidal volume can be maintained when changing from two-lung(TLV) to one-lung ventilation(OLV). However, there have been a few studies on the use of capnography in monitoring the adequacy of ventilation during one-lung anesthesia. We have therefore studied how closely end-tidal PCO2 (PETCO2) values reflect changes in PaCO2 in patients undergoing thoracoscopic sympathectomy during TLV and after transition to OLV. METHODS: We have measured arterial oxygen tension(PaO2), PaCO2, PETCO2, and (PaCO2-PETCO2) in 24 adult, either sex, patients by infra-red spectrometry. They were measured after induction of anesthesia, in supine position(TLVsup), after a lateral decubitus position(TLVlat), at 15 minutes after left OLV(OLVLt), after right OLV(OLVRt), and at 10 minutes in the supine position re-positioned at the end of the operation(TLVrep). Data were analyzed with a one-way analysis of variance with repeated measures followed by multiple comparision. The correlation between PaCO2 and PETCO2 were tested using linear regression. RESULTS: PaCO2 did not significantly change, whereas PETCO2 significantly decreased at OLVLt, OLVRt compared with TLVsup value (OLVLt, 29.7 mmHg OLVRt, 30.5 mmHg and TLVsup, 33.6 mmHg; P0.65, P<0.0006) CONCLUSIONS: In the patients undergoing thoracoscopic sympathectomy with TLV or OLV in the lateral decubitus position, PETCO2 is a reliable estimate of the PaCO2. However, when the operative time is prolonged the arterial PCO2 may be more reliable than PETCO2.

Changes in Airway Pressure, Blood Gas and Postoperative Emesis of 50% N2O in Laparoscopic Cholecystectomy / 대한마취과학회지

BACKGROUND: The use of laparoscopic techniques in general surgery has gained increasing popularity. The small, limited incisions are well accepted by patients and there is the benefit of a faster recovery. But the contribution of N2O to nausea and vomiting is still controversial. This study was undertaken to evaluate the effect of N2O for airway pressure, blood gas and postoperative emesis in laparoscopic cholecystectomy. METHODS: Twenty ASA physical status I, II patients for elective laparoscopic cholecystectomy were randomly divided into two groups. First group (n=10) of patients was anesthetized with isoflurane(0.5~1.5 vol%)-O2 (2 l/min)-air (2 l/min). Second group (n=10) of patients was anesthetized with isoflurane (0.5~1.5 vol %)-O2 (2 l/min)-N2O(2 l/min). After induction of anesthesia, ventilation was controlled with tidal volume 10 ml/kg and respiratory rate 11/min and not changed throughout the operation. After measuring of control value of PaCO2, pH and airway pressures before CO2 insufflation, repeatedly measured at 20 min, 40 min after CO2 insufflation and 10 min after CO2 exsufflation. We observed the patients concerning nausea and vomiting for postoperative period. RESULTS: There were no significant intraoperative differences between the both groups with respect to PaCO2, pH and airway pressures. In the both groups, PaCO2 and airway pressure throughout the operation are significantly increased in comparison to control values. The pH is significantly decreased in comparison to control values. The incidence of postoperative nausea and vomiting was similar in both groups. CONCLUSIONS: N2O had no clinically apparent effects on airway pressure, blood gas and postoperation emesis during laparoscopic cholecystectomy.