Effects of Insufflation on Hemodynamics and Arterial Blood Gas during Thoracoscopic Surgery / 대한마취과학회지

BACKGROUND: To visualize adequately the intrathoracic structures, creation of an artificial pneumothorax by carbon dioxide (CO2) insufflation under positive pressures has been advocated during thoracoscopic surgery. We hypothesized that positive-pressure insufflation during thoracoscopy would cause significant hemodynamic and ventilatory compromise. METHODS: Thirty patients underwent general anesthesia with a single lumen endotracheal tube and placement of an arterial line. Noninvasive cardiac output monitoring was done on both the side of the neck and chest. Baseline measurements of hemodynamic indices and arterial blood gas analysis (ABGA) were taken before CO2 insufflation. Data was obtained at 5 minutes after CO2 insufflation. ABGA was taken 5 minutes after CO2 deflation. RESULTS: Insufflation of CO2 resulted in an increase in heart rate (HR), mean arterial pressure (MAP), and systemic vascular resistance index (SVRI). Whereas cardiac index (CI), accelerated contractility index (ACI), PH, and arterial oxygen saturation (SaO2) were decreased. CONCLUSIONS: Positive pressure insufflation of CO2 during thoracoscopy resulted in hemodynamic and arterial blood gas changes. Therefore, we propose that low pressure (< 10 mmHg) insufflation is a safe adjunct to routine thoracoscopic surgical procedures.

Effect of Hepatic Blood Flow Occlusion on Electrolyte and Arterial Blood Gas during Hepatic Resection / 대한마취과학회지

BACKGROUND: Temporary occlusion of hepatic blood inflow and vascular exclusion are effective for reduction of intraoperative bleeding which is a major problem during hepatic resection. But it might be suggested that they resulted in hemodynamic, electrolyte and blood gas changes. This study was designed for investigating those changes during liver resection using portal triad clamping and/or right, left or both hepatic vein clamping. METHODS: Forty one patients, diagnosed as hepatoma and intrahepatic duct stone, were involved in this study. Duration of liver ischemia was 48.7+/-14.8 min. Hemodynamic variables, electrolytes and arterial blood gas were measured before portal triad clamping and at 10, 30 min after clamping, and 10, 30, and 120 min after declamping, and were compared with each other. Bicarbonate was given when its value was below 20 mEq/L. RESULTS: In the changes of hemodynamics, diastolic blood pressure was decreased significantly at 10 and 30 min after declamping compared with before clamping. In the changes of ABG and electrolytes, pH, bicarbonate and chloride ion were changed significantly at 10 min after clamping compared with before clamping. pH at 10 min after declamping was decreased more associated with increasing anion gap without change of the bicarbonate and increased PaCO2. CONCLUSION: From these results, hemodynamic changes are not remarkable but metabolic acidosis is occurred from 10 minutes after portal triad clamping and more acidotic change was developed at 10 min after declamping, immediate treatment of metabolic acidosis is needed.

The Factor that Determines Mechanical Ventilation during Cesarean Section under General Anesthesia: Weight before pregnancy vs. weight during delivery / 대한마취과학회지

BACKGROUND: During general anesthesia the adult patient's tidal volume is determined by patient's weight. Therefore patients with severe ascites, huge abdominal mass or pregnancy have considerable ventilatory change during the operation because the great change in their body weight, that might cause unwanted respiratory alkalosis or acidosis. The purpose of this study is to identify the effects of such changes in ventilation between pre-delivery and post-delivery periods during the cesarean section. METHODS: Eighteen 36weeks or older pregnant patients (ASA 1), scheduled for elective cesarean section under general anesthesia, are selected for the study. PhysioFlex was used for ventilation. Pre-induction maternal gas analysis were performed in all cases. They were randomly divided into two groups according to the ventilator setting for minute ventilation, one set by pre-pregnant weight (Group 1) and the other by pregnant (term) weight (Group 2). Blood gas analysis were performed 5 minutes after induction and 20 minutes after delivery. End-tidal CO2 and inspiratory airway pressure were also measured. RESULTS: All patients show mild hyperventilation with normal acid-base status at pre-induction period. There were no significant differences in arterial PCO2 value between two groups. Group 1 shows mild metabolic acidosis compared with group 2 (by pH at 20 minutes after delivery). CONCLUSION: Term(just prior to operation) body weight rather than pre-pregnant weight is preferable for ventilator setting in the case of cesarean section under general anesthesia.

Effects of Carbon Dioxide Insufflation on Hemodynamics and Arterial Blood Gas Tension during Thoracoscopy under General Anesthesia / 대한마취과학회지

BACKGROUND: Video-assisted thoracic surgical procedure via thoracoscopy has recently gained popularity, as it avoids a thoracotomy, reducing intraoperative blood loss, postoperative pain, respiratory dysfunction and hospital stay. However, to visualize adequately the intrathoracic structures, creation of artificial pneumothorax by carbon dioxide insufflation during thoracoscopy would cause significant hemodynamic compromise. The aim of this study was to evaluate the effect of CO2 insufflation into the pleural cavity on the hemodynamics and the arterial blood gas tension under general anesthesia. METHODS: Twenty-five patients, after intubation with single lumen endotracheal tube, underwent enflurane (1~2%) and N2O-O2 (1:1) general anesthesia. Before placement of a thoracoscope, the baseline mean arterial pressure and heart rate were obtained. Measurements were taken at 5, 10, and 20 min. after the beginning of carbon dioxide insufflation (3~5 mmHg) and 10 min. after gas evacuation. Blood gas analyses were done before, during CO2 insufflation and after CO2 evacuation. Data were analyzed using Student t-test. RESULTS: Positive-pressure CO2 insufflation (3~5 mmHg) caused a decrease of mean arterial pressure (5~7%) and an increase of airway pressure (1.5 times) and heart rate (13~20%) throughout the gas insufflation period (p<0.05). Blood gas analyses revealed no significant change. CONCLUSIONS: These results suggest that low CO2 insufflation pressures (3~5 mmHg) may cause cardiovascular depression during thoracoscopy. Therefore careful monitorings should be done during this procedure.

The Effects of Combined High-Frequency Jet Ventilation and Conventional Mechanical Ventilation on Cardiovascular and Respiartory System with Pulmonary Edema Induced by Oleic Acid in Dogs / 대한마취과학회지

BACKGROUND: High-frequency jet ventilaion is considered a reliable technique for anesthesia and critical care including respiratory failure but there are adverse reactions such as carbon dioxide retension and dry of respiratory mucosa. The purpose of this study was to confirm the effects of combined high- frequency jet ventilation (HFJV) and converntional mechanical ventilation (CMV) on the cardiovascular system, arterial blood gases tension and mean airway pressure in 9 Korea mongrel dogs with pulmonary edema induced by oleic acid. METHODS: During CMV with 20 breaths/minute, 10 ml/kg of tidal volume and F1O2 1.0, parameers were evaluated (base line value). When pulmonary edema was developed, HFJV was applied initially with 120 breaths/minute, inspiratory time 30% and driving pressure 40 psi F1O2 1.0 for 60 minutes (control value) and thereafter simultaneous use of CMV was applied with the tidal volume of 10 ml/kg and each respiratory rate 8, 4, 2, 1, 0.5 per minute for 30 minutes. RESULTS: Combined application of HFJV and CMV (above repiratory rate 1 per minute) achieved the improvement of oxygenation and carbon dioxide elimination, and Paw was decreased without undesirable effects on cardiovascular system in case of the induced pulmonary edema. CONCUSIONS: From above results we recommanded that HFJV combined with CMV may be a useful method of treatment for respiratory failure.

Differences of Hemodynamics and Arterial Blood Gas in Right and Left Lung Ventilation during Thoracoscopic Surgery with CO2 Insufflation / 대한마취과학회지

BACKGROUNDS: There is difference of blood flow between right and left lung, and it is also affected by positional change. The purpose of this study is to compare hemodynamics and arterial blood gas changes between two lungs in thoracoscopic surgery with CO2 insufflation METHODS: Fourteen thoracoscopic-surgical patient were randomly selected and divided into two groups; Group I : right lung ventilation, Group II: left lung ventilation. Blood gas analysis, blood pressure and heart rate were measured at three stages in lateral position; stage I: 10minutes after two-lung ventilation, stage II: 10minutes after one-lung ventilation and CO2 insufflation, stage III: 10minutes after two-lung ventilation and CO2 deflation. RESULTS: In both groups, blood pressure and heart rate were slightly increased at stage II, pH was decreased, PaO2 and PaCO2 were increased at stage II and stage III. But changes of pH and PaCO2 were greater in left lung ventilation. Arterial oxygen saturation and base excess did not change in all stages. CONCLUSIONS: Thoracoscopic surgery with CO2 insufflation did not increase the risk of hypoxemia if FiO2 is 1.0. However blood CO2 retension is higher in left lung ventilation than in right one. So we have to observe PaCO2 more carefully when the left lung is ventilated.