BACKGROUNDS: This study was to evaluate the hemodynamic effects of esmolol and propranolol in the isoflurane-anesthetized dogs. METHODS: Ten dogs were anesthetized with isoflurane, N2O and O2. The hemodynamic parameters were measured as control values and were also measured after 500, 1000, 2000 microgram/kg of esmolol and 0.25, 0.5, 1.0 mg of propranolol were bolus injected intravenously. RESULTS: Heart rate and cardiac output were significantly decreased in both groups compared with control value, but there were no significant differences between two groups. Blood pressure was significantly decreased in the dosage of 1000, 2000 microgram/kg of esmolol group compared with control value and propranolol group, but in propranolol group, no significant changes were found. Systemic and pulmonary vascular resistance were not changed significantly in both groups compared to control value, but in propranolol group, SVR was significantly increased in the dosage of 0.5 and 1.0 mg compared with esmolol group. Central venous pressure, pulmonary arterial pressure, pulmonary capillary wedge pressure, arterial and mixed venous blood pH, oxygen tension, CO2 tension and O2 saturation were not significantly changed and O2 flux, O2 consumption, O2 extraction ratio were also unchanged. CONCLUSIONS: In conclusion, esmolol and propranolol of the usual dosages are less likely to depress the myocardium profoundly during isoflurane anesthesia, and esmolol, compared to propranolol, decreases the blood pressure but changes 2 of cardiac output were not significant between two groups, so it can be used in the hypertensive state or induced hypotensive anesthesia usefully and can also be used conveniently during anesthesia because of its ease of controllability.
Anesthesia ; Anesthetics ; Animals ; Arterial Pressure ; Blood Pressure ; Cardiac Output ; Central Venous Pressure ; Dogs* ; Heart Rate ; Hemodynamics* ; Hydrogen-Ion Concentration ; Isoflurane ; Myocardium ; Oxygen ; Propranolol* ; Pulmonary Wedge Pressure ; Vascular Resistance

BACKGROUND: Because of the difficulty of resuscitation caused by bupivacaine-induced cardiotoxicity, the choice of resuscitation medication is still unclear. We investigated whether insulin can improve outcomes of resuscitation by epinephrine from bupivacaine-induced cardiovascular collapse. METHODS: Twenty-four mongrel dogs were randomly allocated to one of the two groups: an EPI group (n = 12), and an EPI + RI group (n = 12). Sixty minutes after induction of general anesthesia, baseline measurement of hemodynamic parameters and arterial blood gas tension was performed. Bupivacaine infusion was started at a rate of 0.5 mg/kg/min and kept until mean arterial blood pressure fell below 40 mmHg and heart rate 40 beats per minute. At this point, bupivacaine infusion was stopped and resuscitation was started, with epinephrine in EPI group and epinephrine combined with regular insulin in EPI + RI group. RESULTS: Bupivacaine infusion caused significant decreases in mean arterial blood pressure, heart rate, cardiac output, and systemic vascular resistance and increases in mean pulmonary blood pressure, pulmonary capillary wedge pressure, pulmonary vascular resistance, and central venous pressure. The recovery rate of EPI + RI group (8/12) was higher than that of EPI group (2/12). CONCLUSIONS: Combined administration of epinephrine and regular insulin improves outcomes of resuscitation of bupivacaine-induced cardiovascular collapse. Therefore, we believe that prompt administration of insulin should be strongly considered in case of bupivacaine-induced cardiotoxicity.
Anesthesia, General ; Animals ; Arterial Pressure ; Blood Pressure ; Bupivacaine ; Cardiac Output ; Central Venous Pressure ; Depression* ; Dogs* ; Epinephrine* ; Heart Rate ; Hemodynamics ; Insulin* ; Pulmonary Wedge Pressure ; Resuscitation* ; Vascular Resistance

INTRODUCTION: One-lung ventilation (OLV), as a model for adult respiratory distress syndrome, was performed in 8 mongrel dogs, which were made a little hypoxemic by adjusting inspired fraction of oxygen (FIO2) in order to know the effect of nitric oxide (NO) on cardiopulmonary hemodynamics and oxygenation during OLV in lateral position. METHODS: Double-lumen endobronchial tube was intubated through tracheostomy. OLV was performed in lateral position by turning to the side where Swan-Ganz catheter tip was located. FIO2 was adjusted to set SpO2 around 85~90%. After stabilization, cardiopulmonary hemodynamic variables and various oxygenation-related parameters were measured respectively at 5 steps: 1) OLV, 2) OLV and 20 PPM of NO inhalation, 3) OLV, 4) OLV and 40 PPM of NO inhalation, 5) OLV. NO (titrated in N2 tank at concentration of 800 PPM) was administered through low-pressure inlet of ventilator and diluted by inspiratory fresh gas. FIO2 setting of ventilator was slightly increased during NO administration to compensate for FIO2 decrease due to NO titration gas (N2) mixing. NO and NO2 concentration was monitored at the inspiratory limb of breathing circuit by a electrochemical analyzer. RESULTS: There were no difference about hemodynamic variables such as blood pressure (BP), pulmonary arterial pressure (PAP), heart rate (HR), central venous pressure (CVP), pulmonary capillary wedge pressure (PCWP). Neither were different calculated hemodynamic variables such as systemic vascular resistance (SVR), pulmonary vascular resistance (PVR), pulmonary perfusion pressure (PPP), cardiac index (CI), and right ventricular stroke work index (RVSWI). PaO2/FIO2, AaDO2, and S/T were significantly different between step 3 and step 4. But other oxygenation-related parameters such as O2, O2 flux, and O2 ER extraction ratio were not different. CONCLUSIONS: NO inhalation may have a potential for relieving hypoxemia during OLV of dogs in lateral position.
Animals ; Anoxia* ; Arterial Pressure ; Bays ; Blood Pressure ; Catheters ; Central Venous Pressure ; Dogs* ; Extremities ; Heart Rate ; Hemodynamics* ; Inhalation ; Nitric Oxide* ; One-Lung Ventilation ; Oxygen* ; Perfusion ; Pulmonary Wedge Pressure ; Respiration ; Respiratory Distress Syndrome, Adult ; Stroke ; Tracheostomy ; Vascular Resistance ; Ventilators, Mechanical

Backgroud: Bupivacaine blocks the sodium channels enhanced by hypokalemia. Bupivacaine also inhibits the transient outward K+ current (Ito). Insulin, in contrast, enhances Ito and induces hypokalemia. The current study was performed to confirm the efficacy of insulin for the treatment of bupivacaine- induced cardiac depression in dogs. METHODS: After dogs were anesthetized with pentobarbital, 0.5% bupivacaine was administered at a rate of 0.5 mg/kg/min until S O2 decreased to 60% or less, which was defined as the point of cardiac depression in this study. The insulin group (n = 9, 16.9 +/- 3.1 kg) received 2 ml/kg of a mixed solution of regular insulin 30 units and 5% D/W 50 ml, followed by a glucose infusion (50 ml 5% dextrose in water) over 15 min. The control group (n = 9, 15.8 +/- 3.4 kg) received 2 ml/kg of 5% D/W 50 ml, followed by a normal saline infusion over 15 min. Mean arterial pressure (MAP), heart rate (HR), pulmonary artery pressure (PAP), central venous pressure (CVP), pulmonary capillary wedge pressure (PCWP), cardiac output (CO), SO2, blood gas analysis, serum electrolytes, ECG and the local anesthetic concentraton of the blood were taken. RESULTS: Changes in hemodynamic variables and ECG of the insulin group normalized more rapidly than in the control group. There were no statistical differences in serum Na and Ca2 concentratons between the two groups. The serum K concentration of the insulin group was lower than that of the control group after 5 min of resuscitation. The changes in plasma bupivacaine concentration over time were not significantly different between groups. CONCLUSIONS: Insulin is effective in reversing bupivacaine-induced cardiac depression. This study suggests insulin can be considered an immediate treatment for cardiac depression by bupivacaine.
Animals ; Arterial Pressure ; Blood Gas Analysis ; Bupivacaine ; Cardiac Output ; Central Venous Pressure ; Depression* ; Dogs ; Electrocardiography ; Electrolytes ; Glucose ; Heart Rate ; Hemodynamics ; Hypokalemia ; Insulin* ; Pentobarbital ; Plasma ; Pulmonary Artery ; Pulmonary Wedge Pressure ; Resuscitation ; Sodium Channels

Acute normovolemic hemodilution is widely used to conserve blood and to minimize the need for homologous blood transfusion during operation. To evaluate the effects of aeute isovolemic hemodilution on hemodynamics and oxygen transport, pulmonary artery catheter and radial artery catheter were introduced in 8 patients in whom maxillofacial or Wertheim's operation were performed. Blood(estimated from allowable blood loss) was withdrawn from radial artery, and simultaneously replaced by intravenous administration of 5% plasmanate and Hartmann solution. Acute isovolemic hemodilution decreased the hematocrit level from 33.2+/-3.7% to 29.6+/-2.9%. Cardiac output increased significantly, which was associated with decreased systemic vaacular resistance. Oxygen transport and oxygen consumption increased despite a decrease in oxygen carrying capacity. Heart rate, mean arterial perssure, mean pulmonary arterial pressure, central venous pressure, and pulmonary capillary wedge pressure did not change significantly during hemodilution. The results indicate that blood perfusion and oxygenation to tissue were well maintained in the hemodilution of the magnitude used in this study. Therfore it could be concluded that acute isovolemic hemodilution is a safe and relatively simple method of conserving blood and minimizing homologous blood transfusion.
Administration, Intravenous ; Arterial Pressure ; Blood Transfusion ; Cardiac Output ; Catheters ; Central Venous Pressure ; Natural Resources ; Heart Rate ; Hematocrit ; Hemodilution* ; Hemodynamics ; Humans ; Oxygen ; Oxygen Consumption ; Perfusion ; Pulmonary Artery ; Pulmonary Wedge Pressure ; Radial Artery

Acute normovolemic hemodilution is widely used to conserve blood and to minimize the need for homologous blood transfusion during operation. To evaluate the effects of aeute isovolemic hemodilution on hemodynamics and oxygen transport, pulmonary artery catheter and radial artery catheter were introduced in 8 patients in whom maxillofacial or Wertheim's operation were performed. Blood(estimated from allowable blood loss) was withdrawn from radial artery, and simultaneously replaced by intravenous administration of 5% plasmanate and Hartmann solution. Acute isovolemic hemodilution decreased the hematocrit level from 33.2+/-3.7% to 29.6+/-2.9%. Cardiac output increased significantly, which was associated with decreased systemic vaacular resistance. Oxygen transport and oxygen consumption increased despite a decrease in oxygen carrying capacity. Heart rate, mean arterial perssure, mean pulmonary arterial pressure, central venous pressure, and pulmonary capillary wedge pressure did not change significantly during hemodilution. The results indicate that blood perfusion and oxygenation to tissue were well maintained in the hemodilution of the magnitude used in this study. Therfore it could be concluded that acute isovolemic hemodilution is a safe and relatively simple method of conserving blood and minimizing homologous blood transfusion.
Administration, Intravenous ; Arterial Pressure ; Blood Transfusion ; Cardiac Output ; Catheters ; Central Venous Pressure ; Natural Resources ; Heart Rate ; Hematocrit ; Hemodilution* ; Hemodynamics ; Humans ; Oxygen ; Oxygen Consumption ; Perfusion ; Pulmonary Artery ; Pulmonary Wedge Pressure ; Radial Artery

BACKGROUND: The reduction in hematocrit (Hct) by hemodilution tends to cause an increase in cardiac output and a proportional decrease in arterial oxygen content. Additionally the reduction of systemic oxygen delivery (DO2) leads to significant differences in regional blood flow. It is therefore important to characterize the effects of hemodilution on regional oxygen metabolism in individual organs. This study was undertaken to evaluate and compare the effects of acute normovolemic anemia induced by hemodilution. METHODS: Six dogs were anesthetized and mechanically ventilated. Catheters were inserted in the right femoral and pulmonary arteries for blood sampling, and a gastric tonometer catheter was inserted into the gastric lumen. Baseline measurements of systemic hemodynamics, arterial ketone body ratio (AKBR), gastric intramucosal pH (pHi) and arterial lactate were recorded. Hemodilution was then begun by 6% pentastarch and was made in four levels of hematocrit values of 20%, 15%, 10% and 6%. RESULTS: Mean arterial pressures of Hct 10% and 6% was decresaed (P < 0.05) and Hct 15% and 10% increases in cardiac output and pulmonary capillary wedge pressure (PCWP) were observed. Central venous pressure and mean pulmonary arterial pressure were incresed (P < 0.05) at Hct 15%, 10% and 6%. DO2 progressively decreased (P < 0.05). AKBR and pHi began to decreased at Hct 15%. Arterial lactate decrease at Hct 15% and was above 7.4 mmol/L at Hct 6%. CONCLUSIONS: By the measurements of AKBR and pHi, the disturbance of splanchnic oxygenation can be detected early compared to those of O2 in terms of oxygen metabolism and the critical point of DO2 during acute normovolemic anemia induced by hemodilution.
Anemia* ; Animals ; Arterial Pressure ; Cardiac Output ; Catheters ; Central Venous Pressure ; Dogs* ; Hematocrit ; Hemodilution* ; Hemodynamics ; Hydrogen-Ion Concentration* ; Hydroxyethyl Starch Derivatives ; Lactic Acid* ; Metabolism ; Oxygen Consumption* ; Oxygen* ; Pulmonary Artery ; Pulmonary Wedge Pressure ; Regional Blood Flow

In order to evaluate the efficacy of adenosine triphosphate (ATP) in the reduction of left ventricular afterload, we studied the hemodynamic and intrapulmonary shunt effects of intravenous ATP during ethrane-N2O anesthesia. Hemodynamic measurements and arterial and mixed venous blood gas analyses were made in ten patients before (baseline) and 10 min after. ATP infusion at 80,60,120 and 250 mcg/kg/min, respective. The results were as follows: 1) ATP produced a rapid and stable reduction in mean arterial pressure resulting from a marked decrease in systemic vascular resistance. 2) Cardiac index increased significantly by 14, 47 and 72% from baseline value after intravenous infusion of ATP at rates of 60, 120 and 250 mcg/kg/min, respectively. 3) Stroke volume index, heart rate, mean pulmonary arterial pressure, pulmonary capillary wedge pressure and central venous pressure increased significantly, whereas systemic vasular resistance and pulmonary vascular resistance decreased significantly in a dose related fashion during ATP infusion. 4) Intrapulmonary ehunt fraction increased from 5.67% to 6.73, 8.28, 9.85 and 13.38% after intra- venous infusion of ATP at rates of 30, 60, 120 and 250 mcg/kg/min, respectively. 5) Arterial oxygen tension decreased significantly after ATP infusion. These results suggest that ATP might be of value in augmentation of cardiac performance in patients with low cardiac output with high peripheral vascular resistance.
Adenosine Triphosphate* ; Adenosine* ; Anesthesia ; Arterial Pressure ; Blood Gas Analysis ; Cardiac Output, Low ; Central Venous Pressure ; Enflurane* ; Heart Rate ; Hemodynamics* ; Humans ; Infusions, Intravenous ; Lung ; Oxygen ; Pulmonary Wedge Pressure ; Stroke Volume ; Vascular Resistance

BACKGREOUND: Acute normovolemic hemodilution (ANH) is one of the methods of autologous transfusion drawing much attention recently. It is economical and easy to apply to many surgeries requiring multiple transfusions. When used as a drug for induced hypotension, esmolol can avoid many drawbacks of sodium nitroprusside and reduce the amount of intraoperative bleeding with better operative field. Considering recent trend of combining ANH and induced hypotension to increase the success rate of autotransfusion, esmolol-induced hypotension with ANH will be used more frequently in the future. However, tissue oxygen balance may be in danger because of decreased tissue perfusion pressure by induced hypotension and reduced arterial oxygen content by ANH. Thus it is necessary to evaluate effects of induced hypotension combined with ANH on cardiovascular system and systemic oxygen balance. METHODS: In 8 mongrel dogs anesthetized with N2O-O2-enflurane and paralyzed with vecuronium, ANH was performed up to half of initial level of hemoglobin with isovolemic pentastarch infusion, and then mean arterial pressure (MAP) was lowered by 30% of the initial value by intravenous administration of esmolol. Various hemodynamic parameters were measured before and after ANH and 15, 30, 60 and 90 minutes after induction of hypotension and 30 minutes after the end of hypotension. RESULTS: Heart rate began to decrease after ANH and showed significant decrease at 60 and 90 minutes after hypotension compared with initial value. Central venous pressure increased significantly after ANH and hypotension. Pulmonary arterial pressure showed significant increase at 15 and 90 minutes after hypotension. Cardiac output was increased markedly by ANH but began to decrease after hypotension and showed significant decrease at 60 minutes after hypotension. Systemic vascular resistance showed significant decrease after ANH, 15 minutes after hypotension and 30 minutes after discontinuation ofesmolol. Pulmonary capillary wedge pressure and pulmonary vascular resistance showed no significant change. Oxygen flux was decreased markedly by esmolol but recovered after discontinuation of esmolol. Oxygen consumption was maintained throughout the study. Oxygen extraction ratio was increased dly after hypotension. There were no acidemia and hypoxemia throughout the study. CONCLUSION: In conclusion, the results of this study suggest that tissue oxygen delivery might be decreased by anemia but that systemic oxygen balance might be preserved by ANH and induced hypotension within the range used in this study.
Administration, Intravenous ; Anemia ; Animals ; Anoxia ; Arterial Pressure ; Blood Transfusion, Autologous ; Cardiac Output ; Cardiovascular System* ; Central Venous Pressure ; Dogs* ; Heart Rate ; Hemodilution* ; Hemodynamics ; Hemorrhage ; Hydroxyethyl Starch Derivatives ; Hypotension* ; Nitroprusside ; Oxygen Consumption ; Oxygen* ; Perfusion ; Pulmonary Wedge Pressure ; Vascular Resistance ; Vecuronium Bromide

BACKGROUND: The studies related to induced hypotention using propofol were rare. So we studied the effectiveness of propofol as induced hypotensive agent in brain aneurysmal surgery. METHODS: The hemodynamic changes during induced hypotension with propofol (propofol-group) and isoflurane(isoflurane group) were observed in patients undergoing aneurysmal surgery. Twenty patients were allocated randomly to receive propofol induction and maintenance, or thiopental sodium induction and isoflurane maintenance for anesthesia. Both groups also received fentanyl, vecuronium, nitrous oxide and oxygen. These hypotensive effects were evaluated before, during and after induced hypotension. Hemodynamic changes were evaluated by measuring systemic arterial blood pressure, heart rate, central venous pressure, pulmonary capillary wedge pressure, cardiac output, systemic vascular resistance and pulmonary vascular resistance. We also compared the ventilatory effect of hypotensive anesthesia by blood gas analysis. RESULTS: There were no significant changes of heart rate, cardiac output, mean pulmonary arterial pressure, pulmonary capillary wedge pressure, central venous pressure and pulmonary vascular resistance before, during and after induced hypotension in both group. Mean arterial pressure and systemic vascular resistance were significantly decresed during induced hypotension (p<0.05). There were no significant changes of PO2, PCO2, HCO3 , base excess before, during and after induced hypotension in both group. CONCLUSION: Propofol is also an effective hypotensive agent comparable to isoflurane.
Anesthesia ; Anesthetics ; Aneurysm ; Arterial Pressure ; Blood Gas Analysis ; Cardiac Output ; Central Venous Pressure ; Fentanyl ; Heart Rate ; Hemodynamics* ; Humans ; Hypotension* ; Intracranial Aneurysm ; Isoflurane ; Nitrous Oxide ; Oxygen ; Propofol* ; Pulmonary Wedge Pressure ; Thiopental ; Vascular Resistance ; Vecuronium Bromide