The Effect of Low Dose Nitroglycerin on Hepatic Blood Flow, Real-time Local Liver Perfusion and Oxygen Extraction Ratio Following the Occlusion and Reperfusion of Hepatic Blood Flow in Experimental Dogs / 대한마취과학회지

BACKGROUND: The Pringle maneuver is traditionally used during the hepatectomy to reduce the blood loss. However, there have been no studies about local liver perfusion (LLP) and oxygen extraction ratio (ERO2) following hepatic ischemia and reperfusion. In this study, the changes in hepatic blood flow (HBF), LLP, ERO2 following hepatic ischemia and reperfusion were observed. And the effects of low dose nitroglycerin (NTG) were observed too. METHODS: A total of 14 mongrel dogs were divided into two groups; control group (C, n = 7), NTG administration group (N, n = 7), NTG administration was started 5 minutes before HBF occlusion. After femoral arterial and central venous catheterization, midline abdominal incision was made. Hepatic artery (HA) and portal vein (PV) were exposed to clamp and declamp. And then doppler flowmeter probes were applied on HA and PV to measure their blood flow and a thermal diffusion microprobe was inserted in the liver parenchyme to measure LLP. RESULTS: The HA and PV blood flow, LLP, and ERO2 were not different between two groups. However, HBF more increased compared to the baseline level in N group after reperfusion. In C group, LLP did not recover after reperfusion. The LLP in N group recovered to the baseline level after reperfusion. CONCLUSIONS: In conclusion, it was observed that the HBF increased and LLP recovered to the baseline level after reperfusion by administration of low dose NTG. The use of low dose NTG is safe and effective for hepatectomy.

Changes in Renal Blood Flow and Real-time Renal Cortical Perfusion According to Low-dose Nitroglycerin and Dopamine Administration Following the Occlusion and Reperfusion of Liver Blood Flow in Experimental Dogs / 대한마취과학회지

BACKGROUND: Pringle maneuver and nitroglycerin (NTG) administration to reduce hemorrhage during hepatectomy may affect renal blood flow (RBF) and renal cortical perfusion (RCP) by reducing blood pressure (BP), perload and others. However, so far there have been no studies on RBF and RCP changes during and after hepatic vascular maneuver in hepatectomy. The purpose of this study was to evaluate the changes in RBF and RCP along with low dose (2 microgram/kg/min) NTG with or without low dose (3 microgram/kg/min) dopamine after the occlusion and reperfusion of hepatic blood flow. METHODS: Eighteen mongrel dogs were divided into three groups according to drug administration after hepatic reperfusion; control group (group C, n = 6), NTG group (group N, n = 6), and NTG with dopamine group (group N-D, n = 6). After femoral arterial and central venous catheterization, a midline abdominal incision was made, and the hepatic artery (HA) and the portal vein (PV) were exposed for clamping and declamping. Thereafter, the right renal artery was exposed, and a doppler probe for measuring RBF was placed around the right renal artery, and a thermal diffusion microprobe was inserted in the renal outer cortex to measure RCP. Hemodynamics, RBF and RCP, were repeatedly measured before and after HA and PV reperfusion. RESULTS: No significant change in heart rate was observed in any group. The BP decreased in all the groups after HA and PV occlusion. In group C, the BP recovered to the baseline level after hepatic reperfusion but not in groups N and N-D. The RBF and RCP decreased in all groups after HA andPV occlusion. The RBF increased compared to baseline in N-D after hepatic reperfusion, and the RCP increased versus baseline in N-D, 10 minutes after hepatic reperfusion. CONCLUSIONS: In conclusion, it was observed that the RBF and RCP increased compared to baseline by administering dopamine during HA and PV reperfusion. Therefore, the prophylactic administration of low dose dopamine during hepatectomy offers an effective method of protecting renal function.

Changes in Hemodynamics and Local Myocardial Perfusion in the Acute Phase of Coronary Reperfusion by Using Nicardipine in Korean Mongrel Dogs / 대한마취과학회지

BACKGROUND: The measurement of perfusion is very important to understanding the physiology in the ischemic and reperfused tissue. However, no studies have been reported using a beating heart with a real time-continuous perfusion measurement system (QFlow(TM)400) to check local tissue perfusion so far. In this study, the changes in hemodynamics and local myocardial perfusion (LMP) after coronary reperfusion with nicardipine (a calcium channel blocker) administration were evaluated. METHODS: A total of 10 mongrel dogs were divided into two groups; group I (control group, n = 5), group II (nicardipine group, n = 5). After femoral arterial, pulmonary arterial and left ventricular catheterization, a left thoracotomy was performed. Next, the left anterior descending coronary artery (LAD) was exposed, and a thermal diffusion microprobe was inserted in the myocardium to measure LMP. RESULTS: In group II, blood pressure and systemic vascular resistance after LAD reperfusion were significantly decreased compared to group I. Cardiac output and stroke volume were more rapidly increased in group II, while left ventricular stroke work was decreased in group II. In group I, the LMP after LAD reperfusion did not recover to the baseline level, but the LMP did recover 20 minutes after LAD reperfusion and was increased more compared to the baseline level at 30 minutes after LAD reperfusion in group II. There were no significant differences in dP/dt between the two groups. CONCLUSIONS: We found that the LMP did not recover to the baseline level in the early state of LAD reperfusion; however, nicardipine administration increased the LMP after the early reperfusion period. Cardiac output and stroke volume were also more rapidly increased when nicardipine was administrated.

The Effect of Preventive Antihypertensive Medication with Nicardipine or Nitroglycerin during Off-pump Coronary Artery Bypass Graft / 대한마취과학회지

BACKGROUND: Tight control of blood pressure in patients with coronary artery disease is critical, especially in the setting of long-standing hypertension and left ventricular dysfunction. With off-pump coronary artery bypass graft (CABG), hypertension usually occurs after the sternotomy, along with an increase in heart rate and filling pressure. In order to minimize hypertension during this period, nitroglycerin or nicardipine was prophylactically infused. METHODS: Twenty patients scheduled to undergo an off-pump CABG from April to August, 2001, were selected and divided into two groups. Group I (n = 10) received nicardipine and Group II (n = 10) received nitroglycerin. Before the skin incision, nicardipine (0.5 - 1.0ng/kg/min) or nitroglycerin (0.5 - 1.0ng/kg/min) was continuously infused. Mean arterial pressure (MAP), heart rate (HR), mean pulmonary artery pressure (mPAP), pulmonary artery occlusion pressure (PAOP), cardiac index (CI), and the systemic vascular resistance index (SVRI) were repeatedly measured at the stages of preincision, postincision, poststernotomy, pericardium open, and 10 min after reperfusion. RESULTS: Although MAP after the sternotomy was increased compared with preincision, it remained within a normal range. Similarly, HR, mPAP, and PAOP were all within a normal range despite increases. The CI was within a normal range at all stages in both groups, and there were no significant difference between the two groups. In group I, the SVRI was significantly decreased compared with group II when pericardium was opened. CONCLUSIONS: Both nicardipine and nitroglycerin were effective in preventing or attenuating hypertension after sternotomy with the hemodynamic stability.

The Effect of Low Dose Nitroglycerin on Hemodynamics and Local Liver Perfusion Following an Occlusion and Reperfusion of the Hepatic Artery and Portal Vein in Experimental Dogs / 대한마취과학회지

BACKGROUND: To reduce massive blood loss during a hepatectomy, many anesthesiologists have used the technique of low central venous pressure maintenance by administration of low dose nitroglycerin (NTG) and/or intravenous fluid reduction. However, so far there have been no studies about local liver perfusion (LLP) changes after hepatic artery (HA) or portal vein (PV) reperfusion in patients receiving nitroglycerin administration. In this study, the changes in hemodynamics and LLP following HA and PV reperfusion along with low dose (2micro gram/kg/min) NTG administration in dogs were observed. METHODS: A total of 20 mongrel dogs were divided into four groups; HA occlusion and reperfusion group (H, n = 5), NTG administration group during the reperfusion on H (H-NTG, n = 5), PV occlusion and reperfusion group (P, n = 5), NTG administration group during the reperfusion on P (P-NTG, n = 5). After femoral and pulmonary arterial catheterization, a midline abdominal incision was made. HA and PV were exposed to clamp and declamp. A thermal diffusion microprobe was inserted in the liver parenchyme to measure LLP. RESULTS: The PV blood flow was not changed after HA occlusion, but HA blood flow increased after PV occlusion. The LLP decreased after HA and PV occlusion. The LLP recovered to the baseline level in group H-NTG after HA reperfusion, but the LLP was more increased compared to the baseline level in group H. In group P, the LLP did not recover after PV reperfusion, but the LLP in group P-NTG recovered to the baseline level after PV reperfusion. CONCLUSIONS: In conclusion, it was observed that the LLP recovered to the baseline level by administration of NTG after PV reperfusion. However, the LLP did not increase after HA reperfusion by administration of low dose NTG.

The Hemodynamic Response of Nicardipine for Hypertension Control during an Off-Pump Coronary Artery Bypass Graft / 대한마취과학회지

Drugs for acute blood pressure control are often required during a cardiovascular operation. Hypertension frequently occurs in an off-pump coronary artery bypass graft. The purpose of this study was to evaluate the effect of nicardipine on hemodynamic change. Twenty adult patients were studied. Anesthesia was induced intravenously with thiopental (4 mg/kg), vecuronium (1 mg/kg), and fentanyl (4microgram/kg), and maintained with 100% O2 and isoflurane 1 1.5 Vol%. When systolic blood pressure rose above 150 mmHg, nicardipine 1 mg was administrated intravenously. Immediately after the nicardipine bolus injection, nicardipine was infused continuously 0.5 4microgram/kg/min. Thereafter, hemodynamic data was recorded. Systolic blood pressure decreased, but cardiac index significantly increased after an intravenous administration of nicardipine and was maintained during the study. There was no incidence of tachycardia. It was concluded that acute blood pressure control using nicardipine could be suitable and safe in patients with an off-pump CABG.

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.

Blockage of Spinal Needle Hole by a Foreign Body: A case report / 대한마취과학회지

In general the appearance of cerebrospinal fluid (CSF) is the most important sign of adequate dura puncture. We experienced an unusual case of spinal failure due to the blockage of a spinal needle hole by a foreign body. After the needle tip penetrated the dura, the stylet was removed, but we could not see a free flow of CSF. We found that a small rubber fragment of the local anesthetic bottle plug was on the spinal needle tip. The reason for this was the aspiration of the local anesthetic with an 18 gauge introductory needle.

Hemodynamic Changes during a Thoracoscopic Thoracic Sympathicotomy in Primary Hyperhidrosis / 대한마취과학회지

BACKGROUND: A right thoracoscopic thoracic sympathicotomy involves the removal of T2 and T3 sympathetic chains. Since part of the sympathetic fibers to the heart traverse these two ganglia, we examined the hemodynamic changes during a thoracoscopic thoracic sympathicotomy in primary hyperhidrosis. METHODS: Noninvasive cardiac output monitoring was done on the both side of the neck and chest. A physiograph for measuring of continuous blood flow was taken from the right index finger and a thermometer was placed in the right palm. Following endotracheal intubation was done with double lumen endotracheal tube, anesthesia was maintained with isoflurane. Sympathicotomies were done for T2-3 during one lung ventilation. Heart rate (HR), mean arterial pressure (MAP), systemic vascular resistance index (SVRI), cardiac index (CI), accelerated contractility index (ACI), end-diastolic index (EDI), and temperature were recorded at arrival, before sympathicotomy, after sympathicotomy at 1, 2, 3, 4 and 5 minuets. The blood flow of the right index finger was recorded before and after the sympathicotomy. RESULTS: Concurrent with initiation of the sympathicotomy, MAP and SVRI were reduced, but the CI was elevated. It was accompanied with right palmar temperature elevation and an increase in the blood flow of the right index finger. CONCLUSIONS: A thoracoscopic thoracic sympathicotomy reduces MAP and SVRI and elevates CI, palmar temperature, and blood flow. We concluded that the hemodynamic changes during a thoracoscopic thoracic sympathicotomy seems to be the peripheral vasodilatation.

Effect of Melatonin on the Changes of Hippocampal Polyamine Content and Neuronal Damage Following Transient Global Ischemia in Mongolian Gerbil: a Study of the Differences of Pre- and Post-ischemic Treatment / 대한마취과학회지

BACKGROUND: We designed this study to examine whether melatonin has a neuroprotective effect against hippocampal neuronal damage following transient global ischemia in a gerbil. Because polyamine is known to participate in the process of ischemic neuronal damage, we examined the influence of melatonin on the polyamine level as well as histology. In particular, we examined the difference between pre- and post-ischemic treatments of melatonin by using the above mentioned parameters. METHODS: Male Mongolian gerbils (60 - 80 g) were used in this study. Transient global ischemia was induced by occlusion of the bilateral common carotid arteries for 3 min with microclips. Melatonin was administered 1 h before or 1 h after occlusion. The animals were dissected 4 days after the occlusion for polyamine measurement by a high performance liquid chromatography (HPLC) and histological evaluation (hematoxylin and eosin staining). A histological examination was performed by a blinded investigator. RESULTS: The hippocampal putrescine (PU) level increased compared to sham-operated animals and the increase of PU was attenuated by melatonin administration (pre- or post-ischemic treatment). Spermidine (SD) and spermine (SM) levels didn't show significant changes after ischemia. Hippocampal neuronal damage in the CA1 region was markedly observed in vehicle-treated animals compared to sham- operated animals. Both pre- and post-ischemic melatonin administration significantly inhibited hippocampal CA1 neuronal damage compared to corresponding vehicle-treated animals (P < 0.01, respectively). CONCLUSIONS: Melatonin attenuates the polyamine response following transient global ischemia and may have putative neuroprotective effects against global ischemia-induced neuronal damage. There is no difference in neuroprotective effects of melatonin between pre- & post-ischemic treatments.

The Effect of Thiopental Sodium, Etomidate and Propofol on Systemic Vascular Resistance and Venous Capacitance during Cardiopulmonary Bypass / 대한마취과학회지

BACKGROUND: The focus of this study is the effects of thiopental sodium, etomidate and propofol on systemic vascular resistance and venous capacitance during cardiopulmonary bypass with constant pump flow. METHODS: Thirty patients (ASA III) scheduled for open heart surgery were randomly divided into three groups. Anesthesia was induced with thiopental sodium 5 mg/kg, fentanyl 5 microgram/kg and vecuronium 1 mg/kg. CPB was conduced with a membrane oxygenator using non-pulsatile flow and moderate hypothermia. When rectal temperature and pump flow had been stable for 5 min, patients randomly received thiopental sodium 4 mg/kg, etomidate 0.3 mg/kg and propofol 2 mg/kg. Perfusion pressure and pump flow were measured 0, 1, 3, 5, 10, 15, 20 and 30 min after administration. RESULTS: The systemic vascular resistance index (SVRI) decreased to 84.3% of the control values after thiopental sodium 4 mg/kg, to 74.7% of the control after etomidate 0.3 mg/kg and to 79.8% of the control after propofol 2 mg/kg. SVRI returned to control value levels 3 min after the administration of thiopental sodium, 20 min after etomidate, and 5 min after propofol. Thiopental sodium, etomidate and propofol reduced venous reservoir volume 1 min after injection and the reduction was sustained throughout the all period of the cardiopulmonary bypass. CONCLUSIONS: The results indicate that thiopental sodium, etomidate and propofol dilate both resistance and capacitance vessels, but there was no correlation between the two vessels.

Hemodynamic Responses and Changes in Oxygen Extraction When Using Amrinone, Dobutamine and Isoproterenol in Cardiac Tamponade-Induced Dogs / 대한마취과학회지

BACKGROUND: Cardiac tamponade is most commonly treated by needle aspiration or surgical drainage. During this process, it may be necessary to temporarily improve cardiac output and to maintain peripheral perfusion by using vasoactive drugs and volume expanders. The purpose of this study is to examine the hemodynamic effect along with oxygen availability on cardiac tamponade induced dogs caused by the use of dobutamine, isoproterenol and amrinone following pentastarch infusion. METHODS: Twenty-four dogs were divided into four groups including a control group (group I), which received only pentastarch 10 ml/kg after artifical tamponade was induced. Following the administration of pentastarch, group II (n = 6) received dobutamine by dripping 10 microgram/kg/min, and then by 20 microgram/ kg/min, group III (n = 6) received isoproterenal (0.5 microgram/kg/min, 1.0 microgram/kg/min) and group IV (n = 6) received amrinone (50 microgram/kg/min, 100 microgram/kg/min). The hemodynamic parameters were measured in seven intervals: baseline, thoracotomy, tamponade, tamponade plus pentastarch, pentastarch plus dripping (1st dose), pentastarch plus drug (2nd injection = two times the 1st dose), and pericardiostomy. Arterial and mixed venous blood gas analyses were carried out in three intervals: after thoracotomy, tamponade, pentastarch plus drug (infusion). Subsequently, oxygen extraction ratios were calculated from the oxygen delivery and oxygen consumption. RESULTS: The heart rate increased significantly during the infusion of isoproterenol (P = 0.032) 1.0 microgram/kg/min in group III and also during the dobutamine infusion when the pericardiostomy (P = 0.028) was performed in group II. Compared to the control group, cardiac output increased significantly in group II from the infusion of the 1st dose and also in group III with the 2nd dose infusion but there were no significant changes in group IV. Although the average intrapericardial pressure was 0.93 mmHg in each group and was increased to 8.23 mmHg during the induced tamponade, no significant changes occurred in the groups with drug infusion. The oxygen extraction ratio fell significantly in the groupII, III and IV during the drug infusion. CONCLUSIONS: As results of this study, it was concluded that the most effective hemodynamic improvements during the induced cardiac tamponade occured in group II with pentastarch-dobutamine while the least effective combination occurred in group IV with pentastarch-amrinone.

Effect of propofol, an intravenous anesthetic agent, on KATP channels of pancreatic beta-cells in rats

ATP-sensitive potassium channels (KATP channels) play an important role in insulin secretion from pancreatic beta cells. We have investigated the effect of propofol on KATP channels in cultured single pancreatic beta cells of rats. Channel activity was recorded from membrane patches using the patch-clamp technique. In the inside-out configuration bath-applied propofol inhibited the KATP channel activities in a dose-dependent manner. The half-maximal inhibition dose (ED50) was 48.6+/-8.4 micrometer and the Hill coefficient was 0.73 0.11. Single channel conductance calculated from the slope of the relationship between single channel current and pipette potential (+20~+100 mV) was not significantly altered by propofol (control: 60.0+/-2.7 pS, 0.1 mM propofol: 58.7+/-3.5 pS). However, mean closed time was surely increased. Above results indicate that propofol blocks the KATP channels in the pancreatic beta cells in the range of its blood concentrations during anesthesia, suggesting a possible effect on insulin secretion and blood glucose level.

Hemodynamic Changes and Clinical Symptoms Resulting from Stellate Ganglion Block / 대한마취과학회지

BACKGROUND: Stellate ganglion block (SGB) is the most common nerve block procedure in pain clinics. To evaluate changes in the hemodynamics and peripheral blood flow on the affected extremity after SGB, SGB was performed unilaterally one at a time on the right and left stellate ganglions by injecting 1% mepivacaine 10 ml without epinephrine in a designated healthy man. METHODS: SGB was repeated 16 times in one subject (right side SGB: 8, left side SGB: 8) by the same clinician. The mean arterial pressure (MAP), heart rate (HR), cardiac index (CI), systemic vascular resistance index (SVRI) and peripheral blood flow were measured in the supine position before (control), and 3, 6, 9, 12, and 15 minutes after SGB using thoracic electrical bioimpedence (Bioz system A-10043, Cardiodynamics, USA), sphygomanometer, and flow meter. RESULTS: The values after SGB including MAP, HR, CI, and SVRI increased slightly compared to the control value. However, peripheral blood flow increased significantly (p < 0.05). The SGB did not affect systematic hemodynamics and the comparison between left and right SGB in hemodynamic changes were not clinically significant. Following SGB, ptosis (100%), nasal stiffness (100%), skin temperature elevation (100%), hoarseness (100%), numbness (81%), dizziness (25%), and swallowing difficulty (25%) were observed. CONCLUSIONS: We concluded that SGB showed to be a hemodynamically safe clinical technique.

Electronmicroscopic Changes of Rat's Sciatic Nerve after Phenol Injection or Drip / 대한마취과학회지

BACKGROUND: Phenol is the most commonly used neurolytic agent for the management of intractable somatic pain, but side effects such as motor dysfunction and potential loss of bladder or rectal sphincter function develop following their application. This study observed functional changes of hind limb and neuropathologic changes in the sciatic nerve after phenol application, highlighting the time of nerve regeneration. METHODS: Functional changes in hind limbs were observed for 6 weeks and the distal part of the phenol-injected or dripped sciatic nerve was severed in 3 rats of each group respectively at 10 minutes, 1 hour, 24 hours, 3 days, 1 week, 2 weeks, 4 weeks and 6 weeks. The pathologic changes in the severed nerves were observed under the electron microscope. RESULTS: The phenol-injected or-dripped hind limbs showed more pronounced motor weakness and more obvious gait changes. About 2 weeks after the phenol application, gradual improvement of gait changes began, and after 6 weeks, motor weakness and gait changes were no longer perceptible. In the group with phenol injection, at 10 minutes after injection, destructive lesions were confined to unmyelinated fibers and the myelin sheath of small myelinated fibers. On the 3rd day and at 1 week, pathologic changes on axonal fibers and Schwann cells were in progress with phagocytosis in spite of myelin restitution. From 2 to 4 weeks, axonal regeneration and remyelination appeared concurrent with myelin disintegration and axonolysis, and histologic findings at 6 weeks were similar to those of the control group. In the group with phenol drip, the histologic changes in the sciatic nerve were very similar to the injection group. CONCLUSIONS: These results suggest that histopathologic lesions after a phenol application on the peripheral nerves are not influenced by application methods. The progress of histopathologic changes is obvious according to the time interval following the phenol application. Accordingly, side effectsthat developed following the use of phenol may be improved around the time when the nerve regeneration occurs, between the second and fourth weeks after the injection. The course of histopathologic changes and clinical findings following the application of phenol is very similar to the previous experiment using alcohol.

Changes in Hemodynamic and Oxygen Availability with Apnea under Halothane Anesthesia / 대한마취과학회지

BACKGROUND: Varying results of hemodynamic and oxygen parameters in response to hypoxia and/or hypercarbia have been reported. In this study, the effects of apnea on the hemodynamic parameters and oxygen availability were evaluated using ten healthy mongrel dogs. METHODS: After full oxygenation, apnea was induced by disconnecting animals from mechanical ventilation. Hemodynamic parameters, oxygen delivery, consumption and extraction ratio were measured at one minute intervals until the cardiac output was undetectable via the thermodilution method. RESULTS: Blood pressure (BP) increased continually following apnea. Cardiac output (CO) increased during the early of apnea (2 and 3 minute) but decreased thereafter. Systemic vascular resistance (SVR) decreased in the early phase of apnea but subsequently declined. The indices of preload increased steadily following apnea. Changes in heart rate (HR) were compared with changes in CO and oxygen delivery, and was found to increase during the early phase of apnea (2~3 minutes) and decrease thereafter. The oxygen extraction ratio did not change significantly and remained steady 6 minutes after apnea but increased and became irregular thereafter. CONCLUSIONS: These data suggest that early reflex responses such as increased BP were primarily due to increased CO, whereas the late increase in BP was due to the increase of SVR. We conclude that BP is not meaningful variables in evaluating critical hypoxic condition such as apnea, and bradycardia might be caused by decreased CO and severe hypoxemia.

Spinal Anesthesia Using 0.5% Hyperbaric Bupivacine/Fentanyl Mixture for Cesarean Section / 대한마취과학회지

BACKGROUND: The last two decades have seen an increase in the incidence of cesarean section. Spinal anesthesia has been popular in cesarean delivery because of the ease and effectiveness, as well as the rapidity in estabilishing adequate levels of analgesia. The clinical effects of subarachnoid administeration of preservative-free fentanyl were assessed in 30 healthy women who underwent cesarean section with spinal anesthesia using 0.5% hyperbaric bupivacaine. METHODS: Sixty parturients were allocated to group I; bupivacaine (n=30) only and group II; bupivacaine/fentanyl mixture (n=30) in random order. The dose of bupivacaine varied from 9~10 mg depending on the patients height. Maximum level of sensory blockade, time to reach T4 level, incidence of hypotension, time to get complete motor recovery, perioperative analgesic effect and complications were evaluated. RESULTS: There were no differences in maximum level of analgesia, time to reach T4 level and to get complete motor recovery, and incidence of hypotension between two groups. However, duration of analgesia was longer in group II with the bupivacaine/fentanyl mixture (191.9 +/- 77.6 min) than in group I with the bupivacaine alone (74.2 +/- 30.8 min). Spinal anesthesia was excellent in 100% of the fentanyl mixture group but in 80% of the bupivacine only group. CONCLUSION: 0.5% hyperbaric bupivacaine mixed with 25 g fentanyl provided improved perioperative analgesia without affecting the onset of sensory blockade and duration of motor blockade.

Changes of Blood Gases, Plasma Catecholamine Concentrations and Hemodynamic Data in Anesthetized Dogs during Graded Hypoxia Induced by Nitrous Oxide / 영남의대학술지

The sympathoadrenal system plays an important role in homeostasis in widely varing external environments. Conflicting findings, however, have been reported on its response to hypoxia. We investigated the effect of hypoxia an the sympathoadrenal system in dogs under halothane anesthesia by measuring levels of circulating catecholamines in response to graded hypoxia. Ten healthy mongreal dogs were mechanically ventilated with different hypoxic gas mixtures. Graded hypoxia and reoxygenation were induced by progressively decreasing the oxygen fraction in the inhalation gas mixture from 21%(control) to 15%, 10% and 5% at every 5 minutes, and then reoxygenated with 60% oxygen. Mean arterial pressure, central venous pressure and mean pulmonary arterial pressure were measured directly using pressure transducers. Cardiac output was measured by the thermodilutional method. For analysis of blood gas, saturation and content, arterial and mixed venous blood were sampled via the femoral and pulmonary artery at the end of each hypoxic condition. The concentration of plasma catecholamines was determined by radioenzymatic assay. According to the exposure of graded hypoxia, not only did arterial and mixed venous oxygen tension decreased markedly at 10% and 5% oxygen, but also arterial and mixed venous oxygen saturation decreased significantly. An increased trend of the oxygen extraction ratio was seen during graded hypoxia. Cardiac output, mean arterial pressure and systemic vascular resistance were unchanged or increased slightly. Pulmonary arterial pressure(PAP) and pulmonary vascular resistance(PVR) were increased by 55%, 76% in 10% oxygen and by 82%, 95% in 5% oxygen, respectively(p<0.01). The concentrations of plasma norepinephrine, epinephrine and dopamine increased by 75%, 29%, 24% in 15% oxygen and by 382%, 350%, 49% in 5% oxygen. These data suggest that the sympathetic nervous system was activated to maintain homeostasis by modifying blood flow distribution to improve oxygen delivery to tissues by hypoxia, but hemodynamic changes might be blunted by high concentration of nitrous oxide except PAP and PVR. It would be suggested that hemodynamic changes might not be sensitive index during hypoxia induced by high concentration of nitrous oxide exposure.

Hemodynamic Responses to Dobutamine, Hydralazine and Sodium Nitroprusside Following Pentastarch Infusion during Cardiac Tamponade in Dogs / 대한마취과학회지

Background: Cardiac tamponade results in a hemodynamic disorder associated with decreased cardiac output and blood pressure. To improve cardiac output in a subject with cardiac tamponade, cardiotonic drugs and vasodilators with blood volume expander can be used. The purpose of this study was to observe the hemodynamic effects of cardiotonic drugs and vasodilators following administration of plasma expander in the dogs with cardiac tamponade. Method: Three groups of dogs were studied during the induced cardiac tamponade. Following infusion of pentastarch, group I received dobutamine by dripping of 10 microg/kg/min, followed by injection of 20 microg/kg/min, group II received hydralazine (20 mg, 40 mg) and group III received sodium nitroprusside (5 microg/kg/min, 10 microg/kg/min). The heart rate, blood pressure, cardiac output and pulmonary arterial occluded pressure were measured. The atrial transmural pressure was calculated by subtracting intrapericardial pressure from mean atrial pressure. Results: Cardiac output was increased in the groups I and II, but mean arterial pressure was increased in only the group I. Atrial transmural pressure was not changed in all three groups. Conclusion: The most pronounced hemodynamic improvements during the cardiac tamponade is observed in group I with pentastarch-dobutamine combination.

Comparison of Hemodynamic Changes by the Thoracic Electrical Bioimpedance Device during Endotracheal Intubation or Insertion of Laryngeal Mask Airway in General Anesthesia / 대한구급학회지

Introduction: we measured the hemodynamic changes by the thoracic electrical bioimpedance (TEB) device during induction of anesthesia, endotracheal intubation or insertion of layngeal mask airway (LMA). This TEB device is safe, reliable and estimate continuously and invasively hemodynamic variables. METHODS: We measured the cardiovascular response of endotracheal intubation or that of LMA insertion in thirty ASA class I patients. General anesthesia was induced with injection of fentany 1 microgram/kg, thiopetal sodium 5 mg/kg and vecuronium 1 mg/kg intravenously. Controlled ventilation was for 3 minutes with inhalation of 50% nitrous oxide and 1.5 vol% of enflurane before tracheal intubation or LMA insertion in all patients. The patient was randomly assinged to either tracheal intubation group (ET group) or laryngeal mask airway group (LMA group). Heart rate (HR), mean arterial pressure (MAP), systemic vascular resistance (SVR), stroke index (SI) and cardic index (CI) were measured to pre-induction, pre-intubation, 1 minute after intubation, 2 minute, 3 minute, 5 minute, 7 minute. RESULTS: MAP and SVR were decreased effectively LMA group than ET group during 1 minute after intubation, 2 minute, 3 minute, 5 minute, 7 minute (p<0.05). HR was decreased effectively LMA group than ET group between pre-induction and 1 minute after intubation, between 1 minute after intubation and 2 minute after intubation (p<0.05). But, SI and CI were no difference between ET group and LMA group during induction of anesthesia and intubation (p<0.05). CONCLUSION: The insertion of LMA is beneficial for certain patients than endotracheal tube to avoid harmful cardiovascular response in the management of airway during anesthesia.