Heparin-Induced Thrombocytopenia during Continuous Veno-Venous Hemodiafiltration after Total Aortic Arch Replacement: A case report / 대한마취과학회지

Heparin-induced thrombocytopenia (HIT) is an immunologically mediated complication of heparin therapy resulting in the consumption of platelets and a catastrophic thromboembolism. Both the clinical and laboratory features are important for a diagnosis of HIT. There have been 3 case reports of suspected HIT in Korea. However none have satisfied the laboratory features. We experienced a case of HIT, which satisfied both clinical and laboratory features, in a patient who received heparin during continuous veno-venous hemodiafiltration (CVVHD) used to treat acute renal failure that developed after a total aortic arch replacement with a cardiopulmonary bypass. The decreased platelet count and obstruction of extracorporeal filter of CVVHD by the blood clot was observed while receiving unfractionated heparin. The serum from the patient contained the anti heparin-platelet factor 4 antibody, and the condition was thus diagnosed as HIT. Argatroban, which is a direct thrombin inhibitor, was used to treat the thrombosis.

Optimal Dose of Remifentanil to Suppress Cardiovascular Responses to Laryngoscopic Endotracheal Intubation / 대한마취과학회지

BACKGROUND: Laryngoscopic tracheal intubation causes acute hemodynamic changes such as hypertension and tachycardia. Adjuvant opioids during induction have been used to attenuate such responses. The aim of this study was to determine the optimal dose of bolus remifentanil, a newly developed ultra short acting opioid, to suppress cardiovascular responses immediately after laryngoscopic endotracheal intubation in patients anesthetized with N2O-O2-sevoflurane. METHODS: Sixty ASA I or II patients who requiring endotracheal intubation were randomly allocated to one of the four groups; C, R0.5, R1, and R2. Each group received normal saline, 0.5, 1, or 2microgram/kg of remifentanil respectively. Predetermined drugs for each group were administered over 30 seconds after induction of anesthesia with thiopental, rocuronium and 2 vol% of sevoflurane with 50% nitrous oxide. Laryngoscopic endotracheal intubation was carried out 60 seconds after the study drug administration. Mean arterial pressure (MAP) and heart rate (HR) were recorded at pre-anesthesia (PA), pre-intubation (PI) and during 5 minutes after intubation (IT-1 to IT-5). Statistical analysis was done for comparison of time and dose dependent changes among the groups. RESULTS: Baseline values were similar among the groups. IT-1 values did not change compared to PI values in R1 and R2. However, MAP and HR in R2 were significantly lower than PA values during post-intubation period. CONCLUSIONS: Bolus injection of 1microgram/kg of remifentanil blocks MAP and HR elevation after laryngoscopic endotracheal intubation without adverse effects in patients under N2O-O2-sevoflurane anesthesia.

Retrograde Study on Thoracic Percutaneous Vertebroplasty and Kyphoplasty Done by Transpedicular Approach / 대한통증학회지

BACKGROUND: Transpedicular percutaneous vertebroplasty, along with kyphoplasty of the thoracic vertebrae, is technically more difficult than those of the lumbar vertebrae due to the anatomical differences. During the last four years, all the percutaneous vertebroplasty and kyphoplasty of the thoracic vertebrae carried out at our institution were performed using a transpedicular approach; therefore, we tried to find if there were any problems or complications associated with the process. METHODS: The medical records of all the patients who had undergone thoracic percutaneous vertebroplasty or kyphoplasty were retrospectively reviewed. The following were looked up: the procedure name, unipedicular or bipedicular, the level of the thoracic vertebrae treated, and the pre- and postoperative changes in the Visual Analog Scales (VAS), the volume of cement injected and complications. RESULTS: In the last four years, 58 vertebral bodies in 58 patients were treated. Twelve and 46 vertebral bodies were treated by kyphoplasty and vertebroplasty, respectively. A total of 58 mid and lower thoracic levels were treated: T5 (n=1), T6 (n=1), T7 (n=3), T8 (n=4), T9 (n=1), T10 (n=4), T11 (n=14) and T12 (n=30). The mean preoperative and postoperative VAS scores were 8.1+/-1.4 and 5.2+/-1.7, respectively. The mean volume of cement injected was 4.01+/-1.85 ml; 3.18+/-0.60 ml at T5-8 and 4.22+/-2.27 ml at T9-12. There were no clinical complications, such as pedicular fracture or cement leakage. CONCLUSIONS: Although transpedicular vertebroplasty and kyphoplasty at the mid to lower thoracic vertebral bodies is technically difficult compared to that at the lumbar region, the procedures can be performed safely.

Could Modified Thromboelastogram Assess Platelet Inhibition by Aspirin in off Pump Coronary Artery Bypass Surgical Patients and Healthy Volunteers? / 대한마취과학회지

BACKGROUND: Thromboelastogram (TEG) is regarded as a method by which coagulation can be measured during surgery. Off pump coronary artery bypass (OPCAB) surgical patients are routinely placed on aspirin. But conventional TEG could not detect platelet dysfunction by antiplatelet agent. We used modified TEG (addition of heparin and platelet agonists) to determine whether this modified TEG could assess the platelet dysfunction by aspirin in OPCAB surgical patients and healthy volunteers. METHODS: After institutional review board approval and consent, platelet function of 10 OPCAB patients (group 1) and 10 healthy subjects (group 2: before aspirin, group 3: after aspirin) were measured using modified TEG. In each group, TEG parameters (R, K time and MA) were analyzed using paired t-test and one way ANOVA was used to determine the difference between groups. RESULTS: In group 1 (OPCAB patients) and group 2 (healthy subjects, before aspirin), the R and K time were increased significantly with the addition of heparin and then decreased subsequently with the platelet agonists (ADP or collagen) in the presence of anticoagulation (heparin). MA showed a decrease in both groups. This compares with no significant difference in all parameters in group 3 (healthy subjects, after aspirin) with the addition of heparin, ADP and collagen. There were no significant differences in each TEG parameter between groups. CONCLUSIONS: This study suggested that aspirin medication obliterated the effect of anticoagulation and platelet agonists in modified TEG. However modified TEG does not provide a comprehensive and sensitive reflection of platelet inhibition by aspirin. TEG should be supplemented by other methods of platelet function assessment.

The Perioperative Management of Diabetic Patients: A Retrospective Study / 대한마취과학회지

BACKGROUND: Diabetic patients have more chance of requiring surgery than non-diabetic population. Glycemic and metabolic controls are key points in the perioperative diabetic management. A variety of methods have been proposed for the management of diabetics perioperatively, but their effectiveness is still controversial. This study was done to investigate whether diabetic patients are managed appropriately in perioperative period. METHODS: Among diabetic patients referred to anesthesiologic outpatient clinic from August 1997 to September 2002, 85 patients were randomly selected Diabetic duration, medication for diabetic control, concurrent illness and referral surgical department was recorded. In preoperative routine laboratory findings, HbA1c, fasting glucose and postprandial glucose were checked Perioperative glucose control protocols applied to patients were investigated RESULTS: Patients received 1.32 operation per person. Diabetic duration was 12.2 +/- 7.2 years, thirty nine patients had take oral hypoglycemic agent and thirty one patients had received insulin. Mean HbA1c was 8.0 +/- 1.6%, thirty four patients showed above 8.0%. Alberti's regimen was used in fifty five patients and insulin was omitted in fifty six patients. Two patients received insulin of half of usual dose in the morning. Alberti's regimen in major surgery and no insulin in minor surgery were preferred. The composition of Alberti's regimen and target blood glucose level varied. During operation, blood glucose was checked only in fourty four cases. Five of seven postoperative hypoglycemic patients were not checked glucose level during operation. Mortality rate was 7% and major cause of death was sepsis. All of the mortality cases had diabetic cardiovascular and nephrologic complications. CONCLUSIONS: We concluded there is a pitfall in managing diabetic patients requiring surgery. There must be a consensus between surgeon and anesthesiologist about perioperative management of diabetics. Perioperative glucose level should be checked as often as feasible, and insulin supply be continued during operation.

The Effect of the Initiating Time of Patient Controlled Analgesia on the Onset of Postoperative Analgesic Effect / 대한마취과학회지

BACKGROUND: Patient controlled analgesia (PCA) is now a widely accepted method of postoperative pain control. It usually begins at postanesthetic care unit, but it takes time to achieve satisfactory level. We have studied the differences in the onset of analgesic effects between starting PCA preoperatively and starting PCA postoperatively. METHODS: Forty patients for subtotal gastrectomy were randomized to two groups. In group I, we started PCA at postanesthetic care unit, in group II, PCA was begun immediately after the induction of anesthesia. We visited each patient and measured 10 cm-visual analgue scale (VAS) score at 3, 6, 9, 12 and 15 hours after the end of operation. We also measured the time taken from the end of operation to extubation. RESULTS: There were no differences in VAS score between two groups on 3 hour. But at 6, 9, and 12 hour, VAS score was significantly lower in group II (P < 0.05). On 15 hour there was no difference between two groups again. There was no significant difference in extubation time between two groups. Preemptive analgesia was not observed in group II. CONCLUSIONS: We concluded that starting PCA immediately after induction of anesthesia can achieve effective analgesia more rapidly than starting PCA at postanesthetic care unit. VAS score was lower than 3 after 12 hours after the end of operation in group II and we speculated that starting PCA 15 hours prior to operation would maximize the analgesic effect of PCA because there was approximately three hours time difference between the two groups.

Dopamine Concentration and Hemodynamic Effects according to the Methods of Dopamine Dilution / 대한구급학회지

BACKGROUND: Incorrect infusion of dopamine can be potentially life threatening. If the actual volume of a 100 ml intravenous bag or bottle used to mix dopamine solutions is greater than the labeled volume, overdilution of dopamine can occur, resulting in ineffective hemodynamic response. To determine the significance of dopamine overdilution induced by the excessive volume, dopamine concentration and hemodynamic effect were compared in the manually mixed dopamine and the manufactured premixed dopamine. METHODS: For 5% dextrose water (D5W) 100 ml intravenous bottle mixed with 160 mg (4 ml) of dopamine (group 1), D5W 96 ml mixed with 160 mg of dopamine (group 2), premixed dopamine with 1.6 mg/ml of concentration manufactured 2 months ago (group 3), premixed dopamine with 1.6 mg/ml of concentration manufactured 6 months ago (group 4), and D5W 100 ml intravenous bottle mixed with 160 mg (4 ml) of dopamine after removal of 4 ml dextrose water (group 5), dopamine concentration was measured by High performance liquid chromatography (HPLC). Hemodynamic data was obtained from 10 mongrel dogs for each group at baseline (T1), 15 minutes after dopamine infusion at a rate of 3 microgram/kg/min (T2), 8 microgram/kg/min (T3), and 15 microgram/kg/min (T4). RESULTS: Dopamine concentrations of group 1, 2, 3, 4, and 5 were 1.51+/- 0.09, 1.60 +/- 0.10, 1.63 +/- 0.06, 1.57+/- 0.08 and 1.57+/- 0.07 mg/ml, respectively. Group 1 showed a significantly low concentration (p< 0.05). There was no significant differences in all hemodynamic data between group 1, 2, 3, and 4. In group 1, however, there was no significant increase in both mean blood pressure at T4 and mixed venous oxygen saturation at T3 compared with T1. CONCLUSIONS: The actual volume of D5W in 100 ml intravenous bottle is greater than the labeled, and therefore can cause significant overdilution of dopamine. Premixed dopamine, however, has the same concentration and hemodynamic effects as the dopamine mixed manually but precisely.

Use of Preoperative Transthoracic Echocardiography to Predict the Prognosis after Off-Pump Coronary Artery Bypass Grafting / 대한마취과학회지

BACKGORUND: Echocardiography is usually performed for preoperative cardiac evaluation before coronary bypass graft surgery. if the variables detected by this noninvasive method could predict the outcome of the off-pump coronary bypass surgery (OPCAB), it would be very helpful. The purpose of this study is the evaluation of preoperative transthoracic echocardiographic findings as the predictor of OPCAB outcome. METHODS: We evaluated the relationships between preoperative variables identified by the transthoracic echocardiography and postoperative outcomes. RESULTS: Among the doppler findings trans-mitral flow shows no relationship with the postoperative outcome. But, left ventricular mass had the predictability of postoperative time of extubation, iCU stay, and hospital stay. CONCLUSiONS: Left ventricular mass can be used to predict the outcome after OPCAB and There are the need of further study to find out the reason the left ventricular mass show relationship with the postoperative outcome.

Effects of Pinacidil, Tetrathylammonium and Glibenclamide on Hypoxic Vasoconstriction in Isolated Perfused Rabbit Lungs / 대한마취과학회지

BACKGROUND: This study investigated the effects of the K+ channel opener, pinacidil on hypoxic pulmonary vasoconstriction in isolated perfused rabbit lungs. In order to evaluate the vasodilatation mechanism of K+ channel opener, we also studied the effects of two K+ channel blocker, tetraethylammonium (TEA), a Ca2+ activated K+ channel blocker and glibenclamide (GLB), an ATP-sensitive K+ channel blocker. METHODS: Isolated lungs from white rabbits were ventilated with a normoxic gas (21%O2-5%CO2-74%N2) and a hypoxic gas (3%O2- 5%CO2-92%N2) alternatively, and then perfused with blood-containing perfusate solution. After a hypoxic pressor response (HPR) had been obtained, various drugs were added to the perfusate reservoir to achieve the predetermined circulating concentration, and the influences of the drugs on HPR were then tested. RESULTS: Pinacidil (0.3-6.0 mcM) produced a dose-dependent pulmonary vasodilation on hypoxic ventilation challenge. TEA (1 mM) caused pulmonary vasoconstriction in normoxic ventilation and potentiated a hypoxic pressor response. When the hypoxic pressor response was potentiated by TEA, pinacidil (1.0, 3.0 mcM) reduced the contraction, but GLB did not cause pulmonary vasoconstriction under normoxic ventilation, potentiate a hypoxic pressor response. CONCLUSIONS: Piacidil is capable of opposing the pulmonary responses of acute hypoxia. Moreover the effects of TEA and GLB suggest that HPV might be mediated through Ca2+ activated K+ channels, not through ATP-sensitive K+ channels.

Thromboendarterectomy in a Patient with Unilateral Chronic Thromboembolic Pulmonary Hypertension / 대한마취과학회지

Chronic thromboembolic pulmonary hypertension (CTEPH) is considered to be an aberrant outcome of acute pulmonary thromboembolism, due to inadequate thrombus dissolution. However, the mechanism of thrombi dissolution failure remains unclear. With respect to inherited thrombophilia, the co-occurrence of natural anticoagulant deficiencies with CTEPH was found to be rare. Pulmonary thromboendarterectomy (PTE) is a potentially curative surgical procedure for CTEPH, but it is associated with considerable mortality due to postoperative complications, such as reperfusion pulmonary edema and right heart failure. The postoperative course after PTE poses a unique series of ventilatory care and hemodynamic management challenges. We present the case of a 42-year-old woman with unilateral CTEPH combined with thrombophilia (Protein S deficiency). Successful PTE was followed by independent lung ventilation with unilateral nitric oxide (NO) inhalation, which resulted in functional improvement without postoperative complications.

Endoventricular Circular Patch Plasty and Intra-operative and Post-operative Care for Patients with Ischemic Cardiomyopathy / 대한구급학회지

BACKGROUND: Endoventricular circular patch plasty (EVCPP)was introduced as an effective reconstructive procedure for ventricular aneurysm and diffuse dilated cardiomyopathy after myocardial infarction.We report the 4-year results of EVCPP in Seoul National University Hospital, the experiences of anesthesia and intensive care for EVCPP in patients with ischemic cardiomyopathy. METHODS: EVCPP has been performed on 31 patients (22 men and 9 women wit h a mean age of 62 years)during 4 years from March 1998 to March 2002.Six patients (19%)were NYHA cl ass II,24 pat i ent s were cl ass III,and 1 pat i ent was cl ass I V.Preoperative and postoperative left ventricular end-diastolic volume (LVEDV),left ventricular end-systolic volume (LVESV),ejection fraction (EF)were determined and compared.Transesoghageal echocardiograghy (TEE)was used to measure the distance between aortic annulus and ventricular aneurysm during EVCPP.Milrinone combined with beta -adrenergics was infused during separation from cardiopulmonary bypass (CPB) and in the intensive care unit. RESULTS: Three patients (10%)needed an intra-aortic balloon pump to wean from CPB and one patient (3%)died in the hospital.Out of 30 survivors,29 patients returned to NYHA class I or II and one patient to class III.Out of 30 patients who underwent echocardiographic study before and after EVCPP,EF increased from 34 +/-9%to 38 +/-10%,and LVEDV and LVESV decreased from 139 +/-43 ml to 94 +/-20 ml and from 90 +/-34 ml to 59 +/-17 ml,respectively. CONCLUSIONS: EVCPP is effective to exclude the akinetic left ventricular segment,thus improving left ventricular function and clinical status of patients with ischemic cardiomyopathy.However, studies concerning postoperative intensive care are warranted to reduce the postoperative complications and morbidity.

A Comparison of the Transoesophageal Doppler and Thermodilution Techniques for Cardiac Output Measurement in Off-Pump Coronary Artery Bypass Surgery Patients / 대한마취과학회지

BACKGROUND: The aim of this study was to compare the accuracy of measured cardiac output using the newly developed esophageal doppler device with that of the thermodilution method using a pulmonary artery catheter. METHODS: In 15 patients undergoing off-pump coronary artery bypass surgery, cardiac outputs were measured at four episodes of surgery; (1) after induction of anesthesia, (2) during dissection of the internal mammary artery, (3) during anastomosis of the left anterior descending artery, and (4) after closure of the pericardium. RESULTS: The bias between the two methods was 0.52 +/- 1.09 L/min. Analysis of the changes in cardiac output from sample episode 1 to 2, from sample episode 2 to 3 and from sample episode 3 to 4, expressed as percent change values, shows no significant differences between the two methods (P > 0.05). CONCLUSIONS: The esophageal doppler accurately reflects changes in cardiac output with time when compared with that of the thermodilution.

The Distribution of Medical Personnel and Medical Equipments in the Intensive Care Units in Korea / 대한구급학회지

BACKGROUND: Not much of the fund is invested in the intensive care unit (ICU) in Korean hospitals since the cost of ICU care is set too low compared to the other medical fields as well as to the other part of the world. This study is designed to support the base of an ICU standard guideline in Korea. METHODS: The questionnaire were sent to 73 ICUs and 24 neonatal ICUs (NICU) of 30 hospitals. Twenty-two of them were teaching hospitals and 8 of them were general hospitals. RESULTS: The ratios of ICU bed number to total bed number were 5.0% and 6.0% in teaching hospital and general hospital respectively. The ratios of NICU bed to total bed were 3.4% and 2.0% in teaching hospital and general hospital respectively. Intensivists were kept in 24.6% of ICU and 36.4% of NICU. Residents were kept in 43.1% of ICU and 45.5% of NICU. The utilization of ICU service was 90% for teaching hospital and 86% for general hospital. The utilization of NICU was 89% for teaching hospital and 3% of general hospital. Nurse to patient ratios varied widely. Most ICUs in teaching hospital showed the nurse to patients ratio of 1 : 4 which was about 32% of total ICU. Most NICUs in teaching hospital showed the nurse to patients ratio of 1 : 5 which was around 20% of total NICU. Most of the ICUs were equipped with central piping system for oxygen and compressed air supply, vacuum system and all the necessary medical gadgets such as mechanical ventilators, ECG monitors, defibrillators, pulse oximeters and infusion pumps. CONCLUSIONS: The distribution of medical personnel as well as medical equipments were varied widely. The variation existed between teaching hospital and general hospital as well as within the teaching hospitals. We need to establish a standard, which grades the level of ICU according to the number of keeping physician, nurse-patients ratio, and the types of medical equipments they have.

Role of Intra-aortic Balloon Pump in High Risk Patients undergoing Off-Pump Coronary artery bypass graft / 대한흉부외과학회지

BACKGROUND: This study aimed to evaluate the usefulness of preoperative placement of intraaortic balloon pump(IABP) in reducing operative risk and facilitating posterior vessel OPCAB in high risk patients with left main disease(>75 % stenosis), intractable resting angina, postinfarction angina, or left ventricular dysfunction(ejection fraction<35 %). MATERIAL AND METHOD: One hundred eighty- nine consecutive patients who underwent multi-vessel OPCAB including posterior vessel revascularization were studied. The patients were divided into group I(n=74) that received preoperative or intraoperative IABP and group II(n=115) that did not receive IABP. In group I, there were 39 patients with left main disease, 40 patients with intractable resting angina, 14 patients with left ventricular dysfunction and 7 patients with postinfarction angina. Ten patients received intraoperative IABP support due to hemodynamic instability during OPCAB. RESULT: There was one operative mortality in group I and two mortalities in group II. The average number of distal anastomoses was not different between group I and group II(3.5+/-0.9 vs 3.4+/-0.9, p=ns). There were no significant differences in the number of posterior vessel anastomosis per patient between the two groups. There were no differences in ventilator support time, length of hospital stay, and morbidity between the two groups. There was one case of IABP-related complication in group I. CONCLUSION: IABP facilitates posterior vessel OPCAB in high risk patients, with comparable surgical results to low risk patients.

Vagal Reflex Induced Bronchospasm / 대한구급학회지

The parasympathetic nervous system has been considered to have an important role in bronchospasm. Although vagal reflexes are well documented in animal models of airway hyperresponsiveness, their importance in asthmatic attacks in man is less documented. We report a case of bronchospasm during sclera buckling operation and we believe that this patient's bronchospasm was induced by the vagal reflex.

The Comparison of Propofol, Isoflurane and Enflurane Anesthesia on Recovery in Day Surgery / 대한마취과학회지

BACKGROUND: Video-assisted thoracoscopic surgery (VATS) is expected to provide fast and comfortable recovery, plus an early return to normal daily activities. This study was carried out to compare the characteristics of recovery after VATS in patients anesthetized with isoflurane, enflurane or propofol. METHODS: Sixty patients undergoing VATS were allocated randomly to receive propofol-N2O, isoflurane-N2O or enflurane-N2O anesthesia. The time between the end of anesthesia and extubation were compared. The orientation, cooperation and degree of sedation in Numeric Rating Scale (NRS) were recorded 5, 10, 30 and 60 min after anesthesia. Recovery was also evaluated by the P-deletion test (PDT) and Digit Symbol Substitution test (DSST) 30, 60 and 120 min after anesthesia for the comparison of the recovery of cognitive and psychomotor function. RESULTS: Early recovery was significantly (P < 0.05) faster in the propofol group (orientation, cooperation and degree of sedation in 10 min) when compared to the isoflurane and enflurane groups, but there was no significant difference in the other parameters of recovery. CONCLUSIONS: The authors concluded that although propofol was associated with faster emergence from anesthesia than enflurane and isoflurane after VATS, recovery of cognitive and psychomotor function were similar in the three anesthetic groups.

The Ventilatory Effect of Hybrid Ventilation in Rabbits

PURPOSE: Intratracheal pulmonary ventilation (ITPV) is developed to decrease dead space ventilation. A reverse thrust catheter (RTC) is introduced into an endotracheal tube through an adapter. Bias gas through the RTC exits from the catheter tip. The flow of gas is redirected outward away from the lung. Gas is intermittently introduced into the lung as tidal volume (VT) by an expiratory valve. ITPV can be combined with pressure control mode, resulting in hybrid ventilation (HV). We hypothesized that HV might decrease VT, compared with volume controlled ventilation (VCV) or pressure controlled ventilation (PCV) alone. METHODS: HV was compared with VCV and PCV in 7 tracheostomized rabbits. We aimed at maintaining PaCO2 levels normal as the respiratory rates (RR) were set at 20, 40, 80, and 120/min. Blood pressure and airway pressures were monitored and dead space ratio was calculated. RESULTS: The dead spaces (VD) of VCV are 30+/-4 mL, 18+/-4 mL, 14+/-4 mL, and 12+/-5 mL and the VD of PCV are 24+/-6 mL, 16+/-3 mL, 15+/-4 mL and 12+/-4 mL at the respiratory rates of 20/min, 40/min, 80/min, and 120/min, respectively. The VD of HV are 13+/-6 mL, 9+/-3 mL, 7+/-2 mL, and 5+/-1 mL, respectively. The VT and PIP of HV are significantly lower than those of VCV and PCV at the same RR. CONCLUSION: It can be concluded that HV can be applied to minimize the airway pressures and dead space ventilation of VCV and PCV.

Anesthetic Management for Awake Craniotomy with Scalp Nerve Block and Propofol/Fentanyl Infusion / 대한마취과학회지

BACKGROUND: If epileptogenic foci are close to eloquent areas of the brain, awakening is needed for functional mapping during seizure surgery. In these cases adequate analgesia and sedation are needed. However sufficient dosage of intravenous anesthetics leads to many side effects. The authors used propofol and fentanyl infusion combined with scalp nerve block to reduce the severity of side effects from overdose of anesthetics. METHODS: The subjects were adult patients who would undergo awake craniotomy. After administering fentanyl 50~100 mcg intravenously, scalp nerve block was done to supraorbital, supratrochlear, auriculotemporal and lesser and greater occipital nerves of the surgical side with 0.25% bupivacaine containing 1 : 200,000 epinephrine. The anterior temporal region was infiltrated with the same local anesthetics. Oxygen was given by nasal cannula. During operation fentanyl was infused. Propofol was infused except during the awake period. Invasive arterial blood pressure, end-tidal CO2 and respiratory rate were monitored throughout the operation and arterial blood gas analysis was done intermittently. RESULTS: During total anesthesia time (410.3 39.9 min) propofol 16.2 6.3 mg/kg and fentanyl 11.9 3.7 mcg/kg were administered. The results of scalp nerve block were satisfactory. Brain swelling and transient decrease in respiratory rate were noticed in six patients and oxygen desaturation to 94% in one patient. All the patients were cooperative and the above problems were solved by reducing drug infusion rates. CONCLUSIONS: Propofol and fentanyl infusion with scalp nerve block may be an adequate method of anesthetic management for awake craniotomy.

Effects of Sodium Nitroprusside-induced Hypotension under Acute Normovolemic Hemodilution on the Cardiovascular System and Systemic Oxygen Balance in Dogs / 대한마취과학회지

BACKGROUND: To decrease homologuous transfusion and bleeding, Acute Normovolemic Hemodilution (ANH) may be combined with induced hypotension. 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 hemodynamics and systemic oxygen balance. METHODS: In 6 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 Sodium Nitroprusside (SNP). Various hemodynamic parameters were measured before and after ANH and 15, 30, 45 and 60 minutes after induction of hypotension and 15 minutes after the end of hypotension. RESULTS: Heart rate was not changed significantly throughout the study. Central venous pressure increased significantly after ANH but decreased to the initial value after induced hypotension. Systemic vascular resistance showed significant decrease after ANH, more significant decrease after induced hypotension and slight increase after discontinuation of SNP. Cardiac output increased markedly by ANH and maintained during induced hypotension. Oxygen flux decreased significantly after ANH but slightly increased after induced hypotension. Oxygen consumption and Oxygen extraction ratio were maintained throughout the study. There were no acidemia and hypoxemia throughout the study. CONCLUSION: The combined use of ANH and induced hypotension with SNP is safe in the aspect of cardiovascular system and systemic oxygen balance.

Attenuating Effect of cAMP on Hypoxic Pulmonary Vasoconstriction in the Isolated Perfused Rat Lungs / 대한마취과학회지

BACKGROUND: Pulmonary vessels constrict when they are exposed to hypoxia, unlike other vessels. It is hypothesized that the decreased concentration of cAMP in the hypoxic condition causes this reaction, HPV (hypoxic pulmonary vasoconstriction). When cAMP concentration is increased by either activating adenylate cyclase, using adenosine, or inhibiting the cAMP hydrolysing enzyme, phosphodiesterase type 3, using amrinone, then HPV can be reversed. The aims of this study were to develop HPV in an isolated perfused rat lung preparation, and to investigate the vasodilating effects of adenosine and amrinone on HPV. METHODS: Isolated lungs from male rats (270 330 g) were ventilated with a normoxic gas mixture (21%O2-5%CO2-74%N2) or a hypoxic gas mixture (3%O2-5%CO2-92%N2) alternately, and perfused with calcium-containing perfusate solution. Adenosine (6 x 100-2 microgram, n = 6) and amrinone (5 x 101-3 microgram, n = 6) were mixed to perfusate solution, and the initial hypoxic pressor response { Pin = Pmax (maximum pulmonary artery pressure) - Pin (initial pulmonary artery pressure)} and hypoxic pressor responses after drug administration { Pdrug = Pmax (maximum pulmonary artery pressure) - Pbase (baseline pulmonary artery pressure)} were measured. Meclofenamate was used to block prostaglandin-mediated vasorelaxation. RESULTS: Adenosine did not decrease Pdrug compared to Pin. But amrinone inhibited HPV effectively a with a linear dose-response relationship (r = 0.842, P< 0.05). y = 26.72 x log (x) 35.79y: % relaxation = 100 [ Pdrug/ Pin] 100 , x: amount of drug, microgram, CONCLUSIONS: Amrinone attenuated HPV, and it can be concluded that increased levels of cAMP helpful to relax pulmonary vessels in hypoxic condition.