Induction Time Required for Successful Laryngeal Mask Airway Insertion with Sevoflurane and No Muscle Relaxant in Children / 대한마취과학회지

BACKGROUND: The laryngeal mask airway (LMA) is a simple and safe method for airway control in children.We therefore determined, with meaningful confidence intervals, the time required for successful insertion of LMA in 95% of children with 8 vol% inspired sevoflurane and no muscle relaxant. METHODS: Forty-six patients, ASA physical status I or II, aged 12-108 months old who were scheduled to undergo elective surgery were included.Patients received 5 mg/kg of thiopental and 0.02 mg/kg of atropine intravenously.After loss of the eye lid reflex, we applied an anesthesia circuit prefilled with 8 vol% dialed sevoflurane in 100% O2.A classic LMA (# 2) insertion was attempted after a predetermined induction time.A probit analysis was used to determine the induction time required to achieve 50% and 95% success rates during LMA insertion. RESULTS: A probit model of induction time was predictive of successful intubation (P = 0.155).The induction times needed to achieve 50% and 95% successful LMA insertion were 125 s (95% confidence interval, 52-146 s) and 208 s (178-382 s), respectively. CONCLUSIONS: Ninety five percent success can be obtained with approximately 208 s for ages one to 9 years with classic LMA (# 2).The induction time can vary by LMA size and induction methods.Therefore further studies using different sizes of LMA and induction methods are needed.

Effect of Low Dose Norepinephrine Infusion on Myocardial Oxygen Consumption and Lactate Metabolism / 대한마취과학회지

BACKGROUND: Norepinephrine infusion has been reported to be associated with adverse events in ischemic heart disease due to elevation of afterload and cardiac oxygen consumption. During coronary artery bypass graft, we observed changes of hemodynamic and laboratory parameters in low dose norepinephrine infusion. Also, we investigated effects of norepinephrine on cardiac oxygen metabolism by calculating oxygen consumption and lactate extraction ratio. METHODS: Fifteen patients, ASA PS class IV-V, scheduled for elective coronary artery bypass graft were enrolled in this study. All of the operations were performed under general anesthesia. During harvesting of graft vessels, norepinephrine was infused at the rate of 0.02microgram/kg/min, and then at the rate of 0.05microgram/kg/min. We measured various hemodynamic and laboratory parameters in three periods (baseline, NE 0.02microgram/kg/min, NE 0.05microgram/kg/min). Also we calculated oxygen consumption and lactate extraction ratio of myocardium. RESULTS: In the baseline period(no norepinephrine infusion), oxygen consumption (VO2) is 159.2 +/- 78.6 ml/min, lactate extraction ratio (LER) is 33.1 +/- 13.0%. After norepinephrine infusion at the rate of 0.02microgram/kg/min, VO2 is 157.6 +/- 55.7 ml/min, LER is 29.9 +/- 10.7%. After norepinephrine infusion at the rate of 0.05microgram/kg/min, VO2 is 212.5 +/- 134.5 ml/min, LER is 27.9 +/- 13.4%. Although VO2 and LER are changed in relation to the rate of norepinephrine infusion, there was no statistical significance. CONCLUSIONS: In conclusion, infusion of low dose norepinephrine during coronary artery bypass graft did not produce significant differences in myocardial oxygen consumption and lactate extraction ratio associated with myocardial oxygen balance.

Anesthetic Management of a Patient with Pheochromocytoma in Pregnancy: A case report / 대한마취과학회지

Pheochromocytoma with pregnancy is very uncommon but it is associated with very high maternal and fetal morbidity and mortality. Antepartum diagnosis and proper management can prevent mother and fetus from potentially lethal outcome. Since pheochromocytoma produces and secretes catecholamines, hemodynamic instability can be brought. The aim of anesthetic management is the avoidance of drugs and episodes that will result in hypertensive crisis, and the selection of safe anesthetic measures and anesthetics to mother and fetus. We report a case of pheochromocytoma with pregnancy managed with combined anesthetic technique-epidural anesthesia for cesarean section and general anesthesia for resection of pheochromocytoma 3 weeks after cesarean section. ?

The Effective Dose (ED50, ED95) of Alfentanil to Minimize the Hemodynamic Responses to Laryngoscopy and Endotracheal Intubation / 대한마취과학회지

BACKGROUND: Intravenous alfentanil is one of the effective methods to minimize the hemodynamic responses to laryngoscopy and endotracheal intubation. The purpose of this study is to get effective dose (ED50, ED95) of alfentanil to minimize the hemodynamic responses to laryngoscopy and endotracheal intubation. METHODS: Sixty patients were divided into four groups. Each group received intravenous normal saline 5 ml (Control group), alfentanil 10microgram/kg (Al10), alfentanil 20microgram/kg (Al20) and alfentanil 30microgram/kg (Al30), respectively. Mean arterial pressure (MAP) and heart rate (HR) were measured before and after intubation. We considered the doses of alfentanil effective when the increase in MAP and HR after intubation did not exceed 10% of those before intubation. RESULTS: The ED50 of alfentanil was 12.7 (8.6-16.4)microgram/kg for MAP, 20.1 (15.7-25.6)microgram/kg for HR, respectively. The ED95 of alfentanil was 26.4 (21.7-36.2)microgram/kg for MAP, 38.6 (31.2-56.7)microgram/kg for HR, respectively. CONCLUSIONS: Alfentanil was effective to minimize the hemodynamic responses to laryngoscopy and endotracheal intubation with its ED50 and ED95 as mentioned earlier.

The Amount of Blood Use and Reorganization of Maximal Surgical Blood Order Schedule (MSBOS) in Elective surgery / 대한수혈학회지

BACKGROUND: Overpreparation of Red Blood Cells for elective surgery causes problems, such as returning of blood, inefficient task of the blood bank and waste of blood resources. At The National Medical Center, Maximal Surgical Blood Order Schedule(MSBOS) was organized for the first time in 1994. Recently, blood use is decreased as various transfusion side effects become known, and operation technique and anesthetic methods develop. As a result, we try to revise MSBOS investigating RBC utilization for elective surgery in 2002. METHODS: We investigated RBC utilization for elective surgery, the number of transfused patient, mean blood amount of all patient having been operated in. It was accomplished by referring to anesthesiologic records and blood delivery sheet at The National Medical Center during the 12 months from January through December in 2002. Average number of transfused units per patient of each operation was selected for MSBOS. RESULTS: For one year, the total number of surgery was 3,204, and transfusion was done in 1095 cases of surgery. Average transfusion rate is 34.4%. In 8 kinds of surgery(275 case, 9.3%), average amount of transfusion was under 0.5 unit and Type and Screen(T&S) is transduced for the elective surgery. Except for Cesarean section(C/S), blood use is decreased significantly, compared with the MSBOS organized at 1994. CONCLUSION: We could revise the guidelines for ordering blood on the basis of above results. And MSBOS should be revised at regular intervals, which can decrease blood disuse and medical cost.

Pulmonary Embolism after Spinal Anesthesia Induction for the Surgical Reduction of a Femur Neck Fracture: A case report / 대한마취과학회지

This case involved a pulmonary thromboembolism, which originated from the lower extremity. A 68-year-old female, with a femur neck fracture, underwent spinal anesthesia with 0.5% heavy bupivacaine 11 mg for total hip arthroplasty. Ten minutes after the induction of spinal anesthesia, dyspnea, tachycardia and hypotension appeared. Under the impression of a pulmonary embolism, intubation was done and dopamine and epinephrine were infused. The operation stopped and she was sent to the intensive care unit. On the spiral CT chest angiogram, a pulmonary embolism was found. Deep venous thrombosis was detected in the left lower extremity on the venogram. Heparin therapy was started at a rate of 800 U/hour with a bolus of 5000 U. A consultative operation for the removal of deep vein thrombosis was performed by a chest surgeon, and total hip arthroplasty was performed successfully under spinal anesthesia.

Effect of Clonidine Supplementation on Jugular Bulb Oxygen Saturation and Carbon Dioxide Reactivity during Desflurane Anesthesia / 대한마취과학회지

BACKGROUND: The alpha2-agonist clonidine is an adjunct in general anesthesia. Clonidine constricts cerebral arteries and decreases cerebral blood flow (CBF), but does not alter cerebral metabolic rate (CMR). Thus cerebral ischemia is possible due to CBF/CMR imbalance. This study was designed to prove the effects of clonidine bolus up on CBF and CO2 reactivity in desflurane anesthesia. METHODS: Thirty patients were divided into a clonidine group (n = 15) and a control group (n = 15). Anesthesia was induced with thiopental and pancuronium, and maintained with 50% N2O/O2/ Desflurane. The jugular bulb was cannulated to measure jugular bulb oxygen saturation (SjO2). MAP and SjO2 were measured after induction, after clonidine (2 microgram/kg) or normal saline administration and during hyperventilation. RESULTS: After clonidine administration, MAP decreased from 95.7+/-9.8 mmHg to 81.1+/-6.3 mmHg and was 79.9+/-5.0 mmHg during hyperventilation. In the control group, the corresponding MAP values 95.7+/-9.8 mmHg, 81.1+/-6.3 mmHg and 79.9+/-5.0 mmHg. After clonidine administration, SjO2 was decreased from 84.7+/-3.7% to 81.1+/-5.2%, and was 71.5+/-8.4% during hyperventilation (P = 0.003, P = 0.000) and in control group, there were 95.7+/-9.8%, 81.1+/-6.3% and 79.9+/-5.0%, respectively. CO2 reactivity was expressed as a change of SjO2 per unit change of PaCO2, 1.15+/-1.19%/mmHg versus 1.43+/-0.98%/mmHg (P = 0.49). CONCLUSIONS: During desflurane anesthesia, clonidine-induced constriction of the cerebral arteries was demonstrated but CO2 reactivity was well preserved.

A Study of the Colonization of the Epidural Catheter / 대한마취과학회지

BACKGROUND: Continuous epidural block is an effective method for pain relief. It should be performed with sterile instrumentation to protect against infection by the indwelling catheter. METHODS: Sixty-two patients were examined by means of the presence of infection with a bacterial culture using the pieces of the catheter at the epidural space and subdermal area. We studied the relationship among infection and the indwelling period of the catheter, patient's age and sex, indwelling site of catheter, and rash and induration on the skin. In addition, we observed the relationship between subdermal infection and epidural infection. When bacteria species were identified, an antibiotic sensitivity test was performed. RESULTS: The rate of infection of the epidural space and subdermal area were 25.8% in both. There was no relationship among infection and the indwelling period of the catheter, patient's age and sex, indwelling site of catheter, or rash and induration on the skin. Gram positive coagulase negative Staphylococcus was most commonly observed. Meanwhile the Enterococcus faecalis was most commonly observed at the caudal area. Most colonies of bacterias responded to aminopenicillin and 1st and 2nd generation cephalosporins in the antibiotics sensitivity test. CONCLUSIONS: We recommend that perfect sterilization and effective management of indwelt catheters and skin are required. If necessary, it may be possible to consider the preventive use of antibiotics.

Difference of Jugular Bulb Oxygen Saturation under Propofol, Enflurane and Isoflurane Anesthesia with Hydralazine-induced Deliberate Hypotension / 대한마취과학회지

BACKGROUND: Hydralazine produces cerebral vasodilation, which could appear differently according to which kind of anesthetics was used. SjO2, CBF and AJDO2 have been studied during general anesthesia with enflurane, isoflurane or propofol in 42 patients undergoing spinal surgery. METHODS: Forty-two healthy adult patients were divided into Group P (Propofol-N2O, n = 15), Group E (Enflurane-N2O, n = 15) and Group I (Isoflurane-N2O, n = 12). During the course of the study, the anesthetic concentration was constant. Induced hypotension was provided with hydralazine 20 mg in combination with a continuous infusion of esmolol within 50 - 100ng/kg/min. Arterial blood and jugular bulb blood were obtained and analyzed at normotensive and hypotensive period, respectively. SjO2, was compared within and between groups. RESULTS: SjO2 values of Group P were 66.2 +/- 7.7%, and 81.5 +/- 6.1%, those of Group E were 79.5 +/- 5.6%, and 78.9 +/- 4.9% and those of Group I were 82.0 +/- 6.2%, and 84.4 +/- 3.7% at normotension and hypotension, respectively (P < 0.05 between Group P and Group E, P < 0.05 between Group P and Group I, P < 0.05 within Group P). CONCLUSIONS: When the changes of CBF is assumed with that of SjO2, it may be concluded that CBF increased with hydralazine-induced hypotension in propofol-N2O anesthesia. It may be suggested that hydralazine reverses propofol induced cerebral vasoconstriction.

Reliability of rSO2 to Measure CO2 Reactivity of Cerebral Vasculatures during Desflurane-N2O Anesthesia / 대한마취과학회지

BACKGROUND: Near infrared spectroscopy (NIRS) to monitor regional cerebral oxygen saturation (rSO2) is a noninvasive and simple modal ity in clinical use. The ability of rSO2 as an index of cerebral oxygenation has been well demonstrated. However, the reliability of rSO2 to reflect the changes of cerebral vascular reactivity in the changes of arterial partial pressure of CO2 (PaCO2) has not been established. The aim of this study was to verify the reliability of rSO2 to measure the CO2 reactivity of cerebral vasculatures. METHODS: Twenty healthy adult patients undergoing general anesthesia were enrolled in this study. Anesthesia was induced with propofol and maintained with desflurane/N2O. Respiration was mechanically controlled. The radial artery and jugular bulb were cannulated. The sensor of the NIRS was attached to the ipsilateral forehead. During normocapnia (PaCO2 40 +/- 1.3 mmHg) and hypocapnia (PaCO2 30 +/- 2.4 mmHg), blood was obtained from the radial artery and jugular bulb and analyzed. rSO2 was compared with fSO2 (estimated field oxygen satuation), and the gold standard of tissue oxygen saturation. fSO2 was calculated from the following equation: fSO2 = 0.75 SjO2 + 0.25 SaO2. RESULTS: rSO2 significantly correlated with fSO2 (P = 0.000, r2 = 0.56). A bias of - 5.8% with a precision 12.94% was found. CONCLUSIONS: We concluded that rSO2 can be a reliable predictor to measure CO2 reactivity of cerebral vasculatures during normocapnia and hypocapnia.

Application of Polarized Light Irradiation to Meralgia Paresthetica / 대한마취과학회지

Meralgia Paresthetica is an uncommon and rare entrapment neuropathy involving the lateral femoral cutaneous nerve of the thigh. A lateral femoral cutaneous block has been used in order to alleviate pain and paresthesia in the affected area, but this procedure seems likely to be invasive or involve side effects. We performed a polarized light irradiation (SUPER LIZER HA-550(R), Tokyo Iken Co., Ltd, Japan) for a patient with Meralgia Paresthetica after the patient gave her informed consent. An entry was chosen 2.5 cm below and medial to the anterior superior iliac spine, and irradiation was applied with a cycle of 1 second on and 3 seconds off at 80% output for 8 minutes with 1200 mW output using a type-B probe a sum of eight times. Consequently, mild or moderate pain alleviation was obtained. When compared to pre-irradiation, the patient's symptoms were alleviated and satisfaction was high.