Effect of airway pressure on lumbar epidural pressure during positive pressure ventilation / 대한마취과학회지

BACKGROUND: The purpose of this study was to measure lumbar epidural pressure (EP) during the insertion of a Tuohy needle under general anesthesia and to evaluate the influence of airway pressure on EP. METHODS: Lumbar EP was measured directly through a Tuohy needle during intermittent positive pressure ventilation in fifteen patients. Mean and peak EP were recorded after peak inspiratory pressures (PIP) of 0, 15, and 25 cmH2O. RESULTS: All measured lumbar EPs were positive, with the pressure increasing during inspiration and decreasing during expiration. Median EP was 6.0 mmHg (interquartile range, 4.0-8.0) at 0 cmH2O of PIP, 6.5 mmHg (4.5-8.5) at 15 cmH2O, and 8.5 mmHg (6.0-10.5) at 25 cmH2O, increasing significantly at 15 cm H2O PIP, and further increasing at 25 cmH2O (P < 0.001). CONCLUSIONS: We demonstrate the influence of increased airway pressure on lumbar EP measured directly through a Tuohy needle. Lumbar EPs were positive, and increasing PIP levels significantly increased lumbar EP.

Comparison of the Clinical Outcomes of Red Blood Cell Transfusion in Cardiac Surgical Patients according to the Hematocrit / 대한수혈학회지

BACKGROUND: Recent studies have shown that blood transfusions, and especially red blood cells, are associated with potential adverse outcomes. This study was designed to investigate the effects of red blood cell transfusion according to the hematocrit on the clinical outcomes after cardiac surgery. METHODS: The 433 patients who were undergoing cardiac surgery were randomized to two groups. One group was transfused red blood cells with a hematocrit of 20%, and the other group was transfused red blood cells with a hematocrit of 20~25%. The amounts of intraoperative and postoperative transfusion and various parameters of the clinical outcomes were checked. RESULTS: In the hematocrit 20% group, and the postoperative hemoglobin and hematocrit were lower than that of the hematocrit >20% group. But there were no differences of the amounts of intraoperative and postoperative transfusion, the use of inotropics, the platelet count, the prothrombin time (PT), the activated partial thromboplastin time (aPTT), the levels of aspartate aminotransferase (AST), the levels of alanine aminotransferase (ALT), blood urea nitrogen (BUN), serum creatinine (Cr), brain natriuretic peptide (BNP) and creatine kinase MB (CK-MB), the extubation time and the ICU stay time between the two groups. CONCLUSION: A hematocrit lower than 20% was tolerated by the cardiac surgical patients and it was not related to the postoperative morbidity and outcomes.

Growth Suppression of Leukemic Cells by Hyperbaric Nitrous Oxide and Methotrexate / 대한마취과학회지

BACKGROUND: Nitrous oxide inactivates cobalamin which is important in the folate-dependent synthesis of thymidylate. Also, methotrexate has the anti-cancer activity. The aim of this work was to determine the optimal pressure and exposure time of nitrous oxide that maximize the suppression of cancer growth, and the adequate level of methotrexate that maximize the anti-cancer activity of nitrous oxide. METHODS: Acute lymphoblastic leukemic cells and normal lymphocytes were cultured in hyperbaric chamber at 1, 2 and 3 atm of 74% nitrous oxide in 24, 48 and 72 hours at 0, 0.3, 0.5 and 0.7 micrometer of methotrexate, respectively. The results were expressed in the ratio of cell number in hyperbaric chamber to that in the incubator. RESULTS: Compared to control, the growth rates of cancer cells and lymphocytes were 0.767, 0.990 at 1 atm, 0.592, 0.880 at 2 atm and 0.718, 0.864 at 3 atm of nitrous oxide in 24 hours. The survival fraction of cancer cells and lymphocytes were 0.767, 0.894 in 24 hours, 0.800, 0.630 in 48 hours, and 0.571, 0.597 in 72 hours, at 1 atm of nitrous oxide. The growth rates of cancer cells and lymphocytes were 1.012, 0.745 at 0 micrometer, 0.912, 0.696 at 0.3 micrometer, 0.77, 0.647 at 0.5 micrometer and 1.133, 0.506 at 0.7 micrometer of methotrexate. CONCLUSIONS: The pressure increase of nitrous oxide significantly suppressed the growth of lymphocyte but not cancer cells. However, growth of cancer cells and lymphocytes were significantly reduced at high concentration of methotrexate and larger exposure time.

A Statistical Analysis of Preanesthetic Consultation in the Pediatric Patient / 대한마취과학회지

BACKGROUND: Adequate pre-anesthetic evaluation could improve both patient outcome and hospital management by reducing the rates of operation delay and cancellation. We undertook this study to contribute to the establishment of a pre-anesthetic evaluation system by studying pediatric patients who had preoperatively consulted the anesthesiology department. METHODS: Data were collected using the EMR (Electronic Medical Record) system. 260 pediatric patients, age limitation 15 years, who had consulted our anesthesiology staff, were enrolled. The age distributions, departments consulted and clinical causes were analyzed. RESULTS: The age distributions were as follow; <1 month: 1.5%, 1 month-1 year: 29.2%, 1-4 years: 23.8%, 5-7 years: 18.1% and 8-15 years: 27.3%. The causes of the consultations were mainly pulmonary (27.3%), cardiovascular (21.9%), gastrointestinal (12.3%), airway (9.6%) problems and other causes (26.5%). The most common diseases were congenital heart disease, prematurity and URI. The major departments consulted were general surgery (16.2%), ophthalmology (15.4%), thoracic surgery (15.0%), plastic surgery (15.0%) and orthopedic surgery (14.6%). CONCLUSIONS: The establishment of a communication system with surgeons concerning patient management guidelines about the common causes of consultations would improve hospital management by reducing the incidences of delay and the cancellation of operations.

The Education Programs of Cardiopulmonary Resuscitation for Resident and their Effects Assessed by Anesthesiologists / 대한마취과학회지

BACKGROUND: The survival rate of cardiopulmonary resuscitation (CPR) is low in Korea. We believe the cause of this low survival rate is caused by the absence of instrumentation, the lack of manpower and by poor education quality of in-hospital CPR. The purpose of this study was to evaluate the current state of resident education with respect to cardiopulmonary resuscitation and its likely effect. METHODS: We surveyed anesthesiologists who attended the Korean Society of Anesthesiologist Congress. The questionnaire items concerned the followings; 1) The type of supplementary materials used during CPR education; 2) The Duration and frequency of CPR education according to resident grades and hospital scales; 3) The actual CPR participation frequency in a year; 4) The composition of the CPR teams in wards and ICUs; and 5) The effectiveness of CPR education as assessed by anesthesiologists. RESULTS: Most of participating anesthesiologists in this survey worked at large hospitals with more than 500 beds. They had received an irregular schedule of CPR education. Most education programs consisted of lectures, and education time was less than 2 hours. The number of actual CPR participations was about 10 per year. Usually the trainees, other than certified anesthesiologists, had resuscitated patients in wards. Most of the responders believed that current education was ineffective. CONCLUSIONS: We conclude that CPR education is not fully effective. If we want to increase the survival rate of CPR, we should pay more attention to the education program and to its utility and training requirements.

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 Angiotensin II on Hypoxic Pulmonary Vasoconstriction in Isolated Rabbit Lung / 대한마취과학회지

BACKGROUND: The isolated lung model is a very useful model in investigation of hypoxic pulmonary vasoconstriction (HPV), and angiotensin II is extensively used in this model. But the exact role of angiotensin II in HPV is not clear in the isolated rabbit lung. Thus we were concerned about the role of angiotensin II in the blood-perfused rabbit lung. METHODS: New Zealand white rabbits (n = 28) lungs were isolated and perfused with a constant pulmonary perfusate flow; acid-base status and temperature were maintained at constant levels. Deoxyglucose (DOG group, n = 7), angiotension II and deoxyglucose (AG-DOG group, n = 7), calcium (CA group, n = 7), angiotensin II and calcium (AG-CA group, n = 7) were administered, and then hypoxic responses were measured. Three ratios were calculated and compared (P alpha: ratio of hypoxic response to pulmonary arterial pressure at normoxia, P beta: ratio of hypoxic response to baseline hypoxic response, P gamma: ratio of pulmonary arterial pressure at hypoxia to pulmonary arterial pressure at baseline). RESULTS: Angiotensin II increased the pulmonary arterial pressure by 14%, and increased HPV. Baseline pulmonary pressure was increased in the AG-DOG group and in the AG-CA group (P<0.05). P gamma significantly increased in the AG-DOG and AG-CA groups (P<0.05). The first HPV increased but the second HPV decreased in the AG-DOG group (P alpha: P<0.05) and in the AG-CA group. P beta showed no difference between groups. CONCLUSIONS: Angiotensin II resulted in an increase of pulmonary arterial pressure in the isolated rabbit lung. One may misinterpret this as an potentiation of HPV, but HPV was not changed by angiotensin II. Therefore we deny the necessity for angiotensin II in the isolated rabbit lung model.

Optimal Point and Angle of Needle insertion in Midline Spinal Puncture in Korean Young Adult Male / 대한마취과학회지

BACKGORUND: in spinal anesthesia, we usually walk over the interspinous space with a repetitive insertion-withdrawal-redirection-advance chain, which is annoying and time consuming, let alone the discomfort of patients. The aim of this study was to offer a guideline for the optimal point and angle of needle insertion performing spinal anesthesia and to strengthen the basis of the practice of spinal anesthesia. METHODS: Twenty men were evaluated for this study. While in a head-to-knee position, a simple X-ray was taken and L2-3, L3-4, and L4-5 interspaces were measured. Two tangential lines were drawn between the upper and lower spinous process and the points where these two lines meet the skin were marked. The perpendicular line from the most prominent point of the spinous process to the skin was checked(S). The distances from S to the cephalic point of the tangential line (D1) and to the caudal point of the tangential line (D2) were measured. Perpendicular lines were drawn on the point where tangential lines meet skin and the angles between perpendicular lines and tangential lines were measured (A1, A2). RESULTS: Mean distance (MD, [D2-D1] / 2) and mean angle (MA, [A1+A2] / 2) were calculated as 3.59+/-0.64cm, 11.9+/-4.75 for L2-3, 3.72+/-0.50 cm, 11.18+/-1.65degree for L3-4, and 3.71+/-0.61cm, 11.03+/-4.95degree for L4-5 (mean+/-SD). CONCLUSiONS: At any lumbar level, we could approach the interspinous space from the insertion point of 3.6-3.7cm caudal from the spinous process and with the angle of the cephalic direction of about 11-12degree optimally. it can be the guideline for the insertion of the needle in spinal anesthesia and we can get some safe margins for insertion from the measured data.

A Statistical Analysis of the Patients in Anesthesia Preoperative Evaluation Clinic / 대한마취과학회지

BACKGROUND: Inadequate preoperative evaluation leads to delay or cancellation of elective surgery. To minimize this problem, we launched an anesthesia preoperative evaluation clinic. We analyzed major causes of referral, requested departments and distribution of age to make guidelines of management and laboratory tests. METHODS: The data was collected based on 6,902 patients referred to the anesthesia preoperative evaluation clinic from August 1997 to February 2002. The number of patients each year, distribution of sex, age, requested departments and clinical causes of referral were analyzed retrospectively. RESULTS: The sex ratio (M/F) was 42:58. Twenty-three percent of the patients were in their 7th decade. Obstetrics and gynecology (24.3%), general surgery (20.7%), and orthopedic surgery (15.4%) were the main requested departments. Major causes of referral were cardiovascular problems (27.5%) and pulmonary problems (21.0%). Irrespective of age and department, the most common consultations were related to cardiovascular or pulmonary problems. Nineteen percent of patients had more than two problems that included diabetes mellitus and hypertension. CONCLUSIONS: We concluded that increases in the number of referral patients and making guidelines related to cardiovascular and pulmonary problems will contribute to reduce delay or cancellation of elective surgery.

In-hospital Pediatric Cardiopulmonary Resuscitation According to Pediatric Utstein Template / 대한마취과학회지

BACKGROUND: The characteristic of pediatric cardiopulmonary resuscitation (CPR) is different from that of adult CPR. It is known that respiratory arrest is more common in pediatric CPR compared to adults. The objective of this study was to report the characteristics of in-hospital CPR according to four pediatric Utstein groups. METHODS: We reviewed all medical records that were coded as CPR, care for arrest, defibrillation/ cardioversion, and ambu in our children's hospital. We classified the patients in 4 groups, isolated respiratory compromise, pure respiratory arrest, respiratory arrest leading to cardiac arrest and cardiac arrest. The data were summarized and analyzed in pediatric Utstein style. RESULTS: In 2001, 138 patients aged less than 15 years were resuscitated in our children's hospital. The success rate after resuscitation was 100% in the isolated respiratory compromise group, and 100% in the pure respiratory arrest, 54% in the respiratory arrest leading to the cardiac arrest group, and 24.8% in the cardiac arrest group. CONCLUSIONS: We conclude that the isolated respiratory compromise group and the pure respiratory arrest have better results than the respiratory arrest leading to the cardiac arrest group and the cardiac arrest group, considering all characteristics.

In-hospital Cardiopulmonary Resuscitation: Incidence and Survival Rate according to the Utstein Template / 대한마취과학회지

BACKGROUND: Cardiopulmonary resuscitation (CPR) is one of the most important medical procedures. However, we could not find any survival rates from in-hospital cardiopulmonary resuscitation in Korea. The objective of this study was to report outcomes according to a Utstein template for in-hospital CPR and to use this report as basic material to enhance our CPR skills and outcome. METHODS: We reviewed all medical records of arrest cases in our hospital in 2001, which were coded as CPR, care for arrest, defibrillation/cardioversion, and Ambu. The data was summarized and analyzed in Utstein style. Most of the data was described in percentage, and the t-test was used to compare survival rate by sex. A P-value below 0.05 was considered significant. RESULTS: In 2001, 218 patients was resuscitated in our hospital and 53 patients (24.3%) survived after CPR. Their mean survival was 10 days. Twenty-seven victims died within the first 24 hours after resuscitation. Nobody was discharged alive from our hospital. The time interval from collapse to CPR was 1.7 minutes, to intubation, 5.62 minutes, to epinephrine injection 7.4 minutes and to defibrillation, 23 minutes. Glascow coma scale and cerebral performance category were less than 8 and 4 for a majority of patients. CONCLUSIONS: In our hospital, we had a low survival rate and quality of life. To improve outcome, we should prepare a better education program and more equipment and well-trained personnel for CPR.

Research on Etomidate Complications Observed during Induction / 대한마취과학회지

BACKGROUND: The properties of etomidate include hemodynamic stability, minimal respiratory depression, cerebral protection, and rapid recovery. However, its drawbacks include temporary inhibition of steroid synthesis, pain on injection, thrombophlebitis, myoclonus, nausea and vomiting. This study was done to discover the incidence of complications which could be observed during induction and the relationship between these complications and the age, sex and weight of Koreans. METHODS: Induction was done by etomidate 0.3 mg/kg and vecuronium 0.1 mg/kg. Pain on injection and hiccup were checked as present or absent. Myoclonus was checked as absent, mild, or severe. RESULTS: The incidence of pain on injection, hiccup and myoclonus were 4%, 10%, and 40% (mild 28%, severe 12%) respectively. There was no association between pain on injection and hiccup or myoclonus. Hiccup and myoclonus had some association (Gamma 0.774). Logistic regression revealed that there was no association between pain on injection or hiccup, and sex, age or weight. Myoclonus had some association with age and weight. The occurrence of myoclonus could be estimated by the following equation. log[ Fj(x) / { 1 Fj(x) } ] = aj 0.061 age 0.019 weight j = 1, 2 As age or weight increased, the myoclonus was more likely to fall at the low end (i.e., absence). CONCLUSIONS: The incidences of the pain on injection, hiccup and myoclonus were 4%, 10% and 40% respectively. The hiccup and the myoclonus had some positive association. The occurrence of myoclonus decreased as age or weight increased.

Cephalic spreading levels after volumetric caudal epidural injections in chronic low back pain

The volumetric caudal epidural steroid injection has been advocated to facilitate the delivery of medications to the lesion site. This study was aimed to examine the actual spreading patterns of this technique, using epidurogram. A total of 32 patients with chronic low back pain accompanied by radiculopathy of various causes (degenerative spondylosis, herniated nucleus pulposus, spondylolisthesis, and spinal stenosis) were included. The volumetric caudal epidural injection of the 10 mL mixture of contrast medium 5 mL, 0.5% bupivacaine 1 mL, triamcinolone 1.5 mL (60 mg) and normal saline 25 mL was performed. Immediately after the cessation of the first spread, the subsequent solution of another 10 mL of contrast medium 5 mL, 0.5% bupivacaine 1 mL and normal saline 4 mL was injected. This procedure was repeated serially until the total volume to be 50 mL. Continuous fluoroscopic imaging was obtained after each injection. Average time taken to complete the study was 37 sec per every 10 mL. The spreading levels of the mixture were distributed mainly at mid to lower lumbar area in the majority of the patients. During the subsequent injections, the levels were not changed significantly. This was thought to be due to the minimal resistance in cephalad direction, anatomic variations and Starling effect of epidural space.

The Effects of Nonspecific Cation Blocker Gadolinium on Hypoxic Pulmonary Vasoconstriction in the Isolated Rabbit Lung / 대한마취과학회지

BACKGROUND: Hypoxic pulmonary vasoconstriction (HPV) is unique to pulmonary circulation. Recent hypotheses have emerged indicating that O2 levels per se can regulate ion channel activity. The modulation of both cation channels differs according to the conduit or resistance pulmonary vessel type. However, it is not yet studied that the cation channel blocker has the same effect in an animal experimental model, which can exclude several factors that may influence on HPV. The purpose of the present study was, therefore, to determine the effect of nonspecific cation blocker, Gadolinium, on HPV in a rabbit model of isolated lung perfusion. METHODS: In adult white rabbits (n = 6), lungs were isolated and perfused with the constant pulmonary perfusate flow. Acid-base status and electrolytes of perfusate also constantly maintained. Thirty minutes after, baseline hypoxic pulmonary vasoconstriction (HPV) was measured as the difference of pulmonary artery pressure between a period of 21% normoxic gas inhalation and that of 3% hypoxic gas inhalation. After another thirty minutes, Gadolinium 50microgram were mixed to the perfusate, and then HPV were measured three times. After then Gadolinium 100, 200, 400microgram were mixed to the perfusate and HPV were measured. RESULTS: Gadolinium decreased the HPV response according to the dose. The ED50 of the response was 143microgram/100 ml. CONCLUSIONS: The regulation of HPV is based on the cation channel in the isolated rabbit lung.

Effects of Metabolism Inhibited by Deoxyglucose on Hypoxic Pulmonary Vasoconstriction in the Isolated Rabbit Lung / 대한마취과학회지

BACKGROUND: Hypoxic pulmonary vasoconstriction (HPV) is a defense mechanism to maintain adequate oxygenation. It has been reported that metabolism inhibition augments HPV. The purpose of the present study was, therefore, to determine the effect of metabolism inhibition on HPV in a rabbit model of isolated lung perfusion with exclusion of the influential factors on HPV. METHODS: In adult rabbits, lungs were isolated and perfused with a constant pulmonary perfusate flow. Acid-base status and temperature of perfusate was also constantly maintained. Thirty minutes after, the baseline hypoxic pressor response (HPR) was measured as the difference of pulmonary artery pressure (PAP) between a period of 21% normoxic gas inhalation and that of 3% hypoxic gas inhalation. After another thirty minutes, 2-deoxy-D-glucose 100 mg was mixed with the perfusate, and then HPR was measured three times. After checking metabolism inhibition effects, D-glucose 300 mg was mixed to the perfusate to reverse metabolism inhibition, and then HPR was measured three times again. RESULTS: Metabolism inhibition increased the basal PAP compared to the noninhibition state, but it didn't increase HPV response, so the peak PAP responding to hypoxic gas was the same as the noninhibition state. The absolute HPV response was decreased. After reversal of the inhibition state with a large amount of glucose, the basal PAP decreased to the original value and the HPV response recovered to the previous value. CONCLUSIONS: Deoxyglucose-induced metabolism inhibition increased the PAP ventilated with 21% O2, but it didn't increase the PAP ventilated with 3% O2. As a result, the absolute HPV response was decreased.

The Effects of Needle Type, Gauge, Insertion Depth and the Use of Introducer Needle on Spinal or Epidural Needle Deflection / 대한마취과학회지

BACKGROUND: This study was performed to discover how much needle deflection occurs during spinal or epidural block and how it can be reduced. METHODS: A styrofoam block was used to simulate the paraspinal area of the back. A line was drawn perpendicular to the edge. Using the line as a guide, the needles were advanced through the block. Quincke-type needles of 22 and 25 gauge, pencil-type needles of 22 and 25 gauge or Tuohy needles of 17 and 18 gauge were used. Using a block of 6 cm thick, spinal needle was advanced through the introducer with their apertures facing to the same or opposite direction. The deflection from the perpendicular line was measured in mm intervals. RESULTS: Small-gauged and beveled spinal needles had more deflection depending on the block thickness (P < 0.05). However, the deflection of epidural needles was not consistent. When the bevel of the introducer and spinal needle was facing the same direction, the use of an introducer needle decreased the deflection in 22 and 25 G Quicke, and 25 G Whitacre needles (P < 0.05). When facing each other, the deflection was reduced in all the spinal needles (P < 0.05), and reduced more in the 25 G Quicke needles (P < 0.05). CONCLUSIONS: Considering the estimated depth of the spinal canal, needle type, bevel direction, its gauge and the use of an introducer needle, we can take advantage of the deflection phenomenon to reduce post-dural puncture headache and to increase the success rate of a spinal or epidural block.

Epidural Baclofen in the Rabbit: Antinociceptive Effect and Neurotoxicity / 대한마취과학회지

BACKGROUND: Intrathecal baclofen has an analgesic effect. However, the analgesic effect and neurotoxicity of epidural baclofen has not been reported. METHODS: Twenty rabbits, weighing 2.5-3.0 kg, were randomly assigned to three groups; five rabbits receiving 0.9% saline (S), five rabbits receiving 0.1 mg morphine (M), ten rabbits receiving 0.5% baclofen (B). An epidural catheter was inserted at the L(6-7) interspace, and 0.6 ml of saline, morphine or baclofen was injected. Motor and sensory deficits were measured. After two weeks, a spinal cord segment 3 cm on each side of the catheter tip was removed for histological examination. RESULTS: In the M and B groups, no rabbits showed any response of the hindlimbs to the pinch toe test. On light microscopy findings, no inflammation of the meninges or degenerative myelopathy was observed in the S or M groups. In the B group, one rabbit showed local myelopathy of the white matter, and degenerative myelopathy of white and grey matter in the area adjacent to the epidural catheter. However, these changes are focal and minimal, and thought to be ischemic changes due to vascular damage caused by catheterization. Electron microscopy findings showed no morphologic difference between the S and B groups. CONCLUSIONS: Epidural 0.5% baclofen produced antinociceptive effect with slight motor weakness. No definite neurotoxicity was observed after a single epidural injection of 0.5% baclofen in the rabbit.

A Study for Minimum Volumes of Bicarbonate to Cause Precipitation of the Domestic Lidocaines / 대한마취과학회지

BACKGROUND: When local anesthetics for regional anesthesia is used, usually small amounts of bicarbonate are added for rapid onset. This addition gives the mixed solution a more alkaline pH. The following result is an increased unionized form of the local anesthetic and rapid penetration of the drug into tissue. Unfortunately, no data about adequate mixing volumes of domestic lidocaine and bicarbonate is available. METHODS: We examined six mixing pairs of two kinds of 2% lidocaines and three kinds of 8.4% bicarbonates for minimum volumes of bicarbonate to cause a precipitation of 2% 20 ml lidocaine. RESULTS: The mean volumes of bicarbonate to cause precipitation were 1.54 ml for Kwang-Myung lidocaine with Kwang-Myung bicarbonate, 2.90 ml for Kwang-Myung lidocaine with Dae-Won bicarbonate, 2.73 ml for Kwang-Myung lidocaine with Je-Il bicarbonate, 0.97 ml for Je-Il lidocaine with Kwang-Myung bicarbonate, 1.26 ml for Je-Il lidocaine with Dae-Won bicarbonate and 1.39 ml for Je-Il lidocaine with Je-Il bicarbonate. CONCLSIONS: We conclude that the Kwang-Myung lidocaine and the Je-Il lidocaine could cause precipitation when mixing with a smaller bicarbonate volume than foreign textbook recommended.