The effects of inspiratory to expiratory ratio on ventilation and oxygenation during high frequency partial liquid ventilation in a rabbit model of acute lung injury / 대한마취과학회지

BACKGROUND: We examined the effects of varying inspiratory to expiratory (I : E) ratio on gas exchange and hemodynamics during high frequency partial liquid ventilation (HFPLV), a combination of high frequency ventilation (HFV) and partial liquid ventilation (PLV), in a rabbit model of acute lung injury. METHODS: Twelve rabbits treated with repeated saline lavage were divided into two groups. In the HFPL group (n = 6), 6 ml/kg of perfluorodecaline was administered through the endotracheal tube. Rabbits in this group and in the HFJ group (n = 6) were treated with high frequency jet ventilation (HFJV) at I : E ratios of 1 : 1, 1 : 2, and 1 : 3 for 15 minutes, and arterial blood gas, mixed venous blood gas and hemodynamic parameters were measured. RESULTS: We observed no significant respiratory and hemodynamic differences between the two groups. At an I : E ratio of 1 : 1, the PaO2 was significantly higher, and the shunt rate and PaCO2 were significantly lower in both groups, compared with I : E ratios of 1 : 2 and 1 : 3. Cardiac output at the 1 : 3 I : E ratio was significantly higher than at 1 : 1. CONCLUSIONS: These findings indicate that, in this model, a 1 : 1 I : E ratio was superior for oxygenation and ventilation than I : E ratios of 1 : 2 or 1 : 3, while having no detrimental effects on hemodynamics.

Comparison between Regional Cerebral Oxygen Saturation and Jugular Bulb Venous Oxygen Saturation in Patients Undergoing OPCAB Surgery / 대한마취과학회지

BACKGROUND: Hypoperfusion during manipulation of the heart in off-pump coronary artery bypass (OPCAB) surgery may lead to postoperative neurological complications. Therefore, it will be necessary to monitor cerebral function during OPCAB surgery. In this study, we compared regional cerebral oxygenation (rSO2) by near-infrared spectroscopy (NIRS) with jugular bulb venous oxygen saturation (SjvO2) and assessed whether rSO2 measured by NIRS could be an alternative method of SjvO2 during OPCAB surgery. METHODS: A total of 20 patients who underwent OPCAB surgery were studied. A fiberoptic catheter was placed in the right jugular bulb to measure SjvO2 while a cerebral oximeter based on NIRS, INVOS 5100B was used to monitor rSO2. Radial arterial and jugular bulb blood samples were drawn simultaneously from baseline every hour during operation. The values of rSO2 were compared with SjvO2 values. RESULTS: For all data points (n = 78) for all patients combined, rSO2 values were significantly correlated with SjvO2 values (r = 0.513, P < 0.0001). There were significant correlations between arterial carbon dioxide and values of SjvO2 (r = 0.393, P = 0.0002) and rSO2 (r = 0.432, P < 0.0001). CONCLUSIONS: We concluded that NIRS correlates with SjvO2 in this patient population. These findings suggest that near-infrared spectroscopy may be useful in assessing cerebral oxygenation during OPCAB surgery.

Ventilation impairment caused by upside-down connected unidirectional valves: A case report / 대한마취과학회지

We experienced a case of ventilation impairment resulted by the wrong-assembled unidirectional valves passed the automatic checkout of ventilator during general anesthesia. A 63-year-old man was scheduled for Ivor-Lewis operation due to esophageal cancer. After endotracheal intubation, ventilation impairment and abdominal distension were developed. No abnormal finding was found with bronchofiberoscopic examination. Suspecting anesthetic equipment failure, unidirectional valves were separated and they were proved to be connected upside-down.

Intravenous Patient-controlled Analgesia using Remifentanil after Cardiac Surgery / 대한마취과학회지

BACKGOUND: For rapid onset and predictable elimination half life, remifentanil may be suitable for patients undergoing cardiac surgery with unstable vital sign and decreased metabolism. We evaluated the efficacy, safety and proper dosage of intravenous patient-controlled analgesia (IV PCA) using remifentanil in patients undergoing cardiac surgery. METHODS: Forty-nine patients scheduled for cardiac surgery with sternotomy were randomly allocated to three groups. Group F had IV PCA using fentanyl with basal rate of 0.3microgram/kg/h, bolus of 0.5microgram/kg and lockout time of 15 min. Group L had remifentanil IV PCA with basal rate of 4microgram/kg/h, and group S with basal rate of 1microgram/kg/h. Both of group L and group S had setting of bolus of 0.5microgram/kg and lockout time of 5 min. In 12, 24 and 36 hours after surgery, vital sign, arterial blood gas analysis, visual analog pain scale (VAS), sedation score, and incidences of side effects were evaluated. RESULTS: The VAS score of group L was significantly low until 24 hours after surgery compared with other groups (P < 0.001). In group L, sedation score and PaCO2 in 12 hours after surgery were significantly high compared with other groups (P < 0.05), but no treatments were needed. CONCLUSIONS: Remifentanil IV PCA with basal rate of 4microgram/kg/h showed lower VAS score compared with small dosage of remifentanil and fentanyl with basal rate of 0.3microgram/kg/h. In the safety and proper dosage, further evaluations were needed.

A Clinical Study to Evaluate the Safety and Efficacy of a Patient-controlled Analgesia Pump in Post-surgical Patients / 대한마취과학회지

BACKGROUND: The disposable patient-controlled analgesia (PCA) devices are convenient for portability and management. An ideal PCA can be developed as an electronic device with various functions of safety and control. Recently, Accumate 1000(R) was developed as an electronic pump in Korea, and has passed the relevant laboratory criteria of safety and efficacy. We conducted a clinical study on the safety and efficacy when the device is applied to patients. METHODS: Fentanyl 1,500microgram, ketorolac 180 mg, and ondansetron 8 mg were used for PCA. Continuous infusion rate, bolus dose, and lockout time were set at 1 ml/h, 1 ml, and 15 min, respectively. Fifty patients were monitored for 48 h. The safety of Accumate 1000(R) was evaluated by backflow and siphonage, auto-clamp function, and lockout time intraoperatively. The efficacy was evaluated by the accuracy of bolus and total infused dose, and the satisfaction rates of patients and users. RESULTS: Backflow and siphonage did not occur, and the auto-clamp function was excellent. There was no bolus infusion during lockout time, and the bolus dose was infused accurately after lockout time. For the accuracy of the total infused dose, the mean and median value of performance error between the infused and target doses were -0.55%, and -0.29%, respectively. Noise, button sense, and convenience of cable were rated as satisfactory by 90%, 78%, and 84%, of patients respectively. CONCLUSIONS: The safety and efficacy of Accumate 1000(R) were established by clinical trial. We can provide patients with the more precise and optimal analgesia. The history of drug infusion can be used as research data.

Cerebral Ischemia Detected by the Bispectral Index during Cardiopulmonary Bypass: A case report / 대한마취과학회지

The bispectral index (BIS) has been developed as a measure for monitoring the hypnotic drug effect. EEG processing results in a BIS scale from 0 to 100, where 100 represents an awake and responsive patient, and the scale decreases when hypnotics are administered. Here we describe two patients in whom the BIS decreased to nearly 0 during cardiac surgery. Postoperatively both patients showed hypoxic brain injury. There are several possible causes for a decrease in the BIS during surgery, including deep anesthesia, hypothermia and cerebral ischemia. In the present cases, cerebral hypoperfusion was the likely cause. During cardiac surgery, hemodynamic changes such as acute hypotension and cardiac arrest can cause cerebral ischemia. Cerebral ischemia develops most commonly during cardiopulmonary bypass (CPB). Therefore, the BIS may be useful for detecting severe cerebral ischemia during CPB, although it has some limitations as a cerebral monitor.

Massive Carbon Dioxide Embolism during the Minimally Invasive Robot-assisted Cardiac Surgery: A case report / 대한마취과학회지

A 37-year-old female was scheduled for minimally invasive mitral valve replacement and Maze operation using the robotically controlled camera (AESOP 3000, Computermotion(R), USA). Thoracic incision and carbon dioxide insufflation was started. The end tidal carbon dioxide suddenly decreased with hypotension and an increase in central venous pressure to 70 mmHg. Then, cardiopulmonary bypass was started and large amount of gas was aspirated. Carbon dioxide embolism was suspected, carbon dioxide insufflation was discontinued. The aspiration of carbon dioxide embolus from cannulae for cardiopulmonary bypass confirmed our diagnosis. The gas flowed out from the peritoneal cavity following diaphragmatic incision, we suspected that the insufflating needle was placed into peritoneal cavity. The operation was completed uneventfully. No neurologic and cardiopulmonary sequelae were noted. We experienced a case of carbon dioxide embolism incidentally induced by carbon dioxide insufflation into closed intraperitoneal cavity.

The Changes of Skin Temperature on Hands and Feet During and after T3 Sympathicotomy for Palmar Hyperhidrosis

Unilateral thoracic sympathectomy in patients with palmar hyperhidrosis causes a skin temperature drop in the contralateral hand. A cross-inhibitory effect by the post-ganglionic neurons innervating hands is postulated as a mechanism of contralateral vasoconstriction. The purpose of our study was to evaluate whether this cross-inhibitory effect also occurs in the feet. Twenty patients scheduled for thoracoscopic sympathicotomy due to palmar hyperhidosis were studied. Right T3 sympathicotomy was performed first, followed by left T3 sympathicotomy. The thenar skin temperatures of both hands and feet were continuously monitored using a thermometer and recorded before induction of anesthesia, during the operation, 4 hr after and 1 week later. Following right T3 sympathicotomy, the skin temperature of the ipsilateral hand gradually increased, however the skin temperature of the contralateral hand gradually decreased. Immediately after bilateral sympathicotomy, the skin temperature differences between hands and feet increased, but these differences decreased 1 week later. Our results show that cross-inhibitory control may exist in feet as well as in the contralateral hand. Thus, the release of cross-inhibitory control following T3 sympathicotomy results in vasoconstriction and decrease of skin temperature on the contralateral hand and feet. One week later, however, the temperature balance on hands and feet recovers.

Kinking of the Advanced Venous Access Device during Insertion of the Superior Vena Cava Cannula and the Pulmonary Artery Catheter in the Minimally Invasive Robot-assisted Cardiac Surgery: A case report / 대한마취과학회지

A 59-year-old woman was scheduled for mitral valvuloplasty and Maze operation. As operation was planed to use the robotically controlled camera (Aesop 3000, Computermotion(r), USA) for the minimally invasive robot-assisted thoracotomy, a superior vena cava (SVC) cannula (Femoral arterial cannula [21 Fr], Medtronic(r), USA) was inserted in the right internal jugular vein. After insertion of the SVC cannula, a pulmonary artery (PA) catheter (Swan-Ganz CCOmbo V [7.5 Fr], Edwards(r), USA) was inserted through an advanced venous access device (AVA 3Xi [8.5 Fr], Edwards(r), USA) in the right subclavian vein. The tip of the PA catheter could not be advanced into SVC and blood was not regurgitated. In the chest AP X-ray, it was found that the advanced venous access device was kinked by the SVC cannula. So the advanced venous access device was withdrawn about 5 cm and the PA catheter was advanced easily to the destination.

The Comparison of Regional Cerebral Glucose Metabolism Using Positron Emission Tomography during Sevoflurane and Propofol Anesthesia in Human / 대한마취과학회지

BACKGROUND: Recent increases in use of sevoflurane have made active researches on its effects in the cerebral metabolism. However, no specific data on brain glucose metabolism has been reported from human study. We compared the brain glucose metabolism during sevoflurane anesthesia with that of propofol anesthesia using positron emission tomography (PET) in the same human volunteers. METHODS: PET scan was performed two times at intervals of one week in each eight volunteers. One scan was performed in sevoflurane anesthesia, and the other was performed in propofol anesthesia. Each was titrated to the point of unconsciousness. The scan was obtained by the 18fluorodeoxyglucose technique. Relative cerebral glucose metabolic rate (rCMRg) was assessed with statistical parametric mapping. RESULTS: The regions of decreased rCMRg during sevoflurane aneshesia were the visual cortex, posterior parietal association area, primary somatosensory area, and premotor area. During propofol anesthesia the decreased regions were the visual inferotemporal area and prefrontal association area in addition to those area of sevoflurane anesthesia. The increased regions were the partial prefrontal association area, basal ganglia, cingulate, olfactory-limbic cortex, midbrain, and pons during sevoflurane anesthesia, and the primary motor area, insula, thalamus, medulla along with those area of sevoflurane during propofol anesthesia. CONCLUSION: Propofol suppressed the rCMRg of neocortex area more than sevoflurane, and sevoflurane suppressed the rCMRg of paleocortex, telencephalon more than propofol when the unconsciousness level was achieved by anesthesia. Sevoflurane produces different effects on relative brain glucose metabolism with propofol.

The Effects of Dexmedetomidine on Hemodynamics and Plasma Catecholamine Concentrations during Coronary Artery Bypass Graft Surgery / 대한마취과학회지

BACKGROUND: Alpha-2 adrenergic agonists decrease the sympathetic tones of hemodynamic and endocrine responses to surgical stimuli. The goal of this study was to evaluate the hemodynamic and endocrinologic effects of intraoperatively administered dexmedetomidine, a highly selective alpha-2 adrenergic agonist, in patients undergoing coronary artery bypass graft surgery. METHODS: Fifty coronary artery bypass graft patients, in a double-blind, randomized manner, received a continuous infusion of normal saline placebo or dexmedetomidine, 10 ng/kg/min for 1 hr from 5 minutes after sternotomy. All patients received standardized anesthesia. Plasma catecholamine was measured at 5 minutes after sternotomy (T1), 30 minutes after drug infusion (T2), and 30 minutes after drug cessation (T3). Heart rate, blood pressure, pulmonary artery pressure and cardiac output were monitored. RESULTS: Compared with the placebo group, plasma norepinephrine concentrations decreased in the dexmedetomidine group Dexmedetomidine attenuated increased blood pressure on surgical stimuli and induced more hypotension. CONCLUSIONS: The intraoperative infusion of dexmedetomidine to patients undergoing coronary artery bypass graft surgery reduced sympathetic tone and attenuated hemodynamic responses to surgical stimuli.

Aortic/Radial Arterial Pressure Difference during Weaning from Cardiopulmonary Bypass in Open Heart Surgery Patients Anesthetized with Propofol-Alfentanil / 대한마취과학회지

BACKGROUND: Cardiovascular drugs are frequently used to assist myocardial function after discontinuation of cardiopulmonary bypass (CPB) in the open heart surgery (OHS) because of unstable hemodynamics. At this time we should always consider that the radial arterial pressure (RAP) may be lower than the aortic pressure (AP). In this study we evaluated the difference between AP and RAP in propofol-alfentanil anesthesia. METHODS: 28 patients undergoing elective OHS were randomly allocated into a midazolam-fentanyl (MA) group (n = 14) or a propofol-alfentanil (PA) group (n = 14). Anesthesia in the MF group consisted of midazolam and fentanyl with intermittent bolus injection, and anesthesia in the PA group consisted of propofol and alfentanil with continuous in fusion. RAP and AP in the two groups were recorded for 5 minutes after CPB discontinuation. RESULTS: No significant difference was founded between the two groups in age, weight, height, CPB time, aortic cross clamping (ACC) time, or temperature. There was a relatively high correlation between the difference of systolic AP-RAP and CPB time (r = 0.01), and ACC time (0.001). The systolic and mean blood pressure difference between the aorta and the radial artery in the MF group was significantly greater than in the PA group. CONCLUSIONS: This findings suggest that propofol-alfentanil anesthesia in OHS may be more helpful for hemodynamic management after CPB discontinuation than midazolam-fentanyl anesthesia.

Factors Affecting Post-sympathicotomy Pain in Palmar Hyperhidosis Patients / 대한마취과학회지

BACKGROUND: Discharge after day-surgery can be delayed for postoperative pain in a video-assisted thoracic sympathicotomy (VATS). However, there seems to be no research about postoperative pain after a VATS. We examined the characteristics of patients and operative factors, and compared the severity of postoperative pain according to different anesthetics. METHODS: We examined the age, sex, obesity index, and pain tolerance in 194 VATS patients of ASA physical status 1 or 2. The patients were randomly divided into two groups each with 97 patients. Group P was anesthetized with propofol, and group E with enflurane. We measured the visual analog scale (VAS) score at 5 minute, 2 hours, and 6 hours after arrival at the recovery room. RESULTS: There was no difference in the VAS score according to age, sex, obesity index, or pain tolerance. The VAS score at coughing was significantly higher than at rest. The VAS score in group P was higher than group E, but there was no significant difference. The patients who had a complication of a pneumothorax had a significantly higher VAS score. CONCLUSIONS: Postoperative pain seems to be aggravated by remaining air within the thorax after VATS.

Anesthetic Management for Ascending Aorta Replacement Using Deep Hypothermic Circulatory Arrest in a Heart Transplanted Patient / 대한마취과학회지

We present a case of a patient who had undergone human allograft cardiac transplantation 5 months before ascending aorta replacement. A pseudoaneurysm at the anastomotic site of ascending aorta with periaortic hematoma compressing the superior vena cava (SVC) had been revealed by chest CT, and after the median sternotomy, paraaortic abscess was revealed as the cause of this patient's SVC syndrome. The ascending aorta replacement was performed under deep hypothermic circulatory arrest. The anesthetic management of this patient included the use of a sterile technique, slow cautious induction, and the maintenance of adequate intravascular volume.

The Comparison of the Concentration of Free Hemoglobin in Packed RBC, Intraoperative Salvaged Blood and CPB Residual Blood during Cardiac Surgery / 대한마취과학회지

BACKGROUND: Intraoperative autotransfusion or residual blood in a cardiopulmonary bypass (CPB) circuit has been used to reduce the need for an homologous blood transfusion during cardiac surgery. However, it may contain some free hemoglobin released from damaged cells. The load of blood containing free hemoglobin may cause renal dysfunction. We measured the amount of free hemoglobin in banked blood, cell saver blood and CPB blood to evaluate what is the least hemolytic blood transfused in cardiac surgery. METHODS: This study was performed in 20 patients undergoing cardiac surgery. In each patient, the banked blood, intraoperative salvaged blood with a cell saver and CPB residual blood were sampled at the end of the operation. The concentration of free hemoglobin, hemoglobin and platelet counts were measured in these blood samples and percent of hemolysis was calculated (%hemolysis = [free hemoglobin] / [free hemoglobin hemoglobin]) RESULTS: In salvaged blood with a cell saver, CPB residual blood and banked blood, hemoglobin concentrations were 20.1+/-2.7 g/dl, 8.0+/-1.1 g/dl, and 22.2+/-2.7 g/dl, respectively. Free hemoglobin concentrations were 336.6+/-239.5 mg/dl, 49.2+/-26.8 mg/dl, and 279.5+/-167.5 mg/dl respectively. Platelet counts were 26.1+/-22.2X10(3)/mm3, 116.8+/-56.5X10(3)/mm3, and 94.9+/-43.6X10(3)/mm3 respectively. % Hemolysis were 1.6+/-1.1%, 0.6+/-0.4%, and 1.2+/-0.7% respectively. In the comparison between the salvaged blood with a cell saver and CPB residual blood, free hemoglobin concentration, % hemolysis, and platelet counts had positive correlations (r = 0.8, 0.7, and 0.6). CONCLUSIONS: In twenty cardiac surgeries, CPB residual blood had a lower free hemoglobin level than the other two blood groups. The platelet counts in CPB residual blood were higher than those in cell saver blood but did not differ from those in banked blood. Therefore, CPB residual blood was the least hemolytic blood among the three blood groups when a transfusion was performed in cardiac surgery.

Measurement of Ventilation-Perfusion Ratio Using Multiple Inert Gas Elimination Technique in the Endotoxin-Induced Septic Rabbit / 대한마취과학회지

BACKGROUND: Endotoxin is a complex lipopolysaccharide molecule situated within the outer membrane of Gram-negative bacteria. Sepsis and acute respiratory failure (ARDS) can be induced by endotoxin. In order to introduce and develop the experimental model of ARDS in sepsis, we induced sepsis with the endotoxin and investigated the change of respiratory pathophysiology during sepsis using a multiple inert gas elimination technique (MIGET). METHODS: Ten New Zealand white rabbits were anesthetized and ventilated with a Harvard apparatus. In 5 rabbits, 2 mg/kg of lipopolysaccaride from E. coli was infused intravenously for 30 min (Toxin group). At 1, 2, 3, and 4 hours after endotoxin infusion, arterial blood gas, and hemodynamic profiles were checked. To perform the MIGET, six inert gases (SF6, krypton, desflurane, enflurane, diethyl ether, acetone) of widely varying solubility were infused peripherally and the excretion and retention data was determined from measurements of inert gas tensions in pulmonary arterial, systemic arterial blood samples and mixd expiratory gas sampling of pre and post septicemia using gas chromatography. We transformed and analysed the data into a V/Q distribution curve to find out the change of V/Q distribution curve. After the experiments, the animals were dissected and the lungs were extracted for wet/dry weight ratio (WW/DW) and microscopic examination. RESULTS: In the Toxin group, the pulmonary arterial pressures were increased and arterial oxygen tensions were decreased after the endotoxin infusion. The lung WW/DW were increased and inflammatory findings were seen in microscopic examination. In the MIGET, shunt, deadspace and log SDQ were increased in the toxin group, though there were wide V/Q distributions in the control group. CONCLUSIONS: We developed a successful endotoxin induced septic animal model, V/Q distribution curve and data using MIGET. The accomplishment of the experiment will not only allow us to better understand pulmonary pathophysiology of endotoxin induced sepsis using MIGET, but it will also contribute to other pulmonary physiology experiments associated with sepsis.