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Background: For patients in the intensive care unit (ICU) or under monitored anesthetic care (MAC), the precise monitoring of sedation depth facilitates the optimization of dosage and prevents adverse complications from under­ or over­sedation. For this purpose, conventional subjective sedation scales, such as the Observer's Assessment of Alertness/Sedation (OAA/S) or the Ramsay scale, have been widely utilized. Current procedures frequently disturb the patient's comfort and compromise the already well­established sedation. Therefore, reliable objective sedation scales that do not cause disturbances would be beneficial. We aimed to determine whether spectral entropy can be used as a sedation monitor as well as determine its ability to discriminate all levels of propofol­induced sedation during gradual increments of propofol dosage. Methods: In 25 healthy volunteers undergoing general anesthesia, the values of response entropy (RE) and state entropy (SE) corresponding to each OAA/S (5 to 1) were determined. The scores were then analyzed during each 0.5 mcg/ml­ incremental increase of a propofol dose. Results: We observed a reduction of both RE and SE values that correlated with the OAA/S (correlation coefficient of 0.819 in RE­OAA/S and 0.753 in SE­OAA/S). The RE and SE values corresponding to awake (OAA/S score 5), light sedation (OAA/S 3-4) and deep sedation (OAA/S 1-2) displayed differences (P < 0.05). Conclusions: The results indicate that spectral entropy can be utilized as a reliable objective monitor to determine the depth of propofol­induced sedation. (Korean J Anesthesiol 2012; 62: 234­239)

† Background: Though caudal block is a relative simple technique, it has not been widely used in adults because of a high failure rate. We assumed that any tests to quantify the changes of sympathetic tone in the affected areas would be excellent indicators of successful block. We tested the usefulness of two candidates (pulse oximetry plethysmographic waveform amplitude measured at 5 th toe and calf minus 5 th toe skin temperature gradient) as indicators of successful caudal block. Methods: In 45 adult patients undergoing anal surgery with caudal block, these two variables were simultaneously measured at 2-min intervals for 20 min. A two-fold increase in the plethysmographic waveform amplitude from baseline and skin temperature gradient of 0 o C were predefined as test criteria of successful block. Results: While the sensitivity, specificity, positive predictive value, and negative predictive value of the skin temperature gradient test were 45.9%, 100%, 100%, and 9.1%, those of the plethysmographic waveform test were 86.5%, 100%, 100%, and 28.6%. The plethysmographic waveform test showed a significantly higher discriminative capacity than the skin temperature gradient test (94.9% vs. 48.7%, P < 0.05) Conclusions: Unlike the skin temperature gradient test, the plethysmographic waveform test showed a considerably high validity in detecting successful block. Considering its simple and real time monitoring potentials together with a high failure rate of caudal block in adults, we cautiously recommend it as a supplemental diagnostic tool to predict successful block, especially when verbal communication with patient is difficult. (Korean J Anesthesiol 2007; 53: S 19∼25)

Premature infants with respiratory distress syndrome may have clinically significant shunting through a patent ductus arteriosus (PDA). Left-to-right shunting through the PDA may lead to left ventricular volume overload and pulmonary edema. We present a case of perioperative management for severe respiratory distress syndrome in a premature infant who underwent surgical closure of PDA. Under general anesthesia, the infant was successfully managed by inhaled nitric oxide, high frequency oscillation ventilation with intermittent mandatory ventilation despite intermittent hypoxia. The operation was performed safely in the neonatal intensive care unit.

Background: It has been suspected that laparoscopic surgery exacerbates hypothermia to a greater extent than open surgery. Thus, this study was designed to compare the intraoperative thermoregulatory profiles of three different operative techniques: open surgery, low pressure (LP: 8 mmHg) or conventional pressure (CP: 13 mmHg) laparoscopic surgery. Methods: Forty five patients who were scheduled for radical hysterectomy were allocated to three groups, 15 in each group: group O (open surgery), group LP and group CP. Anesthesia was maintained with 2.5% sevoflurane. Intraoperative core temperature and forearm minus fingertip skin temperature gradients were measured at 15-min intervals during the first three hours. Vasoconstriction threshold was defined by the esophageal temperature at which the skin temperature gradient equalled . Results: All groups were comparable in terms of the characteristics of patients and preoperative body temperatures. Core temperatures and forearm minus fingertip skin temperature gradients were not significantly different among the three groups at all measurements. Thermoregulatory vasoconstrictions were observed in 6 of group O and 6 of laparoscopic surgical patients (4 patients from group LP and 2 patients from group CP). These 12 patients were divided into open (n = 6) and laparoscopic (n = 6) surgery group. There were no significant difference between the groups with regard to the vasoconstriction threshold and threshold time. Conclusions: Laparoscopic procedures with conventional insufflation pressure have similar profiles in terms of intraoperative thermoregulation, when compared to open surgery. Lowering insufflation pressure to 8 mmHg can not reduce the risk of intraoperative hypothermia.

We present a case of an anesthetic gas leak through the valve of the Selectatec back bar during a surgical procedure. The Selectatec Vaporizing System is a quick-change system consisting of anesthetic vaporizers of the 'Tec models' of the Ohmeda machine that are seated on a compatibility manifold block located on the back bar of the anesthetic machine. In order to prevent a leak and a failure of vapor delivery, the 'Tec models series' can only be turned 'on' when the locking lever is turned to the 'lock' position. However in this case, the control knob was rotated despite the back bar locking mechanism not being engaged, and a gas leak developed through the unlocked valves in Selectatec back bar. The Penlon Sigma Delta Anesthetic Vaporizer (sevoflurane) in a Datex-Ohmeda Aestiva/5 anesthesia machine can be turned 'on' when the locking lever is maintained at the 'unlock' position.

Background: Ropivacaine is a long acting, amide-type local anesthetic with a chemical structure similar to that of bupivacaine. In this study we investigated the efficacies of 18 ml of 0.5% bupivacaine, and of 0.5% and 0.75% ropivacaine to provide caudal anesthesia. Methods: Sixty ASA physical status 1 or 2 patients undergoing hemorrhoidectomy were randomly allocated to 3 parallel treatment groups to receive either 18 ml of 0.5% bupivacaine, or 0.5% or 0.75% ropivacaine. Caudal anesthesia was performed using the loss of resistance method via sacral hiatus. Soft touch testing around the anal sphincter muscle, the pin prick method at the S3 dermatome, onset time of loss of anal sphincter reflex, and sensory block were checked following local anesthetic injection. Duration of sensory block was assessed at 30 minute intervals through out block duration. Quality of muscle relaxation was assessed by the surgeon at the end of each operation. Blood pressures were measured and the incidences of nausea, vomiting and dizziness were recorded. Results: Significant differences were observed between the 0.5% ropivacaine and 0.75% ropivacaine groups (P

A 14-month-old female patient was admitted for the laparoscopic excision of a complicated urachal cyst. General anesthesia was induced with thiopental and rocuronium and maintained with sevoflurane and the intermittent administration of vecuronium. During the insufflation of her intra-abdominal pressure was maintained below 12 cm to avoid excessive hypercarbia. Thirty minutes after insufflation initiation, end tidal increased to 74 mmHg at a peak inspiratory airway pressure of 24 cm. Laparoscopic excision of the urachal cyst was performed within 2 hours without a further change in end tidal , blood pressure, heart rate, or saturation. Before extubation, saturation by pulse oxymetry was 99% and end tidal was 45-50 mmHg. The patient was discharged without any problem 5 days after the operation. We report on this clinical experience and include a brief review of the literature.

Background: Diabetes mellitus is the most common endocrinopathy encountered in the perioperative period and has long been assumed to increase perioperative risk. However, when diabetes mellitus was segregated from old age and the complications of it, it was questioned that diabetes mellitus itself increased perioperative risk. In this study, we investigated the influence of hyperglycemia on the length of postoperative hospital stay. Methods: We studied 100 patients undergone intra-abdominal operations with general anesthesia. These patients were divided into the hyperglycemic group (n = 20) with postoperative blood glucose level higher than 10 mM and the non-hyperglycemic group (n = 80) with glucose level lower than 10 mM and we investigated the length of postoperative hospital stay, serum electrolyte, serum chemistry, arterial blood gas values, and base excess by unmeasured anions. We also divided these patients into the diabetic patients group (n = 15) and the non-diabetic patients group (n = 85) and compared the same variables. Results: The length of postoperative hospital stay was significantly prolonged in the hyperglycemic group ( days) compared with the non-hyperglycemic group ( days), and the cumulative postoperative hospital stay curves based on Kaplan-Meier method also showed significant difference between the two groups. When we compared the length of postoperative hospital stay between the diabetic and the non-diabetic patients, there was no significant difference. Conclusions: This study demonstrated that hyperglycemia prolonged the length of postoperative hospital stay. This finding suggests that the patient´s glucose level should be monitored and controlled within an adequate range perioperatively.

Background: Diabetes mellitus is the most common endocrinopathy encountered in the perioperative period. It is a disease of glucose dysregulation and carbohydrate intolerance frequently associated with acute and long-term systemic consequences, which may significantly impact morbidity and mortality. This study was performed to evaluate the effects of diabetes on perioperative patients’ status. Methods: Thirty adults patients, 15 control and 15 diabetic patients, who underwent upper abdominal surgery with general anesthesia were included in this study. We investigated blood glucose levels, arterial blood gas, blood chemistry values, and calculated alveolar- arterial oxygen tension differences. Statistical analyses were performed using the Fisher's exact test, unpaired t-test, paired t-test, and repeated measure ANOVA. Data are expressed as mean SD. Results: The blood glucose levels were significantly higher in the diabetic group than the control group during operation. The postoperative calcium and albumin concentrations were significantly lower in the diabetic patients than the control patients. The alveolar-arterial oxygen tension differences were significantly increased in the diabetic group compared with the control group during operation. Conclusions: This study demonstrated that the blood glucose levels were significantly increased in the diabetic patients compared with the control patients during operation. This finding suggests that blood glucose levels should be monitored and controlled within an adequate range in diabetic patients perioperatively.

Background: When large volume of intravenous saline are administered to correct extracellular fluid deficits, metabolic acidosis can result. Two theories have been proposed to explain metabolic acidosis, dilutional acidosis and hyperchloremic acidosis. This study was performed to evaluate the possible explanations for metabolic acidosis resulting from the infusion of large amounts of normal saline. Methods: Thirty two adult patients who underwent upper abdominal surgery with general anesthesia were included in this study. All patients were allocated randomly to receive either normal saline (NS group, n = 16) or Hartmann's solution (HS group, n = 16) during anesthesia. We monitored arterial blood gas, electrolyte, and hematocrit values during the perioperative period. We also calculated the estimated postoperative HC0 concentrations based on dilutional acidosis or hyperchloremic acidosis and compared these with the measured HC0 concentrations. Statistical analyses were performed using the Fisher's exact test, unpaired t-test, paired t-test, and repeated measure ANOVA. Data are expressed as means SD. Results: The infusion of normal saline, but not of Hartmann's solution, caused metabolic acidosis with hyperchloremia. The estimated postoperative HC0 concentration based on dilutional acidosis was almost the same as the measured HC0 concentration. The estimated postoperative HC0 concentration based on hyperchloremic acidosis was significantly lower than based on dilutional acidosis and the measured HC0 concentration. Conclusions: Infusion of large amounts of normal saline during anesthesia produced metabolic acidosis, which was not observed after the administration of Hartmann's solution. The appropriate term to describe this phenomenon is suggested to be dilutional acidosis.

Background: Portable glucometers are often utilized at the patient's bedside in the ICU or operating room for frequent measurements of the blood glucose concentration. Many of these devices are based on a glucose oxidase method that may be influenced by . The aim of this study was to evaluate the influence of a high of arterial blood on measured glucose values compared with venous blood. Methods: Forty adult patients who underwent surgery with general anesthesia were included in this study. Each patient had a cannula inserted into the radial artery and a central venous catheter through the right internal jugular vein. Two hours after the induction of anesthesia, we drew arterial and venous blood and measured the blood glucose concentration using both a bedside glucometer based on a glucose oxidase method and a laboratory glucometer based on a hexokinase method. We also measured blood gas, electrolyte, and hematocrit values. Statistical analyses were performed with repeated measure ANOVA, multiple linear regression, and Bland-Altman's analysis. Data is expressed as mean . SD. Results: The arterial blood glucose concentration measured by the glucose oxidase method (119.5 25.0 mg/dl) was significantly lower than the venous blood (133.5 24.8 mg/dl) and hexokinase method (134.2 27.1 mg/dl). There was no significant difference between the venous blood glucose concentration by the glucose oxidase method and hexokinase method. When we used the correction formula: corrected glucose value = arterial glucose value by glucose oxidase method + 0.1053 - 5.414, the bias improved from - 14.6 mg/dl to 1.0 mg/dl. Conclusions: The blood glucose concentration measured by the glucose oxidase method is more accurate in venous blood than oxygenated arterial blood. When we measure the blood glucose level using the glucose oxidase method, we should consider the influence of high oxygen tension.

Problems related to agitation in the ICU patients include cardiorespiratory instability, ina bility to cooperate with nursing care, failure to maintain op timal positioning in bed, dis- ruption of life sustaining tubes and catheters, and injuries to patients and hospital person- nel. Thus, the ability to provide safe, controllable, and reversible sedation can be important in the care of critically ill patients. Midazolam is a water soluble imidazobenzodiazepine with a rapid onset of ac tion and short elimination half life compared with diazepam or lorazepam. We evaluated the use of midazolam by continuous infusion for prolonged sedation of critically ill adult patients. The results were as follows ; 1) Midazolam infusion effectively controlled severe agitation in all patients. 2) No episodes of cardiovascular depression due to midazolam occur red during the study period. 3) In one patient, tolerance was developed 6 days after infusion. 4) Mean time to alertness was 2.23 hours. 5) In a renal failure patient, there was no significant prolongation of time to alertness. These results suggest that midazolam infusion provides safe, controllable, and reversible sedation in the care of critically ill patients.

Intrapulmonary percussive ventilation(IPV), developed by Forrest M. Bird, M.D., delivers high flow mini-bursts of air along with bronchodilator to the lung at a rate of more than 200 times per minute and has the theoretical potential for aiding in expectoration of secretions through internal percussion. To evaluate effects of IPV on respiratory therapy, we compared IPV with conventional chest physical therapy in patients with excess or retained pulmonary secretions. The results are follows. 1) There were no significant differences among the experimental group with respect to blood pressure, heart rate and respiratory rate. 2) Arterial oxygen tension was significantly increased after IPV. 3) ICU stay was slightly shortened in the experimental group as compared with that in the control group. However, there was no statistical significance. These results indicate that IPV may be effective in respiratory care of patients with excess or retained airway secretions.