Effective concentration of remifentanil for successful i-gel insertion during remimazolam induction / 대한마취과학회지

Background@#Remifentanil can be used as adjuvants during remimazolam induction without neuromuscular blockade. We evaluated the 95% effective concentration (EC) of remifentanil effect-site concentration (Ce) for the successful insertion of an i-gel using the biased-coin up-and-down method in adult patients during remimazolam induction. @*Methods@#Forty 19–65 year-old patients scheduled to undergo surgery using i-gel were enrolled. Anesthesia was induced using remimazolam infusion (12 mg/kg/h). Simultaneously, remifentanil was infused at a predetermined Ce. After 5 min of anesthesia induction, the i-gel was inserted. The 95% EC (EC95) of remifentanil in each patient was determined using a biased-coin up-and-down method based on a successful insertion in a preceding patient. The step size of remifentanil Ce was 0.4 ng/ml. If the insertion failed, remifentanil Ce was increased in the next patient. Following successful insertions, the corresponding concentration decreased in subsequent patients with a probability of 1/19 or was maintained with a probability of 18/19. The time from remimazolam infusion initiation to a bispectral index (BIS) < 60 (time to BIS60) and hemodynamic variables were measured and recorded. @*Results@#The EC95 (95% CI) of Ce was 2.07 (1.94, 2.87) ng/ml. The overall time to BIS60 was 154.0 ± 39.9 s. No patient experienced significant hypotension or bradycardia during remimazolam induction. @*Conclusions@#The EC95 of remifentanil Ce was 2.07 (1.94, 2.87) ng/ml for successful i-gel insertion during remimazolam induction at 12 mg/kg/h without hemodynamic instability in adult patients. Future studies should measure remifentanil Ce in elderly patients or using remimazolam at various infusion doses.

Prediction of early postoperative desaturation in extreme older patients after spinal anesthesia for femur fracture surgery: a retrospective analysis / 대한마취과학회지

BACKGROUND@#Postoperative desaturation in older individuals is rarely addressed in the literature. The objective of this retrospective study was to investigate whether a preoperative spirometric test and arterial blood gas analysis (ABGA) might predict postoperative desaturation after spinal anesthesia in extreme older patients.@*METHODS@#The medical records of 399 patients (age ≥ 80 yrs) who were administered spinal anesthesia for a femur neck fracture surgery were retrospectively reviewed. Early postoperative desaturation was defined as a reduction of oxygen saturation (SpO₂) below 90% within 3 days of surgery, despite O₂ supply via a nasal prong. Binary logistic regression analysis was used to identify predictors of early postoperative desaturation.@*RESULTS@#The incidence of postoperative desaturation was 12.5%. Major morbidity rate was significantly higher in the desaturation group (n = 50) than that in the non-desaturation group (n = 349) (14% vs. 3.2%, P = 0.001) with more frequent postoperative stays in the intensive care unit (22% vs. 12%, P = 0.004). In a binary logistic regression analysis, preoperative ratio of arterial oxygen partial pressure to fractional inspired oxygen (PaO₂/FiO₂ ratio) (OR, 0.972; 95% CI 0.952–0.993; P = 0.010) and history of cardiovascular disease (OR, 2.127; 95% CI 1.004–4.507; P = 0.049) predicted postoperative desaturation.@*CONCLUSIONS@#Preoperative PaO₂/FiO₂ ratio, but not preoperative spirometry, was predictive of the postoperative desaturation in older patients after being administered spinal anesthesia for femur fracture surgery. Based on our results, preoperative ABGA may be helpful in predicting early postoperative desaturation in these patients.

Prediction of early postoperative desaturation in extreme older patients after spinal anesthesia for femur fracture surgery: a retrospective analysis / 대한마취과학회지

BACKGROUND: Postoperative desaturation in older individuals is rarely addressed in the literature. The objective of this retrospective study was to investigate whether a preoperative spirometric test and arterial blood gas analysis (ABGA) might predict postoperative desaturation after spinal anesthesia in extreme older patients.METHODS: The medical records of 399 patients (age ≥ 80 yrs) who were administered spinal anesthesia for a femur neck fracture surgery were retrospectively reviewed. Early postoperative desaturation was defined as a reduction of oxygen saturation (SpO₂) below 90% within 3 days of surgery, despite O₂ supply via a nasal prong. Binary logistic regression analysis was used to identify predictors of early postoperative desaturation.RESULTS: The incidence of postoperative desaturation was 12.5%. Major morbidity rate was significantly higher in the desaturation group (n = 50) than that in the non-desaturation group (n = 349) (14% vs. 3.2%, P = 0.001) with more frequent postoperative stays in the intensive care unit (22% vs. 12%, P = 0.004). In a binary logistic regression analysis, preoperative ratio of arterial oxygen partial pressure to fractional inspired oxygen (PaO₂/FiO₂ ratio) (OR, 0.972; 95% CI 0.952–0.993; P = 0.010) and history of cardiovascular disease (OR, 2.127; 95% CI 1.004–4.507; P = 0.049) predicted postoperative desaturation.CONCLUSIONS: Preoperative PaO₂/FiO₂ ratio, but not preoperative spirometry, was predictive of the postoperative desaturation in older patients after being administered spinal anesthesia for femur fracture surgery. Based on our results, preoperative ABGA may be helpful in predicting early postoperative desaturation in these patients.

Sedation Strategies for Procedures Outside the Operating Room

With the rapid development of diagnostic and therapeutic procedures performed outside the operating room (OR), the need for appropriate sedation care has emerged in importance to ensure the safety and comfort of patients and clinicians. The preparation and administration of sedatives and sedation care outside the OR require careful attention, proper monitoring systems, and clinically useful sedation guidelines. This literature review addresses proper monitoring and selection of sedatives for diagnostic and interventional procedures outside the OR. As the depth of sedation increases, respiratory depression and cardiovascular suppression become serious, necessitating careful surveillance using appropriate monitoring equipment.

Acid/base alterations during major abdominal surgery: 6% hydroxyethyl starch infusion versus 5% albumin / 대한마취과학회지

BACKGROUND: To compare the effects of intraoperative infusions of balanced electrolyte solution (BES)-based hydroxyethyl starch (HES) and saline-based albumin on metabolic acidosis and acid/base changes during major abdominal surgery conducted using Stewart’s approach. METHODS: Forty patients, aged 20-65 years, undergoing major abdominal surgery, were randomly assigned to the HES group (n = 20; received 500 ml of BES-based 6% HES 130/0.4) or the albumin group (n = 20; received 500 ml of normal saline-based 5% albumin). Acid-base parameters were measured and calculated using results obtained from arterial blood samples taken after anesthesia induction (T1), 2 hours after surgery commencement (T2), immediately after surgery (T3), and 1 hour after arriving at a postanesthetic care unit (T4). RESULTS: Arterial pH in the HES group was significantly higher than that in the albumin group at T3 (7.40 ± 0.04 vs. 7.38 ± 0.04, P = 0.043), and pH values exhibited significant intergroup difference over time (P = 0.002). Arterial pH was significantly lower at T3 and T4 in the HES group and at T2, T3, and T4 in the albumin group than at T1. Apparent strong ion difference (SIDa) was significantly lower at T2, T3, and T4 than at T1 in both groups. Total plasma weak nonvolatile acid (ATOT) was significantly lower in the HES group than in the albumin group at T2, T3 and T4 and exhibited a significant intergroup difference over time (P < 0.001). CONCLUSIONS: BES-based 6% HES infusion was associated with lower arterial pH values at the end of surgery than saline-based 5% albumin infusion, but neither colloid caused clinically significant metabolic acidosis (defined as an arterial pH < 7.35).

What is the proper ventilation strategy during laparoscopic surgery? / 대한마취과학회지

The main stream of intraabdominal surgery has changed from laparotomy to laparoscopy, but anesthetic care for laparoscopic surgery is challenging for clinicians, because pneumoperitoneum might aggravate respiratory mechanics and arterial oxygenation. The authors reviewed the literature regarding ventilation strategies that reduce deleterious pulmonary physiologic changes during pneumoperitoneum for laparoscopic surgery under general anesthesia and make appropriate recommendations.

Changes in cerebral oxygen saturation and early postoperative cognitive function after laparoscopic gastrectomy: a comparison with conventional open surgery / 대한마취과학회지

BACKGROUND: Laparoscopic gastrectomy requires a reverse-Trendelenburg position and prolonged pneumoperitoneum and it could cause significant changes in cerebral homeostasis and lead to cognitive dysfunction. We compared changes in regional cerebral oxygen saturation (rSO2), early postoperative cognitive function and hemodynamic variables in patients undergoing laparoscopic gastrectomy with those patients that underwent conventional open gastrectomy. METHODS: Sixty patients were enrolled in this study and the patients were distributed to receive either laparoscopic gastrectomy (laparoscopy group, n = 30) or open conventional gastrectomy (open group, n = 30). rSO2, end-tidal carbon dioxide tension, hemodynamic variables and arterial blood gas analysis were monitored during the operation. The enrolled patients underwent the mini-mental state examination 1 day before and 5 days after surgery for evaluation of early postoperative cognitive function. RESULTS: Compared to baseline value, rSO2 and end-tidal carbon dioxide tension increased significantly in the laparoscopy group after pneumoperitoneum, whereas no change was observed in the open group. No patient experienced cerebral oxygen desaturation or postoperative cognitive dysfunction. Changes in mean arterial pressure over time were significantly different between the groups (P < 0.001). CONCLUSIONS: Both laparoscopic and open gastrectomy did not induce cerebral desaturation or early postoperative cognitive dysfunction in patients under desflurane anesthesia. However, rSO2 values during surgery favoured laparoscopic surgery, which was possibly related to increased cerebral blood flow due to increased carbon dioxide tension and the effect of a reverse Trendelenburg position.

Predicted EC50 and EC95 of Remifentanil for Smooth Removal of a Laryngeal Mask Airway Under Propofol Anesthesia

PURPOSE: The purpose of this study was to determine the effect-site concentration (Ce) of remifentanil in 50% of patients (EC50) and 95% of patients (EC95) for smooth laryngeal mask airway (LMA) removal in adults under propofol and remifentanil anesthesia. MATERIALS AND METHODS: Twenty-five patients of ASA physical status I-II and ages 18-60 years who were to undergo minor gynecological or orthopedic surgery were assessed in this study. Anesthesia was induced and maintained with propofol and remifentanil target-controlled infusion (TCI). Remifentanil was maintained at a predetermined Ce during the emergence period. The modified Dixon's up-and-down method was used to determine the remifentanil concentration, starting from 1.0 ng/mL (step size of 0.2 ng/mL). Successful removal of the LMA was regarded as absence of coughing/gagging, clenched teeth, gross purposeful movements, breath holding, laryngospasm, or desaturation to SpO2<90%. RESULTS: The mean+/-SD Ce of remifentanil for smooth LMA removal after propofol anesthesia was 0.83+/-0.16 ng/mL. Using isotonic regression with a bootstrapping approach, the estimated EC50 and EC95 of remifentanil Ce were 0.91 ng/mL [95% confidence interval (CI), 0.77-1.07 ng/mL] and 1.35 ng/mL (95% CI, 1.16-1.38 ng/mL), respectively. CONCLUSION: Our results showed that remifentanil TCI at an established Ce is a reliable technique for achieving safe and smooth emergence without coughing, laryngospasm, or other airway reflexes.

The effect of warmed inspired gases on body temperature during arthroscopic shoulder surgery under general anesthesia / 대한마취과학회지

BACKGROUND: Perioperative hypothermia can develop easily during shoulder arthroscopy, because cold irrigation can directly influence core body temperature. The authors investigated whether active warming and humidification of inspired gases reduces falls in core body temperature and allows redistribution of body heat in patients undergoing arthroscopic shoulder surgery under general anesthesia. METHODS: Patients scheduled for arthroscopic shoulder surgery were randomly assigned to receive either room temperature inspired gases using a conventional respiratory circuit (the control group, n = 20) or inspired gases humidified and heated using a humidified and electrically heated circuit (HHC) (the heated group, n = 20). RESULTS: Core temperatures were significantly lower in both groups from 30 min after anesthesia induction, but were significantly higher in the heated group than in the control group from 75 to 120 min after anesthesia induction. CONCLUSIONS: In this study the use of a humidified and electrically heated circuit did not prevent core temperature falling during arthroscopic shoulder surgery, but it was found to decrease reductions in core temperature from 75 min after anesthesia induction.

An anesthetic experience of a patient with paraneoplastic encephalitis: A case report

Paraneoplastic encephalitis associated with an ovarian teratoma has been related to the development of antibodies to specific heteromers of the N-methyl-D-aspartate receptor (NMDAR). The disorder, known as anti-NMDAR encephalitis, is characterized by psychiatric symptoms, seizures, mood and behavioral changes as well as involuntary movement. Since the NMDAR is the target of many anesthetic drugs, the presence of anti-NMDAR antibodies might influence the requirements of anesthetics or their effects. We report the presentation and anesthetic experience of a young patient with anti-NMDAR encephalitis undergoing surgical excision of two ovarian teratomas, and we also review the relevant literature.

Comparison of the effects of sevoflurane and propofol on core body temperature during laparoscopic abdominal surgery / 대한마취과학회지

BACKGROUND: A decrease in core body temperature caused by heat distribution depends on the anesthetic agent used. The purpose of this study is to investigate the effects of sevoflurane and propofol on core temperature during laparoscopic major abdominal surgery requiring pneumoperitoneum of more than 90 min. METHODS: Fifty adult patients undergoing laparoscopic major abdominal surgery were randomly assigned to either a sevoflurane group (n = 25) or a propofol group (n = 25). In the sevoflurane group, anesthesia was induced with propofol 2 mg/kg, remifentanil 1.0 microg/kg, and maintained with 0.8-2.0 vol% sevoflurane and 0.1-0.2 microg/kg/min remifentanil. In the propofol group, anesthesia was induced with the effect-site concentration of propofol of 5.0 microg/ml and remifentanil 4 ng/ml, and maintained with the effect-site concentration of propofol of 2-3.5 microg/ml and remifentanil 3-5 ng/ml. Core body temperature was measured with an esophageal stethoscope with a temperature sensor after the start of the pneumoperitoneum (baseline) and at 15-min intervals until completion of surgery. RESULTS: During the study period, core temperature was comparable between the two groups. When compared with baseline values, core temperatures in both groups were significantly decreased 45 min after pneumoperitoneum. CONCLUSIONS: This study demonstrated that in patients undergoing prolonged laparoscopic surgery, a decrease in core body temperature during sevoflurane-remifentanil anesthesia was not different than propofol-remifentanil anesthesia, and the incidence of hypothermia of the two groups did not differ.

The preventative effect of ramosetron on postoperative nausea and vomiting after total thyroidectomy / 대한마취과학회지

BACKGROUND: Postoperative nausea and vomiting (PONV) frequently develops in patients undergoing thyroidectomy, and propofol-based total intravenous anesthesia (TIVA) has been reported to reduce the incidence of PONV. The present study was undertaken to compare the effects of ramosetron on PONV in women following total thyroidectomy under TIVA. METHODS: One hundred and thirty women scheduled for thyroidectomy were allocated to either a control group (n = 65) or a ramosetron group (n = 65). Propofol in combination with remifentanil was used for TIVA in all patients. 2 ml of either intravenous saline (control group) or 0.3 mg of ramosetron (ramosetron group) were administered at the end of the surgery. Fentanyl-based patient-controlled analgesia was implemented for 48 h after surgery in all patients. The incidences and severities of PONV, pain scores, administrations of rescue antiemetics, and the side effects of the antiemetics were documented during the first 48 h after surgery. RESULTS: The incidences of complete response (no PONV, no rescue) in the control and ramosetron groups were 71% and 88%, respectively, during the first 6 h (P = 0.029), 85% and 94% during the next 6 to 24 h period (P = 0.155), and 97% and 95% during the last 24 to 48 h period (P = 1.00). During the first 6 h, the severity of nausea and the use of rescue antiemetic medication were significantly lower in the ramosetron group. CONCLUSIONS: Ramosetron was found to be effective at reducing the incidence and severity of postoperative nausea in women that underwent total thyroidectomy with propofol-based TIVA, especially during the first 6 hours postoperatively.

Anesthetic experience in a pediatric patient with mastocytosis / 대한마취과학회지

No abstract available.

The effect of heating insufflation gas on acid-base alterations and core temperature during laparoscopic major abdominal surgery / 대한마취과학회지

BACKGROUND: Carbon dioxide (CO2) has different biophysical properties under different thermal conditions, which may affect its rate of absorption in the blood and the related adverse events. The present study was aimed to investigate the effects of heating of CO2 on acid-base balance using Stewart's physiochemical approach, and body temperature during laparoscopy. METHODS: Thirty adult patients undergoing laparoscopic major abdominal surgery were randomized to receive either room temperature CO2 (control group, n = 15) or heated CO2 (heated group, n = 15). The acid-base parameters were measured 10 min after the induction of anesthesia (T1), 40 min after pneumoperitoneum (T2), at the end of surgery (T3) and 1 h after surgery (T4). Body temperature was measured at 15-min intervals until the end of the surgery. RESULTS: There were no significant differences in pH, PaCO2, the apparent strong ion difference, the strong ion gap, bicarbonate ion, or lactate between two groups throughout the whole investigation period. At T2, pH was decreased whereas PaCO2 was increased in both groups compared with T1 but these changes were not significantly different. Body temperatures in the heated group were significantly higher than those in the control group from 30 to 90 min after pneumoperitoneum. CONCLUSIONS: The heating of insufflating CO2 did not affect changes in the acid-base status and PaCO2 in patients undergoing laparoscopic abdominal surgery when the ventilator was set to maintain constant end-tidal CO2. However, the heated CO2 reduced the decrease in the core body temperature 30 min after the pneumoperitoneum.

A case of Churg-Strauss syndrome that underwent endoscopic sinus surgery under total intravenous anesthesia: A case report

Churg-Strauss syndrome is also known as allergic granulomatosis, and it is a rare systemic vasculitis that may affect multiple organ systems, and particularly the lungs.A 42-year-old woman with Churg-Strauss syndrome underwent endoscopic sinus surgery under total intravenous anesthesia with propofol and remifentanil. Anesthesia was performed uneventfully, but there were several issues of concern that evolved regarding the perioperative management of a patient with this syndrome.

Combination of nitrous oxide and lidocaine to prevent withdrawal after rocuronium in children / 대한마취과학회지

BACKGROUND: Pain at the site of rocuronium injection is a common side-effect in pediatric patients. This prospective, randomized, double-blind study evaluated the efficacy of a combination of nitrous oxide and lidocaine pretreatment on withdrawal response during rocuronium injection in children. METHODS: Sixty six pediatric patients, ages 5 to 12 years, were randomly assigned to two groups. The oxygen group received 100% oxygen, and the nitrous oxide group received 50% N2O in oxygen over 2 min. After anesthesia was induced with 2.5% thiopental sodium 5 mg/kg and manual occlusion of the forearm was performed, 1% lidocaine 1 mg/kg was injected over 15 sec. After the occlusion was released, 0.1% rocuronium 0.6 mg/kg was injected over 5 sec. Patient response to rocuronium injection was graded using a 4-point scale. RESULTS: Overall incidence of withdrawal movements was significantly lower in the nitrous oxide group (1 patients; 3.1%) than in the oxygen group (8 patients; 25.8%) (P = 0.013). No patient in the nitrous oxide group displayed arm or generalized movement (grade 3 or 4) associated with rocuronium injection. CONCLUSIONS: This study demonstrated that a combination of inhaled 50% N2O in O2 and 1 mg/kg lidocaine pretreatment significantly reduced the incidence of rocuronium-induced withdrawal movements in pediatric patients compared with lidocaine pretreatment alone.

Interrupted aortic arch diagnosed with loss of femoral pulse in a patient undergoing patent ductus arteriosus ligation: A case report / 대한마취과학회지

A 12-year-old boy with ventricular septal defect and patent ductus arteriosus was presented to the operating room. Upon clamping the patent ductus arteriosus, the femoral arterial pressure curve was lost; however, it returned upon unclamping. Upon further dissection, an interrupted aortic arch was found between the left subclavian artery and patent ductus arteriosus. The surgery was discontinued for further evaluation.

Acid-base changes during liver transplantation using Stewart's physicochemical approach: living related donor vs. cadaveric donor

BACKGROUND: Intraoperative acid-base imbalance frequently occurs during liver transplantation (LT). The purpose of this study was to compare the acid-base changes between cadaveric whole LT and a LT from a living relative using a strong ion approach. METHODS: Twenty-four patients undergoing LT were allocated to a group receiving a LT from a brain dead donor (BD group, n = 12) or a LT from a living, related donor (LD group, n = 12) according to the surgical technique required. Acid-base parameters such as PaCO2, pH, base excess, and serum concentrations of bicarbonate, albumin, lactate, phosphate, and other electrolytes were measured at 30 min after skin incision (T1), 30 min after reperfusion (T2), and 1 h after the arrival at the intensive care unit (T3). The apparent strong ion difference (SIDa), the effective strong ion difference (SIDe), and the strong ion gap (SIG) were calculated using the Stewart equation. RESULTS: There were no significant differences in pH, PaCO2, base excess, SIDa, and SIG between the two groups throughout the entire period of investigation. pH was decreased from T1 to T2, and increased significantly from T2 to T3 in both groups. The serum concentration of lactate was significantly increased from T1 to T2 and T3 in both groups without any intergroup differences. The strong ion gap was significantly increased from T1 to T2 only in the BD group. CONCLUSIONS: During LT from both cadaveric and living related donors, there is a biphasic acid-base change that is characterized by an initial metabolic acidosis and then a metabolic alkalosis, with no significant intergroup differences in acid-base variables.

Anesthetic management for a patient with Eisenmenger syndrome undergoing dacryocystorhinostomy: A case report

Eisenmenger syndrome is defined as pulmonary hypertension at or close to systemic values, with an intracardiac or aortopulmonary communication resulting a bidirectional or right-to-left shunt.Patients with Eisenmenger syndrome require a close monitoring while undergoing non-cardiac surgery because these patients are very vulnerable to alteration in hemodynamics induced by anesthetics or surgery.Therefore we report the successful management of a patient with Eisenmenger syndrome undergoing a dacryocystorhinostomy under desflurane and ketamine based general anesthesia.

Atrial flutter associated with high pressure pneumoperitoneum during laparoscopic gastrectomy: A case report

Pneumoperitoneum associated with carbon dioxide (CO2) insufflation may induce alterations in electrocardiographic variables, which may produce severe atrial and ventricular arrhythmias.We now present a case in which atrial flutter developed after CO2 insufflation in a patient undergoing laparoscopic subtotal gastrectomy.Although the ECG change was reversed after desufflation, one should keep in mind the increased propensity to atrial and ventricular arrhythmias during laparoscopy with high intra-abdominal pressure.