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.

Palonosetron might not attenuate spinal anesthesia-induced hypotension during orthopedic surgery

BACKGROUND: 5-Hydroxytryptamine3 (5-HT3) receptor antagonists have been reported to attenuate spinal anesthesia-induced hemodynamic changes. This study was conducted to determine whether the second generation 5-HT3, antagonist palonosetron attenuates hypotension and bradycardia during spinal anesthesia. METHODS: Sixty adult patients scheduled for lower limb surgery were enrolled in this study. Patients were randomly assigned to receive either normal saline (Control group, N = 30) or palonosetron (0.075 mg, i.v.) (Palonosetron group, N = 30) prior to spinal anesthesia. Hemodynamic variables were recorded during anesthesia. RESULTS: The mean blood pressure (MBP) were 89.2 ± 11.4 mmHg in the control group and 87.6 ± 12.1 mmHg in the palonosetron group at 10 min after intrathecal injection (P = 0.609). The median blocked levels of the control group and the palonosetron group were T10 (interquartile range, 9-10) and T10 (8-10) at 20 min after intrathecal injection (P = 0.939). Requirements for ephedrine, phenylephrine, and atropine were similar (P = 0.652, 0.533 and 0.417, respectively). The incidences of hypotension (40% vs. 41%) and bradycardia (7% vs. 17%) were comparable (P = 0.562, P = 0.198, respectively) between the control and the palonosetron group. There were no significances in the changes of systolic blood pressure, diastolic blood pressure, MBP and heart rate by the group (P = 0.632, 0.287, 0.556, 0.733, respectively). CONCLUSIONS: Intravenous palonosetron (0.075 mg) prior to spinal anesthesia might not attenuate spinal anesthesia-induced hypotension during low level of neuroaxial block for lower limb surgery.

Anesthetic management of a patient with pulmonary arteriovenous malformation under total intravenous anesthesia : A case report / 대한마취과학회지

A 23-year-old woman with pulmonary arteriovenous malformation was scheduled for open reduction and internal fixation due to her mandible fracture. Total intravenous anesthesia using propofol and remifentanil was selected as the anesthetic method in order to avoid the inhibition of hypoxic pulmonary vasoconstriction and the exacerbation of intrapulmonary shunting. After the standard monitoring devices were applied, anesthesia was then induced and maintained with a target controlled infusion of propofol and remifentanil in the range of 2.5-3.0 microg/ml and 2-3 ng/ml, respectively. Anesthesia was performed uneventfully and the patient was discharged without complication.

The Effect of SCD Response Compression System on Coagulation and Fibrinolysis using Thromboelastography in Patients Undergoing Gastrectomy; a Comparison with Elastic Stocking / 대한마취과학회지

BACKGROUND: Among various measures to prevent deep venous thrombosis (DVT) in surgical patients, intermittent pneumatic compression of the legs is known to be effective without increasing the risk of bleeding. In this study, the coagulation/ fibrinolysis profile in patients undergoing gastrectomy with SCD Response Compression System, which detects individual venous refill time, was compared to that with elastic stocking using thromboelastography (TEG). METHODS: Fifty-eight ASA class I-II patients undergoing gastrectomy were randomized into two groups. Patients in ES group (n = 29) were treated with elastic stocking and patients in SCD group (n = 29) were treated with SCD Response Compression System. TEG analysis and traditional coagulation tests were performed on arrival in the operating room, after surgery in the postanesthetic care unit and on the morning of postoperative day 1. RESULTS: There was no significant difference in laboratory data between the two groups. Laboratory data at all time points were within normal limit in all patients. There was no significant difference in TEG data between the two groups. No evidence of a postoperative clinical coagulopathy (DVT or pulmonary embolism) was observed on routine history and physical examinations in any patient during hospitalization. CONCLUSIONS: The effectiveness of SCD Response Compression System in patients undergoing major abdominal surgery on coagulation/fibrinolysis system was similar to that of elastic stocking during perioperative period.

Effect of Intra-cuff 4% Lidocaine on the Dosage of Nitroglycerine Required to Maintain Hemodynamic Stability before and after Extubation in Patients with Hypertension

BACKGROUND: Elevated blood pressures during emergence from general anesthesia in patients with hypertension often result in undesirable complications such as myocardial ischemia, intracranial hemorrhages. The aim of this study was to assess the effect of intracuff 4% lidocaine on the dosage of nitroglycerine required to maintain the stable blood pressure during peri-extubation period in patients with hypertension. METHODS: Forty-nine patients scheduled for elective surgery were randomly allocated to group 1 and 2. We filled endotracheal tube's cuff with normal saline for group 1 and with 4% lidocaine for group 2. Blood pressures and heart rates were recorded before operation, during emergence, and after extubation. Nitroglycerine infusion was adjusted to maintain systolic blood pressure below 150 mmHg. Total infused dosages of nitroglycerine were recorded during operation and after stop of inhalational anesthetics for comparison of both groups' hemodynamic stability. RESULTS: Mean infused volume (microg/kg/min) of nitroglycerine during peri-extubation period was less in the group 2 than group 1. CONCLUSIONS: Intra-cuff 4% lidocaine in patients with hypertension during emergence from general anesthesia reduces the nitroglycerine dosage required to maintain hemodynamic stability.