Usefulness of oxygen reserve index (ORi™), a new parameter of oxygenation reserve potential, for rapid sequence induction of general anesthesia.

The oxygen reserve index (ORi™) is a new parameter for monitoring oxygen reserve noninvasively. The aim of this study was to examine the usefulness of ORi for rapid sequence induction (RSI). Twenty adult patients who were scheduled for surgical procedures under general anesthesia were enrolled. After attaching a sensor capable of measuring ORi, oxygen (6 L/min) and fentanyl (2 µg/kg) were administered. After 3 min, propofol 2 mg/kg and rocuronium 1 mg/kg were administered without ventilation. Regardless of changes in ORi, tracheal intubation was performed either 2 min after administration of propofol or when percutaneous oxygen saturation (SpO2) reached 98%. Ventilation was then provided with oxygen at 6 L/min, and trends in ORi and SpO2 during RSI were observed. Data from 16 of the 20 patients were analyzed. Before oxygen administration, the median SpO2 was 98% [interquartile range (IQR) 97-98] and ORi was 0.00 in all patients. At 3 min after starting oxygen administration, the median SpO2 was 100% (IQR 100-100) and the median ORi was 0.50 (IQR 0.42-0.57). There was an SpO2 decline of 1% or more from the peak value after propofol administration in 13 patients, and 32.5 s (IQR 18.8-51.3) before the SpO2 decrease, ORi began to decline in 10 of the 13 (77%) patients. The ORi trends enable us to predict oxygenation reduction approximately 30 s before SpO2 starts to decline. By monitoring ORi, the incidence related to hypoxemia during RSI could be reduced.

Population pharmacokinetics of intravenous acetaminophen in Japanese patients undergoing elective surgery.

INTRODUCTION: Intravenous (i.v.) acetaminophen is administered during surgery for postoperative analgesia. However, little information is available on the pharmacokinetics of i.v. acetaminophen in Japanese patients undergoing surgery under general anesthesia. METHODS: The study was approved by the Institutional Review Board and registered at UMIN-CTR (UMIN000013418). Patients scheduled to undergo elective surgery under general anesthesia were enrolled after obtaining written informed consent. During surgery, 1 g of i.v. acetaminophen was administered over 15, 60, or 120 min. Acetaminophen concentrations (15 or 16 samples per case) were measured at time points from 0-480 min after the start of administration (liquid chromatography-mass spectrometry/tandem mass spectrometry; limit of quantitation 0.1 µg/mL). The predictive performance of three published pharmacokinetic models was evaluated. Population pharmacokinetics were also analyzed using a nonlinear mixed-effect model based on the NONMEM program. RESULTS: Data from 12 patients who underwent endoscopic or lower limb procedures were analyzed (male/female = 7/5, median age 55 years, weight 63 kg). Anesthesia was maintained with remifentanil and propofol or sevoflurane. The pharmacokinetic model of i.v. acetaminophen reported by Würthwein et al. worked well. Using 185 datapoints, the pharmacokinetics of i.v. acetaminophen were described by a two-compartment model with weight as a covariate but not age, sex, or creatinine clearance. The median prediction error and median absolute prediction error of the final model were -1 and 10%, respectively. CONCLUSION: A population pharmacokinetic model of i.v. acetaminophen in Japanese patients was constructed, with performance within acceptable ranges.

Effects of acute gamma irradiation on Folsomia candida (Collembola) in a standard test.

An understanding of the effects of ionizing radiation on non-human biota is required by the International Commission on Radiological Protection for the radiological protection of the environment. We examined dose-effect relationships for gamma radiation on survival, growth, and reproduction in the soil invertebrate Folsomia candida (Collembola) in a standard laboratory test. F. candida were acutely irradiated at increasing doses of gamma radiation, and subsequent survival, growth in body length, and number of neonates produced by irradiated specimens were examined. The 50% lethal dose was at 1356 Gy, and the 10% and 50% effective doses (ED10 and ED50) for growth were at 32 and 144 Gy, respectively. The ED10 and ED50 values for reproduction were at 7.1 and 21.9 Gy, respectively. These data establish important baselines for the radiological protection of terrestrial ecosystems based on scientific principles.

Surgery for active, culture negative endocarditis.

Culture negative infective endocarditis (CNE) poses very difficult problems during treatment. In this study it was found that of 132 surgically treated patients with infective endocarditis, causative organism was not identified in 46 (34.8 %). Pre- and perioperative conditions and clinical results of these patients were evaluated. CNE remained very frequent even in these years, and it did not decrease with time. Antibiotic treatment prior to microbiological examinations was commonly observed (nearly 90% orally, and 70% intravenously). In average, it took more than 2 months to establish the diagnosis of CNE after the onset, and both aortic and mitral valves were affected frequently (19.0 %). New York Heart Association functional class IV was observed significantly more commonly (61.9%) than culture positive patients. Frequencies of prosthetic valve endocarditis (12.2%), periannular abscess (36.3%), and embolism (21.4%) were similar. Infection was fairly controllable before surgery in 43.9% of CNE patients and in-hospital mortality rate was 14.3%, both of which were comparable to those of all culture positive patients. However, recurrence rate was relatively higher (10.0%). The conditions and outcomes of CNE were comparable to Staphylococcal endocarditis in some aspects, and were relatively worse than overall culture positive endocarditis.

[Surgical treatment of active infective endocarditis: analysis of 20 years' experience].

OBJECTIVES: Changes in perioperative condition and outcomes of surgically treated patients with active infective endocarditis were evaluated during the last 20 years. METHODS: Between 1983 and 2002, 132 patients with active infective endocarditis underwent surgery at Saitama Medical School. Changes in frequency, pathogens, clinical features, surgical results, and perioperative treatment were compared between four periods of 5 years. RESULTS: The percentage of surgery for infective endocarditis remained almost the same among all cardiovascular procedures. Staphylococcal infective endocarditis increased significantly (p < 0.01), and prosthetic valve infective endocarditis and periannular abscess became more common. Surgery tended to be performed in severely ill patients significantly more frequently (p < 0.01). If all patients were included, hospital mortality did not decrease significantly, at 1.7% in stable patients, but 50% in critically ill patients. Intensive care unit stay became relatively longer. Recurrent infection was observed significantly more frequently in critically ill patients and in patients with prosthetic valve infective endocarditis. Patients were referred for surgery following diagnosis and underwent surgery at increasingly more appropriate timing. However, the diagnosis of infective endocarditis took 1.5 months to establish regardless of the patient's condition or the clinical outcome. Moreover, antibiotics were administered orally in around 90% and intravenously in nearly 70% of the patients without microbiological tests, and negative cultures remained very frequent. CONCLUSIONS: Critically ill patients underwent surgery increasingly more frequently, and surgical outcomes remained unsatisfactory over the last 20 years. Early diagnosis and avoidance of premature antibiotic therapy may be important for future improvement.