Koichi Tsuzaki

Anesthesia‐related mortality and morbidity over a 5‐year period in 2,363,038 patients in Japan

Background:  Statistical data of mortality and morbidity related to anesthesia have not been reported in Japan since World War II. The need to comprehensively examine the events of cardiac arrest as well as mortality prompted the first national study in Japan.

Segmental bioelectrical impedance analysis improves the prediction for extracellular water volume changes during abdominal surgery.

OBJECTIVE To determine whether the segmental multifrequency bioelectrical impedance analysis may improve the prediction for intraoperative changes in extracellular water volume (deltaECW) compared with whole body multifrequency bioelectrical impedance analysis in abdominal surgical patients. DESIGN Prospective, consecutive sample. SETTING Surgical operative patients in a university-affiliated city hospital. PATIENTS Thirty patients who underwent elective gastrointestinal surgery. INTERVENTIONS Multifrequency bioelectrical impedance analysis was conducted preoperatively (before the induction of anesthesia) and postoperatively (after recovery from anesthesia). Resistance values fitted at zero frequency (R0) in the whole body and in each body segment (arm, trunk, and leg) were determined by performing nonlinear curve-fitting and subsequent extrapolation. DeltaECW values were estimated from the whole body resistance between wrist and ankle using two different prediction formulas. In segmental multifrequency bioelectrical impedance analysis, however, ECW was obtained as the sum of each body segment (arms, trunk, and legs) using the equation newly derived from the cell suspension theory. DeltaECW estimated from both measurements were compared with net fluid balances during surgery. MEASUREMENTS AND MAIN RESULTS R0 in whole body and all body segments significantly decreased after surgery (p < .0001). The most striking decrease in post/preoperative ratios was found in the R0 in the trunk. The post/preoperative ratio of the R0 value in the trunk was significantly lower than the post/preoperative ratio of the R0 value in the leg (p = .0007). DeltaECW from segmental multifrequency bioelectrical impedance analysis was similar to net fluid balance (r2 = .80, bias = -0.03 L), whereas whole body multifrequency bioelectrical impedance analysis resulted in considerable underestimations of deltaECW (r2 = .50, .51, bias = 0.95, 0.53 L). CONCLUSIONS The difference in the prediction of deltaECW between whole body and segmental multifrequency bioelectrical impedance analysis may be explained by the significant decrease in the resistance of the trunk, which contributed only minimally to the whole body resistance. Segmental multifrequency bioelectrical impedance analysis provides a better approach to predict ECW changes in critically ill patients with nonuniform fluid distribution.

An Apnea Monitor Using a Rapid-Response Hygrometer

ObjectiveThe aim of this study was to detect cyclic changes in the relative humidity (RH) occurring with spontaneous respiration using a rapid-response hygrometer, and to evaluate its potential applicability as an apnea monitor in nonintubated subjects.MethodsRespiratory monitoring using a rapid-response hygrometer was performed in spontaneously breathing, nonintubated subjects. Changes in RH during spontaneous breathing were measured in adult volunteers, breathing room air and nonintubated infants who underwent cardiac catheterization under intravenous anesthesia. The detection of apnea by the hygrometer was assessed in the adult patients during the induction of anesthesia and those undergoing minor gynecologic surgery under epidural anesthesia. The hygrometric sensor was positioned in front of the nostril; a simultaneous recording of CO2 was obtained from nasal cannulas by a sidestream capnograph. Each waveform was collected and acquired by a PC-based computer, and data were analyzed off-line.ResultsThe hygrometer showed a rapid response to the cyclic changes in RH during spontaneous respiration and could identify respiratory phases of tachypnea as high as 60 breaths per minute in infants. RH rapidly increased to 80% with a plateau on expiration and decreased to 40% on inspiration. These phasic changes, consisting of three distinct phases, expiratory upstroke, plateau and inspiratory downslope, preceded the corresponding capnographic changes by nearly two seconds. Expiratory increase in RH appeared to be influenced by the respiratory flow rate as well as the response time of the equipment. As respiration was depressed due to airway obstruction, the magnitude of RH gradually decreased and then disappeared at the time of apnea.ConclusionsThe hygrometer could detect cyclic changes in RH during spontaneous respiration. Apnea was immediately detected by the decreases in the magnitude of RH. The results demonstrate the potential usefulness of a rapid-response hygrometer for monitoring respiratory rate and early detection of apnea.

Anesthesia-related mortality and morbidity in Japan (1999).

1 Department of Anesthesiology, Teikyo University School of Medicine, 2-11-1 Kaga, Itabashi-ku, Tokyo 173-8605, Japan 2 Department of Anesthesiology and Critical Care Medicine, Jichi Medical School, Tochigi, Japan 3 Department of Anesthesiology and Resuscitology, Okayama University, Graduate School of Medicine and Dentistry, Okayama, Japan 4 Department of Anesthesiology and Critical Care Medicine, Graduate School of Medical Sciences, Kyushu University, Fukuoka, Japan 5 Department of Anesthesiology, Kyorin University School of Medicine, Mitaka, Tokyo, Japan 6 Department of Anesthesiology, School of Medicine, Keio University, Tokyo, Japan 7 Department of Anesthesiology and Intensive Care Medicine, Kanazawa University, Graduate School of Medical Science, Kanazawa, Japan 8 Sapporo Ichijyo Clinic, Sapporo, Japan 9 Department of Anesthesiology and Critical Care Medicine, Gifu University School of Medicine, Gifu, Japan

High-frequency ventilation in neonates

STUDY OBJECTIVE To provide a brief review of the current status of high-frequency ventilation in neonatal respiratory care. DATA IDENTIFICATION Publications appearing between 1980 and 1990 were identified by computer searches using the National Library of Medicines data base, MEDLINE, and by searching bibliographies of identified articles. STUDY SELECTION Studies related to physiologic background and clinical reports of neonatal application were selected individually. DATA EXTRACTION Data concerning the physiologic basis, clinical effectiveness and complications, and latest results of a multicenter randomized trial were evaluated and used to develop a current concept. RESULTS OF DATA SYNTHESIS In early clinical tests of high-frequency ventilation, it was considered beneficial that airway pressure lower than that used in conventional mechanical ventilation might reduce the frequency of pulmonary barotrauma. When high-frequency ventilation was applied to infants with respiratory distress syndrome, the development of chronic pulmonary complications also was expected to decrease. Although several reports supported this hypothesis, a recent controlled trial involving multiple clinical centers did not find significant improvement in the group treated with high-frequency ventilation. Rather, they recognized the frequent occurrence of complications associated with high-frequency ventilation and suggested the prior use of conventional ventilation. However, a possible defect of this study design requires further studies to elucidate the source of these conflicting results. CONCLUSIONS As a mode of mechanical ventilation, high-frequency ventilation is useful for maintaining ventilation in patients with air leak syndrome or bronchopulmonary fistula or during bronchoscopic examination. But in general, its role as an alternative to conventional ventilation still remains controversial.

Strategies for blood transfusion in critical bleeding

The Subcommittee on Surveillance of AnaesthesiaRelated Critical Incidents of the JSA analysed the data. Contributing factors include far greater rate and amount of bleeding than anticipated (Fig. 2), delay in decision to start blood transfusion and to order additional blood products, hesitation to use ABO-compatible blood including group O Blood without cross-matching, delayed transportation of the blood products from the blood banks, and lack of man power. In patients with critical bleeding, blood loss was >12 l ⁄60 kg(body weight) in 35AE2% of the patients, and the maximal estimated bleeding rate was >240 ml ⁄60 kg(body weight) ⁄min in 44AE9% of the patients. Despite critical bleeding and shortage of blood products due to delayed transportation of the blood products, cross-matching test was waived in 13AE4% of the patients, and ABO-compatible blood products including group O blood was used only in 1AE3% of the patients. It suggests that using uncross-matched blood might be a major concern in the physicians in Japan even in the

Emergency laparotomy in uncontrolled thyrotoxic patient with preoperative fulminant hepatic failure

Acute stress of anesthesia and surgery can precipitate thyroid crrsis postoperatively in uncontrolled thyrotoxic patients. Preexisted liver dysfunction may also be aggravated in the postoperative period. V ncontrolled thyrotoxic patient developed fulminant hepatic failure, and during the course she suffered acute panperitonitis due to upper gastrointestinal tract perforation and underwent emergency laparotomy. We describe our perioperative management of this patient.

Perioperative Factors Associated with Chronic Central Pain after the Resection of Intramedullary Spinal Cord Tumor

Objective: Some patients experience severe chronic pain after intramedullary spinal cord tumor (IMSCT) resection, but the underlying mechanisms have yet to be fully elucidated. We aimed to investigate perioperative factors associated with chronic pain after IMSCT resection. Materials and Methods: We analyzed data from a postal survey and the medical records of patients who had undergone IMSCT resection in our institution between 2000 and 2008. Chronic pain was assessed using the Neuropathic Pain Symptom Inventory score, and its associations with factors related to tumor pathology, patient demographics, neurological findings, surgery, anesthesia, and perioperative management were determined. Results: Seventy-eight consecutive patients (55 men and 23 women; age 17 to 79 y) were included in the statistical analysis of the present study. In univariate analyses, sex, body mass index, preoperative tumor-related pain, preoperative nonsteroidal anti-inflammatory drugs, intraoperative hypotension, postoperative corticosteroids, and decrease in Japanese Orthopaedic Association (JOA) scores were found to be associated with postsurgical chronic central pain. Logistic regression analysis identified 3 significant factors: a decline in JOA scores compared with preoperative values (odds ratio [OR], 3.33; 95% confidence interval [CI], 1.18-9.42; P=0.023), intraoperative hypotension (OR, 3.01; 95% CI, 1.02-8.97; P=0.047), and postoperative corticosteroids (OR, 3.21; 95% CI, 1.02-10.09; P=0.046). Discussion: Decline in JOA score, intraoperative hypotension, and postoperative corticosteroids are independently associated with postsurgical chronic central pain. Intraoperative hypotension and the use of postoperative corticosteroids can be avoided or modified during perioperative management. As results from animal studies have indicated that the administration of corticosteroids may intensify chronic pain, further studies in larger cohorts are required to definitively determine the effect of corticosteroids on postsurgical central pain.

Titration of propofol infusion using processed electroencephalogram during combined general and spinal anesthesia

PurposeTo determine the necessary mean infusion rate of propofol during combined nitrous oxide (N2O) and propofol spinal anesthesia by using the processed electroencephalogram (pEEG).MethodsTwelve elective gynecological patients were monitored by a Dräger pEEG monitor under N2O and propofol spinal anesthesia. To make it easier to detect an inadequate depth of anesthesia, muscle relaxants were not given and the patients breathed spontaneously through a laryngeal mask airway. Manual step-down infusion of propofol was employed to provide intraoperative hypnosis. Propofol infusion was titrated to maintain cardiorespiratory parameters within 20% of baseline and the 90th percentile of the spectral edge frequency (SEF 90) of the pEEG between 10 and 13.5 Hz.ResultsThe mean (SD) induction dose of propofol was 2.9 (0.4) mg·kg−1. The mean (SD) maintenance infusion rate was 4.2 (0.5) mg·kg−1·h−1. The mean (SD) time from the end of propofol infusion to the opening of the patients eyes was 5.4 (2.0) min. No gross movements or intraoperative awareness was recognized. The mean (SD) SEF 90 during the maintenance of anesthesia was 12.2 (1.5) Hz, which increased significantly to 16.2 (1.9) Hz at 1 min before the patients opened their eyes in reponse to verbal commands.ConclusionTitration of propofol infusion using SEF during combined general and spinal anesthesia provided a rapid recovery without any clinical signs of inadequate anesthesia.

Effect of low-dose infusion of prostaglandin E1 on vecuronium-induced neuromuscular blockade

The effect of low-dose (20 ng·kg−1·min−1) infusion of prostaglandin E1 (PGE1) on vecuronium-induced neuromuscular blockade was studied. The study population consisted of 24 elderly patients (65–75 years old) and 24 younger adult patients (25–56 years old). They were randomly assigned to the control and PGE1 groups. The steady-state dose requirement (SSDR) of vecuronium was derived from ondemand infusion of the drug which produced a stable twitch height of 20% of its baseline reading, and recovery time after steady-state infusion was defined as the time for recovery from twitch height from 25% to 75%. The patients in the PGE1 group received an infusion of PGE1 20 ng·kg−1·min−1, while those in the control group received an infusion of normal saline. The SSDR (23.2±9.1 and 34.2±5.9 μg·kg−1. hr−1, respectively;P=0.02) was significantly less and the recovery time (35.0±9.5 and 19.9±4.2 min, respectively;P=0.01) was significantly longer in the elderly than in the younger patients. However, low-dose infusion of PGE1 significantly increased the SSDR (23.2±9.1 to 37.4±3.7 μg· kg−1·hr−1;P=0.01) and shortened the recovery time (35.0±9.5 to 23.5±4.0 min;P=0.02) in elderly patients. We concluded that low-dose infusion of PGE1 is effective in preventing the prolonged action of vecuronium in elderly patients.