S Ogawa

Nihon University, Edo, Tōkyō, Japan

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Publications (45)58.71 Total impact

  • [Show abstract] [Hide abstract]
    ABSTRACT: BACKGROUND: Flumazenil is generally administered to antagonise the sedative effect of midazolam. However, although flumazenil completely antagonises the sedative effect of midazolam, a few effects remain unantagonised. Hence, it is unclear whether flumazenil restores the attenuation of the arterial-cardiac baroreflex (i.e. arterial-heart rate reflex) induced by midazolam. We investigated the antagonistic effect of flumazenil administered after midazolam on cardiac baroreflex, to reveal whether complete recovery from midazolam-induced sedation by flumazenil administration is accompanied by restoration of midazolam's attenuating effects on the cardiac baroreflex. METHOD: Twelve healthy male subjects received midazolam followed by flumazenil until complete recovery from midazolam sedation. Before and during midazolam sedation, and after flumazenil administration, cardiac baroreflex function was assessed by sequence analysis and transfer function analysis between spontaneous oscillations in systolic arterial pressure and R-R interval. RESULTS: During midazolam sedation, defined by an Observer's Assessment of Alertness/Sedation scale score of 3, BIS value decreased significantly. Simultaneously, the baroreflex indices of the two analyses decreased significantly compared with baseline, suggesting attenuated cardiac baroreflex function. With complete recovery from midazolam sedation by flumazenil, indicated by an Observer's Assessment of Alertness/Sedation scale score of 5, BIS values returned to the baseline level. Simultaneously, cardiac baroreflex indices also returned to baseline levels. CONCLUSION: The present results suggest that complete recovery from midazolam sedation by flumazenil is accompanied by restoration of the attenuated cardiac baroreflex function induced by midazolam.
    Acta Anaesthesiologica Scandinavica 12/2012; 57(4). DOI:10.1111/aas.12035 · 2.31 Impact Factor
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    ABSTRACT: Increasing age is associated with a longer duration of action of neuromuscular block. The aim of this study was to determine the influence of ageing on the recovery of the post-tetanic count (PTC) from rocuronium-induced neuromuscular block. Twenty-two younger (20-60 years) and 22 older (> 70 years) patients were enrolled in this study. After induction of anaesthesia with fentanyl and propofol, all patients initially received 1 mg/kg rocuronium and neuromuscular block were evaluated by contractions of the adductor pollicis muscle to ulnar nerve train-of-four stimulation using an acceleromyograph. Subsequently, intense rocuronium-induced block was determined every 6 min using the PTC during 1.0-1.5% sevoflurane and remifentanil anaesthesia. When the first response to the PTC stimulus was detected, 0.2 mg/kg rocuronium was additionally administered, and again, spontaneous recovery of neuromuscular function was monitored until the first response to the PTC reappeared. Median values (range) of the times from the administration of 1 mg/kg and 0.2 mg/kg rocuronium until recovery of the first detectable PTC were significantly longer in the older [51.0 (27-100) min, P < 0.0001 and 30.0 (12-66) min, P = 0.0036, respectively] than the younger patients [31.5 (21-45) min and 18.0 (12-36) min, respectively]. The times from rocuronium injection to reappearance of the first response to PTC stimulation are approximately twofold longer and more variable in older than younger patients. Hence, the dosing interval of rocuronium should be adjusted using neuromuscular monitoring when maintaining intense neuromuscular block, especially in older patients.
    Acta Anaesthesiologica Scandinavica 02/2012; 56(2):236-9. DOI:10.1111/j.1399-6576.2011.02605.x · 2.31 Impact Factor
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    ABSTRACT: The aim of this study was to evaluate the correlation between cardiac output (CO) and reversibility of rocuronium-induced moderate neuromuscular block with sugammadex in elderly patients. Fifty elderly (≥ 65 years) patients were enrolled in this study. During 1.0-1.5% end-tidal sevoflurane and remifentanil anaesthesia, contraction of the adductor pollicis muscle in response to ulnar nerve stimulation was acceleromyographically quantified. All patients initially received 1 mg/kg rocuronium followed by 0.2 mg/kg whenever the second twitch T2 of the train-of-four (TOF) response reappeared. CO was measured throughout the study using a FloTrac™/Vigileo™ monitor. After completion of surgery and at the reappearance of T2, the time required for a bolus dose of 2 mg/kg sugammadex to facilitate recovery to a TOF ratio of 0.9 was recorded, and its correlation with CO was analysed. Adequate recovery of neuromuscular block was achieved after sugammadex in all patients. Mean CO at the time of reversal with sugammadex was 5.3 l/min (1.3), and recovery time to a TOF ratio of 0.9 was 173.4 s (54.8). A statistically significant inverse correlation was seen between the time to recovery to a TOF ratio of 0.9 and CO [reversal time (s) = -27.7·CO + 298.7, R(2)  = 0.461, P < 0.0001]. The time to reach a TOF ratio of 0.9 following sugammadex is dependent on CO in elderly patients.
    Acta Anaesthesiologica Scandinavica 11/2011; 56(1):83-7. DOI:10.1111/j.1399-6576.2011.02589.x · 2.31 Impact Factor
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    ABSTRACT: This study compared the reversibility of rocuronium-induced profound neuromuscular block with sugammadex in younger and older patients. Fifteen younger (20-50 yr) and 15 older (≥70 yr) patients were sequentially enrolled in this study. After induction of anaesthesia and laryngeal mask insertion, contraction of the adductor pollicis muscle in response to ulnar nerve stimulation was quantified using acceleromyography during 1.0-1.5% end-tidal sevoflurane and remifentanil anaesthesia. All patients initially received rocuronium 1 mg kg(-1), followed by 0.02 mg kg(-1) when a post-tetanic count (PTC) of 1 or 2 was observed. After completion of surgery, at reappearance of 1-2 PTC, the time required for a single bolus dose of 4 mg kg(-1) sugammadex to produce recovery to a train-of-four (TOF) ratio of 0.9 was recorded. There were no differences in the total dose of rocuronium administered between the younger [mean (sd): 93.4 (17.5) mg] and the older [97.5 (32.2) mg] groups. In all patients, adequate recovery of the TOF ratio to 0.9 was achieved after administration of sugammadex, although it was significantly slower in the older [3.6 (0.7) min, P<0.0001] than in the younger group [1.3 (0.3) min]. There were no clinical events attributable to recurarization. Sugammadex can adequately restore neuromuscular function in older patients, although a longer time is required to recover from profound rocuronium-induced neuromuscular block than in younger patients.
    BJA British Journal of Anaesthesia 06/2011; 106(6):823-6. DOI:10.1093/bja/aer098 · 4.35 Impact Factor
  • R Iida, K Iwasaki, J Kato, S Ogawa
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    ABSTRACT: A relationship between the depth of sedation as measured by the bispectral index (BIS) and spinal sensory block height in patients with light to no additional sedation has been described previously. The present study was designed to investigate the hypothesis that BIS values closely correlate with the spread of spinal sensory block in patients deeply sedated with an i.v. target-controlled infusion of propofol. Subjects comprised 100 patients aged 20-64 yr and undergoing arthroscopic knee surgery. Patients were given spinal anaesthesia with bupivacaine 0.5% (3 ml). Propofol was administered to achieve a target effect-site concentration of 3.0 μg ml⁻¹. The relationship between the spinal sensory level at 15 min after spinal anaesthesia and BIS values during 1-5, 6-10, 11-15, and 16-20 min time intervals after the estimated effect-site concentration reached 3.0 μg ml⁻¹ was evaluated. The sensory level of spinal analgesia significantly and strongly correlated with BIS values during each time period after the estimated effect-site concentration remained at 3.0 μg ml⁻¹ (P<0.0001). The correlation coefficient values were 0.8 during 1-5 min, 0.844 during 6-10 min, 0.801 during 11-15 min, and 0.804 during 16-20 min time periods. We demonstrated that BIS values significantly correlate with the level of spinal sensory block under deep sedation with propofol. The depth of sedation induced by spinal anaesthesia depends on the spread of spinal sensory block.
    BJA British Journal of Anaesthesia 02/2011; 106(2):202-7. DOI:10.1093/bja/aeq359 · 4.35 Impact Factor
  • S. Ogawa, H. Tsunoda
    ChemInform 11/2010; 24(45):no-no. DOI:10.1002/chin.199345284
  • ChemInform 10/2010; 23(41):232-232. DOI:10.1002/chin.199241232
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    ABSTRACT: ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.
    ChemInform 09/2010; 27(37). DOI:10.1002/chin.199637291
  • S. OGAWA, S. SASAKI, H. TSUNODA
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    ABSTRACT: ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.
    ChemInform 06/2010; 25(25). DOI:10.1002/chin.199425209
  • H. TSUNODA, S. OGAWA
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    ABSTRACT: ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.
    ChemInform 06/2010; 26(25). DOI:10.1002/chin.199525229
  • [Show abstract] [Hide abstract]
    ABSTRACT: ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.
    ChemInform 06/2010; 26(25). DOI:10.1002/chin.199525230
  • H. Tsunoda, S. Ogawa
    ChemInform 06/2010; 25(23):no-no. DOI:10.1002/chin.199423228
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    ABSTRACT: The low and moderate doses of dexmedetomidine reduce arterial pressure and heart rate (HR), suggesting attenuation of sympathetic activity and dominance of cardiac-vagal activity. These autonomic responses under dexmedetomidine sedation may attenuate cardiovascular reflex responses to temporal reduction in arterial pressure, inducing a severe hypotension. We therefore investigated the effects of dexmedetomidine on cardiovascular reflex responses to temporal reduction in arterial pressure induced by the thigh cuff method. Twelve healthy men received placebo, low-dose (loading 3 microg kg(-1) h(-1) for 10 min; maintenance 0.2 microg kg(-1) h(-1) for 60 min), and moderate-dose (loading 6 microg kg(-1) h(-1) for 10 min; maintenance 0.4 microg kg(-1) h(-1) for 60 min) dexmedetomidine infusions in a randomized, double-blind, crossover study. After 70 min of drug infusion, systolic arterial pressure (SAP) and HR responses after thigh cuff deflation were evaluated as indices of cardiovascular reflex. Reduction in SAP (Delta SAP) [placebo 8 (4), low 12 (4), moderate 19 (5) mm Hg] after thigh cuff deflation was significantly greater in dexmedetomidine than placebo infusions, in a dose-dependent manner. The change in HR (Delta HR), Delta HR/Delta SAP, and the percentage restoration of SAP were lower with dexmedetomidine compared with placebo. The present results indicated that dexmedetomidine weakens arterial pressure preservation and HR responses after thigh cuff deflation, suggesting attenuated cardiovascular reflexes. Therefore, it must be cautioned that dexmedetomidine can lead to further and sustained reduction in arterial pressure during transient hypotension induced by postural changes, haemorrhage, and/or other stresses.
    BJA British Journal of Anaesthesia 09/2009; 103(4):561-5. DOI:10.1093/bja/aep210 · 4.35 Impact Factor
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    ABSTRACT: The aim of this study is to compare the infusion rates required to maintain a constant neuromuscular block and the reversibility of rocuronium at the corrugator supercilii muscle (CSM) and the adductor pollicis muscle (APM). We randomly allocated 30 female patients into two groups of 15 patients each to monitor neuromuscular block at either the CSM or the APM. After induction of anaesthesia and laryngeal mask insertion, contraction of the CSM to the facial nerve stimulation or that of the APM to the ulnar nerve stimulation was quantified using an acceleromyograph during 1.0-1.5% end-tidal sevoflurane anaesthesia. All the patients received a bolus of 1 mg/kg rocuronium. When the first twitch (T1) of train-of-four (TOF) recovered to 10% of the control, rocuronium infusion was commenced and maintained at T1 of 10% of the control at the CSM or APM for 120 min. Immediately after rocuronium infusion was discontinued, the time required for 0.04 mg/kg neostigmine-facilitated recovery to a TOF ratio of 0.9 was recorded. Rocuronium infusion dose after a lapse of 120 min was significantly larger in the CSM than in the APM [7.1 (2.3) vs. 4.7 (2.6) microg/kg/min; P=0.001]. The time for facilitated recovery was shorter in the CSM than in the APM [11.4 (3.8) vs. 16.2 (6.0) min; P=0.016]. A larger rocuronium infusion dose was required to maintain a constant neuromuscular block at the CSM. Neostigmine-mediated reversal was faster at the CSM.
    Acta Anaesthesiologica Scandinavica 08/2009; 53(10):1336-40. DOI:10.1111/j.1399-6576.2009.02073.x · 2.31 Impact Factor
  • R Iida, J Kato, S Ogawa
    Acta Anaesthesiologica Scandinavica 10/2008; 52(8):1169-71. DOI:10.1111/j.1399-6576.2008.01699.x · 2.31 Impact Factor
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    ABSTRACT: The aim of this study was to examine the efficacy of epidurally administered mepivacaine on recovery from vecuronium-induced neuromuscular block. Eighty patients were randomly assigned to one of two study groups. They were either given epidurally a bolus of 0.15 ml kg(-1) of mepivacaine 2%, followed by repetitive injections of 0.1 ml kg(-1) h(-1) throughout the study, or were not given epidurally. General anaesthesia was induced and maintained with fentanyl, propofol and nitrous oxide. Neuromuscular block was induced with vecuronium 0.1 mg kg(-1) and monitored using acceleromyographic train-of-four (TOF) at the adductor pollicis. Patients in each treatment group were randomized to receive neostigmine 0.04 mg kg(-1) at 25% recovery of the first twitch of TOF or to recover spontaneously to a TOF ratio of 0.9. The effect of epidural mepivacaine on speed of spontaneous and facilitated recovery of neuromuscular function was evaluated. The time from administration of vecuronium to spontaneous recovery to a TOF ratio of 0.9 was significantly longer in the epidural mepivacaine group [105.4 (14.2) min] as compared with the control group [78.5 (9.1) min, P < 0.01]. Neostigmine administered at 25% of control in T1 shortened recovery from neuromuscular block, however the time required for facilitated recovery to a TOF ratio of 0.9 in the epidural group was significantly longer than that in the control group [7.6 (1.6) min vs 5.8 (2.1) min, P < 0.01]. In clinical anaesthesia, it should be recognized that epidurally administered mepivacaine delays considerably the TOF recovery from neuromuscular block.
    BJA British Journal of Anaesthesia 12/2007; 99(5):721-5. DOI:10.1093/bja/aem253 · 4.35 Impact Factor
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    ABSTRACT: This study was designed to recognize the importance of normalizing postoperative acceleromyographic train-of-four (TOF) ratio by the baseline TOF value obtained before neuromuscular block for ensuring adequate recovery of neuromuscular function. In 120 patients, TOF responses of the adductor pollicis to the ulnar nerve stimulation were monitored by acceleromyography (AMG) during anaesthesia using propofol, fentanyl and nitrous oxide. Control TOF stimuli were administered for 30 min. A TOF ratio measured at the end of control stimulation was regarded as a baseline value. Neuromuscular block was induced with vecuronium 0.1 mg kg(-1) and was allowed to recover spontaneously. Duration to a TOF ratio of 0.9 as calculated by AMG (DUR-raw 0.9) was compared with that of 0.9 as corrected by the baseline TOF ratio (i.e. 0.9 x baseline TOF ratio; DUR-real 0.9). Baseline TOF ratios ranged from 0.95 to 1.47. The average TOF ratios observed every 5 min were constant throughout control stimulation from at time zero mean (SD) [range]; 1.11 (0.09) [0.94-1.42] to at 30 min 1.13 (0.11) [0.95-1.47]. The DUR-real 0.9 was 91.0 (18.0) [51.3-131.0] min and was significantly longer than the DUR-raw 0.9 (81.2 (16.3) [41.3-123.0] min). Baseline TOF ratios measured by AMG are usually more than 1.0 and vary widely among patients. Therefore a TOF ratio of 0.9 displayed postoperatively on AMG does not always represent adequate recovery of neuromuscular function and should be normalized by baseline value to reliably detect residual paralysis.
    BJA British Journal of Anaesthesia 02/2006; 96(1):44-7. DOI:10.1093/bja/aei273 · 4.35 Impact Factor
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    ABSTRACT: Ropivacaine, a new long acting local anaesthetic of amide type is structurally related to mepivacaine and bupivacaine. This study was designed to compare the in vitro potency and neurotoxicity of ropivacaine with those of other commercially available local anaesthetics using an isolated rabbit vagus nerve model. Ropivacaine dose-dependently suppressed the evoked compound action potentials of A beta nerve and C nerve components. Minimum concentration of ropivacaine for producing complete suppression of the compound action potentials of all components was 0.008%. Electron microscopic observation showed that ropivacaine did not destroy any peripheral nervous structures in concentrations up to 0.75%. When the neurotoxic effect of ropivacaine was compared, in terms of risk ratio (clinically used concentration/concentrations producing 2 hr irreversible block), with that of commercially available local anesthetics, the rank oder was dibucaine, tetracaine, lidocaine, bupivacaine and ropivacaine.
    Masui. The Japanese journal of anesthesiology 01/2002; 50(12):1308-15.
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    ABSTRACT: The purpose of this study was to quantify the relationship between the dose-response curve of vecuronium and duration of exposure to an end-tidal concentration of 1.7% sevoflurane in 67% nitrous oxide and oxygen. Forty adult patients, in groups of 10, were allocated randomly to receive vecuronium by a cumulative dose method at intervals of 15 min (group 15), 30 min (group 30), 60 min (group 60) or 90 min (group 90) after starting inhalation of sevoflurane. Neuromuscular function was monitored by acceleromyographic train-of-four (TOF) responses of the adductor pollicis muscle to ulnar nerve stimulation. Dose-response curves were constructed by least-squares regression analysis and the effective doses of vecuronium (ED50, ED90 and ED95) were estimated and compared between groups. Mean (SEM) ED50, ED90 and ED95 were 16.8 (0.5), 32.6 (1.7) and 40.9 (2.4) micrograms kg-1, respectively, in group 15; 10.6 (1.0), 20.8 (1.7) and 26.2 (2.2) micrograms kg-1, respectively, in group 30; 11.2 (1.1), 21.7 (1.6) and 27.3 (1.8) micrograms kg-1, respectively, in group 60; and 11.0 (1.1), 21.7 (1.6) and 27.5 (1.9) micrograms kg-1, respectively, in group 90. The values obtained in group 15 were significantly higher than those in the other three groups (P < 0.05). The results indicate that the duration of sevoflurane anaesthesia influences the dose-response of vecuronium and 30 min inhalation of 1.7% end-tidal concentration is sufficient to achieve a stable potentiating effect.
    BJA British Journal of Anaesthesia 12/2000; 85(5):732-4. DOI:10.1093/bja/85.5.732 · 4.35 Impact Factor
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    ABSTRACT: Preoperative patients have various kinds of anxiety. However we do not know much about their psychological burden. Therefore, we investigated types of their anxiety with questionnaires prior to operation and analyzed them according to their anesthetic method, type of surgery and age. Concerning anesthetic methods, patients' anxiety varied depending on their histories of anesthesia, anesthetic method previously received and age. Concerning the type of surgery, patients scheduled to undergo abdominal and cardiac surgery had more intense anxiety. Patients scheduled for gynecological surgery were anxious about the accident which might be induced by anesthesia. A large number of patients scheduled for orthopedic surgery were anxious about postoperative pain. Concerning patients' age, patients whose ages ranged from 10s to 50s were anxious about pain. While, in patients over 60s, their anxiety was focussed on giving trouble to their surrounding people. Patients whose age was 10 to 19 had anxiety about their anesthetic method. Anesthesiologists should recognize that preoperative patients have various kinds of anxiety. It is important for us to examine the patients appropriately according to their psychological and physical condition.
    Masui. The Japanese journal of anesthesiology 09/2000; 49(8):913-9.

Publication Stats

208 Citations
58.71 Total Impact Points

Institutions

  • 2000–2012
    • Nihon University
      • Department of Dental Anesthesiology
      Edo, Tōkyō, Japan
  • 2010
    • Keio University
      • Department of Applied Chemistry
      Edo, Tōkyō, Japan
  • 2007–2009
    • Surugadai University
      Edo, Tōkyō, Japan
  • 1990–2000
    • Tokyo Medical University
      • Department of Anesthesiology
      Edo, Tōkyō, Japan
  • 1996
    • Kochi Medical School
      Kôti, Kōchi, Japan