Hidenori Toyooka

The Ottawa Hospital, Ottawa, Ontario, Canada

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Publications (291)740.84 Total impact

  • Yoshitaka Fujii · Hidenori Toyooka
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    ABSTRACT: Purpose: To evaluate the effects of colforsin daropate, a water-soluble derivate known to improve contractility in fatigued canine diaphragm, at two different doses (low-dose and high-dose) on contractility of the non-fatigued diaphragm of dogs. Methods: Twenty-four pentobarbitone-anesthetized dogs were divided into three groups of eight each: Group I received no study drug; Group 11 received low-dose (0.2 mug.kg(-1).min(-1)) colforsin daropate; Group III received high-dose (0.5 mug.kg(-1).min(-1)) colforsin daropate. Diaphragmatic contractility was assessed by transdiaphragmatic pressure (Pdi). Results: In Group III, with an infusion of high-dose colforsin daropate, Pdi at low-frequency (20 Hz) and high-frequency (100 Hz) stimulation increased from baseline values (P < 0.05). Compared with Group 1, Pdi at both stimuli increased during colforsin daropate administration in Group III (P < 0.05). In Group 11, with an infusion of low- dose colforsin daropate, Pdi to each stimulus did not change. Conclusion: Colforsin daropate, only when administered at high-dose, increases contractility of non-fatigued diaphragm in dogs.
    No preview · Article · Jun 2013 · Canadian Journal of Anaesthesia
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    Yoshitaka Fujii · Yuhji Saitoh · Hiroyoshi Tanaka · Hidenori Toyooka

    Full-text · Article · May 2013 · Canadian Anaesthetists? Society Journal
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    Yoshitaka Fujii · Hidenori Toyooka · Hiroyoshi Tanaka

    Preview · Article · May 2013 · Canadian Anaesthetists? Society Journal
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    Yoshitaka Fujii · Hidenori Toyooka · Hiroyoshi Tanaka

    Preview · Article · May 2013 · Canadian Anaesthetists? Society Journal
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    Yoshitaka Fujii · Yuhji Saitoh · Hiroyoshi Tanaka · Hidenori Toyooka

    Full-text · Article · May 2013 · Canadian Anaesthetists? Society Journal
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    Preview · Article · Apr 2013 · Canadian Anaesthetists? Society Journal
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    Yoshitaka Fujii · Yuhji Saitoh · Hiroyoshi Tanaka · Hidenori Toyooka

    Full-text · Article · Apr 2013 · Canadian Anaesthetists? Society Journal
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    Takuo Hoshi · Yoshitaka Fujii · Shinji Takahashi · Hidenori Toyooka
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    ABSTRACT: Purpose: This study was undertaken to examine the effect of xenon on diaphragmatic contractility in pentobarbitone- anesthetized, mechanically ventilated dogs. Methods: Twenty-one dogs were randomly allocated to three groups (n=7 of each): Group I received oxygen 100%; Group II received xenon 30% in oxygen; Group III received xenon 60% in oxygen. Diaphragmatic contractility was assessed by measuring transdiaphragmatic pressure (Pdi) generated during supramaximal stimulation of phrenic nerves at the neck at low-frequency (20-Hz) and high-frequency (100-Hz) stimulation, after maintaining 60 min of stable condition. Results: With inhalation of xenon at two different concentration (30% and 60%), no changes were observed in Pdi at either concentration. There was no difference in Pdi among the three groups. Conclusion: Increasing the concentration of xenon to 60% has no effect on diaphragmatic contractility in dogs. This suggests that xenon may be used safely as an anesthetic with respect to respiratory muscle function.
    Full-text · Article · Apr 2013 · Canadian Anaesthetists? Society Journal
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    Yoshitaka Fujii · Yuhji Saitoh · Shinji Takahashi · Hidenori Toyooka
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    ABSTRACT: Purpose: Hypertensive patients exhibit exaggerated cardiovascular responses to tracheal extubation, This study was undertaken to compare the efficacy of combined ditiazem and lidocaine with each drug alone in suppressing the hemodynamic changes during tracheal extubation. Methods: Sixty hypertensive patients (ASA II), defined as systolic blood pressure > 160 mmHg and/or diastolic blood pressure > 95 mmHg (WHO), undergoing elective orthopedic surgery received, in a randomized, double-blind manner, 0.2 mg.kg(-1) diltiazem, 1.0 mg.kg(-1) lidocaine, or 0.2 mg.kg(-1) diltiazem plus 1.0 mg.kg(-1) lidocaine (n = 20 of each) iv before tracheal extubation, Changes in heart rate (HR), mean arterial pressure (MAP) and rate-pressure product (RPP) were measured before and after tracheal extubation. Results: Hemodynamic changes during tracheal extubation were less in patients receiving diltiazem plus lidocaine than in those receiving ditiazem or lidocaine as a sole medicine (RPP; 10322 +/- 1674 (combined) vs 11532 +/- 1802 (diltiazem), 15388 +/- 2050 (lidocaine), mean +/- SD, P < 0.05). Conclusion: Combined diltiazem and lidocaine is more effective prophylaxis than diltiazem or lidocaine alone for attenuating the cardiovascular responses to tracheal extubation and emergence from anesthesia in hypertensive patients.
    Full-text · Article · Apr 2013 · Canadian Anaesthetists? Society Journal
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    Yoshitaka Fujii · Hidenori Toyooka

    Preview · Article · Apr 2013 · Canadian Anaesthetists? Society Journal
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    Yoshitaka Fujii · Hidenori Toyooka · Keisuke Amaha

    Preview · Article · Nov 2012 · Canadian Anaesthetists? Society Journal
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    Yoshitaka Fujii · Hiroyoshi Tanaka · Yuhji Saitoh · Hidenori Toyooka
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    ABSTRACT: We studied the circulatory responses to laryngoscopy and tracheal intubation in 37 hypertensive patients who received nicardipine 30 μg · kg−1 iv (Group N, n = 12), diltiazem 0.3 mg · kg−1 (Group D, n = 12) or saline placebo (Group C, n = 13) 60 sec before the initiation of laryngoscopy. Anaesthesia was induced with thiopentone 5 mg · kg−1 iv, and succinylcholine 2 mg · kg−1 iv was used to facilitate tracheal intubation after precurarization with vecuronium 0.02 mg · kg−1 iv. In patients in Group C heart rate (HR) increased from 79 ± 14 (baseline) to 110 ± 12 (P < 0.05) associated with tracheal intubation; mean arterial pressure (MAP) increased from 116 ± 8 to 140 ± 77 (P < 0.05) and rate-pressure product (RPP) increased from 13385 ± 2393 to 21251 ± 3883 (P < 0.05). The changes from baseline values in HR and RPP after tracheal intubation in Group D were less than those in Groups C and N (P < 0.05). The increase in MAP following tracheal intubation in Groups N and D was lower than that in Group C (P < 0.05). We conclude that, compared with nicardipine, administration of diltiazem iv is associated with less circulatory response to tracheal intubation in hypertensive patients.
    Full-text · Article · Nov 2012 · Canadian Anaesthetists? Society Journal
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    Yoshitaka Fujii · Hiroyoshi Tanaka · Hidenori Toyooka
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    ABSTRACT: The effects of laryngeal mask airway (LMA) insertion and tracheal intubation on circulatory responses were studied in normotensive (n = 24) and hypertensive (n = 22) patients. In a randomized, double-blind manner, LMA insertion or tracheal intubation was performed after induction of anaesthesia with thiopentone and muscle relaxation with succinylcholine. In both normotensive and hypertensive patients, heart rate (HR), mean arterial pressure (MAP) and rate-pressure product increased after tracheal intubation or LMA insertion compared with base-line (P < 0.05). The haemodynamic changes were greater after intubation than after LMA insertion (P < 0.05). Following intubation of the trachea or insertion of the LMA, HR increased more markedly in hypertensive patients than in normotensive patients (P < 0.05). Plasma adrenaline and noradrenaline concentrations after tracheal intubation or LMA insertion increased compared with baseline values (P < 0.05) in normotensive and hypertensive patients. The increase in noradrenaline concentration after tracheal intubation was greater than that after LMA insertion (P < 0.05). No patient revealed ECG evidence of myocardial ischaemia. We conclude that insertion of LMA is associated with less circulatory responses than tracheal intubation in both normotensive and hypertensive patients.
    Preview · Article · Nov 2012 · Canadian Anaesthetists? Society Journal
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    Yoshitaka Fujii · Hiroyoshi Tanaka · Hidenori Toyooka
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    ABSTRACT: The antiemetic effects of granisetron, a selective 5-hydroxy-tryptamine type 3 receptor antagonist, on postoperative nausea and vomiting were studied and compared with placebo and metoclopramide in 60 patients undergoing general anaesthesia for major gynaecological surgery. The patients received a single iv dose of either granisetron (3 mg, n = 20) metoclopramide (10 mg, n = 20), or placebo (saline, n = 20) immediately after recovery from anaesthesia. The effects were assessed during the first three and the next 21 hr after recovery from anaesthesia by means of a nausea and vomiting score; 0 = no emetic symptoms, 1 = nausea, 2 = vomiting. The mean scores during 0–3 hr were 0.8, 0.1 and 0.1 after administration of placebo, metoclopramide and granisetron, respectively; the corresponding scores during 3–24 hr were 0.6, 0.5 and 0.1. The scores of the metoclopramide and the granisetron groups were different from the placebo group in the first three hours (P < 0.05). Although there were no differences in the scores during 0–3 hr between the metoclopramide and the granisetron groups, there were differences during 3–24 hr (P < 0.05). It is concluded that granisetron is superior to metoclopramide in the long-term prevention of postoperative nausea and vomiting after anaesthesia.
    Preview · Article · Nov 2012 · Canadian Anaesthetists? Society Journal
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    Yoshitaka Fujii · Hiroyoshi Tanaka · Hidenori Toyooka
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    ABSTRACT: The prophylactic antiemetic efficacy of combined granisetron and dexamethasone was evaluated in a randomized doubleblind manner in 88 patients undergoing general anaesthesia for major gynaecological surgery. Immediately after recovery from anaesthesia, patients received a single dose of either placebo (saline, n = 22), granisetron (20 μg · kg− 1, n = 22), dexamethasone (8 mg, n = 22) or combined granisetron and dexamethasone (20 μg · kg− 1 and 8 mg, respectively, n = 22) iv. The treatment groups were similar for patient demography, surgical procedures, anaesthetics administered and opioids given. Postoperatively, the frequency of nausea was 32%, 23%, 27% and 5% after administration of placebo, granisetron, dexamethasone and granisetron plus dexamethasone, respectively; the corresponding frequencies of vomiting were 23%, 23%, 23% and 5%. The incidence of adverse events postoperatively were not different among the groups. It is concluded that prophylactic administration of combined granisetron and dexamethasone is effective in preventing postoperative nausea and vomiting after anaesthesia.
    Preview · Article · Nov 2012 · Canadian Anaesthetists? Society Journal
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    Yoshitaka Fujii · Hidenori Toyooka · Toshiya Ebata · Keisuke Amaha

    Preview · Article · Nov 2012 · Canadian Anaesthetists? Society Journal
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    Yoshitaka Fujii · Hidenori Toyooka · Keisuke Amaha

    Preview · Article · Nov 2012 · Canadian Anaesthetists? Society Journal
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    Yoshitaka Fujii · Hiroyoshi Tanaka · Hidenori Toyooka
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    ABSTRACT: Purpose Dexamethasone decreases chemotherapy-induced emesis when added to antiemetic regimens. This study was designed to compare the effectiveness of granisetron and dexamethasone with granisetron alone in the prevention of postoperative vomiting after strabismus repair, tonsillectomy with or without adenoidectomy in children. Methods In a randomized, double-blind study, 60 healthy children, 4–10 yr of age, received either granisetron 40 μg · kg−1 and saline (Group S) or granisetron 40 μg · kg−1 and dexamethasone 4 mg (Group D) iv immediately after the induction of anaesthesia. All subjects received anaesthetics consisting of sevoflurane and nitrous oxide in oxygen. Postoperative pain was treated with acetaminophen pr or pentazocine iv. Postoperatively, during the first 24 hr after anaesthesia, the frequencies of retching and vomiting, and the incidence of adverse events were recorded by nursing staff. Results There were no differences between the treatment groups with regard to demographics, surgical procedure, anaesthetic administered or analgesics used for postoperative pain. The frequency of the symptoms was 27% and 7% in Groups S and D, respectively (P < 0.05). The incidence of adverse events was comparable in the two groups. Conclusion The prophylactic administration of granisetron and dexamethasone was more effective than granisetron alone in the prevention of postoperative vomiting in paediatric subjects undergoing strabismus repair, tonsillectomy and adenoidectomy.
    Preview · Article · Nov 2012 · Canadian Anaesthetists? Society Journal
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    Yoshitaka Fujii · Hidenori Toyooka · Hiroyoshi Tanaka
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    ABSTRACT: Purpose This study was to identify the minimum effective dose of granisetron, a selective 5-hydroxytryptamine type 3 receptor antagonist, to prevent postoperative vomiting in children who have undergone strabismus repair, tonsillectomy or tonsillectomy with adenoidectomy. Methods In a randomized, double-blind fashion, 80 healthy children aged 4–10 yr were assigned to receive either placebo (saline) or granisetron in a dose of 20, 40 or 80 μg· kg−1 iv immediately following the induction of anaesthesia. All subjects received a standardized anaesthetic, which consisted of sevoflurane in nitrous oxide and oxygen. Rescue antiemetics were administered if two or more episodes of vomiting occurred. Postoperative pain was treated with acetaminophene pr or pentazocine iv. During the first 24 hr after anaesthesia, the frequencies of retching and vomiting were recorded in a standardized fashion by nursing staff while subjects were in a hospital. Results There were no differences among four treatment groups with regard to subject characteristics, surgical procedures, anaesthetic and postoperative management or adverse effects. The frequencies of these symptoms were as follows: 65%, 60%, 20% and 15% after administration of placebo, granisetron 20, 40 or 80 μg· kg−1. Three children who had received either placebo or granisetron 20 μg · kg−1 required another rescue antiemetic drug, whereas none who had received granisetron 40 or 80 μg · kg−1 needed rescue drugs. Conclusion Granisetron 40 μg · kg−1 is an effective antiemetic for preventing retching and vomiting following strabismus repair and tonsillectomy in children. Increasing the dose to 80 μg ·kg −1 provided no demonstrable benefit in reducing postoperative emesis.
    Preview · Article · Nov 2012 · Canadian Anaesthetists? Society Journal
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    Yoshitaka Fujii · Hidenori Toyooka · Hiroyoshi Tanaka
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    ABSTRACT: Purpose This randomized, placebo-controlled, double-blind study was to evaluate the effects of granisetron, a selective 5-hydroxytryptamine type 3 receptor antagonist, for preventing postoperative nausea and vomiting in 110 patients with (n = 50) and without (n = 60) a history of motion sickness undergoing general anaesthesia for major gynaecological surgery. Methods The patients received a single dose of either granisetron (40 μg · kg−1) or placebo (saline) iv over 2–5 min immediately before induction of anaesthesia. Postoperatively, during the first 24 hr after anaesthesia, the frequencies of nausea and vomiting were recorded. Results Except for a positive history of motion sickness, the treatment groups were similar for patient characteristics, types of surgery, anaesthetics administered and opioids given. Postoperatively, the frequency of nausea was 44% and 16% after administration of placebo and granisetron in patients with motion sickness, and was 30% and 7% in patients without it, respectively; the corresponding frequencies of vomiting were 28%, 8%, 13% and 3%. The incidence of adverse events postoperatively were not different among the groups. Conclusion These results suggest that preoperative prophylactic administration of granisetron is effective and safe for preventing postoperative nausea and vomiting in patients with motion sickness as well as in patients without it.
    Preview · Article · Nov 2012 · Canadian Anaesthetists? Society Journal

Publication Stats

4k Citations
740.84 Total Impact Points

Institutions

  • 2012-2013
    • The Ottawa Hospital
      Ottawa, Ontario, Canada
  • 1997-2013
    • University of Tsukuba
      • • Department of Anesthesiology
      • • Institute of Clinical Medicine
      Tsukuba, Ibaraki-ken, Japan
  • 2011-2012
    • Teikyo University Hospital
      Edo, Tokyo, Japan
  • 1995-2012
    • Tsuchiura Kyodo General Hospital
      Tsukuba, Ibaraki, Japan
  • 1987-2012
    • Tokyo Medical and Dental University
      • • Department of Critical Care Medicine
      • • Department of Medicine
      • • Faculty of Medicine
      • • Institute for Medical and Dental Engineering
      • • Department of Anesthesiology
      Edo, Tōkyō, Japan
  • 2006
    • Teikyo University
      • Department of Anesthesiology
      Edo, Tōkyō, Japan