岡山医学会 Acta Medica Okayama 0030-1558 127 1 2015 岡山大学医療教育統合開発センターの医療教育に対する取り組み 51 54 EN Naoki Shiba No potential conflict of interest relevant to this article was reported.

Okayama University Medical School Acta Medica Okayama 0386-300X 68 6 2014 Mean Lung Pressure during Adult High-Frequency Oscillatory Ventilation: An Experimental Study Using a Lung Model 323 329 EN Takahiro Hirayama Osamu Nagano Naoki Shiba Tetsuya Yumoto Keiji Sato Michihisa Terado Toyomu Ugawa Shingo Ichiba Yoshihito Ujike Original Article 10.18926/AMO/53021 In adult high-frequency oscillatory ventilation (HFOV), stroke volume (SV) and mean lung pressure (PLung) are important for lung protection. We measured the airway pressure at the Y-piece and the lung pressure during HFOV using a lung model and HFOV ventilators for adults (R100 and 3100B). The lung model was made of a 20-liter, airtight rigid plastic container (adiabatic compliance: 19.3ml/cmH₂O) with or without a resistor (20cmH₂O/l/sec). The ventilator settings were as follows: mean airway pressure (MAP), 30cmH2O;frequency, 5-15Hz (every 1Hz);airway pressure amplitude (AMP), maximum;and % of inspiratory time (IT), 50% for R100, 33% or 50% for 3100B. The measurements were also performed with an AMP of 2/3 or 1/3 maximum at 5, 10 and 15Hz. The PLung and the measured MAP were not consistently identical to the setting MAP in either ventilator, and decreasing IT decreased the PLung in 3100B. In conclusion, we must pay attention to the possible discrepancy between the PLung and the setting MAP during adult HFOV. No potential conflict of interest relevant to this article was reported.

Okayama University Medical School Acta Medica Okayama 0386-300X 66 6 2012 Evaluating the Need for and Effect of Percutaneous Transluminal Angioplasty on Arteriovenous Fistulas by Using Total Recirculation Rate per Dialysis Session (“Clearance Gap”) 443 447 EN Toyomu Ugawa Kazufumi Sakurama Takashi Yorifuji Munenori Takaoka Yasuhiro Fujiwara Narutoshi Kabashima Daisuke Azuma Takahiro Hirayama Kohei Tsukahara Sunao Morisada Atsuyoshi Iida Keitaro Tada Naoki Shiba Nobuo Sato Shingo Ichiba Koichi Kino Masaki Fukushima Yoshihito Ujike Original Article 10.18926/AMO/49040 The functioning of an arteriovenous fistula (AVF) used for vascular access during hemodialysis has been assessed mainly by dilution methods. Although these techniques indicate the immediate recirculation rate, the results obtained may not correlate with Kt/V. In contrast, the clearance gap (CL-Gap) method provides the total recirculation rate per dialysis session and correlates well with Kt/V. We assessed the correlation between Kt/V and CL-Gap as well as the change in radial artery (RA) blood flow speed in the fistula before percutaneous transluminal angioplasty (PTA) in 45 patients undergoing continuous hemodialysis. The dialysis dose during the determination of CL-Gap was 1.2 to 1.4 Kt/V. Patients with a 10% elevation or more than a 10% relative increase in CL-Gap underwent PTA (n＝45), and the values obtained for Kt/V and CL-Gap before PTA were compared with those obtained immediately afterward. The mean RA blood flow speed improved significantly (from 52.9 to 97.5cm/sec) after PTA, as did Kt/V (1.07 to 1.30) and CL-Gap (14.1% to －0.2%). A significant correlation between these differences was apparent (r＝－0.436 and p＝0.003). These findings suggest that calculating CL-Gap may be useful for determining when PTA is required and for assessing the effectiveness of PTA, toward obtaining better dialysis. No potential conflict of interest relevant to this article was reported.

Okayama University Medical School Acta Medica Okayama 0386-300X 66 4 2012 Humidification of Base Flow Gas during Adult High-Frequency Oscillatory Ventilation:An Experimental Study Using a Lung Model 335 341 EN Naoki Shiba Osamu Nagano Takahiro Hirayama Shingo Ichiba Yoshihito Ujike Original Article 10.18926/AMO/48688 In adult high-frequency oscillatory ventilation (HFOV) with an R100 artificial ventilator, exhaled gas from patientʼs lung may warm the temperature probe and thereby disturb the humidification of base flow (BF) gas. We measured the humidity of BF gas during HFOV with frequencies of 6, 8 and 10Hz, maximum stroke volumes (SV) of 285, 205, and 160ml at the respective frequencies, and, BFs of 20, 30, 40l/min using an original lung model. The R100 device was equipped with a heated humidifier, HummaxⅡ, consisting of a porous hollow fiber in circuit. A 50-cm length of circuit was added between temperature probe (located at 50cm proximal from Y-piece) and the hollow fiber. The lung model was made of a plastic container and a circuit equipped with another HummaxⅡ. The lung model temperature was controlled at 37℃. The HummaxⅡ of the R100 was inactivated in study-1 and was set at 35℃ or 37℃ in study-2. The humidity was measured at the distal end of the added circuit in study-1 and at the proximal end in study-2. In study-1, humidity was detected at 6Hz (SV 285ml) and BF 20l/min, indicating the direct reach of the exhaled gas from the lung model to the temperature probe. In study-2 the absolute humidity of the BF gas decreased by increasing SV and by increasing BF and it was low with setting of 35℃. In this study setting, increasing the SV induced significant reduction of humidification of the BF gas during HFOV with R100. No potential conflict of interest relevant to this article was reported.