Current Issue : July - September Volume : 2014 Issue Number : 3 Articles : 6 Articles
Background: Intermittent pneumatic compression (IPC) improves haemodynamics in peripheral arterial disease\r\n(PAD), but its effects on foot perfusion were scarcely studied. In severe PAD patients we measured the foot\r\noxygenation changes evoked by a novel intermittent IPC device (GP), haemodynamics and compliance to the\r\ntreatment. Reference values were obtained by a sequential foot-calf device (SFC).\r\nMethods: Twenty ischemic limbs (Ankle-Brachial Index = 0.5 �± 0.2) of 12 PAD patients (7 male, age: 74.5 �± 10.8 y)\r\nwith an interval of 48 �± 2 hours received a 35 minute treatment in supine position with two IPC devices: i) a\r\nGradient Pump (GP), which slowly inflates a single thigh special sleeve and ii) an SFC (ArtAssist�®, ACI Medical, San\r\nMarcos, CA, USA), which rapidly inflates two foot-calf sleeves. Main outcome measure: changes of oxygenated\r\nhaemoglobin at foot (HbO2foot) by continuous near-infrared spectroscopy recording and quantified as area-under-curve\r\n(AUC) for periods of 5 minutes. Other measures: haemodynamics by echo-colour Doppler (time average velocity (TAV)\r\nand blood flow (BF) in the popliteal artery and in the femoral vein), patient compliance by a properly developed form.\r\nResults: All patients completed the treatment with GP, 9 with SFC. HbO2foot during the working phase, considered as\r\naverage value of the 5 minutes periods, increased with GP (AUC 458 �± 600 to 1216 �± 280) and decreased with SFC\r\n(AUC 231 �± 946 to -1088 �± 346), significantly for most periods (P < 0.05). The GP treatment was associated to significant\r\nhaemodynamic changes from baseline to end of the treatment (TAV = 10.2 �± 3.3 to 13.5 �± 5.5 cm/sec, P = 0.004; BF =\r\n452.0 �± 187.2 to 607.9 �± 237.8 ml/sec, P = 0.0001), not observed with SFC (TAV = 11.2 �± 3.4 to 11.8 �± 4.3 cm/sec; BF =\r\n513.8 �± 203.7 to 505.9 �± 166.5 ml/min, P = n.s.). GP obtained a higher score of patient compliance (P < 0.0001).\r\nConclusions: A novel IPC thigh device, unlike a traditional SFC device, increased foot oxygenation in severe PAD,\r\ntogether with favourable haemodynamic response and high compliance to the treatment under the present\r\nexperimental conditions....
Background: Medical devices are continuously being improved in routine clinical practice. As necessary, new or\r\nadditional clinical data for an investigational medical device is collected through clinical research and/or registered clinical\r\ninvestigations. We conducted a questionnaire survey to determine the current environment for clinical research with medical\r\ndevices, particularly focusing on infrastructure and human resources in hospitals.\r\nMethods: The questionnaire for this study included 6 main topics: experience of clinical research, in-hospital manuals,\r\nissues on clinical research, related regulations, and effectiveness of a guidance published by the Medical Engineering\r\nTechnology Industrial Strategy Consortium. The questionnaire was mailed to all 10 core clinical research centers and 30\r\nmajor clinical trial institutions at the time of survey in Japan.\r\nResults: Eighteen hospitals (45%) provided responses. Relatively few clinical research activities with medical devices\r\nhad been conducted in each hospital, and two-thirds of respondents thought low number of clinical research activities was\r\nproblematic. A shortage of experts in medical devices was also raised as an important challenge. Most of the hospitals\r\n \r\n \r\n \r\n \r\n\r\n \r\n \r\n \Z \r\nevaluation of medical devices might not be included in the manuals. Many hospitals had too few clinical research coordinators\r\n(CRCs) for support of clinical research with medical devices, but half of the hospitals could not afford to increase the number\r\nof CRCs.\r\nConclusion: Our study revealed that the current environment for clinical research with medical devices in hospitals has\r\nbeen partly organized, but it was suggested that a shortage of experts, the complexity of the regulatory system, and a need\r\n \r\n ...
Background: When using a pulsatile left ventricular assist device (LVAD), it is\r\nimportant to reduce the cardiac load variations of the native heart because severe\r\ncardiac load variations can induce ventricular arrhythmia. In this study, we\r\ninvestigated the effect of counter-pulsation control of the LVAD on the reduction of\r\ncardiac load variation.\r\nMethods: A ventricular electrocardiogram-based counter-pulsation control algorithm\r\nfor a LVAD was implemented, and the effects of counter-pulsation control of the\r\nLVAD on the reduction of the working load variations of the left ventricle were\r\ndetermined in three animal experiments.\r\nResults: Deviations of the working load of the left ventricle were reduced by 51.3%,\r\n67.9%, and 71.5% in each case, and the beat-to-beat variation rates in the working load\r\nwere reduced by 84.8%, 82.7%, and 88.2% in each ease after counter-pulsation control.\r\nThere were 3 to 12 premature ventricle contractions (PVCs) before counter-pulsation\r\ncontrol, but no PVCs were observed during counter-pulsation control.\r\nConclusions: Counter-pulsation control of the pulsatile LVAD can reduce severe cardiac\r\nload variations, but the average working load is not markedly affected by application of\r\ncounter-pulsation control because it is also influenced by temporary cardiac outflow\r\nvariations. We believe that counter-pulsation control of the LVAD can improve the\r\nlong-term safety of heart failure patients equipped with LVADs....
Background: According to the latest amendment of the Medical Device Directive standalone software qualifies as\r\na medical device when intended by the manufacturer to be used for medical purposes. In this context, the EN\r\n62304 standard is applicable which defines the life-cycle requirements for the development and maintenance of\r\nmedical device software. A pilot project was launched to acquire skills in implementing this standard in a\r\nhospital-based environment (in-house manufacture).\r\nMethods: The EN 62304 standard outlines minimum requirements for each stage of the software life-cycle, defines\r\nthe activities and tasks to be performed and scales documentation and testing according to its criticality. The\r\nrequired processes were established for the pre-existent decision-support software FlashDumpComparator (FDC)\r\nused during the quality assurance of treatment-relevant beam parameters. As the EN 62304 standard implicates\r\ncompliance with the EN ISO 14971 standard on the application of risk management to medical devices, a risk\r\nanalysis was carried out to identify potential hazards and reduce the associated risks to acceptable levels.\r\nResults: The EN 62304 standard is difficult to implement without proper tools, thus open-source software was\r\nselected and integrated into a dedicated development platform. The control measures yielded by the risk analysis\r\nwere independently implemented and verified, and a script-based test automation was retrofitted to reduce the\r\nassociated test effort. After all documents facilitating the traceability of the specified requirements to the\r\ncorresponding tests and of the control measures to the proof of execution were generated, the FDC was released\r\nas an accessory to the HIT facility.\r\nConclusions: The implementation of the EN 62304 standard was time-consuming, and a learning curve had to be\r\novercome during the first iterations of the associated processes, but many process descriptions and all software\r\ntools can be re-utilized in follow-up projects. It has been demonstrated that a standards-compliant development of\r\nsmall and medium-sized medical software can be carried out by a small team with limited resources in a clinical\r\nsetting. This is of particular relevance as the upcoming revision of the Medical Device Directive is expected to\r\nharmonize and tighten the current legal requirements for all European in-house manufacturers....
Background: Although useful in the emergency treatment of pelvic ring injuries, external fixation is associated with\r\npin tract infections, the patient�s limited mobility and a restricted surgical accessibility to the lower abdomen. In this\r\nstudy, the mechanical stability of a subcutaneous internal anterior fixation (SIAF) system is investigated.\r\nMethods: A standard external fixation and a SIAF system were tested on pairs of Polyoxymethylene testing cylinders\r\nusing a universal testing machine. Each specimen was subjected to a total of 2000 consecutive cyclic loadings at 1 Hz\r\nwith sinusoidal lateral compression/distraction (+/-50 N) and torque (+/- 0.5 Nm) loading alternating every 200 cycles.\r\nTranslational and rotational stiffness were determined at 100, 300, 500, 700 and 900 cycles.\r\nResults: There was no significant difference in translational stiffness between the SIAF and the standard external\r\nfixation when compared at 500 (p = .089), 700 (p = .081), and 900 (p = .266) cycles. Rotational stiffness observed for the\r\nSIAF was about 50 percent higher than the standard external fixation at 300 (p = .005), 500 (p = .020), and 900 (p = .005)\r\ncycles. No loosening or failure of the rod-pin/rod-screw interfaces was seen.\r\nConclusions: In comparison with the standard external fixation system, the tested device for subcutaneous internal\r\nanterior fixation (SIAF) in vitro has similar translational and superior rotational stiffness....
Background: The aim of the survey was to obtain information on the treatment plan preferences, mechanics\r\nand characteristics of temporary anchorage device (TAD) application using a single case presented to orthodontists\r\nin Switzerland.\r\nMethods: A structured questionnaire to be completed by all study participants with case-specific (treatment plan\r\nincluding mechanics and TAD usage) and general questions (general fixed appliance and TAD usage as well as\r\nprofessional, educational and demographic questions) together with an orthodontic borderline case was utilised.\r\nThe case was a female adult with dental Class II/2, deep bite and maxillary anterior crowing, who had been\r\ntreated in childhood with extraction of four premolars and fixed appliance followed by wisdom tooth extraction.\r\nResults: The response rate was 24.4% (108 out of 443). The majority (96.3%, 104) proposed comprehensive\r\ntreatment, while 3.7% (4) planned only alignment of maxillary teeth. 8.3% (9) included a surgical approach in\r\ntheir treatment plan. An additional 0.9% (1) combined the surgical approach with Class II mechanics. 75.1% (81)\r\ndecided on distalization on the maxilla using TADs, 7.4% (8) planned various types of Class II appliances and 3.7%\r\n(4) combined distalization using TADs or headgear with Class II appliances and surgery. Palatal implants were the\r\nmost popular choice (70.6%, 60), followed by mini-screws (22.4%, 19) and mini-plates on the infrazygomatic crests\r\n(7.0%, 6). The preferred site of TAD insertion showed more variation in sagittal than in transversal dimension, and\r\nthe median size of mini-screws used was 10.0-mm long (interquartile range (IQR) 2.3 mm) and 2.0-mm wide\r\n(IQR 0.3 mm).\r\nConclusions: Distalization against palatal implants and then distalization against mini-screws were the most popular\r\ntreatment plans. Preferred site for TAD insertion varied depending on type and size but varied more widely in\r\nthe sagittal than in the transversal dimension...
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