Study on in vitro performance verification protocol for left ventricular assist device.

OBJECTIVE: In vitro performance verification of ventricular assist devices using a mock circulatory loop is a prominent step to guarantee the system responses and the device performance and safety before the in vivo tests and ultimately clinical trials. METHODS: In this article, we performed a comprehensive literature research to establish a verification matrix consisting of 12 test cases, defined by a set of physiological parameters which are commonly used to characterize a physiological condition. The clinical hemodynamic indicators for defining successful mechanical support were used as the acceptance criteria. A mock circulatory loop was customized to simulate the test cases, and a full verification protocol was described in details. An example left ventricular assist device was incorporated in the loop to accomplish a standard ventricular assist device performance verification. RESULT: The test cases based on clinical data with sufficient safety margin represent our understanding in defining the extremes of operation. The mock circulatory loop was capable of generating the test conditions in the verification matrix and reproducing the Frank-Starling law of the native heart. The effect of the left ventricular assist device assistance (characterized by the total systemic flow, mean aortic pressure, and left atrial pressure) was well verified by the proposed protocol and acceptance criteria. CONCLUSION: To date, all left ventricular assist devices made in China have been evaluated according this protocol and some of them have entered the clinical trial stage. We are closely observing the clinical data in order to further improve the performance of the platform and encourage more advances in mechanical circulatory assist devices.

Time Course Changes in Confirmed 'True' VO 2 max After Individualized and Standardized Training.

This study sought to examine time course changes in maximal oxygen consumption (VO 2 max) confirmed with verification testing following 12 weeks of standardized vs. individualized exercise training. Participants (N=39) were randomly allocated to differing exercise intensity prescription groups: ventilatory threshold (individualized) or % heart rate reserve (standardized). At baseline, 4, 8, and 12 weeks, participants completed maximal exercise testing with a verification protocol to confirm 'true VO 2 max.' VO 2 max in the standardized group changed from 24.3±4.6 ml·kg -1 ·min -1 at baseline to 24.7±4.6, 25.9±4.7, and 26.0±4.2 ml·kg -1 ·min -1 at week 4, 8, and 12, respectively, with a significant difference (p<0.05) in VO 2 max at week 8 and 12 compared to baseline. The individualized group had increases in VO 2 max from online 2 9.5±7.5 ml·kg -1 ·min -1 at baseline to 30.6±8.4, 31.4±8.4, and 32.8±8.6 ml·kg -1 ·min -1 at week 4, 8, and 12, respectively. In the individualized group, there were significant differences (p<0.05) in VO 2 max from baseline to week 8 and 12 and a significant increase in VO 2 max from week 8 to 1 online 2 . Although not statistically significant, our preliminary data demonstrates a more rapid and potent improvement in VO 2 max when exercise intensity is individualized. This is the first investigation to employ use of the verification procedure to confirm 'true VO 2 max' changes following exercise training using ventilatory thresholds.

Clinical verification protocol of domestic SPECT and its implementation / 医疗卫生装备

It is the first time to lay down a complete and accurate plan for clinical verification protocol of domestic SPECT. The protocol's application to the first domestic BHP6601 SPECT proves its definitive purpose, reliability and completion. The protocol can meet the requirements of the criterions of China and related department, and thus must be beneficial to the clinical verification and popularization of large-scale nuclear medicine image equipment.