The Valve Mounting Procedure describes the method for moulding silicone device holder rings and mounting devices for the ViVitro Labs Pulse Duplicator, HiCycle, and RWT. This method allows the device to be mounted and removed without altering or damaging the device. For information on how to purchase pre-made, custom device holders, please contact firstname.lastname@example.org.
The Bellows Change Procedure describes the method for maintaining and changing bellows for the ViVitro Labs HiCycle. This method helps optimize durability testing by preventing and minimizing equipment downtime. If the recommendations in the wear prevention section are adhered to, the latest generation of bellows has been shown to last over 200 million cycles. This means the act of replacing bellows will be seldom conducted.
ViVitro Labs offers service agreements and contract routine onsite maintenance services. However, if you prefer to perform this and other regular maintenance on your HiCycle internally, the Bellows Change Procedure describes the best methods to do so. (more…)
Use this link to download a copy of the Operations and Maintenance Instructions for Carolina Medical Electromagnetic Flowmeter Model 501 & 501D supplied with ViVitro Labs equipment.
Whether you’re getting unexpected results or new to the system and want to confirm you’re calibrating the flow measurement in ViViTest correctly, there is a quick, easy check to verify the operation of the flow measuring system used with the ViVitro Labs pulse duplicator.
This step can be done after calibration or in place of performing a calibration. Set-up the pulse duplicator as it would be for flow calibration (section 6.3 of the pulse duplicator user manual). Remember to remove all air from the VIA and bubbles from ventricle chamber. There needs to be a direct connection between the SuperPump and the test fluid, with no compliant elements in the flow path.
Figure 1. Pulse duplicator setup for flow calibration in aortic (left) or mitral (right) configuration.
Set the waveform in ViViTest to Sine50. With the system static and ViViTest in Acquire mode, re-zero the sensors. Dial up the stroke volume to your intended test conditions (typically we do this at 75 mL/stroke for 70 BPM). Confirm that the stroke volume on the SuperPump controller matches the stroke volume displayed in ViViTest within ± 0.3 mL. If these values do not match, perform the ViViTest pump calibration as per Appendix E of the Pulse Duplicator User Manual. If these values do match, acquire 10 cycles and save an acq. file. Stop the pump and check that the flow zero hasn’t drifted.
Open this acq. file in the Analyze tab. Display all waveforms and click off the other traces so only the 10 cycles of the flow waveform are displayed. Move the flow markers to isolate the positive and negative portions of the waveform. This can be done several ways, but we do this by marking the positive portion as the closing volume and the negative portion as the leakage volume – this way, the values are displayed right on the user interface, without having to open the data table to see forward flow volume.
For an aortic collection, closing volume is captured between the f2 and f3 markers and leakage volume, between f3 and f4. Ensure the f1 marker stays to the left of f2. See figure 2 below for an example. For a mitral collection, closing volume is between f1 and f2 and leakage volume is between f2 and f3. Ensure the f4 marker stays to the right of f3.
The volume captured by the absolute values of the positive and negative flow portions should match the controller stroke volume within ± 1.0 mL. If they do not, perform the flow calibration again. If these values still don’t match, contact us at email@example.com if you need assistance with troubleshooting.
This FAQ discusses configuration considerations when adapting the ViVitro Pulse Duplicator Model Left Heart flow loop to enable right heart testing.
The ViVitro Pulse Duplicator is composed of the clear acrylic Model Left Heart, SuperPump, Flow Measuring System, and ViViTest data acquisition system. This flexible piece of testing equipment simulates physiological pulsatile flow in the heart using customizable waveform control, peripheral resistance, and compliance while allowing clear device visibility as well as pressure and flow measurement and user-friendly data collection.
Initially the system was designed to mimic conditions of the left side of a heart with the intent of testing prosthetic heart valves. However, since its inception, the ViVitro Pulse Duplicator has also been customized to perform hydrodynamic testing on a variety of novel cardiovascular devices. One common custom use of the Pulse Duplicator system is for Right Heart applications.
Six areas to consider when configuring the standard ViVitro Labs Pulse Duplicator for Right Heart testing:
Figure 1. Standard Peripheral Resistance Controller (left) Pinch valve for resistance control of right heart conditions (right).
Figure 2. Standard heat exchanger (A) with higher efficiency and pressure drop. Low pressure drop heat exchanger (B) with lower efficiency and pressure drop.
Figure 3. Compliance options for pressure waveform control. The aortic root (taller) and Windkessel (shorter) compliance tanks along with other options (not shown) may be necessary.
Figure 4. Controlling fluid level in the atrium chamber to control static pressure.
Figure 5. Model silicone aortic root mounted in the ACM accessory for the ViVitro Labs Pulse Duplicator.
Figure 6. ViViTest software user interface.
Connecting transducers and third party devices to ViVitro equipment is easy and straightforward in ViVitro Labs test equipment. We often get asked about the pressure transducers and flow meter used in our Pulse Duplicator and HiCycle products. They were selected based on performance, accuracy and relative low cost. This allows them to be disposed of, or cleaned, when used with various blood analogues.
As the system gets modified and adopted for non-valve applications, the provided transducers may no longer be ideal. ViViTest software and Data Acquisition System are designed to accommodate any third party pressure and flow measurement tools which are capable of an analog output.
The first step in connecting a third party measurement device is to locate the correct port on the I/O module. Channel 1, 2 and 3 are for pressure signals and channel 5 is for a flow signal. The maximum signal which can be applied is +/-10VDC.
Once they are connected and powered on, start ViViTest on your PC. You will need to select the calibration tab to set the DC offset (if present) and perform a calibration. This calibration wizard will walk you through adjusting the inputs to display correctly in ViViTest and to match the known outputs of our SuperPump AR.
Once the calibration is complete, the pressure and flow data shown in the Acquire tab will be accurate and ready for collection.
If you have any questions about connecting transducers or third party devices to ViVitro equipment, or our products in general please contact firstname.lastname@example.org for more details.
A common question that arises regarding custom use of the Pulse Duplicator system is whether it can be used for Right Heart and Full Heart applications. This PDF by Marshal Kilduff will address this question by noting configurations to the Model Left Heart flow loop to enable right heart testing, as well as how to connect two Pulse Duplicators to allow full heart testing.
One of the key aspects of ISO 17025 Quality Management System (QMS) is the Corrective and Preventive Action process (CAPA). The standard requires that we have a policy (which is part of our Quality Manual) and standard operating procedure (SOP) for handling CAPAs. In addition, a clear designation of the authority for monitoring and implementing CAPAs has to be identified.
In general, any employee can create a CAPA. An important aspect of recording CAPAs is to clearly and concisely describe the issue that has occurred (corrective) or potential issue (preventive). For Management it is critical to nurture a company culture that is oriented to not only point out issues but also come up with constructive and timely solutions. Team work between Management, QA and lab personnel is integral to successful handling of CAPA. Determining root cause of the issue and outlining clear actions is definitely more successful with a team approach. However, usually QA personnel take leadership role in moving CAPA process forward.
The key for a successful CAPA system and the best way to resolve CAPA is having Management support and consistent follow up (and follow up, follow up…) so that issues don’t slip trough the cracks. QA team plays main role providing guidance to both Management team and personnel working on CAPA. Never give up!
ViVitro Labs customers can now lease, rent or purchase cardiovascular test equipment. While renting or leasing test equipment is relatively commonplace in a variety of industries, medical device manufacturers have preferred to purchase test equipment outright. The medical industry is now discovering the benefits of leasing/renting test equipment. These benefits include:
Try before buying
With the variety of solution offerings in the Cardio Vascular Test Equipment market, buyers want to ensure they are purchasing the best equipment for their application. Leasing allows users to test drive a solution and ensure the product will meet their requirements before incurring capital costs.
Free up cash flow
We all know that in running a business cash flow is king. This is nowhere more important that for small medical device start-up firms. In many cases it will be years before entering the market place with a commercially approved device. Maintaining good cash flow can be achieved more easily by potentially leasing or renting large capital cost equipment such as test gear. Development projects frequently change scope and purchased equipment may not be applicable for future projects, tying up valuable capital for long periods of time.
Latest Equipment Offerings
Continuous changes to advanced medical test equipment can make the solution you purchase less capable then the latest model available from production. By leasing or renting your solution the Research and Development team is working with the latest available system. Typically equipment that is returned from a lease or rental agreement completion is modified to incorporate the latest capabilities from the manufacturer. In certain cases, custom modifications can be requested when leasing medical test equipment to achieve maximum results during the lease period.
Let’s not forget that expenditures for test equipment do not end with a purchase. Service and maintenance must be considered when budgeting for such a purchase. With a lease or rental the equipment is maintained and serviced by the manufacturer. This not only reduces budgets but it also reduces potential down time and ensures the equipment will be serviced correctly by authorized and trained individuals using approved components.
People often ask, “Why buy a ViVitro Pulse Duplicator or HiCycle when I could build something myself? How do they compare to equipment built in-house ?” My initial reaction is always similar to that of Dominik Obrist: “It’s more complicated than you think.” Dominik speaks from experience.
“Complicated” is actually short hand for “takes time, requires expertise, and ends up costing more.” Here is my top 10 list of reasons why you should outsource the purchase of Pulse Duplicator and Durability testing equipment instead of doing it yourself:
Lab Manager, MSc.
ViVitro Labs Inc