Vascular Occluders

HSP OCCLUDER DIMENSIONS

CLEANING AND STERILIZATION

TESTING PROCEDURES

OPERATION INSTRUCTIONS

HSP vascular occluders are constructed entirely of 100% medical grade silicone rubber. They are soft, flexible and have a smooth outer finish for ease in maintaining cleanliness. They are completely autoclavable for thorough sterilization.

Silicone rubber, noted for it's high degree of physiological compatibility, makes HSP occluders the ideal choice for prolonged implantations such as chronic blood flow studies, or similar application.

HSP vascular occluders are available in standard lumen sizes ranging from 1.5mm to 24mm. Lumen sizes of 10mm to 24mm are available in a heavy duty model as well.

The Heavy Duty Occluders are designed for greater resistance to rupture and are recommended for use in more rugged applications. They feature a thicker cuff and diaphragm to withstand greater back pressures, well beyond the normal physiological range. As with the standard models, they maintain a high degree of sensitivity and produce consistently accurate results.

These devices are for veterinary use only

Silicone Cleaning & Sterilization

Cleaning: 

HSP silicone devices may be cleaned in a solution of hot water and mild soap. Synthetic detergents and oil based soaps should NOT be used, as they may be absorbed and subsequently leached out in transported fluids. If it is necessary to use a brush, only a very soft bristled one should be used. Rinse thoroughly in purified (distilled) water, taking care to flush the lumen of the tubing. Autoclave before the interior becomes dry. It is important that moisture be present on the inside of the tubes to avoid air locks during autoclaving.

Sterilization: 

It is critical that a sterilization protocol be established for your specific product configuration.

Steam: Medical grade silicone tubing is able to withstand all common steam autoclave sterilization cycles without adverse effects to the tubing. Autoclave cycles should be qualified by the user to their product configuration prior to sterilization.
Wrap in a non-linting material or place in a clean tray. Autoclave by one of the flowing:
• High-speed instrument Sterilizer: 10 minutes at 132 decrees Celsius and 30psi.
• Standard gravity Sterilizer: 30 minutes at 121 degrees Celsius and 15psi.

Ethylene Oxide, (EtO): the tubing is sterilized by normal EtO cycles that have been qualified by the user: aeration times must also be set by the user in accordance with the product configuration. This method is not recommended unless you know how long it takes to complete the out gassing of the residual EtO and other byproducts for the system you use.

Dry Heat: Any usual dry heat sterilization method qualified by the user may also be used to sterilize the silicone tubing. 

Radiation: Silicone has been shown to withstand gamma radiation sterilization with the usual exposure levels qualified by the user. Some physical properties may be slightly changed as a result of this form of sterilization. Effects that have sometimes been seen include: tensile strength remains essentially unchanged; minimal but measurable increase seen in durometer and tensile modulus at 200% elongation: tear strength and elongation may be slightly decreased. Exposure at 2.5 megarads produces minimal physical property changes, even at 200% elongation.

Vascular Occluder Test Procedures

To insure accurate results, read these procedures carefully before placing this device into service.

OPERATIONAL PRINCIPAL

The occluder cuff is wrapped around the exposed vessel and secured in place using suture material passed through the eyelets. Air or liquid is then injected into the actuating tube by syringe, inflating the diaphragm and compressing the vessel into occlusion.

MATERIALS REQUIRED FOR OPERATION

For sizes VO-1.5N through VO-6, use a 20 gauge blunted needle and a 10 cc syringe
For sizes VO-8 through VO-24 and VO-10HD through VO-14HD use a 16 gauge blunted needle and a 20 cc syringe
For sizes VO16HD through VO24HD use a 14 gauge blunted needle and a 20 cc syringe

Caution: We do not recommend implanting occluders without first testing them. See Test Procedure below
Caution: Do not exert excessive pressure in the diaphragm as bursting may result. Use only enough pressure to achieve the desired degree of occlusion.
Caution: Do not inflate unsutured occluders as damage or bursting may result.
 

TESTING PROCEDURE PRIOR TO IMPLANTATION

1. Secure the cuff ends together by tying suture material through the eyelets of the occluder before inflating.

2. Insert the proper size blunted syringe needle into the occluder’s actuating tube.

3. Inject just enough air or liquid into the tubing to inflate the occluder’s cuff to full occlusion.
   CAUTION: DO NOT OVERINFLATE THE DIAPHRAGM AS BURSTING MAY RESULT

4. Hold pressure for 30 seconds while observing for possible leaks.

5. Repeat the procedure 4 to 5 times to relax the diaphragm, particularly if the occluder has not been used recently. 

CALIBRATION OF THE OCCLUDER:

Carefully observe and note the air pressure or liquid volume required for varying degrees of occlusion. The same degree of occlusion may be expected after implantation.
FOR GREATER ACCURACY: calibrate this device in conjunction with a pressure gauge, flow meter, or a simulated flow system. 

STERILIZATION:

This device should be thoroughly cleaned immediately following each use to remove all organic residues.
This device is designed to be sterilized by autoclave or by appropriate cold sterilization methods. Cleaning Instructions

REPAIR OF DAMAGED OCCLUDERS:

Some repairs may be possible depending on the severity of the damage. Contact us for further information and repair services we offer.

We will be happy to answer any questions you may have concerning this device and it’s intended uses to insure customer satisfaction with our products.

Instruction For The Safe Operation of Vascular Occluders

Important: Before implantation, operate the occluder in accordance with the instructions under Testing Procedures listed above.

1. To avoid unintentional constriction, select the occluder size that provides a slightly loose fit around the subject vessel.

2. Wrap the occluder cuff around the exposed vessel and secure it in place using suture material passed through the eyelets and tied securely.

3. Exteriorize the actuating tube through a convenient incision.

4. When used in conjunction with a flow transducer, be sure to position the occluder distally (down stream) from the transducer. If positioned upstream, the vessel will collapse during occlusion, resulting in loss of contact with the transducer’s electrodes or crystals.

5. Occlusion may be determined in a chronic implantation by any of the following methods:

   a. Obliteration of phasic flow patterns displayed by the vessel under study. This is the recommended method for accurately determining zero-flow baseline in small vessels.

   b. Noting the amount of air pressure or liquid volume injected, according to the previous calibration, see Testing Procedure*.

   c. Monitoring of inflation by injecting radiopaque fluid instead of water and viewing the action fluoroscopically.

SUGGESTED ACTUATING MEDIAS FOR VASCULAR OCCLUDERS:

The occluder may be activated by either pneumatic or hydraulic methods. Satisfactory results can be expected by injecting air, inert gas, or various liquids into the actuating tube. Some researchers prefer air because of it’s simplicity, availability, and easy of pressure control. Others prefer water or saline solution, especially for occlusions of longer duration (up to one hour). As a precaution, sterile normal saline solution or sterile distilled water are recommended for use with this device incase fluid is accidentally injected into the animal under study. For procedures requiring occlusion times in excess of one hour, sterile glycerin has been used successfully by researchers due to the fact that glycerin does not transpire through the silicone rubber, it does not evaporate, and it is generally biocompatible.

DURATION OF OCCLUSION FOR VASCULAR OCCLUDERS:

Vascular occluders, when used with water or saline solution perform well for brief occlusions. Stable, long-term occlusion cannot be maintained with water due to it’s tendency to transpire through silicone rubber. Short term occlusion of up to approximately one hour may be maintained successfully using water or saline solution if pressure is applied slightly in excess of what is required to achieve full occlusion. For longer occlusion times, we recommend monitoring the degree of occlusion using any of the methods described in step 5 above, as well as selecting a liquid such as glycerin as the actuating fluid. Glycerin done not transpire or evaporate easily through silicone rubber; nor will it cause damage to the device.

For veterinary use only