The Model 917 is ideal for a smaller hospital that needs a Doppler for use in obstetrics as well as a doppler for difficult blood pressure measurements or for vascular screening. The nominal 2 MHz* probe gives depth for big targets, like the fetal heart, and also picks up the relatively large amount of umbilical flow.
An earphone jack for hi-fi headphones is provided because in difficult cases where it is important to know if there is a viable fetus, you will hear much better with big, bulky earphones than with a speaker. The big headphones shut out outside noise and reproduce the low tones associated with the fetal heart movement much better than the small loudspeaker does. Headphones of this type can be purchased from us or obtained locally. Near term, the reflected signals are so big that use of headphones is not necessary.
The 8 MHz* probe emits ultrasound waves that are smaller and therefore reflect off of red blood cells better. These waves do not go deep enough to be useful in obstetrics.
The Model 917 is essentially two different doppler instruments using a common power source and audio amplifier. For sensitivity, each one is as good as any you can find at any price. Only one doppler operates at a time.
Model 917 comes with one obstetrical probe and one 8 MHz. probe in the style of your choice. Most users buy the pencil probe (shown) but the adult flat and infant flat probes are available as a substitute or at extra cost if you require more than one vascular probe.
The instrument shown to the right is Model 811-BL which incorporates a cautery supressor used in surgery for continuous flow monitoring.
The Model 811 Series is our most popular doppler for hospital service. Model 811-B, our most popular by far, is shown on our home page. Many of these units have been in use for over 25 years. These instruments have been modified internally to keep abreast of newer technology, but the "black box" package has remained the same. (blue and white are available)
This design is now offered in a variety of housings, some with lids to contain gel, probes and charger. Most buy it just as shown in the picture, with either the flat probe or the pencil probe shown with Model 810-A. Used extensively in the OR intraoperatively and for lower limb and arm systolic blood pressure measurements post-op and on the ward.
We recommend a nominal 8 MHz frequency. One pencil or flat probe is included
in the price. An extra probe is $100, and we recommend you get one. The reason
is that if there is failure, you will be able to determine whether it is the
probe or the instrument that is at fault. If it is the probe (most commonly) you
have a back-up.
We also make a microsurgery probe with a 2 mm. tip. To preserve the 2mm beam width, you must NOT let gel or fluid build up around the tip. Just a damp surface is best. Smear the gel if necessary.
The Model 801-B, with the appropriate probe (pencil or flat adult/infant), is used for all indirect systolic blood pressure measurements, for diagnosing vascular abnormalities in the limbs, digits, neck and face. No loudspeaker. No output for recorder. Comparable sensitivity to other non-directional dopplers.