Friday, April 20, 2012
Cardiac ultrasound can be used to show the presence of pulmonary hypertension if there is a tricuspid insufficiency, pulmonary stenosis, or pulmonary insufficiency. Continuous Wave Doppler is used to determine the velocity and pressure gradient of the valvular flow. Pulsed Wave Doppler is not capable of measuring higher flow rates. Pressure gradient indicates the difference between the pumping chamber (the right ventricle in this case) and the receiving chamber (either the right atrium in tricuspid insufficiency or the pulmonary artery in pulmonary stenosis). A pressure gradient of 10-50 mm Hg is considered to mild pulmonary hypertension, 50-80 mm Hg is moderate, and greater than 80 mm Hg is severe.
Radiographs can also be used to show more severe pulmonary hypertension. If the anterior pulmonary arteries are larger than the veins on the lateral views, pulmonary hypertension is present. On the VD or DV views, the caudal pulmonary arteries will be larger than the veins.
There seems to be some confusion about treatment of pulmonary hypertension. Some recent lectures have unintentionally given the idea that all cases must be treated and that Viagra is the treatment. First, show that pulmonary hypertension is present. Then, identify and treat the cause of the hypertension.
If heartworm disease is present, treat the heartworm disease. If pneumonia is present, treat the pneumonia, etc.
If pulmonary valve stenosis is present, mild cases (PG of 10-50 mm Hg) are not treated. The patient will probably live a full life without symptoms or need for treatment. In moderate to severe cases, ballon valvuloplasty can be done to partially relieve the stenosis.
Pulmonary hypertension is a secondary problem with mitral insufficiency or mitral stenosis because blood backs up to the lungs. The right ventricle must pump against the increased resistance of the mitral insufficiency. The presence of a tricuspid insufficiency allows us to use Continuous Wave Doppler to estimate the pressure of the right ventricle. Normal pressure in the right ventricle is 20 mm Hg and a pressure of 30 mm Hg or higher is considered to represent pulmonary hypertension. Usually, treatment of the mitral insufficiency will also treat the pulmonary hypertension.
Viagra is usually only used in the last 30 days of the patient's life when end stage disease results in uncontrollable pleural effusion. This can be seen in , end stage heart disease (severe mitral insufficiency, tricuspid insufficiency, pulmonary stenosis, pulmonary insufficiency, aortic stenosis, aortic insufficiency), pulmonary fibrosis, chronic fungal pneumonia, neoplasia, or other infiltrative diseases.
Saturday, February 18, 2012
Next, look for a machine that is user friendly. How can you tell if it will be easier to use? Look at the keyboard. Are the buttons, knobs, or toggles clearly labeled as to the function they control? With some machines, each button, knob, or toggle may have multiple functions. Ask to see the owner’s manual. If there is one booklet, the machine is probably user friendly. If there are 3 or 5 separate booklets, it is a very complicated machine. In my opinion, the complicated, “big box” ultrasound machine is capable of making multiple adjustments to give the absolute best quality image, but the operator must know and use all of the available button, knobs, and toggles to get that image. This type of machine may cost $80,000 to $350,000 or more and is a necessity for a radiologist or cardiologist. It is perfectly acceptable if this is the kind of machine you want. In my opinion, this is more ultrasound machine than a general practitioner needs. In my opinion, a general practitioner needs a machine that is user friendly and can be quickly learned and put to use in the practice. In my experience, when machines or procedures are difficult or tedious, most people will not use the machine or do the procedures. Take the time (2-3 days) to study the owner’s manual and learn how to use the machine you buy.
Fourth, what kind of training is available to you? An ultrasound machine is worthless if you do not know how to use it. Some ultrasound sales companies include training in the cost of the machine. It is not free. You are paying for it whether you use it or not. You will probably have to pay for your own travel and lodging to get to the training. You may consider separating the cost of training from the cast of the machine, especially if you are financing the cost of the machine. Some ultrasound companies offer training for a fee.
Saturday, February 11, 2012
Tuesday, February 7, 2012
2 Large Packages Black Cherry Jello (the darkest color available to disguise the objects you add) + 2 packets of plain Knox gelatin (for firmness)
Disolve Jello and gelatin in 3 cups of hot water (not boiling)
Pour mixture into a 1 quart ziploc freezer bag. Add 12 prunes. Eliminate as much air as possible as you seal the bag. Lay the bag flat in the refrigerator and allow the gelatin to set. It will become quite firm. Remove from the refrigerator, use ultrasound gel, and practice.
Sometimes I add small balloons filled with milk or water for cystocentesis practice.
Many people figured out how to use Jello to make phantoms. I adapted my recipe from Knox Blox. How many of you are old enough to remember those? I think, more recently, they're called Jigglers.