Monday, June 20, 2011

STANDARD OF CARE ; ACUTE HEART FAILURE

Continuing in our Monday series, I would like to discuss the standard of care expected when a patient has acute heart failure. This is to allow the lay public to know what is and what is not reasonable, so that they do not misunderstand what the doctor is trying to do.
Acute heart failure, unfortunately is quite common. Heart failure is defined as the inability of the heart to maintain an adequate circulation, to meet the body's metabolic demands. In short, the heart cannot maintain adequate cardiac output, to circulate enough blood for the body to use. When this happens, the patient usually presents with acute breathlessness, and begins to sweat profusely, cold sweat, Incessant coughing is also a symptom, as well as rapid heart beat or irregular heart beat. By nature of the definition, acute means that it comes on rapidly over days or even hours and minutes, as oppose to chronic ambulatory heart failure which may take days, or weeks to evolve. Of course patients with chronic heart failure could also suddenly become acute.
Keeping to the issue of acute heart failure, making the diagnosis is usually fairly easy. The patient or relatives tells the doctor that he suddenly notice that he is short of breath, can no longer talk in full sentences, seems to be sweating cold sweat, and he keeps coughing and the heart feels very fast. The physical examination by the doctor will reveal that there is tachycardia, cold sweat, and also signs of water in the lungs, on listening to the lungs.
These signs and symptoms are easy to explain. As the heart decompensates ( for whatever reasons that we should come to later ), it cannot generate enough output, and so the circulation slows down. The organs begin to tell the brain, that they are not receiving enough oxygen and nutrition, so the brain will respond. Initially by having the heart pump faster, hoping that a faster rate will mean more blood flow. This works for minutes and then the heart cannot cope, and tells the brain, this first response is not sustainable and is harmful. So the brain initiates the second response, which is to cut down all the circulation to the not so useful organs of the body, like the skin. When the circulation to the skin shuts down ( to conserve blood flow so that blood flow can go to more vital organs like the brain, the heart, the kidneys and the liver ), the skin begins to cool down and sweat cold sweat. The skin at the extremities, may also become bluish or dusky in colour. If that is still inadequate to maintain a central circulation, the heart pump being so inefficient, then blood begins to well up in the lungs, as the forward pumping action of the heart begins to get less and less efficient. In circulation terms, the lungs are the organs just before the heart, so that when the heart is unable to pump, the blood can not circulate forward, so it gets dam backwards, almost like a drain that cannot flow out to empty. When the blood dams into the lungs, the air sacs in the lungs, which should contain air, now begins to well up with water and gets heavy, as water is heavier then air. So there is now, increase work of respiration. The patient notice this as breathlessness or dyspnea. On listening to the lungs, we can hear fluid in the lungs.
Once you reach a doctor, he / she should be able to make this diagnosis. Sometimes, in the initial stages, when the signs are not so obvious, there may be some delay in diagnosis.
For the doctor, the challenge may be to know why? What has cause the heart to fail suddenly? In the older age group, above 40 years of age, acute heart attacks must be excluded. Sometimes a heart attack can happen without chest pains, or sometimes with so much breathing distress, the chest pains is forgotten. An ECG done and some blood test for cardiac enzymes, should be able to help make the diagnosis. Sometimes, patients can be so overloaded with fluids that the heart cannot cope. This may be due to IV fluids given too aggressively by the attending physician, not realising that the patient's heart cannot take it, or more often, this can happen with end stage renal failure. Too high a blood pressure can also be a cause of acute heart failure. There are some heart muscle diseases that can cause acute on chronic heart failure. Certain viruses can sometimes affect the heart muscle to cause it to fail, so we hear of a flu-like illness followed by acute heart failure. Sometimes, lung infections, or other serious infection can push an elder patient into heart failure.
In an emergency situation, the attending physician ( all acute heart failures should be attended to, as far as possible, in a hospital, as things can turn bad suddenly ) should perform the basic blood tests, looking at the kidney function, blood count and cardiac enzymes, do an ECG and CXRay. These should suffice in the immediate emergency context. There is always time for the echocardiogram to be done, when the patient is more stable and better.
Often, patient may have to be monitored in the intensive care, as a failure of the heart is a serious matter, and can result in death. Oxygen therapy by mask or nasal prong, is mandatory. The first priority in management, is to get the extra fluids out or the lungs. This will alleviate the acute distress, cut down the panic ( which stresses the heart more ), and make the circulation better. We can usually achieve good diuresis ( passing urine ), with IV diuretics like frusemide. making the patient calm and restful also helps alot. We sometimes achieve this with a small guarded dose of IV morphine. Once the patient calms down, and begins to pour out urine, by the litres literally, he will improve over minutes and hours. In patients with chronic renal failure, this may take a longtime, and sometimes, we need to use the dialysis machine to extract out the extra fluid, so as to off-load the heart. There are certain drugs that can also offload the heart like ACE-I or ARBs, or the good old, nitrates, and calcium channel blockers. When I am meet a severe heart failure, I am one of the few, who like to use a small, carefully monitored, dose of IV sodium nitroprusside. I find that it takes away the strain on the heart very effectively and quickly.
You can almost know that you are getting out of the acute heart crisis, when the hands and feet warm up, the colour returns, and the urine is pouring. Soon the patient can talk to you in full sentences, and he calms down.
If the investigations carried out suggest a heart attack as the cause, then the management should be as with a heart attack, complicated by heart failure ( this usually mean a big heart attack and the prognosis is not as good. Mortality can be 50% ).
Once things are stable, management then becomes management of what cause the heart attack. You have now reverted the patient back to his status before whatever trigger this heart failure happened. Control of poor controlled hypertension is important. Treatment for chronic renal failure is important. Viral infections usually recover, sometimes, leaving behind chronic heart condition and chronic heart failure.
Generally, if you have acute heart failure once, you can have it again, so great care must be taken in the long term. Chronic heart failure will form the basis for another chapter.
As least now you all know what to expect, should someone suffer from acute heart failure.

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