Dialysis Water

Dialysis water

During hemo-dialysis about 500 ml (range 50-800 ml) of dialysate flows through the dialyer (The plastic casing that contains dialysis membrane and which partitions blood on one side and dialysate on the other).

Water treatment is an essential requisite for safe dialysis.

In a 4 to 5 hrs session about 120 to 150 liters of water thus comes into contact with blood.

A very small impurity in this water thus can get magnified and produce serious consequences in the renal failure patient.

If dialysis water is unfit, it results in recurrent fever, poor health and nutrition of patient, electrolyte abnormalities etc. High aluminium levels can produce brain disorder called dementia and aluminium related bone disease. High chlorine levels can cause severe reactions.

Water treatment is done for ensuring safe dialysis water.

If ground or municipal supply provides hard water it is softened by machine.

Particulate matter is removed by filters consisting of pebbles, sand and other materials first so that large particles are removed, small particles than are removed by microfilters which can remove 5-micron size particles.

Chlorine is removed by adsorption on to carbon particles. It should be present in water before it is treated but removed during water treatment.

Excessive salts are measured as TDS (total dissolved solids) expressed as parts per million or ppm in short.Both cations and anions measured and TDS is equal to about 100 X total ions expressed as milliequivalents. It is usually 0.5 to 1 times the conductivity value.

Bacteria and their products produce harmful substances. These need to be removed and water prevented from letting them grow again by regular maintenance of the pipes and drainage system.

To produce water of sufficiently good quality, various criteria have been laid by different countries. AAMI dialysis criteria is one such criteria. In these acceptable levels of various chemicals and other impurities are mentioned.

Good quality dialysis water reduces morbidity, mortality, and complications in dialysis. It results in better overall health and quality of life for the patient.

Treatment of Hypertension

Treatment of Hypertension

Why should hypertension be treated ?

The following are the benefits of treating hypertension:-

  • 50 % reduction in risk of heart failure
  • 30-40% reduction of risk of strokes of brain
  • 20-30 % reduction in risk of heart attacks.

The benefit occurs in all age groups including elderly. If a cause has been found (as happens in very few cases) treatment of underlying cause is useful e.g. treating kidney disease, removing adrenal tumours, stopping steroids, analgesics, contraceptive pills, certain anti depressants etc.

In the majority of cases, no cause is found. In these, we suggest non-pharmacologic ways as well as medicines to lower blood pressure.

Non-pharmacological methods may reduce blood pressure by 5- 10 mm on their own. These include

Reduction of weight if overweight

Reduction of salt in diet (avoid pickles, salted foods, preserved foods). Do not take salt substitutes if there is associated kidney disease.

Dash diet ( dietary approaches to stop hypertension diet ). Increase vegetables, whole grain cereals, low fat, low sugar and sweets, more fruits, fish and chicken if you are a non vegetarian

Increase physical activity, both physical aerobic activity and relaxation exercises may help

Stop or cut down on alcohol and smoking

Learn about Hypertension.

Pharmacological methods may reduce blood pressure

2 or more drugs are required if BP is >20/10 above the normal range. More medicines and higher doses are needed if blood pressure is due to kidney disease. These drugs may cause side effects and hence prescriptions are tailor made to suit particular requirements of the patient.

The drugs include

Diuretics : – which increase salt and water excretion in the body. These work only if salt is cut down in the diet.

ACE- inhibitors and ARB’s : -These are a class of medicines which protects against ill effects of high BP on kidneys, heart and brain. However, treatment is complicated and always should be under the guidance of a competent physician. These drugs are known to cause fetal malformations. Inform your doctor if you are pregnant or are planning to have a child,

Calcium Channel Blockers :- Very useful and often used class of drugs. Some times these may cause feet to swell otherwise these are well tolerated.

Betablockers:- These reduce heart rate and blood pressure. This is useful in reducing stress on the heart. However, these may cause serious worsening in asthma and may aggravate prostate symptoms, and may cause impotence.

Centrally acting and alfa blockers:- These are also useful in controlling BP. Some of these may cause or worsen depression.

Dialysis Access

Dialysis Access

Blood flows on one side of membrane while dialysate flows on the other side. To ensure effective dialysis a high blood flow is required for taking blood from the body to the dialysis machine. The blood flow required is about 5ml/kg body weight /min. Usually 250 ml to as much as 500-600 ml if tolerated.

The way to achieve this is through creation of dialysis access. This may be temporary or permanent.

A temporary access is made in those patients who will require dialysis for a few days to few weeks as in acute kidney injury ( also called earlier as ARF or acute renal failure), while awaiting creation of a permanent access.

Temporary access is obtained by inserting a tube in neck veins (Int Jugular Vein) usually on right but sometimes on left side. It is uncommon nowadays to use subclavian (behind collar bone ) or upper thigh veins. The advantage of this is that it is ready to use immediately however it often gets infected and may cause clot formation in the vein in which it is placed. It should be used for less than 2 weeks and never handled by patient. Sudden dislodgement may cause bleeding. In case long term dialysis is required and AV fistula( read further on to know about AVF) is not yet ready a permanent dialysis catheter which is useful for a few months is a far better though costly choice.

The method of choice is creation of arterio-venous fistula (AVF). It is usually made in the wrist but if blood vessels are small or thrombosed it is at times made in arm near elbow. This requires surgery usuaally under local aneasthesia. The failure rates are higher if done by inexperienced surgeons (1 in 2 to 1 in 4 AVFs may fail.)

It takes 2 to 3 months to mature and hence should be made much before the need of dialysis arises. It should be checked to see that it is working. If there is stoppage of flow early treatment may make it work again but if delayed another AVF creation is required.

If injured rapid bleeding may occur. So protect these from injuries. Do not allow these to be used for drugs and samples other than in dialysis room by dialysis personnel.

A good AVF is a life line for patients. Get it made early & keep it functional !!

Hypertension

Hypertension

The heart pumps blood so that it can reach various parts of the body and supply these parts with oxygen and nutrients. The pressure generated by the heart forces the blood to go from the heart to various organs and return from there to be sent again. There is about 5 liters of blood in average adult and heart pumps about 70 ml in each heart beat. The force generated by heart results in pressure which can be measured.

Hypertension is said to occur when the recorded blood pressure is higher than expected for the particular age. Children have lower BP, it gradually rises to adult levels and continues to increase with age in most cases. BP is measured by sphygmomanometer which was earlier mercury based but are now aneroid or electronic. BP is measured as Systolic ( higher value of the two ) and diastolic (lower reading) and written as systolic/diastolic BP in mm of Hg. e.g. 120/80 mm Hg.

Blood pressure at birth is about 70 to 85 /30 to 45 , at 5 yrs 90-110/50-66 , at 10 yr 100-120/60-80. In adults blood pressure is diagnosed when it is usually more than 140/90 mm Hg.

Causes of high blood pressure.

In most cases, there is no apparent cause. Suspicion usually falls on genetic disease, high salt intake, higher weight etc. in younger patient sometimes a cause is detected. It is often due to kidney disease, hormonal disorders, blood vessel diseases or diseases disturbing immunity. It can at times be caused by drugs like steroids and analgesics.

Symptoms of high Blood pressure

Most patients have no symptoms due to high blood pressure. It is only the measurement of blood pressure which reveals the diagnosis. Some patients with high blood pressure may have headaches, dizziness, throbbing or at times shortness of breath. If blood pressure rises suddenly to very high levels it may cause emergencies. These may include vision loss, renal failure, alteration in consciousness ( drowsiness or unconsciousness), or heart failure (manifested as breathlessness worse on lying down or activity)

Clinically it is diagnosed by BP measurement, usually on more than one occasion while a person is sitting with back supported. 2 or 3 readings may be taken and the lower readings are usually more accurate. If in doubt multiple readings can be taken while the person is continuing his activities (ABPM or ambulatory BP monitoring). Eyes are checked as blood vessels can be seen in the retina, ECG and X Ray Chest may show heart enlargement.

Laboratory tests:-

Lab tests are done to find the cause of high blood pressure if any, its effects on various organ systems and complications. The usual tests done are Blood counts, urine routine examination, Blood Urea, S Creatinine, S electrolytes, Blood Sugar, Lipid profile in blood, ECG, X Ray of chest and Ultrasonography of abdomen. In special cases hormones may be measured or Doppler Ultrasound studies are done to check blood flow and vessels in different areas.

Complications of high blood pressure:-

Complications arise if the blood pressure is very high or it has been present for  a long time. Not all persons with high BP get complications. Some of the complications are :

  • Strokes (paralytic attacks due to bleeding in the brain or reduced blood supply to part of the brain)
  • Increased likelyhood of heart attacks.
  • Heart failure (not stoppage of heart beat or cardiac arrest ) but inability of heart to meet bodily demands. This is diagnosed by swelling of feet, breathlessness at night after sleeping for 2-3 hours, fatigue etc.
  • Chronic renal disease resulting in renal failure if allowed to go unchecked for long periods.
  • Decreased blood supply to other organs due to thickening of blood vessel walls and narrowing of their internal lumen (athersosclerosis of aorta, limb vessels, vessels supplying brain, kidneys, heart, eyes etc.)

Coming up soon :

Treatment of high blood pressure

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Dialysis

Dialysis

When the kidneys fail to maintain the body in a healthy state, the condition is called chronic renal failure. In advanced stages of chronic renal failiure, symptoms arise. These are called uremic symptoms and may consist of one or more of the following:-

Weakness, decreased appetite, nausea, vomiting, hiccups, breathlessness, swelling of the body, decreased amount of urine etc. Later on a person may develop fits or increasing drowsiness, unconsciousness, extreme weakness, muscle paralysis etc. Initially these symptoms are mild but later on they do not allow a person to live a normal life and still later they will kill a person unless treated.

The process of taking over of failed kidney functions by treatment is called Renal Replacement Therapy (RRT). This mainly comprises of Dialysis and Renal Transplant.

Dialysis is the process through which the accumulated waste products are removed. It also removes extra water salt, potassium, acid, phosphorus and molecules of middle size.  Thus it attempts to return the body to a healthy state.

Dialysis is mainly of two types:- Hemodialysis and Peritoneal dialysis.

Hemodialysis

In this a membrane called dialysis membrane is used as a filter. It is folded many times over to increase its area to about .5 sq meters to 2 sq meters (for children and adults of various sizes). This membrane allows only small molecules to move from one side to the other.

Blood flows on one side of the membrane and dial sate fluid flows on the other. The dialysate fluid is produced in the dialysis machine by diluting commercial concentrates. The composition of the dialysate is similar to Blood without cells, proteins, fats and other larger molecules.

Smaller molecules present in high concentration in blood and dialysate move across because of difference in concentration (called electrochemical gradient) from a higher concentration to lower concentration. Pressure can be applied across the membrane to create pressure to push water and salt across as well.