Dialysis Introduction Type And Principle Of Peritoneal Dialysis

Introduction:

Dialysis is the artificial process of getting rid of waste (diffusion) and unwanted water (ultrafiltration) from the blood. This process is naturally done by kidneys. Some people, however, may have failed or damaged kidneys which cannot carry out the function properly - they may need dialysis. In other words, dialysis is the artificial replacement for lost kidney function . Dialysis may be used for people who have become ill and have acute kidney failure (temporary loss of kidney function), or for fairly stable patients who have permanently lost kidney function (stage 5 chronic kidney disease). Dialysis  need  when people develop end stage kidney failure --usually by the time people lose about 85 to 90 percent of kidney function.

Types Of Dialysis:

There are two main types of dialysis.

1. Hemodialysis:

The blood circulates outside the body of the patient , it goes through a machine that has special filters. The blood comes out of the patient through a catheter (a flexible tube) that is inserted into the vein. The filters do what the kidney's do; they filter out the waste products from the blood. The filtered blood then returns to the patient via another catheter.

Patients need to be prepared for hemodialysis: A blood vessel, usually in the arm, needs to be enlarged. . The enlarged vein makes the insertion of the catheters possible. US researchers have developed a new way of growing blood vessels using patients' own skin cells to seed the growth of tissue and have tested it in dialysis patients with end stage kidney disease.

Hemodialysis usually lasts about 3 to 4 hours each week. The duration of each session depends on how well the patient's kidneys work, and how much fluid weight the patient has gained between treatments. Hemodialysis is either done in a special dialysis center in a hospital.

2. Peritoneal Dialysis :

A sterile (dialysate) solution rich in minerals and glucose is run through a tube into the peritoneal cavity, the abdominal body cavity around the intestine, where the peritoneal membrane acts as a semi-permeable membrane.

The abdomen is the area between the chest and hips , it contains the stomach, small intestine, large intestine, liver, gall bladder, pancreas and spleen. Peritoneal dialysis uses the natural filtering ability of the peritoneum ,the internal lining of the abdomen. In other words, peritoneal dialysis uses the lining of the abdomen as a filter of waste products from the blood.

The dialysate is left there for some time so that it can absorb waste products. Then it is drained out through a tube and discarded. This exchange, or cycle, is generally repeated several times during the day - with an automated system it is often done overnight. The elimination of unwanted water (ultrafiltration) occurs through osmosis - as the dialysis solution has a high concentration of glucose, it results in osmotic pressure which causes the fluid to move from the blood into the dialysate. Consequently, a larger quantity of fluid is drained than introduced.

Although peritoneal dialysis is not as efficient as hemodialysis, it is carried out for longer periods. The net effect in terms of total waste product and salt and water removal is about the same as hemodialysis.

Peritoneal dialysis is done at home by the patient; by a willing and motivated patient. It gives the patient a greater amount of freedom and independence because he/she does not have to come in to the clinic at multiple times each week. It can also be done while traveling with a minimum of specialized equipment. Peritoneal dialysis is said to 'save lives and save money'.

Before having peritoneal dialysis, the patient needs to have a small surgical procedure to insert a catheter into the abdomen. This is kept closed off, except when fluid is being introduced or taken out of the abdomen.

There are two principal types of peritoneal dialysis:

1. Continuous ambulatory peritoneal dialysis (CAPD) :

This requires no machinery and can be done by the patient or a caregiver. The dialysate is left in the abdomen for up to eight hours. It is then replaced with a fresh solution straight away. This happens every day, about four to five times per day.

2. Continuous cyclic peritoneal dialysis (CCPD) :

A machine does the dialysis fluid exchanges. It is generally done during the night while the patient sleeps. This needs to be done every night. Each session lasts from ten to twelve hours. After spending the night attached to the machine, the majority of people keep fluid inside their abdomen during the day. Some patients may require another exchange during the day. A study found that a significant number of patients prefer "dialysis while patient sleep" treatment.

Burn Introduction Management Of Minor And Major Burn Prevention

Introduction:

A burn is an injury caused by thermal, chemical, electrical, or radiation energy. A scald is a burn caused by contact with a hot liquid or steam but the term 'burn' is often used to include scalds.Most burns heal without any problems but complete healing in terms of cosmetic outcome is often dependent on appropriate care, especially within the first few days after the burn. Most simple burns can be managed in primary care but complex burns and all major burns want a specialist and skilled multidisciplinary approach. 

Management of minor burn:

• Clean burns with soap and water, or a dilute water-based disinfectant to remove loose skin.
• All blisters should be deroofed to help assess depth of burn .
• Nonadhesive dressing, with gauze padding is usually effective, but biological dressings are better, especially for children.
• Dressings should be examined at 48 hours to reassess the burn, including depth.
• Dressings on superficial partial thickness burns can be changed after 3-5 days in the absence of infection.
• If infection occurs, daily wound inspection and dressing change is required

Management of major burn:

Prompt irrigation with running cool tap water for 20 minutes provides appropriate cooling. Very cold water should be avoided (causes vasoconstriction and worsens tissue ischaemia and local oedema). Chemical burns may need longer periods of irrigation.

• Dressings help relieve pain and keep the area clean but avoid circumferential wrapping as can cause constriction.
• All patients with facial burns or burns in an enclosed environment should be assessed by an anaesthetist for early intubation.
• For full thickness circumferential burns, escharotomy may be required to avoid respiratory distress or reduced circulation to the limbs as a result of constriction.
• Transfer to a burns centre or other appropriate care centre as indicated.

Immediate management of Burn:

Airway:
The airway above the glottis is very susceptible to obstruction because of exposure to heat. The clinical presentation of inhalation injury may be subtle and often does not appear in the first 24 hours.

Clinical indications of inhalation injury include:

• Singeing of the eyebrows and around the nose.
• Carbon deposits and acute inflammatory changes in the oropharynx.
• Carbon-particles seen in sputum.
• Hoarseness.
• History of impaired awareness, e.g. alcohol or head injury, and/or confinement in a burning environment.
• Explosion, with burns to head and torso.
• Carboxyhaemoglobin level greater than 10% if the patient is involved in a fire.

Management of acute inhalation injury:

• Early management may require endotracheal intubation and mechanical ventilation.
• Transfer to a burn centre.
• Stridor is an indication for immediate endotracheal intubation.
• Circumferential burns of the neck may lead to swelling of the tissues around the airway and so require early intubation.

Stop the burning process:

• Remove all clothing - adherent synthetic clothing and tar should be actively cooled with water, and left for formal debridement.
• Dry chemical powders should be carefully brushed from the wound.
• Rinse the involved body surface areas with copious amounts of tap water. Cool the burn with tepid water for up to 20 minutes. Great care is required as cooling may cause hypothermia, especially in children and those with extensive burns - and may worsen shock.
• Remove constricting clothing and jewellery before covering the patient with warm, clean and dry linens to prevent hypothermia.

Breathing:

• Arterial blood gas determinations should be obtained as a baseline but arterial PO2 does not reliably predict CO poisoning. Therefore, baseline carboxyhaemoglobin levels should be obtained, and 100% oxygen should be administered.
• Elevation of the head and chest by 20 to 30 degrees reduces neck and chest wall oedema. If a full-thickness burn of the chest wall leads to severe restriction of the chest wall motion, chest wall escharotomy may be required.
• Carbon monoxide (CO) poisoning: has a much greater affinity than oxygen for haemoglobin and so displaces oxygen.
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• Higher CO levels may result in headache and nausea, confusion, coma and death.
• CO dissociates very slowly but this is increased by breathing high-flow oxygen via a non-rebreathing mask.

Intravenous access and fluid replacement:

• Large-calibre intravenous lines must be established immediately in a peripheral vein.
• Any adult with burns affecting more than 15% of the body surface area or a child with more than 10% of body surface area affected requires fluid resuscitation.
• Resuscitation fluids required in the first 24 hours from the time of injury 

Adults:

• 3-4 ml (3 ml in superficial or partial thickness burns, 4 ml in full thickness burns or those with associated inhalation injury) of Hartmann's solution/kg body weight/% total body surface area.
• Half of this calculated volume is given in the first eight hours and the other half is given over the following 16 hours.

Children:

• Resuscitation fluid as above plus maintenance (0.45% saline with 5% dextrose) which should be titrated against nasogastric feeds or oral intake:
• 100 ml/kg for first 10 kg body weight plus 50 ml/kg for the next 10 kg body weight plus 20 ml/kg for each extra kg.
• Ensure adequate analgesia: strong opiates should be used.
• Prevent hypothermia.

Complication :

• Respiratory distress from smoke inhalation or a severe chest burn
• Fluid loss, hypovolaemia and shock
• Infection
• Increased metabolic rate leading to acute weight loss
• Increased plasma viscosity and thrombosis
• Vascular insufficiency and distal ischaemia from a circumferential burn of limb or digit
• Muscle damage from an electrical burn may be severe even with minimal skin injury; rhabdomyolysis may cause renal failure
• Haemoglobinuria and renal damage

Prevention:

There are many important aspects of prevention of burns, including:

• Safety in the workplace.
• Safety in the home, including regularly checking smoke alarms.
• Good parenting to protect children.
• Care of the frail elderly and the socially isolated.
• Prevention of sunburn: appropriate duration and timing of sunbathing, sun protection creams, and regulation of tanning booths.