Dialysis For Technician PDF

Dialysis For Technician Dr. M.L.Patel Additional Professor Department of Medicine KGMU Lucknow  Outlin  Indications e  Modalities  Apparatus  Access  Complications of dialysis access  Acute complications of dialysis Indications...

Dialysis For Technician Dr. M.L.Patel Additional Professor Department of Medicine KGMU Lucknow  Outlin  Indications e  Modalities  Apparatus  Access  Complications of dialysis access  Acute complications of dialysis Indications  Pericarditis or pleuritis  Progressive uremic encephalopathy or neuropathy ( asterixis, myoclonus, seizures)  Bleeding diathesis  Fluid overload unresponsive to diuretics  Metabolic disturbances refractory to medical therapy (hyperkalemia, metabolic acidosis, hyper- calcemia , hyper- phosphatemia)  Persistent nausea/vomiting, weight loss, or malnutrition  Toxic overdose of a dialyzable drug….Dialysable substance IgG/>>>>IgM Indications for RRT  Acute management of life-threatening complications of AKI:  A: Metabolic acidosis (pH less than 7.1)  E: Electrolytes -- Hyperkalemia (K >6.5 meq/L) or rapidly rising K)  I: Ingestion -- Certain alcohol and drug intoxications  O: Refractory fluid overload  U: Uremia, ie. pericarditis, neuropathy, decline in mental status Goals of Dialysis  Solute clearance  Diffusive transport (based on countercurrent flow of blood and dialysate)  Convective transport (solvent drag with ultrafiltration)  Fluid removal Modalities  Peritoneal dialysis  Intermittent hemodialysis  Hemofiltration  Continuous renal replacement therapy Decision of modality determined by catabolic rate, hemodynamic stability, and whether primary goal is fluid or solute removal  Principles of dialysis  Dialysis = diffusion = passive movement of solutes across a semi- permeable membrane down concentration gradient  Good for small molecules  (Ultra)filtration = convection = solute + fluid removal across semi- permeable membrane down a pressure gradient (solvent drag)  Better for removal of fluid and medium- size molecules Faber. Nursing in Critical Care 2009; 14: 4  Principles of dialysis  Hemodialysis = solute passively diffuses down concentration gradient Dialysate flows countercurrent to blood flow. Urea, creatinine, K move from blood to dialysate Ca and bicarb move from dialysate to blood.  Hemofiltration: uses hydrostatic pressure gradient to induce filtration / convection plasma water + solutes across membrane.  Hemodiafiltration: combination of dialysis and filtration. Miller's Anesthesia, 7th ed. 2009 Foot. Current Anaesthesia and Critical Care 2005; 16:321-329 Hemodialysis Apparatus  Dialyzer (cellulose, substituted cellulose, synthetic noncellulose membranes)  Dialysis solution (dialysate – water must remain free of Al, Cu, chloramine, bacteria, and endotoxin)  Tubing for transport of blood and dialysis solution  Machine to power and mechanically monitor the procedure (includes air monitor, proportioning system, temperature sensor, urea sensor to calculate clearance) Hemodialysis Access  Acute dialysis catheter (vascular catheter, i.e. Quentin catheter)  Cuffed, tunneled dialysis catheter (Permcath)  Arteriovenous graft  Arteriovenous fistula Arteriovenous Fistula  Preferred form of dialysis access  Typically end-to-side vein-to-artery anastamosis  Types  Radiocephalic (first choice)  Brachiocephalic (second choice)  Brachiobasilic (third choice, requires superficialization of basilic vein, i.e. transposition)  Lower extremity fistulae are rare Radiocephalic AVF Brachiocephalic AVF Arteriovenous Graft  Synthetic conduit, usually polytetrafluoroethylene , between an artery and a vein  Either straight or looped  Common sites  Straight forearm : Radial artery to cephalic vein  Looped forearm : brachial artery to cephalic vein  Straight upper arm : brachial artery to axillary vein  Looped upper arm : axillary artery to axillary vein Arteriovenous Graft Tunneled Cuffed Catheters  Dual lumen catheters  Most commonly placed in the internal jugular vein, exiting at the upper, anterior chest  Can also be placed in the femoral vein  Subclavian catheters should be avoided given the risk of subclavian stenosis Cuffed Dialysis Catheter  Dialysis Access : Time to use  Graft  Usually cannulated within weeks  Vectra or flexine grafts can safely be cannulated after ~12 hours  Fistula  Median period of 100 days before cannulation in the U.S. and U.K.  Initial cannulation should be performed with small gauge needles and low blood flow Complications of AVF and AVG  Thrombosis  Infection (10% for AVG, 5% for transposed AVF, 2% for non- transposed AVF)  Seromas  Steal (6% of B-C AVF, 1% of R-C AVF)  Aneurysms and pseudoaneurysms (3% of AVF, 5% of AVG)  Venous hypertension (usually 2/2 central venous stenosis)  Heart failure (Avoid AVFs in pts with severely depressed  LVEF)  Local bleeding Tunnel Cuffed Catheters  Indications  Intermediate-duration vascular access during maturation of AVF or AVG  Expected lifespan on dialysis of < 1 year (due to co-morbidities or on living donor transplant list)  Medical contra-indication to permanent dialysis access (severe heart failure)  Patients who refuse AVF or AVG after explanation of the risks of a catheter  All other dialysis access options have been exhausted Tunnel Cuffed Catheters : Complications  Infection  Risk of bacteremia 2.3 per 1000 catheter days or 20 to 25% over the average duration of use  Dysfunction  Defined as inability to sustain blood flow of >300 mL/min  By this definition, 87% of catheters malfunction in their lifetime  Central venous stenosis  Mortality (may be influenced by selection bias) Tunnel Cuffed Catheters : Bacteremia  Metastatic infections Osteomyelitis, endocarditis, septic arthritis, suppurative thrombophlebitis, or epidural abscess  Risk factors : prolonged duration of usage, previous bacteremia, recent surgery, diabetes mellitus, iron overload, immunosuppression, malnutrition Tunnel Cuffed Catheters : Bacteremia  Clinical manifestations  Fevers or chills in catheter-dependent dialysis patients associated with positive blood cultures in 60 to 80%  Less commonly : hypotension, altered mental status, catheter dysfunction, hypothermia, and acidosis Tunnel Cuffed Catheters : Bacteremia  Empiric Treatment  Vancomycin (load with 15-20 mg/kg and then 500-1000 mg after each HD session) plus either gentamicin (load with 2 mg/kg and then 1 mg/kg after each HD session) or ceftazidime (2 grams after each HD session)  Avoid prolonged use of an aminoglycoside given the risk of ototoxicity with vestibular dysfunction Tunnel Cuffed Catheters : Bacteremia  Duration  Catheter removal and replacement, early resolution of symptoms, blood cultures quickly negative : 2 to 3 weeks  Uncomplicated S. aureus infection : 4 weeks  Metastatic infection or persistently positive blood cultures : minimum 6 weeks  Osteomyelitis : 6 to 8 weeks Acute Complications of Dialysis  Hypotension (25-55%)  Cramps (5-20%)  Nausea and vomiting (5-15%)  Headache (5%)  Chest pain (2-5%)  Back pain (2-5%)  Itching (5%)  Fever and chills (