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, , , , , ,*,代理报关委托书委托报关协议关于审理城镇房屋租赁合同纠纷案件司法解释有关劳务派遣制度设计及对劳务派遣行业的影响分析糖皮质激素在呼吸系统疾病中的合理应用严重脓毒症导致急性肺损伤病人自发利尿现象的观察分析,Renal Replacement Therapy in Perioperative Medicine,ASA refresher courses 2006,.,Renal Replacement Therapy in P,1,Introduction,The kidneys control,- fluid and electrolyte balance,- excretion of metabolic byproducts,- production of hemoglobin,- activation of vitamin D,“Renal replacement therapies (RRT)”,- hemodialysis + its progeny,(peritoneal dialysis, continuous hemofiltration,and continuous hemodiafiltration),.,IntroductionThe kidneys contro,2,What is “Renal Failure”?,Surprisingly, there is no universally accepted definition for renal failure,Renal function is evaluated based on two separate functions,1) formation of concentrated urine,2) excretion of byproducts of protein metabolism,Creatinine clearance + urinary output,- renal function ,.,What is “Renal Failure”?Surpri,3,What is “Renal Failure”?,Significant limitations,- fluctuation with extracellular volume, metabolic rate,- functional reserve fx 50% ,serum creatinine ,- creatinine is actively secreted by nephron,(overestimate GFR),Current criteria for the diagnosis of ARF,- serum creatinine baseline 3 ,- a 75% decrease in GFR,(determined by creatinine clearance),- urinary output of less than 0.3 ml/kg per hour,or anuria for 12 hours,.,What is “Renal Failure”?Signif,4,What are the indications for RRT,.,What are the indications for,5,What are the indications for RRT,.,What are the indications for,6,Processes of Renal Replacement Therapies,RRT uses an artificial kidney to remove fluid (solvent) and substances dissolved in the blood (solute),Several processes are used to produce hemofiltrate, usually in combination,1. Ultrafiltration (),2. Convection (, ),3. Diffusion (),4. Membrane Adsorption,.,Processes of Renal Replacemen,7,Processes of Renal Replacement Therapies,1. Ultrafiltration,2. Convection,- solvent drag,- removal of water and middle sized molecules from the,blood,.,Processes of Renal Replacemen,8,Processes of Renal Replacement Therapies,3. Diffusion - Smaller molecules,(electrolytes, urea, and creatinine),4. Membrane Adsorption - Artificial Membranes (AN69),- This tendency is determined principally by pore size and,surface area,.,Processes of Renal Replacemen,9,Types of RRT,.,Types of RRT .,10,Intermittent RRT,1. Intermittent hemodialysis (IHD),The most efficient method of RRT,Large amounts of fluid can be removed and electrolyte abnormalities can be rapidly corrected over a relatively short period,“Dialysis disequilibrium syndrome (),- osmotic shift ARF 20-30% ,- hemodynamic changes may worsen the pre-existing renal,injury,.,Intermittent RRT 1. Interm,11,Intermittent Renal Replacement Therapy,1. Intermittent hemodialysis (IHD),Arterio-venous fistula or a double lumen central catheter,Blood is pumped into a filter, running countercurrent to,dialysate (ionized water),Blood flow rate (200-400 ml/min),Dialysate flow (approximately 500 ml/min),Filtration rate (between 300 and 2000 ml/hour),Urea clearance (150-250 ml/min),With this high flow and clearance rate, patients only require,3 to 4 hours of dialysis, two or three times a week,.,Intermittent Renal Replacement,12,Intermittent Renal Replacement Therapy,1. Intermittent hemodialysis (IHD),Major complications relate to,- rapid shifts in plasma volume and solute composition,- the angioaccess procedure,- the necessity for anticoagulation,- dialysis membrane incompatibility,(immunologic reactions to dialysis membranes are widely,described),.,Intermittent Renal Replacement,13,Intermittent Renal Replacement Therapy,1. Intermittent hemodialysis (IHD), IHD ,- predialysis or immediately post-dialysis, 24 , ,- fluid resuscitation and electrolyte administration,- succinylcholine ,(patients with CRF tolerate hyperkalemia),- significant renal excretion (pancuronium, vecuronium),- metabolic acidosis - volume of chloride,.,Intermittent Renal Replacement,14,Intermittent Renal Replacement Therapy,1. Intermittent hemodialysis (IHD), ,- frequently hypovolemic, hypokalemic, and alkalotic,- vasodilatory anesthetic agents,- fluid resuscitation ,- massive resuscitation (particularly with red cells) leading to,hypervolemia and hyperkalemia, dialysis should be,arranged for the patient in the immediate postoperative,period,.,Intermittent Renal Replacement,15,Intermittent Renal Replacement Therapy,1. Intermittent hemodialysis (IHD),Uremic patients,- hyperkalemia, hyperphosphatemia, metabolic acidosis,and increase the risk of hemodynamic instability,- hypermagesemia potentiates the effects of neuromuscular,blockers,- volume overload (hypertension and CHF),- delayed gastric emptying,- platelet dysfunction,.,Intermittent Renal Replacement,16,Intermittent Renal Replacement Therapy,2. Peritoneal dialysis (PD),Installation of hypertonic dialysate into the peritoneal cavity,(peritoneum acting as a semipermeable membrane),Fluid remains in place for 30-40 minutes and then is drained (an exchange),Simple and cost effective,Poor solute clearance, poor uremic control, risk of peritoneal infection, and mechanical obstruction of pulmonary and cardiovascular systems,.,Intermittent Renal Replacement,17,Intermittent Renal Replacement Therapy,2. Peritoneal dialysis (PD),CAPD (continuous ambulatory peritoneal dialysis),- the original version of PD, developed in the 1970s,- patients undergo four manual exchanges per day,(three daytime exchanges and an overnight exchange),Cycler dialysis,- 10 ,- a machine is attached to the peritoneal dialysis catheter,that fills and drains the abdomen three or more times at,night,-during the day the patient may perform one or more,manual exchanges in order to achieve an adequate dialysis,dose,.,Intermittent Renal Replacement,18,Intermittent Renal Replacement Therapy,2. Peritoneal dialysis (PD),Tidal Peritoneal Dialysis (TPD),- repeated installation of small tidal volumes of dialysate,using an automatic cycler machine,- the dialysate is neither fully drained nor replenished with,each exchange,(more contact with the dialysate and peritoneal membrane),- improved patient comfort,Less metabolically clean than those undergoing HD fluid and electrolyte problems,As PD fluid impedes pulmonary mechanics, it should be either partially or fully drained preoperatively,.,Intermittent Renal Replacement,19,Continuous Renal Replacement Therapies,Developed to overcome the problem of hemodialysis in hemodynamically unstable patients in the ICU,Aggressive removal of solute without major osmolar shifts,Removes fluid and solute slowly over a 24 hour period using the principals of diffusion, ultrafiltraton, convection and membrane adsorption,.,Continuous Renal Replacement T,20,Continuous Renal Replacement Therapies,Techniques,1. Slow continuous hemofiltration (SCUF),2. Continuous veno-venous hemofiltration (CVVH),High volume ultrafiltration (HVUF),3. Continuous veno-venous hemodialysis (CVVHD),4. Continuous veno-venous hemodiafiltration (CVVHDF),.,Continuous Renal Replacement T,21,Continuous Renal Replacement Therapies,Techniques,1. SCUF (slow continuous ultrafiltration),- used purely for fluid overload (CHF),2. CVVH (continuous venovenous hemofiltration),- removal of fluid and middle sized molecules,- as the ultrafiltration rate is high, replacement electrolyte,solution is required to maintain hemodynamic stability,HVUF (high volume ultrafiltration),- modification of CVVH,- large amounts of fluid are removed and replaced per hour,as a means of cleaning (remove inflammatory cytokines),.,Continuous Renal Replacement T,22,Continuous Renal Replacement Therapies,Techniques,3. CVVHD (continuous veno-venous hemodialysis),- continuous diffusive dialysis,(the dialysate is driven in a direction countercurrent to the,blood),- effective solute clearance (mostly small molecules),4. CVVHDF (continuous venous venous hemodiafiltration),- the most popular method of dialysis in ICU,- both small and middle molecules are cleared,- both dialysate and replacement fluids are required,- in the majority of patients, the most efficient approach to,CRRT,.,Continuous Renal Replacement T,23,Continuous Renal Replacement Therapies,Advantages of CRRT in critical illness,1. Suitable for use in hemodynamically unstable patients,2. Precise volume control, which is immediately adaptable to,changing circumstances,3. Very effective control of uremia, hypophosphatemia and,hyperkalemia,4. Rapid control of metabolic acidosis,5. Improved nutritional support (full protein diet),6. Available 24 hours a day with minimal training,7. Safer for patients with brain injuries and cardiovascular,disorders,8.May have an effect as an adjuvant therapy in sepsis,9.Probable advantage in terms of renal recovery,.,Continuous Renal Replacement T,24,Continuous Renal Replacement Therapies,Anticoagulation (prevent clotting of the filter) - heparin,Heparin has a number of potential drawbacks,1. The risk of bleeding,2. Requires the presence of antithrombin III, which is often,deficient in the ICU population,3. Heparin may cause thrombocytopenia (HIT syndrome),Agents that have been used instead of heparin,1. PGE1 and PGI2 (anti-platelet effects),2. Citrate, which binds calcium and inhibits the coagulation,cascade and is metabolized to bicarbonate in the liver,3. Low molecular weight heparins,4. Hirudin,5. Argatriban,.,Continuous Renal Replacement T,25,Sustained low-efficiency dialysis - extended daily dialysis,Provide hemodynamically stable,Blood flow (200 ml/min), dialysate rates (300 ml/min or less),The dialysis cycle is 6 to 12 hours,Less labor intensive for the ICU nursing staff, and less prone to unexpected problems (disconnections, filter clots),No current evidence of outcome benefit,.,Sustained low-efficiency dialy,26,RRT in the ICU,Investigation of RRT in the ICU has focused on two independent questions,1) the effectiveness of RRT to remove fluid and solute,2) the utility of RRT as an adjunct therapy in sepsis,Schiffl et al.,- 160 hemodynamically stable critically ill patients,- randomized to daily or alternative day dialysis,- daily dialysis (markedly better solute clearance, and lower,volume removal),- shorter duration of renal failure and lower mortality,- main priority of CRRT in critical illness should be solute,rather than fluid removal,.,RRT in the ICUInvestigation of,27,RRT in the ICU,Ronco et al.,- examined 3 differing doses of CVVH in ARF,- the patient group receiving 35 ml/kg/hour had significantly,improved survival compared to those receiving 20,ml/kg/hour,- Increasing the ultrafiltration rate further led to no additional,benefit,- again, improved outcome was associated with improved,solute clearance,.,RRT in the ICURonco et al.,28,RRT in the ICU,Aggressive hemofiltration at rates of up to 6 liters per hour improve outcome in sepsis by removal of proinflammatory cytokines,- reductions in pressor requirements in vasoplegic patients,- potential benefit in necrotitis fulminans,- circulating cytokine levels are inversely related to outcome,in sepsis,- reinfusion of hemofiltrate into animal models causes a,syndrome indistinguishable from septic shock,Although conventional CVVH improves cardiovascular status, clearance of cytokines is poor,High volume ultrafiltration reversed endotoxic shock,.,RRT in the ICUAggressive hemof,29,RRT in the ICU,Cole et al.,- 11 patients randomized to 8 hours HVUF (6 L/hour) versus,8 hours of CVVH (1.5 L/hour),- Significantly greater reduction in norepinephrine,requirements,- Greater reduction in central anaphylactoxins in the HVUF,- However, it is unclear whether this benefit was from,greater adsorption into the membrane,- Outcome benefit has not been demonstrated in controlled,trials,RRT cannot currently be recommended as a routine adjunct to conventional therapy in sepsis,.,RRT in the ICUCole et al. .,30,Conclusion,Anesthesiologists routinely care for patients at varying intervals of the renal replacement paradigm,- patients in acute renal failure undergoing emergency,surgery,- patients established on hemodialysis,- patients undergoing arterio-venous fistula or peritoneal,dialysis insertion etc,Consequently, an understanding of the indications for, mechanisms of, and side effects of renal replacement therapy is of significant value,.,ConclusionAnesthesiologists ro,31,
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