Exam 2: Renal and Heme Flashcards
Voluntary avoidance of these foods is a subtle sign of renal disease:
High protein
Voluntary avoidance of these foods is a subtle sign of renal disease:
High protein
Normal GFR:
125 ml/min
Blood flow to the kidney:
25% of CO
95% to cortex, 5% to medulla
Conditions requiring dialysis:
GFR 10-15% of normal Hyperkalemia Fluid overload Oliguria Severe acidosis Metabolic encephalopathy Pericarditis Coagulopathy Refractory GI symptoms Drug toxicity
Vessels used for AV fistula:
Cephalic vein
Radial artery
Pre-op timing of dialysis:
Day of or day before surgery
Expected weight drop post-dialysis:
2-4%
Post-dialysis serum K+ should be:
Drugs cleared by dialysis:
Low molecular weight
Water-soluble
Non-protein-bound
S/s of uremic encephalopathy:
Asterixis Myoclonus Lethargy Confusion Seizures Coma
Describe disequilibrium syndrome:
Transient CNS disturbance after rapid ↓ in ECF osmolarity (relative to ICF) due to dialysis
Dementia-like
Associated with rapid change from acidotic to alkalotic
Typical hgb in renal failure:
6-8 g/dL
Effect of renal failure on bones:
↓ VitD production leads to ↓ Ca++ absorption
↓ Ca++ leads to ↑ PTH
Bone marrow replaced with fibrous tissue
More prone to fracture
Factors causing rightward shift in renal failure pts:
Metabolic acidosis
↑ 2,3-DPG
Factors causing impaired platelet function in renal failure:
↓ platelet factor 3
↓ adhesiveness/aggregation
Normal GFR:
125 ml/min
Blood flow to the kidney:
25% of CO
95% to cortex, 5% to medulla
Conditions requiring dialysis:
GFR 10-15% of normal Hyperkalemia Fluid overload Oliguria Severe acidosis Metabolic encephalopathy Pericarditis Coagulopathy Refractory GI symptoms Drug toxicity
Vessels used for AV fistula:
Cephalic vein
Radial artery
Pre-op timing of dialysis:
Day of or day before surgery
Expected weight drop post-dialysis:
2-4%
Post-dialysis serum K+ should be:
K
Drugs cleared by dialysis:
Low molecular weight
Water-soluble
Non-protein-bound
S/s of uremic encephalopathy:
Asterixis Myoclonus Lethargy Confusion Seizures Coma
Describe disequilibrium syndrome:
Transient CNS disturbance after rapid ↓ in ECF osmolarity (relative to ICF) due to dialysis
Dementia-like
Associated with rapid change from acidotic to alkalotic
Typical hgb in renal failure:
6-8 g/dL
Effect of renal failure on bones:
↓ VitD production leads to ↓ Ca++ absorption
↓ Ca++ leads to ↑ PTH
Bone marrow replaced with fibrous tissue
More prone to fracture
Factors causing rightward shift in renal failure pts:
Metabolic acidosis
↑ 2,3-DPG
Factors causing impaired platelet function in renal failure:
↓ platelet factor 3
↓ adhesiveness/aggregation
Factors causing impaired platelet function in renal failure:
↓ platelet factor 3
↓ adhesiveness/aggregation
Hematologic problems in renal failure:
Impaired platelets
Impaired WBC function
Defective vWF
Hypocomplementemia d/t dialysis
CV changes in renal failure:
↑ CO compensating for anemia HTN --> Na+ retention, RAAS activation LV hypertrophy CHF w/ pulmonary edema when compensatory limits reached Ca++ deposition into conduction system/valves Arrthymias Uremic pericarditis Accelerated CAD/PVD
Fluids to use in renal patients:
NO LR: K+ in it
NO D5: most are diabetic
Use NS - small bag - microdrip
Pulmonary changes in renal failure:
Minute ventilation increased to compensate for metabolic acidosis
Interstitial edema –> widened alveolar/arterial O2 gradiant
Butterfly wings on CXR 2/2 inc capillary permeability
Ventilatory considerations in renal failure:
Don’t use NO
Use 100% FiO2
Endocrine changes in renal failure:
Insulin resistance/poor glucose tolerance
Hyperparathyroidism
Abnormal lipid metabolism/accelerated atherosclerosis
Increased circulating hormones/proteins
GI/liver changes in renal failure:
GI hemorrhage (10-30%)
Anorexia
N/V
Hypersecretion of gastric acid, delayed emptying
Anesthesia considerations with GI/liver changes:
RSI
Hold off on transfusions unless critical to minimize antigens (transplant potential)
Examples of drugs contraindicated in renal failure:
Gallamine
Phenobarbital
LMWH
Succinylcholine
NMB of choice in renal failure:
High dose roc; give it 60-90 seconds
Lab tests for patients in renal failure:
Chemistry panel Osmolarity BUN/Cr + GFR Creatinine clearance (24 hr) Urine SG/osmo
Normal BUN:
10-20 mg/dL
BUN indicative of ↓ GFR:
50 mg/dL+
Non-renal causes of abnormal BUN:
High protein diet
GI bleed
Febrile illness
Lag time between ∆ GFR and ↑ Cr:
8-17 hr
Source of Cr:
Skeletal muscle
Cr levels in elderly:
Tend to stay normal d/t ↓ muscle mass and GFR both
Best indicator test for renal function:
24-hr creatinine clearance
Interpreting CrCl:
Normal 100-120 ml/min ↓ Renal Reserve 60-100 ml/min Mild Renal Impairment 40-60 ml/min Moderate Insufficiency 25-40 ml/min Renal Failure
Electrolyte derangements in renal failure:
Hyponatremia Hyperkalemia Metabolic acidosis Hypermagnesemia Hypocalcemia Hypoalbuminemia Hyperglycemia
Five treatments for hyperkalemia:
Calcium gluconate 10% Sodium bicarbonate Glucose + insulin Dialysis Ion exchange resin
Describe calcium gluconate for hyperkalemia:
Ca gluconate 10% 10-20ml IV
Antagonizes K+ effects on cardiac muscle
Immediate onset, brief duration
Avoid with digoxin
Describe sodium bicarb for hyperkalemia:
50-100 mEq IV
Shifts K+ into cells
Prompt onset but short duration
Can cause Na+ overload
Describe glucose + insulin for hyperkalemia:
50ml of D50 + 10U regular insulin Shifts K+ into cells Prompt onset, 4-6 hr duration Best option for urgent case! Can cause glucose derangement
Describe dialysis for hyperkalemia:
Removes K+ from body
Immediate effect
Need vascular access, though
Describe ion exchange resins for hyperkalemia:
Removes K+ from body
Onset 1-2 hours
Can cause Na+ overload
Normal Hct:
40-54% male
38-47% female
Normal Hgb:
13.5-18 g/dL male
12-16 g/dL female
Normal WBC:
5,000-10,000
Transfusion indications for renal patients:
Hgb
Normal plt:
150,000 - 400,000
Regional anesthesia usually not done on renal patients due to:
Coagulopathies
Peripheral neuropathies
Treatment for coagulopathy in the renal patient:
Desmopressin 0.3 - 0.4 mg/kg IV over 30 min
Cyro 10 units IV over 30 min
CaO2 =
Hgb * 1.39 * SaO2 + (PaO2 * 0.003)
Factors that increase oxyhemoglobin affinity:
Alkalosis ↓ PCO2 ↓ temperature ↓ 2,3-DPG Carboxy-/methemoglobin Abnormal hgb
Factors that decrease oxyhemoglobin affinity:
CADET, face right! ↑ CO2 Acidosis ↑ 2,3-DPG ↑ temperature
Major compensatory mechanism for anemia until
Increase in 2,3-DPG which causes a right shift and decreased affinity/increased O2 delivery
Other compensation for anemia:
↓ SVR ↑ HR/CO ↑ plasma volume Redistribution of blood flow to organs with higher extraction ratio ↑ extraction ratio in vascular beds
Anemia risk factors:
GI bleeding Heavy menses Cancers (esp. bone) Chronic infections Nutritional deficiency
Factors to consider in anemic patients when deciding what Hbg/Hct is acceptable:
Duration of the anemia Etiology Fluid volume status Urgency of surgery Anticipated blood loss Co-existing disease
