CNN cheat sheet

Each kidney contains roughly 1 million nephrons; glomerular filtration produces about 180 L/day of ultrafiltrate, of which more than 99% is reabsorbed.

Normal GFR is approximately 125 mL/min/1.73 m2; CKD GFR categories are G1 ≥90, G2 60-89, G3a 45-59, G3b 30-44, G4 15-29, and G5 <15.

Albuminuria categories are A1 <30 mg/g, A2 30-300 mg/g, and A3 >300 mg/g of urine creatinine.

Renin is secreted by juxtaglomerular cells in response to reduced renal perfusion, reduced sodium delivery, or beta-adrenergic stimulation; angiotensin II raises vascular resistance and aldosterone promotes sodium and water retention.

ADH increases collecting duct water permeability through aquaporin-2 channels, concentrating the urine.

Endocrine kidney functions are erythropoietin production, activation of 25-hydroxyvitamin D to 1,25-dihydroxyvitamin D by proximal tubule 1-alpha-hydroxylase, and renin secretion.

The kidney excretes hydrogen ions and regenerates bicarbonate; advanced CKD produces metabolic acidosis that increases protein catabolism and bone demineralization.

CKD-mineral and bone disorder: falling GFR raises phosphate and FGF23, lowers 1,25-vitamin D and calcium, and drives secondary hyperparathyroidism.

KDIGO AKI definition: creatinine rise ≥0.3 mg/dL within 48 hours, or ≥1.5 times baseline within 7 days, or urine output <0.5 mL/kg/hour for 6 hours.

Cockcroft-Gault creatinine clearance (mL/min) = (140 − age) × weight in kg ÷ (72 × serum creatinine), multiplied by 0.85 for women; used for drug dosing.

The 2021 CKD-EPI creatinine equation is race-free; add a cystatin C-based eGFR when creatinine is distorted by very low or high muscle mass, amputation, or heavy protein intake.

BUN-to-creatinine ratio >20:1 suggests prerenal azotemia or upper GI bleeding; a ratio of 10-20:1 suggests intrinsic renal disease.

Fractional excretion of sodium <1% indicates prerenal physiology and >2% suggests intrinsic tubular injury; values are unreliable with diuretics, CKD, or contrast.

Anion gap = Na − (Cl + HCO3); normal is about 8-12 mEq/L, and an elevated gap occurs with uremic acids, ketoacidosis, lactic acidosis, or toxins.

Adequacy targets for thrice-weekly hemodialysis are single-pool Kt/V ≥1.2 and urea reduction ratio ≥65%.

Hyperkalemia ECG sequence: peaked T waves, then PR prolongation with loss of P waves, then QRS widening, sine wave pattern, and cardiac arrest.

Corrected sodium for hyperglycemia: add 1.6 mEq/L to the measured sodium for every 100 mg/dL glucose above 100 mg/dL.

The peritoneal equilibration test classifies membrane transport (high, high-average, low-average, low) and guides dwell time and fill volume prescription.

Access surveillance combines physical examination, static and dynamic venous pressures, recirculation studies, and measured urea clearance.

Hemodialysis clears solute by diffusion down a concentration gradient; ultrafiltration removes plasma water by hydrostatic or osmotic pressure gradient.

Typical hemodialysis prescription: blood flow 300-500 mL/min, dialysate flow 500-800 mL/min, 3-4 hours per session, three sessions weekly.

Ultrafiltration rate generally should not exceed 13 mL/kg/hour to limit intradialytic hypotension and myocardial stress.

Dialysis disequilibrium syndrome results from rapid urea clearance creating an osmotic gradient into brain cells; prevent with lower blood flow and a shorter first session.

Peritonitis is diagnosed when effluent is cloudy with >100 WBC/mm3 and >50% neutrophils; treat with intraperitoneal antibiotics per protocol.

AV fistula maturation takes about 6-8 weeks; the rule of sixes is flow >600 mL/min, diameter >0.6 cm, and depth <0.6 cm.

Rejection types: hyperacute (minutes to hours, preformed antibodies), acute (days to months, cellular or antibody-mediated), and chronic (months to years, fibrosis).

Maintenance immunosuppression typically combines a calcineurin inhibitor, an antimetabolite such as mycophenolate, and corticosteroids.

Air embolism management: stop the blood pump, clamp the line, place the patient left lateral Trendelenburg, and give 100% oxygen.

Phosphate binders must be taken with meals to bind dietary phosphorus in the gut; taken between meals they are largely ineffective.

A common fluid allowance is 500-1000 mL/day plus the previous day's urine output; interdialytic weight gain above 2-3 kg signals excess intake.

Sodium restriction is typically under 2 g/day; salt substitutes contain potassium chloride and are hazardous in advanced CKD.

Potassium restriction is usually 2-3 g/day, with leaching of high-potassium vegetables and avoidance of potassium-containing salt substitutes.

AV access self-monitoring: daily palpation of the thrill and auscultation of the bruit; report loss of thrill, pain, redness, or bleeding immediately.

Teach-back requires the patient to restate instructions in their own words, confirming comprehension better than asking whether they understand.

Home peritoneal dialysis teaching covers sterile exchange technique, dry exit-site care, and immediate reporting of cloudy effluent, abdominal pain, or fever.

Immunosuppressant adherence is critical; missed doses, herbal products, and grapefruit (CYP3A4 inhibition) alter tacrolimus levels.

CMS Conditions for Coverage are federal minimum health and safety requirements for ESRD facilities covering infection control, water and dialysate quality, and patient rights.

AAMI standards require testing dialysis water for chlorine and chloramine before each shift and after carbon filter changes to prevent hemolysis.

Catheter-based dialysis carries the highest bloodstream infection risk; fistula-first initiatives and catheter reduction are national quality goals.

Hand hygiene is required before patient contact, before aseptic tasks, after body fluid exposure, after patient contact, and after touching patient surroundings.

Common dialysis quality indicators include Kt/V ≥1.2, urea reduction ratio ≥65%, hemoglobin 10-11 g/dL, phosphorus control, and catheter prevalence under 10%.

Medication safety includes reconciliation each shift, review for nephrotoxins, and dose adjustment of renally cleared drugs.

Sharps safety: containers at point of use, no recapping, and immediate reporting with postexposure prophylaxis after a needlestick.

The interdisciplinary team (nephrologist, nurse, dietitian, social worker, technician) reviews care plans regularly as required by the Conditions for Coverage.