Renal AKI & CKD Flashcards
What is Acute Kidney Injury (AKI)?
The deterioration of renal function over hours to days.
-Dec GFR, so not excreting nitrogenous substances and wastes
-Accumulation of Creatinine and urea in blood
-Dec Urine production
-ATN is most common cause in surgical patients.
-Can be prerenal (Hypoperfusion, obstructive uropathy)
-Mortality < 10% unless in critical illness or MSOF
What are exogenous nephrotoxins?
-Antibiotics (additive effect with other factors)
-Anesthetic agents (Enflurane, Keep Sevo to under 2 MAC hours)
-NSAIDs
-Chemotherapeutic agents (additive effect with other factors)
-Contrast
Who is at increased risk of AKI from Radiocontrast Dye?
-Threat to patients with diabetic nephropathy, renal vasoconstriction and renal insufficiency
-May take 24-48 hours to develop and peak at 3-5 days
What are endogenous nephrotoxins?
-Inc Calcium
-Uric acid
-Myoglobin (Rhabdo)
-Hemoglobin(hemolysis)
-Bilirubin
-Paraproteins
What is Prerenal Azotemia?
High levels of nitrogen compounds such as Urea, Creatinine, etc.
-Reversible if underlying cause is corrected
-Elderly are susceptible due to hypovolemia and renovascular disease
-Inc risk occurs with CHF, Liver dysfunction, and Septic Shock
-May need invasive monitoring to assess intravascular status
What are the causes of Prerenal Acute Renal Failure (decreased RBF)?
Absolute Decreases:
-Acute hemorrhage
-GI fluid loss
-Trauma
-Surgery
-Burns
Low Output Syndromes:
-Renal artery stenosis
-Relative decrease
-Sepsis
-Hepatic failure
-Allergic reaction
Describe Renal Azotemia?
Occurs when the functional unit of the kidney is injured.
-Categorized according to site of injury
-Renal tubules -> ischemia and nephrotoxins
-Can reverse if underlying cause is corrected.
-Irreversible if ischemia is severe or prolonged.
-Acute interstitial nephritis (allergic drug rxn)
What are the etiologies of Renal Acute Renal Failure?
Acute glomerulonephritis
Vasculitis
Interstitial nephritis (drug allergy, infiltrative diseases)
What are the causes of Acute Tubular Necrosis?
Ischemia
Nephrotoxic drugs (aminoglycosides, nonsteroidal anti-inflammatory drugs)
Solvents (carbon tetrachloride, ethylene glycol)
Heavy metals (mercury, cisplatin)
Radiographic contrast dyes
Myoglobinuria
Intratubular crystals (uric acid, oxalate)
What are the causes of Post Renal Acute Renal Failure?
Urinary outflow tracts obstructed:
-Prostatic hypertrophy or cancer of prostate or cervix
-Bladder carcinoma
-Clot retention or nephrolithiasis
Needs quick diagnosis: Potential for recovery inversely related to duration of obstruction
Treatment: Percutaneous Nephrostomy
What are risk factors for Acute Renal Failure (ARF)?
-Co-existing renal dz
-CHF
-Advanced age
-Symptomatic CV disease
-Major operative procedures (CPB, AAA repair)
-Sepsis
-Multi-organ system failure
-Iatrogenic: inadequate fluid volume replacement, delayed tx of sepsis, nephrotoxic drugs or dyes
What are risk factors for Perioperative Renal Failure?
Pre-existing Renal insufficiency
Shock
High-risk Surgical Procedures
Nephrotoxin Use
What are examples of pre-existing renal insufficiency that increases risk for periop renal failure?
Congestive heart failure
Diabetic nephropathy
Hypertensive nephropathy
Liver failure
Pregnancy-induced hypertension
What are high-risk surgical procedures that increase risk for periop renal failure?
Renal vascularization
Aortic cross-clamping
Cardiopulmonary bypass
Urologic surgery
Transplantation
Trauma
What are Nephrotoxins that increase risk for periop renal failure?
Aminoglycoside antibiotics
Radiocontrast dyes
Nonsteroidal anti-inflammatory drugs
What are the Neuro complications of ARF?
Confusion
Asterixis
Somnolence
Seizures
What are the CV complications of ARF?
Systemic HTN
CHF
Pulmonary Edema
Cardiac Dysrhythmias
May have dilutional anemia
Potential for CV Collapse
What are the GI complications of ARF?
Anorexia
Nausea
Vomiting
Ileus
GI Bleeding
What are the S/Sx of ARF?
Generalized Malaise ->
Volume Overload (Dyspnea, edema, HTN) -> Lethargic, Nauseated, confused -> Pulmonary edema, hypoxia, hyperkalemia, acidosis -> Encephalopathy (coma, seizures, death)
By the time of symptom onset, significant kidney injury is occurring
What is the anesthetic management for ARF?
-Fluid Resuscitation: Colloids or crystalloids (NS) acceptable. Keep MAP > 80 mmHg
-Vasopressors: concern with increased renal vasoconstriction
-Dopamine: not supported by literature to treat/prevent ARF. Do have Dopamine receptors in the nephron. Fenoldopam is better (D1 agonist)
-Mannitol: Improves renal outcomes
-Invasive monitoring: BP and frequent blood gases
-Only life saving surgery
Which drugs do you increase the interval in the presence of renal failure?
Acetaminophen
Acetylsalicyclic Acid
Which drugs do you decrease the dose of in the presence of renal failure?
Codeine
Fentanyl
Ketorolac
Meperidine
Methadone
Morphine
What do you do to the dose of Al/Remi/Sufentanil in the presence of renal failure?
No change in dose (? is this right?)
What is Chronic Renal Failure?
Progressive, irreversible deterioration of renal function
-Result of a wide variety of diseases. #1 Diabetes #2 HTN
-Manifests as overall inability of kidney to excrete waste products, regulate fluid and electrolyte balance and secrete hormones
What are the causes of Chronic Kidney Disease?
-Glomerulopathies
-Tubulointerstitial Disease
-Hereditary Diseases
-Systemic Hypertension
-Renal Vascular Disease
-Obstructive uropathy
-HIV
What are Glomerulopathies that cause CKD?
-Diabetes Mellitus
-Systemic Lupus Erythematosus
-Primary glomerular disease
-Focal glomerulosclerosis
-Membranoproliferative glomerulonephritis
-Membranous nephropathy
-Immunoglobulin A nephropathy
-Amyloidosis
-Postinfective glomerulonephritis
-Wegener’s granulomatosis
What are the Tubulointerstitial diseases that cause CKD?
Analgesic nephropathy
Reflux nephropathy with pyelonephritis
Myeloma kidney
Sarcoidosis
What are the hereditary diseases that cause CKD?
Polycystic kidney disease
Alport’s syndrome
Medullary cystic disease
What electrolyte imbalances are associated with CKD?
Hyperkalemia
Hypermagnesemia
Hyperphosphatemia
Hypocalcemia
Metabolic Acidosis.
What are the manifestations of CKD?
-Unpredictable intravascular fluid volume status
-Anemia
-Uremic coagulopathy (Inc bleeding time & plt dysfunction)
-Neurologic changes (autonomic dysfunction, encephalopathy, peripheral neuropathy)
-CV Changes (CHF, Dyslipidemia, Systemic HTN)
-Renal osteodystrophy
-Pruritus
What are the effects of Anemia on the cardiac system?
Heart increases CO in response to anemia
-Increases myocardial demand. Increases risk for CAD.
-Right shift of the Oxy-Hgb Dissociation curve
Tx:
-Base anemia on Hgb rather than Hct and tx with Erythropoietin preop if anemic
How do you treat Chronic Renal Insufficiency?
-Aggressive tx of underlying cause (DM or HTN)
-Transplant or Dialysis
What are the pre-op concerns for a patient with Chronic Renal Insufficiency?
-Concomitant drug therapy
-Clinical manifestations of disease
-Glucose management
-Antihypertensive therapy continued
-Dialysis in the 24 hours preceding surgery
-Serum K+ < 5.5 mEq/L (may have to use succ for RSI: patients are at risk for delayed bowel emptying)
How much does Succinylcholine increase potassium?
By 0.5 - 1 mEq/L
What is the induction sequence for a patient with Chronic Renal Insufficiency?
-Possible RSI (delayed gastric emptying)
-Slow induction: Labile VS (respond as if hypovolemic)
-Positive Pressure ventilation affects venous return, and will impact blood volume and blood pressure
-Succ and K+ level
Which induction agents are terminated by renal excretion?
Partially:
-Barbiturates
Which muscle relaxants are terminated by renal excretion?
Gallamine, Metocurine
Partially:
-Pancuronium
-Vecuronium
Which cholinesterase inhibitors are terminated by renal excretion?
Partially:
-Neostigmine
-Edrophonium
Which cardiovascular drugs are terminated by renal excretion?
Digoxin, Inotropes
Partially:
-Atropine
-Glycopyrrolate
-Milrinone
-Hydralazine
Which antimicrobials are terminated by renal excretion?
Aminoglycosides
Vancomycin
Cephalosporins
Penicillin
Partially:
-Sulfonamides
What is the effect of inhalation agents on the cardiac system?
Decrease contractility and SVR, causing hypotension.
-Dose-dependent cardiac depressants
-Dec intracellular Ca
-Do produce muscle relaxation, so can reduce dosage of NMB agents. However, worried about cardiac depression.
What is recommended for maintenance of anesthesia with Chronic renal insufficiency?
-N2O is safe to use
-TIVA is recommended (Short-acting)
-Cisatracurium (Hoffman Elimination)
-Regional is highly recommended
What is unique about Cis/Atracurium?
Eliminated via Hoffman elimination.
-Non-organ dependent
-Depends on pH and temperature
(Remember: Atracurium causes histamine release)
