moonlight medicine

60

Click here to load reader

Upload: ham

Post on 10-Jan-2016

95 views

Category:

Documents


0 download

DESCRIPTION

Moonlight Medicine. Laboratory Interpretation. Adrian Paul J Rabe, MD, DPCP. Laboratory Interpretation. Supplements the history and physical examination Objective evidence of disease/health. Laboratory Interpretation. Complete blood count Bleeding tests PT/PTT, Bleeding time - PowerPoint PPT Presentation

TRANSCRIPT

Page 1: Moonlight Medicine

Moonlight Medicine

Adrian Paul J Rabe, MD, DPCP

Laboratory Interpretation

Page 2: Moonlight Medicine

Laboratory Interpretation

• Supplements the history and physical examination

• Objective evidence of disease/health

Page 3: Moonlight Medicine

Laboratory Interpretation

• Complete blood count• Bleeding tests– PT/PTT, Bleeding time

• Blood chemistry– Electrolytes (Na, K, Ca, Mg)– BUN and Creatinine– Liver enzymes (AST, ALT) and bilirubins

• Urinalysis• Arterial Blood Gas

Page 4: Moonlight Medicine

CBC

Page 5: Moonlight Medicine

Complete Blood count

• Hemoglobin and Hematocrit– High hemoglobin: Erythrocytosis– High hematocrit: Dehydration

(hemoconcentration) or erythrocytosis– Low hemoglobin/hematocrit: anemia

Page 6: Moonlight Medicine

Complete Blood count

• Hemoglobin and Hematocrit–MCV – size of the RBC (“-cytic”)–MCH – amount of hemoglobin in the RBC

(“-chromic”)–MCHC – concentration of hemoglobin the

RBC– RDW – distribution of cell sizes

Page 7: Moonlight Medicine

Complete Blood count

• Hemoglobin and Hematocrit– Microcytic Hypochromic (ITIM)

• Iron deficiency anemia or chronic blood loss• Anemia of chronic inflammation• Thalassemia• Myelodysplasia

– Normocytic Normochromic• Early stages of microcytic, hypochromic disease• Acute blood loss• Hemolytic Anemia

– Megaloblastic• Folate or Vitamin B12 deficiency

Page 8: Moonlight Medicine

Complete Blood count

• Hemoglobin and Hematocrit– Transfusion changes• For every unit of packed RBC, increase in 10

g/L• Start of equilibration: 6 hours post transfusion• Full equilibration: 72 hours post transfusion

Page 9: Moonlight Medicine

Complete Blood count

• WBC– Neutrophils and stabs• Elevated: Bacterial or early viral Infection,

Stress, Inflammation• Low: Neutropenia• Absolute neutrophil count (ANC) = WBC x

(Neutrophils in %) x 1000

– Lymphocytes • Elevated: viral/fungal/mycobacterial infection• Low: Lymphopenia• Absolute lymphocyte count (ALC) = same as

ANC

Page 10: Moonlight Medicine

Complete Blood count

• Platelets– Very evanescent– Low platelets: Consumption, Viral

infection– Hard to predict platelet count after

transfusion– Adults: never transfuse less than 4 units• Coats the tubing• A Repeat platelet count should be taken

immediately up to 2 hours post transfusion

Page 11: Moonlight Medicine

Bleeding Tests

Page 12: Moonlight Medicine

Laboratory Interpretation

• PT/PTT– Prothrombin time: Measures the extrinsic pathway

(1572 = Factors 1, 10, 5, 7 and 2)• Liver disease: poor production of factor VII• Warfarin

– Partial thromboplastin time: Measures the intrinsic pathway• Heparin• APAS• Coagulation factor deficiency (hemophilia)

– Both prolonged• DIC• End-stage liver disease• Warfarin

Page 13: Moonlight Medicine

Laboratory Interpretation

• Bleeding Time– Does not predict bleeding risk even in

surgery– No longer recommended

Page 14: Moonlight Medicine

Blood Chemistry

Page 15: Moonlight Medicine

BUN and Creatinine

• BUN – produced by the body and converted through the urea cycle– Increased BUN: Increased production– GI bleed

• Creatinine – produced by the muscles, excreted by the kidney with little tubular reabsorption– Increased Creatinine: Increased

production or decreased clearance

Page 16: Moonlight Medicine

BUN and Creatinine

• BCR = BUN:Creatinine ratio– BUN/Creatinine in mmol x 247– If > 20 = pre-renal– If 10-15 = intrinsic renal

• Replaced by the Fractional excretion of sodium (FENa)– (UNaPCr)/(PNaUCr)

– If < 1% = pre-renal– If > 2% = intrinsic renal failure

Page 17: Moonlight Medicine

BUN and Creatinine

• Creatinine Clearance = GFR– (140-age) x weight x 88.4 (x 0.85 if

female)72 x Plasma creatinine

– Estimates amount of creatinine filtered

Page 18: Moonlight Medicine

Sodium (Na)

• Correlated with body water• Sodium is normally present in

equimolar amounts• Water diffuses through

semipermeable compartments to equilibrate

Page 19: Moonlight Medicine

Sodium (Na)

• Total body water–% body water x kg body weight–Males: 60%– Females and Elderly (Age > 60): 50%

• Plasma osmolality– 2(Na+K) + BUN + RBS in mmol/L– BUN/2.8 if in mg/dL– RBS/18 if in mg/dL– Normal: 275-290 mmol/L

Page 20: Moonlight Medicine

Sodium (Na)

• Total body water– 50 kg male?– 70 kg female?

• Plasma osmolality– Na 135, K 3.5, BUN 8, RBS 5– Na 125, K 4.0, BUN 10, RBS 8

Page 21: Moonlight Medicine

Sodium (Na)

• Hyponatremia– Check Plasma osmolality– High osmolality• Hyperglycemia• Mannitol

– Normal osmolality• Hyperlipidemia/proteinemia• Bladder irrigation

– Low osmolality• Check Urine output

Page 22: Moonlight Medicine

Sodium (Na)

• Hyponatremia (Low osmolality)–Maximal urine output• Primary polydipsia (patient drinks a lot,

diluting Na)• Pituitary problem/fever

– Poor urine output• Check ECF volume

Page 23: Moonlight Medicine

Sodium (Na)

• Hyponatremia (Low osmolality, Poor UO)– Increased ECF volume (dilutional)

• Heart failure• Liver failure• Kidney failure/nephrotic syndrome

– Normal ECF volume• SIADH• Hypothyroidism• Adrenal insufficiency

– Decreased ECF volume• Loss of Na (renal, sweat, diuretics)

Page 24: Moonlight Medicine

Sodium (Na)

• Hypernatremia– Check ECF volume– High ECF volume• Use of hypertonic solutions

– Low ECF volume• Check Urine output

Page 25: Moonlight Medicine

Sodium (Na)

• Hypernatremia (Low ECF volume)–Minimal urine output• Free water losses/Dehydration

– Good urine output• Check urine osmolality• 24 hour urine TV, Na, K, Crea

Page 26: Moonlight Medicine

Sodium (Na)

• Hypernatremia (Low ECF volume, Good UO)– Urine osmolality > 750• Diuresis

– Urine osmolality < 750• Diabetes insipidus• Central vs Nephrogenic (through response to

DDAVP)

Page 27: Moonlight Medicine

Sodium (Na): Correction

• Hyponatremia– Increased ECF, no HypoNa symptoms• Used isotonic solutions• Restrict fluid to less than urine output• Loop diuretics

– Normal ECF, no HypoNa symptoms• Restrict fluid

– Low ECF or with HypoNa symptoms• Correct!

Page 28: Moonlight Medicine

Sodium (Na): Correction

• Hyponatremia Correction– No more than 10-12 mmol/day (0.5

mEqs/hour)–Na deficit = TBW x (Desired-Actual Na)– Calculate sodium deficit of 10-12 mmol/day

• E.g. Na 100 in a 50 kg female• Desired sodium should be 110-112• TBW = 50 x 50%= 25 L• Na def = 25 x 12 = 300 mmol in 24h• 0.9% pNSS 1L x 12h

5% NaCl 855

3% NaCl 513

0.9% NaCl 154

0.45% NaCl 77

0.2% NaCl 34

Plain LR 130

D5W 0

Page 29: Moonlight Medicine

Sodium (Na): Correction

• Hypernatremia– Stop ongoing water losses– Should correct dehydration– Oral correction is the safest– No more than 10-12 mmol per day

(0.5mmol/hr)

Page 30: Moonlight Medicine

Sodium (Na): Correction• Hypernatremia Correction– Water deficit = TBW x [(Actual-140)/140]– Change in serum Na = (infusate Na – serum

Na)(TBW+1)

– Amount of infusate = 10 or 12/Change in serum Na• E.g. Na 160 in a 50 kg female• TBW = 50 x 50%= 25 L• Water deficit = 25L x [(160-140)/140]

= 3.57 L• Change in serum Na = (77-160)/(25+1)

= -3.19 mmol for every liter of 0.45% NaCl

• Amount of 0.45% NaCl = 12/3.19 = 3-4 L per day• 0.45 NaCl 1L x 6-8h

0.9% NaCl 154

0.45% NaCl 77

0.2% NaCl 34

Plain LR 130

D5W 0

Page 31: Moonlight Medicine

Sodium (Na): Correction• 60 kg 23 year-old female with

diarrhea and vomiting presents with new-onset seizure– BP 90/60, HR 110, RR 24, Febrile to

touch– BUN 12, Crea 127, Na 150, K 3.5• Creatinine Clearance• Plasma Osmolality• Total Body Water• H20/Na Deficit• Plain LR is available

– Change in Na per liter– Order

0.9% NaCl 154

0.45% NaCl 77

0.2% NaCl 34

Plain LR 130

D5W 0

• 57• 311• 30 L• 2 L

• -0.65mmol/L• 15 L of plain LR • 1L per hour for 4

hours

Page 32: Moonlight Medicine

Sodium (Na): Correction• 50 kg 40 year-old male diabetic

with decreased sensorium– BP 140/80, HR 90, RR 28, afebrile– BUN 8, Crea 150, Na 115, K 3.5, Cl 90• Creatinine Clearance• Plasma Osmolality• Total Body Water• H20/Na Deficit• Daily Na correction• Plain LR is available

0.9% NaCl 154

0.45% NaCl 77

0.2% NaCl 34

Plain LR 130

D5W 0

• 40• 239• 30 L• 750 mEqs• 360 mEqs• Plain LR 1L x 115

cc/hr

Page 33: Moonlight Medicine

Potassium (K)

• Hypokalemia (<3.5 mmol/L)– 24h urine K and ABG– Urine K > 15 mmol/d• Acidotic = lower GI losses• Alkalotic = vomiting, sweat/renal losses,

diuresis

– Urine K < 15 mmol/d• Acidotic = DKA, RTA• Alkalotic = vomiting, Bartter’s/Liddle’s,

HypoMg

Page 34: Moonlight Medicine

Potassium (K): Correction

• Hypokalemia Correction– Concentration• 60 mEqs via central line• 40 mEqs via peripheral line

– Rate• ≤ 20 mmol/h unless with paralysis, malignant

ventricular arrhythmias

– Amount• Every 1mmol/L decrease = 200-400 mmol

deficit• pNSS is the ideal medium

Page 35: Moonlight Medicine

Potassium (K): Correction

• Hypokalemia Correction– 19 year-old male comes in for progressive

lower extremity weakness– K 2.7– Deficit?– Correction via peripheral line?

• 160 to 320 mEqs• pNSS 1L + 40

mEqs KCl x 6 hours, both arms

Page 36: Moonlight Medicine

Potassium (K)

• Hyperkalemia (>5.0 mmol/L)– Failure of excretion• Intrinsic Renal problem• Drug-induced (spironolactone, K-sparing

diuretics)• Iatrogenic (overcorrection)

– Intake of massive amounts

Page 37: Moonlight Medicine

Potassium (K): Correction

• Hyperkalemia Correction– Calcium gluconate (10% solution) over 2-3

minutes– NaHCO3 push– Glucose (G-I) solution = 10 u regular

insulin + 1 vial D50-50– Beta-agonists (salbutamol)– Diuretics (Furosemide)– Dialysis

Page 38: Moonlight Medicine

Calcium (Ca) and Albumin

• Corrected Calcium– (40-actual albumin) x 0.02 + Actual

calcium– Do for both increased and decreased

calcium

Page 39: Moonlight Medicine

Calcium (Ca) and Albumin

• Hypocalcemia Correction– Chronic

• Calcium Carbonate best taken with food (acid soluble)

• Calcium citrate can be taken anytime• <600 mg of calcium per dose• Age 19-50: 1000 mg/day• Age 51 and older: 1200 mg/day

– Acute, symptomatic• Calcium gluconate 10 mL of a 10% solution diluted

in D50-50 or 0.9% saline over 5 minutes• Calcium gluconate drip 10 ampules or 900 mg in 1L

of D5 or 0.9% saline over 24 hours

Page 40: Moonlight Medicine

Calcium (Ca) and Albumin

• Hypercalcemia Correction– Volume expansion (4-6 L of 0.9% saline in

first 24 hours) until normal volume status is restored

– Loop diuretics (Furosemide)– Bisphosphonates• Zoledronic Acid 4 mg IV over 30 minutes• Pamidronate 60-90 mg IV over 2-4 hours• Onset of action is 1-3 days

– Dialysis

Page 41: Moonlight Medicine

Magnesium (Mg)

• Part of the inseparable trio (K, Ca, Mg)

• Hypomagnesemia needs to be corrected to facilitate correction of other electrolytes

• 1g Mg = increase in 0.1 mmol/L– Target 1.0 mmol/L in Cardiac patients– Target 0.8 mmol/L in Renal patients– E.g. post-MI patient with Mg 0.6 mmol/L• MgSO4 4g in D5W 250 cc x 24h

Page 42: Moonlight Medicine

Liver enzymes and bilirubins

• Prothrombin time• Albumin• TB, DB, IB– Elevated DB = Cholestatic– Elevated IB = Hemolytic– Both could be elevated in liver failure

• AST and ALT– NOT liver function test– Help estimate amount of liver parenchymal

damage– Hundreds to Thousands: Toxic, Viral, Ischemic– AST: ALT ratio > 2:1, likely alcoholic

Page 43: Moonlight Medicine

Lipid profile

• Total Cholesterol (>200 mg/dL)– Statin

• HDL (<40 mg/dL in males, < 50 mg/dL in females)– Nicotinic Acid– Statin

• LDL (> 150 mg/dL)– Statin

• Triglycerides (> 150 mg/dL)– Fibrate (fenofibrate)– Statin

Page 44: Moonlight Medicine

Urinalysis

Page 45: Moonlight Medicine

Urinalysis

• pH• Specific gravity• Albumin• Glucose• WBC• RBC• Casts• Crystals• Epithelials

Page 46: Moonlight Medicine

Urinalysis

• pH– Important in drug excretion– E.g. Methamphetamines eliminated with

acidic pH

• Specific gravity– If ≤1.010: hydrated vs inability to

concentrate– If ≥ 1.020: dehydrated vs compensation by

concentration

• Albumin• Glucose

Page 47: Moonlight Medicine

Urinalysis

• Albumin– Related to the integrity of the basement

membrane– Albuminuria: infection, nephrotic

syndrome/kidney disease

• Glucose– Non-specific–May be elevated in diabetes

Page 48: Moonlight Medicine

Urinalysis

• Epithelials– Used to gauge urine catch– If < 5: “clean catch”

• WBC– If > 5: infection in the presence of a clean

catch

• RBC– If > 5: suspect kidney injury (hematuria?

Nephritis? Infection?)

Page 49: Moonlight Medicine

Urinalysis

• Casts–WBC casts: pyelonephritis or allergic

interstitial nephritis– RBC casts: hematuria– Broad casts: chronic kidney disease

• Crystals– Very non-specific– Even “uric acid crystals” are seen in

normal patients

Page 50: Moonlight Medicine

Arterial Blood Gas

Page 51: Moonlight Medicine

Arterial Blood Gas

• pH – reflects primary defect

• pCO2– Elevated: decreased ventilation of CO2– Decreased: increased ventilation of CO2

• pO2– Elevated: too high FiO2, hemoglobin

abnormality– Decreased: Poor oxygenation, or oxygen

binding

Page 52: Moonlight Medicine

Arterial Blood Gas

• HCO3– Elevated: Alkaline– Decreased: Acidic

• O2 saturation– If >90%: regular pulse oximeter cannot

reliable distinguish frequencies

Page 53: Moonlight Medicine

ABG Interpretation

• Identify adequate oxygenation and saturation– Oxygenation: enough oxygen in the blood

(pO2)– Saturation: enough oxygen bound to RBCs

(O2 Sat)

Page 54: Moonlight Medicine

ABG Interpretation

• Identify Acid-Base problem:– Acidosis or Alkalosis?– Choose between pCO2 and HCO3• Acidosis: increased pCO2 OR decreased HCO3• Alkalosis: decreased pCO2 OR increased HCO3

– Establish predominant pathology• (pCO2 – 40)/40• (HCO3-24)/24• Biggest absolute value is the predominant

pathology

Page 55: Moonlight Medicine

ABG Interpretation

• Identify Acid-Base problem:– Determine if primary problem is

compensated• (pCO2 – 40)/40• (HCO3-24)/24• Biggest absolute value is the predominant

pathology

Page 56: Moonlight Medicine

ABG Interpretation• Identify Acid-Base problem:

Predominant pathology CompensationMetabolic Acidosis

(Low HCO3)For every mmol decrease in

HCO3, pCO2 decreases by 1.25Metabolic Alkalosis

(High HCO3)For every mmol increase in

HCO3, pCO2 increases by 0.75

Respiratory Acidosis(High pCO2)

AcuteFor every mmol increase in

pCO2, HCO3 increases by 0.1Chronic

For every mmol increase in pCO2, HCO3 increases by 0.4

Respiratory Alkalosis(Low pCO2)

AcuteFor every mmol decrease in

pCO2, HCO3 decreases by 0.2Chronic

For every mmol decrease in pCO2, HCO3 decreases by 0.4

Page 57: Moonlight Medicine

ABG Interpretation

• If there is metabolic acidosis– Take anion gap• (Na + K) – (Cl + HCO3)• Normal is 10 to 12

– HAGMA: MUDPILES• Methanol, uremia, DKA, Propylene

glycol/Paraldehyde, Isoniazid/Iron, Lactic Acid, Ethanol/Ethylene glycol, Sulfates/Salicylates

– NAGMA: STRaND• Spironolactone, TPN, RTA, Na-containing

solutions, Diarrhea

Page 58: Moonlight Medicine

ABG Interpretation

• If there is HAGMA– Take changes in anion gap and HCO3– Δ AG > Δ HCO3 = HAGMA with Metabolic

alkalosis– E.g. Uremia with vomiting

• If there is NAGMA– Take changes in HCO3 and Cl– Δ AG > Δ Cl= NAGMA with HAGMA– E.g. Diarrhea and lactic acidosis,

treatment of DKA

Page 59: Moonlight Medicine

ABG Interpretation

• 40• 239• 30 L• 750 mEqs• 360 mEqs• Plain LR 1L x 115

cc/hr

• 50 kg 40 year-old male diabetic with decreased sensorium– BP 140/80, HR 90, RR 28, afebrile– BUN 8, Crea 150, Na 115, K 3.5, Cl 90• Creatinine Clearance• Plasma Osmolality• Total Body Water• H20/Na Deficit• Daily Na correction• Plain LR is available

Page 60: Moonlight Medicine

ABG Interpretation

– pH 7.1, pCO2 28, pO2 78, HCO3 10, O2 Sat 88%• Oxygenation /Saturation?• Acidosis or Alkalosis?• Respiratory or Metabolic?• Compensated?• Anion Gap?• Secondary problems?

• Poor; Poor• Acidosis• Metabolic• Expected pCO2 27.5;

compensated • 15 (High Anion Gap)• 3 < 14; None

• 50 kg 40 year-old male diabetic with decreased sensorium– BP 140/80, HR 90, RR 28, afebrile– BUN 8, Crea 150, Na 115, K 3.5, Cl 90