Lab values beyond the numbers

Toni Petrillo, MD

Objectives

Ability to interpret a blood gasRecognition of abnormal Lab valuesTreatment of some of the more critical

values

Overview

Blood GasesChemistriesCBC’sCSF

Blood Gases

pHPCO2PO2Base ExcessO2 Sat

Blood Gases

pH Normal : 7.35 - 7.45 pH = acidosis; pH = alkalosis

Blood GasesPCO2

Normal 35-45mmHg• Increased PCO2

– Respiratory Acidosis– Compensated metabolic alkalosis

• Decreased PCO2– Respiratory Alkalosis– Compensated metabolic acidosis

PO2 80-100mmHg at sea level and RA

Blood Gases

Base Normal -3 to +3mMol/L Base excess indicates too much (metabolic

alkalosis) Base deficit indicates too little buffer

(metabolic acidosis)

Blood Gases: Metabolic Acidosis

Metabolic Acidosis• for every drop of meq/l in HCO3 pH

will decrease by 0.15• if respiratory compensation will have a in

PCO2

Blood Gases: Metabolic Acidosis

Causes– Renal losses of HCO3– GI Losses of HCO3– Uremia– DKA– Ingestion

» Aspirin» ETOH

Blood Gases: Respiratory Acidosis

PCO2 increased PCO2 by 10mmHg will PHbyunits– If metabolic compensation occurs will have

HCO3• Causes

– Brain Depression: sedative, CHI– Neuromuscular : Myasthenia, Gullian Barre– Lungs: Pulmonary Edema, FB, Pneumonia,

Pneumothorax, atelectasis– Other: Abdominal distention

Blood Gases: Metabolic Alkalosis

HCO3 increases• for every meq/L will pH by 0.15 units• If respiratory compensation PCO2• Related to conditions that have hypokalemia or loss

of hydrogen Ion• Causes

– Hypokalemia » GI: vomiting, Pyloric stenosis» Urine Loss: diuretics, antibiotics, Mg

Blood Gases: Metabolic Alkalosis

Causes cont– Loss Of H+

» vomiting» Hypercalcemia» chloride losing diarrhea

Blood Gases: Respiratory Alkalosis

PCO2 • For every PCO2 mmHg pH 0.08• If metabolic compensation HCO3• Caused by excessive removal of CO2

Blood Gases: Respiratory Alkalosis

• Causes– Respiratory Center Stimulation

» CNS (tumor, Infection)» Anxiety/Stress» Drugs

– Hypermetabolic States» Fever» Thyroid

– Mechanical Ventilation

Blood Gases: Examples

7.56 / 20/ 88/ -2

7.24/ 60/ 88/+2

7.55/ 40/88/ +15

7.12/ 40 /88 / -20

Blood Gases: Examples

7.30 / 60 / 88 / + 20

7.20/ 15 / 88/ -25

Chemistries (Basics)

Sodium (Na+)Potassium (K+)Chloride (Cl-)Bicarb (HCO3-)BUNCreatinine (Cr)GlucoseCalcium (Ca+)

Chemistries: Na+

Sodium Normal range 135-145mmol/L Life threatening

• < 120• >155

Can cause seizures, venous sinus thrombosis, CNS hemorrhage,

Chemistries : Na+Hyponatremia

Excessive H2O Cirrhosis, CHF Hypoalbuminemia

• Nephrotic• Malnutrition

Vomiting/ Diarrhea Diuretics SIADH Cerebral Salt Wasting

False• Hyperglycemia

– Na+ decrease 1.6 meq/l for each increase in glucose over 100

• hyperlipidemia– Na decrease

by .002 x lipid (mg/dl

Chemistries : Na+

Hypernatremia Diabetes Insipidus Diarrhea Dehydration Hypercalciuria Diabetes Hyperaldosteronism

Chemistries : Na+

Treatment is based partially on the causesif hypernatremic do not want to correct Na+

more than 10-15 meq per day will increase risk of cerebral edema 3-4 cc/kg of free water will decrease serum Na+

by 1 Meq/L for acute symptomatic hyponatremia may

use hypertonic saline 5-10 cc /kg

Chemistries: K+

Potassium Normal 3.4 - 4.7mmol/L Life threatening

• < 2.5• >6.5

Major complications Arrhythmia and EKG changes, weakness

Chemistries: K+

Hypokalemia Diuretics hypomagnesium Licorice RTA V/D Pyloric Stenosis DKA Antibiotics (ie: AmphoB)

Hyperkalemia Acidosis Renal Failure Muscle necrosis Blood Transfusions Hemolysis CAH

Chemistries: K+ and changes in EKGHyperkalemia

peaked T waves Widening of QRS loss of P wave ST segment

depression bradycardia ventricular

arrhythmias

Hypokalemia prominent u wave ST segment

depression ventricular

arrhythmias

Chemistries: K+Treatment of

Hypokalemia: KCL bolus

• 0.3 - 1 meq / kg• no more than 0.6

meq/kg/hour

Treatment of Hyperkalemia:

Insulin and Glucose NaHco3 Ca+ Kayexalate Lasix Albuterol

Chemistries: Cl -

Chloride Normal 95-105mEQ/L Hypochloremia

• Metabolic Alkalosis Respiratory Acidosis• CHF •Burns

Hyperchloremia• Metabolic Acidosis •Respiratory Alkalosis• Dehydration •RTA

Chemistries: HCO3-

Sodium Bicarbonate Normal: 20-26 mEQ / L Increased in Metabolic Alkalosis and

Compensated Respiratory Acidosis Decreased in Metabolic Acidosis and

Compensated Respiratory Alkalosis Causes previously discussed in blood gas

section

Chemistries: BUN

Blood Urea Nitrogen Normal: 5-20 mg/dl Elevated Tissue Necrosis

• Gi Bleed •High Protein Diet •Steroids• Shock •Dehydration •Diarrhea• Burns •Tissue Necrosis

Decreased• Anabolic Steroids •Malnutrition• Liver Dz •Pregnancy

Chemistries: Cr

Creatinine Normal: Child usually less than 1 Increased:

• Renal Dz• Muscle necrosis• hypovolemia

Chemistries: Glucose

Glucose Normal: 60-115mg/dl (infants >40) Hyperglycemia (AMS, Kusmal breathing)

• diabetes •Pancreatitis• Cushing's dz •Pheochromocytoma• drugs (ie: Steroids, Epi)

Hypoglycemia (jitters, Sz, Sweating)• Malaria •liver dz •Malignancy• enzyme deficiency •Malnutrition

Chemistries: Glucose

Treatment of Hypoglycemia Neonate or child: 0.5 to 1 gram / kg

• if using D25 would be 2-4 cc / kg– dilute D50 1:1 with sterile water

• if using D10 5-10 cc / kg– dilute D50 1:4

Adult: ampule of D50

Chemistries: Glucose

Treatment of Hyperglycemia Fluid bolus 10cc/kg NS insulin 0.05u - 1 unit/kg

If diabetic in DKA be very judicious of fluid administration and no NHCO3 unless cardiac instability

Chemistries: Ca+

Calcium Normal 8-11mg/dl Panic Value:<7 or > 12 (tetni, Sz, arrhythmia) Hypercalcemia (CHIMPS)

• C= Cancer• H= Hyperthyroid• I= Iatrogens• M= Multiple Myeloma• P= Primary Hyperparathyroid• S= Sarcoid

Chemistries: Ca+

Hypocalcemia• renal failure• hypoparathyroid• pseudohypoparathyroid• magnesium deficiency• anticonvulsants• Rickets• Pancreatitis• Blood transfusions

CBC’S

White Blood cell = WBC Differential

• Segs / polys •Lymphocytes• Eosinophils •Monocytes• Basophils •Bands

HemoglobinHematocritPlatelets

CBC: WBC

Birth 14d 1y 4y 8-21y adultWBC 9-30 5-20 6-18 5-15 4.5-

13.54.5-11

%poly 45 36 40 50 60 60lymh 30 53 53 40 30 32mono 12 8 5 8 8 4eos 2 2 1 1 1 3baso 1 1 1 1 1 1

CBC: WBC

Increased neutrophils physiologic

• newborn,pregnancy Pathologic

• acute infection• inflammatory dz• metabolic disorder• tissue necrosis• drugs• stress

Decreased neutrophils Infection

• bacterial– typhiod – septicemia

• Viral– Hepatitis –

mono– flu –

measles• myeloid hypoplasia• drugs

CBC: WBC

Increased Lymphocytes Infection

• Viral:– Hepatitis –mono– CMV –HSV

• Bacterial– Pertussis –

mumps Chronic Inflammation Metabolic Hematologic

• ALL

Decreased Lymphocytes

Increased Corticosteroids

immunodeficiency miliary Tb Lupus

CBC: WBC

Monocytes Elevated

• mumps• malaria• lymphomas

Eosinophils Elevated

• Parasitic dz •T-Cell leukemia• allergies •lupus

CBC: Hemoglobin / Hematocrit

Hemoglobin Normal

• 1 week: 13-20 •1 month: 11-17• 6months 10.5-14.5 •1 year: 11-15• 10years: 11-16•15years: 14-18M

12-16FHematocrit

Normal• 14-90d:35-49 •6m-1yr:30-40• 4-10yr: 31-43 •Adult:42-52M 37-47F

CBC: H/H

Increased Hct Polycythemia

• Heart Dz• Chronic Hypoxia

High Altitude Hemoconcentration

• Surgery• Burns• Dehydration

Decreased Hct Anemia

• Iron Deficiency• Malabsorbtion• HgSS• Toxin/drugs

– Lead• Infection

– Malaria– CMV

• Cancer

CBC: Platelets

Platelets Normal: 150-450 thousand Decreased platelets

• Decreased production– Marrow Depression: Aplastic Anemia, Radiation– Marrow infiltration: Leukemia– Congenital: Wiskott Aldrich, immune deficiencies

• Increased destruction– autoimmune: ITP, Mono, SLE– Coagulopathies: DIC, HUS, TTP– Drugs

CBC: Platelets

Increased Platelets• Reactive thrombocytosis

– infection– splenectomy– surgery/stress– Inflammatory dz.

• Thrombocythemia– myeloproliferative disorder– Chronic granulocytic leukemia

CSF

Condition Color Cells Protien Glucose

Normal clear 0-10 (20)lymphs

< 45 2/3 serum(55-80)

Bacterial Turbid 100-10,000segs

50-500 very low

TB Turbid 10-500lymphs

50-500 low

Viral Clear 10-500lymphs

45-200 Normal

CNSBleed

Bloody increasedRBC

45-100 Normal