Acid-Base Disturbances (48-50)

Homeostasis pH

7.35 - 7.45

What is the function of the lungs in regulating acid-base disturbances?

Control CO2

What is the function of the kidneys in regulating acid-base disturbances?

Control HCO3

What are the blood levels for acidemia?

<7.35

What are the blood acid levels for alkalemia?

>7.45

What is the condition where CO2 and acid are increased and pH is lowered?

respiratory acidosis

What is the condition where CO2 and acid are decreased but pH is raised?

respiratory alkalosis

What is the condition where HCO3- (Bicarb), acid, and pH are raised?

Metabolic alkalosis

What is the condition where HCO3- (bicarb), base, and pH are lowered?

Metabolic acidosis

What levels indicate hyperventilation?

Decrease in CO2, decrease in acid, and an increase in pH

What is Hyperventilation also known as?

Respiratory alkalosis

When you are breathing quicker, what are you doing and what are you inducing?

blowing off more CO2

Respiratory alkalosis

When you are breathing slower, what are you doing and what are you inducing?

retaining CO2

respiratory acidosis

What do the kidneys regulate?

Regulate Bicarb and hydrogen excretion

What are the common causes of Respiratory Acidosis?

Anything that makes you unable to breath effectively

There are 4 major groups of causes for Respiratory Acidosis, what are they?

CNS Disorders

Neuromuscular Disorders

Airway Obstruction

Impaired gas exchange

What is respiratory alkalosis?

Occurs because of conditions that increase rate or depth of breathing

How do you treat respiratory alkalosis?

Fix underlying cause

What is Metabolic Acidosis?

Body compensates by using lungs

• Breathe faster

What is Metabolic alkalosis?

CO2 => acid

Body compensates by hypoventilating and retaining CO2

How do you read ABG

Look at pH (detremine acidemia/alkalemia)

Look at CO2 & Bicarb (which explains the pH?)

What is the formula for determining Anion Gap?

AG = Na+ - (Cl- + HCO3-)

What is a normal anion gap levels?

3-11 mEq/L

What is an increased anion gap?

>12 mEq/L

What happens when a high anion gap metabolic acidosis?

Extra acid uses up bicarb

What happens when high anion gap metabolic acidosis occurs?

acids negatively charged part becomes an unmeasured anion = anion gap goes up

What is the most common cause of high AG metabolic acidosis?

lactic acidosis

What are other causes of High AG metabolic acidosis?

Ketoacidosis = DKA, Alcoholic ketoacidosis

Kidney Failure = Kidneys can’t excrete acids

Toxic Ingestions

• MUDPILES

High AG = extra acid was added/accumulated

What are MUDPILES stand for?

Methanol Poisoning

Uremia

Diabetic Ketoacidosis

Propylene Glycol

Isoniazid

Lactic Acidosis

Ethylene Glycol

Salicylic Acid

What is normal anion gap metabolic acidosis?

Hyperchloremic metabolic acidosis = loss bicarbonate replaced by chloride

What occurs in Type 1 Renal Tubular Acidosis?

inability to excrete hydrogen properly; occurs in distal tubule

What are the drugs associated with Type 1 Renal Tubular Acidosis?

Lithium

Amphotericin B

Ifosfamide

What occurs in type 2 Renal Tubular Acidosis?

cant reabsorb bicarbonate properly; occurs in proximal tubule

What are the drugs associated with Type 2 Renal Tubular Acidosis?

Carbonic Anhydrase Inhibitors

What occurs in Type IV Renal Tubular Acidosis?

low aldosterone activity which results in less hydrogen excretion, hyperkalemia

How do you treat Type IV Renal Tubular Acidosis?

correct hyperkalemia

consider fludrocortisone

What is the idea of compensation?

The body sees a problem and tries to use the other system to fix it

If problem is metabolic, the lungs compensate

If problem is respiratory, the kidneys compensate

What is Mixed Acid-Base Disorders?

2 main problems at the same time

What occurs in metabolic acidosis + respiratory acidosis?

both cause acidosis

Increase of CO2, Decrease in Bicarb

What happens when there is a mix of pH disturbances?

conditions can become very severe

What are examples of severe conditions that come from a mix of pH disturbances?

Cardio/Respiratory arrest

Chronic lung disease

Shock

How do you treat a mix acid-base disorder?

Treat both

What occures in Metabolic acidosis + respiratory alkalosis?

pH looks normal or close to normal, but it doesn’t mean it is

What occurs in Metabolic alkalosis + Respiratory Acidosis?

pH is close to normal

What is an example of a metabolic alkalosis + respiratory acidosis?

COPD

What is chloride responsiveness?

Urine cl- <10mEq/L

What is chloride responsiveness associated with?

N/V

Chloride loss

Diuretics

How do you treat chloride responsiveness?

Give NaCl

What is Chloride-Resistant?

Urine Cl- >20mEq/L

What is chloride resistant also known as?

Mineralcorticoid problem/excess aldosterone effect

How do you treat chloride resistance?

Potassium Sparing Diuretics

When do we use Hydrochloric Acid?

Severe metabolic alkalosis taht does not respond to standard treatment

What is the initial pH of Hydrochloric acid?

>7.55

What is the treatment use of Hydrochloric acid?

Blood is too basic and normal treatment aren’t working, so give acids

What does HCl do to the body?

gives body H+, helping bring pH down

What is the treatment for Metabolic Acidosis?

Don’t automatically give Bicarb to every patient with metabolic acidosis

Treat underlying cause (disease, loss, etc)

When do we use bicarbonate?

IV alkalizing therapy beneficial for

1) Type 1 RTA

2) Severe metabolic acidosis from diarrhea

3) Poisoning/intoxication (Salicylate overdose)

What is the pH level for acute severe metabolic acidosis?

<7.2

How do you treat acute severe metabolic acidosis?

depends on underlying cause, CV status which are indication for hemodialysis

When is bicarbonate harmful?

Hyponatremia

DKA

HF

AKI

What is the formula that helps determine bicarb deficit?

0.5 x BW x [desired bicarb - current bicarb]