Acid Base Balances and Imbalances

cells are sluggish

​​Acidic

cells are jumpy

​​Alkalosis

Multiple Choice

Which of the following statements about pH and hydrogen ion concentration is correct?

• An increase in H+ concentration causes pH to fall, leading to increased acidity.

• A decrease in H+ concentration causes pH to fall, leading to increased acidity.

• An increase in H+ concentration causes pH to rise, leading to decreased acidity.

• A decrease in H+ concentration causes pH to rise, leading to increased acidity.

Multiple Choice

Which of the following systems does NOT play a direct role in maintaining normal acid-base balance in the body?

• Digestive system

• Buffer systems

• Respiratory system

• Renal system

• Too much acid (H+) → Buffers grab it (like a sponge soaking up a spill).

• Too much base → Buffers let go of H+ (like wringing the sponge back out).

Buffer Systems

Multiple Select

Which of the following are major buffer systems in the body?

• Bicarbonate–carbonic acid buffer system

• Phosphate buffer system

• Protein buffers

• Chloride buffer system

Multiple Choice

What is the main function of the respiratory system?

• to provide oxygen and remove carbon dioxide from the body
• to bring oxygen to the body
• to break down food and absorb nutrients
• to remove oxygen from the body and deliver carbon dioxide

Multiple Choice

What are the tiny air sacs at the end of the Bronchioles, that transfer oxygen into the blood stream?

• Trachea
• Bronchi
• Alveoli
• Larynx

Multiple Choice

When you breathe in air, you inhale oxygen into your lungs and exhale ____.

• carbon dioxide
• oxygen
• nitrogen
• carbon monoxide

Too much in blood causes toxicity
Acidity

​​Too much CO2

Too little in blood
Alkaline

​​Too little CO2

Multiple Choice

The normal range for CO2 is

• 35-45 mmHg

• 37-47 mmHg

• 30-40 mmHg

• 32-42 mmHg

Multiple Choice

Which one of the following is an ABG's normal range for the partial pressure of oxygen (PaO2) in the blood?

• PaO2: 80-100 mmHg

• PaO2: 80-90 mmHg

• PaO2: 75–95 mmHg

• PaO2: 85–95 mmHg

Multiple Choice

Is CO2 an acid or a base?

• Acid

• Base

Multiple Choice

A patient who was helping getting people out of a burning building comes to the ER with cough and shortness of breath. The SaO2 is 100%. If any, what acid / base imbalance do you suspect?

• No imbalance

• Respiratory Alkalosis

• Respiratory Acidosis

• Metabolic Acidosis

Excrete more H+ in urine
Excrete toxins

Filters

Reuse bicarbonate from the urine to neutralize the blood

​​Reabsorbs

Multiple Choice

What is the primary function of the kidneys in acid-base balance?

• Eliminate nonvolatile acids

• Increase CO2 retention

• Stimulate respiratory center

• Release protein buffers

Compensation

Backup Plan!

When one system slacks the other covers or helps
Both fail = crash

Fully vs Partially
Fully = pH is NORMAL!

Open Ended

What are the main compensatory mechanisms the body uses to restore normal pH and homeostasis?

Multiple Choice

Decompensation occurs when:

• Causative problem becomes more severe

• Additional problems occur

• Compensation mechanisms are exceeded or fail

• All of the above

Renal Failure
Diabetes*
Lactic Acidosis*
Ingestion of Toxins*
Diarrhea
Too much NS IV

​​Acidosis

Upper GI loss (NGT, Vomiting)
Medications (Diuretics)

​​Alkalosis

​Metabolic

​A normal average anion gap value is 12 mEq/L (typical range = 8 – 16 mEq/L). *>12

Multiple Choice

Which of the following clients is most at risk for developing metabolic acidosis?

• A client with insulin-dependent diabetes mellitus

• A client with acute vomiting

• A client with anxiety-induced hyperventilation

• A client taking excessive antacids

Multiple Select

Which of the following are laboratory findings associated with respiratory acidosis?

• Elevated PCO2

• Low serum bicarbonate

• Elevated serum bicarbonate

• Low PCO2

Multiple Choice

Which of the following is a common cause of chronic respiratory acidosis?

• Chronic obstructive pulmonary disease

• Acute diarrhea

• Excessive antacid intake

• Early stage vomiting

Multiple Choice

A patient with heart failure comes to the ER with complaints nausea and vomiting over the last 3-4 days. What acid / base imbalance do you suspect?

• respiratory alkalosis

• respiratory acidosis

• metabolic acidosis

• metabolic alkalosis

Multiple Choice

When determining how to interpret acid base disorders, what is the FIRST lab value to look at?

• pH

• Bicarbonate

• Sodium

• Calcium

Multiple Choice

When determining to interpret acid base disorders, a pH >7.45 is classified as which of the following?

• alkalosis

• ketogenesis

• ketolysis

• Gluconeogenesis

Multiple Choice

When determining how to interpret acid base disorders, which three lab values are crucial?

• pH, Na, HC03

• pCO2, HCO3, p02

• pH, pC02, HC03

• abcdefg

Multiple Choice

The nurse is assigned a client admitted with renal failure and an arterial blood pH level of 7.29. Which lab result would the nurse expect?

• Serum sodium 138 mEq/L

• Serum glucose 145 mg/dL

• Serum creatinine 0.4 mg/dL

• Serum potassium 5.9 mEq/L

Multiple Choice

A client is brought to the ED after passing out in a local department store. The client has been fasting and has ketones in the urine. Which acid-base imbalance would the nurse expect to assess in this client?

• Metabolic acidosis

• Respiratory alkalosis

• Metabolic alkalosis

• Respiratory acidosis

Multiple Choice

pH: 7.30

PaCO₂: 48 mmHg
HCO₃⁻: 25 mEq/L

• Respiratory Acidosis

• Respiratory Alkalosis

• Metabolic Acidosis

• Metabolic Alkalosis

Multiple Choice

pH: 7.50
PaCO₂: 39 mmHg
HCO₃⁻: 30 mEq/L

• Respiratory Acidosis

• Respiratory Alkalosis

• Metabolic Acidosis

• Metabolic Alkalosis

Multiple Choice

pH: 7.32
PaCO₂: 36 mmHg
HCO₃⁻: 18 mEq/L

• Respiratory Acidosis

• Respiratory Alkalosis

• Metabolic Acidosis

• Metabolic Alkalosis

Multiple Choice

pH: 7.46
PaCO₂: 32 mmHg
HCO₃⁻: 23 mEq/L

• Respiratory Acidosis

• Respiratory Alkalosis

• Metabolic Acidosis

• Metabolic Alkalosis

Multiple Choice

pH: 7.27
PaCO₂: 42 mmHg
HCO₃⁻: 17 mEq/L

• Respiratory Acidosis

• Respiratory Alkalosis

• Metabolic Acidosis

• Metabolic Alkalosis

Multiple Choice

pH: 7.53
PaCO₂: 28 mmHg
HCO₃⁻: 24 mEq/L

• Respiratory Acidosis

• Respiratory Alkalosis

• Metabolic Acidosis

• Metabolic Alkalosis

Multiple Choice

pH: 7.49
PaCO₂: 40 mmHg
HCO₃⁻: 28 mEq/L

• Respiratory Acidosis

• Respiratory Alkalosis

• Metabolic Acidosis

• Metabolic Alkalosis

Multiple Choice

pH: 7.31
PaCO₂: 52 mmHg
HCO₃⁻: 28 mEq/L

• Partially Respiratory Acidosis

• Partially

  Respiratory Alkalosis

• Partially

  Metabolic Acidosis

• Partially

  Metabolic Alkalosis

Multiple Choice

pH: 7.49
PaCO₂: 48 mmHg
HCO₃⁻: 30 mEq/L

• Partially Respiratory Acidosis

• Partially

  Respiratory Alkalosis

• Partially

  Metabolic Acidosis

• Partially

  Metabolic Alkalosis

Multiple Choice

pH: 7.28
PaCO₂: 30 mmHg
HCO₃⁻: 18 mEq/L

• Partially Respiratory Acidosis

• Partially

  Respiratory Alkalosis

• Partially

  Metabolic Acidosis

• Partially

  Metabolic Alkalosis

Multiple Choice

pH: 7.50
PaCO₂: 28 mmHg
HCO₃⁻: 20 mEq/L

• Partially Respiratory Acidosis

• Partially

  Respiratory Alkalosis

• Partially

  Metabolic Acidosis

• Partially

  Metabolic Alkalosis

Multiple Choice

A 17-year-old patient presents to the ED complaining of a tight feeling in their chest, shortness of breath as well as some tingling in their fingers and around their mouth. They have no significant past medical history and are not on any regular medication. An ABG is performed on the patient while they’re breathing room air and the results are shown below:

PaO2: 105 mmHg

pH: 7.49

PaCO2: 24 mmHg

HCO3–: 22 mEq/L

• Respiratory Alkalosis

• Respiratory Acidosis

• Metabolic Acidosis

• Metabolic Alkalosis

Multiple Choice

A 48-year-old male has been admitted with a 24 hour history of abdominal distention and profuse vomiting. A CT scan reveals a large mass causing bowel obstruction. As part of the patient’s assessment, the surgical resident requests that you check his blood gas (on air), with the results shown below:

PaO2: 95.2 mmHg

pH: 7.50

PaCO2: 41 mmHg

HCO3-: 29 mEq/L

• Respiratory Acidosis

• Respiratory Alkalosis

• Metabolic Acidosis

• Metabolic Alkalosis

Multiple Choice

You’re asked to review a 59-year-old female who has been admitted the acute medical ward of your hospital. The nurse tells you that she appears short of breath despite currently receiving 3 liters of oxygen via nasal cannula.

You take an arterial blood gas which reveals the following results:

PaO2: 68.2 mmHg

pH: 7.30

PaCO2: 63 mmHg

HCO3-: 29 mEq/L

• Respiratory Acidosis with Metabolic Compensation

• Respiratory Acidosis

• Metabolic Acidosis with Respiratory Compensation

• Metabolic Alkalosis

Multiple Choice

An 89-year-old patient presents with fever, rigors, hypotension and reduced urine output. They appear confused and are unable to provide any meaningful history. The care home that the patient came from has provided some basic documentation. You look through the information available and note that the nurse changed this patient’s catheter 24 hours ago. The medical doctor initiates antibiotics, aggressive fluid resuscitation and asks you to perform an arterial blood gas, with the results shown below. The patient was not on oxygen at the time of the ABG.

PaO2: 93 mmHg

pH: 7.29

PaCO2: 41.2 mmHg

HCO3-: 15 mEq/L

• Metabolic Acidosis with Respiratory Compensation

• Metabolic Acidosis

• Metabolic Alkalosis

• Respiratory Acidosis

Multiple Choice

A 56-year-old man was found unconscious at home with a respiratory rate of 6 breaths per minute and pinpoint pupils. An ambulance was called and the paramedics administered some naloxone. On arrival to ED his ABG showed the following (not on oxygen at the time of the ABG):

PaO2: 59 mmHg

pH: 7.31

PaCO2: 53 mmHg

HCO3-: 22 mEq/L

• Respiratory Acidosis with Metabolic Compensation

• Metabolic Acidosis

• Respiratory Acidosis

• Respiratory Alkalosis

Multiple Choice

A 77-year-old lady was admitted to hospital 10 days ago with a fractured neck of femur. The orthopedic team repaired the fracture and she has been an inpatient on the orthopedic ward recovering ever since. The patient’s nurse is becoming increasingly concerned as the patient’s oxygen requirements are increasing (she is now on 3L) and the patient is now tachypneic (respiratory rate 35). In addition, the patient has recently started complaining of calf pain.

You review the patient and perform an ABG which reveals the following:

PaO2: 45 mmHg

pH: 7.51

PaCO2: 23.2 mmHg

HCO3-: 22 mEq/L

• Metabolic Alkalosis

• Respiratory Alkalosis with Metabolic Compensation

• Respiratory Alkalosis

• Metabolic Acidosis

Multiple Choice

A 24-year-old medical student has just returned from his elective in Ghana. In the last few days, he has developed severe diarrhea and has now presented to ED. On assessment, he is very dehydrated and tachypneic.

An ABG is performed and reveals the following:

PaO2: 109.5 mmHg

pH: 7.32

PaCO2: 30 mmHg

HCO3-: 13 mEq/L

• Respiratory Acidosis with Metabolic Compensation

• Metabolic Acidosis with Respiratory Compensation

• Metabolic Acidosis

• Respiratory Acidosis

Multiple Choice

A 64-year-old man is admitted to ED with central crushing chest pain. As the nurses are getting him attached to the ECG he has a cardiac arrest. Thankfully CPR was commenced immediately and after 6 minutes he regained spontaneous circulation and began breathing again.

An ABG (on 15L O2) performed following this sequence of events reveals the following:

PaO2: 71.3 mmHg

pH: 7.14

PaCO2: 60.8 mmHg

HCO3-: 15.2 mEq/L

• Metabolic Acidosis

• Respiratory Acidosis

• Mixed Respiratory and Metabolic Acidosis

• Respiratory Acidosis with Metabolic Compensation

Open Ended

Reflecting on today's lesson about acid-base balance, what is one question you still have or one concept you would like to explore further?