ABG Fundamentals (Mark K Lecture 1) Flashcards
pH
7.35-7.45
Partial pressure carbon dioxide
PaCO2
35-45
Bicarbonate
HCO3
22-26
Partial pressure oxygen
PaO2
75-100
Oxygen saturation
SaO2
≥ 95
What is the “Rule of B’s” when interpreting ABGs?
If the pH and the Bicarb are both in the same direction, then it is metaBolic
What ABG value determines if a patient has acidosis or alkalosis?
- Low pH = acidotic
- High pH = alkalotic
If both pH and Bicarb are both high or both low, what does that indicate?
Acidosis or Alkalosis condition is METABOLIC
If pH and Bicarb values are opposite each other (one high, one low) what does that indicate?
Acidosis or Alkalosis condition is RESPIRATORY
What is indicated if BiCarb (HCO3) is with normal range and pH is high or low?
- The acidosis/alkalosis is RESPIRATORY
- If BiCarb is normal or opposite of pH, it is always RESPIRATORY
Interpret the following values:
pH = 7.30, HCO3 = 20
- pH 7.30 ↓, HCO3 20 ↓
- Both pH an Bicarb are in the same direction (low), making it metabolic
- Low pH = acidosis
- Condition is: metabolic acidosis
Interpret the following values:
pH = 7.58, HCO3 = 32
- pH 7.58 ↑, HCO3 32 ↑
- Both pH and BiCarb are in the same direction (high), making it metabolic
- High pH = Alkalosis
- Condition is: Metabolic Alkalosis
You are providing care to a client with the following blood gas results: pH: 7.32, CO2: 49, HCO3: 29, PO2: 80, and SaO2: 90%. Based on these results, the client is experiencing:
- Respiratory Acidosis
- pH ↓, HCO3 ↑ = RESPIRATORY
- pH ↓ = ACIDOSIS
- Condition = RESPIRATORY ACIDOSIS
What are the four acid-base conditions?
- Metabolic Acidosis
- Metabolic Alkalosis
- Respiratory Acidosis
- Respiratory Alkalosis
The only acid base condition to cause Kussmaul respirations is?
Metabolic Acidosis
What are Kussmaul respirations?
a deep, rapid breathing pattern to expel carbon dioxide
As the _______ goes, so goes _______ except for _______. To what does this phrase refer?
- pH
- my patient
- Potassium
- This refers to pt s/s to pH levels
If pH is up, what are the s/s?
- Don’t memorize a list of s/s
- s/s will relate to elevated s/s
- ex: hypokalemia, alkalosis, HTN, Tachycardia, Tachypnea, Seizures, Irritability, Spastic, Diarrhea, borborygmi, hyperreflexia, etc
- Note that potassium is the opposite of all other s/s (hypokalemia)
If pH is low, what are the s/s?
- Don’t memorize a list of s/s
- s/s will relate to depressed s/s
- ex: hyperkalemia, acidosis, HTN, bradycardia, constipation, absent bowel sounds, flaccid, bradypnea
- Note that potassium is the opposite of all other s/s (hyperkalemia)
Causes of acid-base imbalance: First ask yourself, “Is it _______?” If yes, then it’s _______. Then ask yourself: “Are they _______ or _______. If _______, pick _______. If _______, pick _______
- lung
- respiratory
- over ventilating
- under ventilating
- over ventilating
- alkalosis
- under ventilating
- acidosis
What is respiratory rate vs ventilation?
- RR = speed of breathing
- Ventilation = actual O2sat
- You can breathe fast/slow and still not get enough O2 (proper ventilation)
Causes of acid-base imbalance: If it’s not lung, then it’s _______. If the patient has _______ _______ vomiting or suction, pick _______. For everything else that isn’t lung, pick _______ _______. When you don’t know what to pick, choose _______ .
- Metabolic
- prolonged gastric
- alkalosis
- metabolic acidosis
- metabolic acidosis
Ventilators:
High pressure alarms are triggered by _______ resistance to air flow.
Increased
Ventilators:
High pressure alarms are triggered by increased resistance to airflow and can be caused by obstructions of three types. Name the type and action to be taken to resolve each.
- Kinked tube: unkink
- Water in tube: empty
- Mucus in airway: cough and deep breathe
Ventilators:
Low pressure alarm are triggered by _______ resistance to airflow.
Decreased
Ventilators:
Low pressure alarms are triggered by decreased resistance to airflow and can be caused by disconnections of the _______ or _______. Give the action to be taken for each cause
- Tubing: reconnect it
- Oxygen sensor tube: reconnect it UNLESS tube is on the floor, then bag them and call the Rapid Response Team (RT) if this happens
Ventilators:
Respiratory alkalosis mean ventilator settings may be too _______.
High (overventilation)
Ventilators:
Respiratory acidosis mean ventilator settings may be too _______
Low (underventilation)
Ventilators:
What does “wean” mean?
gradually decrease with the goal of getting off altogether
Under which acid-base condition would we NOT take the pt off the ventilator and why?
Respiratory acidosis, due to UNDERVENTILATION
Under which acid-base condition would we be able to take the pt off the ventilator and why?
Respiratory alkalosis, due to OVERVENTILATION
What are the value ranges for reflexes?
- 0-1 = hyporeflexia
- 2 = normal
- 3-4 = hyperreflexia
What are borborygmi?
Increased bowel sounds
On the NCLEX, what is the general rule of thumb regarding how many answers to select on a SATA question?
- The answer is never just one
- The answer is never all
Why do we NOT memorize lists such as s/s of a condition?
because all books/classes have different lists
How do we know which s/s to choose in a list? Give an example.
- Know principles of how a condition affects the body and then choose options (generate a list) of s/s that relate to that
- Ex: Opioids/pain meds:
- sedation, CNS depression -> lethargy, flaccidity, +1, hyporeflexia, obtunded
- Any s/s that are presented that support this line of affect
In our NCLEX style questions, we need to pay more attention to the modifying phrases than the original noun. Give two examples of this.
- Person w/ OCD who is now psychotic (psychotic trumps OCD)
- Hyperemesis with dehydration (pay attention to dehydration)
