Exam 2 (ABG) Flashcards
Alkalemia is the excessive production of?
OH⁻ (in relation to hydrogen ions)
Bicarb enters and leaves the body via?
The proximal tubules
H⁺ is reabsorbed via?
The distal tubules & collecting ducts
CO₂ enters leaves the body via?
The lungs
If PaCO₂ & HCO₃⁻ change in the same direction then?
It’s a primary disorder with secondary compensation
If someone’s PaO₂ on room air is 75 then on 100% it should be?
375 - 500 (Factor of 5)
What are the consequences of acidosis on the CV system?
- Impaired contractility
- Decreased arterial BP
- Increased sensitivity to dysrhythmias
- Decreased response to catecholamines
- Decreased threshold for V-fib
At what pH does reduced catecholamine response happen?
At 7.1
What are the consequences of acidosis on the nervous system?
- Obtundation
- Coma
What are the consequences of acidosis on the pulmonary system?
- Hyperventilation
- Dyspnea
- Respiratory muscle fatigue
What are the consequences of acidosis on metabolism?
- Hyperkalemia
- Insulin resistance
- Inhibition of anaerobic glycolysis (decreased glucose production)
What is a flail chest?
Multiple broken ribs in various places
What are the 3 categories for respiratory acidosis?
- Central ventilation control (brain)
- Peripheral ventilation control (neuromuscular)
- V/Q mismatch (respiratory)
What happens to bicarb & PaCO₂ in acute hypercarbia?
- Bicarb rises slowly over 2-3 days
- PaCO₂ increases
What does a PaCO₂ to Bicarb ratio of 10 : 1 mean?
The kidneys are compensating
What would the PaCO₂ to Bicarb ratio be for chronic hypercarbia?
10 : 3
A Pt’s PaCO₂ is 80 mmHg, what is the expected HCO₃⁻?
28 mmHg
(PaCO₂ is 40 mm higher than normal; apply 10 : 1 rule; then HCO₃⁻ should increase 4 meq/L)
What happens to calcium in metabolic acidosis?
An increase in ionized calcium
A left shift of the oxyhemoglobin curve is associated with?
- Decreased PCO₂
- decreased H⁺
- decreased 2,3-DPG
- decreased temp
- HbF
A right shift of the oxyhemoglobin curve is associated with?
- Increased PCO₂
- Increased H⁺
- Increased 2,3-DPG
- Increased temp
If Bicarb is 12 mml/L then what is the expected PaCO₂?
- 26 mmHg
- 1.5 x 12 + 8= 26
- 1.5 x HCO₃⁻ + 8
Bicarb loss is compensated with?
A net gain of chloride ions
What are causes metabolic acidosis with a normal anion gap?
- Sodium chloride infusions
- Diarrhea
- Early renal failure
What are causes for metabolic acidosis with a high anion gap?
- Lactic- & Ketoacidosis
- Renal failure
- Poisonings
What happens in the extacellular space with a high anion gap?
H⁺ combines with HCO₃⁻ leading to decreased bicarb availability
What is the formula for calculating the anion gap?
- Na⁺ - (Cl⁻ + HCO₃⁻) = 12 - 14 mEq/L
What conditions complicate the anion gap?
- Hypoalbuminemia
- Hypophosphatemia
- Both are negatively charged
How is metabolic acidosis treated?
Treat the underlying cause
What is the formula correcting acidosis with bicarb?
0.3 x base deficit (mmol/L) x kg
What are causes for respiratory alkalosis?
- Anxiety
- pregnancy
- salicylate overdose
- hyperventilation
What are the symptoms of respiratory alkalosis?
- Lightheaded
- visual disturbances
- dizziness
What happens to calcium in respiratory alkalosis?
It binds to albumin more readily
What is Trousseau’s sign?
Hand cramping when BP is inflated on the arm
What is Chvostek’s sign?
Irritability with taps on the facial nerve
How many branches are the for the facial nerve?
5
What are the branches of the facial nerve?
top to bottom:
- frontal (or temporal),
- zygomatic,
- buccal,
- marginal mandibular,
- cervical.
What is metabolic alkalosis also called?
Volume depletion or volume overload alkalosis
What are the causes of metabolic alkalosis?
- Hypovolemia
- vomiting
- NG suction
- diuretic therapy
- Bicarb administration
- Hyperaldosteronism
How is metabolic alkalosis treated caused by vomiting or NG suction?
PPI’s
How is volume overload alkalosis treated?
K⁺ sparing diuretics
