Acid/Base- SG Flashcards

1
Q

ABGs are frequently used to detect and monitor indices of what 3 things?

A
  • Oxygenation
  • Ventilation
  • Acid-base balance
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2
Q

ABGs quantify levels of _____ & ______.

A
  • carboxyhemoglobin
  • methemoglobin
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3
Q

ABG

  • Blood is drawn usually from what artery?
  • Sometimes drawn from what other 2 arteries?
  • Blood is collected with _____ and placed on ice and taken quicky to lab for prompt analysis
  • Results are usually back within _____.
A
  • Radial
  • Brachial or femoral aa
  • anticoagulant (heparin)
  • 5 - 15 mins
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4
Q

Oxygenation

  • The pO2 is just used in determining ____.
  • NOT in the determination of _____.
  • Is pO2 from ABG or pulse ox more reliable way to check oxygenation?
A
  • How well pt is oxygenating
  • NOT: acid base conditions
  • pO2 from ABG is more reliable than pulse ox.
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5
Q
  • Body maintains precise control of ____ to maintain homeostasis
  • ____ are used to keep pH in narrow range.
A
  • Hydrogen ions
  • Buffer systems
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6
Q
  • Acidemia is pH
  • Alkalemia is pH >____
A
  • <7.35
  • >7.45
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7
Q

pH of blood

A

Acidemia & Alkalemia

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8
Q

Acid/Base Disorder

A

Acidosis & Alkalosis

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9
Q

Tx for acid/base disturbances?

A

Management of underlying disease

(can have up to 3 disorders)

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10
Q
  • 2 types of compensation for acid/base disorders?
  • Which one is rapid and which is slow?
A
  • Respiratory compensation (rapid)
  • Metabolic compensation (days - weeks)
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11
Q

Acid/Base

  • A primary respiratory problem involves ___
  • If greater than ___ is acidosis
  • If less than ____ is alkalosis
A
  • pCO2
  • >45 = acidosis
  • <35 = alkalosis
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12
Q

Acid/Base

  • Primary metabolic problem involves ____.
  • If greater than ___ is alkalosis
  • If less than ____ is acidosis
A
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13
Q
  • pH: >7.45
  • Disturbance: decreased pCO2 (<35)
  • Secondary response: decreased HCO3
A

Respiratory Alkalosis

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14
Q
  • pH: >7.45
  • Disturbance: increased HCO3 (>26)
  • Secondary response: increased pCO2
A

Metabolic Alkalosis

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15
Q
  • pH: <7.35
  • Disturbance: increased pCO2 (>45)
  • Secondary response: increased HCO3
A

Respiratory acidosis

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16
Q
  • pH: <7.35
  • Disturbance: decreased HCO3 (<22)
  • Secondary response: decreased pCO2
A

Metabolic acidosis

17
Q

If both pCO2 and HCO3 are HIGH, what could it be?

A
  • Respiratory acidosis
  • Metabolic alkalosis
18
Q

If both pCO2 and HCO3 are LOW, what could it be?

A
  • Respiratory alkalosis
  • Metabolic acidosis
19
Q

If pCO2 and HCO3 are moving in opposite directions, there is what?

A

Mixed disorder is present

20
Q

What causes high anion gap metabolic acidosis?

A
  • Methanol
  • Uremia
  • DKA
    Propylene glycol
  • Iron/Isoniazid
  • Lactate
  • Ethanol/ethylene glycol
  • Salicylates/starvation

(MUDPILES)

21
Q

Causes of non-anion gap metabolic acidosis

A
  • GI bicarbonate loss
  • Renal bicarbonate losses
  • Hyperchloremia due to saline resuscitation
22
Q

Tx of Metabolic Acidosis

  • Consider giving _____ to help w/ immediate period until you’ve treated the underlying cause
  • Allow for ______.
    • Pts will be _____ in order to compensate, so avoid giving certain meds
A
  • Sodium bicarbonate
  • Respiratory compensation
  • Hyperventilating, so don’t give meds which depress their resp drive
23
Q

If urine chloride <25 = ____ responsive metabolic alkalosis

  • 3 causes
  • HCO3 >___
  • Tx?**
A

<25

  • GI losses
  • Diuretics (contraction alkalosis)
  • Cystic fibrosis
  • Tx w/ FLUIDS!!
24
Q

If urine chloride >25 = _____ responsive metabolic alkalosis

  • 7 causes?
  • Tx?
A

Non-chloride responsive metabolic alkalosis

  • Barter’s syndrome
  • Cushing’s
  • Hyperaldosteronism
  • K depletion
  • Citrate toxicity for massive blood transfusion protocol
  • Chronic diuretics
  • Renin secreting tumor
  • Tx underlying cause, may need potassium
25
Q

Acidosis or Alkalosis?

  • Hyper-ventilation
  • Shift of oxy-hemoglobin dissociation curve
  • Myocardial depression
  • Sympathetic overactivityy (tachycardia, vasoconstriction, increased arrhythmias)
  • Resistance to catecholamines
  • Peripheral arteriolar vasodilation
A

Acidosis

26
Q

Acidosis or Alkalosis?

  • Peripheral venoconstriction
  • Pulmonary artery constriction
  • K shift out of cells (effect on myocytes)
  • Cerebral vasodilation, increased ICP
  • Central depression w/ high pCO2
A

Acidosis

27
Q

Acidosis or Alkalosis?

  • Decreased respiratory drive
  • Shift of oxyhemoglobin curve (impaired O2 unloading)
  • Depression of myocardial contractility
  • Arrhythmias
  • K shift into cells (hypokalemia)
  • Cerebral vasoconstriction –> dec in cerebral blood flow
  • Increased NM excitability
A

Alkalosis

28
Q

Essentially not able to ventilate well enough, leading to an accumulation of CO2 (>45)

  • 4 causes
A

Respiratory Acidosis

  • Acute airway obstruction
  • Lung disease
  • CNS depression
  • Neuromuscular disorder
29
Q

Tx for Respiratory Acidosis

A
30
Q

Excessive elimination of CO2 from lungs

“blowing off too much CO2”

  • CO2
  • 4 sxs?
A

Respiratory Alkalosis

  • CO2 <35
  • Lightheadedness
  • Palpitations
  • Tachypnea
  • +/- parasthesias
31
Q

Most common cause of Respiratory Alkalosis?

A

Hyperventilation (anxiety is MC)

  • Compensatory mechanism in sepsis
  • Pain
  • CNS (neurogenic hyperventilation)
  • Salicylate overdose
  • Pregnancy
  • High altitude
  • Hypoxemia
  • Hepatic encephalopathy
32
Q

Tx for Respiratory Alkalosis?

A

Tx underlying cause

33
Q

T/F

  • The body does not fully compensate for primary acid-base disorders
A

True

34
Q

If pCO2 and HCO3 go in opposite directions, you likely have multiple disorders.

  • Always focus on which value first in this case?
A

HCO3

35
Q

Anytime you have a very high anion gap (AG>___), there automatically has to be ______, regardless of pH or serum bicarbonate concentration.

A
  • AG>20
  • primary metabolic acidosis
36
Q

T/F

  • The body generates a large anion gap to compensate for a primary disorder
A

False

The body DOES NOT generate a large anion gap to compensate for primary disorder

37
Q

Mixed Acid-Base Disorders

  • You can have up to ___ different disorders at a time
  • You can have ___ & ____ at same time
  • You can have only ONE ____ disorder
  • What 2 things help you determine mixed disorders?
  • Tx should always be directed at what?
A
  • 3
  • Metabolic alkalosis & Metabolic acidosis
  • Respiratory disorder
  • Anion & Delta gap calculations
  • Cause of the primary disorder
38
Q

Take home points

  • A normal pH does not mean there is not an acid/base disorder
  • Can have ____ acidosis & alkalosis at same time!
  • _____ is usually pathologic (investigate!!)
A
  • Metabolic
  • Low bicarbonate