Exam 3: Acid Base

Question 1

Obtaining Arterial Blood Gas (ABG)

Answer 1

Arterial puncture, usually radial

Perform Allen’s Test to ensure adequate ulnar blood flow when using radial artery

Record supplemental O2 and/or ventilator settings on specimen

Specimen placed on ice and taken to lab

Apply pressure for 5-10 minutes and watch for bleeding, may be longer if PT on anticoagulants

Question 2

pH (7.35-7.45)

Answer 2

<7.35 = acidosis
>7.45 = alkalosis

Indicator of H+ ion concentration and measures acidity/alkalinity of blood

Question 3

CO2 (35-45 mmHg)

Answer 3

Respiratory

Controlled by lungs through the medulla

When CO2 is increased, drive to breathe occurs, potential acid

Question 4

HCO3 (22-26 mEq/L)

Answer 4

Metabolic

Regulated by kidneys

Excrete or reabsorb ions needed to balance pH

Question 5

PaO2 (80-100)

Answer 5

Measure of oxygen in arterial blood, different from SpO2

Question 6

ROME

Answer 6

Respiratory = Opposite

Metabolic = Equal

Question 7

Compensation

Answer 7

Unaffected system will try to balance to compensate for the system out of sync

If pH and CO2 OR HCO3 is out of sync = uncompensated

If pH and both CO2 and HCO3 are out of sync (all three) = partially compensated

If pH is NORMAL and BOTH CO2 and HCO3 are out of sync = fully compensated

Question 8

Metabolic acidosis

Answer 8

Causes: Lactic acidosis, diarrhea

Manifestations: Headache, confusion, increased respiratory rate/depth, shock if pH drops below 7

Treatment: Treat underlying cause, follow K+ levels closely, hemodialysis/peritoneal dialysis

Compensation: Compensatory mechanisms increase ventilation rate and the renal retention of bicarbonate

Question 9

Metabolic alkalosis

Answer 9

Causes: Vomiting, loss of K+

Manifestations: Hypocalcemia symptoms, lungs slow respiratory rate to compensate, kidneys will excrete more HCO3 if able

Treatment: Treat underlying cause, normal saline solution IV fluids, K+ for hypokalemia

Compensation: Respiratory system compensates by decreasing ventilation to conserve CO2 and increase PaCO2

Question 10

Respiratory acidosis

Answer 10

Causes: Inadequate excretion of CO2, pulmonary complications (COPD), overdose of sedatives

Manifestations: Acute: Change in MS, hyperkalemia
Chronic: Asymptomatic unless CO2 increases rapidly

Treatment: Improve ventilation (medications, intubation/bipap, hydration)

Compensation: Excess hydrogen is excreted in urine in exchange for bicarbonate ions

Question 11

Respiratory alkalosis

Answer 11

Causes: Hyperventilation
Acute: Anxiety, hypoxemia, early sepsis
Chronic:* Hepatic insufficiency, cerebral tumors

Manifestations: Lightheadedness, change in MS, tachycardia, arrhythmias

Treatment: Treat underlying cause

Compensation: Renal excretion of bicarbonate increases and hydrogen ions are retained

Question 12

Hypoxia

Answer 12

Give oxygen

Treat underlying cause

Question 13

Nursing interventions for acid-base imbalances

Answer 13

Be aware of signs and symptoms

Understand treatments

Provide supportive care to patients and families