Acid-Base Disorders Flashcards

Question

Metabolic acidosis

Answer 1

The process that results in the gain of hydrogen ions (H+) or the loss of HCO3 **Net gain of hydrogen ions:** ↑ acid production lactic acidosis, ketoacidosis, toxic alcohols (methanol, ethylene glycol), medications (ASA overdose, chronic acetaminophen usage) Impaired excretion Renal tubular acidosis, renal failure **Loss of HCO3** Diarrhea (direct loss in stool), renal tubular acidosis (loss in urine), carbonic anhydrase inhibitors (stops reabsorption in the proximal tubule, so loss in urine)

Answer 2

pH ↓ HCO3 ↓ Partial pressure of arterial CO2 (PCO2) ↓ **Think: “So the acidosis is NOT due to ↑ CO2; it must be due to ↓ serum HCO3”** Confirm by looking at HCO3 → will be low (< 22 mEq/L) Compensation: In primary **metabolic** acid-base disorders, the **lungs may try to compensate** in an attempt to normalize the pH Lungs respond to metabolic **acidosis by ↑ ventilation (hyperventilation)**

Answer 3

Symptoms may include: * **Kussmaul respirations (rapid, deep, labored breathing)** * Diarrhea- increased loss of bicarb * Ketoacidosis: Polyuria Polydipsia Epigastric pain Vomiting * Renal failure Dehydration Fluid overload Pruritis Oliguria Methanol poisoning: visual symptoms (photophobia, blindness) * Salicylate overdose: Tinnitus Blurred vision Vertigo

Answer 4

Directed at correcting the underlying etiology Example: For ketoacidosis, give insulin and correct fluid and electrolyte abnormalities **Consider giving HCO3 if: Acidosis is severe (pH < 7.1) The patient has severe kidney injury**

Answer 5

The process that results in a decreased level of carbon dioxide (CO2) within the blood

Answer 6

Anxiety/hyperventilation Etiology: Physiologic Pregnancy High altitude Medications Aspirin overdose Nicotine overdose Hypoxia-induced PE Pulmonary edema Intracranial process Stroke TBI Encephalitis Psychologic Anxiety Psychosis

Answer 7

pH ↑ PCO2 ↓ Compensation: In primary **respiratory** acid–base disorders, the **kidney may try to compensate** in an attempt to normalize the pH Kidneys respond to respiratory alkalosis by decreasing serum HCO3– through: ↓ Secretion of H+ Urinary excretion of HCO3 (normally bicarbonate is 100% absorbed)

Answer 8

Tachypnea Dyspnea Dizziness/light-headedness Paresthesias (perioral, hands/feet) due to decreased ionized calcium Psychologic symptoms: Anxiety Fear Impending doom

Answer 9

Assess and address the ABCs (airway, breathing, and circulation) if patient is in acute distress Attempt to correct the underlying abnormality Small dose of short-acting benzodiazepine to help with psychologic symptoms

Answer 10

The process that results in an accumulation of carbon dioxide (CO2) due to abnormal gas exchange in the lungs

Answer 11

* Decreased respiratory rate OSA, medications: opiates, benzodiazepines * Decreased tidal volume Cervical spine injuries above C3, muscular dystrophy, kyphoscoliosis, obesity * Severe ↓ lung diffusion capacity Emphysema, interstitial lung diseases, pulmonary fibrosis * Severe ventilation–perfusion mismatch Asthma, COPD, cystic fibrosis, interstitial lung diseases, pulmonary hypertension

Answer 12

pH ↓ PCO2 (partial pressure of carbon dioxide) ↑ (hypercapnia) Compensation: In primary respiratory acid–base disorders, the kidney may try to compensate in an attempt to normalize the pH Kidneys respond to respiratory acidosis by increasing serum HCO3 through ↑ secretion of H+

Answer 13

Presentation of hypercapnia: Neurologic: Anxiety/paranoia Headaches Somnolence Delirium Coma Pulmonary: Dyspnea

Answer 14

Assess the ABCs: Ensure that the airway is secure Administer supplemental O2 Ventilatory support as needed Treat the underlying etiology Examples: COPD exacerbation: bronchodilators and corticosteroids Pneumonia in neuromuscular disorders: antibiotics Avoid respiratory sedatives

Answer 15

Most common acid-base disturbance in hospitalized patients (ICU patients) Process that results in the loss of hydrogen ions (H+) or the gain of HCO3

Answer 16

* **Upper GI losses of hydrogen ions: Vomiting and/or nasogastric suctioning** * **↑ Renal losses of hydrogen ions:** Mineralocorticoid excess: Primary hyperaldosteronism Cushing's syndrome **Loop or thiazide diuretics** ↑ distal tubular delivery of Na+ → ↑ distal secretion of H+ and K+ * **↑ HCO3 intake:** Ingestion of non-absorbable antacids (calcium carbonate) or sodium bicarbonate pills * **Contraction alkalosis:** Decreased extracellular volume + stable HCO3 = ↑ HCO3 concentration

Answer 17

pH ↑ Partial pressure of CO2 (PCO2) ↑ HCO3 ↑ **Think: “So the alkalosis is NOT due to ↓ CO2; it must be due to ↑ serum HCO3” Confirm by looking at HCO3→ will be high (> 28 mEq/L)** Compensation: In primary **metabolic** acid-base disorders, the **lungs may try to compensate** in an attempt to normalize the pH Lungs respond to metabolic **alkalosis by ↓ ventilation**

Answer 18

If urine chloride < 10 mEq/L Etiologies: Vomiting Nasogastric suctioning Diuretics Volume depletion Laxative abuse chloride unresponsive **ABCD** If urine chloride >20 mEq/L Etiologies: Aldosteronism (primary) – Conn syndrome Bartter’s syndrome Cushing’s syndrome Depletion of magnesium

Answer 19

Symptoms may include: Vomiting BP abnormalities: Hypertension (primary mineralocorticoid excess) Hypotension (↓ effective circulating volume) Hypokalemia Hypocalcemia: Tetany Chvostek sign: contraction of facial muscles when the facial nerve is tapped Trousseau sign: carpopedal spasm with inflation of the BP cuff Changes in mental status/seizures | Alkalosis promotes the binding of calcium to albumin and can reduce the

Answer 20

Directed at correcting the underlying etiology Attempt to improve renal HCO3- excretion to resolve alkalosis: In patients without edema (true volume depletion): **volume repletion with isotonic saline** In patients with ↓ effective circulating volume (CHF, cirrhosis, renal artery stenosis): Potassium chloride K+-sparing diuretics Avoid isotonic saline as it will worsen symptoms without improving alkalosis

Acid-Base Disorders Flashcards

(48 cards)