chapter 48 quiz 1 Importance of Acid-Base Balance

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What is the negative logarithmic value of hydrogen ion concentration typically measured as?

pH (correct)

Acid power

Alkaline concentration

Hydrogen power

What is the resting value of extracellular pH?

6.8

7.4 (correct)

5.6

8.2

In the context of acid-base balance, what process impact the water to auto-ionize into hydrogen and hydroxyl ions?

Deviations in extracellular pH

Tight control of electrolyte composition

Alterations in the relative concentrations of electrolytes and carbon dioxide (correct)

Changes in the local concentration of O2

changes in the local concentration of strong ions, weak acids, and CO2 lead to ?

Acid-base abnormalities Signup and view all the answers

Which equation represents the Henderson-Hasselbalch equation for acid-base balance?

pH=6.1 + log [HCO3]/PCO2 ×0.03 Signup and view all the answers

What is the structural formula of water?

H-O-H Signup and view all the answers

Why is water considered neutral?

Equal concentration of hydrogen ions and hydroxyl ions Signup and view all the answers

In the context of acid-base chemistry, what does Brønsted-Lowry define an acid as?

A proton donor Signup and view all the answers

In the context of acid-base chemistry, what does Brønsted-Lowry define an base as?

A proton acceptor Signup and view all the answers

What is the consequence when the concentration of hydrogen ions increase?

Decrease in hydroxyl ion concentration Signup and view all the answers

Lactic acid is a

strong acid Signup and view all the answers

carbonic acid is a

Its pKa value of 6.4 Signup and view all the answers

Which of the following ions are considered strong ions?

Sodium (Na+), potassium (K+), and chloride (Cl−) Signup and view all the answers

In the context of the text, what function do all cations serve?

Function as bases Signup and view all the answers

Why is the delivery of hydrogen moiety into extracellular fluid by Cl− significant?

It acts as an acid Signup and view all the answers

What role does water play in the reaction NaOH + H2O→H2O + OH− + Na+

Water acts as acid Signup and view all the answers

What role does water play in the reaction HCL + H2O→H3O+ + Cl−?

Water acts as a base Signup and view all the answers

How do the hydrogen and hydroxyl ions delivered by Cl− and Na+ ultimately form?

They form water molecules Signup and view all the answers

What principle must be followed in acid-base reactions to ensure that the sum of all positive ions equals the sum of all negative ions in a compartment?

Electrical neutrality Signup and view all the answers

What is the term used to describe substances that dissociate completely ?

Strong ions Signup and view all the answers

Which ion is mentioned as one of the most abundant strong ions in the extracellular space?

Na+ and Cl−. Signup and view all the answers

why strong ions are occasionally referred to as “mineral” acids or bases ?

cannot be metabolized Signup and view all the answers

Which rule states that the total concentration of an incompletely dissociated substance is the sum of concentrations of its dissociated and undissociated forms?

Mass conservation Signup and view all the answers

In acid-base chemistry, what significance do strong cations and strong anions carry?

They contribute to charge balance Signup and view all the answers

What independently influences the hydrogen ion concentration in a solution ?

SID Signup and view all the answers

In human ECF, SID is always?

positive Signup and view all the answers

Any change in SID will change ?

[H+] and [OH−] concentrations. Signup and view all the answers

what is the relationship betweeb [H+]and [OH−]

inverse Signup and view all the answers

Which variable is considered independent in the equations involving SID and ATOT?

SID and ATOT Signup and view all the answers

Which compound exists in multiple forms in extracellular fluid along with CO2(d)?

[HCO3−] Signup and view all the answers

In the context of weak acid 'buffer' solutions, which molecule influences acid-base balance?

Albumin and phosphate. Signup and view all the answers

What does Stewart's term ATOT represent in the context of acid-base balance?

Total concentration of weak acids Signup and view all the answers

What determines the concentration of CO2(d) in the extracellular fluid?

solubility coefficient of CO2 Signup and view all the answers

What is a simple rule of thumb for acute respiratory alkalosis?

ΔHCO3- = 0.2 ΔPaCO2 Signup and view all the answers

Which symptom is associated with hyperventilation in a patient with acute respiratory alkalosis?

Hypocalcemia Signup and view all the answers

In respiratory alkalosis, how does the pH compare to normal?

pH > 7.45 Signup and view all the answers

What characterizes acute respiratory alkalosis in terms of PaCO2 and HCO3−?

Low PaCO2, low HCO3− Signup and view all the answers

What is the normal value of PaCO2 in arterial blood?

40 mm Hg Signup and view all the answers

What is the main cause of hypocalcemia in a patient with acute respiratory alkalosis?

Increase in albumin binding to calcium Signup and view all the answers

What is the main compensatory mechanism for metabolic alkalosis mentioned in the text?

Hypoventilation Signup and view all the answers

What is the result of a decrease in the SID as per the text?

Acidemia Signup and view all the answers

Which scenario may lead to a reduction in the SID and dilutional acidosis according to the text?

Expansion of the extracellular compartment with free water Signup and view all the answers

What clinical significance does metabolic acidosis have according to the text?

vasodilation and decreased muscular performance Signup and view all the answers

In metabolic alkalosis, what symptoms and signs are mentioned in the text?

Tetany and paresthesia Signup and view all the answers

What happens to blood pH in metabolic acidosis compared to respiratory acidosis as per the text?

Blood pH falls less in metabolic acidosis Signup and view all the answers

What is The most significant form of metabolic acidosis ?

net gain of unmeasured anions Signup and view all the answers

In hospital medicine, what solution containing 154 mEq of sodium and 154 mEq of chloride is commonly used?

Normal saline (NaCl 0.9%—NS) Signup and view all the answers

What causes metabolic alkalosis due to an increase in SID?

Vomiting Signup and view all the answers

Which of the following is NOT a cause of acidosis according to the text?

Excessive sodium intake Signup and view all the answers

What is also important determinant of acid-base status ?

Serum albumin and phosphate Signup and view all the answers

What impact does hyperphosphatemia have on the acidosis of renal failure?

It worsens the acidosis Signup and view all the answers

What happens when hypoalbuminemia decreases ATOT?

It causes metabolic alkalosis Signup and view all the answers

'Contraction alkalosis' is commonly seen in clinical practice following the administration of which type of diuretics?

'Loop diuretics' Signup and view all the answers

'Metabolic alkalosis' is caused by chloride loss obeying which principle mentioned in the text?

'Law of conservation of mass' Signup and view all the answers

'Hypoalbuminemia' is associated with a strong relationship with which aspect mentioned in the text?

Severity of critical illness Signup and view all the answers

What is the main reason why therapeutic hyperventilation is no longer used to treat intracranial hypertension?

Risk of cerebral hypoperfusion and ischemia Signup and view all the answers

Which condition is associated with problems in central ventilator control according to the text?

Stroke Signup and view all the answers

What clinical signs are indicative of respiratory acidosis?

Cyanosis and vasodilatation Signup and view all the answers

What does an increase in PaCO2 by 10 mm Hg result in during acute Respiratory Acidosis ?

Increase in HCO3− by 1 mmol/L Signup and view all the answers

Respiratory Acidosis occurs when there is an acute rise in PaCO2 usually associated with respiratory failure. This may result from problems with?

Central ventilator control duo to stroke, spinal cord injury Signup and view all the answers

Why might a patient fail to liberate from mechanical ventilation due to acute metabolic alkalosis?

hypoventilation Signup and view all the answers

Which intravenous fluid could impact postoperative CO2-HCO3− homeostasis based on the information provided?

Isotonic saline solution Signup and view all the answers

In the context of acute respiratory distress syndrome (ARDS), what is preferred?

'Permissive' hypercapnia is preferred Signup and view all the answers

In anesthesia practice, patients may hyperventilate preoperatively and develop Respiratory Alkalosis as a consequence of ?

anxiety Signup and view all the answers

In anesthesia practice, patients may hyperventilate postoperatively and develop Respiratory Alkalosis as a consequence of ?

full bladder Signup and view all the answers

Respiratory Alkalosis due to hyperventilation More commonly results from

poor mechanical ventilation strategy Signup and view all the answers

Compensation for hypercarbia due to Respiratory Acidosis is

slow, requiring increased urinary excretion of Cl− Signup and view all the answers

Compensation for hypercarbia due to Respiratory Acidosis result in

increase in the plasma HCO3− occurs and reflects a higher total CO2 load. Signup and view all the answers

“rules of thumb In acute hypercarbia (acute Respiratory Acidosis ) is:

An increase in PaCO2 by 10 mm Hg (1.3 kPa) results in an increase in HCO3− by 1 mmol/L (1 mEq/L) Signup and view all the answers

what is the expected HCO3 for A patient returning to the ICU from the operating room, with a PaCO2 of 80 mm Hg ?

28 mmol/L Signup and view all the answers

In chronic respiratory failure, the total CO2 load in the body increases substantially, reflected by

high levels of plasma HCO3−. Signup and view all the answers

In chronic respiratory failure There is a concomitant fall in plasma ?

plasma chloride, reflecting compensation for elevated levels of carbonic acid. Signup and view all the answers

rules of thumb In chronic Respiratory Acidosis

An increase in PaCO2 by 10 mm Hg (1.3 kPa) will increase plasma [HCO3−] by 3 mmol/L (3 mEq/L) Signup and view all the answers

A patient returning to the intensive care unit from the operating room, ventilated to a PaCO2 of 40 mm Hg but with high total CO2, secondary to chronic respiratory failure ( COPD). the preoperative baseline of total CO2 is 33 mEq/L. what is the PaCO2 baseline

PaCO2 of 70 mm Hg Signup and view all the answers

A useful rule of thumb used to characterize metabolic acidosis?

for every 1 mEq/L fall in the SID, there is a 1 mEq/L fall in the [HCO3−] from baseline Signup and view all the answers

The body is hyperresponsive to acidosis. Increasing hydrogen ion content in cerebrospinal fluid lead to

reducing Bicarbonate concentration Signup and view all the answers

In normal ECF, the SID is 40 to 44 mEq/L, this positive charge being balanced principally by weak acids which without it the PH will be

11.9 Signup and view all the answers

Albumin deficits can result from ?

capillary leak with loss of albumin into the interstitium; Signup and view all the answers

the presence of hypoalbuminemia may mask the detection of acidosis caused by?

unmeasured anions Signup and view all the answers

What is the role of a buffer in maintaining pH balance?

Minimization of changes in pH Signup and view all the answers

How does deoxygenated hemoglobin contribute to acid-base balance?

It buffers volatile acids Signup and view all the answers

Which of the following is the primary source of acid in the body?

Volatile acid CO2 Signup and view all the answers

What happens when carbon dioxide combines with water within erythrocytes?

Formation of bicarbonate ions Signup and view all the answers

How is the regulation of hydrogen ion concentration primarily achieved ?

Binding by hemoglobin Signup and view all the answers

Why is it important for a buffer to have a pKa close to the physiological pH range?

To prevent rapid changes in pH Signup and view all the answers

What effect does respiratory failure have on the principal CO2 buffering system?

It overwhelms the buffering capacity of Hb Signup and view all the answers

Which process is conventionally referred to as 'metabolic compensation'?

The maintenance of ECF osmolality through NH4+ usage Signup and view all the answers

What is the result of compensation for chronic hypercarbia due to respiratory acidosis?

A rightward shift in the PCO2 response curve Signup and view all the answers

What is the role of carbonic anhydrase?

conversion of CO2 to HCO3 Signup and view all the answers

How is metabolic acid buffered in the body?

By retaining weak acids in plasma Signup and view all the answers

What characterizes renal tubular acidosis in terms of Cl− excretion?

Inability to excrete Cl− in proportion to Na+ Signup and view all the answers

How does pseudohypoaldosteronism primarily impact chloride reabsorption?

By promoting high reabsorption of Cl− over Na+ Signup and view all the answers

What is the significance of the bicarbonate buffering system in extracellular buffering?

It accounts for 13% of overall extracellular buffering Signup and view all the answers