| What is the acid base disorder if the results are as follows:
pH:7.50
pCO2: 36 minutes
HCO3: 33 mEq/ | metabolism alkalosis |
| What is the acid base disorder if the results are as follows:
pH:7.28
pCO2: 47 mmHg
HCO3: 24 mEq/ | respiratory acidosic |
| • Is a substance that can yield a hydrogen ion (H+) or hydronium ion when dissolved in water
• Can donate hydrogen ions | Acid |
| • Is a substance that can yield hydroxyl ions (OH-)
• Can accept hydrogen ions | Base |
| • negative log of the hydrogen ion concentration | PH of solution |
| • a decrease in one pH unit represents a | 10-fold increase in H+ concentration. |
| • Relatively strengths of acids and bases their ability to dissociate in water | Dissociation Constant (K value) |
| • Negative log of dissociation constant
• Also known as Ionization constant | pKa |
| • Have pK values of less than 3.0
• Raising the pH above pK will cause it to dissociate and yield a H+ | Strong Acids |
| • Have a pK values of greater than 9.0
• Lowering the pH below the pK will cause it to release OH- | Strong bases |
| • Combination of a weak acid or weak base and its salt, and it resists the change in pH upon adding acid or base. | Buffer |
| • Bicarbonate-Carbonic Acid – pK of | 6.1 |
| is a weak acid because it does not completely dissociate into H+ and HCO3– | Bicarbonate |
| is a strong acid because it completely dissociates into H+ and Cl– in solution | HCL |
| • Not a measure of CO2 concentration in the blood
• 35 - 45 mmHg | Partial Pressure of CO2 (pCO2) |
| • Refers to the total concentration of CO2 in the blood
• Consisting of ionized (HCO3, CO3, carbamino compound) and unionized fraction (H3CO3) and physically dissolved CO2
• 23 – 27 mmol/L | Total Carbon Dioxide Concentration |
| has been equilibrated with CO2 at 40mm Hg at 37 degrees Celsius
• 22 – 26 mmol/L | Bicarbonate Ion Concentration |
| • Normal pH of blood | 7.35 – 7.45 (Average 7.4) |
| • To change 100 mL of normal blood from a pH of 7.35 to a pH of 7.0, | 25 mL of 0.05 N HCL is needed |
| • With 5.5 L of blood, more than | 1300 mL of HCL would be required to make this same change in pH |
| • Through metabolism, the body produces approximately | 150 g of H+ each day. |
| • The body controls and excretes H+ in order to | maintain pH homeostasis |
| • < 7.35 | Acidosis |
| • >7. 45 | Alkalosis |
| When an acid is added, HCO3 will combine with the | H+ from the H2CO3 |
| When a strong base is added, H2CO3 will combine with the | OH– ions to form H2O and the weaker conjugate base HCO3–. |
| involved in buffering, primarily in the intracellular fluids and to a minor extent in the extracellular spaces | Proteins and phosphates |
| The most important buffer system in extracellular fluids for three reasons
1. H2CO3 dissociates into CO2 and H2O, allowing CO2 to be eliminated by the lungs and H+ as water
2. Changes in CO2 modify the ventilation (respiratory) rate
3. HCO3– concentration can be changed by the kidneys. | True |
| primary buffer in urine and is involved in the exchange of sodium ion in the urine filtrate | phosphate buffer system |
| plays a role in buffering the CO2 as it is transported to the lungs for excretion. | Hemoglobin |
| play important roles in extracellular fluid pH homeostasis | lungs and kidneys |
| • expresses acid–base relationships in a mathematical formula | • expresses acid–base relationships in a mathematical formula |
| In the equation, A is the | proton acceptor (HCO3 |
| In the equation, Ha is the | proton donor, or weak acid (H2CO3) |
| In the equation, ph is the | Ph at which there is an equal concentration of protonated and unprotonated species |
| the end product of most aerobic metabolic processes, easily diffuses out of the tissue where it is produced and into the plasma and red cells in the surrounding capillaries | • Carbon dioxide |
| diffuses from the alveoli into the blood and is bound to hemoglobin | • Oxyhemoglobin (O2Hb) |
| • CO2 is eliminated through | ventilation |
| provide the first line of defense to change the acid–base status. | • The lungs together with the buffer systems |
| regulate the excretion of both acid and base, making them an important player in the regulation of acid–base balance | Kidney |
| • During alkalosis, the kidney excretes | HCO3– to compensate for the elevated blood pH. |
| • Clinicians order pH and blood gases together, along with electrolytes | (Na+, K+, and Cl–) to assess the acid–base status of a patient |
| • Under normal conditions, the body produces a net excess (blank) of acid (H+) each day that must be excreted by the kidney. | 50 to 100 mmol/L) |
| • The minimum urine pH that can be generated is | 4.6 |
| is produced by the deamination of glutamine and other amino acids | Ammonia |
| • During acidosis ammonia production is | increased |
| • The dissolved CO2 (dCO2) is in equilibrium with CO2 gas, which can be expelled by the | lungs |
| • participate rapidly in the regulation of blood pH through hypoventilation or hyperventilation. | lungs |
| • the non-respiratory or also known as the metabolic component, control the bicarbonate concentration | Kidneys |
| equilibrium between H2CO3 and CO2 in plasma | 1:800 |
| proportional to the PCO2 | • cH2CO3- |
| value for the combination of the solubility constant for PCO2 and the factor to convert mmHg to mmol/L | • 0.0307 mmol/L – mm Hg |
| • pH and PCO2 are measured in the | blood gas |
| • When the kidneys and lungs are functioning properly, the ratio of HCO3– to H2CO3 is | 20:1 to a ph of 7.40 |
| • A fall in HCO3- or a rise in PCO2 will cause | fall in ph |
| • A rise in HCO3- or a rise in PCO2 will cause | rise in PH |
| Ph | 7.35 – 7.45 |
| PCO2 (mm Hg) | 35 – 45 |
| HCO3- (mmol/L) | 22 – 29 |
| Total CO2 content (mmol/L) | 23 – 27 |
| PO2 (mmol/L) | 85 – 105 |
| SO2 (%) | >95 |
| - blood pH is less than the reference range (7.35 to 7.45)
- reflects excess acid or H+ concentration | Acidemia |
| - pH greater than the reference range (7.35 – 7.45)
- Reflects excess base | Alkalemia |
| - Caused by ventilatory dysfunction (a change in PCO2) | Primary respiratory acidosis or alkalosis |
| - Resulting from a change in the HCO3 ion level | Metabolic (Non-respiratory) Disorder |
| - response to maintain acid–base homeostasis
- The body tries to restore Acid-base homeostasis whenever an imbalance occurs | Compensation |
| - If the imbalance is of metabolic (non-respiratory) origin, the body compensates by | altering ventilation |
| - For disturbances of the respiratory component, the kidneys will compensate by | selectively excreting or reabsorbing specific ions |
| - The lungs can immediately compensate | by retaining or expelling carbon dioxide; however, this response is short term and often incomplete |
| are slower to respond (2 to 4 days), but the response is long term and sustained | Kidneys |
| - implies that the pH has returned to the normal range (the ratio of HCO3 – to H2CO3 of 20:1 has been restored) | Fully Compensated |
| - implies that the pH is approaching normal | Partially compensated |
| The body compensates for metabolic acidosis through | hyperventilation |
| decrease in alveolar ventilation, decreased elimination of CO2 by the lungs | - Primary respiratory acidosis- |
| Compensation for primary respiratory acidosis | metabolic processes |
| from a gain in HCO3–, causing an increase in the Ph | - Primary metabolic alkalosis |
| from an increased rate of alveolar ventilation causes excessive elimination of CO2 by the lungs | - Primary respiratory alkalosis |
