Acid Base Imbalances guide for nursing students.pptx

acid base imbalances guide for nursing students

1. Timby’s Introductory Medical–Surgical Nursing, 13e Chapter 16: Caring for Clients With Fluid, Electrolyte, and Acid–Base Imbalances

2. Fluid and Electrolyte Balance #1 Body fluids Components Water and chemicals Electrolytes Acids Bases

3. Fluid and Electrolyte Balance #1 Body fluids Components Water and chemicals Water is the primary component and the universal solvent of the body. Chemicals: Dissolved within this water are numerous chemical substances, which can be broadly categorized as electrolytes and non-electrolytes (like glucose and urea). The electrolytes are particularly important for their electrical and fluid-balancing properties.

4. Fluid and Electrolyte Balance #1 Body fluids Components Electrolytes Electrolytes are substances that carry an electrical charge when dissolved in fluid.

5. Fluid and Electrolyte Balance #1 Body fluids Components Acids These are substances that release hydrogen ions (H⁺) into a fluid. An increase in H⁺ concentration makes the fluid more acidic and lowers its pH. Bases These are substances that bind with or accept hydrogen ions. By removing free H⁺ from the solution, bases make the fluid more alkaline (or basic) and raise its pH.

6. Fluid and Electrolyte Balance #1 Body fluids Purpose regulate fluid volume buffer blood to keep its pH neutral

7. Fluid and Electrolyte Balance #2 Body fluid compartments 60% of body is water Intracellular fluid : fluid located within cells Extracellular fluid : fluid outside of the cells

8. Fluid and Electrolyte Balance #2 Body fluid compartments Intracellular fluid: fluid located within cells The ICF has a unique chemical makeup that is very different from the fluid outside the cells. It is rich in: Potassium (K⁺) Magnesium (Mg²⁺) Phosphate (PO₄³⁻) Proteins

9. Fluid and Electrolyte Balance #2 Body fluid compartments Extracellular fluid The ECF is characterized by a high concentration of: Sodium (Na⁺) Chloride (Cl⁻) Bicarbonate (HCO₃⁻) Sub-compartments: The ECF is further divided into two major sub-compartments: interstitial fluid and intravascular fluid.

10. Fluid and Electrolyte Balance #2 T he Dynamic Relationship Between Compartments The membranes separating these compartments (the cell membrane between ICF and ECF, and the capillary wall between interstitial and intravascular fluid) are semipermeable. This means that water can move freely between all compartments, driven by osmotic and hydrostatic pressures. However, the movement of electrolytes and proteins is more tightly regulated.

11. Intake and Output Average fluid intake Adult: 2500 mL/day (Range: 1800 to 3600 mL/day) Sources: liquids food metabolic water

12. Intake and Output Fluid elimination Sources Urination, bowel elimination, perspiration, breathing Insensible losses: sweat, exhaled air

13. Intake and Output Fluid elimination- The importance of balance The body's ability to precisely match fluid intake with fluid output is essential for maintaining: Normal Blood Volume and Blood Pressure Stable Electrolyte Concentrations Cellular Function

14. Distribution of Fluids and Electrolytes Physiologic process: translocation of fluid and exchange of chemicals (electrolytes, acids, bases) is continuous Five processes Osmosis : movement of water through a semipermeable membrane; tonicity Filtration : promotes movement of fluid according to pressure differences; kidneys Passive and facilitated diffusion; example: insulin facilitates distribution of glucose inside cells Active transport: sodium–potassium pump; requires ATP

15. Distribution of Fluids and Electrolytes Physiologic process: translocation of fluid and exchange of chemicals (electrolytes, acids, bases) is continuous Five processes Osmosis the passive movement of water through a semipermeable membrane from an area of lower solute concentration to an area of higher solute concentration. In simple terms, "water follows salt." The goal of osmosis is to equalize the concentration of solutes on both sides of the membrane. Tonicity: This term describes the effect a solution has on cell volume.

16. Distribution of Fluids and Electrolytes Physiologic process: translocation of fluid and exchange of chemicals (electrolytes, acids, bases) is continuous Five processes Osmosis Tonicity: This term describes the effect a solution has on cell volume. Isotonic Solution: Has the same solute concentration as the cell. There is no net movement of water, and the cell maintains its normal size (e.g., 0.9% Normal Saline). Hypotonic Solution: Has a lower solute concentration than the cell. Water moves into the cell, causing it to swell and potentially burst (hemolysis). Hypertonic Solution: Has a higher solute concentration than the cell. Water moves out of the cell, causing it to shrink (crenation).

17. Distribution of Fluids and Electrolytes Physiologic process: translocation of fluid and exchange of chemicals (electrolytes, acids, bases) is continuous Five processes Filtration Filtration promotes the movement of fluid and small solutes through a membrane according to pressure differences. It is a passive process driven by hydrostatic pressure, which is the pressure exerted by a fluid within a closed system (e.g., blood pressure). The kidneys are a prime example of filtration.

18. Distribution of Fluids and Electrolytes Physiologic process: translocation of fluid and exchange of chemicals (electrolytes, acids, bases) is continuous Passive and facilitated diffusion Diffusion is the passive movement of solutes from an area of higher concentration to an area of lower concentration, moving "down" their concentration gradient until equilibrium is reached. When we talk about passive diffusion and facilitated diffusion, we are talking about specific types of diffusion that happen across a biological cell membrane. Both are forms of passive transport, The only difference between them is that passive diffusion doesn't need help, while facilitated diffusion requires the help of a membrane protein. Passive Diffusion is the unassisted movement of small, nonpolar (hydrophobic) molecules directly through the lipid bilayer of the cell membrane. Facilitated Diffusion is the movement of molecules across the cell membrane that is "helped" or "facilitated" by membrane proteins. These molecules are either too large, too polar (hydrophilic), or have an electrical charge (ions), so they cannot pass directly through the lipid bilayer.

19. Distribution of Fluids and Electrolytes Physiologic process: translocation of fluid and exchange of chemicals (electrolytes, acids, bases) is continuous Five processes Active transport: Active transport is the movement of solutes against their concentration gradient (from an area of low concentration to an area of high concentration). Because this is an "uphill" movement, it requires energy, which is supplied by ATP (adenosine triphosphate).

20. Mechanisms of Fluid and Electrolyte Regulation Mechanisms to maintain normal fluid volume and electrolyte concentrations Types Osmoreceptors: neurons that sense blood concentration; simulate release of ADH; baroreceptors Renin–angiotensin–aldosterone system: chemicals released to increase BP and blood volume Natriuretic peptides: ANP and BNP released; increase urine production

21. Mechanisms of Fluid and Electrolyte Regulation Mechanisms to maintain normal fluid volume and electrolyte concentrations Types Osmoreceptors: This system is the primary regulator of water balance and blood concentration (osmolality). Osmoreceptors are specialized neurons located in the hypothalamus of the brain that sense the concentration of the blood. They are highly sensitive to changes in the amount of solutes (like sodium) relative to the amount of water in the blood. the Antidiuretic Hormone (ADH) System : ADH (also known as vasopressin) is released from the posterior pituitary gland into the bloodstream. It travels to the kidneys and acts on the collecting ducts, making them more permeable to water. While osmoreceptors respond to concentration, baroreceptors respond to volume/pressure. If blood pressure drops significantly (e.g., due to hemorrhage), baroreceptors will also stimulate the release of ADH.

22. Mechanisms of Fluid and Electrolyte Regulation Mechanisms to maintain normal fluid volume and electrolyte concentrations Types Renin–angiotensin–aldosterone system: This is a powerful hormonal cascade that is the primary regulator of long-term blood pressure and sodium balance.

23. Mechanisms of Fluid and Electrolyte Regulation Mechanisms to maintain normal fluid volume and electrolyte concentrations Types Natriuretic peptides This system is the hormonal counterbalance to the RAAS. While the RAAS works to raise blood pressure and volume, the natriuretic peptides work to lower them.

24. Fluid Imbalances #1: Hypovolemia and Dehydration Hypovolemia and Dehydration Definitions and Pathophysiology Hypovolemia: Definition: Hypovolemia specifically refers to a low volume of extracellular fluid, particularly the fluid in the intravascular space (blood plasma). It is a state of volume depletion. Dehydration: Definition: Dehydration is a broader term that occurs when extracellular and intracellular fluids are reduced. It happens when the loss of water is greater than the loss of electrolytes, particularly sodium. Causes Vomiting, Diarrhea, Wounds, Profuse Urination: Vomiting and Diarrhea Wounds Profuse Urination (Polyuria) Other Causes: Hemorrhage (blood loss), profuse sweating, and inadequate fluid intake. Hemoconcentration: This is a key consequence of fluid volume loss

25. Fluid Imbalances #1: Hypovolemia and Dehydration Assessment Findings Thirst Other Key Signs and Symptoms: Cardiovascular: Tachycardia (rapid heart rate) and hypotension (low blood pressure) Integumentary: Poor skin turgor (skin "tents" when pinched), dry mucous membranes. Renal: Decreased urine output (oliguria) as the kidneys try to conserve water. Neurological: Weakness, dizziness, confusion, or lethargy Diagnostic Findings Laboratory tests will reflect the state of hemoconcentration and the kidneys' response. Elevated Hematocrit (Hct) and Blood Cell Counts Elevated Urine Specific Gravity Elevated Blood Urea Nitrogen (BUN)

26. Fluid Imbalances #1: Hypovolemia and Dehydration The primary goal is to restore the fluid deficit and correct any electrolyte imbalances. Oral Rehydration: For mild to moderate dehydration, replacing fluids by mouth is the preferred method. This can be done with water, but solutions containing electrolytes and some sugar (oral rehydration solutions) are often more effective, especially after diarrhea or vomiting. IV Fluid Administration: For severe hypovolemia or when the patient cannot take fluids orally, intravenous fluid replacement is necessary. The choice of fluid (e.g., isotonic, hypotonic) depends on the patient's specific electrolyte and volume status.

27. Fluid Imbalances #1: Hypovolemia and Dehydration The nurse's role is crucial in monitoring, managing fluid replacement, and providing patient education. Monitoring: The nurse must closely monitor the patient's vital signs, intake and output, daily weight (the most accurate indicator of fluid status), and mental status. Fluid Management: Administer IV fluids as prescribed and encourage oral intake if appropriate. Patient Education: 8 to 10 Glasses of Water/Day Avoid Caffeinated Beverages Restrict Sodium

28. Fluid Imbalances #2 Hypervolemia: high volume of water in intravascular fluid compartment Causes Hypervolemia results from either excessive intake of fluid and sodium or impaired mechanisms for their excretion. Excessive Oral Intake or IV Fluids: Heart Failure: Kidney Disease: Adrenal Gland Dysfunction: Circulatory Overload:

29. Fluid Imbalances #2 Hypervolemia: high volume of water in intravascular fluid compartment Assessment Findings The signs and symptoms of hypervolemia are a direct result of the expanded fluid volume in the vascular and interstitial spaces. Weight Gain Elevated Blood Pressure (Hypertension) Pitting or Nonpitting Edema; Dependent Edema: Moist Lung Sounds (Crackles) Diagnostic Findings Laboratory results will reflect a state of hemodilution, where the cellular components of the blood are diluted by the excess plasma fluid. Low Hematocrit (Hct) and Blood Cell Count Low Urine Specific Gravity

30. Fluid Imbalances #2 Hypervolemia: high volume of water in intravascular fluid compartment Medical Management The goal of treatment is to remove the excess fluid and sodium from the body. Restrict Oral or Parenteral Fluid: The patient will be placed on a fluid restriction, where their total daily fluid intake (both oral and IV) is limited to a specific amount. Diuretics: These are medications ("water pills") that act on the kidneys to increase the excretion of sodium and water. Loop diuretics like furosemide (Lasix) are very powerful and are often used for severe fluid overload. Limit Sodium: A low-sodium diet is prescribed. Since "water follows salt," restricting sodium intake helps to prevent further fluid retention.

31. Nursing Care Plan: Hypervolemia Nursing diagnosis: Excess Fluid Volume related to intake that exceeds fluid loss Baseline and daily weights (weight gain 2 lb/24 hours) Accurate intake and output Auscultate lung sounds Measure BP, heart rate, respiratory rate Inspect skin for edema, cracks, and breakdown See Box 16-1, Nursing Care Plan 16-1, and Nursing Guidelines 16-1

32. Question #1 A client is at risk for impaired skin integrity due to compromised circulation related to heart failure. Interventions to maintain intact skin includes: A) Changing the client’s position every 4 hours B) Restricting ambulation C) Applying elastic stockings D) Keeping client’s legs lower than the heart

33. Answer to Question #1 C) Applying elastic stockings Rationale: Elastic stockings support valves in the veins and prevent fluid from pooling in dependent areas such as the feet and ankles.

34. Third-Spacing Definition: Third-spacing is the translocation of fluid from the intravascular space (the blood vessels) to the interstitial tissue compartments, where it becomes trapped and is no longer available to support normal physiological functions like blood pressure. It is not a loss of fluid from the body, but a severe maldistribution of fluid within the body. This trapped fluid is sometimes referred to as "third-space" fluid. Pathophysiology: The movement of fluid between the intravascular and interstitial spaces is governed by a balance between two opposing forces: Hydrostatic Pressure Oncotic Pressure (or Colloid Osmotic Pressure) Third-spacing occurs when this balance is disrupted. Specifically, it happens when there is a significant decrease in oncotic pressure (not enough protein to hold fluid in) or a significant increase in capillary permeability (the capillary walls become leaky), allowing both fluid and protein to escape into the interstitial space. The result is a depletion of the intravascular volume, even though the patient's total body water may be normal or even high.

35. Third-Spacing Third-spacing—translocation of fluid from intravascular to tissue compartments Causes: Hypoalbuminemia Burns Severe Allergic Reactions (Anaphylaxis) Other Causes: Sepsis, pancreatitis, and major abdominal surgery can also trigger a systemic inflammatory response that leads to third-spacing.

36. Third-Spacing Assessment Findings The assessment findings are paradoxical. The patient shows signs of both fluid overload (in the tissues) and fluid volume deficit (in the blood vessels). Ascites, Generalized Edema: Generalized Edema (Anasarca) Ascites The patient will also have a rapid increase in body weight due to this trapped fluid. Signs of Intravascular Depletion: At the same time, the patient will exhibit classic signs of hypovolemia, including: Tachycardia (rapid heart rate) Hypotension (low blood pressure) Decreased urine output (oliguria) Diagnostic Findings The laboratory and hemodynamic findings reflect the paradoxical state of intravascular dehydration and total body fluid overload. Hemoconcentration Central Venous Pressure (CVP) Normal or Low Blood Counts Borderline

37. Third-Spacing Third-spacing—translocation of fluid from intravascular to tissue compartments Medical Management The goal of treatment is to pull the trapped interstitial fluid back into the intravascular space and then help the body excrete the excess. Albumin Infusion: This is a key intervention. Administering IV albumin directly increases the oncotic pressure within the blood vessels. This increased "pulling" force helps to draw the third-spaced fluid from the interstitial tissues back into the capillaries. IV Diuretic: A diuretic (like furosemide) is often given after or concurrently with the albumin infusion. The albumin pulls the fluid back into the circulation, and the diuretic then helps the kidneys to excrete that excess fluid from the body as urine. Giving a diuretic alone without first restoring the intravascular volume would be dangerous and would worsen the hypovolemia.

38. Third-Spacing The nurse's role is critical in monitoring the delicate fluid balance during treatment. Intensive Monitoring Administering Infusions Assessment Supportive Care

39. Electrolyte Imbalances Electrolyte imbalances occur as deficits and/or excess; accompanied by fluid changes Electrolytes are minerals in the body that carry an electric charge. They are essential for nerve function, muscle contraction, hydration, and maintaining the body's acid-base balance. An electrolyte imbalance occurs when the concentration of a specific electrolyte in the blood is either too high or too low.

40. Electrolyte Imbalances Electrolyte imbalances occur as deficits and/or excess; accompanied by fluid changes Causes of De ficits Administration of IV Fluids Vomiting, Diarrhea: These are major causes of electrolyte loss. Vomiting leads to a significant loss of potassium, chloride, and hydrogen ions (acid). Diarrhea leads to a significant loss of potassium and bicarbonate (base). Diuretics: These medications ("water pills") are designed to make the kidneys excrete more sodium and water. Many diuretics, particularly loop and thiazide diuretics, also cause a significant loss of potassium and magnesium, leading to deficits of these critical electrolytes. Other Causes: Profuse sweating, kidney disease, and certain hormonal imbalances can also lead to electrolyte deficits.

41. Electrolyte Imbalances Electrolyte imbalances occur as deficits and/or excess; accompanied by fluid changes Causes of Excess Orally Consumed or Parenteral Administration of Electrolytes: Kidney Failure: This is a primary cause of electrolyte excess. Healthy kidneys are responsible for filtering and excreting excess electrolytes. In kidney failure, this ability is lost, and electrolytes like potassium, magnesium, and phosphate can build up to dangerously high levels in the blood. Endocrine Dysfunction: Hormonal imbalances can cause electrolyte excess. For example, adrenal insufficiency (Addison's disease) leads to a deficiency of aldosterone, which causes the body to retain potassium, leading to hyperkalemia. Crushing Injuries, Burns: These types of massive tissue trauma cause a large-scale destruction of cells. Since cells are rich in potassium, this cellular breakdown releases huge amounts of potassium into the bloodstream, a condition known as rhabdomyolysis, which can cause life-threatening hyperkalemia.

42. Electrolyte Imbalances Priority electrolyte imbalances sodium potassium calcium magnesium

43. Sodium Imbalances #1 Sodium (Na⁺) Sodium is the most abundant electrolyte in the extracellular fluid (ECF) and is the primary determinant of ECF volume and concentration. Its balance is critical for the normal functioning of the entire body. Functions of Sodium Maintaining Normal Nerve and Muscle Activity Regulating Osmotic Pressure Preserving Acid–Base Balance

44. Sodium Imbalances #1 Hyponatremia—serum level below 135 mEq/L Causes: profuse diaphoresis, diuresis, loss of GI secretions (suctioning, drains), Addison disease Assessment Findings: mental confusion, muscular weakness, anorexia, elevated body temperature, tachycardia Medical Management: foods high in sodium, IV sodium chloride

45. Sodium Imbalances #1 Nursing Management Monitoring Safety Fluid and Diet Management Patient Education

46. Sodium Imbalances #2 Hypernatremia Causes: diarrhea, excessive salt intake, high fever, excessive water loss, decreased water intake Assessment Findings: thirst; dry, sticky mucous membranes; decreased urine output; fever Diagnostic Finding: >145 mEq/L Medical Management: water intake, hypotonic IV solution (0.45% NaCl or 5% Dextrose)

47. Sodium Imbalances #2 Nursing Management The nurse's role is critical in monitoring the patient's response to treatment and ensuring safety. Monitoring Intake and Output (I&O) Assess Vital Signs Fluid Administration Dietary Management Patient Education

48. Potassium Imbalances #1 Potassium (K⁺) Potassium is the most abundant electrolyte in the intracellular fluid (ICF). Its concentration inside the cells is very high, while its concentration in the blood is kept within a very narrow range. This steep concentration gradient is essential for life. Function of Potassium Maintaining Normal Nerve and Muscle Activity Nerve Impulse Conduction: Transmitting signals along nerves. Skeletal Muscle Contraction: Allowing muscles to contract and relax properly. Cardiac Muscle Contraction: This is its most critical function. The precise balance of potassium is essential for maintaining the normal rhythm and contractility of the heart.

49. Potassium Imbalances #1 Hypokalemia Causes: potassium-wasting diuretics (Lasix, HydroDIURIL), GI tract fluid loss (suctioning, drains, vomiting), corticosteroids, IV insulin and glucose Assessment Findings: fatigue, weakness, nausea, cardiac dysrhythmias, paresthesias Diagnostic Finding: <3.0 mEq/L symptoms occur Medical Management: potassium-sparing diuretics (Aldactone), K + foods, oral supplements (K-Lor), IV

50. Potassium Imbalances #1 Nursing Management Monitoring Safety Dietary and Supplement Management Patient Education

51. Potassium Imbalances #2 Hyperkalemia Causes: renal failure, potassium-sparing diuretics, supplements, diet sodas, crushing injuries, Addison disease, parenteral potassium salts Assessment Findings: diarrhea, nausea, muscle weakness, cardiac dysrhythmias Diagnostic Finding: >5.5 mEq/L Medical management: decreasing K + intake, administration of insulin and glucose, Kayexalate, peritoneal dialysis or hemodialysis

52. Potassium Imbalances #2 Nursing Management The nurse's role is critical in monitoring for and managing this life-threatening condition. Monitoring Medications Diet Teaching Safety Preparing for Dialysis

53. Calcium Imbalances #1 Calcium (Ca²⁺) Calcium is the most abundant mineral in the body, with 99% of it stored in the bones and teeth. The remaining 1% circulates in the blood and is absolutely critical for numerous life-sustaining physiological processes. Function of Calcium Blood Clotting Transmission of Nerve Impulses Muscle Contraction Regulated by the Parathyroid Gland: The level of calcium in the blood is tightly regulated by the parathyroid gland. When blood calcium levels drop, the parathyroid glands release Parathyroid Hormone (PTH). PTH raises blood calcium by: Stimulating the release of calcium from the bones. Increasing calcium reabsorption by the kidneys. Increasing the activation of Vitamin D, which in turn enhances the absorption of calcium from the intestines.

54. Calcium Imbalances #1 Hypocalcemia Function: blood clotting, transmission of nerve impulses, regulated by parathyroid gland Causes: vitamin D deficiency, hypoparathyroidism, burns, pancreatitis, corticosteroids, blood administration, intestinal malabsorption Assessment Findings: tingling, circumoral paresthesia, muscle cramps, positive Chvostek sign, Trousseau sign, bleeding, tetany Diagnostic Finding: serum calcium <8.8 mg/dL Medical Management: oral calcium and vitamin D, IV calcium

55. Calcium Imbalances #1 Nursing Management Monitoring Safety Medication Administration Patient Education

56. Calcium Imbalances #2 Hypercalcemia Causes: parathyroid tumors, multiple fractures, Paget disease, prolonged immobilization, chemotherapy agents, multiple myeloma Assessment Findings: deep bone pain, constipation, anorexia, polyuria, pathologic fractures, kidney stones Diagnostic Finding: serum calcium >10 mg/dL Medical Management: cause, IV sodium chloride, Lasix, corticosteroids or plicamycin

57. Calcium Imbalances #2 Nursing Management The nurse's role is focused on promoting safety, managing hydration, and patient education. Diet Teaching Promote Fluids Fall Safety Monitoring

58. Magnesium Imbalances #1 Magnesium (Mg²⁺) Magnesium is a crucial electrolyte, with the majority of it stored in the bones and inside the cells. It acts as a co-factor or "helper molecule" in hundreds of essential biochemical reactions in the body. Function of Magnesium Transmission of Nerve Impulses Activation of Enzyme Systems, Including Functioning of B Vitamins: This is its most widespread role. Magnesium is a critical co-factor for more than 300 enzyme systems. It is essential for: Energy Production Protein Synthesis B Vitamin Function Maintaining Heart Rhythm

59. Magnesium Imbalances #1 Hypomagnesemia Causes: alcoholism, diabetic ketoacidosis, renal disease, burns, malnutrition, intestinal malabsorption, diuresis, prolonged gastric suction Assessment Findings: tachycardia, paresthesias, neuromuscular irritability, HTN, mental changes Diagnostic Finding: serum magnesium <1.3 mEq/L Medical Management: oral or IV magnesium, diet supplements

60. Magnesium Imbalances #1 Nursing Management Monitoring Safety Medication Administration Patient Education

61. Magnesium Imbalances #2 Hypermagnesemia Causes: renal failure, Addison disease, excessive antacid or laxative use, hyperparathyroidism Assessment Findings: flushing, hypotension, lethargy, bradycardia, muscle weakness, coma Diagnostic Finding: serum magnesium >2.1 mEq/L Medical Management: decreasing oral magnesium or parenteral replacement, mechanical ventilation Nursing Management: BP and respiratory monitoring

62. Magnesium Imbalances #2 Nursing Management The nurse's role is focused on vigilant monitoring, safety, and patient education. BP and Respiratory Monitoring Neurological and Muscular Assessment Safety Patient Education

63. Question #2 Which of the following interventions would be appropriate when caring for a client with hypercalcemia? A) Encourage fluids. B) Promote bed rest. C) Administer calcium supplement tablets. D) Administer antibiotics.

64. Answer to Question #2 A) Encourage fluids. Rationale: Hypercalcemia is a condition in which serum calcium is elevated. By providing increased amounts of fluid, calcium excretion is promoted and the amount of circulating calcium decreases.

65. Acid–Base Balance Acid-Base Balance Acid-base balance refers to the body's process of maintaining a stable pH in its fluids. This balance is one of the most tightly regulated aspects of human physiology because all cellular functions, especially enzyme activity, are highly sensitive to even minor changes in pH. Regulation of Normal Plasma pH Normal Plasma pH: The pH of the blood is kept within a very narrow, slightly alkaline range of 7.35 to 7.45. This is considered the normal, life-sustaining range. Limits of Viability: The body's tolerance for pH changes is extremely limited. Death occurs quickly if the plasma pH is outside the range of 6.8 to 7.8. A pH below 6.8 or above 7.8 is generally incompatible with life because it causes a catastrophic breakdown of all metabolic processes.

66. Acid–Base Balance The Bicarbonate Buffer System Carbonic Acid (H₂CO₃) and Bicarbonate (HCO₃⁻): The body's primary mechanism for maintaining a stable pH is the carbonic acid-bicarbonate buffer system. This system involves a delicate balance between a weak acid (carbonic acid) and its corresponding base (bicarbonate). Carbonic Acid (H₂CO₃): This is the "acid" side of the equation. It is formed when carbon dioxide (CO₂), a waste product of metabolism, dissolves in the blood. Bicarbonate (HCO₃⁻): This is the "base" or "alkaline" side of the equation. It is a substance that can accept a hydrogen ion.

67. Acid–Base Balance The Bicarbonate Buffer System Chemical Buffering: This system acts as a chemical "sponge" for hydrogen ions (H⁺). Adding Hydrogen Ions: If the blood becomes too acidic (too much H⁺), the bicarbonate (HCO₃⁻) in the blood will bind with the excess H⁺ to form carbonic acid (H₂CO₃). This effectively "soaks up" the free acid, preventing a drastic drop in pH. Removing Hydrogen Ions: If the blood becomes too alkaline (too little H⁺), the carbonic acid (H₂CO₃) will dissociate, releasing H⁺ back into the blood to prevent a drastic rise in pH. This chemical buffering happens instantly and is the body's first line of defense against pH changes.

68. Acid–Base Balance Organ Regulation: Lungs and Kidneys While chemical buffers provide an immediate response, the long-term control of acid-base balance is managed by the lungs and the kidneys. Lungs Regulate Carbonic Acid Levels: The lungs control the "acid" side of the equation by regulating the amount of carbon dioxide (CO₂) in the blood. Mechanism: If the blood becomes too acidic, the brain triggers an increase in the rate and depth of breathing (hyperventilation). This "blows off" more CO₂, which reduces the amount of carbonic acid in the blood, thereby raising the pH back toward normal. If the blood becomes too alkaline, breathing slows down (hypoventilation). This retains CO₂, increasing the amount of carbonic acid and lowering the pH back toward normal. This respiratory compensation is rapid, occurring within minutes to hours.

69. Acid–Base Balance Organ Regulation: Lungs and Kidneys While chemical buffers provide an immediate response, the long-term control of acid-base balance is managed by the lungs and the kidneys. Kidneys Regulate Bicarbonate Levels: The kidneys control the "base" side of the equation by regulating the amount of bicarbonate (HCO₃⁻) in the blood. Mechanism: The kidneys have the ability to either excrete bicarbonate into the urine (if the blood is too alkaline) or reabsorb and generate new bicarbonate (if the blood is too acidic). They can also directly excrete hydrogen ions. This metabolic/renal compensation is very powerful but much slower than the respiratory response, taking hours to days to have a significant effect.

70. Acid–Base Balance Organ Regulation: Lungs and Kidneys While chemical buffers provide an immediate response, the long-term control of acid-base balance is managed by the lungs and the kidneys. Decompensation: When both the buffer systems and the compensatory actions of the lungs and kidneys fail to keep the pH within the normal range, the body is in a state of decompensation. This is when the pH becomes dangerously acidic or alkaline, leading to severe clinical consequences.

71. Acid–Base Balance Types of Imbalances Acid-base imbalances are categorized based on the primary problem (respiratory or metabolic) and the resulting pH change (acidosis or alkalosis). Acidosis: This is a state where the blood pH is below 7.35. It is caused by either an accumulation of acid or a loss of base. Respiratory Acidosis: Caused by the retention of CO₂ due to inadequate breathing (e.g., from COPD, pneumonia, or drug overdose). This leads to an excessive accumulation of carbonic acid. Metabolic Acidosis: Caused by either the accumulation of other metabolic acids (e.g., ketones in DKA, lactic acid in shock) or an excessive loss of bicarbonate from the body (e.g., from severe diarrhea).

72. Acid–Base Balance Types of Imbalances Acid-base imbalances are categorized based on the primary problem (respiratory or metabolic) and the resulting pH change (acidosis or alkalosis). Alkalosis: This is a state where the blood pH is above 7.45. It is caused by either an accumulation of base or a loss of acid. Respiratory Alkalosis: Caused by blowing off too much CO₂ due to hyperventilation (e.g., from anxiety, pain, or fever). This leads to a deficit of carbonic acid. Metabolic Alkalosis: Caused by either an excessive accumulation of bases (e.g., from ingesting too much bicarbonate/antacids) or a loss of acid from the body (e.g., from prolonged vomiting or gastric suction).

73. Acid–Base Imbalances #1 Metabolic Acidosis (pH <7.35 to 7.45) See Table 16-3 Metabolic acidosis is a primary acid-base imbalance characterized by a low blood pH (less than 7.35) and a low plasma bicarbonate (HCO₃⁻) level. It occurs when the body either produces too much acid or loses too much base.

74. Acid–Base Imbalances #1 Metabolic Acidosis (pH <7.35 to 7.45) See Table 16-3 Causes The causes of metabolic acidosis can be broadly divided into those that add acid to the body and those that cause a loss of bicarbonate. (See Table 16-3, which would provide a comprehensive list of these causes). Increased Acid Production: Impaired Acid Excretion: Loss of Bicarbonate:

75. Acid–Base Imbalances #1 Metabolic Acidosis (pH <7.35 to 7.45) See Table 16-3 The signs and symptoms are a result of the body's attempt to compensate for the acidosis and the effect of the low pH on organ function. Deep and Rapid Breathing (Kussmaul's Breathing): This is the hallmark respiratory compensation. The brain's respiratory center detects the high level of acid in the blood and triggers a characteristic pattern of breathing that is very deep and rapid. This is called Kussmaul's breathing. The purpose is to "blow off" as much carbon dioxide (an acid) as possible to try and raise the blood pH back toward normal. Nausea, Vomiting, Abdominal Pain: These gastrointestinal symptoms are common, especially in DKA. Headache, Flushing, Weakness: The low pH can cause vasodilation, leading to a headache and warm, flushed skin. The effect on the central nervous system and muscles can cause lethargy, confusion, and generalized weakness. Anion Gap: normal or high

76. Acid–Base Imbalances #1 Metabolic Acidosis (pH <7.35 to 7.45) See Table 16-3 Medical Management The primary goal is to treat the underlying cause of the acidosis. Treat the Cause Replacing Fluids and Electrolytes IV Bicarbonate Nursing Management The nurse's role is critical in monitoring the patient, ensuring safety, and administering treatments. Monitoring Safety Administering Treatments Interpreting Lab Values

77. Acid–Base Imbalances #2 Metabolic Alkalosis (pH >7.45) Metabolic alkalosis is a primary acid-base imbalance characterized by a high blood pH (greater than 7.45) and a high plasma bicarbonate (HCO₃⁻) level. It occurs when the body either gains too much base or loses too much acid.

78. Acid–Base Imbalances #2 Metabolic Alkalosis (pH >7.45) Causes Excessive Bicarbonate-Containing Drugs Diuretic Therapy Vomiting and Gastric Suctioning

79. Acid–Base Imbalances #2 Metabolic Alkalosis (pH >7.45) Assessment Findings The signs and symptoms of metabolic alkalosis are related to the increased pH and the associated electrolyte imbalances (especially hypokalemia and hypocalcemia). Anorexia, Nausea Paresthesias, Confusion Hypertonic Reflexes, Tetany Decreased Respirations (Hypoventilation)

80. Acid–Base Imbalances #2 Medical Management The primary goal is to treat the underlying cause of the alkalosis. Treat the Cause Potassium Administration Sodium Chloride Administration Nursing Management The nurse's role is focused on monitoring, safety, and reporting critical findings. (See Table 16-3 for a summary of acid-base disorders). Monitoring and Interpreting ABG Findings Reports Assessment Findings Changes in the patient's respiratory status (e.g., shallow breathing, periods of apnea). Changes in neurological status (e.g., increasing confusion or lethargy). Signs of neuromuscular irritability (e.g., twitching, cramping, or a positive Chvostek's/Trousseau's sign). Cardiac monitoring for any arrhythmias, which can be caused by the associated electrolyte imbalances. Safety Administering Treatments

81. Acid–Base Imbalances #3 Respiratory Acidosis (pH <7.35) Respiratory acidosis is a primary acid-base imbalance characterized by a low blood pH (less than 7.35) and a high level of carbon dioxide in the blood (PaCO₂ > 45 mm Hg). It is always caused by inadequate ventilation, which leads to the retention of CO₂.

82. Acid–Base Imbalances #3 Respiratory Acidosis (pH <7.35) Any condition that impairs breathing or gas exchange can cause respiratory acidosis. Airway Obstruction: Impaired Gas Exchange: Depressed Respiratory Drive: Neuromuscular Impairment

83. Acid–Base Imbalances #3 Respiratory Acidosis (pH <7.35) The signs and symptoms are a result of the high CO₂ levels (hypercapnia) and the resulting low pH. Respiratory Insufficiency Shallow, slow respirations. Dyspnea (shortness of breath). Use of accessory muscles to breathe. Cyanosis Neurological Changes: Headache, confusion, and lethargy. Tremors or a characteristic "flapping" tremor of the hands called asterixis. In severe cases, it can progress to somnolence, coma, and death.

84. Acid–Base Imbalances #3 Medical Management The primary goal of treatment is to improve ventilation to clear the excess CO₂ from the body. Mechanical Ventilation Airway Suctioning Bronchodilators and Antibiotics: Oxygen Therapy

85. Acid–Base Imbalances #3 Nursing Management for Respiratory acidosis The nurse's primary goals are to improve ventilation, ensure safety, and monitor for changes. 1. Assessment and Monitoring Monitor Breathing: Frequently check respiratory rate, depth, and lung sounds (wheezing, crackles). Assess Neurological Status: Watch for confusion, lethargy, or tremors. A change in level of consciousness is a critical sign. Track Vitals & ABGs: Monitor O₂ saturation, heart rhythm, and report critical Arterial Blood Gas (ABG) results immediately. 2. Key Interventions Positioning: Place the patient in a semi-Fowler's or high-Fowler's position to maximize lung expansion. Maintain Airway Patency: Encourage coughing and deep breathing. Perform suctioning as needed to clear secretions. Administer Treatments: Provide prescribed bronchodilators, antibiotics, and oxygen. Prepare for Intervention: Anticipate the need for mechanical ventilation if the patient's condition worsens. 3. Safety and Support Prevent Falls: Implement safety precautions for confused or weak patients. Reduce Anxiety: Maintain a calm, reassuring presence to help ease the work of breathing. 4. Patient Education For chronic conditions (COPD, asthma), teach proper medication use, smoking cessation, and the early signs of an exacerbation to prevent future episodes.

86. Acid–Base Imbalances #4 Respiratory Alkalosis (pH 7.45) Respiratory alkalosis is a primary acid-base imbalance characterized by a high blood pH (greater than 7.45) and a low level of carbon dioxide in the blood (PaCO₂ < 35 mm Hg). It is always caused by hyperventilation—breathing that is too fast or too deep, which leads to an excessive "blowing off" of CO₂.

87. Acid–Base Imbalances #4 Respiratory Alkalosis (pH 7.45) Causes Anxiety Fever Overactive Thyroid (Hyperthyroidism) ASA (Aspirin) Poisoning Mechanical Ventilation

88. Acid–Base Imbalances #4 Respiratory Alkalosis (pH 7.45) Assessment Findings The signs and symptoms are a direct result of the low CO₂ levels (hypocapnia) and the effect of the high pH on the nervous system. Increased Respiratory Rate (Tachypnea) Light-headedness Numbness and Tingling of Fingers and Toes (Paresthesias) Sweating (Diaphoresis) and Panic

89. Acid–Base Imbalances #4 Respiratory Alkalosis (pH 7.45) Medical Management The goal of treatment is to increase the level of CO₂ in the blood by slowing the respiratory rate. Treat the Underlying Cause Rebreathe Expired Air (Brown Bag Breathing) Sedation

90. Acid–Base Imbalances #4 Respiratory Alkalosis (pH 7.45) Nursing Management The nurse's role is to provide immediate intervention to control breathing, monitor the patient's status, and offer reassurance. Immediate Intervention and Coaching Report Assessment Findings Reduce Anxiety Safety

91. Question #3 Which acid–base disturbance would be most characteristic of a narcotic overdose? A) Metabolic acidosis B) Respiratory acidosis C) Metabolic alkalosis D) Respiratory alkalosis

92. Answer to Question #3 B) Respiratory acidosis Rationale: A narcotic overdose slows the rate and depth of breathing. This leads to retention of carbon dioxide (acid). Hypoventilation problems produce respiratory acidosis.