Acid-Base Balance Final Notes PDF

Module 12: Acid–Base Balance Describe how the respiratory and renal systems help maintain homeostasis and regulate the body’s acid–base balance. Identify buffering mechanisms that occur to maintain acid–base balance. List common causes of acid–base imbalances. Analyze normal and abnormal blood gas l...

Module 12: Acid–Base Balance Describe how the respiratory and renal systems help maintain homeostasis and regulate the body’s acid–base balance. Identify buffering mechanisms that occur to maintain acid–base balance. List common causes of acid–base imbalances. Analyze normal and abnormal blood gas levels. Apply holistic nursing care based on the concept of acid–base balance to clients needing chronic care management. Why are older adults more susceptible to acidosis? May be on diuretics, ASA, antacids Decreased renal and respiratory function Chronic Health Conditions: Older adults are more likely to have chronic conditions like diabetes, chronic kidney disease, or respiratory disorders (e.g., COPD), which can contribute to acidosis. For example, diabetic ketoacidosis occurs in uncontrolled diabetes, and respiratory acidosis can occur in individuals with lung conditions that impair ventilation. Susceptible to infections Describe how the respiratory and renal systems help maintain homeostasis and regulate the body’s acid–base balance. The respiratory and renal systems influence this reaction by: ○ CO2 + H20 + H2C03+H+ + HCO3- Pulmonary Regulation ○ Central or arterial chemoreceptors detect the pH change in the body hence, lung ventilation may increase or decrease to flush out or retain CO2. ○ lungs maintain acid base balance through control of PCO, ○ pulmonary regulation is fast, occurs within minst or hours ★ Respiratory acidosis: any disorder that interferes with ventilation (PCO2 > 5.7 & pH < 7.35) ○ (↓ pH ↑ PCO,): In an acidic environment less oxygen can be carried by hemoglobin leading to a reduction of oxygen delivery to cells, hemoglobin gives up its 02 to tissues under conditions of increased H+ ion concentration. ○ This leads to an increase in the respiratory rate and depth of breathing ○ Metabolic compensation: ↓ HCO3 (< 22) ★ Respiratory alkalosis: ○ (↑ pH ↓ PCO,) Direct cause is always hyperventilation (e.g too much mechanical ventilation, pulmonary lesions) causing the body to respond in a decrease in ventilation and resp rate. In alkalosis states Hb/02 bond is strengthened (The Bohr effect). This will maintain 02 saturation, but not cellular oxygen delivery due to the decreased ability to release oxygen to tissues. ○ Metabolic compensation: ↑ HCO3- (> 26) Renal Regulation ○ Kidneys may increase or decrease retention of HCO3- or decrease and increase excretion of H+  ○ Usually slower, it takes days to respond to pH imbalance ○ Kidneys maintain acid base balance through the excretion or reabsorption of HCO3 (bicarbonate acid) ★ Metabolic acidosis: ○ (↓ рН ↓ НСО3-) In the kidneys H2CO3 dissociates to release free H+ and HCO3-, and stimulates the kidneys to retain HCO3- and sodium ions (Nat), and excrete H+. ○ The HCO3- retained is re-circulated and helps to buffer further free H+. ○ However, It takes around 3 days for a patient to have established a steady state of compensation. ○ The same processes that cause resp rate to increase in respiratory acidosis are present in metabolic acidosis, therefore, patients with a metabolic acidosis have a fast respiratory rate, ○ In acidosis, cells release K+ into blood in exchange for H+, this may lead to hyperkalemia and characteristic changes in the ECG ○ Pulmonary compensation: ↑ PaCO, (> 45) ★ Metabolic Alkalosis: ○ (↑ рН ↑ НСО3-) is the result of excess HCO3- or decreased H+ concentration, caused by an excessive loss of non-volatile or fixed acids, ○ Metabolic alkalosis excites central and peripheral nervous systems. Compensation is met by lungs, kidneys and by the release of H+ from cells. There will be a decreased resp rate increasing pco2, kidneys start to increase excretion of HCO3- and reduce the excretion of H+. ○ excess Na+ and Cl-) are excreted along with HCO3- → hyponatremia. ○ an alkaline environment leads to vasoconstriction with cerebral and peripheral hypoxia. ○ The body's cell will release H+ in response to the depletion, and exchange H+ for intaking K+ which can lead to confusion and arrhythmias. ○ Pulmonary compensation: ↓ PaCO, (< 35) Identify buffering mechanisms that occur to maintain acid–base balance. ★ 3 Main Buffers ○ Phosphate buffer system ○ this comprises dihydrogen phosphate (a weak acid) you get this from your diet can be excreted through urine being a weak acid, it can dissociate into hydrogen phosphate and hydrogen ions any ↑ in H+ concentration can be met with resistance through a change in the equilibrium towards the left this reduces Ht ion concentration by producing more hydrogen phosphate any ↓ in H+ concentration shifts the equilibrium to the right this i the amount of hydrogen phosphate in the blood thus restoring equilibrium and brings back pH to the optimal range  ○ Carbonic Acid Bicarbonate (CO2/HCO3-) buffer system CO2 + H2O H2CO3 H+ + HCO3- important in acid base balance H+ concentration of body fluids is influenced by both PCO, and HCO3 concentration there's a weak carbonic acid which can readily dissociate into bicarbonate and H+ carbonic acid is produced through respiration Any ↑ in pH through the fall of H+ concentration (↑ pH + ↓ H+ = ↓ PaCO,)is met with resistance through a change of equilibrium to the right this ↓ PaCO, dissolved in the blood this continues until the Ht concentration is restored to normal any ↓ in pH through the increase of Ht concentration ( ↓ pH & ↑ H+ = ↑ PaCO2) is met with resistance through a change of equilibrium to the left this ↑ the amount of Paco2 dissolved in the blood this continues until the H+ concentration is restored to normal ○ proteins (intra and extracellular) buffer system any physiological process that tries to ↑ the pH (for example, the release of hydroxyl ions) can be resisted by the liberation of protons from the amino groups and the ammonium ions by product of this process is the production of water any physiological process that tries to ↓ the pH (for example the release of H+) is met with resistance through the binding of H+ to free hydroxyl groups and amino groups of proteins this resists the fall in pH and maintains the pH of blood within reasonable limit Summary ★ when there's something that's changing the acid base balance in the body, the first thing your body's going to do is use chemical buffers to maintain homeostasis ○ ACIDOSIS: ○ if imbalance is inside the cell, then buffers are proteins and phosphate o if imbalance is outside of the cell, then buffers are proteins and bicarb ○ ALKALOSIS: ○ proteins and phosphate inside the cell buffers base and proteins and H+ outside the cells (in blood) are bicarb buffer system ★ if chemical buffers can't maintain homeostasis, then the lungs get involved ○ lungs are able to take advantages of the equilibrium shifts it either makes CO2 or break down CO2 into its components ↑ acid = 1 CO2 → ↑ RR usually goes with compensating for acidosis for alkalosis, the only way to gain acids is to stop the release of CO2 → ↓ RR ★ Kidneys are the last mechanism the body uses to maintain acid-base balance ○ kidneys are unique in that they can fine tune the urine ○ they can choose to excrete the "bad stuff" and reabsorb the "good stuff" ○ ACIDOSIS: kidneys excrete acids (H+) and reabsorb bicarb to help neutralize any other acids in the blood ○ ALKALOSIS: kidneys excrete bicarbs and retain H+ acid to neutralize any bicarb left in the blood Anytime you have to excrete acid, you have to retain a cation (sodium) Anytime you get rid of a bicarb, you have to reabsorb a chloride Aldosterone: sodium reabsorption can cause the proton (H+) to be wasted List common causes of acid–base imbalances. What are sources of Acids and Bases? ★ Acids (exogenous or counterregulatory) ○ lactic acid from anaerobic metabolism ○ ketones from fat metabolism and protein ○ ASA ○ CO2 retention in gas exchange ○ if you loose base (e.g. diarrhea, use of diuretics) ★ Bases ○ antacids ○ black licorice ○ hyperventilation ○ vomiting ○ diuretics or renal dysfunction Metabolic Acidosis Metabolic Alkalosis Respiratory Acidosis Respiratory alkalosis ↓ pH ↓ HCO ↑ pH ↑ HCO ↓ pH ↑ PCO ↑ pH ↓ PCO Causes excessive production Excess loss of acids Any condition that Caused by excessive or intake of through GI tract or impairs gas exchange exhalation → loss of metabolic acid kidneys or lung ventilation CO in the body Ketoacidosis Massive blood (e.g., chronic Direct cause is always (diabetic, starvation, transfusion bronchitis, cystic hyperventilation (e.g., alcoholic) Diuretic therapy fibrosis, emphysema, too much mechanical lactic acidosis Bicarbonate retention pulmonary edema) ventilation, aspirin overdose Vomiting or gastric Predominantly due to pulmonary lesions) production/indigestion suctioning of hydrogen hypoventilation: Acute pain of acids chloride-containing COPD Acute anxiety or Severe diarrhea gastric contents Severe asthma; emotional distress causing loss of Ingestion of excessive Pneumonia Central stimulation of  bicarbonate from the amounts of sodium Pulmonary edema respiration by intestine bicarbonate Rapid, shallow inflammation (e.g., Circulatory Excess aldosterone breathing or from head injury or failure/hypovolemia (e.g., due to tumors) hypoventilation meningitis) Renal disease/failure Loss of gastrointestinal Narcotic or barbiturate Brain tumor or injury High ECF K+ hydrochloric acid and overdose Early stages of concentrations potassium (severe Injury to the brainstem congestive obstructive Shock vomiting or gastric Airway obstruction airway disease suctioning) Chest or head injury Asthma Over-use of K wasting diuretics Massive blood transfusion or bicarb transfusion S/S Weakness Dizziness CNS) anxiety, Dizziness Fatigue Decreased RR confusion, headache, Dry mouth Headache Numbness i notes and restlessness, blurry (CNS) numbness Dysrhythmias fingers vision, depression of /tingling in Kussmaul resp CVS dysrhythmia neural activity, (Motor) fingers and toes o tremors, and weakness increased neural (CVS) vasodilation due activity (seizures) to decreased pH, (CNS) flushed skin, warm vasoconstriction (Resp) whatever the (Resp) decreased RR, S&S of the original death issue is Signs of Hyperventilation Decreased Resps Increased excretion of Increased HCO3 Compen Hyperkalemia H+ via kidneys excretion sation Reabsorption of HCO3 in the renal system Analyze normal and abnormal blood gas levels. Normal Values pH: 7.35-7.45 PaCO₂: 35-45 – respiratory (lungs) HCO₃: 22-25 – metabolic (kidneys) Continuum of values – Acid vs Base (aka. alkaline) Acid: Base Base: Acid Acid: Base Example: pH 7.49, PaCO 62, HCO 46 Step 1 – Look at the pH and determine if it is Acid or Base or Normal pH 7.49 Base Step 2 – Look at the PaCO to determine if it is Acid, Base, or Normal PaCO 62 Acid Step 3 – Look at the HCO and determine if it is Acid, Base, or Normal HCO 46 Base Step 4 – Determine which value matches the pH interpretation pH – Base PaCO₂ – Acid (resp) HCO₃ – Base (metabolic) Whichever one matches the pH is the organ that’s the main involvement. Step 5 – Name the first part of the interpretation – Metabolic Alkalosis Step 6 – Determine amount of compensation – Full, Partial, or None If pH is in its normal range, it is fully compensated (the un-matching value will be opposite pH). If the un-matching value is out of range and opposite the pH value (e.g., above PaCO is showing acid number, not base) – there is partial compensation. If the un-matching value is normal, then there is no compensation. Apply holistic nursing care based on the concept of acid-base balance to clients needing chronic care management. Palliative approach: Provides key aspects of palliative care to individuals and families during an illness in all care settings Discuss the palliative approach with Bob's daughter, provide her with information such as palliative/hospice care, assess her ability and resources to provide care for Bob, encourage her to be part of the conversation and decision making. Consider stress relieving for her as well. From the case study, the daughter seems to be stressed and she does not know how to respond to the situation. Thus, she constantly watches the staff and tells them what to do. She could feel terrified and anxious regarding Bob's situation. Initiate an open and honest conversation with her to help her understand the care team's perspective and what we can do to help her. Goals of Palliative Approach Pain and Symptom Management: Alleviating physical symptoms such as pain, nausea, shortness of breath, fatigue, and other distressing symptoms, to enhance comfort. Emotional and Psychological Support: Providing psychological support to both patients and their families, addressing issues like anxiety, depression, and emotional distress that often accompany serious illness. Enhancing Quality of Life: Focusing on the patient’s physical, emotional, social, and spiritual well-being to ensure a life that is as fulfilling as possible, despite the illness. Facilitating Communication: Promoting open communication between the patient, their family, and the healthcare team about prognosis, treatment options, and care preferences, enabling informed decisions about care. Supporting Families and Caregivers: Offering support, education, and respite to families and caregivers who are often under significant stress as they assist in caring for their loved ones. Advance Care Planning: Assisting patients and families in discussing and making decisions about future care preferences, such as end-of-life wishes, through advance care directives and other planning tools. Holistic Care: Taking a comprehensive approach to care, addressing not only the physical needs but also the psychological, social, and spiritual aspects of the patient’s experience. Dignity and Respect: Ensuring that patients are treated with the utmost dignity and respect, allowing them to live their remaining days as fully and meaningfully as possible.