NCLEX Saunders: Acid Base Balance Chapter #9

What is the pH scale?

A scale used to determine how many hydrogen ions are in the body fluid. Goes from 1 to 14 with 7 being neutral.

The pH of body fluid should be maintained within what range?

7.35-7.45

How do the lungs assist in acid base balance?

In an acidotic state the lungs will increase the RR to excrete more CO2.In an alkalotic state the body will decrease the RR to hold on to more CO2 (acid).

How do the kidneys assist in acid base balance?

During acidosis, the kidneys will secrete more hydrogen ions into the tubules to excrete the acid through the urine.During alkalosis, the kidneys will move bicarbonate into the tubules and out through the urine.

In a pt. with an acid base imbalance the nurse most closely monitor which electrolyte level? Why is this important?

Potassium; this electrolyte moves in or out of the cells in attempt to maintain acid base balance.With a K+ imbalance the pt. is at significant risk of complications such as dysrhythmias and other cardiac concerns... put them on an EKG.

During an acidotic state what happens to K+ levels?During an alkalotic state what happens to K+ levels?

Acidotic state: Hydrogen ions must enter the cell and leave the blood stream, causing K+ levels to leave and make room from them causing hyperkalemia. (K+ gets excited)Alkalotic state: Hydrogen ions rush into the blood stream and K+ levels take their place, causing hypokalemia. (K+ gets bored)

What happens to the RR in acidosis?What happen to the RR in alkalosis?

In acidosis the body attempts to compensate by increasing the RR to excrete the extra CO2.In alkalosis the body attempts to compensate by decreasing the RR to retain as much CO2 as possible.

What happens to the CNS in acidosis and in alkalosis?

CNS matches the direction of RRAcidosis: LOW RR, LOW suppressed CNS- Lethargy, confusion, dizziness, headache, seizure, coma. Alkalosis: High RR, High excitable CNS- Lethargy, Confusion, Lightheadedness, dizziness, headache, tingling of extremities, tetany, tremors.

Respiratory Acidosis:Causes:Assessment:Interventions:

Causes:Any condition that obstructs gas exchange, or decrease the RR.- Asthma, COPD, emphysema, Pulmonary Embolism, pneumonia, CNS depressant Assessment:- This will be dependent on the disease that is causing it- Hypoventilation with hypoxia- Behavior changes, acidotic condition = decrease in the CNS: lethargy, confusion, dizziness, headache, seizure, coma.- Hyperkalemia, r/o dysrhythmiasInterventions: The main goal is to improve respiratory ventilation; get that CO2 out!- Improve ventilation- Positioning the pt. appropriately - O2 prn- Turn frequently, and CDB- Suction prn (airway obstruction may be due to sputum) - Treat the cause (ex. Asthma-bronchodilator, pneumonia-antibiotics, provide hydration to loosen secretions)- Mechanical ventilation (set the RR and depth). This is typically required if the PaCo2 is > 50

True or False:A non-rebreather mask is a treatment option for a pt. experiencing respiratory acidosis.

False!This would cause them to retain even more CO2.

Respiratory Alkalosis:Causes:Assessment:Interventions:

Causes: Any condition that causes hyperventilation/high RR- Panic attack/hysteria- Pain- Hypoxia- Overventilation by mechanical ventilator- FeverAssessment:- Tachypnea- Change in behavior: CNS excitable: lethargy, dizziness, confusion, lightheadedness, irritability, tetany, numbness, paresthesia's, twitches,- Hypokalemia; r/or dysthymias, put them on EKGInterventions: The goal is to decrease the RR- Breathing exercises: voluntary holding of breath, using a rebreather mask, using a paper bag).- If the ventilator is the issue, decrease the RR on the machine- CNS depressants prn

Intestinal contents/bowel are more acidic or basic?

They are BASIC once they get to the bowel.

Metabolic Acidosis:Causes:Assessment:Interventions:

Causes: - Loss of bicarbonate (ex. diarrhea)- Build up of acid (ex. lactic ACID is produced when there's a lack of O2) prolonged lack of O2; ex. alcohol--liver disease which produces a build up of acid/toxins, burns, sepsis, shock.- Build up of ketones: DKA, no glucose so fats are burned instead; ketones which are an acid.- Renal failure; can't pee put acidic urine- Excessive ingestion of acetylsalicylic ACID (aspirin) causes an increase in the hydrogen concentration.Assessment: Dependent on cause- Changes in behavior: acidotic condition = decrease in the CNS: lethargy, confusion, dizziness, headache, seizure, coma.- Hyperkalemia; r/o dysrhythmias- Deep rapid respirations (coping mechanism) this is called Kussmal's respirations.- Nausea and vomiting (standard for all acid base imbalances)Nursing Interventions:- Treat the underlying cause (ex. renal failure -- dialysis, shock-- vasopressors) - Assess LOC, keep them safe- Monitor I&O and labs (ABG's, K+, organ function)- Supportive therapy: fluids, O2 prn, maintain electrolytes, give bicarb)

What are Kussmauls Respirations?

Respirators are abnormally deep and increased in rate. This is a compensatory action of the longs commonly seen in diabetic ketoacidosis; trying to expel the extra CO2.

The client with excessive diarrhea is at risk for which acid base imbalance?The client with diabetic ketoacidosis is at risk for which acid base balance?The client with vomiting or NG tube suctioning is at risk for which acid base balance?

Diarrhea: Metabolic Acidosis DKA: Metabolic AcidosisVomiting/NG: Metabolic alkalosis

High consumption of acetylsalicylic acid (aspirin) is likely to cause which acid base imbalance?

Metabolic acidosis

Metabolic Alkalosis:Causes:Assessment:Interventions:

Causes: - Diuretics; peeing off all of the hydrogen- Vomiting/NG tube suctioning; losing all gastric acid- Antacids: neutralizes acids ex. Tums- Over administration of sodium bicarbonate- Hyperaldosteronism; the increase in Na+ causes a loss of hydrogen ions- Massive transfusion of whole blood: the preservative for whole blood is sodium bicarbonate Assessment:- Dependent on the cause- EKG changes due to hypokalemia, r/o dysrhythmias- Hypoventilation (coping mechanism)- Tetany (risk of seizures) hypokalemiaNursing Interventions:- Stop the trigger (ex. antiemetics, reduce suction, etc)- Monitor for respiratory distress and circulatory collapse- Assess LOC and keep them safe- Monitor I&O, and labs (ABGs, and K)- Supportive therapy: fluids, O2 prn, replacement of K, meds that support excretion of HCO3.

What is the nurses role in obtaining an ABG collection?

Usually conducted by an RTNurse:- Collect VS- Determine if an arterial line is already in place in which you can take a sample from instead- Perform the Allen's test; this tells us if the ulnar artery is strong enough on it's own to perfuse the entire hand prn- Assess factors that hinder the accuracy of results: suctioning within the last 20 min, changes in the O2 settings, client activities).- Pressure needs to be applied immediately to the puncture site (arteries carry way more pressure than veins) hold pressure for 5 minutes or 10 min for a pt. on anticoagulants. Reassess the radial pulse after applying pressure.

What are the normal ranges for the following arterial blood values?pHPaCo2HCO3PaO2

pH 7.35-7.45PaCo2 35-45HCO3 22-26PaO2 80-100Pa = peripheral artery

How would you know if full compensation has occured?

The pH will be within normal range, pH 7.35-7.45

The most accurate way to objectively determine a pt. ventilation and oxygenation status is to:

Obtain an ABG