Acid base imbalance

Presesntation

1. Acid Base Balance Thara Noel MSc (N) Medical Surgical Nursing

2. ACIDS &BASES Acid Any compound which can give up a H⁺ ion in solution (proton donors) e.g. Carbonic acid releases H⁺ ions to form bicarbonate(HCO3-)• Base Any compound which can accept a H⁺ ion in solution (proton acceptors) eg:Bicarbonate(HCO3⁻) accepts H+ ions to form carbonic acid(H2CO3- )

3. ACID BASE BALANCE Normal pH : 7.35-7.45 Acidosis - Physiological state resulting from abnormally low plasma pH Alkalosis - Physiological state resulting from abnormally high plasma pH Acidemia: plasma pH < 7.35 Alkalemia: plasma pH > 7.45

4. REGULATION OF ACID-BASE BALANCE 1.CHEMICAL BUFFER SYSTEM Bicarbonate buffers Hemoglobin buffering system Phosphate buffers Bone buffers 2.RESPIRATORY REGULATION 3.RENAL REGULATION

5. BICARBONATE BUFFER SYSTEM The body cells constantly generate carbon dioxide Most carbondioxide,a by-product of cellular metabolism, is dissolved in the blood and converted to carbonic acid. Most of the carbonic acid then dissociates to  bicarbonate  and hydrogen ions.

6. BICARBONATE BUFFER SYSTEM

7. HEMOGLOBIN BUFFER SYSTEM CO2 diffuses across RBC membrane Bicarbonate ions diffuse into plasma in exchange for chloride ions (chloride shift) Hydrogen ions are buffered by hemoglobin molecules. Helps prevent major changes in pH when plasma PCO2 is rising or falling Phosphate Buffer System

8. HEMOGLOBIN BUFFER SYSTEM

9. ROLE OF LUNG AND KIDNEY IN ACID-BASE BALANCE

10. ACID BASE IMBALANCES

11. CLINICAL FEATURES Dyspnoea,Tachypnoea Restlessness, Confusion Diaphoresis,Lathargy Cyanosis Dilated Conjunctival and facial blood vessel Ventricular dysrrhythmias coma

12. TREATMENT Treat underlying cause Oxygen supplement CPT,Postural drainage Suctioning Intubation and mechanical ventilation Deep breathing exercise Antibiotics,Bronchodialators

13. CAUSES OF RESPIRATORY ALKALOSIS Direct stimulation of respiratory centre Anxiety,Fear,Pain Salicylates(stimulate respiratory center) Mechanical hyperventilation Intracerebral trauma Gram negative sepsis Pregnancy Hepatic insufficiency

14. CLINICAL MANIFESTATIONS Anxiety Light headedness Paresthesia Circumoral numbness Confusion Arrhythmias Tetany, Syncope Seizures

15. MANAGEMENT OF RESPIRATORY ALKALOSIS

16. METABOLIC ACIDOSIS Metabolic acidosis is defined as a pH less than7.35 with HCo3 less than22 meq/L Excessive acid loss Bicarbonate retention

17. CAUSES OF METABOLIC ACIDOSIS Loss of Bicarbonate Excess acid production Excess acid ingestion Inability of the kidney to excrete ion load

18. MANAGEMENT Treat underlying cause In DKA, Fluids and Insulin For CRF Hemodialysis, Peritoneal dialysis. Oral bicarbonate ,IV Sodium bicarbonate(2 to 5 mEq/kg IV infusion over 4 to 8 hours; subsequent doses should be based on patient's acid-base status)

19. CAUSES OF METABOLIC ALKALOSIS 1.HYDROGEN ION LOSSES Vomiting, Nasogastric suctioning Diuretics(Loop diuretics,Thiazide diuretics) Mineralo corticoids Hyper calcemia,Hypo parathyroidism Hypokalemia CHO Refeeding after starvation

20. Cont….. 2.BICARBONATE RETENSION Administration or Ingestion of Bicarbonate Massive blood transfusion Diuretics Cystic fibrosis

21. MANAGEMENT Treat underlying cause Treat hypokalemia with oral or IV Potassium salts Isotonic saline infusion to correct volume deficits Azetazolamide in congestive heart failure