Hypokalaemia.pptx

CORSE OF HYPOKALEMIA

1. Hypokalaemia Dr REBAHI FAYCAL ANESTHESIA ICU

2. Potassium is the most abundant intracellular cation Only about 2 % of total body potassium is in the ECF Intracellular potassium is responsible for maintaining cell volume and resting membrane potential. normal 3.5–5.5 mmol /L

3. Defined as plasma concentration of K+ < 3.5 mEq /L Mild Hypokalemia 3.0 – 3.5 mEq /L Moderate Hypokalemia < 3.0 mEq /L Severe Hypokalemia <2.5 mEq /L Hypokalaemia

4. Neuromuscular problems include GI hypomotility skeletal muscle weakness or paralysis rhabdomyolysis . . Clinical manifestations

5. 2. Cardiac manifestations ventricular and atrial dysrhythmias predisposition to digoxin toxicity cardiac necrosis ECG changes

6. Effects of hypokalaemia on the ECG Increased amplitude of the P wave Prolongation of the PR interval T wave flattening and inversion ST depression   U wave (best seen in the precordial leads)  long QT interval due to fusion of the T and U waves (= long QU interval)

7. 3 . Renal manifestation Cellular metabolism and renal function can also be impaired.

8. Differential Diagnosis Hypokalemia can result from (a) Decrese intake (b)shifting of potassium into cells (c) renal wasting (c) extra renal losses

9. (b) Intracellulaire shift Médications ( β2 agonists , phosphodiesterase inhibitors , calcium channel blockers exogenous insulin ) Hyperthyroïdisme alkalosis familial periodic paralysis ( a)Decreased intake : Inadequate dietary potassium intake (e.g. alcoholism, anorexia)

10. (c) GI loss Diarrhea NG losses vomiting (d) Renal loss medications ( diuretics , exogenous mineralocorticoids , penicillin , cisplatin ) Mineralocorticoid excess ( primary hyperaldosteronism , Cushing disease , renin secreting tumors )

11. Management 1. Treat underlying cause 2. Replace potassium—oral or intravenous . Central line preferred for intravenous replacement Rate (20 mEq KCl in 100 cc NS—infuse at 10-20 mEq /h) 3. Monitor ECG

12. IV infusion rate 10 - 20 meq / hour Standard IV replacement rate symptomatic hypokalemia 20 - 40 meq / hour Sérum potassium < 2.5 meq /L or moderate - severe symptômes > 40 meq / hour Serum potassium < 2.0 Meq /L