HYPOKALEMIA HYPOKALEMIA John Pacy 13918 BASIC Total body K+ 50mEqKg K+ in Intracellular fluid 98% K+ in Extracellular fluid 2% Plasma accounts for 20% of extracellular fluid K+ in plasma = 0,4% t.HYPOKALEMIA HYPOKALEMIA John Pacy 13918 BASIC Total body K+ 50mEqKg K+ in Intracellular fluid 98% K+ in Extracellular fluid 2% Plasma accounts for 20% of extracellular fluid K+ in plasma = 0,4% t.
HYPOKALEMIA John Pacy 13/9/18 BASIC • Total body K+: 50mEq/Kg: - K+ in Intracellular fluid: 98% - K+ in Extracellular fluid: 2% Plasma accounts for 20% of extracellular fluid K+ in plasma = 0,4% total body K+ Ex: a 50 kg person: 2500mEq total body K+ K+ plasma: 10mEq The relationship between total body K+ and serum (plasma) K+ • In an adult with a normal serum K+ of mEq/L: Total body K+ deficit of 200–400 mEq plasma K+ of mEq/L Total body K+ excess of 100–200 mEq plasma K+ of mEq/L Brings to home: • The change in total body K+ with K+ depletion (hypokalemia) = x the change with K+ excess (hyperkalemia) • K+ is lost in stool (5-10 mEq/d), swear(0-10 mEq/d), and the major lost is in urine (40-120 mEq/d), depending on K+ intake • K+ is: - Filtered at the glomerulus - Passively absorbed in the proximal tubules - Secreted in the distal tubules and collecting ducts - Potassium excretion in urine is controlled by plasma K+ and aldosteron HYPOKALEMIA Serum K+ 3.0 to 3.5 mEq/L and symptoms or signs attributable to hypokalemia have resolved reduced or changed to oral therapy Hypomagnesium • If the hypokalemia is resistant or refractory to K+ replacement, magnesium depletion should be considered • In mild to moderate hypomagnesemia (1.0 to 1.5 mg/dL), to g of magnesium sulfate IV at a maximum rate of g/hour • In severe symptomatic hypomagnesemia, to g of magnesium sulfate can be administered IV over to 60 minutes 10 Things To Remember… K+ in plasma = 0,4% total body K+ Decreased intake alone rarely causes significant hypokalemia In most cases, hypokalemia is asymptomatic 10 Things To Remember… Hypokalemia can cause life-threatening dysrhythmias: VT, VF, TDP if the ECG has manifestations of hypokalemia, including ST depression, prolonged QT and U-waves, that the risk of dysrhythmias is higher 10 Things To Remember… Rule out any condition that promotes transcellular potassium shifts Remember to check BP, acid – base, urine chloride when hypokalemia is due to potassium depletion to determine causes About 10% of total body K+ is lost = every mEq/L decrease in serum K+ 10 Things To Remember… ampules KCL 10% 10ml (~ 30 mEq K+) and NaCl (non-dextrose) 0,9% 500ml IV peripheral in h and check potassium serum concentration every hours 10 If the hypokalemia is resistant or refractory to K+ replacement, magnesium depletion should be considered Questions?? • Name categories that cause hypokalemia? • Name the causes which belongs to group “transcellular shifts”? • Name the causes which belongs to group “potassium depletion”? • Name the clinical manifestations of hypokalemia? • Name the ECG abnormalities of hypokalemia? • Name the causes that present “prolongation QT” on ECG? • When and how we use the oral therapy? • When and how we use the IV therapy? How to follow –up? ... significant hypokalemia In most cases, hypokalemia is asymptomatic 10 Things To Remember… Hypokalemia can cause life-threatening dysrhythmias: VT, VF, TDP if the ECG has manifestations of hypokalemia, ... hypokalaemia Long QU interval in hypokalaemia • However, these changes are not specific for hypokalemia • Prolonged QT: - Hypokalemia, Hypomagnesemia, Hypocalcemia, Hypothermia - Acute myocardial ischemia... that the risk of dysrhythmia due to hypokalemia is higher than without hypokalemic ECG abnormalities? • Very little data correlating the ECG with dysrhythmias in hypokalemia • He personally have