NCLEX study review question

[delabeaux, MSN]

I'm studying for the NCLEX, which I will take after I graduate in December.

While studying metabolic acidosis, under interventions, it lists, "Monitor potassium and calcium serum levels". I understand why we would check potassium as it moves from intravascular spaces to intracellular spaces creating a relative hypokalemia, but I did not see in my studying why we would monitor calcium.

Thoughts? I"m studyhing Saunder's Comprehensive NCLEX Review, Edition 5.

Thanks in advance.

[**LaurelRN, MSN]

During metabolic acidosis calcium is released from bone in an attempt to neutralize the excess acids and stabilize the body's pH level. The calcium and acids are then excreted in the urine. This calcium loss from bone leads to weak, brittle bones.

Additionally, remember- that Calcium and Phosphorus go hand in hand- they are opposites- so if your Calcium is high- your phosphorus will be low. Remember to monitor ECG rhythm- specifically QT interval, LOC_ pts will get irritable, confused and have a dec LOC in late stages- lastly, hyporeflexia and muscle weakness and fatigue are symptoms of both hypophosphatemia and hypercalcemia

Hope this helps

[NIGHTINGALE-RN]

Hi Delabeaux,

If you are studying for nclex then besides practicing questions, try to think about pathophysiology in our body too. Understanding of good electrolytes is important and will help you a lot in answering questions.

Metabolic acidosis indicates imbalance of ph level in body. Calcium and phosphorus in our bones and fluid are buffering systems which try to neutralize the acidity produced by acidosis and try to balance ph, the lab monitoring of calcium will show how far its working.

Infact calcium and magnesiums act like sedatives for our body muscles and which includes heart also and normal amounts also prevent abnormal DTR's in our body.

K, Ca, Mg, are most important electrolytes affecting our body esp heart.

hope this helps

[kainos]

Hmmm... I just had a peds clinical pt (12 yo male) who came in with DKA. He was hypokalemic (lowest was 2.4) and hypo- (not hyper) calcemic. Maybe that's just an anomaly - any thoughts? I think I remember my Mosby lab book suggesting that hypo occurs with both Ca & K in DKA d/t osmotic diuresis. I guess diuresis totally changes the game when it comes to DKA & e-lytes.

[kainos]

Okay - you'll really want to read this... Metabolic acidosis actually causes a relative serum HYPERkalemia (not hypo). Read the section "General Physiologic and Metabolic Effects":

http://emedicine.medscape.com/article/906440-overview#a0104

It also explains how this hyperkalemia affects the ECG. This makes sense now. I remember my teacher telling us that if a pt has DKA, even if the potassium lab is high (it likely could be high d/t the acidotic state pushing potassium out of cells), the pt will still require potassium replacement because once the DKA is corrected the potassium will be pushed back into the cells and then the serum potassium level will drop into the hypo- range because of the potassium that was lost via diuresis during the DKA episode.

I think my pt's potassium was low because they drew that lab after they had already been correcting the DKA.

[delabeaux, MSN]

Okay - you'll really want to read this... Metabolic acidosis actually causes a relative serum HYPERkalemia (not hypo). Read the section "General Physiologic and Metabolic Effects":

http://emedicine.medscape.com/article/906440-overview#a0104

It also explains how this hyperkalemia affects the ECG. This makes sense now. I remember my teacher telling us that if a pt has DKA, even if the potassium lab is high (it likely could be high d/t the acidotic state pushing potassium out of cells), the pt will still require potassium replacement because once the DKA is corrected the potassium will be pushed back into the cells and then the serum potassium level will drop into the hypo- range because of the potassium that was lost via diuresis during the DKA episode.

I think my pt's potassium was low because they drew that lab after they had already been correcting the DKA.

Thanks for the great posts, and great catch... I was reading Acidosis and thinking alkalosis when I wrote relative hypokalemia!

Also, thanks for the patho tip... I want to hit my head and say D'Oh!. I knew the body tries to neutralize excess acid with 'leeched' calcium from the bones, I just didn't apply it to this.

Again thanks!

~bb

[NurseLoveJoy88, ASN, RN]

Because I'm a nerd and have no life I looked up this up in my medsurg book. Short answer is that a decreased plasma ph ( acidosis) causes a decreased in calcium and increased ph ( alkalosis) causes increased calcium levels.

[caliotter3]

You might be delving too far into the information. For the NCLEX, it is most likely that just knowing these must be monitored is sufficient. Otherwise the review material would give you the nuts and bolts down to this level. Save the in depth analysis for after the test.

[ag11]

i always just figured that w/ metab acidosis the pt has diarrhea and w/ diarrhea we lose electrolytes and CA is one of them..this was the way i used to understand it when applying the material.