Fluid and Electrolytes: Balance and Disturbances?

[fathertod, ASN, BSN, MSN, APRN, NP]

Conrad Jackson is a 28-year-old male who presents to the Emergency Department with severe fatigue and dehydration secondary to a four-day history of vomiting. During the interview, he describes attending a family reunion and states that perhaps he "ate something bad." Upon admission his vital signs are a temperature of 102.7, pulse of 116, respirations 18, and blood pressure of 86/54. The nurse also notes the patient has dry mucous membranes and tenting of skin. The physician orders an IV to be started with 0.45% normal saline, and orders a serum electrolytes and an arterial blood gas. The following results are returned from the laboratory:

Sodium (Na+) 150

Potassium (K+) 5.5

Chloride (Cl-) 110

BUN 42

Creatinine 0.8

Glucose 86

pH 7.32

PaCO2 35

HCO3- 20

PaO2 90

O2 Sat 98%

What is your interpretation of this arterial blood gas sample?Why would the patient have these arterial blood gasses after vomiting? Explain the high potassium? Why use .45 NS?

[PurrRN]

What is your interpretation of this arterial blood gas sample?Why would the patient have these arterial blood gasses after vomiting? Explain the high potassium? Why use .45 NS?

Since this is an obvious case study you want help with, why don't you start out with what you think is going on and people can comment on that?

Looking at strictly the ABG's and also s/s of vomiting can give you a clue as to what is going on in this cs.

[Daytonite, BSN, RN]

potassium (k+) 5.5

ph 7.32

paco2 35

hco3- 20

pao2 90

o2 sat 98%

these values are consistent with a patient who is dehydrated and in acidosis. the ph tells you he is in acidosis. however, the co2 which is the value that you look at in conjunction with acidosis is at the low end of normal range, so he is bordering on metabolic acidosis. potassium levels always go up when there is acidosis. 1/2 normal saline (0.45 normal saline) is the only hypotonic iv solution. it will cause water to be pulled into the cells which is what a dehydrated (symptoms: low b/p, dry mucus membranes, tenting of the skin, elevated bun) person needs.

there are tutorials and help on fluid and electrolytes and abgs on posts #24, #25 and #46 of this sticky thread:

• https://allnurses.com/forums/f205/pathophysiology-p-fluid-electrolyte-resources-145201.html - pathophysiology/ a & p/ microbiology/ fluid & electrolyte resources (in nursing student assistance)

[yoginurse2b]

pH 7.32 (acidosis)

HCO3 20 (decrease base)

PaCO2 35 (normal)

ABG = metabolic acidosis with no compensation

Reason: pt is dehydrated and having fever (hypermetabolism = increase H production). Although vomiting (decrease acid component) can lead to metabolic alkolosis, it only happens during a prolonged period.

Remember: Acidosis = Hyperkalemia; Alkalosis = HypoK and HypoCa (Low potassiu and calcium)