Question

A critical care patient with meningitis is receiving 500 mL of D5LR every 8 hours. He has new orders for ceftriaxone to be dosed at 45 mg/kg/day in three divided doses in 50 mL D5W IVPB over 30 minutes. The patient who weighs 110 lb is on a 1500 mL/day fluid limit. What is the flow rate of the D5LR in drops/minute if the administration set delivers 15 drops/mL? (answer rounded to nearest whole number.) Can you explain why you solve the way you solve.

Answer 1

Patient is receiving D5LR by primary line and IVPB (IV Piggy Beg) is attached as secondary line with ceftriaxone in given dose. In this case patient would receive extra 50ml of fluid for 30minutes three times in a day. This is extra fluid which would be given to patient.

( Hrs in a day = 24 hrs)

Total extra fluid (other than D5LR) = 50ml × 3 = 150ml

Total time IVPB would take for infusion this extra fluid

30min × 3 = 90minutes

IVPB hanged on height than primary D5LR . So when IVPG would be giving drug in in thus extra fluid , primary line would not work.

Here maximum limit for this patient to give fluid is 1500ml/day.

He was receiving D5LR 500ml in every 8Hrs

So he was receiving D5LR = 500ml× 3 = 1500ml /24 hrs (day)

So now when patient would be started with ceftriaxone in 50ml every 8hrs. We have to decduct this extra 150ml fluid from D5LR

So total D5LR would be given in 24 Hrs is

1500ml -150 ml = 1350ml

We have to give 1350ml D5LR

When ceftraixone would be given in 50ml ,primary ine would not give fluid (D5LR) . To adjust flow rate of of D5LR we have to deduct that time period when ceftriaxone would be given by IVPB that is 90min (calculated above)

24Hrs - 90Min

24×60 - 90 (1hr = 60min)

1440 -90 = 1350 min

So total D5LR delivery to the patient would be 1350ml in 1350 min.

1350ml/1350min = 1ml/min

Primary IV line of D5LR would be set on 1ml/min

If 1ml have 15 drops (given in queation) than

1ml/min × 15 = 15drops/min

Primary line would be set on 15 drops/min in this case with starting IVPB.

I explained in calculations why i use this way to solve. We should have the knowledege of IVPB (Intra venous piggy Beg) to solve this question. IVPB comes with medicine in it with recommended fluid (Distilled water or D5 or NS) volume on it. It is attached with primary line and keep higher than Primary fluid beg. So pressure from the IVPB is more than Primary beg. Thus when the IVPB contain fluid/medication, it delivers to patient and primary line stopped. As soon as IVPB empty Primary line again started.

Here we know that how much time IVPB would take and How much Volume it wpuld give to patient. So we deduct both these from require volumne of fluid and time . And calculated the flow rate.