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Math help from the Learning Centre

This guide provides useful resources for a wide variety of math topics. It is targeted at students enrolled in a math course or any other Centennial course that requires math knowledge and skills.

Breaking it down

Fluid balance is calculated by total intake - total output
When intake is greater than output, the result will be positive (+)
When intake is less than output, the result will be negative (-)
When intake is equal to output, the result is equal (=)

Step 1) Identify inputs 

  • Oral: any liquids
  • IV: infusions, normal saline
  • IV med
  • TPN

Step 2) Identify outputs 

  • Urine: void, urine, foley catheter
  • Emesis
  • Stool
  • Drainage: wound, surgical, fistula

Examples

Example 1

During a 12-hour shift from 0600H - 1800H, patient X had 40 mL/h of IV infused starting from 0600H. An order to increase the IV fluids to 55 ml/h was received at 1200H. The IV infusions stopped at 1500H while TPN was administered at 25 mL/h. Patient X drank 120 mL of water at 0700H along with 3 cookies weighing 15 g. At 0900H, the patient had 200 mL of liquid feces. The patient had 20 mL of ice chips and 5 mL of ice pop at 1230H. The patient ate at 1400H and had a sandwich, 100 mL of juice, 20 mL of ice cream and one cup of water. At 1600H the patient went to the bathroom to void 150 mL of urine and 40 mL of emesis. Finally, at the end of the shift, 80 mL was emptied from the patient's surgical drain. Fill in the I&O table and find the fluid balance.

Solution

Step 1) Highlight/identify the inputs, volume, time

During a 12-hour shift from 0600H - 1800H, patient X had 40 mL/h of IV infused starting from 0600H. An order to increase the IV fluids to 55 ml/h was received at 1200H. The IV infusions stopped at 1500H while TPN was administered at 25 mL/h. Patient X drank 120 mL of water at 0700H along with 3 cookies weighing 15 g. At 0900H, the patient had 200 mL of liquid feces. The patient had 20 mL of ice chips and 5 mL of ice pop at 1230H. The patient ate at 1400H and had a sandwich, 100 mL of juice, 20 mL of ice cream and one cup of water. At 1600H the patient went to the bathroom to void 150 mL of urine and 40 mL of emesis. Finally, at the end of the shift, 80 mL was emptied from the patient's surgical drain.

  • IV 
    • 40 mL/h from 0600H to 1200H
    • 55 mL/h from 1200H to 1500H
  • Oral (note solid foods are not accounted for)
    • 120 mL of water at 0700H
    • 10 mL of ice chips (half volume) at 1230H
    • 5 mL of ice pop at 1230H
    • 100 mL of juice at 1400H
    • 20 mL of ice cream at 1400H
    • 240 mL (converted one cup) of water at 1400H
  • TPN
    • 25 mL/h from 1500H to 1800H

Step 2) Highlight/identify the outputs, volume, time

During a 12-hour shift from 0600H - 1800H, patient X had 40 mL/h of IV infused starting from 0600H. An order to increase the IV fluids to 55 ml/h was received at 1200H. The IV infusions stopped at 1500H while TPN was administered at 25 mL/h. Patient X drank 120 mL of water at 0700H along with 3 cookies weighing 15 g. At 0900H, the patient had 200 mL of liquid feces. The patient had 20 mL of ice chips and 5 mL of ice pop at 1230H. The patient ate at 1400H and had a sandwich, 100 mL of juice, 20 mL of ice cream and one cup of water. At 1600H the patient went to the bathroom to void 150 mL of urine and 40 mL of emesis. Finally, at the end of the shift, 80 mL was emptied from the patient's surgical drain.

  • Stool
    • 200 mL at 0900H
  • Urine
    • 150 mL at 1600H
  • Emesis
    • 40 mL at 1600H
  • Drain
    • 80 mL at 1800H
Intake 6-7 7-8 8-9 9-10 10-11 11-12 12-1 1-2 2-3 3-4 4-5 5-6 Total
IV 40 mL 40 mL 40 mL 40 mL 40 mL 40 mL 55 mL 55 mL 55 mL       405 mL
Oral   120 mL         15 mL   360 mL       495 mL
TPN                   25 mL 25 mL 25 mL 75 mL
Shift total 40 mL 160 mL 40 mL 40 mL 40 mL 40 mL 70 mL 55 mL 415 mL 25 mL 25 mL 25 mL 975 mL
Output 6-7 7-8 8-9 9-10 10-11 11-12 12-1 1-2 2-3 3-4 4-5 5-6 Total
Stool       200 mL                 200 mL
Urine                     150 mL   150 mL
Emesis                     40 mL   40 mL
Drain                       80 mL 80 mL
Shift total       200 mL             190 mL 80 mL 470 mL

The fluid balance would be total intake (975 mL) minus total output (470 mL)

975 - 470 = +505 (positive since total intake > total output)

Example 2

The day nurse uses the following information to complete the day record (7 am - 3 pm)

The patient eats an apple, 45 mL of milk and 13 g of cereal for breakfast. He has 20 mL/h of IV infusing from 9:00 am to 2:00 pm. The IV is held for 2 hours while 40 mL of 20 mEq D5W is administered from 12:00 pm to 2:00 pm. During lunch, he eats 3 oz of ice chips, a salad and 2 slices of bread. 400 mL was emptied from his foley catheter near the end of his shift. 

The night nurse uses the following information to complete the night record (3 pm - 11 pm)

Throughout the whole shift, 10 mL/h of IV was administered. Before dinner, the patient was feeling unwell and vomited 120 mL of emesis. He then ate a sandwich and drank 300 mL of hot tea. Before heading to bed, 210 mL was emptied from his foley catheter and he had 5 tablespoons of pudding. 

Intake
Shift Oral IV Other Total
Day 90 mL 60 mL 40 mL 190 mL
Night 375 mL 80 mL   455 mL
Total 465 mL 140 mL 40 mL 645 mL
Output
Shift Urine Emesis Other Total
Day 400 mL     400 mL
Night 210 mL 120 mL   310 mL
Total 610 mL 120 mL   730 mL

The fluid balance is equal since total intake = total output

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