Math help from the Learning Centre

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

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

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 - 4 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 am to 4 pm. The IV is held for 2 hours while 40 mL of 20 mEq D5W is administered from 12 pm to 2 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 (4 pm - 1 am)

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. 

The fluid balance is equal since total intake = total output