Surgery and Anesthesia Math Practice

Math you MUST know for surgery: (this is not all the math you need for the VTNE or being an LVT in practice)

*Round all weights to at least two decimal places!

  • (Weight x dose) / concentration = mls of drug needed
  • Surgical fluid maintenance rates (ml/hr AND gtt/sec)
  • Dog and cat doses
  • Shock doses for isotonic crystalloids and colloids (hetastarch) (total mls)
  • Dog and cat doses
  • Rehydration calculation (total mls)
  • CRIs (total mls of drug needed)
  • Oxygen flow rate (L/min)
  • Rebreathing and non-rebreathing systems (ml/kg/min)
  • Reservoir bag calculation (in Liters)
  • Time left of oxygen in tank based on psi and flow rate (hours or minutes)

Please answer on a separate sheet of paper, show all of your work, and include units.

It would be helpful if you box or underline your answers 

Practice problem #1: Dog = 18 kg 6% dehydrated 15 gtt/ml set

  1. What breathing system do you need?
  2. What size reservoir bag?
  3. What will the oxygen flow rate be?
  4. How much time left if E tank is at 1500 psi?
  5. How much acepromazine needed at 0.04 mg/kg, 10 mg/ml?
  6. Amount of fluid to replace before surgery?
  7. Surgical maintenance rate in ml/hr? In gtt/sec?
  8. Total initial bolus amount of hetastarch if in hypovolemic shock?
  9. Vet wants 100 mg/ml morphine at 2 mg/kg/hr and a 40 ml/hour flow rate. You have a 1L bag of LRS. How many mls of morphine need to be added to the fluid bag?

Practice problem #2: Cat = 8.5lb 5% dehydrated 60 gtt/ml set

  1. What breathing system do you need?
  2. What size reservoir bag?
  3. What will the oxygen flow rate be?
  4. How much time left if E tank is at 700 psi?
  5. How much ketamine needed at 4 mg/kg, 10 mg/ml?
  6. Amount of fluid to replace before surgery?
  7. Surgical maintenance rate in ml/hr? In gtt/sec?
  8. Total ini--0000000tial bolus amount of hetastarch if in hypovolemic shock?
  9. Vet wants 2% lidocaine at 20 micrograms/kg/min and a 10 ml/hour flow rate. You have a 500 ml bag of Normasol. How many mls of lidocaine need to be added to the fluid bag?

Practice problem #3: Dog = 30 lbs 7% dehydrated 15 gtt/ml set

  1. What breathing system do you need?
  2. What size reservoir bag?
  3. What will the oxygen flow rate be?
  4. How much time left if E tank is at 250 psi?
  5. How much propoflo needed at 1 mg/lb, 100mg /10 ml?
  6. Amount of fluid to replace before surgery?
  7. Surgical maintenance rate in ml/hr? In gtt/sec?
  8. Total initial bolus amount of hetastarch if in hypovolemic shock?
  9. Vet wants 40 mg/ml dopamine at 0.3 mg/kg/hr and a 50 ml/hour flow rate. You have a 1L bag of Plasmalyte. How many mls of dopamine need to be added to the fluid bag?