Question

5. IV of D5 1/2NS at 100 cc/hr. IV tubing drip factor is 20 gtts/ml. What is the gtts/min 6. A patient is started on furosemide (Lasix) to promote diuresis. Lasix 2,000 mg in 200 ml is prescribed at 1 mg per min. You should set the IV pump at how many ml per hour? 7. 500 ml DSW with 500 mg Aminophylline to infuse at 150 ml/hr (20 gtts/ml). How many drops per minute?

Answer 1

ANSWER.

5) Calculation of gtt/min.

         gtt/min = Volume(ml)/Time(min) * Drop factor(gtt/ml).

     Here

         Volume(ml) = 100 ml.

          Time(min) = 60 min (1hr)

         Drop factor = 20 gtt/ml.

As per above formula

          gtt/ml = 100/60 * 20

                     = 1.66 * 20

                     = 33.3 gtt/min.

6) Calculation of ml/hr.

             ml/hr = Volume(ml) / Time(hr).

       Calculation of volume(ml).

            Volume(ml) = Desired dose(D)/Dose in hand(H) * Quality(Q).

       Here

              Desired dose(D) = 1 mg/min.

              Dose in hand(H) = 2000 mg.

                   Quality(Q) = 200 ml.

As per above formula

            Volume(ml) of drug required = D/H * Q

                                                          = 1/2000 * 200

                                                          = 0.0005 * 200

                                                          = 0.1 ml.

                                          Time(min) = 1 min.

                 ml/min = 0.1 ml/min

     ml/min converted to ml/hr by multiply with 60 (1 hr = 60 min)

                 So

                      ml/hr = 0.1 * 60

                                = 6 ml/hr.

7) Calculation of drops per min.

         Drops per min(gtt/min) = Volume(ml)/Time(min) * Drop factor(gtt/ml).

      Here

          Volume(ml) = 150 ml.

          Time(min) = 60 min (1 hr).

          Drop factor = 20 gtt/ml.

As per above formula

         Drops per minute(gtt/min) = 150/60 * 20

                                                   = 2.5 * 20

                                                   = 50 gtt/min.