Paediatric. Intravenous Therapy. And. Drug Administration. Pre I.V. Course Workbook

Transcription

1 Paediatric Intravenous Therapy And Drug Administration Pre I.V. Course Workbook Name:.... Preceptor:... Please return completed workbook to Annette Watsulu. By:.... 1

2 This workbook consists of three sections Section One: involves clinically related drug calculations. Section Two: presents a number of clinical scenarios, which require demonstration of problem-solving skills. Please complete ALL the questions. Do not hesitate to seek advice and support from your clinical colleagues. A reference list is also provided for you at the end of the workbook. The workbook must be completed before you attend the IV. Study day in the Faculty 2

3 Section 1 The following section is intended to prepare you for the drug calculations examination. There are some worked examples followed by similar questions for you to complete. For the purposes of the examination, you will be allowed to use a calculator, and a list of standard formulae will also be provided. Conversions Some drug calculations involve the use of different units of measurement (for example micrograms and milligrams). It is essential for calculating the dose to be administered that all units are the same. Example: Convert 0.5 milligrams to micro grams There are a thousand micro grams in 1 milligram. Therefore you need to multiply by 1000 and the decimal point moves three places to the right 0.5 milligrams x 1000 = 500 micrograms Question 1: Convert milligrams to micrograms Answer: Example: Convert 625 micrograms to milligrams There are 1000 micro grams in a milligram, but in this case you nee to divide by 1000 and the decimal point moves 3 places to the left (you are moving from a smaller to a larger unit of measurement) 625 micrograms mil1igrams Question 2: Convert 25 micrograms to milligrams Answer: 3

4 Dosage Calculations These are required when the amount actually needed is not the same as the amount in the stock ampoule or vial. Example: You need to give Gentamycin 60mgs IV. You have available a vial containing 80mgl2mls. Formula What you want / what you've got X what it s in (volume) 60 / 80 x 2 = 1.5mls Question 3 You need to prepare an infusion of Vancomycin containing 100 mg. Vancomycin comes as 5OOmg vial. You need to add 9.7mls of water for injection to give a concentration of 5Omglml. This needs to be further diluted to give a dilution of 5mglml. How many mls will the final volume be? 4

5 Drugs Expressed as Ratios Adrenaline Example: You have Adrenaline 1: 10,000 You need to give 0.5mgs stat. How many mls would you give? Answer: Adrenaline 1:10,000 = 1 gram in 10,000mls = 1000mg in 10,000 mls = 1mg in 10mls Dose required = 0.5 mgs What you want / what you've got X volume 0.5 / 1 X 10 = 5mls Question 4 You need to give a patient 10mcg/kg of adrenaline 1:10,000. The child weighs 10kg. How many mls will you need to give the patient? 5

6 Percentages Some fluids/drugs are expressed as percentages e.g. Sodium Bicarbonate, Mannitol, Lidocaine etc. However, they can be prescribed in dosages expressed as grams/milligrams and in paediatrics in mls. Example: Mannitol 10% = 10 grams in 100mls Mannitol 20% = 20 grams in 100mls I.e. the % = grams per 100 mls Give 20 grams of Mannitol I.V. stat. You have Mannitol 10% Mannitol 10% = 10 grams per 100 mls What you want / what you've got X volume 20 / 10 X 100 = 200mls Question 4 Give 50 grams of Mannitol I.V. stat. You have Mannitol 20% Answer: Question 5 a) How many grams of Sodium Bicarbonate 8.4% in 50mls. b) An infant has a metabolic acidosis with a Base Deficit = -16, wt 4 kg Half correction is achieved by: mmol bicarbonate = 0.3 (mmol/l) x base deficit x wt (kg) Sodium Bicarbonate 8.4% has 1mmol bicarbonate in 1 ml How many mls of Sodium Bicarbonate will you give? 6

7 Calculation of drugs per weight The dosage of some drugs is prescribed according to body weight. Example: A child weighs 5 kg and is prescribed 50mgs Ampicillin per kg of body weight You have 250 mg/5mls How many mls are required? Answer: Step I Weight x prescribed dose 5 kg x 50 mg/kg =250mg Step 2 What you want / what you've got X volume 250 mg / 250 mg X 5mls = 5mls Question 6: A child of 7 kg is prescribed 100 mgs Ampicillin per kg of body weight. You have in stock 250 mgs diluted in 5 mls of water. a) How much is required for one dose in milligrams? b) What volume do you require? 7

8 Morphine questions Morphine = mcglkglhr Midazolam = mcg/kg/hr Use 0.9% NaCl or 5% dextrose for dilution Amount of morphine added to make infusion is 0.5mg/kg of child s weight in 50mls 0.9% NaCl or 5% Dextrose. Amount of midazolam added to make infusion is 3 mg/kg of child s weight in 50mls 0.9% NaCl or 5% Dextrose. Question 7: The child weighs 10 kg. You need to run the infusion so the child receives 20mcg (micro grams) per kg per hour of morphine. How would you calculate the rate in ml per hour that this is to run at? Question 8: The child weighs 10 kg. You need to run the infusion so the child receives 300mcg (micro grams) per kg per hour of midazolam. How would you calculate the rate in ml per hour that this is to run at? Question 9: You have another child who weighs 20 kg. You have an infusion that contains 20 mg (milligrams) in 50 mls of morphine. You need to run the infusion at 30 mcg per kg per hour. What rate will you need to run the infusion at in mls per hour? 8

9 Question 10: You have another child who weighs 50 kg. You have an infusion that contains 50 mg (milligrams) in 50 mls. You need to run the infusion at 40 mcg per kg per hour. What rate will you need to run the infusion at in mls per hour? 9

10 Section 2 The following clinical scenarios are all re1ated to intravenous therapy and require you to demonstrate your problem solving skills Scenario 1 Whilst on duty, you are caring for a 6 year old in sickle cell crisis with a continuous morphine infusion to manage his acute pain. You check that the pump is infusing while doing his observations and all seems well. Three hours later, the pump alarms and you note that the syringe is nearly empty. While checking the infusion you notice that the infusion pump is set a 2 mls/hr. The prescription chart requests 60 mg in 50 mls 0.9% Saline at 1ml/hr, while the previous prescription requested 30 mg in 50 mls 0.9% Saline at 2 ml/hr. What steps do you take in this situation? What do you think may have happened in this situation? What steps can be taken to ensure such errors are not made? 10

11 Scenario 2 You are the only IV giver on your shift. The ward is busy and the junior staff nurse informs you that her child has IV. antibiotics due and could you administer them for her. When you arrive at her bed space, you find that the IV's have been drawn up and left for you with the patient's drug chart and empty ampoules. She tells you that she has already drawn them up to save you time. What do you do? Please justify your answer using the Code of Professional Conduct and Trust Policy as your evidence. 11

12 Scenario 3 You have administered 250 mg of Vancomycin to a patient in 50 mls of Normal Saline over one hour. Part way through the infusion the child's mother calls you as her child has a florid rash, is breathless and complains of a bad headache. What actions might you take? What may have happened? Prior to administrating this drug, what information did you need? Where could you find this information? What actions might you take in the future to help prevent this from occurring? 12

13 Scenario 4 Shortly before the end of your shift, the doctor asks you to 'put up' a 500ml bag of Normal Saline that needs 30 mmols of Potassium added to it. The child has a peripheral cannula in situ. Based on this information would you be prepared to administer the prescription? Why? What is the maximum rate at which potassium can be safely administered via a peripheral line? What is the normal potassium level in the blood? What are three main hazards of l.v. Potassium administration? What actions on your part would ensure that this child has the best possible care in this instance? 13

14 Scenario 5 A 6-month-old infant has been admitted with diarrhea and vomiting. An intravenous infusion has been sited in the dorsal aspect of the right hand and is infusing 0.9% Saline with added Potassium Chloride. The infant is distressed and crying. You notice that the lv bandage is wet and the infant's arm appears red and swollen to the elbow. What action do you take? What factors could have contributed to this occurring? What would you do in future to prevent this scenario? 14