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Nursing Mathematics: What Skills Do Nursing Students Bring to Drug Calculations? Roslyn Gillies Learning Skills Unit Student Support Services University of Western Sydney LSU 2006 1 A bit about where I come from … LSU 2006 2 LSU 2006 3 what I do … LSU 2006 4 and where I do it … LSU 2006 5 UWS – Sydney, NSW, Australia LSU 2006 6 A bit about UWS … Six campuses covering entire west of Sydney 36 000 students – 32 000 undergrads Larger campuses: Parramatta & Penrith Smaller: Hawkesbury & Blacktown Motto: ‘Bringing knowledge to life’ Emphasis on practical courses, providing educational opportunities for students in the region LSU 2006 7 How does Nursing Mathematics fit with Ethnomathematics? Several definitions of ethnomathematics … … the study of mathematics which takes into consideration the culture in which mathematics arises (University of Idaho website) … the mathematical practices of identifiable cultural groups (Ubiratan D’Ambrosio – first used in late 1960s) LSU 2006 8 Human activities which require some form of mathematics Architecture - construction Weaving – textiles and baskets Sewing – turning cloth/skins into clothing or shoes that fit Agriculture – calendars to mark seasons, planning for quantity and storage, layout of gardens and fields Kinship relations Ornamentation – tilings and beadwork Spiritual and religious practices (uidaho.edu website) … and Nursing – dosage calculations! LSU 2006 9 Mathematical skills nurses require Computational skills fractions, decimals, percentages, ratio, measurement, conversion between units Conceptual Skills- ability to: set up the problem for calculation apply an appropriate solution method LSU 2006 10 The culture and tradition of teaching drug calculation Early 1980s – Florence Nightingale’s hospital-trained apprentice system was replaced by higher education training Occurred in countries such as: UK Canada USA Australia New Zealand LSU 2006 11 Impacts of this change ‘Big bang’ curriculum revolution rather than incremental change Emphasis on intellectual and higherlevel thinking skills, problem solving Mastery of basic principles rather than facts Less time in clinical practice situation LSU 2006 12 Other factors affecting drug calculation instruction Increasing student diversity Multidisciplinary nature of nursing maths (maths applied in a nursing context) Medication calculation frequently a stressful task performed on the ward No clear policy on whose responsibility it is to develop and maintain nurses’ drug calculation competence Little agreement on teaching methods LSU 2006 13 Other factors (cont.) Assumption that maths skills taught in the abstract will be successfully transferred to nursing context Some nursing educators admit to poor maths skills and difficulty in teaching drug calculations Limited opportunities for students to practice drug calculation skills Reliance on formula methods that do not always result in students retaining skills LSU 2006 14 The tradition of using formula methods for drug calculation Widespread use of formula methods Examples of formulae taught: Volume required to deliver a given mass: (Gatford & Phillips, 2002, p. 44) LSU 2006 15 Another formula taught … Drip rate for Intravenous Infusion: (Hext & Mayner, 2003, p. 80) LSU 2006 16 Why are formulae taught? “… to bypass the need to appropriate or understand any mathematical structure and to impose consistency on what were seen to be dangerous variations in strategy” (Hoyles et al., 2001, p. 13) LSU 2006 17 The dilemma – Advantages of formula methods Standardised methods: one-sizefits-all Easy to apply Plug in the numbers and turn the handle to get the answer Don’t need to think too much LSU 2006 18 Disadvantages of formula methods Little use of students’ existing problemsolving skills Encourage belief that drug calculation is a separate branch of mathematics Do little to encourage students to think through the problem and understand the calculation method Do little to encourage estimation and checking strategies to ensure calculated dosage is reasonable LSU 2006 19 What the literature says … Some students find formulae difficult to use correctly Formulae may be a cause of conceptual errors Formula methods are frequently ineffective and result in: poor skill development poor retention of skills LSU 2006 20 What the literature says … (cont.) In workplace situations nurses make little use of formulae learnt Instead, nurses use a variety of correct proportional reasoning methods that preserve the meaning of the problem situation (Hoyles et al., 2001) LSU 2006 21 The study Subjects: 35 recently enrolled first year B Nursing students at UTS Instruments: Test – 10 calculations (see OHT) set in everyday contexts designed to parallel typical drug calculation problems Questionnaire – demographic data LSU 2006 22 Problem types simulated in test Calculate: Number of tablets to deliver a given mass Volume required to administer a given mass, either: orally by injection Intravenous medications: drip rate (drops per minute) time to run the infusion LSU 2006 23 Some of the questions … PRT item 4. A 12.5 kilogram bag of flour lasts a cook 5 days. How many days will 45 kilograms of flour last the cook? Parallel DCT item 4. On hand is Benadryl 12.5 mg per 5 mL. How many millilitres will you give if Benadryl 45 mg is ordered? LSU 2006 24 PRT item 5. An automatic drip feeder installed in an aviary is to deliver 600 millilitres of water to the birds every 10 hours. If the feeder delivers 60 drops per millilitre, how many drops are delivered each minute? Parallel DCT item 5. An intravenous drip is to deliver 600 mL of normal saline over 10 hours. If the giving set delivers 60 drops per mL, what is the drip rate in drops per minute? LSU 2006 25 PRT item 7. A dripping kitchen tap loses 1 litre of water over 8 hours. It is established that 15 drops of water is equivalent to 1 millilitre. Calculate in drops per minute the rate at which the tap is losing water. Parallel DCT item 7. A patient is ordered 1 litre of normal saline over 8 hours. The intravenous giving set delivers 15 drops per mL. Calculate the drip rate in drops per minute? LSU 2006 26 PRT item 10. A car travelling on a country road is losing water from the radiator at the rate of 25 drops per minute. The driver uses his last 600 millilitres of water to top up the radiator. How long will it take for this amount to leak out if 20 drops of water is equivalent to 1 millilitre? Parallel DCT item 10. An intravenous giving set is delivering an infusion at the rate of 25 drops per minute. The patient is to have 600 mL of Hartmann’s. How long will the infusion take if the giving set delivers 20 drops per mL?? LSU 2006 27 Research questions Before being exposed to drug calculation instruction of special formulae: How well do students perform on tasks similar to drug calculations? How successful are students in applying appropriate problem-solving methods to set up the problem for calculation? What are the ‘native’ methods used by students to solve such problems? LSU 2006 28 Scoring – two methods Method 1 – right/wrong – test mark out of 10 Method 2 – score/3 for each item – test mark out of 30 1 mark: some progress 2 marks: correct method used 3 marks correct method and correct answer LSU 2006 29 Student profile Female: 94% Ages: 17-48 mean 25.6 (sd 7.7) Mathematics backgrounds: NSW HSC-level mathematics: 78% Year 10 (junior high) maths or less: 20% Maths studied after leaving school: 9% NESB Language background: 12% LSU 2006 30 Mean score Method 1 (score/10) Mean score: 3.65 (sd: 2.25) Method 2 (score/30) Mean score: 15.17 (sd: 7.57) LSU 2006 31 Pass requirement: 80% correct Method 1: (score ≥ 8/10) Pass: 11% of students Fail: 89% Method 2: (score ≥ 24/30) Pass: 17% Fail: 83% LSU 2006 32 Pass requirement: 100% correct Methods 1 & 2: (Score: 10/10 or 30/30) Pass: 0% Fail: 100% LSU 2006 33 Deficits in students’ skills Inability to set up problem for calculation (Blais & Bath, 1992; Rutherford, 1996) Computational errors (Gillies, 1994; Gillham & Chu, 1995) Errors in metric conversions (Rodger & Jones, 2000) LSU 2006 34 Some of the problem-solving methods students used Division operations Unitary method and adaptations Fraction of a quantity Proportion (formal set up) Ratio Proportional reasoning Rewrite rate in equivalent form LSU 2006 35 No. of students nts No of items where correct method applied 7 6 5 4 3 2 1 0 0 1 2 3 4 5 6 7 8 9 10 Number of items where correct method applied LSU 2006 36 Ability to apply correct method On average, another 1.4 Qs per student where correct method used For 26% of students, a further 3-4 Qs where correct method used For 40% of students, at least 2 additional Qs where correct method used LSU 2006 37 Items of particular interest Those with greatest difference between % of students obtaining correct answer and % using correct method–Items 4, 5, 7, 10 ie many more students can apply a correct method than can get the correct answer These include all three IV infusion problems – traditionally most difficult Qs For these items, high incidence of causes, other than conceptual difficulties, that prevent success viz computational difficulties LSU 2006 38 Item 5 – Melika’s working LSU 2006 39 Item 5 – Nicola’s working LSU 2006 40 Item 5 - Summary Key to success: Being able to convert: ml to drops hours to minutes Being able to express stated ‘drip rate’ in appropriate equivalent forms LSU 2006 41 Item 7 – Cate’s working LSU 2006 42 Item 7 – Alison’s working LSU 2006 43 Item 7 – Melika’s working LSU 2006 44 Item 7 – Karen’s working LSU 2006 45 Item 7 - Summary Simplest process: Change ml to drops early Leave conversion of hours to mins until the end (otherwise large numbers result) Also valuable was the ability to express division in fraction form and cancel down (avoids long division) LSU 2006 46 Item 10 – Karen’s working LSU 2006 47 Item 10 – Melika’s working LSU 2006 48 Item 10 - Summary Both students used same method Both had difficulty in arithmetic processes: Karen gained a zero is division (2-step process) Melika lost a zero in same division (long division) LSU 2006 49 What analysis of students’ working suggests Difficulties with IV problems are not always because of conceptual difficulties Many students able to set up problem and apply appropriate method Having applied an appropriate method, poor conceptual skills may prevent progress to correct answer LSU 2006 50 Conclusions On average, students able to apply correct method to half of the 10 items – even before any drug calculation instruction Many students fairly well equipped to deal with even the most difficult drug calculation problems (IV problems) Methods students use involve multiple steps that preserve meaning of problem (Hoyles et al., 2001) When correct method applied, incorrect answers caused by poor arithmetic skills (Gillham & Chu, 1995; Cartwright, 1996) LSU 2006 51 Recommendations for nursing educators Need to reassess the appropriateness of focus on teacher-taught formulae for drug calculations Avoid ‘killing off’ students’ existing problem-solving skills Avoid fostering the belief that drug calculation is a separate and unrelated branch of maths Encourage students who prefer to use ‘native’ methods and assist them in refining those methods LSU 2006 52 Recommendations cont. If formulae taught, ensure development of understanding: Unravel the multiple steps embodied in the formula Stress these steps may be performed separately Encourage students to think flexibly and apply a range of problem-solving methods – leads to mathematically powerful students (Schoenfeld, 1992) Further research needed in areas such as: the conceptual skills of nursing students students’ ‘native’ problem-solving methods and how they might apply them to drug calculation LSU 2006 53