Drug Calculations for Nurses

A Step-by-Step Approach

Robert Lapham

• Publisher: Routledge
• Year: 2021
• ISBN:
  9781000389913
• Edition: 5
• Topic: Medicine
• Subtopic: Nursing Skills

This new edition of Drug Calculations for Nurses teaches healthcare professionals how to perform drug calculations with confidence and competence. It provides step-by-step guidance to carry out accurate drug calculations, with units and drug strengths clearly explained.

This bestselling pocket-size book begins with the basic mathematical skills required to perform calculations, including tips on estimating answers. It then covers drug strengths and concentrations, dosage calculations, IV infusion therapies, and pharmacodynamics and pharmacokinetics. Separate chapters focus on children, adults and the elderly, addressing specific challenges encountered in these populations, with new content on pregnancy, and renal and liver function. Helpful worked examples, key points, and objectives are included in every chapter, and this new edition includes more calculations for prescribing and patient-focused scenarios. The companion website, www.drugcalcsnurses.co.uk, provides a comprehensive test bank, with a pre-test and revision test to identify strengths and weaknesses, along with additional practice questions for readers to test themselves on.

Designed for students and practitioners in nursing, midwifery and allied health, this textbook enables readers to improve their numeracy skills for clinical practice and develop their understanding of the broader context for these calculations.

PART I

This part of the book contains topics that cover the basics of mathematics, particularly multiplication and division.

Following on from this, there is a section on the order of operations (BODMAS or BEDMAS). This describes what to do when you have more than one operation, such as 3 + 3 × 2.

These concepts are then applied to various relationships with numbers: how to work with Fractions, Decimals and Percentages.

Chapters in this section cover:

• Basics

1
INTRODUCTION

HOW TO USE THIS BOOK

This book is designed to be used for self-study.

To attain maximum benefit from the book, start at the beginning and work through one chapter at a time as subsequent chapters increase in difficulty. For each chapter attempted, you should understand it a fully and can answer the problems confidently before moving on to the next chapter.

Alternatively, if you wish to quickly skip through any chapter, you can refer to the Key Points found at the beginning of each chapter.

Readers of this book are able to access additional online content at www.drugcalcsnurses.co.uk. The online content consists of a Pre-Test, Revision Test and additional questions. To obtain the maximum benefit from this book, it is a good idea to attempt the pre-test before you start working through the book. The pre-test will enable you assess your current ability in carrying out drug calculations so that you can determine which areas you should concentrate on. Additional questions are available for more practice. After completing the book, repeat the Revision test and compare the two scores to see if you have made any improvement.

BEFORE WE START

Drug calculation questions are a major concern for most healthcare professionals, including nurses and those teaching them. There have been numerous articles highlighting the poor performance of various healthcare professionals.

The vast majority of calculations are likely to be relatively straightforward and it is probably infrequent that you will need to perform any complex calculation. But it is obvious that people are struggling with basic calculations.

It is difficult to explain as to why people find maths difficult, but the best way to overcome this is to try and make maths easy to understand by going back to first principles. The aim is not to demean or offend anyone, but to remind and explain the basics. Maths is just another language that tells us how we measure and estimate and these are the two key words.

It is vital however; that any person performing calculations using any method, formula, or calculator can understand and explain how the final dose is actually arrived at through the calculation.

NUMERACY

Apart from drug calculations, numeracy is used for a range of health-care activities, such as measuring height and body weight, drug administration and managerial tasks such as budgeting (Hutton 2009) – see table for a list of situations where numeracy is used (Young et al., 2012).

Why do nurses regularly perform badly in numeracy tests? McMullan et al. (2010) provided some suggestions: individuals who are anxious about performing numeracy may be drawn to people-oriented and caring careers such as those in healthcare. They also suggested an over reliance on calculators and no practice in mental arithmetic in secondary schools are contributing factors. ‘Maths anxiety’ has sometimes been implicated – Williams and Davis (2016) state that students who believe they are not able to master the concepts of...