Professor Skinner Exam study

Introduction

This transcript focuses on calculations for IV drug administration and related math concepts essential for nursing.

Drug Preparation and Calculation

The discussion begins by distinguishing between milliliters (ml) and grams, for instance, noting that $3.5 \text{ ml}$ of a solution corresponds to $1 \text{ gram}$. To calculate the total volume, this $3.5 \text{ ml}$ is added to $100 \text{ ml}$ of saline, resulting in a total volume of $103.5 \text{ ml}$. It is crucial to always consider the final volume if the solution is reconstituted further.

Setting IV Pumps

To set IV pumps, the flow rate is calculated using the formula: $\text{Flow rate} = \frac{\text{Volume}}{\text{Time}}$. In this context, the volume is $103.5 \text{ ml}$ and the time is typically one hour ($1 \text{ hr}$), leading to a flow rate of $103.5 \text{ ml/hour}$.

Converting ml to Drops

For converting milliliters to drops, the drop factor of a given IV set is utilized, such as $20 \text{ drops/ml}$. The total drops per hour are calculated by multiplying the flow rate by the drop factor: $\text{Total drops/hour} = 103.5 \text{ ml/hour} \times 20 \text{ drops/ml} = 2070 \text{ drops/hour}$. To convert this to drops per minute, divide by 60: $\frac{2070}{60} = 34.5 \text{ drops/minute}$.

Problem Solving Steps for Dosage Calculation

Problem-solving for dosage calculation involves several steps. First, weight conversion may be required when units are specified (e.g., mg/kg), using an example of a $70 \text{ kg}$ patient. Second, dosage calculation often involves cross-multiplying, setup as: $\frac{\text{Desired dosage}}{\text{Supply}} \times \text{Quantity}$, with a specific focus on conversion factors like grams to milligrams. Lastly, dimensional analysis is critical to ensure all units (mg, grams, mls, etc.) cancel out correctly, and calculations must be thoroughly checked to prevent errors.

Example Calculations

An example of Vancomycin administration involves an order of $1 \text{ gram}$ every $12 \text{ hours}$, supplied at $5 \text{ grams}$ per vial. This would be reconstituted with $10 \text{ ml}$ and further diluted in $250 \text{ ml}$, with the pump rate calculated based on the total mixed fluids.

Drip Rate Calculations

Drip rate calculations use the formula: $\text{Drip rate} = \frac{\text{Volume}}{\text{Time}} \times \text{Drop Factor}$. This is applied for a given drip factor, such as $10 \text{ drops/ml}$, and for total milliliters per hour.

Calculation Techniques

When performing calculations, dimensional analysis is a reliable technique. Always set known variables (desired dosage, supply, conversions) clearly and cross out units as needed to ensure clarity about what needs to be solved.

Clinical Considerations

Managing IV flows and calculations requires careful consideration of medication interactions and patient weight. Common pitfalls in error-prone areas like dosage and reconstitution must be avoided. Adhering to hospital protocols and verifying calculations are paramount for patient safety.

Fluid Input and Output Knowledge

Fluid input includes anything added to the body, while output encompasses any bodily ejection, including fluids. Types of fluids counted in intake include liquid foods such as broth, Jell-O, and ice, noting that ice counts as half its volume. Guidelines are discussed regarding what counts towards intake concerning solids like soup and cereal.

Summary and Study Techniques

Regular practice of calculations in a structured manner will build familiarity. Dimensional analysis is presented as the most reliable method for tackling complex dosage calculations.