Chapter 1 - Introduction

Abstract

This chapter focuses on types of medical devices, material used in them, and criteria for selecting various medical devices. Medical devices can be classified into two major categories—disposables and nondisposables. Examples of nondisposable devices include machines and instruments, diagnostic equipment, surgical and dental instruments, prostheses, and implants. Examples of disposable devices include bandages, gloves, blood bags, colostomy bags, catheters, syringes, IV kits, and tubing. Materials used in nondisposable applications must typically meet long-term durability and stringent physical and mechanical properties. Materials used in machines and diagnostic equipment do not necessarily need to be sterilized or meet specific chemical resistance or biocompatibility requirements. Examples of diagnostic and surgical equipment are MRI machines, electrocautery devices, and electrocardiogram (ECG) monitors. Implants on the other hand must meet strict biocompatibility, biodurability, and sterilization requirements to be safe and effective in the body. It is important to know the dimensions, size, and weight requirements for the part or product. Consideration must also be given to the loads, stresses, and impact that the product might see during its use. With the increased use of electronics, electrical conductivity or insulation must be addressed. Some materials might need to dissipate accumulated static charge, whereas other materials might need electrical insulation properties. Electrical properties to consider are conductivity, dielectric strength, volume or surface resistivity, and comparative tracking index (CTI).