OSMT (Ontario Society of Medical Technologists) Practice Exam

Which type of sterilization does the autoclave method utilize?

1. Wet heat

2. Dry heat

3. Chemical

4. Physical

The correct answer is: Wet heat

The autoclave method utilizes wet heat sterilization, which is characterized by the use of steam under pressure to achieve high temperatures that effectively kill microorganisms. This process is particularly effective because steam can penetrate fabrics and other materials more efficiently than dry heat, allowing for a thorough sterilization of surgical instruments, media, and certain types of equipment. During autoclaving, the pressurized steam achieves temperatures of approximately 121°C (250°F) for a set period, typically 15 to 30 minutes, depending on the material being sterilized. The moist environment created by the steam aids in denaturing proteins within the microorganisms, leading to their destruction. An important factor to note is that this method differs from dry heat sterilization, which uses hot air that can reach higher temperatures but requires longer exposure times and is less effective in penetrating certain types of materials. Chemical sterilization involves the use of various vaporized or liquid chemical agents, while physical sterilization techniques may include methods like radiation. Each of these alternatives has its specific applications and limitations, but for the efficient and broad-spectrum bacterial destruction and sterilization of instruments, autoclaving through wet heat remains the gold standard in many healthcare and laboratory settings.