History of Sterilization

To understand the foundations of medical device sterilization, you have to understand the time before a sterile medical field. Before modern germ theory infiltrated the wider medical community, circa 1850, was far from the sanitary practices we know today. The norm was unhygienic and lacked the awareness of germs. Medical dogma appropriated by the community was disease was caused by miasma—amorphous emanations from rotting flesh or vegetation. They were also confident in imbalances in bodily humors (blood, phlegm, yellow bile, and black bile).

Naturally doctors and other medical professionals of the time were reusing dirty tools, dressed in their daywear, and were not washing their hands. Unfortunately, there was an ignorance of microbes: Germ theory didn’t gain traction until the late 19th century. Obviously, sterility wasn't even a consideration.

A Hungarian obstetrician called Ignaz Philipp Semmelweis, made a surprising discovery: Washing with chlorine prevented new mothers from dying of fatal infections after giving birth. The fatality rate of this phenomenon was approximately 18%. Due to deadly germ contamination from performing autopsies and subsequently delivering children; Semmelweis recognized there to be lethal overlap between these two activities. Women would die of sepsis within the first six weeks of childbirth–the puerperal period.

After implementing handwashing following an autopsy, results followed almost immediately. Within a few short months the death of new mothers dropped astonishingly from ~18% to 1–2%. The awareness of germs and true cause of disease was still yet to be discovered. Although, he did address a link that he called "cadaverous particles".

Unfortunately, his ideas failed to catch on at the time, and Semmelweis was eventually committed to a mental asylum where he received brutal treatment. He died there.

Modernization

After his death, the Great Sanitary Awakening occurred toward the tail end of the 19th century. The wider medical community finally started implementing handwashing and other sanitary practices. After the 1860’s we got the introduction of antiseptics and the eventual integration of tool sterilization.

Enter steam sterilization or autoclaving and its humble beginnings. By the turn of the 20th, we’d effectively repurposed the 1600’s pressure cooker into a promising streamlined sterilization tool for the medical field.

Obviously, the unsanitary beginnings are relevant to where we are in modern times. We’ve made unimaginable leaps in technology since the 18th century. Revolutions in the medical industry call for innovations in engineering to make surgeries more successful, less invasive, and lower the mortality margin as much as possible.

Without the breakthroughs we’ve discussed here today, there isn’t a future to speak of.

Unapproved Types of Sterilization

Previously, we have covered a short list of sterilization methods. Today we’re going to expand on the list, just to illustrate the breadth of options that exist. While there are a lot of methods that are approved by the FDA, there are also methods that aren’t.

We can’t suggest outfitting any particular device to them, should you seek approval and ultimately get denied. If the method you’ve sought to use isn’t recognized by the FDA, you run the risk of potentially damaging your device with the methods that are approved.

Formaldehyde Gas Sterilization

A time consuming low-temperature chemical sterilization method. While an effective method of sterilization and approval from foreign governing bodies, the FDA doesn’t recognize this method. This decision is due to carcinogenic properties, toxic residues, and inconsistent sterilization performance. The range of the devices this can be utilized for is relatively small, some being: endoscopes, plastic components, rubber materials, and certain electronics.

Radiant Heat Sterilization

Items are placed in a dry heat oven. Sub-optimal processes may use temperatures below 160°C or insufficient time. This method lacks FDA approval because of sub-optimal dry heat because they fail to consistently meet safety, efficacy, and reliability standards and insufficient microbial killing capabilities. This method also has a relatively low repertoire of materials that it works on: Glassware (e.g., flasks, syringes, petri dishes) and metal instruments (especially surgical-grade stainless steel). It doesn’t work well with plastic components, unfortunately, they melt or degrade during the process. This is also the case for rubber and electronic materials.

Stay tuned!

Thanks for reading, and this was a first for a two-parter. We’ll have the subsequent edition out soon!

Make sure to subscribe to the newsletter to get notified when we get another one up!