“Cleanliness is next to godliness.” – John Wesley
A bad joke about the brand of povidone iodine scrub that I like to use got me thinking on how we prevent infections during surgery. Covid, of course, brought out an astronomical increase in the net worth of hand sanitizer barons and for the first time people outside of healthcare were washing their hands and disinfecting them to the point of getting skin reactions. That then rocketed the net worth of dermatologists who could do teleconsults far easier than say, neurosurgeons. But as always I digress. The history of surgical asepsis, which is the fancy way of saying “please don’t touch me or my instruments once we have this gown on”, is fraught with errors in judgement, the famed ego of surgeons, some reasonable observational science and perhaps a significant smattering of posthumous “I told you so”.
Way back in the day there are records of ancient civilizations using honey and wine as antiseptics. And then a host of other substances were thrown on to wounds based on social, cultural and religious practices of the time. Some good but some most certainly dubious in their efficacy. The middle ages and “renaissance” saw a precipitous drop in the concepts of cleanliness and sterility especially with regard to care of patients.
We then had Ignaz Semmelweis, who in the mid-19th century, noted a stark difference in infection rates between two maternity wards—one staffed by doctors and the other by midwives. The high mortality rate among mothers in the doctor-attended ward, he realised, was due to the lack of handwashing. The midwives he found were washing their hands with chlorinated lime solution, which while a skin care nightmare, definitely reduced infections and mortality. His ideas faced resistance and were largely ignored by the medical community of his time. And we will see instances like these time and again in the history of medicine.
The discovery that bacteria and other “small animalcules” were the likely causes of infection led to what is now called the germ theory of disease. Louis Pasteur (from whose name we have pasteurization of milk and other foods) and Robert Koch (who lent his name to tuberculosis, which is often referred to as Koch’s disease) discovered that pus from wounds were teeming with little microorganisms and these were the likely cause of infection. This discovery was a pivotal moment in modern medicine and to date the most readily curable conditions in medicine are bacterial infections. The 19th and 20th centuries have seen tremendous improvements in understanding the need of asepsis, sterility and overall cleanliness. Joseph Lister was responsible for spraying the operating suites, tables and instruments with carbolic acid. Which while being an excellent disinfectant and antiseptic was harsh and toxic to human skin.
At this point is probably good to dwell on the difference between disinfectants and antiseptics. Antiseptics are used to clean living tissue and may either kill or stop the growth of bacteria. Disinfectants are used on non living surfaces and kill bacteria. Think Dettol vs Harpic. That should clear things up.
Currently we do have a few set protocols and ways of ensuring sterility during surgery. Typically most Operating rooms are cleaned and fumigated with fairly harsh chemicals once a day and while the cleaning and wiping of all surfaces happen between surgeries, fumigation is only repeated if a particular surgery is on a contaminated surgical field or infected patient. These may include prior infected wounds that need cleaning and dressing, abscess that may need drainage, gangrenous limbs, planned or unplanned opening of the colon during abdominal surgeries, to name a few. The next is sterilization of instruments. The commonest way of doing this for hardier metal instruments is steam sterilization. Basically a large pressure cooker. Instruments are washed, dried and packed into sets and placed in the “autoclave” at a fixed temperature and pressure for a predetermined time. Usually every set has an indicator strip placed that changes colour if the sterilizing conditions are correct and is a sign that all is clean. Smaller flash sterilizers are used for a quicker turnaround in emergency situations.
Cold sterilization is used for delicate instruments, or non metallic instruments. This may be done by exposing them to ethylene oxide. The instruments are packed in plastic sleeves and sealed and placed in to the ETO sterilizer. The gas is able to penetrate the plastic and sterilize the instrument. Similarly delicate instruments may also be sterilized by exposure to hydrogen peroxide plasma , ultraviolet radiations or even ozone.
Another significant change that has happened in surgical care in india over the past 20 years is the increasing use of single use disposables. While gloves, syringes, needles, intravenous tubing, saline bags, blades have long been single use and disposable; surgical gowns, drapes that we use to keep the surgical field sterile, drapes around intraoperative x-rays, microscopes etc are also now made of composite liquid resistant fabrics and come pre-sterilized.
There is possibly a massive ecological impact of this but to be fair at this point I would carry my own bag to the grocery store but will use a single use product for my patients.