Reducing risk from heater-cooler devices

We now know that heater-cooler devices (HCDs) are capable of producing bio-aerosols in the operating room (OR), and that these bio-aerosols can cause devastating infections. Obviously these devices must be re-engineered to eliminate bio-aerosol production, or replaced with other approaches to regulate the temperature of cardiopulmonary bypass machines and cardioplegia solutions. Until then, temporizing measures to eliminate risk from these faulty devices are needed. 

We’ve already discussed our approach to removal of HCDs from the OR, and the approach they’ve used in Zurich (encasing the HCD in a stainless steel housing and venting the exhaust outside of the OR). At SHEA and ECCMID I saw interesting descriptions of two other approaches to separate the HCD exhaust from OR air.

First, at SHEA a group from Boston Children’s Hospital presented a “Wall Water System” that takes advantage of ready availability of hot and cold water supplies near to the OR, combined with a medical grade mixing valve to carefully regulate temperature. This allowed them to provide heating and cooling without the need for an HCD. An ECCMID attendee noted that this approach has also been initiated at one or more hospitals in Europe. See the image below for the full poster (sorry for image quality, it’s my own iPhone pic!). 

At ECCMID, John Conly from Calgary presented their experience with contaminated HCDs, and their approach to placement of the HCD within an enclosure that included the OR exhaust vent that was drawing the HCD exhaust out of the OR. Their poster is below. 

I’m most intrigued by the first approach: using existing hot and cold water supplies, along with precision mixing valves, to eliminate the need for a free-standing unit in the OR that exists solely to regulate the temperature of a water reservoir.

Resistance is on the March

This past weekend, we joined the March for Science in St Louis – and on social media got to see other marches from all over the world.  The numbers in DC, Chicago, Boston and other big cities were impressive, but equally, if not more so, were the turnouts in smaller cities and towns across the US, and the pictures sent in from Guam, Arctic research stations, and Wake Atoll in the Pacific.  Science for the purposes of these marches was defined as broadly as it could be, as it should be.  Paleontologists, geologists, physicists and chemists, engineers and math teachers, sociologists and climate scientists were all there – and many more whose signs didn’t proclaim their area.  One sign read “Without Science, It’s Just Fiction” and there were Dr Who and Star Trek fans (and actors) there to bear witness. Of course, I particularly noticed the medical sciences and the signs calling out the impact of vaccines and other medical advances on human health. I also learned a new and creative use for old posters! While I didn’t see any signs specifically referencing infection prevention or hospital epidemiology, I liked the sign reading “Microbiologists Support All Cultures” and was struck by the one that said “Even the Bacteria Are Resisting…”

            That last sign of course turns the concept of resistance in a different direction, but that kind of resistance is also “on the march” (stick with me here).  A recent research letter in EID by Perez and colleagues used VHA microbiology data to map the spread of carbapenem-resistance (CR) in Klebsiella pneumoniae  and Enterobacter cloacae complex across the US from 2006 – 2015.  In an excellent example of the value of VHA data, the maps show what the authors call a ‘second epidemic’ of CR – Enterobacter.  Unlike CR-Klebsiella which started in the northeast and spread west and south,  CR-Enterobacter was detected in both northeast and almost simultaneously in west coast VHA facilities.  From there, it spread to meet in the middle of the south, by 2015 sparing only a few states. The percentage of E cloacae isolates with carbapenem resistance rose steadily over the study period.  The figures are sobering.

My cousin asked me, gently, whether I thought the science marches “changed any minds”, or were just another way of  “preaching to the choir”.  My answer was no, I don't think minds were changed by the march.  I’m not sure “changing minds” was even the goal.  I told him I hoped the marches drew attention to how large the field of “science” is, and how many supporters it has.  I hoped it drew that attention from legislators and politicians contemplating budget priorities and funding cuts.  I hoped the marches pointed out how many people would be watching those decisions carefully and asking for explanations by phone call, postcard and at town hall meetings.  Because the march of both kinds of resistance continues – and how we respond has serious consequences. 

SHEA2017 Storify

Mike Edmond, Silvia Munoz Price, and Gonzalo Bearman at the SHEA2017 C. difficile screening debate.

If you missed last week's SHEA Meeting in St. Louis, check out Steve Pergam's Storify below. He's a Twitter master who summarizes the meeting in 506 Tweets.