Monday, October 20, 2014

Handling Ebola Patients: An Engineering Problem

Two nurses who treated the late Ebola-virus victim Thomas Eric Duncan have been diagnosed with Ebola virus as well.  They treated him at the Texas Health Presbyterian Center hospital in Dallas, where he died on October 8 after traveling there from Liberia, where he acquired the virus.  Despite apparently following the protocols recommended by the U. S. Center for Disease Control (CDC) for dealing with patients with Ebola, nurses Nina Pham and Amber Joy Vinson are now being treated for the disease as well.  Their chances are grim:  the death rate from the virus can be as high as 50%. 

Besides all that, one could be excused from believing that nothing else is going on in the U. S. right now except the Ebola virus, at least judging from the media coverage in Texas.  If there is a futures market in Clorox, now's your chance.

We are used to thinking of technology only in terms of hardware, or maybe hardware and software.  But engineering designs can center around people and their behavior too.  The elaborate protocols and procedures that integrated-circuit manufacturers follow are just as essential to making their chips as the silicon is.  A roomful of advanced medical equipment is just so much scrap metal without the people and plans and procedures that can use them effectively.  And just as machines can be well or poorly designed, so can protocols.

Let's look at two protocols.  One is posted on the CDC website under the title "Infection Prevention and Control Recommendations for Hospitalized Patients with Known or Suspected Ebola Virus Disease in U.S. Hospitals."  That's pretty clear.  What do they say about personal protective equipment for the nurses and other personnel who care for Ebola patients?  It's pretty simple:  a face mask, eye protection (goggles or a face shield), gloves, and a gown ("fluid resistant or impermeable").  I don't know about you, but if I was within a few feet of a potential source of fluid that had a good chance of giving me a deadly illness, I would want to be covered by something more substantial than a "fluid-resistant" gown.

Now, let's consider another set of protocols.  In an editorial in the Oct. 16 Austin American-Statesman, critical care physician Bryan Fisk recalls the protocol he used when he was in charge of a Biosafety Level 4 Patient Isolation Suite at Ft. Detrick, Maryland.  This was a military facility designed to handle patients with diseases as dangerous as Ebola.  What kind of personal protective equipment did they use at this facility?  "[F]ully encapsulated positive-pressure protective suits with a tethered air supply."  In other words, a diving suit without the water.  Not only were they trained to do all sorts of procedures—intubation, catheterization—while wearing these undoubtedly cumbersome outfits.  Once they left the isolation unit, they underwent a complete chemical scrubdown while still wearing the suits, with the aid of other technicians.  And as long as they were treating the patient and for the length of the incubation period afterwards, they were confined to on-site quarters and not allowed to leave until there was no chance that they had acquired the virus.

There are reportedly about four of these types of isolation units in the U. S.  Understandably, they are more expensive than the standard emergency-room or intensive-care isolation units maintained by even the best public hospitals.  But in view of the fact that the CDC protocols, even if followed, fall far short of what the U. S. military does when dealing with Ebola-type situations, it's hard to resist the temptation to repeat an old consulting-engineer saying. 

The story goes that one day a consulting engineer gets a call from a factory manager where things are going haywire.  He flies out to the site, walks around a half hour or so, and then motions for the manager to come into a private office with him.  He sits down and says to the manager, "Your system is perfectly designed to give you the results you're getting."  In other words, you should not expect a badly designed protocol to deliver good results.

Fortunately, nurse Nina Pham has been transferred to a National Institutes of Allergy and Infectious Diseases isolation unit in Bethesda, Maryland.  I was unable to find any information on the protocols for protecting healthcare workers in that unit, but one hopes that it is better than the CDC's bare minimum. 

The perception of competence can be as important as actual competence.  Doctors and medical-care workers are some of the most trusted professionals in society, and when a scary thing like an Ebola case happens, the presumption is that those in charge will follow the best practices available to ensure that the disease doesn't spread.  With the failure of Texas Health Presbyterian Center to use adequate protocols, whether due to thinking that the CDC knew what it was talking about or otherwise, that trust has been severely damaged, and the word "panic" has started to show up in news items on the virus.  Professionals can be excessively reluctant to second-guess other professionals, but in this case it looks like it would have been better for someone in authority to order the Texas hospital to send Duncan to a military or equivalent-quality isolation unit the instant it became clear he was infected.  He might have died anyway, but we would have avoided any possibility that Ebola carriers were running around in public and flying in planes, which is the situation we face now.

Realistically, the risk of catching Ebola for the average person in the U. S. is virtually no higher than it was a month ago, which was approximately zero.  But already, serious damage has been done to the medical profession's reputation, and it will be some time before the fears of Ebola subside.  We can get there sooner if every organization involved with Ebola fully acknowledges the seriousness of the problem and spends the money and resources necessary to deal with it safely—or else admits they can't do it and defers to an organization that can. 

Sources:  Dr. Bryan Fisk's article "We need to send Ebola patients to U. S. disease-isolation facilities," appeared in the Oct. 16 edition of the Austin American-Statesman, p. A10.  The CDC's recommended protocol for Ebola appears at, and as of this writing was last updated Oct. 6.  The Dallas Morning News has a helpful timeline on Ebola in the U. S. at

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