Saturday, February 11, 2006

Take a deep breath. Hold it.

They say generals are always fighting the last war. It seems that our disaster planners have the same problem. They are planning for "events" that happen in one or a few places where they can truck in critical supplies from "the outside." But in a pandemic there is no outside, and some people are beginning to realize the implications.

People like critical care physicians. Even without an epidemic they are feeling the pinch in a health care system that lost 38,000 inpatient beds in the four years 1996 - 2000. It's not just regular hospital beds. Intensive Care Unit (ICU) beds shrank 20% in the same period. Even before you get to a bed, 91% of its Emergency Department (ED) Directors reported overcrowding in a recent survey.

Last month Hicks and O'Laughlin published a chilling preview of what is in store entitled “Concept of Operations for Triage of Mechanical Ventilation in an Epidemic” in the journal Academic Emergency Medicine. Title translation: what do do when we run out of ventilators during a flu epidemic.

The authors are emergency physicians in Hennepin Country, Minnesota (the Minneapolis metro area), population 2.6 million. They asked what would havppen if just 10% of the population were affected by flu and with only 20% of those affected too sick to care for themselves. That would be roughly 52,000 people. If only one in five of those required hospitalization, that would mean an extra 10,400 patients. They estimated Hennepin Country had an "excess" (surge) capacity of 2500 to 3500 beds. In the SARS epidemic in Toronto, mean hosptial stay was 10.5 days. In Singapore it was 18 days. This is far longer than current hospital stays and would further exacerbate the shortage of critical care beds. That's bad. But there's worse.

If a bird flu epidemic were anything like 1918, many of the seriously ill would require mechanical ventilation (i.e., machines to breathe for them), perhaps for considerable periods of time. The authors report that in a bioterrorism drill in their regional compact of 27 hospitals (with 480 ICU beds), they quickly found
a rapid and critical shortfall in ventilators when challenged with just more than 400 pneumonic plague cases. Despite a surge capacity of 2500 to 3500 beds in the area, there were only 16 ventilators available from vendors in our regional system.

Obviously we are now in the dreaded area of triage, that is, rationing critical medical resources. With admirable foresight, the Hennepin County planners began to think through what they would need to do. They convened a group that devised a tiered approach, i.e., one that would start with the least stringent rationing but ramped up as shortages required. The first tier to be excluded were those where ventilators would be with held or withdrawn when they became generally unresponsive to intensive care or had otherwise extremely poor prognoses (e.g., failure of four or more organ systems as evidenced by specific clinical criteria). If shortages exceeded what these restrictions made available, a new set of exclusions for mechanical ventilation would come online, involving patients with pre-existing system compromise or failure (e.g., patients with congestive heart failure with specific clinical signs or AIDS patients at a stage of disease making them susceptible to opportunistic infections). If this were still insufficient, a next group might consist of flu patients whose risk factors were more unfavorable(e.g., age specific survival data) or who had additional disease categories than above (e.g., advanced cancer patients).

Unpalatble? Yes. But necessary. The basic idea is to have a scaleable, explicit and agreed upon ahead of time scheme for rationing a scarce clinical resource. It is important to think this through in advance, with open discussion in all sectors of society, rather than depend on a haphazard and ad hoc rationing forced upon us by swiftly moving and chaotic events.

That is a recipe for injustice and inefficiency, as the powerful get what little is available and the rest get nothing.