Introduction
The
interval starts with the patient’s arrival in the Emergency Department and ends
when a catheter guide wire crosses the culprit lesion in the Cardiac Cath lab.
In everyday language, this just means that a balloon is inflated inside one of
the heart’s primary blood vessels to allow unimpeded blood flow through the
heart. The clock starts ticking either as a walk-in to the Emergency Department
or in the field where a patient is being attended to by medical personnel. This
metric is enormously important to patients simply because the longer this
procedure is delayed, the more damage occurs to the heart muscle due to a lack
of oxygen to the heart muscle. It’s damaged because the cause of this problem
is typically due to a blockage within the heart that prevents oxygen from being
supplied to the heart, and without proper amounts of oxygen, muscle damage
results. The inflated balloon “unclogs” the blood vessel. Graphically, door to
balloon might look like Figure 1.
I
started this event with a training session for the team members focusing on how
to use an integrated Theory of Constraints, Lean Six Sigma improvement
methodology. I have seen a lot of Process Value Stream Analyses (PVSAs) where
waste is identified throughout the process, and then the team works to either
reduce it or eliminate all of it. It
has been my experience that when attempting to reduce the time it takes to
process something through a process, such as this one, by attacking the entire
process for waste reduction, teams frequently miss the opportunity to reduce
the cycle time much more quickly than they otherwise could have. This is where
the Theory of Constraints (TOC) and its Five Focusing Steps offers a much
quicker solution to this type of project. Just to review, TOC’s Five Focusing
Steps, first introduced by the late Dr. Eli Goldratt. These five steps are:
- Identify the system constraint—In a physical process with numerous processing steps, the constraint is the step with the smallest amount of capacity. Or another way of stating this is the step with the longest processing time.
- Decide how to exploit the system
constraint—Once the constraint has been identified, this step
instructs you to focus your efforts on it and use improvement tools of Lean and
Six Sigma to reduce waste and variation, but focus your efforts mostly on the
constraint. This does not mean that you can ignore non-constraints, but your
primary focus should be on the constraint.
- Subordinate everything else to the
constraint—In layman’s terms this simply means don’t
over-produce on non-constraints, and never let the constraint be starved. In a
process like the Door to Balloon time, it would make no sense to push patients
into this process, since they would be forced to wait excessively. But of
course, the hospital cannot predict when patients with heart attacks will show
up needing medical attention. But by constantly trying to reduce the
constraint’s time, the wait time should be continuously reduced.
- If necessary, elevate the constraint—This
simply means that if you have done everything you can to increase the capacity
of the constraint in Step 2, and it’s still not enough to satisfy the demand
placed on it, then you might have to spend money by hiring additional people,
purchasing additional equipment, etc. That is, anything that would reduce the
time in the constraint.
- Return to Step 1, but don’t let
inertia create a new constraint—Once the constraint’s
required capacity has been achieved, the system constraint could move to a new
location within the process. When this happens, it is necessary to move your
improvement efforts to the new constraint if further improvement is needed.
What is thing about inertia? What Goldratt meant by that was to make sure
things you have put in place to break the original constraint (e.g. procedures,
policies, etc.) are not limiting the throughput of the process. If necessary,
you may need to remove them.
In
my next post, I will continue with this case study.