Bottlenecks

Once you've identified the time each patient spends at a certain step, you can identify which takes the longest.

NOW, you have identified the bottleneck.

Everything is dependent upon this bottleneck.  Recall the rate limiting step (RLS) in chemistry.  This step is typically a catalyst or rare substrate.  It's the process that S - L - O - W - S  everything else down.  In the ED, this may be: time to get a lab report, a 5150 bed, or the the on-call dialysis nurse.

Use a multi-perspective approach by including RNs, Techs, ICU docs, etc. to reduce the time it takes in the slowest step.  This can be challenging, but will reap huge rewards.

Lather, rinse, & repeat.

What are the important things to measure for ED flow improvement?

There are many metrics in the ED, ranging from patient satisfaction to % of Medicaid patients.   To improve patient flow and identify bottlenecks, there are 10 steps and times that should be measured:

1. Door to Triage

2. Triage to MD (assuming MD is in triage)

3. Bed to RN

4. Bed to MD

5. MD to Decision (DC vs. ADMIT)

   6) Imaging order to read

   7) Lab order to results

   8) Recheck of patient

9) DC to actually being out of ED

10) ADMIT to floor

If you add the total time of each of these steps, this equals total Length of Stay in ED (LOS).

Based upon the review of the time needed for each of step, an ED director can determine which areas need more effort and time to reduce the time in ED.  This is crucial because patient satisfaction is linked to the overall time in ED. 

Little's Law Applied to the ER

Little's Law is a fundamental equation in operations. It's like F = m*a to physics and CO=HR*SV to critical care.

Applying it in the ED, Little's law states:

Number of patients in ED = Arrival rate of patients/hr * Avg length of stay in ED/Pt

Two of these numbers are readily available. Number of pts in ED and the arrival rate.

For example, lets assume that the ED bed capacity is 50 beds and normally has 40 beds occupied at a given time. The arrival rate on an average day is 10 pts/hr. What is the average length of stay in the ED?

Avg length of stay = # of pts in ED / arrival rate

= 40 pts / (10pts/hr)

= 4 hrs

Based upon this, we can figure out average LOS in ED and work on factors to decrease total ED length of stay for patients.

* More on Little's Law (pdf)