The Missing Link in Patient Flow Efforts
Updated: Mar 21
Roger Resar MD., Kevin Nolan Mstat, MA., Deb Kaczynski MS
The often overlooked, yet the most effective component of managing patient flow is a hospital’s ability to match unscheduled demand with fixed capacity in a dynamic state. What specific proactive process does your hospital undertake beyond just using technology and analytics to generate demand and capacity numbers at any given time?
Patient Flow is comprised of two simple components: demand and capacity. Therefore, in order to improve flow, hospitals have traditionally focused on either making an adjustment to demand or capacity. This simplistic approach was a natural conduit to a myriad of projects to adjust either the demand or capacity. Projects like discharge lounges, shortening discharge times, improving turn around times for bed cleaning or changing inpatient operative procedures to outpatient settings, to name a few. Our experience and data over the last two decades show that such projects have had little impact on hospital-wide patient flow on a consistent basis.
What is needed is a set of processes that would allow an understanding of demand and capacity of hospital flow in a real dynamic state. This process is called real time demand capacity management (RTDC) and was developed in partnership with the Institute for Healthcare Improvement (IHI). In this article, we provide an overview of the concepts that form the foundations of RTDC:
Concept #1: Queuing Theory is the art and science of matching relatively fixed capacity to unscheduled demand. One does not need to be proficient at queuing theory to understand the impact small changes will have in a hospital at peak times. When utilization is high, small increases in available capacity or small reductions in demand will result in large reductions in waits. RTDC facilitates those small changes as the match between capacity and demand is predicted and plans are developed to impact the mismatches. (Hall. R. Queuing Methods. Prentice Hall, Englewood Cliffs, NJ, 1991.),
Concept #2: In gas dynamics, small fluctuations in the flow of gas through a pipe can cause a clog which propagates back from the location of the initial clog. This phenomenon is referred to as a compression wave. L.C. Davis at the University of Michigan has studied traffic jams and has reached similar conclusions. 75% of all traffic jams are caused not by a large event such as an accident or road construction but rather random small events such as bright sun or an accident in the opposite lane causing drivers to slow down in a random fashion resulting in a compression wave caused by. The key is to stop the compression wave from forming. In traffic flow, Professor Davis concluded the answer is adaptive cruise control. RTDC applies this concept to patient flow within hospitals by focusing on 25 percent of the day.
Concept #3: Moving from a culture of managing patient flow in days to managing patient flow in days and in hours allows for the full expression of the queuing and compression wave science. Managing length of stay (LOS) has traditionally been a focal point of patient initiatives since most hospital reimbursements are based on LOS (DRGs). Hospitals in general have responded to the connection between financial reimbursement and LOS with successful efforts at LOS reduction (through multidisciplinary rounds for example to keep patients on a discharge plan) but still have overcrowding and delays in their ED and PACU. These delays are the result in mismatches in demand and capacity at specific times during the day. To alleviate these hospital delays the focus is on managing in hours rather than just