The Louisiana Department of Health (LDH) provides medical, preventative, and rehabilitative services for all the state’s 4.6 million citizens. Due to the significant impact of hurricanes on the region every year, the LDH must maintain plans for the emergency evacuation of entire hospitals based in the most populated portion of the state, to alternative, out-of-state facilities. However, this is a complex undertaking that requires the cooperation - and funding - of several government agencies. LDH worked with Palisade’s Custom Development team to build a risk analysis model with a custom interface, based in @RISK. The customized model incorporates the expanding number of uncertain and unknown variables, and subsequently enables the state to get the federal support it needs in the event of an emergency of this size.
Louisiana is a "Wet Lab" for Emergency Preparedness
Due in part to the significant impact of hurricane season on the Gulf Coast of the U.S., Louisiana is considered a “wet lab” for emergency preparedness. As part of its annual preparations, the State creates and maintains plans that involve the full coastal evacuation of entire hospitals and nursing homes in Southeastern Louisiana - which is highly populated, has a significant medical infrastructure and is particularly vulnerable to hurricanes. As Louisiana doesn’t have enough capacity for an emergency surge of patients in the northern part of the state, most evacuees need to be transported to the neighboring states of Arkansas, Oklahoma, and Tennessee. The only way for the State to accomplish an evacuation of this size is by partnering with the National Disaster Medical System (NDMS) and the U.S. Military Transportation Command (US TRANSCOM), which can provide the necessary aircraft, crews and support personnel to get patients safely to the receiving hospitals. “Ground transportation isn’t an option as there aren’t enough ambulances to move such a high number of patients such a long distance before a hurricane makes landfall,” explained Henry Yennie, Emergency Preparedness Program Monitor for the Louisiana Department of Health (LDH). “The only reasonable way to evacuate patients to out-of-state hospitals is by air, and the only viable source for aircraft that can carry large numbers of patients is the military and national guard.”
Every year, the LDH provides its federal partners with a Health and Medical Response Report that outlines the State’s Emergency Support Needs for the next hurricane season. The plan outlines the needs of Louisiana’s “at risk” patient population in the event of a large, coastal hurricane strike, and provides the government organizations with a logical, analytical and reasonable explanation for the resource requests. Palisade’s @RISK software plays a critical part in both estimating the need for and justifying these resources. “It helps us make the case for our plan and how it is constructed, in case someone questions our data or methodology,” said Yennie.
Modeling Resource Requirements for Emergency Hospital Evacuations
Each federal partner wants to know how many patients will need to be moved out of the State, before they agree to providing the requested resources. As it’s not possible to provide an accurate number prior to an emergency, the LDH needs a way to provide a realistic range of numbers, including the supporting probabilities. In addition, they need a solution that supports the State’s commitment to minimizing the unnecessary movement of critically ill and electrically dependent patients. As the unpredictability of a storm’s landfall makes it extremely difficult to accurately predict if, and when these fragile patients should be moved, they need a model that provides them with a blend of different EVAC (evacuation) and SiP (shelter in place) scenarios. “Palisade built a sophisticated model for us that allows us to take the configuration data and construct a model, quickly and easily,” said Yennie. “@RISK is a really valuable tool that lets us perform up to 10 different scenarios based on patient numbers and other data, plus it has an interface that makes it ‘idiot proof’ for us.”
Working with Palisade Custom Development to Create a User-Friendly Model
Due to the complexity of the situation, LDH worked with Palisade’s Custom Development team to create the model. “Using spreadsheets only, it was very easy to make mistakes that would have cascading error effects in the model. We needed the VBA UIs in some areas to prevent this type of error, and make configuring the model for specific situations more intuitive,” explained Yennie. “The Palisade team built several VBA screens that allowed us to easily configure the model without making errors that impacted other parts of the model. It eliminated the ‘rabbit hole’ work required to find out where the original error occurred, for example ‘turning off’ an airport or taking certain aircraft out of stock.”
“Palisade was extremely responsive, completed the work quickly, and unlike a lot of developers, they provided user-friendly documentation that makes end-user training much easier. We still refer to it prior to every event to ensure our entire team is on the same page, and it has proven extremely helpful in explaining with the model is doing to senior leadership,” added Yennie.
@RISK Simulates the Evacuation of Multiple Patient Populations
To create a new model, the LDH begins by identifying four different types of patients who might need to be evacuated: psychiatric patients, burn patients, pediatric/neonates/high-risk mothers, and general medical / surgical and Intensive Care Unit (ICU) patients. They consider four possible destinations for these patients: in-state hospitals with pediatric and obstetrics capabilities, in-state hospitals with available psychiatric beds, in-state hospitals with available burn beds, and out-of-state hospitals through the National Disaster Medical System (NDMS) network. They also consider all possible methods of patient transportation including bus, paratransit, ground and air ambulances, as well as military air assets such as C-130 heavy-lift transport aircraft. “In addition to the types of planes we have access to and the number of patients who can be carried on each plane, we have to identify the cycle time between flights, how many turns a single plane can make, and the impact if a plane breaks down,” added Yennie. “All of these are variables that impact our final results and recommendations.”
The LDH uses Bernoulli distributions, which are special two-point distributions used to determine the probability of two possible outcomes, to model whether or not a flight will occur. They use three-point Pert distributions to model minimum, maximum and mode (most common) cycle times and patient estimates. Palisade’s @RISK also allows them to create high-resolution graphics to present the output distributions from their simulations in a way that easily illustrates the risks. LDH uses tornado graphs, which help them identify which variables are having the biggest impact on each scenario, and what they can do to mitigate the risks.
@RISK Used for Planning Before and During an Actual Hurricane
The LDH uses @RISK for their annual planning activities, as well as during an actual hurricane. According to Yennie, “@RISK gives us benchmarks we can measure against actual patient movements, then lets us know the probabilities of success. By providing us with this estimate of success throughout the process, we’re able to figure out what we can do to fix it right away.”
In the past two years, LDH has used @RISK to justify the need for significant changes to the evacuation plan, largely due to the problem of critical care patients. TRANSCOM medical guidelines define critical care patients more expansively than hospitals. As a result, the capability for transporting these types of patients was shifted to the national ambulance provider, AMR, contracted through FEMA. AMR is now providing the air assets to move critical care patients. Palisade’s @RISK software was used to not only provide a valid basis for the Louisiana request, but also informed how many flights would be necessary to meet the expected demand. Yennie said, “We were able to accurately model the correct demand for the critical care patients and match that to the capabilities of the FEMA contractor. The result was a realization by FEMA that an activation of that contract for the zone containing Louisiana would require surplus capabilities available from other zones.”
“I’ve used other simulation software over the years and none has come close to the usability of @RISK. It makes it really easy for a person who doesn’t have a PhD in statistics to build an accurate model of a real-world situation that has an impact,” concluded Yennie.