Planning should include an estimate of the number of patients who will require transport to another facility as well as the necessary staff, equipment and supplies to accompany them.

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The decision to evacuate an entire building after a major event involves complex logistical issues, especially if vertical transportation is lost. The length of time it takes to totally evacuate a building depends on not only the time it takes to transport the affected patients to the on-site staging area, but also the transportation resources to get those affected patients to the receiving facility.

In December 2013, the Centers for Medicare and Medicaid Services (CMS) published their proposed rule on emergency preparedness requirements. Tucked away are references to two Agency for Healthcare Research and Quality (AHRQ) documents. One is called the Hospital Assessment and Recovery Guide and the other is the Hospital Evacuation Decision Guide.

The following discussion will look into the evacuation guide to better understand the implications of decisions made during the early stages of a disaster. A perfect evacuation plan would exhaust the most critical resources when the last patient leaves the building.

Systemic guidance

The purpose of the Hospital Evacuation Decision Guide is to provide the hospital with organized and systemic guidance on how to consider the factors that drive the decision to order an evacuation. It is also meant to assist in identifying special situations that may exist in the facility or geographic area that could affect the decision to evacuate.

The evacuation guide uses two tools to use as part of the planning process:

  • A pre-disaster assessment of critical infrastructure focuses on vulnerabilities that may affect the likelihood that a hospital may need to evacuate prior to or in the aftermath of a disaster.
  • The evacuation time self-assessment provides a framework for estimating the time required to safely evacuate all patients. Perhaps the most important tool in the guide is the method to estimate how long it might take to evacuate a hospital.

Ultimately, these tools are used to plan for two kinds of evacuations:

  • Pre-event evacuation. When an evacuation is undertaken in advance of an impending disaster. This happens frequently in advance of hurricanes.
  • Post-event evacuation. When an evacuation is carried out after a disaster has caused that the hospital is no longer able to “defend in place.”

After an evacuation is ordered, incident command must then decide the order in which the patients are evacuated.

The pre-disaster self-assessment consists of an assessment of critical infrastructure and an estimate of evacuation time. A closer look at these two studies provides important guidance.

Critical infrastructure assessment

A key consideration when issuing a pre-event evacuation order is to assess vulnerabilities and determine the potential impact of the impending event on the hospital and the local community. Generally, water and power are the most critical pieces of infrastructure.

Table 4 of the Hospital Evacuation Decision Guide divides the infrastructure assessment into eight sections: municipal water, steam, electricity, natural gas, boilers and chillers, powered life-support equipment, information technology and communications, and security.

The focus on critical infrastructure, specifically HVAC, water and electricity, is appropriate because these systems are critical for hospital operation. The loss of these systems for any extended period usually triggers a consideration of evacuation.

Incident command should know how long the facility can shelter-in-place if critical systems are damaged.

For example, the guide asks, how long could a hospital maintain safe operating temperatures without municipal water during summer months? Cooling towers consume a great deal of water to create the chilled water that air conditions a facility. If the municipal water supply were lost, air conditioning systems could soon begin to fail leading to untenable conditions in the hospital.

Possible implications of a sudden loss of these eight critical infrastructures include:

  • Municipal water. Loss of municipal supply can compromise the fire suppression system, heating, cooling and sanitation. This in is addition to the hydration needs of the patients, visitors and staff.
  • Steam. Loss of steam may not only impair sterilization and high-level disinfection capacity but also lead to loss of building heating, humidification and domestic hot water. References suggest that loss of steam production during winter conditions could lead to evacuation of hospitals located in colder climates within one to two days.
  • Natural gas. For hospitals using natural gas for heating and/or hot water, damage to gas mains lasting more than one to two days (especially during winter months) could lead to an evacuation. Loss of natural gas can be mitigated by dual-fuel boilers. However, if the secondary fuel supply (oil, for instance) is also used by emergency generators and operating concurrently, the time to exhaust the secondary fuel supply could be significantly reduced. The hospital’s self-assessment should recognize the reliance on natural gas and if there is more than one gas line serving the facility.
  • Electricity. The availability of electrical service plays a significant role in evacuation decisions. Prolonged electrical power loss leads to possible impact to patient care, as some patients depend on life-support equipment driven by electricity. Ventilator battery packs are known to last two to three hours. Additionally, the loss of electrical services could impact the HVAC systems. Without its HVAC systems, hospitals lose ambient control of the environment, which is essential for general health and safety along with medical technologies. The number of hours that a hospital can function without municipal electrical power or adequate fuel for backup generators is a critical factor in evacuation decisions.
  • Boilers/chillers. Redundancy of boilers and chillers is rare for most hospitals. The loss of these systems may necessitate an evacuation, depending on weather conditions. The pre-disaster self-assessment should recognize vulnerabilities due to loss of boilers and chillers, irrespective of the loss of electricity, water or steam.
  • Powered life-support equipment. As stated earlier, life-support equipment such as ventilators may have batteries that last two to three hours. Patients dependent on such equipment may need to be evacuated more quickly than others. The self-assessment should review the inventory of powered life-support equipment in use on the average day, how many pieces of equipment have battery backup and how many hours these batteries are expected to last. Proper management of resources and assets should identify stocks of medical equipment not in service when disaster occurs. If spare devices are fully charged, they can be exchanged with equipment when batteries are depleted.
  • Health information technology. Loss of information technology and telecommunications will reduce a hospital’s ability to deliver care efficiently. In other cases, service delivery may be interrupted altogether because automated systems may not be quickly replaced by manual systems. A hospital must consider how it would provide patient care services without an electronic medical record and the impact this will have on its ability to provide such services.
  • Telecommunications. This consideration focuses on the extent that computers and essential data are backed up or managed off-site, whether redundant hardware and software exists, whether paper or manual systems can be quickly reintroduced, and whether the hospital has backup telephonic communication that does not rely on the local providers.
  • Security. Additional security is needed to keep unauthorized personnel out of the facility, protect transport vehicles and maintain order within the hospital. If the hospital is fully evacuated, security will still be needed to protect the premises.

Estimating evacuation time

As part of pre-disaster planning, a decision team should estimate the time required to safely evacuate all patients. But should a team be focused at the beginning of every event to determine when the point arrives to make the decision to stay or leave? The answer depends on how well the critical infrastructure is analyzed and understood. 

There are two components of evacuation time planning to be evaluated. 

The first is the time to empty the building. This is the time it would take for all patients to be moved from their location in the hospital to a staging area from which they can be transported to another hospital or receiving facility. The staging area may need to accommodate patients in beds or other emergency transport equipment, their associated medical equipment and medications. The staging area could become clogged very quickly without proper planning.

Movement of the patients from their rooms to the staging area and beyond depends on factors internal to the facility such as whether elevators are operational, whether staff have participated in evacuation drills and how quickly staff can arrive to assist with the evacuation.

If elevators are not operational, another factor to consider is whether the staff involved with the evacuation can deal with the physical demands of moving patients down flights of stairs with equipment, medications and paper records, and then climbing back up those stairs to do it over again.

The second component of evacuation is the time to transport patients from the staging area to the receiving facility. These factors are generally external to the hospital. These factors include transportation resources and availability, road conditions and the locations of the receiving facilities. If helicopters can be used for the transfer, do they have alternate landing locations?

Approaches to estimating. The AHRQ lists the following possible approaches to estimating the time to evacuate patients:

  • Experience of other hospitals. Although not recommended by AHRQ, data from other hospitals and published after-action reports can be a source of information to estimate evacuation time under specific scenarios.
  • Exercises. Results of evacuation tabletop exercises confirmed by data from drills can inform evacuation time. For example, a hospital may drill how a patient may be evacuated down a stairwell if elevators are not available. The drill can help determine the size of the team required to transport the patient from their room to the staging area and the time it takes. These data can be extrapolated to the census.
  • Computer models. Simulations and other computer models are available for planners.
  • Experience. This involves estimating the number of round trips required for each vehicle participating in the evacuation and the average round trip cycle time from staging area to receiving facility.

Factors influencing time. Whichever method is chosen, a number of factors can influence evacuation time, including:

  • Number and acuity mix of the patient population. The total number of patients who will need assistance to evacuate will often be fewer than the total patient census. Some patients may be medically stable and will be able to self-evacuate or evacuate with family members. Other patients will require special equipment and handling if they are to survive the evacuation.
  • Available staff. Staff will not only be needed to move patients from their rooms to the staging area, but others will be needed to accompany the patients to the receiving facility. Depending on the type of disaster, there will likely be staff shortages. Attrition rates of staff available to respond should be estimated. Also, staffing on nights and weekends is lower, making the ability to evacuate a hospital more difficult. As stated earlier, consideration must be given to physical demands of the staff assigned to evacuate patients without the use of elevators.
  • Available egress routes within the hospital. During an urgent evacuation, egress from the hospital may be severely constrained. Stairwells or exits may be dark, obscured by smoke or unavailable due to fire. Clearly understand where all exit stairs are located and which can be used as a backup if other exit stairs are not available for use. Consideration may also be given to assigning a stairwell that can be used by staff to return to areas being evacuated without encountering traffic moving toward the bottom.
  • Patient transport requirements. The planning should include an estimate of the number of patients who will require transport to another facility. Transportation resources not only include the number of vehicles available, but also the required staff, equipment and supplies necessary to accompany patients to the receiving facility.
  • Available transport resources. The number of transport vehicles available is a determinant of how long it might take to move all patients to the receiving sites. For example, if 100 patients require evacuation and there are five transport vehicles available, each vehicle will be required to make 20 round trips. Logistical issues now would come into play such as travel time and fuel availability.
  • Entry and egress points. A hospital evacuation requires road access to ramp-equipped hospital exits. With constraints, an orderly evacuation might be estimated to take days. Furthermore, poor communication may lead to numerous vehicles waiting for patients to transport or patients waiting at hospital staging areas for vehicles.
  • Road and traffic conditions and locations of receiving facilities. In a disaster that causes widespread evacuation of health care facilities, transport destinations may include other geographic areas. Traffic-choked highways and lack of refueling assets can also slow the evacuation by preventing vehicles from cycling back for repeated evacuation trips. Hospitals may consider if alternate landing sites for helicopters can be accommodated in other areas.

How to prepare?

It is hoped that no hospital will ever need to fully evacuate a building after power and vertical transportation infrastructures are compromised. But if it’s possible, it will happen. 

How can an organization prepare for such an event? The first step is to understand the resources it would take to transport a critically ill patient from the highest floor of the building to a grade level staging point. How many people are needed, and how much time will it take to complete the task?

With this knowledge, a health care organization could extrapolate the amount of personnel and transportation required to get the patient to the receiving facility and then to recycle the process. 

Tom Kinman, PE, CHFM, CHSP, is a retired VP of facilities management at Cincinnati Children’s, and he consults for Joint Commission Resources. His email is