Implications of Hospital Evacuation After the Northridge Earthquake

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Implications of Hospital Evacuation After
theNorthridge Earthquake

• Carl H. Schultz, MD
• Professor of Emergency Medicine
• UCI Medical Center

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Introduction

• Hospitals throughout the world are at high risk
  for serious damage from earthquakes.
• Yet virtually nothing is known about evacuation
  of in-patients from such facilities after a
  seismic event.
• The vast majority of disaster medical literature
  addresses hospital evacuation due to hurricanes,
  floods, fires, and hazmat spills.

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Introduction

• Problematic factors for hospital evacuation after
  earthquakes
• Absence of warning
• Determining structural and functional status
• Loss of elevators, power, communication
• Damage to neighboring hospitals
• Evacuation of patients from damaged structures

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Introduction

• The Northridge earthquake provided the
  opportunity to study the evacuation of
  in-patients from several hospitals damaged
  simultaneously by a seismic event.
• This is the largest project to date evaluating
  off-site evacuation of in-patients from
  earthquake damaged hospitals.
• Funded by a grant from the National Science
  Foundation

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Objectives

• Examine how decisions were made regarding triage
  and the partial or complete evacuation of the
  hospitals
• Identify the techniques used to move patients
  within and between effected facilities
• Describe the emergency management strategies
  employed during the evacuation

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Methods

• Observational retrospective investigation
• All acute care hospitals in Los Angeles County
  which evacuated in-patients off-site as a result
  of the Northridge earthquake
• Identified through records from L.A. County
  Department of Health Services and the State of
  Californias Office of Statewide Health Planning
  and Development

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Methods

• Standardized survey instrument
• 58 questions
• Reviewed by professional survey writer
• Various formats
• Scaled scoring (rate 1-5)
• Open ended. Participants questionnaires not show
  stimuli for answers.
• Yes/No

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Methods

• Hospital administration recruited at least one
  member from the following groups to participate
• Physicians
• Nurses
• Administration
• Mechanical/facilities management

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Methods

• Survey mailed to each hospital and distributed to
  individuals for review
• Investigators then visited each hospital and
  interviewed the participants in person using the
  questionnaire
• All participants interviewed together
• Process required 2 hours
• Investigators recorded all responses by
  participants

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Methods

• All interviews conducted by the same person
• ? score not needed
• Some interviews conducted by phone
• Involved one person
• Approved by Institutional Review Board at
  Harbor-UCLA Medical Center

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Results Hospital Demographics

• 166 medical facilities inspected for earthquake
  damage in Los Angeles
• 18 acute care hospitals
• ?20 (91 hospitals total)
• 25 Intermediate Care Facilities
• 123 Nursing homes
• 14 of 18 reported some form of patient evacuation
  - horizontal or vertical (?15)

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Results - Hospital Demographics

• 8 hospitals (?9) reported off-site evacuations
• 1 pediatric hospital 1 psychiatric hospital
• 2 general hosp. (private) 2 trauma centers
• 1 general hosp. (county) 1 veterens hospital

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Results - Hospital Demographics

• Year built 6 before 1973 2 after 1973
• No. of stories 3(2), 5(1), 6(3), 8(2)
• No. of patients 74-334
• No. of stairwells 5-15
• No. of elevators 3-15
• Types of specialized units MICU, CCU, NICU, PICU

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Results - Evacuation Decision
6 hospitals evacuated in first 24 hours
(immediate group)

• Initial evacuation decision
• Horizontal vertical evacuation decisions made
  by house supervisor or spontaneously
• Off-site evacuation decision made by Chief
  Hospital Administrator
• Damage assessment information used by all
  institutions in decision-making process

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Results - Evacuation Decision
Immediate Group

• Both hospitals built after 1973 in this group
• 4 of the 6 hospitals were completely evacuated,
  including the 2 post 1973 institutions
• 2 hospitals condemned (pre 1973)

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Results Evacuation Decision Reasons for
Off-site Evacuation in Immediate Group
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Results - Evacuation Decision
2 hospitals evacuated after first 72 hours
(delayed group)

• Initial evacuation decision
• Horizontal vertical evacuation decisions made
  by house supervisor or spontaneously
• Initial structure assessment negative
• Structural engineers change assessment in 3 and
  14 days respectively
• Off-site evacuation decision made by Chief
  Hospital Administrator
• Both hospitals completely evacuated and condemned

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Results - Evacuation Decision
Delayed Group

• Both hospitals built before 1973
• Possible reasons for change in status
• Damage always present, just missed
• Damage progressed with aftershocks
• Damage always present but difference of opinion
  on its severity
• Politics
• Note Patients from 2 institutions in immediate
  group evacuated to hospital in delayed group, and
  then forced to evacuate again

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Results - Evacuation Decision
Triage

• Immediate group
• 4 of 6 felt no urgency to evacuate
• Used standard triage protocols (sickest first)
• 2 felt evacuation urgent - 1 used scoop and run
  (no triage protocol), 1 moved healthiest patients
  first
• Delayed group - standard triage

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Results - Evacuation Techniques

• Patients moved using backboards, walking,
  wheelchairs, blankets, sheets. Stairs only
• Did not use special equipment such as stair
  chairs, slides, etc. Felt unnecessary
• Personnel shortages
• 3 reported staff reductions of 20-50
• Would not leave families, roads out
• Staff remained on duty to compensate
• Skill mix suffered

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Results - Evacuation Techniques

• All hospitals performed horizontal vertical
  evacuations
• Damaged floors to undamaged floors
• From one side of hospital to another
• To other hospital locations
• ED, parking lot, cafeteria, SNF
• 4 of 6 hospitals sent children home
• Parents came in spontaneously or were called

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Results - Evacuation Management

• Immediate group - selection of off-site hospitals
  for evacuated patients
• 1 used MAC (Medical Alert Center) exclusively
  (central control).
• 4 used local network (independent)
• 1 used both methods
• No difference in evacuation time
• Delayed group - selection of off-site hospitals
  for evacuated patients
• 1 used MAC and 1 used local network

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Results Evacuation Management

• Transportation
• 6 of 8 hospitals used the MAC to obtain
  transportation vehicles
• 1 used local news agency (helicopter)
• 1 hospital (delayed group) used local EMS network
  (fire departments)
• Patient tracking
• No hospital had problems transferring medications
  records with patients

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Results Evacuation Management

• No problems getting other hospitals to accept
  patients (no financial triage)
• Personnel sent with NICU, ICU, and psychiatric
  patients.
• Psych patients remained under control of
  transferring hospital
• No associated morbidity or mortality
• 3 deaths not related to quake or evacuation

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Results Evacuation Management

• Communications - not completely fail
• Pay phones worked
• Cell phones worked sporadically
• Some land lines worked, then failed as network
  jammed with calls
• Ham radios, ambulance radios, hand-held radios
• All evacuations relied on functioning
  communications

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Results Evacuation Management
Distance from Epicenter (miles) Modified Mercalli Intensities (MMI) Peak Ground Acceleration ( Gravity) Condemned
STUDY HOSPITALS
Hospital 1 0.8 VIII 79.6 No
Hospital 2 4.0 IX 89.4 No
Hospital 3 4.0 VIII 93.4 Yes
Hospital 4 6.7 VIII 74.3 No
Hospital 5 9.5 VIII 81.4 No
Hospital 6 12.9 VIII 59.0 Yes
Hospital 7 21.5 VII 46.1 Yes
Hospital 8 21.8 VII 46.1 Yes
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Results Evacuation Management
Distance from Epicenter (miles) Modified Mercalli Intensities (MMI) Peak Ground Acceleration ( Gravity) Condemned
CONTROL HOSPITALS
Hospital A 2.8 VIII 49.3 No
Hospital B 8.4 VIII 51.3 No
Hospital C 12.7 VII 34.3 No
Hospital D 13.0 VIII 60 No
Hospital E 15.3 VI 37.5 No
Hospital F 16.7 lt VI 19.9 No
Hospital G 17.3 VII 27.5 No
Hospital H 22.8 VI 13 No
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Hospitals without structural damage
Epicenter
Hospitals scheduled for demolition
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Results Evacuation Management
Epicenter distance

• Hospital closure from structural damage had no
  statistically significant association with
  distance from the epicenter in the near field.
• The mean epicenter-to-hospital distance
• Condemned facilities 15.1 miles (95 CI 1.6 to
  28.5)
• Non-condemned facilities is 10.8 miles (95 CI
  6.6 to 15.0)
• The difference in the means is -4.2 (95 CI
  -13.0 to 4.5)

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Results Evacuation Management
Peak Ground Acceleration

• Hospital evacuation had a statistically
  significant association with peak ground
  acceleration in the near field.
• Study hospital mean PGA 0.71g (95 CI 0.56 to
  0.87)
• Control hospital mean PGA 0.39g (95 CI 0.27 to
  0.52)
• The difference in means is 0.32g (95 CI 0.14 to
  0.50) and is statistically significant.

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Conclusion

• Moderate earthquakes cause damage to hospitals
  that is severe enough to require evacuation
• Post 1973 building code standards provide
  insufficient protection
• Serious structural damage may not be evident
  immediately
• Evacuating patients to hospitals within the
  disaster zone may be unwise

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Conclusion

• Patients can be evacuated safely from
  earthquake-damaged hospitals using available
  staff and equipment
• Special slides, chairs, etc are not necessary
• Distance from the epicenter is not absolutely
  predictive of serious structural damage, hospital
  evacuation, and demolition.
• Peak ground acceleration measurements are a
  better predictor of hospital damage

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Conclusion

• Evacuation can be coordinated by a central EOC or
  independently by the affected facility
• Hospitals should have a secondary evacuation plan
  that functions in the absence of central control
• A back-up plan should be in place that provides
  care for patients in case hospitals are rendered
  non-functional.

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