Chapter 9. Radiological Point Source
This
chapter describes the assumptions for the radiological point source scenario,
including:
- The severity
categories.
- The arrival
pattern of casualties at the hospital(s).
- The length of
stay by hospital unit (i.e., ED, ICU, and the floor).
- The path
probability within the hospital(s) and the length of stay.
- The overall
outcome probabilities (i.e., probability of discharge and probability of death).
- The assumed level
of resource consumption per patient per day per hospital unit.
Footnotes
in the text of a particular section refer to references at the end of the
section. In the absence of specific references, parameter estimates were
obtained from general references listed in the Hospital Module section.
9.1 Severity
Categories
For the
point source scenario, patients arrive at the hospital(s) in one of two
conditions:
-
Mild: nausea, vomiting, anorexia, fever,
infections.
- Moderate: more severe mild symptoms, plus
bleeding, fatigue, and weakness.
- Severe: more severe moderate symptoms, plus
headache, prostration, dizziness, and disorientation
Users have
the option of specifying either the number and type or simply the
number of casualties who present at their hospital(s).
If the user
specifies only the number of casualties, the model assumes the casualties
arriving at the hospital(s) are randomly selected from among all casualties
from the attack. The distribution of casualty types in this case is as follow:
Casualty
Condition
|
Percent
|
Mild: nausea, vomiting, anorexia,
fever, infections |
28.8% |
Moderate: more severe as above, plus
bleeding, fatigue, and weakness |
32.6% |
Severe: more severe as above, plus
headache, prostration, dizziness, and disorientation |
38.6% |
This
breakdown by casualty condition is based on work performed during development of
the original Surge Model in 2005. In brief, we modeled a scenario in which
radioactive material was placed in several public locations. Based upon the
physical dimensions of an average person, the penetration rate of radiation,
and the density of crowds at various times, we calculated the number of people
exposed to different levels of radiation. Using available data on dose-response
to radiation in humans, we calculated the likelihood of experiencing GI
distress, blood symptoms, or mental effects from the radiation and categorized
casualties into the three categories listed above.
9.2 Casualty
Arrival Pattern
Casualties
are assumed to present at the hospital(s) when symptoms appear. For the this
scenario, casualties are expected to present in approximately equal numbers for
as long as the device remains undetected. This assumes that the number of
people at the facility where radioactive material is placed does not vary
widely from day to day. Once the material is identified and removed, the
exposure to new individuals ceases.
9.3 Length of
Stay By Hospital Unit
The
assumed average length of stay (in days) of patients the ED, ICU, and the floor
are:
Average
LOS by Hospital Unit
|
Mild
|
Moderate
|
Severe
|
ED |
1 |
1 |
1 |
Floor, not
via ICU |
1 |
4 |
7 |
Floor, via
ICU |
2 |
4 |
14 |
ICU |
1 |
12 |
28 |
9.4 Combined
Path Probabilities and Lengths of Stay
The table below shows the assumed probabilities of different
"paths" through the hospital(s).
Path
|
Mild
|
Moderate
|
Severe
|
ED → Discharge |
0% |
0% |
0% |
ED → Death |
0% |
0% |
0% |
ED → Floor → Discharge |
90% |
61% |
4% |
ED → Floor → Death |
0% |
0% |
0% |
ED → Floor → ICU → Death |
0% |
3% |
2% |
ED → Floor → ICU → Floor → Discharge |
0% |
11% |
2% |
ED → Floor → ICU → Floor → Death |
0% |
0% |
0% |
ED → ICU → Death |
0% |
5% |
43% |
ED → ICU → Floor → Discharge |
10% |
19% |
40% |
ED → ICU → Floor → Death |
0% |
1% |
7% |
The breakdown of length of stay by patient type summed over
all paths is:
Average LOS by Patient Outcome
|
Mild
|
Moderate
|
Severe
|
Survivors |
2.20 |
9.25 |
39.84 |
Fatalities |
2.51 |
8.82 |
17.12 |
Average Combined |
2.20 |
9.21 |
27.79 |
9.5 Overall
Outcome Probabilities
Based on
these inputs, the overall discharge and death probabilities are:
Outcome
|
Mild
|
Moderate
|
Severe
|
Discharge |
100% |
91% |
47% |
Death* |
0% |
9% |
53% |
*Note: These figures do not include
late (>2 months) mortality from radiation exposure.)
9.6 Resources
Consumed Per Patient Per Day
The assumed
level of resource consumption per patient per day is shown in the table below:
Resource
|
Units
|
Category
|
Subcategory
|
Lambda1
|
Mild
|
Moderate
|
Severe |
ED |
ICU |
Floor |
ED |
ICU |
Floor | ED |
ICU |
Floor |
Med/Surg Bed |
One Bed |
Capacity |
Floor |
1 |
0.083 |
0 |
0 |
0.083 |
0 |
0 |
0.083 |
0 |
0 |
ICU Bed |
One Bed |
Capacity |
ICU |
1 |
0 |
1 |
0 |
0 |
1 |
0 |
0 |
1 |
0 |
Burn Bed |
One Bed |
Capacity |
Burn |
1 |
0 |
0 |
0 |
0 |
0 |
0 |
0 |
0 |
0 |
Operating Room |
One OR Suite |
Capacity |
OR |
1 |
0 |
0 |
0 |
0 |
0 |
0 |
0 |
0 |
0 |
Airborne Isolation Room |
One Bed |
Capacity |
Isolation |
0.9 |
0 |
0 |
0 |
0 |
0 |
0 |
0 |
0 |
0 |
Intensivists (CCM) |
FTE |
Staff |
CCM |
0.7 |
0.021 |
0.083 |
0 |
0.021 |
0.083 |
0 |
0.083 |
0.083 |
0 |
Critical care nurses (CCN) |
FTE |
Staff |
CCN |
1 |
0.021 |
0.33 |
0 |
0.021 |
0.33 |
0 |
0.083 |
0.33 |
0 |
Surgeons |
FTE |
Staff |
Surgeon |
0.3 |
0 |
0.042 |
0 |
0 |
0.042 |
0 |
0 |
0.042 |
0 |
Non-intensivists (MD) |
FTE |
Staff |
MD |
0.9 |
0.167 |
0 |
0.042 |
0.167 |
0 |
0.042 |
0.167 |
0 |
0.042 |
Non-critical
care nurses (RN/LPN) |
FTE |
Staff |
RN |
1 |
0.042 |
0 |
0.146 |
0.042 |
0 |
0.146 |
0.042 |
0 |
0.146 |
Respiratory Therapists (RT) |
FTE |
Staff |
RT |
0.7 |
0 |
0.083 |
0 |
0 |
0.083 |
0 |
0.083 |
0.083 |
0 |
Radiology machines |
Machine Time |
Lab/Radiology |
Radiology |
0.3 |
0 |
0.021 |
0 |
0 |
0.021 |
0 |
0 |
0.021 |
0 |
Radiologic Technicians |
FTE |
Staff |
Rad Tech |
0.3 |
0 |
0.021 |
0 |
0 |
0.021 |
0 |
0 |
0.021 |
0 |
Pharmacists (PharmD/RPh) |
FTE |
Staff |
Pharmacist |
0.7 |
0.021 |
0.042 |
0.042 |
0.021 |
0.042 |
0.042 |
0.021 |
0.042 |
0.042 |
Mechanical ventilator |
Machine Time |
Capacity |
Ventilator |
0.9 |
0 |
0 |
0 |
0 |
0 |
0 |
0 |
0 |
0 |
Ventilator equipment |
One Ventilator |
Equipment |
Vent Tubing |
0.9 |
0 |
0 |
0 |
0 |
0 |
0 |
0 |
0 |
0 |
Oxygen (O2) |
24h O2 for Vent |
Supplies |
Oxygen |
0.9 |
0 |
1 |
0 |
0 |
1 |
0 |
0 |
1 |
0 |
Oxygenation monitoring equipment |
Machine Time |
Equipment |
O2 Monitoring |
0.9 |
0.083 |
1 |
0 |
0.083 |
1 |
0 |
0.083 |
1 |
0 |
Surgical supplies |
Trauma Set |
Supplies |
Surgical |
0.3 |
0 |
0 |
0 |
0 |
0 |
0 |
0 |
0 |
0 |
Radiology supplies |
Radiographic Film |
Supplies |
Radiological |
0.3 |
0 |
1 |
0 |
0 |
1 |
0 |
0 |
1 |
0 |
Cirprofloxacin or Doxycycline |
400mg/100mg bid |
Pharmacy |
Antibiotics |
1 |
0 |
0 |
0 |
0 |
0 |
0 |
0 |
0 |
0 |
Rifampin or other 2nd line agent |
600mg po bid |
Pharmacy |
Antibiotics |
1 |
0 |
0 |
0 |
0 |
0 |
0 |
0 |
0 |
0 |
Antibiotcs
for Secondary Pneumonia |
Assorted |
Pharmacy |
Antibiotics |
1 |
0 |
1 |
0 |
0 |
1 |
0 |
0 |
1 |
0 |
Surgical Infection Prophylaxis/Treatment |
Assorted |
Pharmacy |
Antibiotics |
1 |
0 |
0 |
0 |
0 |
0 |
0 |
0 |
0 |
0 |
Neutropenia Prophylaxis/Treatment |
Assorted |
Pharmacy |
Antibiotics |
1 |
0 |
0 |
0 |
1 |
1 |
1 |
1 |
1 |
1 |
Antibiotics intravenous infusion set |
One IV Piggyback |
Supplies |
IV set |
1 |
0 |
0 |
0 |
0 |
0 |
0 |
1 |
0.5 |
0.5 |
Hemodynamic medications |
Assorted |
Pharmacy |
Hemodynamic |
0.7 |
0 |
1 |
0 |
0 |
1 |
0 |
0 |
1 |
0 |
Intravenous fluids |
24h LR or equiv. |
Pharmacy |
IVF |
0.7 |
1 |
1 |
1 |
1 |
1 |
1 |
1 |
1 |
1 |
Intravenous infusions set |
One IV Set |
Supplies |
IV Set |
0.7 |
1 |
1 |
1 |
1 |
1 |
1 |
1 |
1 |
1 |
Laboratory machines |
Machine Time |
Lab/Radiology |
Laboratory |
0.7 |
0.042 |
0.083 |
0.042 |
0.042 |
0.083 |
0.042 |
0.083 |
0.166 |
0.083 |
Laboratory supplies |
CBC/CMP Reag. |
Supplies |
Laboratory |
0.7 |
2 |
2 |
2 |
2 |
2 |
2 |
3 |
6 |
3 |
Temperature monitoring equipment |
Machine Time |
Equipment |
Temperature |
1 |
0.083 |
1 |
0 |
0.083 |
1 |
0 |
0.083 |
1 |
0 |
Thromboembolism prophylaxis |
Enoxaparin 40mg sc
qd |
Pharmacy |
DVT Prophylaxis |
1 |
0 |
1 |
0 |
0 |
1 |
0 |
0 |
1 |
0 |
Urine output monitoring equipment |
Catheter and Bag |
Equipment |
U/O |
1 |
0 |
1 |
0 |
0 |
1 |
0 |
0 |
1 |
0 |
Universal Precautions PPE |
Glove/gown/mask |
PPE |
Universal |
1 |
1 |
1 |
1 |
1 |
1 |
1 |
1 |
1 |
1 |
Chemical PPE |
Level D |
PPE |
Chemical |
0.3 |
0 |
0 |
0 |
0 |
0 |
0 |
0 |
0 |
0 |
Radiological PPE |
Level D |
PPE |
Radiological |
0.3 |
1 |
1 |
1 |
1 |
1 |
1 |
1 |
1 |
1 |
Waste Disposal |
Level D |
PPE |
Decon Waste |
0.3 |
1 |
1 |
1 |
1 |
1 |
1 |
1 |
1 |
1 |
Mortuary Decontamination Materials |
Level D |
PPE |
Mortuary |
0.3 |
0 |
0 |
0 |
0 |
0 |
0 |
0 |
0 |
0 |
Atropine sulfate |
2mg |
Pharmacy |
Atropine |
0.1 |
0 |
0 |
0 |
0 |
0 |
0 |
0 |
0 |
0 |
Pralidoxime |
2g |
Pharmacy |
Pralidoxime |
0.1 |
0 |
0 |
0 |
0 |
0 |
0 |
0 |
0 |
0 |
Diazepam |
10mg |
Pharmacy |
Diazepam |
0.1 |
0 |
0 |
0 |
0 |
0 |
0 |
0 |
0 |
0 |
EEG |
Machine Time |
Equipment |
Chemical |
0.1 |
0 |
0 |
0 |
0 |
0 |
0 |
0 |
0 |
0 |
IV Steroids |
Hydrocortisone
50mg IV q6h |
Pharmacy |
Steroids |
0.7 |
0 |
0 |
0 |
0 |
0 |
0 |
0 |
0 |
0 |
DPTA |
1g IV |
Pharmacy |
DPTA |
0.1 |
0 |
0 |
0 |
0 |
0 |
0 |
0 |
0 |
0 |
Prussian blue |
3mg po tid |
Pharmacy |
Prussian Blue |
1 |
0 |
0 |
0 |
0 |
0 |
0 |
0 |
0 |
0 |
Growth Factors |
Pegfilgrastim 6mg
sc qw |
Pharmacy |
Growth factors |
1 |
0 |
0 |
0 |
1 |
1 |
1 |
1 |
1 |
1 |
Stem Cell Transfusion |
Unit of Use |
Heme/Onc |
Stem Cell Trans |
1 |
0 |
0 |
0 |
0 |
1 |
0 |
0 |
1 |
0 |
Geiger counter |
Machine Time |
Equipment |
Radiation |
0.1 |
0.42 |
0.21 |
0.21 |
0.42 |
0.21 |
0.21 |
0.42 |
0.21 |
0.21 |
Enteral feedings (3/day/patient) |
Unit of Use |
Nutrition |
Enteral |
1 |
0 |
0 |
0 |
0 |
0.5 |
0 |
0 |
1 |
0.5 |
Oral food (3 meals per day per patient) |
Unit of Use |
Nutrition |
Oral |
1 |
0 |
0.5 |
1 |
0 |
0.5 |
1 |
0 |
0.5 |
1 |
Sheet change |
1 linen change |
Housekeeping |
Laundry |
1 |
1 |
1 |
1 |
1 |
1 |
1 |
1 |
1 |
1 |
Patient infection control |
FTE |
Epidemiology |
Infection Control |
0.5 |
0.021 |
0.042 |
0.042 |
0.021 |
0.042 |
0.042 |
0.021 |
0.042 |
0.042 |
Engineering |
FTE |
Engineering |
Facility |
0.7 |
0.042 |
0.083 |
0.042 |
0.042 |
0.083 |
0.042 |
0.042 |
0.083 |
0.042 |
Janitorial/Housekeeping |
FTE |
Housekeeping |
Janitorial |
1 |
0.125 |
0.125 |
0.083 |
0.125 |
0.125 |
0.083 |
0.125 |
0.125 |
0.083 |
Nutrition |
FTE |
Nutrition |
Counseling |
0.5 |
0 |
0.083 |
0.083 |
0 |
0.083 |
0.083 |
0 |
0.083 |
0.083 |
Psychological support |
FTE |
Ancillary |
Psychologist |
0.5 |
0 |
0 |
0.042 |
0 |
0 |
0.042 |
0 |
0 |
0.042 |
Mortuary |
FTE |
Mortuary |
Morgue |
0.1 |
0 |
0.042 |
0.042 |
0 |
0.042 |
0.042 |
0.042 |
0.042 |
0.042 |
1. Lambda captures the resource requirement decay rate for a resource. Lambda = 1
implies no decay; the patient requires a constant amount of the resource while
s/he is hospitalized. Lambda <1 implies that less of the resource is
required each day the patient is hospitalized. Go to section 2.2 for details.
9.7
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Bland SA.
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Gusev I, Guskova
A, Mettler F, eds. Medical management of radiation accidents, 2nd ed. Boca Raton: CRC
Press; 2001.
4.
Mettler FA Jr.
Medical resources and requirements for responding to radiological terrorism. Health Phys
2005;89(5):488-93.
5.
Schleipman
AR, Gerbaudo VH, Castronovo FP Jr. Radiation disaster response: preparation and simulation
experience at an academic medical center. J Nucl Med Technol 2004;32(1):22-7.
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Timins JK, Lipoti
JA. Radiological terrorism. N J Med 2003;100(6):14-21.
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Turai I, Veress
K, Günalp B, et al. Medical response to radiation incidents and radionuclear
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Wheeler DS, Poss
WB. Mass casualty management in a changing world. Pediatr Ann 2003;32(2):98-105.
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