Sills MR. Inpatient capacity margin at children's hospitals during the fall 2009 H1N1 influenza pandemic. Presentation to the Colorado Emergency Medicine Research Center. 14 June 2010.

1. Inpatient capacity margin at
children's hospitals during the
fall 2009 H1N1 influenza
pandemic
Marion R. Sills, MD, MPH,

2. Objectives
• Objectives:
 Compare occupancy—non-ICU and ICU—during the fall
2009 pandemic to baseline numbers
 Measure how close each hospital came to threshold
occupancy—non-ICU and ICU
 Measure how much of an increase in ED admissions it
would have taken to fill each hospital (and each ICU)

3. Background
• March 2009: “swine flu” reported with 6% case fatality rate in
Mexico; Mexico City shut down
• April 2009: public health emergency declared in US
• April 2010: CDC estimate of
 H1N1 case fatality rate in US: 0.02% (0.006% in children 0-17 years)
 H1N1 case hospitalization rate: 0.45% (0.44% in children 0-17 years)

4. Background
• Case hospitalization and
case fatality rates much
less than prior pandemics

5. Background
• Per-population hospitalization rate comparable to
recent seasonal flu years

6. Methods
• Inpatient data from Pediatric Health Information System
(PHIS) database
• 41 children’s hospitals

7. Methods
Data
• All hospitalizations
 Non-ICU bed-days
 ICU bed-days
• Known # active beds
• Historic occupancy
data
• All ED visits for
influenza-like-illness
(23 hospitals)
Calculate
• Percent occupancy
by day (non-ICU,
ICU)
• ED ILI admission rate

8. Methods
• Objective 1: Compare occupancy—non-ICU and ICU—during
the fall 2009 pandemic to baseline numbers
• Same weeks (35-45) for 2008 (charted below)
• Seasonal flu (weeks 4-11 of 2009) for 2008-09

9. Methods
• Objective 2: Measure how close each hospital came to
threshold occupancy—non-ICU and ICU
• 2 definitions of threshold occupancy:
 Normative: 100% of all active beds occupied
 Relative: the own-hospital 95th percentile of occupancy (2008)

10. Methods
• Objective 2: Measure how close each hospital came to
threshold occupancy—non-ICU and ICU
 How best to express this?
• Proportion of days over threshold occupancy during pandemic period?
• Some component of duration: X weeks of Y% of days over threshold?
• Number of bed-days that could have been filled daily before threshold
occupancy was reached?
• Number of additional patients that could have been accepted daily
before threshold occupancy was reached?

11. Methods

12. Methods
• Part of the story: many children’s hospitals are already
nearing or over threshold occupancy (2006 data)

13. Methods
 Objective 3: Measure how much of an increase in ED
admissions it would have taken to fill each hospital (and each
ICU)
 For each hospital, calculate actual ED-to-non-ICU and ED-to-
ICU admit rate among all patients with ILI
 Calculate how much higher this rate would have had to be to
fill all beds
 Select a bad flu year (pandemic flu year? recent seasonal flu
year?) and re-do the modeling for Objective 2 to show how
full hospitals would have been, and how many excess beds
we would have needed (i.e., how many would have boarded
in the ED)

14. Methods
 Objective 3: Measure how much of an increase in ED
admissions it would have taken to fill each hospital (and each
ICU)
 Assumptions:
• All ED-to-hospital admissions with discharge diagnosis of
ILI had H1N1 influenza
• All inpatients with influenza were admitted via that
hospital’s ED
• ED-to-hospital admissions were distributed evenly
throughout the study period