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Travel-Time Analysis for Patients with Acute Respiratory Failure

David J. Wallace MD MPHAssistant Professor of Critical Care MedicineAssistant Professor of Emergency MedicineUniversity of Pittsburgh School of Medicine

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No conflicts of interest

Supported by NIH NHLBI-K12-HL109068

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Overview

• Background

– Respiratory failure

– Volume-outcome relationship

• Time-travel analysis

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Acute Respiratory Failure• Condition where not enough oxygen passes

from your lungs into your blood

• Many causes

– Pneumonia, asthma, heart failure

• > 30% mortality when treated in a hospital

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Acute Respiratory Failure• Treatment requires mechanical ventilation

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Annual Mechanical Ventilation Volume

Od

ds R

atio

for D

eath

2006

34% mortality

26% mortality75/year 550/year

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Volume-Outcome Relationship

Patients with respiratory failure who are treated at high-volume hospitals have improved outcomes

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Putting It All Together

• Respiratory failure has high mortality

• Respiratory failure requires specialized care

• High-volume hospitals have better outcomes

Should we concentrate patient care in high-volume hospitals?

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80 Hospitals 7 Regional Centers

Ideal Model Example: New Jersey

Regional Network

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How do you know the free market isn’t figuring this out on its own?

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Prescriptive Already Occurring?

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Objective One• For patients with acute respiratory failure,

compare travel-times from home to treating hospital, and from home to closest hospital

Treating Hospital

Closest Acute Care Hospital

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Objective Two• For patients with acute respiratory failure,

compare travel-times from home to treating hospital, and from home to closest high-volume hospital

Treating Hospital

High-Volume Hospital

High-Volume Hospital

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Methods: Patients• Pennsylvania state hospital discharge

records from 2007

• Adults with acute respiratory failure

• Patients living in Pennsylvania or within 25 miles of the state border (based on ZIP code)

• Hospital transfers excluded from analysis

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Methods: Hospitals• All acute care hospitals

• Hospitals with more than 400 discharges per year were classified as high-volume hospitals

• Street address used to geocode location

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Methods: Analysis• Unique patient ZIP code – hospital address

pairs were created using STATA software

– This was done to make computations in ArcGIS faster

• ArcGIS Network Analyst calculated travel-time from home to treating hospital, home to closest hospital, and finally home to closest high-volume hospital

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Results

• 31,322 adult cases of acute respiratory failure

• 132 low-volume hospitals

• 23 high-volume hospitals

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Results

• Median travel-time: 10 minutes 12 seconds

• Interquartile range: 4 minutes 55 seconds to 21 minutes 7 seconds

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Route to Treating Hospital

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Route to Closest Hospital

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Route to Closest High Volume Hospital

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How did the free market fare?

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The Low Hanging Fruit: 29%

High-Volume Hospital

Low-Volume Hospital

High-volume hospital was closest.

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The Excellent: 16%

Low-Volume Hospital

High-Volume Hospital

Treating hospital was not closest, but it was the closest high-volume hospital.

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The Understandable: 13%

Treating hospital was closest, but it was not a high-volume hospital

Low-Volume Hospital

High-Volume Hospital

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Needs Improvement: 15%

Treating facility was not closest, but the high-volume hospital was farther away

Low-Volume Hospital High-Volume

Hospital

Low-Volume Hospital

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Really Needs Improvement: 26%

Treating facility was not closest, and a high-volume hospital was closer

Low-Volume Hospital

High-Volume Hospital

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Summary of Actual Routes

Route Patients FrequencyHigh-Volume Hospital , but not closest hospital

5,034 16.1%

High-Volume Hospital and closest 9,203 29.4%Low-Volume Hospital and closest 4,210 13.4%Low-Volume Hospital , but not closest hospital

4,581 14.6%

Low-Volume Hospital , and High-Volume Hospital was closer

8,294 26%

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Conclusions

• 45% of patients with acute respiratory failure were treated at a high-volume hospital

– For 29% of patients, this was also the closest facility

• Without explicit policy or regulation, de facto regionalized care already exists for many patients with acute respiratory failure

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However…

• 55% of patients were not treated at high-volume hospitals

• Furthermore, 26% of patients were treated at a low-volume hospital when a high-volume hospital was closer

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Implications

• The majority of patients with acute respiratory failure are not getting care in high-volume hospitals

• Many patients travel farther to receive care in low-volume hospitals, a systems issue that should be targeted for improvement

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Co-Investigators

• Derek C. Angus

• Jeremy M. Kahn

• Kristen Kurland

• Donald Yealy

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www.ccm.pitt.edu/crisma