Predicting Daily Surgical Case Volume March 28, 2014 Association of Anesthesia Clinical Directors...
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Transcript of Predicting Daily Surgical Case Volume March 28, 2014 Association of Anesthesia Clinical Directors...
Predicting Daily Surgical Case Volume
March 28, 2014Association of Anesthesia Clinical Directors
Nashville, TN
Vikram Tiwari, Ph.D. William R Furman, MD
Warren S Sandberg, MD, Ph.D.
Department of Anesthesiology, Vanderbilt UniversityNashville, Tennessee
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Predicting Case Volume from the Accumulating Elective Operating Room Schedule Facilitates Staffing ImprovementsVikram Tiwari, Ph.D., William R. Furman, M.D., and Warren S. Sandberg, M.D., Ph.D.(Accepted for publication: Anesthesiology)
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Research MotivationMonth Budg. Actual Diff. % Diff.Aug-12 2924 3051 127 4.3%Sep-12 2448 2489 41 1.7%Oct-12 2813 2912 99 3.5%Nov-12 2673 2694 21 0.8%Dec-12 2565 2605 40 1.6%Jan-13 2813 2833 20 0.7%Feb-13 2491 2558 67 2.7%Mar-13 2678 2601 -77 -2.9%Apr-13 2837 2826 -11 -0.4%May-13 2754 2915 161 5.8%Jun-13 2688 2802 114 4.2%Jul-13 2815 2884 69 2.5%
Aug-13 2879 3019 140 4.9%
• Resources needed for DoS are planned usually weeks in advance
• Variability in daily surgical case volume sub-optimizes resources day
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Daily surgical volume time-series
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How to predict the daily volume?
• Elective case booking pattern – can that provide a signal?
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Research Questions
Working from the elective schedule as it develops over time, whether: 1. surgical case volume can be predicted, if so, 2. with what confidence3. how many days in advance4. and, if the predictions could be used to flex
staff up or down
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Linear trend of case bookings
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Days-Out Model
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Results / Model Output
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Putting the output to use – Daily Case Report
For the first 15 days of July (excluding weekends), the model’s predictions (at TMinus5) were within +/- 7 cases of the final volume 80% of the time, whereas the budgeted volume was within +/- 7 cases 40% of the time.
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Early wins!
• May – 2013– identified volume shortfall 12 days in advance,
arising due to all surgeons of a service attending a conference, without prior knowledge of the OR managers
• July 5th, 2013 (Friday)– identified 4 weeks in advance that volume would
be like a typical Friday, and no usual shortfall
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Spring Break Week of March 17, 2014
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How is the model’s output used?
Purpose Organization
Supply & Processes
1. Case cart preparation center2. Inpatient bed management
Staffing3. Anesthesiology Dept.4. OR Managers5. Surgical Pathology Labs6. Case cart preparation center
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Replication
• Children’s Hospital. Similar results.• Let’s collaborate to replicate this!
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Questions?
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Backup
• An Empirical Approach to Predicting Case Volume from the Accumulating Elective Operating Room Schedule Facilitates Operationally Useful Staffing Improvements
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Research Motivation
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• Model 2 Linear trend model– discarded
• Model 3 Percentage of final count– <brief description / figure 4?>
• Model 4 Days-out model– <description, keep Figure 6 in backup>
Methods: Linear models
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Methods: predicting daily volume
• Model 1: time-series of daily surgical volume
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Distribution of Case Bookings from 30 days prior to DoS
5% 10%
15%
20%
25%
30%
35%
40%
45%
50%
55%
60%
65%
70%
75%
80%
85%
90%
95%
100% Dist.
30 39% 72% 92% 99% 60%29 29% 62% 86% 95% 66%28 22% 53% 77% 94% 99% 77%27 45% 69% 88% 95% 50%26 36% 61% 85% 91% 99% 63%25 ~20% 34% 57% 79% 90% 99% 100% 65%24 27% 49% 73% 89% 98% 71%23 43% 68% 86% 98% 55%22 29% 56% 83% 94% 64%21 49% 72% 90% 99% 49%20 38% 63% 86% 95% 99% 61%19 30% 52% 80% 92% 99% 69%18 ~20% 25% 45% 73% 90% 99% 100% 74%17 34% 66% 88% 97% 63%16 21% 56% 82% 96% 99% 78%15 40% 68% 87% 99% 59%14 20% 51% 77% 91% 98% 78%13 34% 66% 84% 97% 63%12 21% 51% 76% 92% 99% 78%11 ~20% 40% 68% 86% 98% 99% 100% 59%10 25% 54% 82% 97% 99% 73%9 38% 72% 92% 98% 60%8 21% 51% 78% 94% 99% 78%7 32% 58% 86% 98% 66%6 19% 38% 68% 95% 100% 76%5 24% 51% 85% 99% 75%4 ~20% 38% 75% 92% 54%3 25% 60% 84% 99% 73%2 30% 71% 97% 66%1 11% 53% 96% 85%
100%
% of the Final Count
Num
ber o
f da
ys b
efor
e th
e da
y of
sur
gery
(Tm
inus
30 =
30
days
bef
ore
the
day
of s
urge
ry)
~20%
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Model 3: Percentage of Final Count
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