Cesarean Delivery Surgical Site

Infection Rate Based on Hospital

Billing Data: Fact or Fiction?

Kelly W. Kline, MD

Mentor: Sharon Keiser, MD

Adam Tyson, MD

Department of Obstetrics & Gynecology

• I have no meaningful conflicts of interest to

disclose.

Background

• Why do we care about surgical site infections

(SSI)?

– Very common delivery method1

– 2-10% complicated by SSI2

– Very costly to patient and healthcare resources3

Background

• What is known about post-cesarean SSI?

– Prophylactic Antibiotics

– Surgical site preparation

Hypothesis

• The hospital-determined rate of post-

cesarean surgical site infection is significantly

lower than the true rate at our institution

Objectives

• Primary:

– Determination of an accurate post-cesarean SSI

rate

• Secondary:

– Identify modifiable risk factors for post-cesarean

SSI

Methods

Study Design

• Retrospective chart review

Participants

• L&D Delivery Log

• OB Teaching Staff cesarean deliveries

• July 1, 2014- June 30, 2015

Billing data participants

• All cesarean deliveries July 1, 2014- June 30, 2015

Methods

• Data Collection

– RedCap software

– 3 abstractors

– Clearly defined variables

• Demographic

• Pregnancy complications

• Intrapartum events

• Surgical Site Infection diagnosis

Methods

• 740 cesarean deliveries performed total

• ExclusionsCase Identifier Reason for Exclusion

A Exploratory laparotomy at time of cesarean delivery

B Exploratory laparotomy at time of cesarean delivery

C Cesarean hysterectomy for placenta accreta

D Cesarean hysterectomy for placenta accreta

E Cesarean hysterectomy for uterine rupture

F Exploratory laparotomy at time of cesarean delivery

G Cesarean hysterectomy for placenta percreta

Methods

• Billing data

– Provided by Infection Prevention department

– Admission log

– OR log

– CPT & ICD-9 codes

Methods: Statistics

• Continuous variables

– T- tests

• Comparison of women diagnosed with SSI

and not diagnosed with SSI

– Fisher’s exact test

Results- Primary Outcome

Information Source Proportion of SSI p-value

Billing Department

(n=1712)

11/ 1712 (0.6%) <0.00001

Charts (n=733) 60/733 (8.3%)

Results- secondary outcome

Demographics Overall (n=733) With SSI (n=60 ) Without SSI

(n=673)

p-value

Age 27.25 (0.22) 27.18 (0.92) 27.58 (0.23) 0.9376

Gravidity 2.75 (0.06) 2.62 (0.21) 2.76 (0.06) 0.4745

Parity 1.05 (0.04) 0.85 (0.12) 1.06 (0.04) 0.0472

Prior C-Section 377 (0.52) 25 (0.41) 352 (0.52) 0.1376

Hypertension 102 (0.14) 10 (0.17) 95 (0.14 0.5585

Ethnicity White 340 (0.47) 31 (0.52) 309 (0.46) 0.3281

Black 239 (0.33) 21 (0.35) 218 (0.32)

Other 152 (0.20) 8 (0.13) 144 (0.21)

Smoker 206 (0.28) 21 (0.35) 185 (0.27) 0.4453

Use of immunosuppressant 7 (0.01) 3 (0.05) 4 (0.01) 0.0145

Pre-pregnancy weight 180.23 (2.29) 190.83 (8.10) 179.4 (2.38) 0.1802

BMI 34.67 (1.00) 36.02 (3.041) 34.54 (1.05) 0.6622

Demographic Information

Results

Pregnancy

Complications

Overall (n=733) With SSI (n=60 ) Without SSI

(n=673)

p-value

Gestational

Diabetes

80 (0.11) 6 (0.10) 74 (0.11) 0.8064

Pre-eclampsia 117 (0.16) 12 (0.10) 105 (0.14) 0.3614

Gestational

Hypertension

51 (0.07) 7 (0.11) 44 (0.07) 0.1780

Systemic Infection

During Pregnancy

10 (0.01) 2 (0.03) 8 (0.01) 0.1941

Preterm Premature

Rupture of

membranes

(PPROM)

44 (0.06) 5 (0.08) 39 (0.06) 0.3959

Cerclage Placed 24 (0.03) 3 (0.05) 21 (0.03) 0.4378

Pregnancy Complications

Results

Intrapartum Overall (n=733) With SSI (n=60) Without SSI (n=673) p-value

Indication for

cesarean

section*

Previous C-section 342 (0.48) 19 (0.32) 323 (0.48) 0.0130

Arrest of Descent 27 (3.69) 6 (0.1) 31 (0.03) 0.0217

Arrest of Dilation 52 (0.07) 4 (0.07) 48 (0.07) 0.8882

Multiple Gestation 23 (0.03) 3 (0.05) 20 (0.03) 0.3906

Non-cephalic

Presentation

101 (0.14) 4 (0.07) 97 (0.15) 0.0939

Previous

Myomectomy

4 (0.006) 1 (0.016) 3 (0.005) 0.2199

Non-reassuring

fetal heart tracing

175 (0.24) 13 (0.22) 162 (0.24) 0.6637

Preterm Labor 8 (0.02) 0 8 (0.01) 0.3951

Failed Induction of

labor

57 (0.08) 9 (0.15) 48 (0.07) 0.0489

Other 61 (0.08) 5 (0.08) 56 (0.08) 0.9973

Skin Incision Pfannenstiel 713 (0.98) 59 (0.98) 654 (0.98) 0.6781

Vertical Midline or

High Transverse

18 (0.02) 1 (0.02) 17 (0.02)

Uterine

Incision

Low Transverse 672 (0.92) 52 (0.87) 620 (0.92) 0.1452

Classical 41 (0.06) 4 (0.07) 37 (0.06) 0.7668

High Transverse 20 (0.03) 4 (0.07) 16 (0.02) 0.0734

Type of

Fascial Suture

Vicryl 363 (0.50) 34 (0.57) 329 (0.50) 0.5089

PDS 341 (0.50) 26 (0.43) 341 (0.50) 0.2834

Other 1 (0.001) 0 1 (0.001)

Intrapartum and Delivery Characteristics

Results

Intrapartum Overall (n=733) With SSI (n=60) Without SSI

(n=673)

p-value

Labor 300 (0.41) 35 (0.58) 265 (0.40) 0.0045

Surgeon PGY 2.23 (0.02) 2.18 (0.47) 2.23 (0.57) 0.4482

Attending Scrubbed 237 (0.32) 18 (0.30) 219 (0.33) 0.0773

Diagnosed with Chorioamnionitis 58 (0.08) 5 (0.08) 53 (0.08) 0.8056

Maternal Tmax 99.07 100.01 (0.19) 98.99 (0.03) <0.0001

Maternal HR 106.63 (0.62) 112.52 (2.23) 106.10 (0.65) 0.0037

Hours of Rupture of Membranes 14.75 (3.25) 28.54 (10.92) 13.53 (3.43) 0.1935

Fetal HR*** 137.00 138.73 (3.05) 136.84 (0.71) 0.5476

Urgency of C-

Section

Scheduled 332 (0.46) 17 (0.29) 315 (0.48) 0.0077

Priority 241 (0.33) 26 (0.44) 215 (0.32) 0.0549

Urgent 92 (0.13) 8 (0.13) 84 (0.13) 0.8077

Emergency 56 (0.08) 4 (0.12) 49 (0.07) 0.2018

Type of Prep Chlorhexidine 637 (0.88) 46 (0.81) 591 (0.89) 0.0836

Povidone/ Iodine 82 (0.011) 10 (0.18) 72 (0.11) 0.1290

Other 3 (0.004) 1 (0.001) 2 (0.003) 0.2189

Intrapartum and Delivery Characteristics

Conclusions

• The hospital billing data at Greenville

Memorial Hospital are not an accurate

representation of our true surgical site

infection rate

Discussion

Superficial30%

Deep Incisional25%

Organ Space45%

Type of Wound Infection

Discussion

During Postpartum Stay, 24

OB Triage, 24

OBGYN Center, 9

Emergency Department, 1 Other Facility, 2

Location of Diagnosis

Discussion

During Postpartum Stay, 24

OB Triage, 24

OBGYN Center, 9

Emergency Department, 1

Other Facility, 2

Figure 3. Location of Diagnosis

Strengths

• Single primary abstractor

• Use of RedCap

• Did not rely on CPT codes for chart review

data

Weaknesses

• Multiple abstractors

• Billing data cases’ charts not reviewed

• Descriptive study

Future Research

• Vaginal Prep

• Identifying highest risk patients

• Prophylactic interventions

References

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