Materials and Methods
The Hospital Corporation of America is the nation’s largest provider of inpatient health care, including deliveries. The 110 affiliated hospitals with obstetric and newborn services in 21 states have an annual delivery volume of approximately 207,000, representing 5-6% of all deliveries in the United States. Demographic representation (both ethnic and payer mix) has been shown to mirror that of the US population as a whole.
The study population was singleton, term fetuses (gestation of ≥37 weeks) undergoing an induction of labor with oxytocin. Based on the annual delivery volume of each facility, we determined a sample size that would represent a statistically representative proportion of the entire population, using the Cochran’s sample size formula set for a 5% maximum error. All patient charts meeting the previously mentioned inclusion criteria were examined sequentially in a prospective manner beginning April 1, 2013, until the requisite sample size was reached. All chart reviews were completed by Sept. 30, 2013.
Each chart was individually reviewed by a regional nurse who was certified as an FHRM instructor by the Association of Women’s Health, Obstetric, and Neonatal Nurses. For each 30 minute segment of fetal heart rate tracing (FHRT) in which oxytocin was being infused, the FHR tracing was examined and data concerning the practices specified in Table 1 were collected. A chart was considered compliant if practices 1-3 ( Table 1 ) were documented for the labor in question prior to oxytocin infusion. Demonstration of practices 4-6 ( Table 1 ) was required in each applicable 30 minute segment to qualify as compliant.
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a At least 1 acceleration of 15 bpm × 15 seconds in 30 minutes is observed, or adequate variability is present for 10 of the previous 30 minutes; no more than 1 late deceleration occurred in the previous 30 minutes; no more than 2 variable decelerations exceeding 60 seconds in duration and decreasing greater than 60 bpm from the baseline occurred within the previous 30 minutes
b no more than 5 uterine contractions in 10 minutes for any 20 minute interval; no 2 contractions greater than 120 seconds; duration; uterus palpates were soft between contractions ; if intrauterine pressure catheter is in place, Montevideo units must calculate less than 300 mm Hg and the baseline resting tone must be less than 25 mm Hg.
Each of these practices has been recognized in the existing literature as a potentially important contributor to safe peripartum care, although the quality of supporting evidence varies. Details of the checklists referred to in Tables 1 and 2 have been previously published. Of note, for items 5 and 6 ( Table 1 ), it is suggested that unless each checklist element is present, the oxytocin dose should be reduced.
| Variable | NICU admission | 1 minute Apgar <7 | 5 minute Apgar <7 | Primary cesarean | |||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Adverse cases | Cases audited | Adverse, % | P value | Adverse cases | Cases audited | Adverse, % | P value | Adverse cases | Cases audited | Adverse, % | P value | Adverse cases | Cases audited | Adverse, % | P value | ||
| Estimated fetal weight reviewed prior to oxytocin | Yes | 396 | 10,672 | 3.7 | .58240 | 495 | 10,628 | 4.7 | .23360 | 78 | 10,629 | 0.7 | .91150 | 1858 | 10,672 | 17.4 | .43821 |
| No | 146 | 3726 | 3.9 | 155 | 3715 | 4.2 | 28 | 3716 | 0.8 | 670 | 3726 | 18.0 | |||||
| Adequacy of pelvis reviewed prior to oxytocin | Yes | 378 | 10,786 | 3.5 | .00544 | 464 | 10,745 | 4.3 | .03709 | 78 | 10,747 | 0.7 | .73655 | 1819 | 10,786 | 16.9 | .00018 |
| No | 164 | 3612 | 4.5 | 186 | 3598 | 5.2 | 28 | 3598 | 0.8 | 709 | 3612 | 19.6 | |||||
| Used preoxytocin checklist | Yes | 435 | 11,653 | 3.7 | .69638 | 528 | 11,604 | 4.6 | .87824 | 80 | 11,607 | 0.7 | .17124 | 2021 | 11,653 | 17.3 | .16336 |
| No | 107 | 2745 | 3.9 | 122 | 2739 | 4.5 | 26 | 2738 | 0.9 | 507 | 2745 | 18.5 | |||||
| Used in-use oxytocin checklist | Yes | 170 | 5868 | 2.9 | .00001 | 242 | 5846 | 4.1 | .06597 | 39 | 5847 | 0.7 | .42874 | 925 | 5868 | 15.8 | .00000 |
| No | 372 | 8530 | 4.4 | 408 | 8497 | 4.8 | 67 | 8498 | 0.8 | 1603 | 8530 | 18.8 | |||||
| Oxytocin stopped or decreased, abnormal UC | Yes | 44 | 1398 | 3.1 | .01194 | 67 | 1395 | 4.8 | .27307 | 11 | 1395 | 0.8 | .86764 | 275 | 1398 | 19.7 | .12855 |
| No | 194 | 4124 | 4.7 | 230 | 4115 | 5.6 | 37 | 4110 | 0.9 | 736 | 4124 | 17.8 | |||||
| Oxytocin stopped or decreased, abnormal FHR | Yes | 91 | 2364 | 3.8 | .00913 | 115 | 2352 | 4.9 | .00871 | 14 | 2353 | 0.6 | .03942 | 630 | 2364 | 26.6 | .00000 |
| No | 276 | 5272 | 5.2 | 338 | 5255 | 6.4 | 57 | 5254 | 1.1 | 923 | 5272 | 17.5 | |||||
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In addition, the outcomes data specified in Table 3 were collected for each patient. We then compared clinical outcomes among patients in whom each practice was followed with those among patients in whom these practices were not followed.
All data were submitted directly from the local site chart reviewer to an independent entity not affiliated with the Hospital Corporation of America (The Sullivan Group, Oakbrook Terrance, IL) for data compilation and statistical analysis. Composite system data and associated statistical evaluation were then made available to the authors and are presented here. Individual facility performance data were made available to local clinical and administrative leaders at these hospitals for quality improvement purposes.
Two-way contingency analysis was performed using a Fisher exact test, with a value of P < .05 considered significant. Number-needed-to-treat (NNT) calculations were performed using the standard formula of NNT = 1/ f a – f b where f a and f b represent the frequency of adverse outcome with or without a reduction in the dose of oxytocin.
Because this project involved only examination of deidentified aggregate data for quality improvement purposes, it was exempt from institutional review board approval based on 45CFR46.101(b)(2) and 46.102(f) as well as 45CFR164.514(a)-(c) of the Health Insurance Portability and Accountability Act.
Results
During this study period, 14,398 charts were prospectively examined as outlined in the previous text. Data regarding each of the specific practices described in Table 1 and associated clinical outcomes described in Table 3 are presented in Table 2 and Figures 1 and 2 . There was a significant correlation between a reduction in the dose of oxytocin based on the identification of specified abnormal FHR patterns ( Table 1 ) and all indicators of improved newborn outcome ( Table 2 ).
