Abstract
Objectives
Umbilical cord blood gases (UBG) may be a critical element in the assessment of a depressed newborn infant but in some cases the arterial or venous UBG source is uncertain making clinical and/or medical-legal interpretation difficult. Objective: to estimate the probability of an arterial (ProbAS) or venous (ProbVS) UBG source depending on blood gas parameters in acidemic cases.
Methods
A total of 56,703 pairs of concomitant arterial and venous (CAV) UBG results assayed over an 8.8-year period were analyzed. Specimen pairs with preanalytical issues, duplicate source, or physiologically out-of-range or uninterpretable results were excluded. The 3,579 CAV-UBGs with an arterial and venous pH 6.70 to 7.25 were analyzed. Generalized additive model (gam)-based binomial logistic regressions were used to determine the ProbAS and ProbVS according to the blood gas parameters.
Results
The relative differences between arterial and venous medians were: pO2 ‒47%, pCO2 22%, pH −11%, and BD 4%. Below a median of 2.4 kPa, the lower the pO2, the higher the ProbAS. Above this value, the higher the pO2, the lower the ProbAS. An Excel worksheet is provided to calculate ProbAS and ProbVS from the regression model for different combinations of pH, pCO2, and pO2 values. Considering ProbAS and ProbVS above a cutoff 0.8, the model correctly identified the source in 56% of cases while 41% were indeterminant and 3% were erroneous.
Conclusions
The probability of an arterial or venous source of an umbilical blood gas can be estimated based on the pH, pCO2, and pO2 in most acidemic specimens.
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Research funding: Not applicable.
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Author contributions: Initial purpose and design: DM, RS; Data collection, analysis, statistics, and figures: DM; Neonatology expertise: RS; Laboratory expertise: DM; Writing: DM, RS. The two authors have accepted responsibility for the entire content of this manuscript and approved its submission.
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Competing interests: Dr. Stavis is the President of Grand Rounds Software, LLC; the company has no financial interest in the results of this study. Dr. Stavis is a consultant in a medical-legal case that involves, among other issues, the identification of the source of an umbilical cord blood gas. His compensation as a consultant is entirely independent of this study.
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Informed consent: Not applicable.
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Ethical approval: Not applicable.
References
1. Neonatal Encephalopathy and Neurologic, Outcome. Report of the American College of Obstetricians and Gynecologists’ task force on neonatal encephalopathy, 2nd ed. Washington, DC: ACOG, AAP; 2014. Reaffirmed 2019. Available from: https://www.acog.org/-/media/project/acog/acogorg/clinical/files/task-force-report/articles/2014/neonatal-encephalopathy-and-neurologic-outcome.pdf [Accessed 16 Jul 2022].Search in Google Scholar
2. Ross, MG. Forensic analysis of umbilical and newborn blood gas values for infants at risk of cerebral palsy. J Clin Med 2021;10:1676. https://doi.org/10.3390/jcm10081676.Search in Google Scholar PubMed PubMed Central
3. Ross, MG. Threshold of metabolic acidosis associated with newborn cerebral palsy: medical legal implications. Am J Obstet Gynecol 2019;220:348–53. https://doi.org/10.1016/j.ajog.2018.11.1107.Search in Google Scholar PubMed
4. Cantu, J, Szychowski, JM, Li, X, Biggio, J, Edwards, RK, Andrews, W, et al.. Predicting fetal acidemia using umbilical venous cord gas parameters. Obstet Gynecol 2014;124:926–32. https://doi.org/10.1097/aog.0000000000000517.Search in Google Scholar PubMed
5. Swanson, K, Whelan, AR, Grobman, WA, Miller, ES. Can venous cord gas values predict fetal acidemia? Am J Obstet Gynecol 2017;217:364.e1–364.e5. https://doi.org/10.1016/j.ajog.2017.05.047.Search in Google Scholar PubMed
6. Johnson, JW, Richards, DS. The etiology of fetal acidosis as determined by umbilical cord acid-base studies. Am J Obstet Gynecol 1997;177:274–82. https://doi.org/10.1016/s0002-9378(97)70187-x.Search in Google Scholar PubMed
7. Riley, RJ, Johnson, JWC. Collecting and analyzing cord blood gases. Clin Obstet Gynecol 1993;36:13–23. https://doi.org/10.1097/00003081-199303000-00005.Search in Google Scholar PubMed
8. Martin, GC, Green, RS, Holzman, IR. Acidosis in newborns with nuchal cords and normal Apgar scores. J Perinatol 2005;25:162–5. https://doi.org/10.1038/sj.jp.7211238.Search in Google Scholar PubMed
9. Westgate, J, Garibaldi, JM, Greene, KR. Umbilical cord blood gas analysis at delivery: a time for quality data. Br J Obstet Gynaecol 1994;101:1054–63. https://doi.org/10.1111/j.1471-0528.1994.tb13581.x.Search in Google Scholar PubMed
10. Tong, S, Egan, V, Griffin, J, Wallace, EM. Cord blood sampling at delivery: do we need to always collect from both vessels? BJOG 2002;109:1175–7. https://doi.org/10.1111/j.1471-0528.2002.01072.x.Search in Google Scholar PubMed
11. White, CR, Doherty, DA, Henderson, JJ, Kohan, R, Newnham, JP, Pennell, CE. Benefits of introducing universal umbilical cord blood gas and lactate analysis into an obstetric unit. Aust N Z J Obstet Gynaecol 2010;50:318–28. https://doi.org/10.1111/j.1479-828x.2010.01192.x.Search in Google Scholar PubMed
12. Kro, GA, Yli, BM, Rasmussen, S, Norèn, H, Amer-Wåhlin, I, Saugstad, OD, et al.. A new tool for the validation of umbilical cord acid-base data. BJOG 2010;117:1544–52. https://doi.org/10.1111/j.1471-0528.2010.02711.x.Search in Google Scholar PubMed
13. Monneret, D, Desmurs, L, Zaepfel, S, Chardon, L, Doret-Dion, M, Cartier, R. Reference percentiles for paired arterial and venous umbilical cord gases: an indirect nonparametric approach. Clin Biochem 2019;67:40–7. https://doi.org/10.1016/j.clinbiochem.2019.02.014.Search in Google Scholar PubMed
14. Low, JA, Panagiotopoulos, C, Derrick, EJ. Newborn complications after intrapartum asphyxia with metabolic acidosis in the term fetus. Am J Obstet Gynecol 1994;170:1081–7. https://doi.org/10.1016/s0002-9378(94)70101-6.Search in Google Scholar PubMed
15. Yeomans, ER, Hauth, JC, Gilstrap, LCIII, Strickland, DM. Umbilical cord pH, pCO2, and bicarbonate following uncomplicated term vaginal deliveries. Am J Obstet Gynecol 1985;51:798–800. https://doi.org/10.1016/0002-9378(85)90523-x.Search in Google Scholar PubMed
16. Thorp, JA, Sampson, JE, Parisi, VM, Creasy, RK. Routine umbilical cord blood gas determinations? Am J Obstet Gynecol 1989;161:600–5. https://doi.org/10.1016/0002-9378(89)90362-1.Search in Google Scholar PubMed
17. Dickinson, JE, Eriksen, NL, Meyer, BA, Parisi, VM. The effect of preterm birth on umbilical cord blood gases. Obstet Gynecol 1992;79:575–8.Search in Google Scholar
18. Helwig, JT, Parer, JT, Kilpatrick, SJ, Laros, RK. Umbilical cord blood acid-base state; what is normal? Am J Obstet Gynecol 1996;174:1807–14. https://doi.org/10.1016/s0002-9378(96)70214-4.Search in Google Scholar PubMed
19. Kotaska, K, Urinovska, R, Klapkova, E, Prusa, R, Rob, L, Binder, T. Re-evaluation of cord blood arterial and venous reference ranges for pH, pO2, pCO2, according to spontaneous or Cesarean delivery. J Clin Lab Anal 2010;24:300–4. https://doi.org/10.1002/jcla.20405.Search in Google Scholar PubMed PubMed Central
20. Reference manual for ABL800 FLEX series. Denmark: Radiometer Medical ApS; 2004. Available from: https://www.manualslib.com/manual/1220915/Radiometer-Abl800-Flex.html?page=164#manual [Accessed 9 Apr 2022].Search in Google Scholar
21. Wilson, SJ, Silverman, F, Young, BK. Fetal blood analysis. II. Effect of delayed assay on pH and lactate. Diagn Gynecol Obstet 1982;4:93–6.Search in Google Scholar
22. Hubert, M, Van der Veeken, S. Outlier detection for skewed data. J Chemometr 2008;22:235–46. https://doi.org/10.1002/cem.1123.Search in Google Scholar
23. Knowles, TP, Mullin, RA, Hunter, JA, Douce, FH. Effects of syringe material, sample storage time, and temperature on blood gases and oxygen saturation in arterialized human blood samples. Respir Care 2006;51:732–6.Search in Google Scholar
24. Dukić, L, Kopčinović, LM, Dorotić, A, Baršić, I. Blood gas testing and related measurements: national recommendations on behalf of the Croatian Society of Medical biochemistry and Laboratory Medicine. Biochem Med 2016;26:318–36. https://doi.org/10.11613/bm.2016.036.Search in Google Scholar PubMed PubMed Central
25. Matar, G, Poggi, B, Meley, R, Bon, C, Chardon, L, Chikh, K, et al.. Uncertainty in measurement for 43 biochemistry, immunoassay, and hemostasis routine analytes evaluated by a method using only external quality assessment data. Clin Chem Lab Med 2015;53:1725–36. https://doi.org/10.1515/cclm-2014-0942.Search in Google Scholar PubMed
26. Wood, SN. Generalized additive models: an introduction with R, 2nd ed. New York: Chapman and Hall/CRC Press; 2017.10.1201/9781315370279Search in Google Scholar
27. Wood, SN. ‘mgcv’: Mixed GAM computation vehicle with automatic smoothness estimation. R package version 1.8-40; 2022. Available from: https://cran.r-project.org/web/packages/mgcv/mgcv.pdf [Accessed 16 Apr 2022].Search in Google Scholar
28. Wood, SN. Low rank scale invariant tensor product smooths for generalized additive mixed models. Biometrics 2006;62:1025–36. https://doi.org/10.1111/j.1541-0420.2006.00574.x.Search in Google Scholar PubMed
29. Wickham, H. ggplot2: Elegant graphics for data analysis. New York: Springer-Verlag; 2016. ISBN 978-3-319-24277-4. Available from: https://ggplot2.tidyverse.org [Accessed 16 Jul 2022].10.1007/978-3-319-24277-4Search in Google Scholar
30. Simpson, G.: Graceful ggplot-Based Graphics and Other Functions for GAMs Fitted using mgcv. R package version 0.7.3; 2022. Available from: https://gavinsimpson.github.io/gratia/ [Accessed 16 Jul 2022].Search in Google Scholar
31. van Rij, J, Wieling, M, Baayen, R, van Rijn, H. itsadug: interpreting time series and autocorrelated data using GAMMs. R package version 2.4.1; 2022. Available from: https://cran.r-project.org/web/packages/itsadug/itsadug.pdf [Accessed 16 Jul 2022].Search in Google Scholar
32. Wang, Y, Zhao, S. Vascular biology of the placenta. San Rafael (CA): Morgan & Claypool Life Sciences; 2010. Available from: https://www.ncbi.nlm.nih.gov/books/NBK53247/ [Accessed 16 Jul 2022].Search in Google Scholar
33. Wentworth, P. Some anomalies of the foetal vessels of the human placenta. J Anat 1965;99:273–82.Search in Google Scholar
34. Huisjes, HJ, Aarnoudse, JG. Arterial or venous umbilical pH as a measure of neonatal morbidity? Early Hum Dev 1979;3:155–61. https://doi.org/10.1016/0378-3782(79)90004-5.Search in Google Scholar PubMed
35. Armstrong, L, Stenson, BJ. Use of umbilical cord blood gas analysis in the assessment of the newborn. Arch Dis Child Fetal Neonatal Ed 2007;92:F430–4. https://doi.org/10.1136/adc.2006.099846.Search in Google Scholar PubMed PubMed Central
36. Pomerance, JJ. Interpreting umbilical cord blood gases, 2nd ed. Los Angeles, California: BNMG Publishing Division; 2012.Search in Google Scholar
37. ACOG Committee on Obstetric Practice. ACOG Committee Opinion No. 348, November 2006: umbilical cord blood gas and acid-base analysis. Obstet Gynecol 2006;108:1319–22. https://doi.org/10.1097/00006250-200611000-00058.Search in Google Scholar PubMed
38. Leino, A, Kurvinen, K. Interchangeability of blood gas, electrolyte and metabolite results measured with point-of-care, blood gas and core laboratory analyzers. Clin Chem Lab Med 2011;49:1187–91. https://doi.org/10.1515/cclm.2011.185.Search in Google Scholar PubMed
39. Luukkonen, AA, Lehto, TM, Hedberg, PS, Vaskivuo, TE. Evaluation of a hand-held blood gas analyzer for rapid determination of blood gases, electrolytes and metabolites in intensive care setting. Clin Chem Lab Med 2016;54:585–94. https://doi.org/10.1515/cclm-2015-0592.Search in Google Scholar PubMed
40. De Koninck, AS, De Decker, K, Van Bocxlaer, J, Meeus, P, Van Hoovels, L. Analytical performance evaluation of four cartridge-type blood gas analyzers. Clin Chem Lab Med 2012;50:1083–91. https://doi.org/10.1515/cclm-2011-0685.Search in Google Scholar PubMed
Supplementary Material
The online version of this article offers supplementary material (https://doi.org/10.1515/cclm-2022-0772).
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