Validation of the Siggaard–Andersen Acid–Base Nomogram for Hemoglobin F: Implications for Fetal Cord Blood Gas Analysis

Megan Whitham; Jayson Pagaduan; Steven L. Clark; Ila Singh; Michael Belfort; Sridevi Devaraj; Jing Cao; Anil Shetty; Shweta Pai; Karin Fox

doi:10.1055/s-0039-1677800

American Journal of Perinatology, Inhaltsverzeichnis

Am J Perinatol 2019; 36(14): 1481-1484
DOI: 10.1055/s-0039-1677800

Original Article

Thieme Medical Publishers 333 Seventh Avenue, New York, NY 10001, USA.

Validation of the Siggaard–Andersen Acid–Base Nomogram for Hemoglobin F: Implications for Fetal Cord Blood Gas Analysis

Megan Whitham

¹Department of Obstetrics and Gynecology, Texas Children's Hospital, Baylor College of Medicine, Houston, Texas

²Department of Pathology, Texas Children's Hospital, Baylor College of Medicine, Houston, Texas

,

Jayson Pagaduan

¹Department of Obstetrics and Gynecology, Texas Children's Hospital, Baylor College of Medicine, Houston, Texas

²Department of Pathology, Texas Children's Hospital, Baylor College of Medicine, Houston, Texas

,

Steven L. Clark

¹Department of Obstetrics and Gynecology, Texas Children's Hospital, Baylor College of Medicine, Houston, Texas

²Department of Pathology, Texas Children's Hospital, Baylor College of Medicine, Houston, Texas

,

Ila Singh

¹Department of Obstetrics and Gynecology, Texas Children's Hospital, Baylor College of Medicine, Houston, Texas

²Department of Pathology, Texas Children's Hospital, Baylor College of Medicine, Houston, Texas

,

Michael Belfort

¹Department of Obstetrics and Gynecology, Texas Children's Hospital, Baylor College of Medicine, Houston, Texas

²Department of Pathology, Texas Children's Hospital, Baylor College of Medicine, Houston, Texas

,

Sridevi Devaraj

¹Department of Obstetrics and Gynecology, Texas Children's Hospital, Baylor College of Medicine, Houston, Texas

²Department of Pathology, Texas Children's Hospital, Baylor College of Medicine, Houston, Texas

,

Jing Cao

¹Department of Obstetrics and Gynecology, Texas Children's Hospital, Baylor College of Medicine, Houston, Texas

²Department of Pathology, Texas Children's Hospital, Baylor College of Medicine, Houston, Texas

,

Anil Shetty

¹Department of Obstetrics and Gynecology, Texas Children's Hospital, Baylor College of Medicine, Houston, Texas

²Department of Pathology, Texas Children's Hospital, Baylor College of Medicine, Houston, Texas

,

Shweta Pai

¹Department of Obstetrics and Gynecology, Texas Children's Hospital, Baylor College of Medicine, Houston, Texas

²Department of Pathology, Texas Children's Hospital, Baylor College of Medicine, Houston, Texas

,

Karin Fox

¹Department of Obstetrics and Gynecology, Texas Children's Hospital, Baylor College of Medicine, Houston, Texas

²Department of Pathology, Texas Children's Hospital, Baylor College of Medicine, Houston, Texas

› Institutsangaben

Abstract

Objective The calculation of HCO₃ and base excess in current blood gas analysis is based on the Siggaard–Andersen equation. One of the constants in this equation is dependent on the known buffering capacity of hemoglobin A. We sought to investigate differences in buffering capacity between adult hemoglobin A and fetal hemoglobin F as a potential explanation for the observed poor correlation between calculated base excess in umbilical cord blood and newborn outcomes. Such differences would influence a key constant in the Van Slyke/Siggaard–Andersen equation used to calculate HCO₃ and base excess and could be an explanation of these observations.

Study Design This was a prospective observational study. We analyzed umbilical cord blood bicarbonate levels both as calculated values from a traditional blood gas analyzer and as measured values in 20 women giving birth at term. Since the calculated value is dependent upon the concentration and known buffering capacity of hemoglobin A, significant differences in these two analyses would imply differences in the buffering capacity of hemoglobins A and F.

Results The mean calculated HCO₃ value was 25 mEq/L (25.3 ± 1.9) compared with a mean measured value of 25 mEq/L (24.6 ± 1.7) over a range of pH levels of 7.16 to 7.42. This difference was not significant (p = 0.07).

Conclusion The buffering capacity of hemoglobin F, for clinical purposes, is not different than that of hemoglobin A and is not an explanation for the recognized poor correlation between base excess and neonatal outcome.

Keywords

hemoglobin F - acid base - base excess - oxygenation

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Referenzen

References
1 ACOG Committee on Obstetric Practice. ACOG Committee Opinion No. 348, November 2006: umbilical cord blood gas and acid-base analysis. Obstet Gynecol 2006; 108 (05) 1319-1322
2 Winkler CL, Hauth JC, Tucker JM, Owen J, Brumfield CG. Neonatal complications at term as related to the degree of umbilical artery acidemia. Am J Obstet Gynecol 1991; 164 (02) 637-641
3 Socol ML, Garcia PM, Riter S. Depressed Apgar scores, acid-base status, and neurologic outcome. Am J Obstet Gynecol 1994; 170 (04) 991-998
4 Low JA, Lindsay BG, Derrick EJ. Threshold of metabolic acidosis associated with newborn complications. Am J Obstet Gynecol 1997; 177 (06) 1391-1394
5 Cahill AG. Umbilical artery pH and base deficit in obstetrics. Am J Obstet Gynecol 2015; 213 (03) 257-258
6 Olofsson P. Determination of base excess in umbilical cord blood at birth: accessory or excess?. Am J Obstet Gynecol 2015; 213 (03) 259-261
7 Clark SL, Hamilton EH, Garite TJ. Current base deficit is not a relevant marker of neonatal metabolic acidosis [Reply]. Am J Obstet Gynecol 2017; 216: 536-537
8 Knutsen L, Svirko E, Impey L. The significance of base deficit in acidotic term neonates. Am J Obstet Gynecol 2015; 213: 373.e1-373.e7
9 Tuuli MG, Stout MJ, Shanks A, Odibo AO, Macones GA, Cahill AG. Umbilical cord arterial lactate compared with pH for predicting neonatal morbidity at term. Obstet Gynecol 2014; 124 (04) 756-761
10 Fagan DG, Lancashire RJ, Walker A, Sorahan T. Determinants of fetal haemoglobin in newborn infants. Arch Dis Child Fetal Neonatal Ed 1995; 72 (02) F111-F114
11 Siggaard Andersen O, Engel K. A new acid-base nomogram. An improved method for the calculation of the relevant blood acid-base data Scand. J Clin Invest 1960; 12: 177-186
12 Andersen OS. Blood acid-base alignment nomogram. Scales for pH, pCO2 base excess of whole blood of different hemoglobin concentrations, plasma bicarbonate, and plasma total-CO2. Scand J Clin Lab Invest 1963; 15: 211-217
13 Corey HE. Stewart and beyond: new models of acid-base balance. Kidney Int 2003; 64 (03) 777-787
14 Kellum JA. Clinical review: reunification of acid-base physiology. Crit Care 2005; 9 (05) 500-507
15 Perutz MF, Gronenborn AM, Clore GM, Fogg JH, Shih DT. The pKa values of two histidine residues in human haemoglobin, the Bohr effect, and the dipole moments of alpha-helices. J Mol Biol 1985; 183 (03) 491-498
16 Sears DW. Comparing the molecular structure differences between Hg F and Hg A that affect BPG binding. Available at: https://biosci.mcdb.ucsb.edu/biochemistry/tw-hbn/hbf/hbf-overview.htm . Accessed September 3, 2018
17 Chen W, Dumoulin A, Li X. , et al. Transposing sequences between fetal and adult hemoglobins indicates which subunits and regulatory molecule interfaces are functionally related. Biochemistry 2000; 39 (13) 3774-3781
18 Clark SL, Hankins GD. Temporal and demographic trends in cerebral palsy--fact and fiction. Am J Obstet Gynecol 2003; 188 (03) 628-633
19 Rosén KG, Murphy KW. How to assess fetal metabolic acidosis from cord samples. J Perinat Med 1991; 19 (03) 221-226
20 Cahill AG, Macones GA, Smyser CD, López JD, Inder TE, Mathur AM. Umbilical cord lactate correlates with brain lactate in term infants. Am J Perinatol 2017; 34 (06) 535-540
21 Brandis K. Bedside Rules for Assessment of Compensation. In: Acid-Base Physiology. Available at: https://www.anaesthesiamcq.com/AcidBaseBook/ab9_3.php . Accessed September 3, 2018