Did Gary Morton Remarry After Lucy Died, The Chicken Connoisseur Net Worth, Articles C

NCCLS document H11-A4. has a master's degree in medical biochemistry and he has twenty years experience of work in clinical laboratories. In: McLaren A (ed): Advances in reproductive physiology. A limited number of studies [29-32] have been conducted to test this proposition and thereby validate the clinical use of cord-blood lactate measurement. EXAMPLE PROBLEMS ANSWERS. This is by far the most common time to assess acid-base balance. I understand that submitting this form does not create an attorney-client relationship. Arch, Duerbeck N, Chaffin D, Seeds J. So, the umbilical cord contains three blood vessels: one large vein carrying oxygenated blood to the fetus and two much smaller arteries carrying deoxygenated blood that is relatively rich in carbon dioxide and other metabolic waste products from the fetus. The change is a progressive decrease in pH and base excess, and increase in, The lack of consensus on this issue among national expert bodies is reflected in obstetric practice around the world; some obstetric units having a selective policy, whilst others are routinely performing cord blood gas analysis at all births. However, because lactic acid crosses the placenta relatively poorly, a significantly greater base deficit in arterial cord blood indicates the presence of umbilical vein occlusion with at least some interval of partially restored umbilical arterial blood flow. We serve the following localities: Baltimore; Prince George's County including Bowie, Laurel, Landover, Hyattsville; Anne Arundel County including Glen Burnie; Baltimore County including Cockeysville, Glyndon, Hunt Valley, Jacksonville, Lutherville-Timonium, Owings Mills, Parkville, Reisterstown. The key difference between arterial and venous blood gas is that arterial blood gas test uses a small blood sample drawn from an artery while venous blood gas test is a comparatively less painful test that uses a small blood sample drawn from a vein. Significant metabolic acidosis, widely defined as cord arterial blood pH <7.0 and base excess 12.0 mmol/L), occurs in around 0.5-1 % of deliveries [1]. Low pH levels caused by acidosis can result in hypoxic-ischemic encephalopathy, periventricular leukomalacia, seizures, brain hemorrhages, and cerebral palsy. This paper discusses considerations for interpretation of blood gases in the newborn period. In Geneva in 1821, a French nobleman Jacques Alexandre Le Jumeau, Vicomte de Kergaradec, became the Apgar scores and umbilical artery pH have traditionally been used as objective measures of 2022 Radiometer Medical ApS | kandevej 21 | DK-2700 | Brnshj | Denmark | Phone +45 3827 3827 | CVR no. Body Mass Index. Compensation can be seen when both the PCO 2 and HCO 3 rise or fall together to maintain a normal pH. In short, significant cord metabolic acidosis (pH <7.0 and base excess, Currently, the only effective treatment for HIE is controlled cooling of the baby to a rectal temperature of 34 0.5 C for 48-72 hours. HIE is thus a significant cause of perinatal death and birth-related permanent disability. In the intervillous space of the placenta, carbon dioxide diffuses from the fetus into the mothers blood and the mother can eliminate it by exhalation through her lung. An arterial blood gas (ABG) is a test that measures the oxygen tension (PaO 2 ), carbon dioxide tension (PaCO 2 ), acidity (pH), oxyhemoglobin saturation (SaO 2 ), and bicarbonate (HCO 3) concentration in arterial blood. Our specific aim was to develop a standardized clinical care pathway, ensuring timely identification and evaluation of neonates with umbilical-cord acidemia at risk for HIE.METHODS. All human beings including the fetus inside the uterus before birth depend on two gases, oxygen, and carbon dioxide are being exchanged, oxygen enters the body and carbon dioxide exits the body. Ron helped me find a clear path that ended with my foot healing and a settlement that was much more than I hope for. In summary, these studies have confirmed that cord-blood lactate concentration is a good predictor of cord-blood pH and base excess, and that it is at least as good as pH and base excess in predicting outcome. Eur J Obstet Reprod Biol 2012; 162: 21-23, Armstrong L, Stenson B. As previously discussed, when uteroplacental insufficiency causes fetal metabolic acidosis, the degree of metabolic acidosis is approximately the same in both umbilical venous and arterial samples. Tight nuchal cord and neonatal hypovolemic shock. For many years it has been standard obstetric practice to clamp the umbilical cord within seconds of birth, a policy that is, as discussed above, coincidentally fortuitous for the most accurate assessment of neonatal acid-base status. Maternal-fetal acid-base physiology. The contact form sends information by non-encrypted email, which is not secure. Delay in clamping by as little as 45 seconds after birth results in significant change in acid-base parameters [13-15]; the longer the delay, the greater is the change [16, 17]. Your body normally tightly regulates the amount of oxygen and carbon dioxide in your . Anion Gap = Na - (HCO + Cl) Gap-Gap Ratio =. Clin Obstet Gynecol 1993;36:3-12. Check out our full ABG interpretation guide if you want to learn more. KQ . However, arterial blood can be difficult to obtain due to weak pulses or patient movement. The intended purpose of this review article is to detail the clinical value of determining acid-base parameters particularly pH and base excess of umbilical-cord blood. The pH, PCO2, and base deficit change quite slowly in a completely occluded umbilical vessel, likely because much of the surrounding tissue (Wharton's jelly) has very little metabolic activity and accordingly utilizes very little oxygen and produces very little carbon dioxide. Wyckoff MH, Perlman JM, Laptook AR. Correpondence of this manuscript should be addressed to: Case 10: Umbilical Cord Occlusion with Terminal Fetal Bradycardia, Mild. Understanding and use of blood gas analysis enable providers to interpret respiratory, circulatory, and metabolic disorders. If a baby suffered from hypoxia that resulted in a birth injury, the blood cord gases can prove the legitimacy of the plaintiff's claim. Cord blood gas results were as follows: Interpretation The respiratory acidosis in the venous sample is mild; the base deficit is within normal limits. Expel all air bubbles. All you need to know is a few parameters: pH (Norm: 7.35 - 7.45); PCO2 - partial pressure of carbon dioxide (Norm: 35 - 45 mmHg); Cap both ends and mix 20 times by gentle inversion. The normal physiological difference between venous and arterial cord blood gas and acid-base values is described in Table I. Normal buffering mechanisms are overwhelmed by this acid influx, and pH falls below normal limits. Arterial Blood Gas (ABG) Analyzer - MDCalc Arterial Blood Gas (ABG) Analyzer Interprets ABG. Intrapartum care: Care of healthy women and their babies during childbirth. by Cathy Parkes July 17, 2020 Updated: January 18, 2023 2 min read 5 Comments. Median and centile ranges for umbilical cord blood gas and lactate values Median (5th-95th percentile) PH:7.27 (7.12 - 7.35) pO2:16.3 mmHg (6.2-27.6); PCO2:55.1 mmHg (41.9-73.5) Bicarbonate:24.3 mmol/L (18.8-28.2) Base excess:-3.00 mmol/L (-9.3 to +1.5) Lactate:3.7 mmol/L (2.0-6.7) Effects of birth-related events on central blood flow patterns. As the umbilical cord is compressed, blood flow in the umbilical vein may briefly slow prior to coming to a complete stop. The general goals of oxygen therapy in the neonate are to maintain adequate arterial P a O 2 and S a O 2, and to minimize cardiac work and the work of . Pediatr Res 2007;61:415-20. An ABG calculator is a tool that provides an easy way to determine the acid-base status by inputting the pH, PaCO2, and HCO3- values. Terminology and normal arterial blood gases . Vanhaesebrouck P, Vanneste K, de Praeter C, van Trappen Y. 26 Oct 2021. The authors declared no conflict of interest related to work presented in this manuscript. Likewise, any umbilical venoarterial PCO2 difference of greater than 18 mmHg also is associated with either cord occlusion with terminal fetal bradycardia or chronic fetal heart failure with terminal fetal bradycardia. Below, the venous and arterial cord gases each have been "normalized" to a \(P_{CO_{2}}\) of 38 and 49 mmHg (the mean normal venous and arterial \(P_{CO_{2}}\)), respectively, as is done artificially by the equation used to calculate the base deficit in blood gas analyzers. New York, Springer-Verlag; 1990, p91. As far as I am aware, cord occlusion with terminal bradycardia has never been studied separately as a cause of neonatal asphyxia. How much blood must you draw? Following tissue extraction of oxygen and nutrients, fetal blood returns to the placenta via two small umbilical arteries. Important issues surrounding cord blood sampling will also be discussed. ReadDr. Amos' full bio, the book about him "Lessons in Survival: All About Amos," and afictionalized account of his father's lifein the novel, "Through Walter's Lens.". Cord blood gas analysis is used to assess acid-base status of newborns and to diagnose and treat those who are acidemic. Program: Blood Gas Interpretation Chart, 3rd Ed (5-Pack) $ 30.00 Based on the Siggaard-Andersen Acid-Base Alignment Nomogram, this tool allows you to accurately interpret a neonatal blood gas result in seconds. Base excess is defined as the amount of strong acid that must be added to each liter of fully oxygenated blood to return the pH to 7.40 at a temperature of 37C and a pCO2 of 40 mmHg (5.3 kPa), while a base deficit (ie. Significant metabolic acidosis (i.e. Volume expansion is encouraged as part of advanced neonatal resuscitation if more basic care does not result in the desired improvement. The baby might have had poor circulation and perfusion shortly before being born or they could have experienced a physical head injury during delivery. There are also blood cord gas interpretation errors that inflate or deflate the child's hypoxia at birth. The book makes the distinction between acute and chronic disorders based on symptoms from identical ABGs. If the baby has a birth injury but their blood cord gases came back normal, the obstetrician can use the umbilical cord gas levels as evidence that the injury did not occur during delivery and was not caused by negligence. Annals of Medical and Health Sciences Research 2014; 4: 8-17, Kumar S, Paterson-Brown S. Obstetric aspects of hypoxic ischemic encephalopathy. If the episodes are severe enough or frequent enough, there may be insufficient time for complete recovery between episodes, and acid-base values will deteriorate over time. Australia and New Zealand J of Obstetrics and Gynaecology 2010; 50: 318-28, Get fertility advice personalized for you, Umbilical cord base excess or base deficit, needle aspiration of two blood samples (one venous, one arterial) from the excised clamped cord segment into pre-heparinized syringes. The doctor will clamp the umbilical cord quickly after childbirth. Anion Gap - 12 24-HCO. It should look like this: Now lets solve a problem using the tic tac toe method: ABG results are the following..pH 7.24, PCO2 75, HCO3 28. However, the differences between venous and arterial pH, PCO2, and base deficit are greater than usual. The standard technique of sampling cord blood for gas and acid-base analysis comprises three steps: clamping a segment of the cord removing the clamped cord segment needle aspiration of two blood samples (one venous, one arterial) from the excised clamped cord segment into preheparinized syringes 1. . ABG analysis can be easy! To my knowledge, all animal studies of fetal cord occlusion involve sudden and complete occlusion rather than any period of continued venous occlusion with the restored arterial flow. A capillary blood gas (CBG) is a test that involves puncturing and collecting a blood sample from an infant. Calcium Equivalents. If the two samples return similar results (i.e. Obstet Gynecol 1984; 63: 44-47, Valero J, Desantes D, Perales-Pulchat A. Eventual outcome depends on severity/site of brain injury; those with mild HIE survive with usually little or no long-term consequences, but most of those with moderate/severe HIE either die during the neonatal period or survive with severe and permanent neuro/psychological deficit, cerebral palsy is an outcome for some [8, 9]. Br J of Obstetrics and Gynaecology 1994; 101: 1054-63, Riley R, Johnson J. Effect of delayed sampling on umbilical cord arterial and venous lactate and blood gases in clamped and unclamped vessels. Usher R, Shephard M, Lind J. The purpose of this test is to analyze the neonate's ventilatory status by measuring the pH and carbon dioxide concentration in the blood. This reflects the fact that it is the umbilical vein that carries oxygenated blood rather than the umbilical artery. Test your knowledge on the web's most interactive blood gas learning tool. The primary cause of acidosis comes from the lack of adequate oxygen being transferred from the placenta to the baby. Analyzing cord blood gases (oxygen O2 and carbon dioxide CO2) from the umbilical artery is believed to be a good representation of the fetal acid-base status immediately before birth. Westgate JA, Bennett L, Gunn AJ. Cord blood P o2 and P co2 The blood gas analyser measures pH, P co2 and P o2 and then calculates base excess after normalising P co2. The umbilical vein is more easily compressed than the umbilical arteries because it has a thinner muscular wall, and the mean blood pressure in the vein (5) is lower than that in the arteries (6) by a factor of approximately ten. CRRT Clearance. Blood gas analysis is a commonly used diagnostic tool to evaluate the partial pressures of gas in blood and acid-base content. Pearls/Pitfalls pH PCO mm Hg HCO- mEq/L Sodium mEq/L Chloride mEq/L Albumin (17) However, there is no clear evidence that volume expansion is helpful in neonatal asphyxia. Venous cord blood analysis reflects a combination of maternal acid-base status and placental function . This site is protected by reCAPTCHA and the Google Privacy Policy and Terms of Service apply. mmol/L. Oxygen and nutrients diffuse across the placental membrane from maternal arterial blood and is transported to the fetus via a single large umbilical vein. However, doctors can also use blood cord gases to defend birth injury lawsuits as well. Respiratory acidosis refers to high acid levels caused by impaired lung function, leading to retained carbon dioxide in the lungs and bloodstream. Maternal reduced oxygen-carrying capability due to: - anemia respiratory diseasehypoventilation,seizure, traumasmoking, Maternal reduced oxygen-carrying capability due to:- anemia- carboxy- hemoglobinemia, Decreased uterine blood flow due to:hypotension (e.g.shock, sepsis)regional anesthesiamaternal positioning, Chronic maternal conditions:- diabetes- chronic hypertension- SLE- antiphospholipid syndrome, Excessive uterine activityhyperstimulation prolonged laborplacental abruption, Utero-placental dysfunctionplacental abruptionplacental infarction/dysfunction marked by intrauterine growth restriction, oligohydramnios or abnormal Doppler studieschorioamnionitis (infection), Umbilical cord compressionoligohydramnioscord prolapse or entanglementDecreased fetal oxygen-carrying capabilitysignificant anemia due to isoimmunization, maternal-fetal bleed or vasa previacarboxy- hemoglobinemia (if the mother is a smoker). There are maternal, uteroplacental, and fetal factors which can have an impact on umbilical cord blood gases. The slower the circulation is through the placenta, the greater the amount of oxygen diffusion from mother to fetus, and the higher the PO2 in the umbilical vein. Due to thicker, muscular and innervated walls, arteries are also more painful to puncture than veins. Immediately after birth, ideally before the babys first breath, an approximate 20-cm segment of cord must be isolated between two sets of two clamps. However, it seems safe to assume that a difference of 4 mmol/L or more is significant. As one erudite neonatologist summarized, "Just add water! Cord-blood metabolic acidosis which is characterized by reduced blood pH and decreased base excess (i.e. Two unresolved issues militate against the routine use of cord-blood lactate alone, at the current time. 2016, Medications. It evaluates the baby's general health by looking at five key parameters (1): Appearance: This parameter looks at the baby's skin color after birth. Use of volume expansion during delivery room resuscitation in near-term and term infants. The change is a progressive decrease in pH and base excess, and an increase in pCO2 and lactate. J Perinatol 2005;25:162-5. Thus venous cord blood reflects the combined effect of maternal acid-base status and placental function, whilst arterial cord blood reflects neonatal acid-base status. It is good to refreshed my knowledge about how to interpreter a blood gas result. Wykoff M, Garcia D, Margraf L, Perlman J, et al. Finally, the potential role of cord-blood lactate measurement will be discussed. The test also checks the balance of acids and bases, known as the pH balance, in your blood. Some experts define fetal acidemia as a pH of less than 7.1. Read our ABG Interpretation Guide. A difference between umbilical venous and arterial pHs greater than 0.10 is suggestive of cord occlusion with terminal bradycardia. Info | This calculator provides all the parameters derived from Stewart's theory of acid-base balance. Submitting a contact form, sending a text message, making a phone call, or leaving a voicemail does not create an attorney-client relationship. Umbilical venous pressure and Doppler flow pattern of inferior vena cava in the fetus. The blood volume of the newborn infant and placental transfusion. The results from cord blood gases are frequently used as evidence in medical malpractice lawsuits by both attorneys and doctors as a marker for the harm done to the child and to prove whether negligence was involved in a child's injury. and Towson; Carroll County including Westminster; Frederick County including Frederick; Harford County including Abingdon, Bel Air, Belcamp, and Forest Hill; Montgomery County including Germantown and Rockville; Howard County including Ellicott City and Columbia, Washington, D.C. and Washington County including Hagerstown. Eur J Obstet Gynecol Repro Biol. Okamura K, Murotsuki J, Kobayashi M, Yano M, et al. When this occurs, one should expect a higher PO. Delay in clamping by as little as 45 seconds after birth results in significant change in acid-base parameters [13-15]; the longer the delay, the greater is the change [16, 17]. WARNING. It was a good review of ABG analysis. The American College of Obstetricians and Gynecologists (ACOG) also favor a selective approach, stating that cord-blood testing should be applied in the following situations [22]: The Society of Obstetricians and Gynecologists of Canada (SOGC), by contrast, recommend that cord blood gas analysis be performed at all births [7]. Causticizing Efficiency Calculator. An arterial blood gas (ABG) test is a blood test that requires a sample from an artery in your body to measure the levels of oxygen and carbon dioxide in your blood. ANZJOG 2011; 51:17-21. Finbar omweri. The "P" in PO2 and PCO2 means "partial pressure", which is how the cord blood gases are measured. At term, normal mean umbilical venous blood pressure is 4.9 mmHg, whereas normal mean aortic blood pressure is about 52 mmHg. Learn more about Obiehere. Umbilical cord blood gas and acid-base analysis. When she inhales, she picks up oxygen into her blood that is carried to the placenta and fetus. This calculator only differentiates between acute (pH abnormal) and compensated (pH normal). There is currently a plague of 'venous' blood gases (VBG) in clinical practice. INSTRUCTIONS This analyzer should not substitute for clinical context. Blood is sampled into a preheparinized syringe by needle aspiration. A widened difference in PCO2 (18 mmHg or greater) in the absence of a widened pH difference is clinically quite rare. Early Human Development 2010; 86: 336-44, Kurinczuk J, White-Koning M, Badawi N. Epidemiology of neonatal encephalopathy and hypoxic-ischemic encephalopathy. pH : 7.36-7.44. The growing fetus depends for oxygen and nutrients on maternal blood supply. The respiratory acidosis in the venous sample is mild; the base deficit is within normal limits. Arterial Blood Gas (ABG) Interpretation: Practice Problems, Answers, & Cheatsheet. Cord blood gas analysis determines the fetal metabolic condition when umbilical circulation stops during childbirth. Box 51-1 describes an umbilical cord blood gas sampling procedure. The results of the analysis can show how healthy the baby is and determine if they have a birth injury. 7.35-7.45. pH < 7.35 indicates ACIDOSIS (ACID) Draw your tic tac toe . The infant was then delivered by outlet forceps. Widened differences also may be associated with fetal heart failure. accurately in order to calculate exact base excess. The wider the differences between umbilical venous and arterial samples, likely the longer the interval of umbilical vein obstruction with the restored umbilical arterial flow. Both umbilical cord blood venous or arterial values may be influenced by many different conditions including but not limited to: In order to examine the fetus' status, umbilical artery blood needs to be examined as this is the blood coming from the baby (as opposed blood going to the baby through the umbilical veins). Lactic acid is the principal metabolic acid responsible for the fall in cord-blood pH and base excess that is associated with cord-blood metabolic acidosis and birth asphyxia [28]. J Pediatr 1971;79:406-12. Introduction, indications and sources of errors 2. Use of umbilical cord blood gas analysis in the assessment of the newborn. FO . Remember, the umbilical vein is carrying . With intact umbilical-placental circulation, any metabolic acidosis appearing in the umbilical artery will almost instantaneously appear in the umbilical vein. Although widened pH differences are almost always associated with cord occlusion with terminal fetal bradycardia, rarely the pH difference falls within the normal range, 0.04 0.10. Johnson and Richards (7) have reported that in cases of umbilical cord prolapse, umbilical venous PO2, oxygen saturation, and oxygen content were all significantly greater than reference values. The calculator also determines whether the state is compensated or uncompensated. The analysis of cord blood respiratory gases and acid-base values is an important adjunct for determining the extent and cause of fetal acidosis at delivery. After the mother's blood is oxygenated, it is absorbed by the placenta's capillaries. This has medico-legal significance for resolving disputes about the cause of brain damage sustained at birth [11]. - diabetes Professor of Pathology, NYU School of Medicine. Your doctor may run a blood gas analysis or arterial blood gas (ABG) test if you are showing the signs of an oxygen, carbon dioxide, or pH imbalance such as confusion or difficulty breathing. Even on routine, vigorous deliveries, getting into this habit as part of your deliveries will help you be prepared. Sodium and chloride are required for anion gap calculation. Effect of delayed umbilical cord clamping on blood gas analysis. The question is how much oxygen the baby was getting. The capillaries will then deliver the blood to the placenta's main artery where it is finally transferred to the baby. cord blood pH <7.0 or base excess. Obstet Gynecol 2006; 108: 1319-22, Andersson O, Hellstrom-Westas L, Andersson D, Di Tommasso M, Seravalli V, Martini I. The intrapartum acid-base status, the status of the oxygen and other gases in the fetus and the umbilical cord after birth is important in establishing the link between events before and shortly after delivery. It is also important to get accurate results. Base excess is defined as the amount of strong acid that must be added to each liter of fully oxygenated blood to return the pH to 7.40 at a temperature of 37C and a pCO 2 of 40 mmHg (5.3 kPa). Together with other clinical measurements (including fetal heart rate [FHR] tracings, Apgar scores, newborn nucleated red cell counts, and neonatal imaging), cord gas analysis can be remarkably helpful in determining the cause for a depressed newborn. Yeomans ER, Hauth JC, Gilstrap LC III, Strickland DM. Normal values of umbilical arterial samples in a preterm newborn: *The P in PCO2 and PO2 stands for partial pressure, which is how these umbilical cord blood gases are measured. At time of cord clamp: Double clamp and divide a ~10-15 cm segment of cord and place on delivery table* * time for blood gas assessment: 60 minutes from clamped cord segment, 60 minutes in heparin flushed syringe at room temp. At birth, a 10- to 20-cm segment of umbilical cord is doubly clamped and cut. The validation of paired (arterial and venous) samples is based on minimum arterio-venous (A-V) differences for pH and pCO2 experimentally determined by Westgate et al [2]. The respiratory acidosis in the arterial sample is also mild, but there is also a mild metabolic acidosis. It is these infants who are most likely to benefit from volume expansion. Wider differences suggest a longer interval of umbilical vein obstruction with the restored umbilical arterial flow and greater fetal hypovolemia. Deorari , AIIMS 2008 2 Contents 1. May contain information that is not supported by performance and intended use claims of Radiometer's products. Since acid-base status is in flux during the perinatal period, the timing of isolating a sample for analysis is crucial. The pH, base excess and pCO2 (acid-base status) of arterial blood flowing through the umbilical cord provides valuable objective evidence of the metabolic condition of neonates at the moment of birth; a notion that has assured a role for the blood gas analyzer in hospital delivery suites in cases of suspected fetal distress/asphyxia. Instead, the exchange of gases, breathing occurs in the placenta where oxygen is transported from the mother's blood vessels into the placenta and then from the placenta through the umbilical cord to the fetus and carbon dioxide is exchanged from the fetus to the mother. NCCLS. The fetus does not breathe in the same way humans do outside the womb (although chest movement or practice breathing do happen inside the uterus before birth). Dunn PM. Unlike other blood samples obtained through a vein, a blood sample from an . The umbilical vein is much easier to occlude than the umbilical arteries. Blood gases can be performed from cord, arterial, venous or capillary specimens. Info. However, it is important to note that the ABG calculator should not be used as a substitute for clinical judgment. Although these arterial blood pressure measurements were taken in fetal sheep, they are thought to be a reasonable estimate for the human fetus. Of course, terminal cord occlusion does not preclude severe repetitive cord occlusion with insufficient time for even the PCO2 to fully recover between occlusive episodes or a preexisting or simultaneous occurrence of uteroplacental insufficiency. However, because lactic acid crosses the placenta poorly (1), a greater base deficit in the arterial cord blood sample indicates the presence of umbilical vein occlusion with at least some interval of partially restored umbilical arterial blood flow. Manor et al [18] determined that blood gas values of cord blood stored in a capped heparinized syringe remain sufficiently stable for an hour at room temperature. Wiberg et al [31] argue that lactate may be superior to base excess because the former is a direct measure of metabolic acidosis, whereas base excess is an indirect estimated (calculated) value derived from measured pH and pCO2. It is a red flag that indicates the presence of hypoxia during delivery. The other values impact pH and BE, but pH and BE are the main numbers examined to determine if the baby suffered from a lack of oxygen to the brain either shortly before .