The Bohr effect related to blood and erythrocyte pH

Hilpert, Peter; Fleischmann, Renate Gislinde; Kempe, Doris; Bartels, H.

doi:10.1152/ajplegacy.1963.205.2.337

Cited by 146 publications

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“…Moreover base deficit calculation has been based on Hb buffering (13) of adult human red blood cells. The assumptions under which this construct was derived may not hold for sheep blood with fetal Hb and different Bohr and Haldane effects (30)(31)(32), and caution needs to be used in interpreting base deficit data for sheep blood.…”

Section: Discussionmentioning

confidence: 99%

Oxygen Transport and Metabolism in the Conscious Lamb: The Effects of Hypoxemia

1987

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Printedin U.S.A. METHODS Subjects.A total of seven lambs of mixed breed with documented dates of birth was studied. The lambs were surgically prepared and studied within 24 h after surgery. Two of these lambs, although in good health during the study, died after their initial study, one due to complications of an intracardiac catheter and another due to trauma. The lambs were studied multiple times over the next 2 to 3 months following surgery.Under lidocaine local analgesia, a Tygon catheter was placed either in a hindlimb or carotid artery and advanced into the aorta. A Tygon catheter or balloon flow directed catheter was passed through a jugular vein into the pulmonary artery while pressure was monitored to ensure proper placement. All newborn lambs had a second venous catheter inserted through either the 177 ABSTRACT. We studied the response of O 2 consumption, systemic O 2 transport, arterial blood lactate concentration, base deficit, and respiratory exchange ratio (C0 2 production/O, consumption) to graded alveolar hypoxia (fractional concentration of inspired oxygen 0.21, 0.16, 0.12, and 0.08) in seven intact, conscious chronically catheterized lambs at <1 wk after birth, at 25-40 days and at >40 days. To test whether there was an age related difference in the metabolic response to a decline in O 2 transport due to hypoxemia, we related the changes in blood lactate and base deficit to the systemic O2 transport and to the fractional change in O 2 consumption. Systemic O 2 transport and O 2 consumption decreased with severe hypoxemia, while lactate concentration and respiratory exchange ratio increased in all age groups. The changes in base deficit were not significant. When the hypoxemia-induced reduction in O 2 consumption was <15% of the baseline value (at fractional concentration of inspired oxygen 0.21) there was no elevation in lactate concentration; however, when O2 consumption was reduced by more than 15%, lactate concentration consistently increased by more than 1 mmol/ liter. There were no apparent differences amongst the age groups in this response. Therefore, the newborn lamb does show metabolic consequences of a fall in O2 consumption with hypoxemia which is similar to the older sheep, however, there is a "buffer zone" in which O2 consumption may decrease before evidence of tissue hypoxia can be found. The mechanism by which O 2 consumption can decrease without accumulation of lactate remains speculative. (Pediatr Res 22: 177-183, 1987 Supported by grants from the American Heart Association with funds contributed in part by the Connecticut Heart affiliate and from the National Institute of Child Health and Human Development HD-15834. M. M. and G. M. were supported by a National Heart, Lung and Blood Institute Training Grant HL-07272. G. L. is a recipient of an American Heart Established Investigatorship.In anesthetized adult subjects, the systemic O 2 consumption has been found to be independent of the systemic O 2 transport (product of arterial O 2 content and cardiac output) when the transpor...

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Section: Discussionmentioning

confidence: 99%

Oxygen Transport and Metabolism in the Conscious Lamb: The Effects of Hypoxemia

1987

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“…The Bohr effect factor for human haemoglobin is -0 5 (Hilpert et al 1963), meaning that the binding of one proton is accompanied by the release of two 02 molecules. The dose-response relations of methazolamide to the human Bohr effect in Tables 4 and 5 provide further quantification of the basic chemistry.…”

Section: T H Maren and E R Swenson Discussionmentioning

confidence: 99%

A comparative study of the kinetics of the Bohr effect in vertebrates.

Maren¹,

Swenson²

1980

The Journal of Physiology

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SUMMARY1. The kinetics of the Bohr effect and the role of carbonic anhydrase were studied in a series of representative vertebrates using a continuous flow rapid reaction apparatus.2. The rates of the Bohr effect in vertebrates are very similar, and differences among classes are manifestations of the ambient temperature.3. Complete carbonic anhydrase inhibition causes a fifteen to fortyfold reduction in the rate of the Bohr effect, sufficient to abolish its occurrence within capillary transit.4. There is a twenty-three-fold (duck) to 360-fold (man) excess of carbonic anhydrase activity in vertebrate red cells for the normal generation of the Bohr effect.5. When carbonic anhydrase is inhibited and CO2 hydration becomes rate limiting, the stoichiometry of the Bohr effect (Alog po2/ApH) is revealed in the ratio of the rates of proton formation in red cells to 02 release from haemoglobin.

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“…This was determined on fresh blood samples equilibrated in a tonometer for 30 min at 37OC, which permitted equilibration and sampling of successive aliquots of blood at different O2 tensions. Measurements of 0 2 saturation pH and PO2 provided the information for determining the Pm which was converted to pH 7.4 with a Bohr effect of 0.46 (7). There were at least four experimental points for each oxygendissociation curve.…”

Section: Methodsmentioning

confidence: 99%

Oxygenation in Anemic Newborn Lambs with High or Low Oxygen Affinity Red Cells

et al. 1981

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SummaryExperiments to determine the effect of the oxygen-hemoglobin dissociation curve on oxygen delivery during neonatal anemia, were carried out on 15 sedated and ventilated lambs less than 48 hr of age. Eight of the animals were exchange transfused with adult blood. The Pao of the exchange transfused group was 32.1 mm Hg (low Oz affinity) compared to 19.4 mm Hg for the controls (high 0 2 affinity). The animals were made anemic by isovolumic exchange transfusions with plasma. At different levels of hemoglobin defined as mild (8 mg/100 ml), moderate (6 mg/100 ml), and severe (4 mg/100 ml) anemia, tissue oxygenation, hemodynamic status, and blood gases were compared. Mixed venous POz was significantly lower in the high affinity group throughout the study. Cardiac output was significantly greater in the low affinity group during severe anemia. Oxygen consumption remained stable in the low affinity group, but decreased significantly in the high a f f i t y group when the anemia was severe. The data indicate that during severe anemia, blood with a high Po0 is more capable of adequately oxygenating tissues than that with a low PSO. SpeculationEarly preterm newborn infants may not adequately oxygenate their tissues during anemia because of their high oxygen a f f i t y red cells.An important adaptive mechanism during adult anemia is the shift to the right of the oxygen hemoglobin dissociation curve (15). Early preterm newborn infants have red cells with a relatively high oxygen affinity (3) and besides the numerous neonatal complications of prematurity these infants can also have a fall in hemoglobin level. It is apparent that a study was required to determine whether there could be obvious physiologic disadvantages of being anemic during a period of life when red cells have a high affinity for oxygen.In order to answer this question, studies were planned using the newborn lamb, within the first 48 hr of life, as an experimental model. The newborn lamb is born with a Pm which is similar to that of an early preterm newborn infant (18-19 mm Hg) (1) while the Pm of the adult sheep blood is considerably higher (3Ck38 mm Hg) (10). This study was designed to compare at different degrees of anemia, tissue oxygenation, hemodynamic status as well as blood gases in newborn lambs with either high or low oxygen affinity red cells. MATERIALS AND METHODSFifteen newborn lambs less than 48 hr old were included in the study. Eight lambs containing high oxygen affinity red cells were considered as the high 0 2 affiity group and seven lambs who underwent a two volume exchange transfusion (160 ml/kg) using freshly drawn maternal blood made up the low oxygen affiity group. The animals were prepared in conformance with the guiding principles in the care and use of animals as recommended by the Declaration of Helsinki. They were first sedated enough to be kept asleep with repeated subcutaneous injections of Diazepam (0.3 mg/kg every 20-30 min). To eliminate sensibility to pain during catheter position, lidocaine hydrochloride (2%) was used...

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The Bohr effect related to blood and erythrocyte pH

Cited by 146 publications

References 0 publications

Oxygen Transport and Metabolism in the Conscious Lamb: The Effects of Hypoxemia

Oxygen Transport and Metabolism in the Conscious Lamb: The Effects of Hypoxemia

A comparative study of the kinetics of the Bohr effect in vertebrates.

Oxygenation in Anemic Newborn Lambs with High or Low Oxygen Affinity Red Cells

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