The in-vivo oxyhaemoglobin dissociation curve at sea level and high altitude

Balaban, Dahlia Y.; Duffin, James; Preiss, David; Mardimae, Alexandra; Vesely, Alex; Slessarev, Marat; Zubieta-Calleja, Gustavo; Greene, Ernest R.; MacLeod, David B.; Fisher, Joseph A.

doi:10.1016/j.resp.2012.12.011

Cited by 39 publications

(52 citation statements)

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“…This produces a left shift of the in vivo ODC between 50 and 90% SO 2, which is an advantage for oxygen loading. Recently similar results were found at 3600 m of altitude [13], [14]. Interestingly at low saturations “standardized” in vivo PO 2 /SO 2 pairs tend to lie right of the in vitro curve, especially in venous blood returning from exercising muscles [36]–[38], [55], [60].…”

Section: Discussionsupporting

confidence: 70%

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Hemoglobin Oxygen Affinity in Patients with Cystic Fibrosis

et al. 2014

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In patients with cystic fibrosis lung damages cause arterial hypoxia. As a typical compensatory reaction one might expect changes in oxygen affinity of hemoglobin. Therefore position (standard half saturation pressure P50st) and slope (Hill’s n) of the O2 dissociation curve as well as the Bohr coefficients (BC) for CO2 and lactic acid were determined in blood of 14 adult patients (8 males, 6 females) and 14 healthy controls (6 males, 8 females). While Hill’s n amounted to approximately 2.6 in all subjects, P50st was slightly increased by 1mmHg in both patient groups (controls male 26.7±0.2, controls female 27.0±0.1, patients male 27.7±0.5, patients female 28.0±0.3 mmHg; mean and standard error, overall p<0.01). Main cause was a rise of 1–2 µmol/g hemoglobin in erythrocytic 2,3-biphosphoglycerate concentration. One patient only, clearly identified as an outlier and with the mutation G551D, showed a reduction of both P50st (24.5 mmHg) and [2,3-biphosphoglycerate] (9.8 µmol/g hemoglobin). There were no differences in BCCO2, but small sex differences in the BC for lactic acid in the controls which were not detectable in the patients. Causes for the right shift of the O2 dissociation curve might be hypoxic stimulation of erythrocytic glycolysis and an increased red cell turnover both causing increased [2,3-biphosphoglycerate]. However, for situations with additional hypercapnia as observed in exercising patients a left shift seems to be a more favourable adaptation in cystic fibrosis. Additionally when in vivo PO2 values were corrected to the standard conditions they mostly lay left of the in vitro O2 dissociation curve in both patients and controls. This hints to unknown fugitive factors influencing oxygen affinity.

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Section: Discussionsupporting

confidence: 70%

“…The human fetus exists also at very low arterial PO 2 but the concentration of the high affinity fetal Hb (HbF) is increased. Recent in vivo determinations of the ODC in adults point to a possible left shift of its upper part at altitude [13], [14].…”

Section: Introductionmentioning

confidence: 99%

Hemoglobin Oxygen Affinity in Patients with Cystic Fibrosis

et al. 2014

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“…The ± 10% tolerance interval of future readings may seem excessively large but given the sigmoid nature of the oxygen-hemoglobin dissociation curve 22 , this may not be clinically significant. As an example, a reading of 75% S ct O 2 may be between 65% or 85%, but a value within this range does not suggest an imminent clinical threat to the patient.…”

Section: Discussionmentioning

confidence: 99%

The Accuracy of a Near-Infrared Spectroscopy Cerebral Oximetry Device and Its Potential Value for Estimating Jugular Venous Oxygen Saturation

Ikeda

MacLeod

Grocott

et al. 2014

Anesthesia &Amp; Analgesia

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Background An intriguing potential clinical use of cerebral oximeter measurements (SctO2) is the ability to noninvasively estimate jugular bulb venous oxygen saturation (SjvO2). Our purpose in this study was to determine the accuracy of the FORE-SIGHT® (CAS Medical Systems; Branford, CT), which is calibrated to a weighted average of 70% (SjvO2) and 30% arterial saturation, for Food and Drug Administration pre-market approval 510 (k) certification by adapting an industry standard protocol, ISO 9919:2005 [www.ISO.org] (used for pulse oximeters) and to evaluate the use of SctO2 and SpO2 measurements to noninvasively estimate jugular venous oxygen saturation (SnvO2). Methods Paired blood gas samples from the radial artery and the jugular venous bulb were collected from 20 healthy volunteers undergoing progressive oxygen desaturation from 100 to 70%. The blood sample pairs were analyzed via co-oximetry and used to calculate the approximate mixed vascular cerebral blood oxygen saturation, or reference SctO2 values (refSctO2), during increasing hypoxia. These reference values were compared to bilateral FORE-SIGHT SctO2 values recorded simultaneously with the blood gas draws to determine its accuracy. Bilateral SctO2 and SpO2 measurements were then used to calculate SnvO2 values which were compared to SjvO2. Results Two hundred forty-six arterial and 253 venous samples from 18 subjects were used in the analysis. The ipsilateral FORE-SIGHT SctO2 values showed a tolerance interval (TI) of [−10.72 10.90] Lin’s concordance correlation coefficient (CCC) with standard error (SE) of 0.83 ± 0.073 with the refSctO2 values calculated using arterial and venous blood gases. The combined data had a CCC of 0. 81 + 0.059 with TI of [−9.22 9.40] with overall bias was 0.09% and amplitude of the root mean square of error after it was corrected with random effects analysis was 2.92%. The bias and variability values between the ipsilateral and the contralateral FORE-SIGHT SctO2 measurements varied from person to person. The SnvO2 calculated from the ipsilateral SctO2 and SpO2 data showed a CCC + SE of 0.79 ± 0.088, TI = [−14.93 15.33], slope of 0.98, Y-Intercept of 1.14%) with SjvO2 values with a bias of 0.20% and an Arms of 4.08%. The SnvO2 values calculated independently from contralateral forehead FORE-SIGHT SctO2 values were not as correlated with the SjvO2 values (contralateral side CCC + SE = 0.72 ± 0.118, TI = [−14.86 15.20], slope of 0.66 and y-intercept of 20.36%). Conclusions The FORE-SIGHT cerebral oximeter was able to estimate oxygen saturation within the tissues of the frontal lobe under conditions of normocapnia and varying degrees of hypoxia (with 95% confidence interval of [−5.60 5.78] with ipsilateral blood ample data). These findings from healthy volunteers also suggest that the use of the calculated SnvO2 derived from SctO2 and SpO2 values may be a reasonable noninvasive method of estimating SjvO2 and therefore global cerebral oxygen consumption in the clinical setting. Further laboratory and clinical research is ...

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“…Whether SaO 2 is highest among Amhara Ethiopians, followed by Andeans, but lower in Tibetans (Beall et al, 1999;2006) or comparable in Tibetans and lowlanders at altitude (Keyl et al, 2000) varies among studies, although comprehensive analyses support the former (Moore, 2001;Wu et al, 2005;Beall, 2007;Weitz and Garruto, 2007). Reports of Hb-O 2 binding affinity in each of the highland populations also vary among studies (Morpurgo et al, 1976;Samaja et al, 1979;Moore et al, 1992;Balaban et al, 2003;Tashi et al, 2014), with recent report of an even lower P50 in Tibetans compared to Andean residents who also exhibit a greater O 2 -binding affinity (Balaban et al, 2003) at high altitude.…”

Section: Oxygen Saturation Binding Affinities In Highland Groupsmentioning

confidence: 98%

Altitude Adaptation: A Glimpse Through Various Lenses

Simonson

2015

High Altitude Medicine & Biology

133

141

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Simonson, Tatum S. Altitude adaptation: A glimpse through various lenses. High Alt Med Biol 16:125-137, 2015.-Recent availability of genome-wide data from highland populations has enabled the identification of adaptive genomic signals. Some of the genomic signals reported thus far among Tibetan, Andean, and Ethiopian are the same, while others appear unique to each population. These genomic findings parallel observations conveyed by decades of physiological research: different continental populations, resident at high altitude for hundreds of generations, exhibit a distinct composite of traits at altitude. The most commonly reported signatures of selection emanate from genomic segments containing hypoxia-inducible factor (HIF) pathway genes. Corroborative evidence for adaptive significance stems from associations between putatively adaptive gene copies and sea-level ranges of hemoglobin concentration in Tibetan and Amhara Ethiopians, birth weights and metabolic factors in Andeans and Tibetans, maternal uterine artery diameter in Andeans, and protection from chronic mountain sickness in Andean males at altitude. While limited reports provide mechanistic insights thus far, efforts to identify and link precise genetic variants to molecular, physiological, and developmental functions are underway, and progress on the genomics front continues to provide unprecedented movement towards these goals. This combination of multiple perspectives is necessary to maximize our understanding of orchestrated biological and evolutionary processes in native highland populations, which will advance our understanding of both adaptive and non-adaptive responses to hypoxia.

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The in-vivo oxyhaemoglobin dissociation curve at sea level and high altitude

Cited by 39 publications

References 82 publications

Hemoglobin Oxygen Affinity in Patients with Cystic Fibrosis

Hemoglobin Oxygen Affinity in Patients with Cystic Fibrosis

The Accuracy of a Near-Infrared Spectroscopy Cerebral Oximetry Device and Its Potential Value for Estimating Jugular Venous Oxygen Saturation

Altitude Adaptation: A Glimpse Through Various Lenses

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