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Konrad E Bloch - One of the best experts on this subject based on the ideXlab platform.

  • does venous Blood Gas Analysis provide accurate estimates of hemoglobin oxygen affinity
    Annals of Hematology, 2013
    Co-Authors: Fabienne Huber, Tsogyal D Latshang, Jeroen S. Goede, Konrad E Bloch
    Abstract:

    Alterations in hemoglobin oxygen affinity can be detected by exposing Blood to different PO2 and recording oxygen saturation, a method termed tonometry. It is the gold standard to measure the PO2 associated with 50 % oxygen saturation, the index used to quantify oxygen affinity (P50Tono). P50Tono is used in the evaluation of patients with erythrocytosis suspected to have hemoglobin with abnormal oxygen affinity. Since tonometry is labor intensive and not generally available, we investigated whether accurate estimates of P50 could also be obtained by venous Blood Gas Analysis, co-oximetry, and standard equations (P50Ven). In 50 patients referred for evaluation of erythrocytosis, pH, PO2, and oxygen saturation were measured in venous Blood to estimate P50Ven; P50Tono was measured for comparison. Agreement among P50Ven and P50Tono was evaluated (Bland–Altman Analysis). Mean P50Tono was 25.8 (range 17.4–34.1) mmHg. The mean difference (bias) of P50Tono-P50Ven was 0.5 mmHg; limits of agreement (95 % confidence limits) were −5.2 to +6.1 mmHg. The sensitivity and specificity of P50Ven to identify the 25 patients with P50Tono outside the normal range of 22.9–26.8 mmHg were 5 and 77 %, respectively. We conclude that estimates of P50 based on venous Blood Gas Analysis and standard equations have a low bias compared to tonometry. However, the precision of P50Ven is not sufficiently high to replace P50Tono in the evaluation of individual patients with suspected disturbances of hemoglobin oxygen affinity.

  • Pulmonary function and arterial Blood Gas Analysis.
    2013
    Co-Authors: Christian F. Clarenbach, Oliver Senn, Andreas L. Christ, Manuel Fischler, Marco Maggiorini, Konrad E Bloch
    Abstract:

    Means ±SD. FVC, FEV1, PEF: forced expiratory vital capacity, expiratory volume in 1 sec and peak expiratory flow, respectively; CV: closing volume above residual volume. TLC, RV: total lung capacity and residual volume measured by methane dilution; SNIP: sniff nasal inspiratory pressure; DLCO: carbon monoxide single-breath diffusing capacity in absolute units, in % predicted and in % predicted after adjustment for reduced PIO2.*P

  • does venous Blood Gas Analysis provide accurate estimates of hemoglobin oxygen affinity
    European Respiratory Journal, 2011
    Co-Authors: Fabienne Huber, Tsogyal D Latshang, Jeroen S. Goede, Konrad E Bloch
    Abstract:

    Background: Polycythemia occurs in conditions with chronic hypoxemia including lung and heart disease, polycythemia vera, hemoglobinopathies and in certain neoplasms. Arterial Blood Gas Analysis and assessment of hemoglobin oxygen affinity by the PO2 with oxygen saturation of 50% (P50) are used to evaluate potential causes of secondary polycythemia. We investigated accuracy of a simplified estimation of P50 from venous Blood in comparison to tonometry, the gold standard for measurement of P50. Methods: In 50 patients referred for evaluation of polycythemia pH, PO2 and SO2 were measured in venous Blood (ABL 700 series, Radiometer, Copenhagen) and P50v was derived by standard equations (Severinghaus, J Appl Physiol 1979;46:599). Tonometry was performed to obtain P50t (Hemoxanalyzer, TCS, New Hope, PA). Agreement of P50v and P50t was analyzed. Results: The mean P50t was 25.8 (range 17.4-34.1) mmHg. The mean difference (bias) of P50v and P50t was 0.5 mmHg, the limits of agreement (95% CI) were -5.15 to +6.09 mmHg. The sensitivity and specificity of P50v to identify patients with P50t outside the normal range (23-27 mmHg) were 5 and 77%, respectively. Conclusions: Estimates of P50 based on venous Blood Gas Analysis and standard equations have a low bias compared to tonometry. However, the precision of P50v is not sufficiently high to replace P50t in the evaluation of individual patients with suspected disturbances of hemoglobin oxygen affinity.

Fabienne Huber - One of the best experts on this subject based on the ideXlab platform.

  • does venous Blood Gas Analysis provide accurate estimates of hemoglobin oxygen affinity
    Annals of Hematology, 2013
    Co-Authors: Fabienne Huber, Tsogyal D Latshang, Jeroen S. Goede, Konrad E Bloch
    Abstract:

    Alterations in hemoglobin oxygen affinity can be detected by exposing Blood to different PO2 and recording oxygen saturation, a method termed tonometry. It is the gold standard to measure the PO2 associated with 50 % oxygen saturation, the index used to quantify oxygen affinity (P50Tono). P50Tono is used in the evaluation of patients with erythrocytosis suspected to have hemoglobin with abnormal oxygen affinity. Since tonometry is labor intensive and not generally available, we investigated whether accurate estimates of P50 could also be obtained by venous Blood Gas Analysis, co-oximetry, and standard equations (P50Ven). In 50 patients referred for evaluation of erythrocytosis, pH, PO2, and oxygen saturation were measured in venous Blood to estimate P50Ven; P50Tono was measured for comparison. Agreement among P50Ven and P50Tono was evaluated (Bland–Altman Analysis). Mean P50Tono was 25.8 (range 17.4–34.1) mmHg. The mean difference (bias) of P50Tono-P50Ven was 0.5 mmHg; limits of agreement (95 % confidence limits) were −5.2 to +6.1 mmHg. The sensitivity and specificity of P50Ven to identify the 25 patients with P50Tono outside the normal range of 22.9–26.8 mmHg were 5 and 77 %, respectively. We conclude that estimates of P50 based on venous Blood Gas Analysis and standard equations have a low bias compared to tonometry. However, the precision of P50Ven is not sufficiently high to replace P50Tono in the evaluation of individual patients with suspected disturbances of hemoglobin oxygen affinity.

  • does venous Blood Gas Analysis provide accurate estimates of hemoglobin oxygen affinity
    European Respiratory Journal, 2011
    Co-Authors: Fabienne Huber, Tsogyal D Latshang, Jeroen S. Goede, Konrad E Bloch
    Abstract:

    Background: Polycythemia occurs in conditions with chronic hypoxemia including lung and heart disease, polycythemia vera, hemoglobinopathies and in certain neoplasms. Arterial Blood Gas Analysis and assessment of hemoglobin oxygen affinity by the PO2 with oxygen saturation of 50% (P50) are used to evaluate potential causes of secondary polycythemia. We investigated accuracy of a simplified estimation of P50 from venous Blood in comparison to tonometry, the gold standard for measurement of P50. Methods: In 50 patients referred for evaluation of polycythemia pH, PO2 and SO2 were measured in venous Blood (ABL 700 series, Radiometer, Copenhagen) and P50v was derived by standard equations (Severinghaus, J Appl Physiol 1979;46:599). Tonometry was performed to obtain P50t (Hemoxanalyzer, TCS, New Hope, PA). Agreement of P50v and P50t was analyzed. Results: The mean P50t was 25.8 (range 17.4-34.1) mmHg. The mean difference (bias) of P50v and P50t was 0.5 mmHg, the limits of agreement (95% CI) were -5.15 to +6.09 mmHg. The sensitivity and specificity of P50v to identify patients with P50t outside the normal range (23-27 mmHg) were 5 and 77%, respectively. Conclusions: Estimates of P50 based on venous Blood Gas Analysis and standard equations have a low bias compared to tonometry. However, the precision of P50v is not sufficiently high to replace P50t in the evaluation of individual patients with suspected disturbances of hemoglobin oxygen affinity.

Richard E Moon - One of the best experts on this subject based on the ideXlab platform.

  • arterial Blood Gas Analysis in breath hold divers at depth
    Frontiers in Physiology, 2018
    Co-Authors: Gerardo Bosco, Alex Rizzato, Luca Martani, Simone Schiavo, Ennio Talamonti, Giacomo Garetto, Matteo Paganini, Enrico M Camporesi, Richard E Moon
    Abstract:

    The present study aimed to evaluate the partial pressure of arterial Blood Gases on breath-hold divers performing a submersion at 40 m. Eight breath-hold divers were enrolled for the trials held at “Y-40 THE DEEP JOY” pool (Montegrotto Terme, Padova, Italy). Prior to submersion, an arterial cannula in the radial artery of the non-dominant limb was positioned. All divers performed a sled-assisted breath-hold dive to 40 meters. Three Blood samplings occurred: at 10 minutes prior to submersion, at 40 meters depth, and within 2 minutes after diver’s surfacing and after resuming normal ventilation. Blood samples were analyzed immediately on site. Six subjects completed the experiment, without diving-related problems. The theoretically predicted hyperoxia at the bottom was observed in 4 divers out of 6, while the other 2 experienced a reduction in the partial pressure of oxygen (paO2) at the bottom. There were no significant increases in arterial partial pressure of carbon dioxide (paCO2) at the end of descent in 4 of 6 divers, while in 2 divers paCO2 decreased. Arterial mean pH and mean bicarbonate (HCO3-) levels exhibited minor changes. There was a statistically significant increase in mean arterial lactate level after the exercise. Ours was the first attempt to verify real changes in Blood Gases at a depth of 40 m during a breath-hold descent in free-divers. We demonstrated that, at depth, relative hypoxemia can occur, presumably caused by lung compression. Also, hypercapnia exists at depth, to a lesser degree than would be expected from calculations, presumably because of pre-dive hyperventilation and carbon dioxide distribution in Blood and tissues.

  • Arterial Blood Gas Analysis in Breath-Hold Divers at Depth
    Frontiers Media S.A., 2018
    Co-Authors: Gerardo Bosco, Alex Rizzato, Luca Martani, Simone Schiavo, Ennio Talamonti, Giacomo Garetto, Matteo Paganini, Enrico M Camporesi, Richard E Moon
    Abstract:

    The present study aimed to evaluate the partial pressure of arterial Blood Gases in breath-hold divers performing a submersion at 40 m. Eight breath-hold divers were enrolled for the trials held at “Y-40 THE DEEP JOY” pool (Montegrotto Terme, Padova, Italy). Prior to submersion, an arterial cannula in the radial artery of the non-dominant limb was positioned. All divers performed a sled-assisted breath-hold dive to 40 m. Three Blood samplings occurred: at 10 min prior to submersion, at 40 m depth, and within 2 min after diver’s surfacing and after resuming normal ventilation. Blood samples were analyzed immediately on site. Six subjects completed the experiment, without diving-related problems. The theoretically predicted hyperoxia at the bottom was observed in 4 divers out of 6, while the other 2 experienced a reduction in the partial pressure of oxygen (paO2) at the bottom. There were no significant increases in arterial partial pressure of carbon dioxide (paCO2) at the end of descent in 4 of 6 divers, while in 2 divers paCO2 decreased. Arterial mean pH and mean bicarbonate (HCO3−) levels exhibited minor changes. There was a statistically significant increase in mean arterial lactate level after the exercise. Ours was the first attempt to verify real changes in Blood Gases at a depth of 40 m during a breath-hold descent in free-divers. We demonstrated that, at depth, relative hypoxemia can occur, presumably caused by lung compression. Also, hypercapnia exists at depth, to a lesser degree than would be expected from calculations, presumably because of pre-dive hyperventilation and carbon dioxide distribution in Blood and tissues

Jeroen S. Goede - One of the best experts on this subject based on the ideXlab platform.

  • does venous Blood Gas Analysis provide accurate estimates of hemoglobin oxygen affinity
    Annals of Hematology, 2013
    Co-Authors: Fabienne Huber, Tsogyal D Latshang, Jeroen S. Goede, Konrad E Bloch
    Abstract:

    Alterations in hemoglobin oxygen affinity can be detected by exposing Blood to different PO2 and recording oxygen saturation, a method termed tonometry. It is the gold standard to measure the PO2 associated with 50 % oxygen saturation, the index used to quantify oxygen affinity (P50Tono). P50Tono is used in the evaluation of patients with erythrocytosis suspected to have hemoglobin with abnormal oxygen affinity. Since tonometry is labor intensive and not generally available, we investigated whether accurate estimates of P50 could also be obtained by venous Blood Gas Analysis, co-oximetry, and standard equations (P50Ven). In 50 patients referred for evaluation of erythrocytosis, pH, PO2, and oxygen saturation were measured in venous Blood to estimate P50Ven; P50Tono was measured for comparison. Agreement among P50Ven and P50Tono was evaluated (Bland–Altman Analysis). Mean P50Tono was 25.8 (range 17.4–34.1) mmHg. The mean difference (bias) of P50Tono-P50Ven was 0.5 mmHg; limits of agreement (95 % confidence limits) were −5.2 to +6.1 mmHg. The sensitivity and specificity of P50Ven to identify the 25 patients with P50Tono outside the normal range of 22.9–26.8 mmHg were 5 and 77 %, respectively. We conclude that estimates of P50 based on venous Blood Gas Analysis and standard equations have a low bias compared to tonometry. However, the precision of P50Ven is not sufficiently high to replace P50Tono in the evaluation of individual patients with suspected disturbances of hemoglobin oxygen affinity.

  • does venous Blood Gas Analysis provide accurate estimates of hemoglobin oxygen affinity
    European Respiratory Journal, 2011
    Co-Authors: Fabienne Huber, Tsogyal D Latshang, Jeroen S. Goede, Konrad E Bloch
    Abstract:

    Background: Polycythemia occurs in conditions with chronic hypoxemia including lung and heart disease, polycythemia vera, hemoglobinopathies and in certain neoplasms. Arterial Blood Gas Analysis and assessment of hemoglobin oxygen affinity by the PO2 with oxygen saturation of 50% (P50) are used to evaluate potential causes of secondary polycythemia. We investigated accuracy of a simplified estimation of P50 from venous Blood in comparison to tonometry, the gold standard for measurement of P50. Methods: In 50 patients referred for evaluation of polycythemia pH, PO2 and SO2 were measured in venous Blood (ABL 700 series, Radiometer, Copenhagen) and P50v was derived by standard equations (Severinghaus, J Appl Physiol 1979;46:599). Tonometry was performed to obtain P50t (Hemoxanalyzer, TCS, New Hope, PA). Agreement of P50v and P50t was analyzed. Results: The mean P50t was 25.8 (range 17.4-34.1) mmHg. The mean difference (bias) of P50v and P50t was 0.5 mmHg, the limits of agreement (95% CI) were -5.15 to +6.09 mmHg. The sensitivity and specificity of P50v to identify patients with P50t outside the normal range (23-27 mmHg) were 5 and 77%, respectively. Conclusions: Estimates of P50 based on venous Blood Gas Analysis and standard equations have a low bias compared to tonometry. However, the precision of P50v is not sufficiently high to replace P50t in the evaluation of individual patients with suspected disturbances of hemoglobin oxygen affinity.

Tsogyal D Latshang - One of the best experts on this subject based on the ideXlab platform.

  • does venous Blood Gas Analysis provide accurate estimates of hemoglobin oxygen affinity
    Annals of Hematology, 2013
    Co-Authors: Fabienne Huber, Tsogyal D Latshang, Jeroen S. Goede, Konrad E Bloch
    Abstract:

    Alterations in hemoglobin oxygen affinity can be detected by exposing Blood to different PO2 and recording oxygen saturation, a method termed tonometry. It is the gold standard to measure the PO2 associated with 50 % oxygen saturation, the index used to quantify oxygen affinity (P50Tono). P50Tono is used in the evaluation of patients with erythrocytosis suspected to have hemoglobin with abnormal oxygen affinity. Since tonometry is labor intensive and not generally available, we investigated whether accurate estimates of P50 could also be obtained by venous Blood Gas Analysis, co-oximetry, and standard equations (P50Ven). In 50 patients referred for evaluation of erythrocytosis, pH, PO2, and oxygen saturation were measured in venous Blood to estimate P50Ven; P50Tono was measured for comparison. Agreement among P50Ven and P50Tono was evaluated (Bland–Altman Analysis). Mean P50Tono was 25.8 (range 17.4–34.1) mmHg. The mean difference (bias) of P50Tono-P50Ven was 0.5 mmHg; limits of agreement (95 % confidence limits) were −5.2 to +6.1 mmHg. The sensitivity and specificity of P50Ven to identify the 25 patients with P50Tono outside the normal range of 22.9–26.8 mmHg were 5 and 77 %, respectively. We conclude that estimates of P50 based on venous Blood Gas Analysis and standard equations have a low bias compared to tonometry. However, the precision of P50Ven is not sufficiently high to replace P50Tono in the evaluation of individual patients with suspected disturbances of hemoglobin oxygen affinity.

  • does venous Blood Gas Analysis provide accurate estimates of hemoglobin oxygen affinity
    European Respiratory Journal, 2011
    Co-Authors: Fabienne Huber, Tsogyal D Latshang, Jeroen S. Goede, Konrad E Bloch
    Abstract:

    Background: Polycythemia occurs in conditions with chronic hypoxemia including lung and heart disease, polycythemia vera, hemoglobinopathies and in certain neoplasms. Arterial Blood Gas Analysis and assessment of hemoglobin oxygen affinity by the PO2 with oxygen saturation of 50% (P50) are used to evaluate potential causes of secondary polycythemia. We investigated accuracy of a simplified estimation of P50 from venous Blood in comparison to tonometry, the gold standard for measurement of P50. Methods: In 50 patients referred for evaluation of polycythemia pH, PO2 and SO2 were measured in venous Blood (ABL 700 series, Radiometer, Copenhagen) and P50v was derived by standard equations (Severinghaus, J Appl Physiol 1979;46:599). Tonometry was performed to obtain P50t (Hemoxanalyzer, TCS, New Hope, PA). Agreement of P50v and P50t was analyzed. Results: The mean P50t was 25.8 (range 17.4-34.1) mmHg. The mean difference (bias) of P50v and P50t was 0.5 mmHg, the limits of agreement (95% CI) were -5.15 to +6.09 mmHg. The sensitivity and specificity of P50v to identify patients with P50t outside the normal range (23-27 mmHg) were 5 and 77%, respectively. Conclusions: Estimates of P50 based on venous Blood Gas Analysis and standard equations have a low bias compared to tonometry. However, the precision of P50v is not sufficiently high to replace P50t in the evaluation of individual patients with suspected disturbances of hemoglobin oxygen affinity.