Blood Pressure Increase during Oxygen Supplementation in Chronic Kidney Disease Patients Is Mediated by Vasoconstriction Independent of Baroreflex Function

Figures

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  Figure 1. Normobaric oxygen supplementation protocol. Room air (RA) and oxygen at different concentrations (21, 50, or 100%) were provided for 15 min each. Measurements were performed at atmospheric pressure, i.e., 1 atmosphere absolute (ATA). At atmospheric pressure a partial oxygen pressure (ppO2) of 1.0 ATA is reached, when 100% oxygen is provided.

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  Figure 2. Hyperbaric oxygen supplementation protocol. Normobaric and hyperbaric room air (RA) and hyperbaric oxygen (100%) were provided for 15 min each. Measurements were performed at atmospheric pressure (1 ATA) and under hyperbaric conditions (2.4 ATA). At atmospheric pressure a partial oxygen pressure (ppO2) of 1.0 ATA was reached, when 100% oxygen was provided. During hyperbaric oxygen supplementation this further increased 2.4-fold, to 2.4 ATA.

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  Figure 3. Hemodynamic response to normobaric oxygen supplementation, for the patient (solid bars) and the young healthy controls (open bars). All graphs depict absolute mean ± SD at each condition: room air (RA), 21% oxygen over a non-rebreathing mask (ppO2 0.21 ATA), 50% oxygen (ppO2 0.5 ATA), and 100% oxygen (ppO2 1.0 ATA). Averages over the last minute of each condition for: (A) systolic blood pressure; (B) diastolic blood pressure; (C) mean arterial pressure (MAP); (D) pulse pressure (PP); (E) heart rate (HR); (F) systemic vascular resistance (SVR); (G) cardiac output (CO); (H) baroreflex sensitivity (xBRS). Designation of significant responses to oxygen supplementation in patients * and in controls†.

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  Figure 4. Hemodynamic response to hyperbaric oxygen supplementation. All graphs depict absolute mean ± SD at each condition: room air (RA), hyperbaric RA (ppO2 0.5 ATA), and hyperbaric oxygen (ppO2 2.4 ATA). Averages over the last minute of blood pressure registration at each condition of: (A) systolic blood pressure; (B) diastolic blood pressure; (C) mean arterial pressure (MAP); (D) pulse pressure (PP); (E) heart rate (HR); (F) systemic vascular resistance (SVR); (G) cardiac output (CO); (H) baroreflex sensitivity (xBRS).