Elevation of the end-tidal partial pressure of CO₂ (P_ETco₂) increases cerebral and myocardial blood flow (MBF), suggesting that it may be a suitable alternative to pharmacologic stress or exercise for myocardial perfusion imaging. The purpose of this study was to document the pharmacodynamics of CO₂ for MBF using prospective end-tidal targeting to precisely control arterial Pco₂ and PET to measure the outcome variable, MBF. Methods: Ten healthy men underwent serial ⁸²Rb PET/CT imaging. Imaging was performed at rest and during 6-min hypercapnic plateaus (baseline; P_ETco₂ at 50, 55, and 60 mm Hg; repeat of P_ETco₂ at 60 mm Hg; and repeat of baseline). MBF was measured using ⁸²Rb injected 3 min after the beginning of hypercapnia and a 1-tissue-compartment model with flow-dependent extraction correction. Results were compared with those obtained during an adenosine stress test (140 μg/kg/min). Results: Baseline P_ETco₂ was 38.9 ± 0.8 (mean ± SD) mm Hg (range, 35–43 mm Hg). All P_ETco₂ targets were sustained, with SDs of less than 1.5 mm Hg. Heart rate, systolic blood pressure, rate × pressure product, and respiratory frequency increased with progressive hypercapnia. MBF increased significantly at each level of hypercapnia to 1.92-fold over baseline (0.86 ± 0.24 vs. 0.45 ± 0.08 mL/min/g; P = 0.002) at a P_ETco₂ of 60 mm Hg. MBF after the administration of adenosine was significantly greater than that with the maximal hypercapnic stimulus (2.00 vs. 0.86 mL/min/g; P < 0.0001). Conclusion: To our knowledge, this study is the first to assess the response of MBF to different levels of hypercapnia in healthy humans with PET. MBF increased with increasing levels of hypercapnia; MBF at a P_ETco₂ of 60 mm Hg was double that at baseline.

潮气末CO ₂（P _ET co ₂）的升高会增加脑和心肌的血流量（MBF），这表明它可能是替代药理应激或运动进行心肌灌注显像的一种方法。这项研究的目的是使用预期的潮气末靶向技术精确控制动脉P co ₂和PET来测量结果变量MBF ，从而记录CO ₂对MBF的药效学。方法：十名健康男性接受了⁸² Rb PET / CT系列影像学检查。成像在休息和高碳酸血症高原6分钟期间进行（基线； P _ET co ₂在50、55和60毫米汞柱下; 在60 mm Hg重复P _ET co ₂；并重复基线）。在高碳酸血症开始后3分钟注射⁸² Rb并使用具有流量依赖性提取校正的1组织隔室模型测量MBF 。将结果与在腺苷压力测试（140μg/ kg / min）中获得的结果进行比较。结果：基线P _ET co ₂为38.9±0.8（平均±SD）mm Hg（范围35–43 mm Hg）。全部P _ET co ₂目标得以维持，SD低于1.5毫米汞柱。随着进行性高碳酸血症，心率，收缩压，心率×压力乘积和呼吸频率增加。在60 mm Hg的P _ET co ₂下，每个高碳酸血症水平的MBF显着增加至基线的1.92倍（0.86±0.24对0.45±0.08 mL / min / g；P = 0.002）。给予腺苷后的MBF明显大于最大高碳酸血症刺激后的MBF（2.00 vs. 0.86 mL / min / g；P <0.0001）。结论：据我们所知，该研究是第一个评估健康人PET中MBF对不同水平的高碳酸血症的反应的方法。MBF随着高碳酸血症水平的增加而增加；MBF在P_ET co ₂为60 mm Hg，是基线时的两倍。