Spahn D R, Smith L R, Veronee C D, Hu W C, McRae R L, Leone B J
Department of Anesthesiology, Duke University Medical Center, Durham, North Carolina 27710.
Anesth Analg. 1992 Jan;74(1):14-25. doi: 10.1213/00000539-199201000-00004.
Increased myocardial oxygen demand, induced by increased heart rate, may cause myocardial ischemia in the presence of significant coronary artery disease. Alterations in anesthetic depth or technique might put at risk or protect myocardium with compromised blood flow. In 20 dogs with critical left anterior descending coronary artery (LAD) stenosis, atrial pacing rates from 100 to 160 beats/min were achieved, with end-tidal halothane 0.7% (LowH) and 1.1% (HighH), end-tidal isoflurane 1.1% (LowI) and 1.5% (HighI), as well as with continuous fentanyl plus midazolam (FM) infusion anesthesia. Despite significantly different mean arterial and coronary perfusion pressures, rate-pressure product, and left ventricular dP/dtmax, the pacing rate at which systolic shortening decreased below the lower limit of the physiologic response, indicating regional dysfunction, was the same in all investigated anesthesia conditions (LowH: 127 +/- 4 beats/min; HighH: 128 +/- 5 beats/min; LowI: 125 +/- 4 beats/min; HighI: 122 +/- 5 beats/min; FM: 124 +/- 4 beats/min [mean +/- SEM], P greater than 0.05). None of the investigated anesthesia conditions either increased ischemia tolerance or showed a detrimental effect on myocardium with compromised coronary blood flow.
心率增加所诱导的心肌需氧量增加，在存在显著冠状动脉疾病的情况下可能导致心肌缺血。麻醉深度或技术的改变可能会使血流受损的心肌面临风险或起到保护作用。在20只患有严重左前降支冠状动脉（LAD）狭窄的犬中，实现了100至160次/分钟的心房起搏率，采用0.7%（低氟烷组）和1.1%（高氟烷组）的呼气末氟烷、1.1%（低异氟烷组）和1.5%（高异氟烷组）的呼气末异氟烷，以及持续输注芬太尼加咪达唑仑（FM组）进行麻醉。尽管平均动脉压、冠状动脉灌注压、心率与收缩压乘积以及左心室dP/dtmax存在显著差异，但在所有研究的麻醉条件下，收缩期缩短降至生理反应下限以下（表明局部功能障碍）时的起搏率是相同的（低氟烷组：127±4次/分钟；高氟烷组：128±5次/分钟；低异氟烷组：125±4次/分钟；高异氟烷组：122±5次/分钟；FM组：124±4次/分钟[平均值±标准误]，P>0.05）。所研究的麻醉条件均未增加缺血耐受性，也未对冠状动脉血流受损的心肌产生有害影响。
