JSAL Anesthesia Practice Test

Maintaining myocardial oxygen balance during anesthesia hinges on keeping oxygen delivery high and demand under control. Arterial oxygen content (CaO2) combines how much oxygen is carried by hemoglobin and how much is dissolved in plasma; together with cardiac output, this determines oxygen delivery to the heart. Preserve coronary perfusion by keeping blood pressure adequate, especially diastolic pressure, since coronary flow occurs mainly in diastole. At the same time, avoid conditions that raise myocardial oxygen consumption, such as tachycardia and excessive afterload. The best approach is to ensure adequate oxygen content and perfusion, while carefully using fluids and vasopressors to maintain coronary perfusion without driving up oxygen demand. This contrasts with letting blood pressure drop or heart rate accelerate unchecked, which would worsen ischemia, or indiscriminately giving fluids, which can cause overload without improving perfusion if cardiac status cannot tolerate it.