Lung recruitment maneuvers markedly reduced cardiac output and left ventricular end-diastolic areas in hemodynamically stable patients following cardiac surgery.
In patients ventilated after cardiac surgery: (1) PEEP increased lung volume but not PaO2, (2) a lung recruitment maneuver without subsequent PEEP had no sustained effect, and (3) both a lung recruitment maneuver and PEEP were needed to increase and maintain the increased lung volume and PaO2.
Background-In patients with ischemic heart disease, high thoracic epidural analgesia (TEA) has been proposed to improve abnormalities of coronary function by inhibiting cardiac sympathetic tone. We evaluated the effect of TEA on myocardial blood flow in patients with ischemic heart disease. Methods and Results-Twenty male patients with multivessel ischemic heart disease were studied. An epidural catheter was inserted between the second and third thoracic vertebral interspace (Th2 to Th3). Analgesia was induced by epidural injection of bupivacaine 0.5%, and a sensory block from the sixth cervical (C6 to C7) to Th10 (Th8 to Th11) vertebral interspace was achieved. Myocardial blood flow was measured with dynamic 13 N-ammonia PET with and without TEA at rest, during pharmacological vasodilation with dipyridamole, and during sympathetic stimulation with the cold pressor test. Myocardial blood flow during dipyridamole increased similarly, regardless of TEA, in all regions except in myocardium subtended by collateral arteries in which blood flow increased more with than without TEA (PϽ0.05). Without TEA, myocardial blood flow during the cold pressor test remained unchanged compared with myocardial blood flow at rest. In contrast, with TEA, myocardial blood flow increased in all vascular territories. Coronary vascular resistance increased during the cold pressor test without TEA, whereas with TEA, coronary resistance decreased in myocardium subtended by nonstenotic and stenotic coronary vessels and remained unchanged in myocardium subtended by occluded vessels. Conclusions-In patients with multivessel ischemic heart disease, TEA partly normalizes the myocardial blood flow response to sympathetic stimulation.
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