HEMODYNAMIC-RESPONSE AND CHANGE IN ORGAN BLOOD-VOLUME DURING SPINAL-ANESTHESIA IN ELDERLY MEN WITH CARDIAC DISEASE

Aging and disease may make the elderly patient with cardiac disease pa rticularly susceptible to hypotension during spinal anesthesia. We stu died 15 men, 59-80 y old, with histories of prior myocardial infarctio n (n = 9), congestive heart failure (n = 2), and/or stable myocardial ischemia (n = 11) given spinal anesthesia with 50 mg Lidocaine in dext rose. Technetium-99m-labeled red blood cell imaging estimated left ven tricular ejection fraction (EF) and changes in blood volume in the abd ominal organs and legs. Arterial and pulmonary artery catheters provid ed hemodynamic measurements. Sensory block averaged T4 (range T1-10). Mean arterial pressure decreased 33% +/- 15% (SD) (P < 0.001), seconda ry to decreases in vascular resistance (SVR), -26% +/- 13% (P < 0.001) and cardiac output, -10% +/- 16% (P = 0.03). EF increased from 53% +/ - 11% to 58% +/- 14% (P ( 0.001) while left ventricular end-diastolic volume (LVEDV) decreased (-19% +/- 9%, P < 0.001). Blood volume increa sed in the legs (6% +/- 6%, P = 0.006), kidneys (10% +/- 9%, P < 0.001 ), and mesentery (7% +/- 5%, P 0.001) but not in the liver or spleen. Cardiac function was well maintained. We concluded that the primary me chanism of hypotension was a decrease in SVR, not cardiac output, desp ite the decrease in LVEDV.