Cardiovascular response to spinal anaesthesia in elderly men: effects of head‐up tilt and dihydroergotamine administration

In nine elderly (mean age 60, rang 42-74 years) cardiovascular pressures and cardiac output have been measured by catheterization of the pulmonary and brachial artery during spinal anaesthesia without and with dihydroergotamine (DHE) and during an added slight head-up (10-15 degrees). Spinal anaesthesia lowered arterial pressure and also stroke volume. After DHE arterial pressures as well as stroke volume were normalized. Tilting before spinal anaesthesia lowered stroke volume but arterial pressures were maintained. During spinal anaesthesia, tilting lowered arterial pressures as well as filling pressures of the heart. After administration of DHE during spinal anaesthesia the pressures were unaffected by tilting. It is concluded that in elderly men, unlike the young men previously studied, spinal anaesthesia decreases arterial blood pressures by a combination of reduced peripheral resistance and decreased stroke volume. The decreases in stroke volume and cardiac output were most pronounced in those patients with a reduced blood volume. DHE also prevents arterial pressure fall with head-up tilt during spinal anaesthesia.