Hypothalamic injury as a cause of refractory hypotension after sellar region tumor surgery

Fluid-resistant arterial hypotension can result in hypoperfusion of the brain and other organs. Well-known causes of arterial hypotension in neurosurgical practice include cardiac failure, septic shock, adrenal insufficiency, brainstem, and cervical spinal cord damage. Fluid-resistant arterial hypotension can occur in patients with brain edema without damage to brainstem when hypothalamic nuclei suffer. This phenomenon is not a well-documented cause of hypotension.

We prospectively investigated 15 cases with clinical syndrome of arterial hypotension in patients following surgery for sellar region tumors. These cases were taken from 1005 patients operated between May 2003 and December 2005. Pulmonary artery catheter was used to investigate hemodynamic profile.

The mechanism of arterial hypotension consisted of decrease of vascular tone (SVRI was 1503 +/- 624 dyn x s x cm(5) x m(2)) and relative hypovolemia (CVP: 4.5 +/- 2.6 torr, PAWP: 7.4 +/- 3.5 torr). In all cases arterial hypotension was corrected with phenylephrine after failure to respond to fluid resuscitation alone. Fluid balance was positive over the next 72 h. Twenty-seven percent of patients had transitory thyroid insufficiency. In these situations dopamine was administrated as symptomatic therapy and dose of thyroid hormone was increased. Mortality was 53%.

Hypothalamic damage can result in life-threatening vasodilatory arterial hypotension after sellar region tumor surgery. beta-Sympatomimetics are indicated in cases with thyroid insufficiency.