VASOPRESSIN SERUM LEVELS AND DISORDERS OF SODIUM AND WATER BALANCE IN PATIENTS WITH SEVERE BRAIN INJURY

ABSTRACT- Background: Disorders of water and sodium balance are frequently seen in patients with se-vere brain injury (SBI), and may worsen their prognosis. Purpose: To evaluate vasopressin (AVP) serum lev-els and sodium and water balance disorders during the first week post-injury in patients with SBI. Method: Thirty-six adult patients with SBI (admission Glasgow Coma Scale score ≤ 8) and an estimated time of injury ≤ 72 hours were prospectively studied. Clinical and laboratory data were recorded and AVP was measured in venous blood samples collected on the 1st, 2nd, 3rd and 5th days following inclusion. Results: AVP serum lev-els remained within the normal range in SBI patients (either traumatic or non-traumatic), although tended to be greater in non-survivor than in survivor patients (p=0.025 at 3rd day). In-hospital mortality was 43% (15/36), and serum sodium and plasma osmolality variabilities were greater in non-survivor than in survivor patients during the observation period (p<0.001). Conclusion: AVP serum levels remained within the nor-mal range values in these SBI patients, but those who died have shown higher incidence of abnormal sodi-um and water balance during the first week post-injury. KEY WORDS: vasopressin, severe brain injury, hyponatremia, hypernatremia. Níveis séricos de vasopressina e distúrbios de sódio e água em pacientes com lesão cerebral grave RESUMO- Antecedentes: Desordens do balanço de água e sódio são frequentemente vistas em pacientes co