A patient who is undergoing an' elective opera-tion under spinal anesthesia develops a blood pressure of 70/40 mmHg. There is no evidence of hemorrhage or sepsis. Appropriate initial therapy should consist of administration of
|A||2 L of saline|
|D||An alpharnimetic drug|
a. Hypotension may occur as a result of sympatholytic-induced vasodilation and bradycardia. It may be more severe in hypovolemic patients or in those with preexisting cardiac dysfunction.
b. Treatment includes volume resuscitation with crystalloid, vasopressors (epinephrine, 5 to 10 µg intravenously or phenylephrine hydrochloride, 50 to 100 µg intravenously), and positive chronotropic drugs.
c. It is advisable to administer 500 to 1,000 mL of crystalloid prior to spinal block to avoid hypotension due to spinal anesthesia.
d. Administration of vasopressor drugs like ephedrine, phenylephrine increase peripheral vascular resistance and restores blood pressure back to normal.
e. Patients who have neurogenic shock that is secondary to CNS or spinal cord injury may incur extracellular fluid losses and therefore require haemodynamic monitoring.