The structure of surgery of pituitary adenomas has been fundamentally changed over the past decade. The transnasal transsphenoidal approach is currently used to resect more than 95% of adenomas. The wide use of endoscopy has changed the need for perioperative control of intracranial pressure. While controlled intracranial hypertension was previously used during microscopically controlled transnasal surgery to bring the suprasellar capsule and tumor remnants to the field of vision, endoscopically controlled tumor resection implies that controlled intracranial hypotension is required to achieve complete spreading of the suprasellar capsule. External lumbar drains inserted at least for the entire surgery duration are conventionally used to control intracranial pressure. We present the results of the study proving the effectiveness and safety of the HyperHAES hypertonic isooncotic plasma substitute in achieving stable intracranial hypotension according to a large body of clinical data. Our findings give grounds for claiming that the use of the HyperHAES hypertonic isooncotic plasma substitute during the standard adenomectomy allows one to abandon the use of invasive external lumbar drainage, while the surgery quality and risks remain at the same level.