[Endocrine reactions during acute normovolemic hemodilution]

Area of Science:

• Anesthesiology
• Endocrinology
• Surgical Research

Background:

• Orthopedic surgery patients undergoing hip replacement often experience significant physiological stress.
• Epidural anesthesia is used to manage pain and stress during these procedures.
• Acute normovolemic hemodilution (ANH) is a technique that may alter physiological responses.

Purpose of the Study:

• To investigate the influence of ANH on endocrine parameters in patients undergoing hip replacement surgery under epidural anesthesia.
• To assess the impact of ANH on hemodynamic and stress hormone levels during the perioperative period.

Main Methods:

• Twenty patients were randomized into an ANH group (receiving fluid substitution) and a control group.
• Measurements included mean arterial pressure (MAP), heart rate (HR), and plasma levels of adrenaline, noradrenaline, ADH, ACTH, and cortisol.
• Biochemical markers like glucose, lactate, and free glycerol were also analyzed.

Main Results:

• The ANH group exhibited significantly higher MAP with less pronounced intraoperative decrease.
• Adrenaline, ACTH, and cortisol levels remained within normal ranges in both groups, showing no specific ANH influence.
• Noradrenaline levels were elevated in both groups, with a slight increase during ANH, while ADH was higher in the control group.

Conclusions:

• ANH demonstrated no adverse effects on the endocrine stress response during orthopedic surgery with epidural anesthesia.
• The observed sympatho-adrenergic reactions were moderate and well-tolerated, even in patients with cardiovascular conditions.
• Perioperative endocrine parameter changes suggest adequate stress protection provided by epidural anesthesia, with or without ANH.