Thoracic peridural block in experimental endotoxin shock

Area of Science:

• Anesthesiology
• Critical Care Medicine
• Physiology

Background:

• Endotoxin shock triggers significant metabolic and hemodynamic disturbances.
• Sympathetic nervous system activation plays a crucial role in the pathophysiology of endotoxin shock.
• Understanding interventions that modulate these responses is vital for improving patient outcomes.

Purpose of the Study:

• To investigate the effects of thoracic peridural block (PDB) on metabolic and hemodynamic changes during endotoxin shock in rabbits.
• To assess the impact of PDB on sympathetic response, glucose metabolism, and circulatory parameters.
• To determine if PDB influences mortality in this animal model of shock.

Main Methods:

• Rabbits subjected to endotoxin shock received intermittent bupivacaine via a thoracic peridural catheter for sympathetic blockade.
• Metabolic markers (plasma glucose, lactate, glycerol) and hemodynamic parameters (mean arterial pressure, cardiac output) were monitored.
• Glucose clearance was assessed using plasma half-life measurements after intravenous glucose injection.
• Mortality rates were recorded at 24 hours.

Main Results:

• PDB prevented the endotoxin-induced increase in plasma glucose, lactate, and free glycerol.
• Animals with PDB exhibited accelerated glucose clearance.
• PDB led to reduced mean arterial pressure and total peripheral resistance, indicating peripheral vasodilatation.
• PDB did not significantly alter right ventricular pressure, cardiac output, O2 consumption, or 24-hour mortality.

Conclusions:

• Thoracic PDB effectively blocks the sympathetic response in endotoxin shock.
• PDB alters metabolic disturbances by inhibiting glycogenolytic and lipolytic responses.
• Despite metabolic improvements, PDB did not significantly reduce mortality in this rabbit model of endotoxin shock.