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Hydroxyethyl starch pretreatment in bacteremic sheep
H J Lübbesmeyer1, D J Dehring, J L Theissen
1Department of Anesthesiology, University of Texas Medical Branch 77550.
Abstract:
Live bacteria were infused in a chronic ovine lung lymph model to determine if a preceding infusion of the colloid, hydroxyethyl starch (HES), exaggerated the cardiopulmonary dysfunction or impaired removal of bacteria by macrophages in the pulmonary circulation. HES was infused (3 mL/kg/hr; n = 6) from 24 to 12 hr before the bacteria and decreased plasma protein content and increased pulmonary lymph to plasma protein concentration because of its oncotic properties. Ringer's lactate (2 mL/kg/hr) was given after stopping HES and also to the control group (n = 6). Infusion of live Ps. aeruginosa (2.5 x 10(8) Ps./min for approximately 30 min) induced equivalent pulmonary hypertension, increased pulmonary microvascular permeability, and cardiovascular depression in the two groups. The removal of bacteria in the lungs was not affected, indicating that this measurement of the function of the mononuclear phagocytic system was not impaired by the preceding HES.
Insights
Hydroxyethyl starch (HES) did not worsen lung injury or impair bacterial clearance in sheep. This study found HES infusion did not affect the removal of Pseudomonas aeruginosa by the mononuclear phagocytic system.
Area of Science:
- Cardiopulmonary physiology
- Infectious disease research
- Pharmacology
Background:
- Hydroxyethyl starch (HES) is a colloid used for fluid resuscitation.
- Potential adverse effects of HES on cardiopulmonary function and immune response require investigation.
- The ovine lung lymph model allows for detailed study of pulmonary circulation and inflammation.
Purpose of the Study:
- To investigate if HES infusion exacerbates cardiopulmonary dysfunction following bacterial challenge.
- To determine if HES impairs the clearance of bacteria by pulmonary macrophages.
- To assess the impact of HES on the mononuclear phagocytic system's function in the lungs.
Main Methods:
- Utilized a chronic ovine lung lymph model.
- Administered HES or Ringer's lactate to sheep.
- Infused live Pseudomonas aeruginosa to induce pulmonary infection.
- Monitored cardiopulmonary parameters and measured bacterial removal by lung macrophages.
Main Results:
- HES infusion decreased plasma protein and increased lymph to plasma protein concentration due to oncotic properties.
- Bacterial infusion induced similar pulmonary hypertension, increased microvascular permeability, and cardiovascular depression in both HES-treated and control groups.
- Bacterial removal in the lungs was unaffected by preceding HES infusion.
Conclusions:
- Preceding HES infusion did not exaggerate cardiopulmonary dysfunction in this ovine model.
- HES did not impair the removal of Pseudomonas aeruginosa by the pulmonary mononuclear phagocytic system.
- The function of the mononuclear phagocytic system in bacterial clearance was not compromised by HES.