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[Pulmonary reaction after protamine reversal of heparin in goats and rabbits]
T Horiguchi1, K Enzan, H Mitsuhata
1Department of Anesthesiology, Akita University School of Medicine.
Abstract:
Protamine reversal of heparin is often associated with severe hemodynamic side-effects, including pulmonary hypertension in cardiovascular surgery. However, the precise mechanism of this transient pulmonary hypertension is not clear. Recently, it was reported that pulmonary intravascular macrophages (PIM) react avidly with and phagocytize various foreign particles (liposome, latex, red cells). Sheep, goat and pig have a large population of PIM, but rabbit, rat and human have few. To investigate whether the pulmonary reaction after protamine reversal is related to PIM, we compared the pulmonary reaction after protamine reversal between goats and rabbits. We also studied it in patients for cardiac surgery. Protamine sulphate (2 mg.kg-1) was injected in 2.5 min into femoral artery at five min after heparin sodium (200 IU.kg-1) injection in goats and rabbits. Mean pulmonary arterial and peak airway pressures increased significantly after protamine reversal in goat. On the other hand, in rabbit and human, mean pulmonary arterial and peak airway pressures showed no significant changes. Goat was far more sensitive to protamine reversal than rabbit and human. We conclude that PIM may be the main cause of the pulmonary reaction after protamine reversal.
Insights
Pulmonary intravascular macrophages (PIM) may cause severe pulmonary hypertension after protamine reversal of heparin. Goats, with many PIM, showed significant reactions, unlike rabbits and humans with few PIM.
Area of Science:
- Cardiovascular Physiology
- Immunology
- Pharmacology
Context:
- Protamine reversal of heparin during cardiovascular surgery can cause severe hemodynamic side effects, notably pulmonary hypertension.
- The exact mechanism behind this transient pulmonary hypertension remains unclear.
- Pulmonary intravascular macrophages (PIM) are known to interact with foreign particles.
Purpose:
- To investigate the role of pulmonary intravascular macrophages (PIM) in the pulmonary reactions following protamine reversal of heparin.
- To compare the sensitivity to protamine reversal between species with high PIM populations (goats) and low PIM populations (rabbits).
- To assess the relevance in human patients undergoing cardiac surgery.
Summary:
- Goats, possessing a large population of PIM, exhibited significant increases in mean pulmonary arterial and peak airway pressures after protamine administration.
- Rabbits and human patients, with fewer PIM, did not show significant changes in these hemodynamic parameters.
- These findings suggest that PIM play a crucial role in the pulmonary reactions observed after protamine reversal.
Impact:
- This research identifies pulmonary intravascular macrophages (PIM) as a key factor in protamine-induced pulmonary hypertension.
- Understanding this mechanism could lead to improved patient management and reduced side effects in cardiovascular surgery.
- The study highlights species-specific differences in PIM populations and their implications for drug-induced reactions.