In his PhD thesis, Brage Håheim has studied the effects of two common cardiovascular drugs during and after rewarming in an animal model of hypothermia.

MAIN RESULTS:

1. Levosimendan ameliorates systolic dysfunction induced by hypothermia in rats.
2. Sodium nitroprusside reduces the increased systemic vascular resistance induced by hypothermia.
3. Both drugs positively affects blood flow to the brain following severe hypothermia.

THESIS DEFENCE:

Thesis: The hemodynamic aspects of pharmacological manipulation of cardiac contractility and vascular resistance in rewarming from hypothermia
Candidate: Brage Håheim
Time: December 7, 2018 at 12:15
Place: UiT The Arctic University of Norway, MH Building: Store auditorium
Link to university website (in Norwegian)

SUMMARY:

(1) One of Håheim’s articles shows that levosimendan helps restore stroke volume, cardiac output and preload recruitable stroke work to within pre-hypothermic values following severe hypothermia. The rats in the study were cooled down to 15 °C for four hours before rewarming, and levosimendan proved more effective than placebo. The researchers conclude that inotropy during rewarming from severe hypothermia is better achieved through calcium sensitizing and inhibition of PDE3 than through beta-receptor stimulation.

(2) Arterial dilatation by use of sodium nitroprusside during rewarming from severe hypothermia reduces afterload and improves stroke volume and cardiac output more than placebo. However, sodium nitroprusside does not fully alleviate cardiac output, and preload recruitable stroke work was similarly decreased in both rat groups following rewarming.

(3) Levosimendan and sodium nitroprusside have beneficial effects on blood flow to the brain following rewarming from severe hypothermia in rats.

REFERENCES:

(1) Dietrichs, E. S., Håheim, B., Kondratiev, T., Sieck, G. C., & Tveita, T. (2014). Cardiovascular effects of levosimendan during rewarming from hypothermia in rat. Cryobiology, 69(3), 402-410.

(2) Håheim, B., Kondratiev, T., Dietrichs, E. S., & Tveita, T. (2017). The beneficial hemodynamic effects of afterload reduction by sodium nitroprusside during rewarming from experimental hypothermia. Cryobiology, 77, 75-81.