Effects of hetastarch and mannitol on prolonging survival in stable hypothermia in rats

Abstract

In rats, prolonged stable hypothermia ( approximately 24 h at body temperature of 19 degrees C) is characterized by a time-dependent increase in hematocrit, plasma osmolality, and red blood cell fragility and a decrease in plasma volume. These changes impede tissue microcirculation and could limit survival. As a countermeasure, we used plasma volume expanders of both long (hetastarch)- and short-lasting (mannitol) characteristics to improve microcirculation and hopefully hypothermia survival. Infusion of 6% hetastarch at hour 3 in hypothermia significantly (P < 0.05) enhanced survival over saline control (33.5 vs. 23.8 h); a significant delay in the increases of hematocrit and cell fragility was also observed compared with those in saline controls. Treating the animal with 6% hetastarch at hour 20 during hypothermia caused a similar but less-effective improvement in survival. In contrast, treating the rats with 6% mannitol at hour 3 or 20 during hypothermia failed to enhance survival over saline control, although transient improvement in plasma volume was observed. Our results indicate that by using a long-lasting volume expander, which tends to better maintain plasma volume and rheological parameters governing microcirculation than does saline or a short-lasting volume expander, hypothermia survival can be significantly improved.

Oxidative Stress and Antioxidant Activity in Hypothermia and Rewarming: Can RONS Modulate the Beneficial Effects of Therapeutic Hypothermia?

“…In fact, the combination of hypothermia and acidosis is seen as a critical point in the injured by trauma [ 42 ]. The failure of respiratory and/or renal functions, acid/base regulation, and ion regulatory mechanisms has been suggested as critical during severe hypothermia [ 43 ].…”

Hypometabolic induced state: a potential tool in biomedicine and space exploration

“…On the other hand, super cooling can be dangerous because it is a metastable condition where ice nucleation starts with ease. Interestingly, it has been found (Lee et al 2000) that in rats infusion of the long-lasting volume expander hetastach was able to improve survival during hypothermia (22°C).…”