ABSTRACT
Objective To explore the body temperature thresholds of shivering in febrile rats during therapeutic hypothermia, and establish rat models of shivering in different degrees. Methods A randomized controlled trial was adopted. Rats weighted 200 ± 20 g and basal body temperature of 36. 8-38. 3℃ were induced with fever using 20% dry yeast solution through dorsal subcutaneous injection. 40 rats were randomly divided into 4 groups:10 mL ice pack group, 20 mL ice pack group, 40 mL ice pack group and control group, 10 rats in each group. Physical cooling was implemented for 30 minutes in the neck and armpits. No cooling measures was given to the control group. The shivering of rats were observed, and the threshold of anal temperature was monitored. Results In the rats with hyperthermia, shivering was not observed in any part of the rats in the control group and in the therapeutic hypothermia group of 10 mL ice pack. The rats in the therapeutic hypothermia group of 20 mL ice pack developed mild shivering, which manifested as piloerection, head and neck trembling, with or without upper limbs trembling. The threshold of the average rectal temperature of mild shivering was 37. 25℃, The incidence of mild shivering was 100%. The rats in the therapeutic hypothermia group of 40 mL ice pack developed severe shivering, which manifested as piloercetion, head, neck, limbs and trunk were trembling, and tail muscle tension increased. The threshold of the average rectal temperature of severe shivering was 37. 07℃, severe shivering occurred in 90% of the rats. Conclusions No shivering, mild shivering, and severe shivering models can be established by intervention with ice pack in rats with high fever during therapeutic hypothermia.
ABSTRACT
Objective To explore the body temperature thresholds of shivering in febrile rats during therapeutic hypothermia, and establish rat models of shivering in different degrees. Methods A randomized controlled trial was adopted. Rats weighted 200 ± 20 g and basal body temperature of 36. 8-38. 3℃ were induced with fever using 20% dry yeast solution through dorsal subcutaneous injection. 40 rats were randomly divided into 4 groups:10 mL ice pack group, 20 mL ice pack group, 40 mL ice pack group and control group, 10 rats in each group. Physical cooling was implemented for 30 minutes in the neck and armpits. No cooling measures was given to the control group. The shivering of rats were observed, and the threshold of anal temperature was monitored. Results In the rats with hyperthermia, shivering was not observed in any part of the rats in the control group and in the therapeutic hypothermia group of 10 mL ice pack. The rats in the therapeutic hypothermia group of 20 mL ice pack developed mild shivering, which manifested as piloerection, head and neck trembling, with or without upper limbs trembling. The threshold of the average rectal temperature of mild shivering was 37. 25℃, The incidence of mild shivering was 100%. The rats in the therapeutic hypothermia group of 40 mL ice pack developed severe shivering, which manifested as piloercetion, head, neck, limbs and trunk were trembling, and tail muscle tension increased. The threshold of the average rectal temperature of severe shivering was 37. 07℃, severe shivering occurred in 90% of the rats. Conclusions No shivering, mild shivering, and severe shivering models can be established by intervention with ice pack in rats with high fever during therapeutic hypothermia.