Experimental hypothermia and rewarming: changes in mechanical function and metabolism of rat hearts
| Autor: | M. Skandfer, Refsum H, Kirsti Ytrehus, Torkjel Tveita |
|---|---|
| Rok vydání: | 1996 |
| Předmět: |
Male
medicine.medical_specialty Cardiac output Circulatory collapse Physiology Blood Pressure Biology Ventricular Function Left Body Water Heart Rate Hypothermia Induced Physiology (medical) Internal medicine Heart rate medicine Animals Cardiac Output Rats Wistar Rewarming Energy charge Myocardium Heart Stroke volume Hypothermia medicine.disease Myocardial Contraction Rats Surgery Blood pressure Circulatory system Cardiology Blood Gas Analysis medicine.symptom Energy Metabolism |
| Zdroj: | Journal of Applied Physiology. 80:291-297 |
| ISSN: | 1522-1601 8750-7587 |
| DOI: | 10.1152/jappl.1996.80.1.291 |
| Popis: | Rewarming from accidental hypothermia is associated with fatal circulatory derangements. To investigate potential pathophysiological mechanisms involved, we examined heart function and metabolism in a rat model rewarmed after 4 h at 15-13 degrees C. Hypothermia resulted in a significant reduction of left ventricular (LV) systolic pressure, cardiac output, and heart rate, whereas stroke volume increased. The maximum rate of LV pressure rise decreased to 191 +/- 28 mmHg/s from a control value of 9,060 +/- 500 mmHg/s. Myocardial tissue content of ATP, ADP, and glycogen was significantly reduced, whereas lactate content remained unchanged. After rewarming, heart rate returned to control value, whereas LV systolic pressure, cardiac output, and stroke volume all remained significantly depressed. The posthypothermic maximum rate of LV pressure rise was 5,966 +/- 1.643 mmHg/s. The posthypothermic myocardial lactate content was significantly increased (to 13.3 +/- 3.2 nmol/mg from control value of 5.7 +/- 1.9 nmol/mg), and ATP and glycogen remained significantly lowered. Creatine phosphate or energy charge did not change significantly during the experiment. The finding of deteriorated myocardial mechanical function and a shift in energy metabolism shows that the heart could be an important target during hypothermia and rewarming in vivo, thus contributing to the development of a posthypothermic circulatory collapse. |
| Databáze: | OpenAIRE |
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