The effect of prior hypothermia on the physiological response to norepinephrine

• Published in: Resuscitation 2000-08, Vol.45 (3), p.201-207
• Main Authors: Weiss, Steven J, Muniz, Antonio, Ernst, Amy A, Lippton, Howard L, Nick, Todd G
• Format: Article
• Language: English
• Subjects: Anesthesia. Intensive care medicine. Transfusions. Cell therapy and gene therapy; Animals; Biological and medical sciences; Blood Pressure - drug effects; Cardiac output; Cardiac Output - drug effects; Catecholamines; Cats; Dose-Response Relationship, Drug; Emergency and intensive care: injuries, diseases due to physical agents. Diving. Drowning. Disaster medicine; Hemodynamics - drug effects; Hypothermia; Hypothermia - physiopathology; Intensive care medicine; Medical sciences; Norepinephrine; Norepinephrine - pharmacology; Vascular Resistance - drug effects
• ISSN: 0300-9572; 1873-1570
• DOI: 10.1016/S0300-9572(00)00185-4

Objective: this study determines the effect of prior hypothermia on the cardiovascular responses to norepinephrine (NE) after rewarming. Methods: the experiment was a 2×2 controlled design with four groups of feline animals. The two variables were the presence or absence of previous cooling, and the use or non-use of NE after rewarming. During the ‘cooling’ phase, animals were either cooled using an external arterial–venous femoral shunt to 30°C or maintained at 37°C. After ‘rewarming’ animals were stratified to receive either NE at rates to deliver 0.2, 1.0 or 5 μg/kg per h or normal saline infusions. Animals were instrumented to measure mean arterial pressure (MAP) and cardiac output (CO) and systemic vascular resistance (SVR) was calculated. Results: there were no differences between groups at baseline and low dose NE (0.2 μg/kg per min). At 1.0 μg/kg per min, NE caused a significant increase in CO ( P