Mild hypothermia reduces acute mortality and improves hemodynamic outcome in a cardiogenic shock pig model.
BACKGROUND
Cardiogenic shock is the main cause of death in patients hospitalized due to an acute myocardial infarction. Mild hypothermia reduces metabolism and could offer protective effects for this condition. The aim of our study was to investigate if mild therapeutic hypothermia would improve outcome and hemodynamic parameters in an ischemic cardiogenic shock pig model.


METHODS
Twenty-five pigs (40-50 kg) were anesthetized and a normothermic temperature of 38 degrees C was established utilising an endovascular cooling catheter in a closed-chest model. A Swan-Ganz catheter was placed in the pulmonary artery. Hemodynamic parameters were continuously monitored and blood gases were sampled every 30 min. Ischemia was induced by inflation of a PCI balloon in proximal LAD for 40 min. Sixteen pigs that have fulfilled predefined shock criteria were randomized to hypothermia (n=8), or normothermia (n=8). Hypothermia (33 degrees C) was induced after onset of reperfusion by using an endovascular temperature modulating catheter and was maintained until termination of the experiment.


RESULTS
The pigs in the hypothermia group were cooled to <34 degrees C in approximately 45 min. 5/8 pigs in the normothermia group died while all pigs in the hypothermia group survived (p<0.01). Stroke volume and blood pressure were significantly higher in the hypothermia group (p<0.05), whereas heart rate was significantly lower in the hypothermia group (p=0.01). Cardiac output did not differ among the groups (p=0.13). Blood gas analysis revealed higher mixed venous oxygen saturation, pH, and base excess in the hypothermia group indicating less development of metabolic acidosis (p<0.05).


CONCLUSIONS
In this pig model, mild therapeutic hypothermia reduces acute mortality in cardiogenic shock, improves hemodynamic parameters and reduces metabolic acidosis. These findings suggest a possible clinical benefit of therapeutic hypothermia for patients with acute cardiogenic shock.
Götberg
Matthias
M
Dept. of Coronary Heart Disease, Skane University Hospital, Lund University, S-22185, Lund, Sweden. matthias.gotberg@med.lu.se
van der Pals
Jesper
J
Olivecrona
Göran K
GK
Götberg
Michael
M
Koul
Sasha
S
Erlinge
David
D
D000138:Acidosis / Q000209:etiology / Q000503:physiopathology; D000818:Animals; D001145:Arrhythmias, Cardiac / Q000209:etiology; D001775:Blood Circulation; D001831:Body Temperature; D005260:Female; D005740:Gases / Q000097:blood; D006439:Hemodynamics; D007036:Hypothermia, Induced; D053208:Kaplan-Meier Estimate; D008297:Male; D009203:Myocardial Infarction / Q000150:complications*; D017202:Myocardial Ischemia / Q000150:complications / Q000628:therapy; D015425:Myocardial Reperfusion; D012720:Severity of Illness Index; D012770:Shock, Cardiogenic / Q000209:etiology* / Q000401:mortality* / Q000503:physiopathology / Q000628:therapy*; D013997:Time Factors
D005740:Gases