Assessment of intravascular volume by transthoracic echocardiography during therapeutic hypothermia and rewarming in cardiac arrest survivors.
OBJECTIVE
To study haemodynamic effects and changes in intravascular volume during hypothermia treatment, induced by ice-cold fluids and maintained by ice-packs followed by rewarming in patients after resuscitation from cardiac arrest.


METHODS
In 24 patients following successful restoration of spontaneous circulation (ROSC), hypothermia was induced with infusion of 4 degrees C normal saline and maintained with ice-packs for 26 h after ROSC. This was followed by passive rewarming. Transthoracic echocardiography was performed at 12, 24 and 48 h after ROSC to evaluate ejection fraction and intravascular volume status. Central venous pressure (CVP), central venous oxygen saturation (ScvO(2)) and serum lactate were measured. Fluid balance was calculated.


RESULTS
Twelve hours after ROSC, two separate raters independently estimated that 10 and 13 out of 23 patients had a decreased intravascular volume using transthoracic echocardiography. After 24 and 48 h this number had increased further to 14 and 13 out of 19 patients and 13 and 12 out of 21 patients. Calculated fluid balance was positive (4000 ml the day 1 and 2500 ml day 2). There was no difference in ejection fraction between the recording time points. Serum lactate and ScvO(2) were in the normal range when echocardiography exams were performed. CVP did not alter over time.


CONCLUSIONS
Our results support the hypothesis that inducing hypothermia following cardiac arrest, using cold intravenous fluid infusion does not cause serious haemodynamic side effects. Serial transthoracic echocardiographic estimation of intravascular volume suggests that many patients are hypovolaemic during therapeutic hypothermia and rewarming in spite of a positive fluid balance.
Nordmark
Johanna
J
Department of Surgical Sciences/Anaesthesiology, Intensive Care, Uppsala University, Sweden. johanna.nordmark@surgsci.uu.se
Johansson
Jakob
J
Sandberg
Dan
D
Granstam
Sven-Olof
SO
Huzevka
Tibor
T
Covaciu
Lucian
L
Mörtberg
Erik
E
Rubertsson
Sten
S
D000368:Aged; D001810:Blood Volume / Q000502:physiology*; D001811:Blood Volume Determination / Q000379:methods*; D003325:Coronary Care Units; D004452:Echocardiography / Q000379:methods*; D005260:Female; D005440:Fluid Therapy / Q000379:methods; D005500:Follow-Up Studies; D006323:Heart Arrest / Q000000981:diagnostic imaging* / Q000503:physiopathology / Q000628:therapy; D006801:Humans; D007036:Hypothermia, Induced / Q000379:methods*; D007262:Infusions, Intravenous; D007552:Isotonic Solutions / Q000008:administration & dosage; D008297:Male; D008875:Middle Aged; D012189:Retrospective Studies; D017694:Rewarming / Q000379:methods*; D016896:Treatment Outcome
D007552:Isotonic Solutions