The act of re-warming may precipitate cardiovascular collapse ('re-warming shock') and rhythm change.
The reasons are not completely understood but include electrolyte shifts, temperature fluctuation, intravascular depletion and drug therapy [4]. This will, of course, not be an issue if bypass is used to re-warm. Patients should be adequately volume loaded to maximise cardiac output during the re-warming process. In the absence of cardiac output monitoring aim for a central venous pressure (CVP) of 8-12 cm H2O.