Abstract P186: Large Volume, Ice-cold Intravenous Fluid for Therapeutic Hypothermia Does Not Compromise the Respiratory Situation in Patients after Cardiac Arrest
Background: The AHA guidelines for cardiopulmonary resuscitation (2005) recommend a mild hypothermia (32–34 °C) for 24 hours after cardiac arrest, as it significantly improves survival and neurological outcome. To induce therapeutic hypothermia a variety of external and intravascular cooling devices are offered that are often expensive and unavailable in many hospitals. A cheap and effective alternative is the infusion of large volume, ice-cold intravenous fluid. With respect to the frequently reduced LV-function in resuscitated patients, there are often concerns regarding the rapid infusion of large volumes. Therefore, we examined the influence of high volume infusion on the respiratory situation in resuscitated patients.
Methods: We retrospectively analyzed the data from 52 patients (age 61.3±2.3 years) during the post-resuscitative hypothermia period. Hypothermia was induced in all patients that remained unconscious after return of spontaneous circulation (ROSC). Under deep sedation and neuromuscular relaxation and in addition to external cooling, large volume of ice-cold saline (2–4 °C) was infused.
Results: The target temperature of 32–34 °C was achieved after 4.1±0.5 h (cooling velocity 0.48 °C/h). During this period 3427±210 mL ice-cold fluid was infused. Despite significantly reduced LV-function (EF 35.8±2.2%) the respiratory situation of these patients did not deteriorate. Before starting the saline infusion, the mean arterial oxygen partial pressure (PaO2) was 231.4±20.6 mmHg at a FiO2 of 0.82±0.03 (PaO2/FiO2=290.0±24.1) and a PEEP of 7.14±0.31 mbar. Until reaching the target temperature (<34 °C) the FiO2 could be reduced to 0.63±0.03 with unchanged PEEP level (7.23±0.36 mbar). Under these conditions the patients mean PaO2 was 141.3±10 mmHg (PaO2/FiO2=247.5±18.4). Continuing the saline infusion to achieve a body temperature of 33 °C, the FiO2 could be further reduced with stable PaO2 (PaO2/FiO2=224.3±16.3).
Conclusions: The infusion of large volume, ice-cold saline is an effective, safe and inexpensive procedure for the induction of neuroprotective hypothermia. Despite significantly reduced LV-function in resuscitated patients, the infusion of large volumes does not deteriorate the respiratory situation.