Effects of hypertonic versus isotonic infusion therapy on regional cerebral blood flow after experimental cardiac arrest cardiopulmonary resuscitation in pigs.

OBJECTIVE: To evaluate the effects of hypertonic, isooncotic, and isotonic infusion therapy on cerebral blood flow (CBF) during and after cardiopulmonary resuscitation (CPR) from experimental cardiac arrest (CA).
METHODS: In 32 domestic swine (13-23 kg) open chest CPR was initiated after 8 min of ventricular fibrillation. With the onset of CPR animals randomly received 2 ml/kg per 10 min of either hypertonic saline (HS: 7.2% NaCl), hypertonic-isooncotic HES-saline (HHS: 7.2% NaCl in 6% HES 200,000/0.5), isooncotic HES (6% HES 200,000/0.5), or isotonic (normal) saline (NS: 0.9% NaCl). Haemodynamic variables were monitored continuously, and coloured microspheres were used to measure CBF quantitatively before CA, during CPR, and 20, 90 and 240 min after restoration of spontaneous circulation (ROSC).
RESULTS: In HES/NaCl treated animals, CBF significantly decreased during CPR compared to the prearrest level (P < 0.01, respectively; MANOVA). In contrast, CBF was sustained during CPR in HS/HHS treated animals and significantly higher compared to animals receiving NS (P < 0.05, respectively). During recirculation severe postischaemic hypoperfusion as indicated by a decrease of CBF below the prearrest level, was present only in animals receiving HES and NS.
CONCLUSIONS: Hypertonic solutions (HS/HHS) applied during internal cardiac massage enhanced CBF during CPR and after ROSC.