Evaluate the effects of fluid loading on hemodynamics and cerebral perfusion under different levels of intra-abdominal pressure

Abstract

Objective To study the effects of fluid loading during fluid resuscitation on hemodynamics and cerebral perfusion(CPP)under different levels of intra-abdominal pressure(IAP). Methods Forty swine were employed in the study. Hypovolemia was made by blood withdrawal of 30% of estimated blood volume from each animal through the carotid artery line. All swine were randomized(random number) into four groups, namely IAPL0, IAPL15, IAPL25 and IAPL35. Then N2 gas was used to inflate in the abdomen slowly for elevating the IAP to 0, 15, 25 and 35 mmHg. Fluid loading were performed with 500 mL hydroxyethyl starch within 30 minutes. Hemodynamic variables were evaluated by PiCCO. Heart rate (HR), mean arterial pressure(MAP), central venous pressure(CVP), cardiac output(CO), global end-diastolic volume index(GEDVI) and stroke volume index(SVI)were measured 30 minutes before fluid loading and 30 minutes after fluid loading. After placement of intracranial pressure optical fiber probe in the ventricle connected to intracranial pressure monitor for continuous monitoring of ICP changes, cerebral perfusion pressure (CPP) could be calculated. Results (1)HR decrease, MAP increased, SVI, CI and GEDVI significantly increased after fluid loading in all four groups (IAPL0, IAPL15, IAPL25 and IAPL35)(P 0.05). SVRI decreased significantly in group IAPL15, IAPL25 and IAPL35 respectively(P 0.05). Conclusion When combined with intra-abdominal hypertension, fluid loading could improve the circulation of swine due to increase in CO and improve CPP. Key words: Intra-abdominal hypertension; Cardiac output; Fluid loading; Stroke volume variation; Intracranial pressure; Cerebral perfusion pressure