| PartⅠ[Abstract] Objective:The study was designed to evaluate the effects of different grades of intra-abdominal pressure(IAP) in the model of hypovolemia on hemodynamics and cerebral perfusion(CPP).Method:Forty pigs were involved in the study. Hypovolemia was made by blood withdrawal of30%of estimated blood volume from each animal through the Carotid artery line. All the pigs were randomized into four groups named IAPL0, IAPL15, IAPL25and IAPL35. Then N2was inflated slowly,elevating the LAP to0,15,25and35mmHg. Hemodynamic parameters were evaluated by using the thermo dilution technique of pulse induced continuous cardiac output (PiCCO). After30minutes of stabilization, heart rate (HR),mean arterial pressure(MAP),central venous pressure(CVP),cardiac output(CO), global end-diastolic volume index(GEDVI), SVV and stroke volume index(SVT) were measured. Through the ventricle with intracranial pressure optical fiber probe, connected intracranial pressure monitor continuous monitoring of ICP changes, calculation of cerebral perfusion pressure (CPP). Results:(1) Compared with group IAPL0, HR increased significantly, while SVI, GEDVI decreased and SVRI and CVP increased in group IAPL15IAPL25and IAPL35respectively (P<0.05), and there were statistically significant differences among groups(IAPL15,IAPL25and IAPL35)(P<0.05). when compared with IAPL0, MAP increased significantly in IAPL15(P<0.05), while no differences were found IAPL25and IAPL35(P>0.05).No statistical significance in CI in IAPL15(P>0.05) while CI were significant different in IAPL25and IAPL35(P<0.05). EVLWI did not change significantly among group IAPL0,IAPL15,IAPL25and IAPL35(P>0.05).(2) Compared with group IAPL0,ICP did not change significantly in IAPL15(P>0.05) while CPP increased significantly in IAPL25and IAPL3s(P<0.05),CPP did not change significantly among group IAPL15,IAPL25and IAPL35(P>0.05);when Compared with group IAPL15, CPP decreased significantly in group IAP125and IAPL35(P<0.05).Conclusions:Intra-abdominal hypertension decreased CO, increased ICP and decreased CPP. The higher the intra-abdominal pressure, the more significant effect.Part II[Abstract] Objective:The study was designed to evaluate the effects of fluid loading on hemodynamics and cerebral perfusion (CPP) in different grades of intra-abdominal pressure(IAP) combined with hypovolemia.Method:Forty pigs were involved in the study. Hypovolemia was made by blood withdrawal of30%of estimated blood volume from each animal through the Carotid artery line. All the pigs were randomized into four groups named IAPL0, IAPL15, IAPL25and IAPL35. Then N2was inflated slowly,elevating the IAP to0,15,25and35mmHg. Fluid loading were performed with500ml hydroxyethyl starch within30minutes. Hemodynamic parameters 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 before fluid loading and after fluid loading. Through the ventricle with intracranial pressure optical fiber probe, connected intracranial pressure monitor continuous monitoring of ICP changes, calculation of cerebral perfusion pressure (CPP). Results:(1)HR decrease, MAP increased, SVI, CI and GEDVI significantly increased after fluid loading in all the four groups (IAPL0,IAPL15,IAPL25and IAPL35)(P<0.05), there were not significant changes in EVLWI(P>0.05). CVP decreased significantly in group IAPLo(P<0.05) and CVP did not change significantly in group IAPL15,IAPL25and IAPL35(P>0.05). SVRI decreased significantly in group IAPL15,IAPL25and IAPL35respectively(P<0.05).(2) ICP increased significantly in group IAPL15, IAPL25and IAPL35(P<0.05), CPP increased significantly in group IAPL25and IAPL35(P<0.05) while slightly increased in group IAPL15(P>0.05).Conclusions:Fluid loading could improve the pigs’circulation due to a raise in CO, there should be careful of the risk of increased intracranial pressure.Part III[Abstract] Objective:The study was designed to evaluate the effectiveness of stroke volume variation(SVV)for predicting fluid responsiveness in different grades of intra-abdominal pressure(IAP).Method:Forty pigs were involved in the study. Hypovolemia was made by blood withdrawal of30%of estimated blood volume from each animal through the Carotid artery line. All the pigs were randomized into four groups named IAPL0, IAPL15, IAPL25and IAPL35.Then N2was inflated slowly,elevating the IAP to0,15,25and35mmHg. Fluid loading were performed with500ml hydroxyethyl starch within30minutes. Hemodynamic parameters were evaluated by PiCCO. Heart rate (HR),mean arterial pressure(MAP),central venous pressure(CVP),cardiac output(CO), global end-diastolic volume index(GEDVI), SVV and stroke volume index(SVI)were measured before fluid loading and after fluid loading. Through the ventricle with intracranial pressure optical fiber probe, connected intracranial pressure monitor continuous monitoring of ICP changes, calculation of cerebral perfusion pressure (CPP).Fluid responsiveness was defined as the change in SVI increased over15%after fluid loading (ΔSVI%≥15%).Results:(1) Compared with group IAPL0, SW significantly increased in IAPL15, IAPL25and IAPl35(P<0.05). when compared with group IAPl15, SW significantly decreased in group IAPL35(P<0.05), and no significant changes in Group IAPL25(P>0.05).(2) After fluid loading, SW decreased significantly (P<0.05) in IAPL0and did not change significantly in IAPL15, IAPL25and IAPL35(P>0.05).(3) In group IAP10,IAPL15,IAPL25and IAPL35,there were poor correlations between CVP and Δ SV%(r=0.205.-0.161.-0.24and0.217respectively, P>0.05).(4) In group IAPL0and IAPL15, SW was positive correlated with changes in SV (r=0.888,0.942, respectively, P<0.05), In group IAP125and IAPL35,there were poor correlations between SW and changes in SV(r=0.851,-0.114respectively, P>0.05).Conclusions: When IAP was slightly increased up to15mmHg, SW remains an accurate index to predicte of fluid responsiveness index, however it failed to predict fluid responsiveness effectively when IAP further raised up to25mmHg or more. |
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