Central Venous Pressure And Inferior Vena Cava Distensibility Index On Assessment Of Volume Status In Septic Patients With Mechanical Ventilation

Objective:To explore the value of central venous pressure(CVP) and inferior vena cava distensibility index(dIVC) on assessment of volume status in septic patients with mechanical ventilation.Methods:16 septic patients with positive pressure ventilation and CVP above 20 cm H₂O who underwent CBP treatment were selected as the study population.High CVP was reduced to target value 12 cm H₂O through ultrafiltxation regulation in 8 hours after CBP. CVP,Heart rate(HR),mean arterial pressure(MAP),cardiac index(CI) and dIVC were monitored and detected at intervals both before and after the treatment of CBP.Results:The CVP,IVCD_-E,dIVC and CI were(26.0±4.9)cmH₂O,(2.2±0.2) cm, (16.1±1.6)%,(2.3±0.8) L/min/m² respectively before the application of CBP.When the ultrafiltration reached 6ml/Kg,the IVCD began to decreased and the dIVC began to increased(p＜0.05).When the ultrafiltration reached 10ml/Kg,the IVCD decreased and the dIVC increased significantly with the CI improved(p＜0.05).When the ultrafiltration came to 18ml/Kg,the CVP decreased to(21.6±5.5) cmH₂O.At the same time the MAP and HR improved(p＜0.05).When the ultrafiltration was 25ml/Kg,the CI gained its maximum.The value of CVP,IVCD_-E and dIVC were(15.5±2.1) cmH₂O,(1.4±0.2) cm and(27.0±1.5)%respectively.There was strong correlation betweenâ–³CVP and ultrafiltration when the value of CVP was above 18cmH₂O(r=-0.597,p＜0.001 ).The ultrafiltration had significant correlation withâ–³IVCD_-E andâ–³dIVC(r=-0.865,r=0.887, p＜0.001).Significant correlation was also found between CVP and IVCD_-E when the value of CVP was(12-21) cmH₂O(r=0.750,p＜0.001).After that the CI and MAP decreased when the ultrafiltration was continued.Conclusions:CBP can improve the hyper- volume state of septic patients after fluid resuscitation.Within this period the dIVC was a more useful indicator than the CVP on the assessment of volume change.Although the CVP can not respond to volume change precisely,the CVP values range from 12cmH₂O to 21cmH₂O can indicate appropriate volume relatively.However,it should be pointed out that CVP below(15.5±2.1) cmH₂O may indicate hypo-volume.