Predicting fluid response in ICU

Information about Predicting fluid response in ICU

Published on July 17, 2010

Author: fergusona

Source: authorstream.com

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Predicting fluid responsein the critically ill : Predicting fluid responsein the critically ill Dr. Andrew Ferguson Consultant in Anaesthesia & Intensive Care Medicine Craigavon Area Hospital Approach to shock : Approach to shock Fluid challenge central to therapy +/- CVP (and/or PA) monitoring Repeat if CVP/PAWP still low Stop if CVP/PAWP goes high Surrogate markers for CO Lactate SvO2 So what’s the problem? : So what’s the problem? ? validity of CVP as end-point ? validity of PAWP as end-point Preload-SV relationship unknown Only 50% of patients fluid-responsive Excess fluid problems Interstitial fluid excess Worsened gas exchange Limitation of oxygen diffusion Variability of fluid response rates : Variability of fluid response rates Michard (Chest 2002; 121: 2000-2008) Preload does not guarantee response : Preload does not guarantee response To be a fluid responder, bothventricles must be on ascendingportion of Frank-Starling curve : To be a fluid responder, bothventricles must be on ascendingportion of Frank-Starling curve Response depends on contractility and diastolic function as well as load Common measures used to indicate likelihood of response : Common measures used to indicate likelihood of response CVP PAWP RVEDV (thermodilution) LVEDA (echo) Slide 9: R2 = 0.2 In spontaneous resp. a fall > 1 mmHg in RAP has positive predictive value of 77-84% and negative predictive value of 81-93% for response Slide 10: R2 = 0.33 Slide 12: ROC curve minimal correlation They don’t work---what next?? : They don’t work---what next?? BP change relates to SV change : BP change relates to SV change Cardio-pulmonary interactions : Cardio-pulmonary interactions Changes in SV, PP, SBP with positive pressure ventilation Slide 18: Increased pleural pressure RV preload falls LV afterload falls Increased transpulmonary pressure RV afterload increases LV preload increased by alveolar vessel squeeze Decreased RVSV Increased LVSV Slide 19: Inspiratory decrease in RVSV Expiratory decrease in LVSV Expiratory decrease in LV preload Pulmonary transit time Stroke volume variation and LVEDP : Stroke volume variation and LVEDP Potential tools : Potential tools Stroke volume variation Systolic pressure variation Pulse pressure variation Peak aortic blood flow velocity variation Systolic Pressure Variation : Systolic Pressure Variation Ddown is the important one for fluid response Systolic pressure variation : Systolic pressure variation DSP as indicator of fluid response : DSP as indicator of fluid response Pulse pressure variation : Pulse pressure variation DPP as indicator of fluid response : DPP as indicator of fluid response Measures of response to volume : Measures of response to volume Predictive values : Predictive values Problems with DPP and DSV : Problems with DPP and DSV Equipment not universal Need sinus rhythm False positive in severe abdominal distension Normal values : Normal values DPP 13% SPV Ddown 5% DVpeak (aortic blood flow velocity) 12% DSV 10% Conclusions : Conclusions Conventional measures often not valid New and accurate measures available Consider passive leg raising! Know cardio-pulmonary interactions

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