Systematic review and meta-analysis

Central venous pressure cannotpredict fluid-responsiveness10.1136/eb-2013-101496

Maurizio Cecconi, Hollman D Aya

Department of Intensive Care Medicine, St George’s Hospital, London, UK

Correspondence to: Dr Maurizio Cecconi, Critical Care, St George’sHospital, Blackshaw Road, London SW170QT, UK; m.cecconi@nhs.net

Commentary on: Marik PE, Cavallazzi R. Does the central venouspressure predict fluid responsiveness? An updated meta-analysisand a plea for some common sense. Crit Care Med2013;41:1774–81.

ContextCentral venous pressure (CVP) has been extensively studied in relation topreload and preload responsiveness. In 2008 Marik et al1 showed theinability of CVP and Δ-CVP to evaluate blood volume status and predictfluid-responsiveness in a systematic review and meta-analysis of 24studies. In spite of that level of evidence, surviving sepsis campaignguidelines still recommend targeting CVP in order to guide fluid therapyin severe sepsis and septic shock. Interestingly, in Rivers’ study,2 one ofthe studies referenced to use CVP, the same CVP target values were usedin the control as well as the goal-directed therapy group. We wouldargue that the choice of a CVP target between 8 and 12 mm Hg is, atleast, debatable.

MethodsMarik et al3 repeated the meta-analysis including a total of 43 studies.Both authors searched at MEDLINE, EMBASE and Cochrane Database ofSystematic Reviews and they also reviewed references of selected articles.The search strategy included as keywords ‘CVP’ (explode) and ‘fluidtherapy’ or ‘fluid-responsiveness’. The search was restricted to studiesperformed in human adults and studies that reported the correlation coef-ficient or the area under the receiver operating characteristic curve (AUC)between the CVP and the change in cardiac performance after a fluidchallenge, a passive leg raising manoeuvre or positive end-expiratorypressure challenge. No review protocol was reported and no electronicsearch strategy example was published. Meta-analysis of correlation coef-ficient and AUC were performed using random effects model, and assess-ment of heterogeneity and inconsistency was performed using the I2

statistic. No assessment of publication bias was reported. Subgroup ana-lysis is reported according to the location where the study was performed(intensive care unit vs operating theatre).

FindingsOnce again, the authors demonstrated that CVP is not able to predictfluid-responsiveness among patients under a broad range of interventionsand clinical settings. The summary AUC was 0.56 (95% CI 0.54 to 0.58)

without heterogeneity across studies (I2=0%). The authors concluded thatthe use of CVP to guide fluid therapy should be abandoned.

CommentaryThis meta-analysis confirms the findings of many studies published inthe literature. Given the number of studies included and the lack of het-erogeneity reported, its reliability and generalisability seems quite solid.They demonstrated that CVP is clearly not able to predictfluid-responsiveness.

Does this mean that we should abandon the measurement of CVP atthe bedside? Whereas we believe that the best way to assess and predictfluid-responsiveness can be achieved with the use of a flow monitor,4 wedo believe that rapid changes in CVP during fluid loading can provideinformation about cardiac function. Weil and Henning5 already proposedthis approach in a ‘fluid challenge’ technique in 1979. The ‘change inCVP’ must not be confused with ‘CVP trends’. It is a rather dynamicassessment of the cardiovascular system during fluid challenge.Interestingly, to our knowledge there are not many papers that studiedCVP in this way. Venn et al6 studied a goal-directed therapy approach inorthopaedic surgery. They studied three groups: a control group, onegroup where fluids were guided by dynamic assessment of CVP and onegroup where fluid challenges were guided by a flow monitor. The CVP aswell as the flow monitor groups had better outcomes than the controlgroup.

Furthermore, two studies from Magder7 8 suggested that respiratoryvariations of CVP could predict fluid-responsiveness in patients on spon-taneous ventilations. We suspect that dynamic changes of CVP have notbeen fully investigated.

In conclusion, the elegant work of Marik shows that we keep focusingon the wrong use of CVP. We do think that we should not abandon the CVPtool altogether but rather the wrong way this tool has been used so far.

Competing interests MC was involved in the consultancy/advisoryboard/research support, Edwards Lifesciences, LiDCO, Applied Physiology.HDA was involved in the research support, Applied Physiology.

References1. Marik PE, Baram M, Vahid B. Does central venous pressure predict fluid

responsiveness? A systematic review of the literature and the tale of seven mares.Chest 2008;134:172–8.

2. Rivers E, Nguyen B, Havstad S, et al. Early goal-directed therapy in the treatmentof severe sepsis and septic shock. N Engl J Med 2001;345:1368–77.

3. Marik PE, Cavallazzi R. Does the central venous pressure predict fluidresponsiveness? An updated meta-analysis and a plea for some common sense.Crit Care Med 2013;41:1774–81.

4. Cecconi M, Parsons AK, Rhodes A. What is a fluid challenge? Curr Opin Crit Care2011;17:290–5.

5. Weil MH, Henning RJ. New concepts in the diagnosis and fluid treatment ofcirculatory shock. Thirteenth Annual Becton, Dickinson and Company OscarSchwidetsky Memorial Lecture. Anesth Analg 1979;58:124–32.

6. Venn R, Steele A, Richardson P, et al. Randomized controlled trial to investigateinfluence of the fluid challenge on duration of hospital stay and perioperativemorbidity in patients with hip fractures. Br J Anaesth 2002;88:65–71.

7. Magder S, Georgiadis G, Cheong T. Respiratory variations in right atrial pressurepredict the response to fluid challenge. J Crit Care 1992;7:76–85.

8. Magder S, Lagonidis D. Effectiveness of albumin versus normal saline as a test ofvolume responsiveness in post-cardiac surgery patients. J Crit Care 1999;14:164–71.

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