Fluid Resuscitation After Cardiac Surgery: The Quest for the Ideal Fluid

Abstract

We congratulate the Journal as well as the authors of the HAS FLAIR1Wigmore G. Anstey J et al.20% Human Albumin Solution FLuid Bolus AdministratIon TheRapy in Patients after Cardiac Surgery (the HAS FLAIR study).J Cardiothorac Vasc Anesth. 2019; 33: 2920-2927Abstract Full Text Full Text PDF PubMed Scopus (17) Google Scholar trial for publishing promising results suggesting improved hemodynamics with the addition of only 2 boluses of 20% albumin before an established crystalloid regimen for post-cardiac surgery resuscitation. The authors quite rightly point out the inherent limitations of an open-label pilot study of this nature, but these cannot be overstated. By limiting the description of exclusion criteria, as well as a CONSORT diagram explaining decisions made about screening and inclusion, it is hard to reassure the reader of selection bias, especially following the introduction of a novel approach in this sequential nature. Could 50 eligible patients ever make it consecutively into an intervention group? The absence of randomization and blinding also disposes this work to confirmatory bias, particularly when triggers for the primary outcome (administration of fluid) include “perceived hypovolemia.” Conscious or unconscious bias toward the intervention could, as one example, persuade a clinician to be restrictive on the intensive care unit (ICU) after albumin administration, while waiting for the perceived benefit to take place. Likewise, the open-label nature of this study may have influenced the initiation of renal replacement therapy or inotropes, as well eventual discharge from the ICU and hospital. This is best demonstrated in figure 2 of the study1Wigmore G. Anstey J et al.20% Human Albumin Solution FLuid Bolus AdministratIon TheRapy in Patients after Cardiac Surgery (the HAS FLAIR study).J Cardiothorac Vasc Anesth. 2019; 33: 2920-2927Abstract Full Text Full Text PDF PubMed Scopus (17) Google Scholar, where we can see that fluid was administered to the control arm at a starting mean arterial pressure of over 90 mmHg, some 20 mmHg higher than the albumin arm of the study. It is indeed promising to read of lower net positive fluid balance in the intervention group as per the ALBIOS2Caironi P. Tognoni D Masson S et al.Albumin replacement in patients with severe sepsis or septic shock.N Engl J Med. 2014; 370: 1412-1421Crossref PubMed Scopus (602) Google Scholar trial, but it is not clear to us if other confounders exist. Of note, the control group received more than twice the amount of packed red cells as the intervention arm, but differences in other blood products go unreported. Likewise the use of inotropes, including doses for the protocolized dobutamine, could also affect physiologic parameters. Furthermore, the overall fluid balance may be manipulated through the use of diuretic therapy, and we wonder if this was similar between the groups. We look forward to seeing if a blinded (at least partially) and randomized controlled trial can replicate these impressive results. The authors have no conflicts of interest to disclose. 20% Human Albumin Solution Fluid Bolus Administration Therapy in Patients After Cardiac Surgery (the HAS FLAIR Study)Journal of Cardiothoracic and Vascular AnesthesiaVol. 33Issue 11PreviewTo compare the effects of fluid bolus therapy using 20% albumin versus crystalloid on fluid balance, hemodynamic parameters, and intensive care unit (ICU) treatment effects in post–cardiac surgery patients. Full-Text PDF HAS FLAIR Investigators Reply to Fluid Resuscitation After Cardiac Surgery: The Quest for the Ideal FluidJournal of Cardiothoracic and Vascular AnesthesiaVol. 33Issue 11PreviewFirst, we would like to thank Curtis and Anwar for their interest in our article “20% Human Albumin Solution Fluid Bolus Administration Therapy in Patients After Cardiac Surgery (the HAS FLAIR Study).”1 In their letter to the editor, Curtis and Anwar inquire about potential selection bias and confounders. Full-Text PDF