1. Rates of adverse outcomes amongst cardiac surgery patients randomized to receive either Ringer acetate or 4% albumin solution for perioperative volume support were not significantly different.

2. The findings reported in this study do not support the routine use of 4% albumin for volume resuscitation in the perioperative setting.

Level of Evidence Rating: 1 (Excellent)

Study Rundown: The maintenance of hemodynamic stability during cardiac surgery remains an ongoing challenge. Theoretically, colloid solutions such as albumin may resuscitate the intravascular space to maintain effective circulating volume better than crystalloid solutions. Drawbacks of this approach include the threat to kidney function and cost associated with colloid solutions. The present study sought to compare the safety and efficacy of 4% albumin solution versus Ringer acetate solution for perioperative fluid resuscitation given to cardiac surgery patients.

In total,1407 patients were randomized, with 705 in the control group receiving Ringer acetate and 702 in the experimental group receiving 4% albumin solution. The primary endpoint of this trial was the number of patients in each group who experienced at least one major adverse event within 90 days of surgery. A major adverse event was experienced by 37.1% of the experimental group and 33.8% of the control group; this difference was not statistically significant. However, albumin patients did experience significantly higher rates of re-sternotomy, infection and bleeding events than the Ringer group, and significantly fewer myocardial injuries postoperatively. Additionally, patients in the control group required significantly more fluid by volume than those in the experimental group.

This randomized controlled trial by Pesonen et al found that the safety and efficacy of albumin used for fluid resuscitation in the perioperative period in cardiac surgery patients is not significantly different from that of standard crystalloid. A major drawback of this trial is the primarily pragmatic design, as evidenced by strict eligibility criteria such that these results may not reflect the average cardiac surgery patient population. An advantage of this study is the randomized design which does well to control for confounding variables and the large sample size. The findings reported in this study do not support the routine use of 4% albumin for volume resuscitation in the perioperative setting.

Click here to read this study in JAMA

Click to read an accompanying editorial in JAMA

Relevant Reading: Hypertonic saline for fluid resuscitation in ICU patients post-cardiac surgery (HERACLES): a double-blinded randomized controlled clinical trial

In Depth [randomized controlled trial]: A single center, double-blinded randomized controlled trial was conducted in Helsinki, Finland. Patients aged 18 to 90 years old who were undergoing elective, open heart surgery were included. Exclusion criteria included patients who had emergency surgery, infection, heart failure or low output syndromes, end stage kidney disease or hemophilia. Patients who had used antiplatelet or anticoagulant therapy within 2 days of surgery, or those who did not consent to receiving blood products were also excluded. Eligible patients were randomized in a 1:1, block-based fashion by the hospital pharmacy. Patients received the study fluids during cardiopulmonary bypass and for up to 24 hours postoperatively in the intensive care unit to a maximum of 3200 mL (at which point all patients were given Ringer acetate).

Patients were recruited between March 21, 2017 and January 14, 2020. Most patients in each group underwent CABG surgery only (322 in the albumin group and 304 in the control group). The median fluid requirement in the albumin group was 2150mL (interquartile range 1598-2700mL) and was 3298mL in the Ringer acetate group (2669-3500; p< 0.001). The relative risk of experiencing a major adverse event in the albumin group compared with the control group was 1.01 (95% confidence interval 0.95 to 1.27). The relative risks for the following adverse events favoring the control groups were as follows: re-sternotomy 1.85 (1.28 to 2.68), infection 1.45 (1.07 to 1.97) and bleeding 1.73 (1.12 to 2.68). Albumin was protective against myocardial injury in this trial, with a relative risk of 0.44 (0.28 to 0.68) compared to the control group. The rate of serious adverse events was not significantly different between the two groups.

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