Background:
It is known, that albumin concentration in plasma significantly decreases during major surgery [1] and in critical illness mainly due to transcapillary leak and reduced synthesis[2]. Current data on the impact of anaesthesia on albumin kinetics is limited.
Goal:  
Goal of this study was to assess albumin kinetics during major abdominal surgery.
Materials and Methods:
A prospective, non-randomized observational study was held in clinic of anaesthesiology of Lithuanian University of Health Sciences Kaunas Clinics. Blood samples of 34 patients who underwent major abdominal surgeries were examined. Assays were taken before surgery, after induction of anaesthesia, at the end of the surgery and 24 hours after the surgery. Approval of Ethical review board was obtained before study initiation.  All participants gave informed signed consent to participate in the study.
Results and discussion:
34 patients were involved in the study. Average age was 67.86 (±15.86). Average duration of surgery was 278.11 (±85.06) minutes whereas average fluid consumption was 2691.18 (±1304.22) ml. Average fluid management - 7.33 ml/kg/h. There was a reduction in albumin concentration immediately following induction of anaesthesia (38.11 g/L to 33.67 g/L, p=0.000), it continued to decrease during the surgery (32.43 g/L, p=0.000,) and 24 hours after the surgery (30.24 g/L, p=0.000).  Overall percentage of albumin concentration reduction from the baseline was 11.66%, 14.91% and 20.65% respectively. 56.41% of overall decrease (7.87 g/L) was noted immediately after induction.
The findings demonstrate that albumin concentration at the end of the surgery decreased by 14.91% from the baseline value. A much larger reduction 40% was demonstrated in the recent study by Norberg and colleagues [1] in a similar patient population. The most interesting finding is that almost two thirds of overall albumin loss peri-operatively is noted immediately after the induction and it raises the question, what are the main triggers and how we can avoid them. 
Conclusion:
Our study shows that there is significant and gradual reduction of albumin concentration in major abdominal surgery. Most significant decrease was noted immediately after the induction of anaesthesia. Further studies needed.
References:
1.        Norberg A et al. Leakage of albumin in major abdominal surgery. Critical Care 2016 20:113. 
2.        Nicholson J P et al. The role of albumin in critical illness. Br J Anaesth 2000; 85: 599–610.

Impact of anaesthesia on albumin kinetics during major abdominal surgery