Repeated quantitative measurements of De Novo synthesis of albumin and fibrinogen

Albumin and fibrinogen synthesis rates in advanced chronic liver disease

Synthesis of plasma proteins is an important function of the liver that has sparsely been investigated by modern techniques in patients with advanced chronic liver disease (CLD). Twenty-eight well-characterized patients with CLD under evaluation for liver transplantation were included. Albumin and fibrinogen synthesis rates were measured by the flooding dose technique using stable isotope-labeled phenylalanine. Transcapillary escape rate of albumin and plasma volume were assessed by radioiodinated human serum albumin. The absolute albumin synthesis rates were low (65 mg/kg/day, range: 32-203) and were associated with impaired liver function, as reflected by the risk-scores Child-Pugh (P = 0.025) and model for end-stage liver disease (rs = -0.62, P = 0.0005). The fibrinogen synthesis rate (12.8 mg/kg/day, range: 2.4-52.9) was also negatively associated with liver function. The synthesis rates of albumin and fibrinogen were positively correlated. Plasma volume was high (51 ± 9 mL/kg body wt), which contributed to an almost normal intravascular albumin mass despite low plasma concentration. Autoimmune inflammatory etiologies to CLD were associated with higher fibrinogen synthesis. De novo synthesis rates of albumin and fibrinogen in advanced chronic liver failure were negatively correlated to prognostic scores of liver disease. Albumin synthesis rate was low and associated with both liver failure and autoimmune inflammation, whereas fibrinogen synthesis was often normal and positively associated with chronic inflammation. This is different from acute inflammatory states in which both albumin and fibrinogen synthesis rates are high.NEW & NOTEWORTHY Albumin and fibrinogen synthesis were positively correlated, but the high variation indicates that these are probably influenced by different mechanisms. There might be a limited metabolic reserve for the liver to increase both albumin and fibrinogen synthesis in response to longstanding inflammation in CLD and fibrinogen seems to be prioritized.

Fibrinogen and albumin synthesis rates in major upper abdominal surgery

Plasma fibrinogen and albumin concentrations initially decrease after abdominal surgery. On postoperative days 3-5 fibrinogen concentration returns to the preoperative level or even higher, while albumin stays low. It is not known if these altered plasma concentrations reflect changes in synthesis rate, utilization, or both. In particular a low albumin plasma concentration has often been attributed to a low synthesis rate, which is not always the case. The objective of this study was to determine fibrinogen and albumin quantitative synthesis rates in patients undergoing major upper abdominal surgery with and without intact liver size. Patients undergoing liver or pancreatic resection (n = 9+6) were studied preoperatively, on postoperative days 1 and 3-5. De novo synthesis of fibrinogen and albumin was determined; in addition, several biomarkers indicative of fibrinogen utilization were monitored. After hemihepatectomy, fibrinogen synthesis was 2-3-fold higher on postoperative day 1 than preoperatively. On postoperative days 3-5 the synthesis level was still higher than preoperatively. Following major liver resections albumin synthesis was not altered postoperatively compared to preoperative values. After pancreatic resection, on postoperative day 1 fibrinogen synthesis was 5-6-fold higher than preoperatively and albumin synthesis 1.5-fold higher. On postoperative days 3-5, synthesis levels returned to preoperative levels. Despite decreases in plasma concentrations, de novo synthesis of fibrinogen was markedly stimulated on postoperative day 1 after both hemihepatectomies and pancreatectomies, while de novo albumin synthesis remained grossly unchanged. The less pronounced changes seen following hepatectomies were possibly related to the loss of liver tissue.

The Risk Factors for Perioperative Serum Albumin Variation in Pediatric Patients Undergoing Major Gastroenterology Surgery

Background: The albumin, a negative acute-phase protein, is important for perioperative morbidity, even in patients with normal preoperative levels. This study intend to determine the perioperative factors related with the postoperative reduction in serum albumin (ΔALB) and its influence on perioperative outcome in a pediatric general surgical cohort.

Methods: This single-center retrospective review included 939 pediatric patients who underwent major gastroenterology surgery from August 2010 to August 2019. The patients were dichotomized into a high ΔALB group (≥14.6%) and a low ΔALB group (<14.6%) based on the mean value of ΔALB (14.6%). the independent risk factors for ΔALB, were explored using the propensity score matching to minimize potential selection bias and subjected to method multivariable logistic regression model. Furthermore, in 366 matched patients, the influences of operating time on perioperative outcomes were analyzed.

Results: Among the 996 patients reviewed, 939 patient records were enrolled in the final analysis. Controlling for other factors, multivariable analysis showed that a high CRP on POD 3 or 4 [odds ratio (OR) = 2.36 (95% CI, 1.51–3.86); p = 0.007], a longer operating time [OR = 1.18 (95% CI, 1.00–1.53); p = 0.014), and the presence of Charcot's triad [OR = 1.73 (95% CI, 1.05–2.83); p = 0.031] were factors that predicted a high ΔALB level. A high ΔALB level was also related with gastrointestinal functional recovery delay, reflected by the postoperative defecation (p = 0.013) and bowel movement (p = 0.019) delay and the high occurrence of postoperative complications (16.1 vs. 10.9%, OR, 1.57; 95% CI, 1.02–2.41, P = 0.0026).

Conclusions: The high ΔALB level was correlated with postoperative outcome. To obtain a safe recovery and discharge after a major abdominal operation, the above risk factors for ΔALB could be addressed in the perioperative period.

Intra- and inter-Individual variability in nerve block duration: A randomized cross-over trial in the common peroneal nerve of healthy volunteers

BACKGROUND

The reported variation in nerve block duration is considerable. To individualize nerve block therapy, knowledge of the intra- vs inter-individual variability is essential. We investigated the relative contribution of these 2 parameters to the overall nerve block duration variability.

METHODS

With ethics committee approval, we conducted a randomized cross-over trial where 20 healthy volunteers received 8 common peroneal nerve blockades with lidocaine 0.5% on 4 consecutive days. Allocations were 5 mL to either the right or left side and 10 mL to the opposite side on day 1 and 2 and vice versa on day 3 and 4. With fixed needle entry and nerve target, we repeated local anaesthetic deposition for each blockade. The primary outcome was variation in duration of sensory nerve block defined as insensitivity to a cold stimulus. Data were analysed using linear mixed model regression.

RESULTS

The mean sensory block duration of 380 (95% CI = [342; 418]) minutes on day one was 55 [33; 77] minutes longer than on day two (P < .001), but there were no differences in mean duration between days 2, 3 and 4. The ratios with 2.5; 97.5 percentiles between inter- and intra-individual variation were 2.4 [0.8; 5.2] for the 5 mL blockades and 3.0 [0.9; 6.7] for the 10 mL blockades. The probabilities of inter- to intra-individual variation-ratios >1 were 96% and 97%.

CONCLUSION

The intra-individual variability is a substantially minor contributor to the overall variability in sensory nerve block duration compared with the inter-individual variability.

Albumin mass balance and kinetics in liver transplantation

Background

In major abdominal surgery albumin is shifted from the circulation, presumably leaking into the interstitial space, contributing to a 30–40% decrease in plasma albumin concentration. During and after liver transplantation exogenous albumin is infused for volume substitution and to maintain plasma albumin concentration. Here we used liver transplantation as a model procedure for the study of albumin mass balance and kinetics during major abdominal surgery with albumin substitution.

Methods

Patients were studied during liver transplantation (n = 16), and until postoperative day 3 (POD 3) (n = 11). Cumulative perioperative albumin shift was assessed by mass balance of albumin and hemoglobin. Synthesis rates of albumin and fibrinogen were estimated by the flooding technique using deuterium-labeled phenylalanine. Albumin distribution was assessed by radioiodinated human serum albumin.

Results

At the end of surgery, 37 ± 17 g of albumin (p < 0.0001) had shifted from plasma, and this amount was stable until POD 3 (48 ± 33 g, p = 0.0017 versus baseline). There was 91 ± 37 g exogenous albumin infused peroperatively and another 47 ± 35 g was infused postoperatively until POD 3. Absolute synthesis rates of albumin and fibrinogen on POD 3 were 239 ± 84 mg/kg body weight/day and 33 mg/kg body weight/day (range 5–161), respectively.

Conclusions

Albumin net leakage from plasma progressed until the end of surgery, and was then unaltered until POD 3. This is in contrast with the normalization of the cumulative albumin shift identified at day 3 after non-transplant major abdominal surgery. Liver synthesis of export proteins was high compared to reference values at the third postoperative day, suggesting rapid recovery of synthesis capacity.

Trial registration

Swedish Medical Product Agency, EudraCT 2015-002568-18. Registered on 15 July 2015.