Recruitment of efferent lymph during infusion of 20 % albumin

BACKGROUND

Intravenous infusion of hyper-oncotic 20 % albumin expands the plasma volume by approximately twice the infused volume. We investigated whether the recruited fluid stems from accelerated flow of efferent lymph, which would add protein to the plasma, or from reversed transcapillary solvent filtration, where the solvent is expected to be low in protein.

METHODS

We analyzed data from 27 intravenous infusions of 20 % albumin (3 mL/kg; approximately 200 mL) over 30 min given to 27 volunteers and patients. Twelve of the volunteers were also given a 5 % solution and served as controls. The pattern of blood hemoglobin, colloid osmotic pressure, and the plasma concentrations of two immunoglobulins (IgG and IgM) were studied over 5 h.

RESULTS

A decrease of the difference between the plasma colloid osmotic pressure and plasma albumin occurred during the infusions and was almost four times greater for 5 % albumin than for 20 % albumin at 40 min (P < 0.0036), which indicates that non-albumin protein enriched the plasma when 20 % was infused. Moreover, the difference between the infusion-derived dilution of the blood plasma based on hemoglobin and the two immunoglobulins amounted to -1.9 % (-6 to +0.2) for 20 % albumin and to -4.4 % (25th-75th percentile range - 8.5 to +0.2) during experiments with 5 % albumin (P < 0.001). This supports that the plasma was enriched by immunoglobulins, probably via the lymph, when 20 % was infused.

CONCLUSIONS

Between half and two-thirds of the extravascular fluid that was recruited during infusion of 20 % albumin in humans consisted of protein-containing fluid consistent with efferent lymph.

Interstitial washdown during crystalloid fluid loading in graded hypovolemia -A retrospective analysis in volunteers

BACKGROUND

"Interstitial washdown" is an edema-preventing mechanism that implies a greater redistribution of interstitial albumin occurs whenever the capillary filtration is increased.

OBJECTIVE

To study the effect of interstitial washdown on fluid distribution in normovolemic and hypovolemic volunteers.

METHODS

Capillary filtration was increased by infusing 25 mL/kg Ringer's acetate intravenously over 30 min 10 male just after withdrawal of 0, 450, and 900 mL of blood. Population volume kinetic analysis was used to assess the effects of washdown and hemorrhage on fluid distribution, using the difference in plasma dilution based on hemoglobin and albumin as biomarker of washdown.

RESULTS

Blood withdrawal during 10-15 min recruited 100-150 mL of fluid of high albumin content to the plasma, which was probably lymph. The albumin recruitment was temporarily reduced during the fluid loading but increased from 40 min post-infusion and was then greater when preceded by hemorrhage. Simulations suggested that interstitial washdown decreased the extravascular fluid volume by 200 mL over 3 h. The plasma volume and urinary excretion both increased by approximately half this amount.

CONCLUSIONS

Blood loss without hypotension probably recruited lymph to the plasma, but interstitial washdown played no major role in determining the distribution of crystalloid fluid after hemorrhage.

[Hypo- and hypernatremia in the intensive care unit : Pitfalls in volume management]

Hypo- and hypernatremias are very frequent in intensive care unit (ICU) patients and are closely related to volume disturbances and volume management in the ICU. They are associated with longer ICU stays and significant increases in mortality. Treating them is more complex than it may initially appear. Hyponatremias are differentiated based on tonicity and volume status. With hypertonic and isotonic hyponatremias, the primary focus of treatment is the underlying hyperglycemia. In case of hypotonic hypovolemic hyponatremia, the condition is treated with balanced crystalloid solutions. In eu-/hypervolemic hypotonic hyponatremias acute treatment with hypertonic saline is necessary. Hypervolemic hypernatremia occurs almost exclusively in ICU patients, often due to infusion of hypertonic solutions. There is little evidence to guide treatment, although hypotonic infusions in conjunction with diuretics may represent a legitimate approach. Great emphasis should be placed on prevention and the infusion of hypertonic solutions should be avoided. Disturbances in plasma sodium concentrations are common, requiring close attention. Exact diagnostic classification needs to be made and volume managed accordingly.

Temperature and flow rate limit the optimal ex-vivo perfusion of the heart - an experimental study

Background

Ex-vivo heart perfusion can be utilized to study a variety of physiologic and molecular pathways in a controlled system outside of the body. It can also be used in clinical settings such as for organ preservation before transplantation. Myocardial oxygen consumption (MVO₂) correlates with energy production in the myocardium and can also be used to determine the balance between the oxygen supply and demand of the perfused heart. This study sought to determine an ex-vivo perfusion rate that matches the metabolic demands of the heart according to different temperatures and solution compositions (with and without the addition of erythrocytes), a flow below which the supply of oxygen is not sufficient to maintain an aerobic state of the perfused heart (“D_CRIT”).

Methods

Under general anesthesia, rat hearts were procured and preserved by perfusing with the University of Wisconsin Belzer machine perfusion system (UW Belzer MPS) solution saturated with 100% O₂. The key elements of this solution include supraphysiological potassium (to stop the heartbeat and reduce the cellular metabolic demand), starch, gluconate and mannitol (to maintain cell wall integrity), glucose (to sustain basal metabolism), and glutathione (to scavenge free radicals). Three groups of rat hearts (n = 7) were randomly allocated to be perfused at 15 °C, 22 °C or 37 °C, at a varying flow index (FI) starting from a minimum of 380 mL/min/100 g to less than 50 mL/min/100 g, decreasing by 50 mL/min/100 g at 10 min intervals while measuring the MVO₂ at each FI. Lactate was measured from coronary sinus samples to determine the onset of tissue hypoxia/anaerobic state.

Results

The D_CRIT at 15 °C was 99.9 ± 4.9 mL/min/100 g; however, at 22 °C and 37 °C we could not reach a D_CRIT. The myocardial oxygen demand could not be met at 22 °C and 37 °C with the maximum FI above 380 mL/min/100 g even when erythrocytes (10% V/V) were added to the solution. At 15 °C, the production of lactate was evident only below the D_CRIT, while at 22 °C lactate production was present at all flow indices.

Conclusions

Determining the D_CRIT for optimal ex-vivo perfusion of the heart is necessary to ensure adequate tissue oxygenation and limit anaerobic state. Temperatures employed above 15 °C limit the efficient ex-vivo perfusion preservation of heart with the UW Belzer MPS solution.

[A survey of fluid therapy in 2 intensive care units]

To explore the present status of fluid therapy and clinical outcome in critically ill patients in intensive care units (ICU). ICU patients consecutively admitted to our ICU were prospectively enrolled. Patients' demographics, laboratory data, fluid record and clinical outcome were collected. Fluid intake quantity of all patients was at peak on the fifth day which was 2 806 (1 997, 3 582) ml. From the fourth day in ICU, fluid balance started to benegative as -84 (-1 127, 612) ml and gradually increased. Crystalloid solution was the main components. For treatment purposes, medication injections and nutrients were major fluids. Positive correlations were found between total fluid intake quantity, total crystalloid volume, total colloidal volume and hospital stay, ICU stay, duration of intubation (r values as 0.211, 0.686, 0.282, 0.155, 0.506, 0.174, 0.209, 0.072, 0.292, respectively P<0.05). Moreover, positive correlations were also demonstrated between total colloidal volume and total bilirubin, direct bilirubin, alanine transaminase, aspartate transaminase, blood urea nitrogen, serum creatinine (r values as 0.196, 0.242, 0.190, 0.335, 0.284, 0.223, respectively P<0.05).

The Effect of Intraoperative Restricted Normal Saline during Orthotopic Liver Transplantation on Amount of Administered Sodium Bicarbonate

BACKGROUND

Severe metabolic acidosis occurs during orthotopic liver transplantation (OLT) particularly during the anhepatic phase. Although NaHCO3 is considered as the current standard therapy, there are numerous adverse effects. The aim of this study was to determine whether the restricted use of normal saline during anesthesia could reduce the need for NaHCO3.

METHODS

In this study we enrolled 75 patients with end-stage liver disease who underwent OLT from February 2010 until September 2010 at the Shiraz Organ Transplantation Center. Fluid management of two different transplant anesthetics were compared. The effect of restricted normal saline fluid was compared with non-restricted normal saline fluid on hemodynamic and acid-base parameters at three times during OLT: after the skin incision (T1), 15 min before reperfusion (T2), and 5 min after reperfusion (T3).

RESULTS

There were no significant differences in demographic characteristics of the donors and recipients (P>0.05). In the restricted normal saline group there was significantly lower central venous pressure (CVP) than in the non-restricted normal saline group (P=0.002). No significant differences were noted in the other hemodynamic parameters between the two groups (P>0.05). In the non-restricted normal saline group arterial blood pH (P=0.01) and HCO3 (P=0.0001) were significantly less than the restricted normal saline group. The NaHCO3 requirement before reperfusion was significantly more than with the restricted normal saline group (P=0.001).

CONCLUSION

Restricted normal saline administration during OLT reduced the severity of metabolic acidosis and the need for NaHCO3 during the anhepatic phase.

TRIAL REGISTRATION NUMBER

IRCT2013110711662N5.

The effect of intraoperative colloid solutions coadministered with 6% hydroxyethyl starch (130/0.4) on platelet function in patients undergoing total intravenous anesthesia

BACKGROUND

Colloid solutions are used to treat hypovolemia and expanding plasma, but they may inhibit platelet function and reduce the level of coagulation factors during surgery. This study was conducted to compare the effects of hydroxyethyl starch (HES) on adenosine diphosphate (ADP)- and collagen-induced platelet aggregation in patients undergoing total intravenous anesthesia.

METHODS

Patients undergoing endoscopic sinus surgery under total intravenous anesthesia with propofol and remifentanil were divided into a group that underwent fluid management with only crystalloid solution (n = 15) and a group that was managed with crystalloid solution that included 6% HES (130/0.4) (n = 15). ADP- and collagen-induced platelet aggregation were measured 5 minutes before induction, after the first intraoperative hour, and one hour postoperatively.

RESULTS

Significantly diminished ADP- and collagen-induced aggregation values were observed intraoperatively when compared with the preoperative value in the patients that were managed with colloid solution that included HES. In addition, significantly diminished collagen-induced aggregation values were observed intraoperatively when compared with the preoperative value in the group that was managed with the solution that only contained the crystalloid. However, ADP- and collagen-induced platelet aggregation were recovered postoperatively in both groups.

CONCLUSIONS

The results of this study indicated that fluid therapy with colloid solution that contained 6% HES (130/0.4) may diminish ADP-induced platelet aggregation intraoperatively in patients subjected to total intravenous anesthesia.