Influence of fluid therapy on the haemostatic system of intensive care patients

Understanding, assessing and treating immune, endothelial and haemostasis dysfunctions in bacterial sepsis

The interplay between the immune system, coagulation, and endothelium is critical in regulating the host response to infection. However, in sepsis and other critical illnesses, a dysregulated immune response can lead to excessive alterations in these mechanisms, resulting in coagulopathy, endothelial dysfunction, and multi-organ dysfunction. This review aims to provide a comprehensive analysis of the pathophysiological mechanisms that govern the complex interplay between immune dysfunction, endothelial dysfunction, and coagulation in sepsis. It emphasises clinical significance, evaluation methods, and potential therapeutic interventions. Understanding these mechanisms is essential for developing effective treatments that can modulate the immune response, mitigate thrombosis, restore endothelial function, and ultimately improve patient survival.

Comparison of two apheresis systems for granulocyte collection without hydroxyethyl starch

BACKGROUND AND OBJECTIVES

Granulocyte transfusion (GTX) is a treatment option for severe infections in patients with neutropenia. In previous studies, hydroxyethyl starch (HES) was used to enhance red blood cell sedimentation for granulocyte collection (GC). However, there are safety concerns about HES, and HES is not readily available in some countries. Therefore, we compared the granulocyte counts and GC efficiency achieved by two apheresis systems without HES.

MATERIALS AND METHODS

All consecutive GC procedures performed between July 2011 and March 2018 at our hospital were analysed. COBE Spectra was used until 5 February 2016, and Spectra Optia was used afterwards. HES was not used.

RESULTS

Twenty-six GC procedures were performed, including 18 performed using COBE Spectra and 8 using Spectra Optia. When Spectra Optia was used, >1 × 1010 neutrophils were collected from seven of the eight (88%) procedures. Although there was no significant difference in the granulocyte yield between COBE Spectra-based and Spectra Optia-based GC procedures, the collection efficiency of Spectra Optia was significantly higher than that of COBE Spectra (p = 0.021). Furthermore, the granulocyte yields of Spectra Optia-based GC tended to be more strongly correlated with the peripheral blood neutrophil count on the day of apheresis than those of COBE Spectra-based GC.

CONCLUSION

Our results suggest that Spectra Optia achieves greater GC efficiency than COBE Spectra, even without HES. GTX may be a therapeutic option for severe neutropenia, even in places where HES is not available.

"COAGULATION": a mnemonic device for treating coagulation disorders following traumatic brain injury-a narrative-based method in the intensive care unit

Introduction

Coagulopathy associated with isolated traumatic brain injury (C-iTBI) is a frequent complication associated with poor outcomes, primarily due to its role in the development or progression of haemorrhagic brain lesions. The independent risk factors for its onset are age, severity of traumatic brain injury (TBI), volume of fluids administered during resuscitation, and pre-injury use of antithrombotic drugs. Although the pathophysiology of C-iTBI has not been fully elucidated, two distinct stages have been identified: an initial hypocoagulable phase that begins within the first 24 h, dominated by platelet dysfunction and hyperfibrinolysis, followed by a hypercoagulable state that generally starts 72 h after the trauma. The aim of this study was to design an acronym as a mnemonic device to provide clinicians with an auxiliary tool in the treatment of this complication.

Methods

A narrative analysis was performed in which intensive care physicians were asked to list the key factors related to C-iTBI. The initial sample was comprised of 33 respondents. Respondents who were not physicians, not currently working in or with experience in coagulopathy were excluded. Interviews were conducted for a month until the sample was saturated. Each participant was asked a single question: Can you identify a factor associated with coagulopathy in patients with TBI? Factors identified by respondents were then submitted to a quality check based on published studies and proven evidence. Because all the factors identified had strong support in the literature, none was eliminated. An acronym was then developed to create the mnemonic device.

Results and conclusion

Eleven factors were identified: cerebral computed tomography, oral anticoagulant & antiplatelet use, arterial blood pressure (Hypotension), goal-directed haemostatic therapy, use fluids cautiously, low calcium levels, anaemia-transfusion, temperature, international normalised ratio (INR), oral antithrombotic reversal, normal acid-base status, forming the acronym "Coagulation." This acronym is a simple mnemonic device, easy to apply for anyone facing the challenge of treating patients of moderate or severe TBI on a daily basis.

A prospective randomized open-label trial on the comparative effects of 6% hydroxyethyl starch 130/0.4 versus polyionic isotonic crystalloids on coagulation parameters in dogs with spontaneous hemoperitoneum

OBJECTIVE

To evaluate the effects of 6% hydroxyethyl starch 130/0.4 (HES) and a polyionic isotonic crystalloid (CRYS) on standard coagulation tests and rotational thromboelastometry (ROTEM) in dogs with spontaneous hemoperitoneum (SHP).

DESIGN

Prospective randomized open-label clinical study.

SETTING

University teaching hospital.

ANIMALS

Forty-two client-owned dogs presented with SHP.

INTERVENTIONS

Dogs diagnosed with SHP and hypovolemic shock were randomly allocated to receive HES (10 mL/kg, n = 22) or CRYS (30 mL/kg, n = 20) intravenously over 20 minutes for hemodynamic stabilization.

MEASUREMENTS AND MAIN RESULTS

Parameters measured before (T₀ ) and after (T₁ ) treatment were HCT, platelet counts, prothrombin time, activated partial thromboplastin time, fibrinogen concentrations, and extrinsic activated (EXTEM), intrinsic activated (INTEM), and extrinsic activated with platelet inhibition ROTEM assays. Data were analyzed as absolute values and as the percentage change from T₀ to T₁ . No significant differences between groups were detected in any variable at T₀ , and for HCT, platelet counts, prothrombin time, activated thromboplastin time, and fibrinogen concentrations at T₁ . Clot formation time in EXTEM was significantly prolonged (P = 0.037), and maximum clot firmness was significantly decreased (P = 0.038) in the HES group compared to the CRYS group at T₁ . The percentage change in EXTEM clotting time (P = 0.012) and INTEM clot formation time (P = 0.031) was greater after HES than CRYS. Lysis indices remained at 100% for all ROTEM assays in both groups.

CONCLUSION

Compared to a 3-fold volume of CRYS, administration of HES was associated with impairment in ROTEM parameters in dogs with SHP, but no evidence of hyperfibrinolysis was detected.

Effects of Dextran-70 and Albumin on Coagulation in Experimental Hemorrhage in the Guinea Pig

Background:

Dextran-70 is a more potent plasma volume expander than albumin but use has been hampered because of its antithrombotic properties. However, also albumin has antithrombotic properties and little is known about relative effects of these two colloids on coagulation in vivo when controlling for differences in efficacy as plasma volume expanders.

Aim:

Compare effects of dextran-70 and albumin on coagulation at a dose resulting in equal plasma volume expansion.

Methods:

Guinea pigs were subjected to a 25 mL/kg hemorrhage during 20 min and randomized to resuscitation with either 6% dextran-70 at a dose of 15 mL/kg or 5% albumin at a dose of 25 mL/kg (n = 14 in each group) during 30 min starting 1 h of shock. Blood samples were collected at the completion of resuscitation and at 4 h. Plasma volume was measured using ¹²⁵I-albumin and the effect on coagulation was evaluated using whole blood thrombelastography (TEG), measurement of plasma fibrinogen and von Willebrand factor (vWF) concentrations and vWF glycoprotein 1b (GP1b) A activity.

Results:

Plasma volumes after resuscitation were similar in the groups at both time points. Dextran-70 resulted in a transient prolongation of TEG clot amplification time (K) at the completion of resuscitation compared with albumin. TEG clot initiation (R) and strength (MA) did not differ between the treatments at any of the time points. Albumin reduced vWF concentrations to a larger extent than dextran at both time points, whereas no difference in vWF GP1bA activity or in plasma fibrinogen and could be detected.

Conclusion:

In equipotent doses with regard to plasma volume expansion, dextran-70 transiently prolongs clot amplification time more than albumin whereas dextran-70 reduces plasma vWF concentrations less than albumin.

Anaemia and red blood cell transfusion in intracranial neurosurgery: a comprehensive review

Both anaemia and blood transfusion are associated with poor outcomes in the neurosurgical population. Based on the available literature, the optimal haemoglobin concentration for neurologically injured patients appears to be in the range of 9.0-10.0 g dl^-1, although the individual risks and benefits should be weighed. Several perioperative blood conservation strategies have been used successfully in neurosurgery, including correction of anaemia and coagulopathy, use of antifibrinolytics, and intraoperative cell salvage. Avoidance of non-steroidal anti-inflammatory drugs and starch-containing solutions is recommended given the potential for platelet dysfunction.

Comparison of the effects of a balanced crystalloid-based and a saline-based tetrastarch solution on canine whole blood coagulation and platelet function

OBJECTIVE

To evaluate the effects of a 6% hydroxyethyl starch (130/0.42) solution in either a buffered, electrolyte-balanced (HES-BAL), or a saline (HES-SAL) carrier solution on canine platelet function and whole blood coagulation.

DESIGN

Prospective, randomized study.

SETTING

University teaching hospital.

ANIMALS

Thirty-seven client-owned dogs undergoing general anesthesia for arthroscopy or imaging studies.

INTERVENTIONS

Dogs received a 15 mL/kg intravenous bolus of HES-SAL (n = 13), HES-BAL (n = 14), or a modified Ringer's solution (n = 10) over 30-40 minutes. Coagulation was analyzed using a Platelet Function Analyzer-100 (closure time [Ct_PFA ]), and whole blood thromboelastometry (ROTEM) with extrinsically (ex-tem and fib-tem) and intrinsically (in-tem) activated assays, which assessed clotting time (CT), clot formation time (CFT), maximal clot firmness (MCF), and lysis index (LI). Coagulation samples were assayed prior to fluid administration (T0), and 5 minutes (T1), and 3 hours (T2) following fluid bolus administration, respectively.

RESULTS

Both HES solutions resulted in impaired platelet function as indicated by a significant prolongation of Ct_PFA at T1 as compared to T0, but which resolved by T2. An IV bolus of Ringer's solution did not alter platelet function. In both HES groups, whole blood coagulation was significantly impaired at T1 as indicated by a significant increase in in-tem CFT, and a significant decrease in ex-tem, in-tem, and fib-tem MCF compared to T0. Furthermore, a significant increase in ex-tem CFT at T1 compared to T0 was found in the HES-SAL group. With the exception of in-tem MCF after HES-BAL, these effects were not present at T2. No significant differences were found in Ct_PFA or any ROTEM variable at any time point between HES-SAL and HES-BAL.

CONCLUSION

Administration of a single bolus of 15 mL/kg 6% HES 130/0.42 results in significant but short-lived impairment of canine platelet function and whole blood coagulation, regardless of carrier solution.

Effects of hydroxyethyl starch 6 % (130/0.4) on blood loss during cesarean delivery: a propensity-matched analysis

BACKGROUND

Hydroxyethyl starch is commonly used in the obstetric patient population to prevent hypotension during cesarean delivery. Evidence suggests hetastarch is associated with a dysfunction in coagulation cascade. We hypothesized that hetastarch use to prevent spinal hypotension during cesarean delivery would be associated with an increase in blood loss when compared to crystalloid use.

METHODS

We performed a retrospective review of patients who underwent elective cesarean delivery under spinal anesthesia at the University of Virginia between 2011 and 2014. Data from 819 patients was used. Blood loss was the primary outcome. Propensity score-matching was used to match patients who received hetastarch (treatment group) with those who did not receive hetastarch (control group).

RESULTS

Genetic matching resulted in 196 patients in the hetastarch group and 182 patients in the control group. There was no difference in estimated blood loss (p = 0.068), calculated blood loss (p = 0.720), total intraoperative fluid intake (p = 0.289), urine output (p = 0.421), Apgar 1 min (p = 0.830), Apgar 5 min (p = 0.138), phenylephrine consumption (p = 0.742), postoperative day 1 (POD1) hematocrit (p = 0.070) and POD1 platelets (p = 0.233). However, there was a statistically significant difference (but clinically irrelevant) in hematocrit difference between the day of admission and POD1 (mean difference 0.47, p = 0.024), and ephedrine consumption (mean difference 2 mg, p = 0.017) in favor of the control group.

CONCLUSIONS

Our study did not find an association between increased perioperative blood loss and hetastarch use in patients presenting for elective cesarean delivery.

Fluids and coagulation

PURPOSE OF REVIEW

Infusion therapy is essential in intravascular hypovolaemia and extravascular fluid deficits. Crystalloidal fluids and colloidal volume replacement affect blood coagulation when infused intravenously. The question remains if this side-effect of infusion therapy is clinically relevant in patients with and without bleeding manifestations, and if fluid-induced coagulopathy is a risk factor for anaemia, blood transfusion, and mortality, and a driver for resource use and costs.

RECENT FINDINGS

Pathomechanisms of dilutional coagulopathy and evidence for its clinical relevance in perioperative and critically ill patients are reviewed. Furthermore, the article discusses medicolegal aspects.

SUMMARY

The dose-dependent risk of dilutional coagulopathy differs between colloids (dextran > hetastarch > pentastarch > tetrastarch, gelatins > albumin). Risk awareness includes monitoring for early signs of side-effects. With rotational thromboelastometry/thrombelastography, the deterioration not only in clot strength but also in clot formation and in platelet interaction can be assessed. Fibrinogen concentrate administration may be considered in severe bleeding as well as relevant dilutional coagulopathy. Targeted doses of gelatins and tetrastarches seem to have no proven adverse effect on anaemia and allogeneic blood transfusions. Further studies are needed.

Low dose of hydroxyethyl starch impairs clot formation as assessed by viscoelastic devices

OBJECTIVE

High doses of the synthetic colloid hydroxyethyl starch (HES) used for plasma expansion have been associated with impaired haemostasis and hypocoagulation. Less is known about effects on clot formation in the low haemodilutional range (< 40%). This study evaluated the effects of low haemodilution with HES and albumin on coagulation using two different viscoelastic methods.

METHODS

Clot formation was studied in vitro in healthy donor blood after 10% and 30% haemodilution with 60 g/L HES 130/0.4 or 50 g/L albumin with free oscillation rheometry (FOR) and rotational thromboelastography.

RESULTS

Clotting time was not significantly affected at 10% haemodilution but was prolonged with both substances at 30% dilution (p < 0.01-0.001). The effect was significantly more pronounced with HES than with albumin. The elasticity of the clot was slightly reduced at 10% dilution with albumin, more pronounced at 10% dilution with HES (p < 0.05), further reduced at 30% dilution with albumin and to a still greater extent at 30% dilution with HES (p < 0.05). With albumin the functional activity of fibrinogen was not reduced in excess of the dilutional effect. HES in contrast produced a further reduction in clot elasticity than caused by mere dilution at both 10% and 30% dilutions (p < 0.001).

CONCLUSIONS

There is an adverse effect on clot formation even at low grade haemodilution with both albumin and HES. The effect on coagulation is significantly more pronounced with HES than with albumin.

Management of hemorrhage in trauma

Hemorrhage remains one of the leading causes of trauma-related deaths. Uncontrolled diffuse microvascular bleeding in the course of initial care is common, potentially resulting in exsanguination. Early and aggressive hemostatic intervention increases survival and reduces the incidence of massive transfusion. Thus, timely diagnosis of the underlying coagulation disorders is mandatory. It has been shown that standard coagulation tests do not sufficiently characterize trauma-induced coagulopathy (TIC). This has led to increasing interest in alternatives, such as the viscoelastic test, to diagnose TIC and to provide the basis for a goal-directed hemostatic therapy. The concept of damage control resuscitation (DCR) has been introduced widely in trauma patients with severe bleeding. This strategy addresses important confounders of the coagulation process such as hemodilution, hypothermia, and acidosis; DCR is based on a damage control surgical approach, permissive hypotension, and improvement of hemostatic competence. Many studies have shown benefit in mortality when using high ratios of fresh frozen plasma (FFP) to red blood cells (RBC) as early treatment. However, there is increased awareness that coagulation factor concentrate could be beneficial in the treatment of trauma-induced coagulopathy.

Impact of different types of resuscitation fluids on coagulation and continuous venovenous hemofiltration hemocompatibility in a porcine model

Intensive therapy demanding diseases (organ failure or sepsis) are assumed to be the etiology behind a decreased biocompatibility of extracorporeal systems for renal replacement therapy (RRT). There are also potential interactions between different components of the overall therapy. Volume substitutes are known to influence hemorheology and coagulation. To define a potential net effect of volume substitutes on the hemocompatibility of an RRT, we chose an animal model without interfering pathophysiologies. According to the problem of early filter failure and coagulation disorders in critically ill patients, we focused on the hypothesized interaction between RRT and different volume substitutes with respect to blood cell counts, coagulation parameters and required heparin dose. Forty-eight pigs were assigned to four groups of fluid therapy with either normal saline (NaCl), 6%HES130kD/0.4 (HES130), 6%HES200kD/0.5 (HES200) or 4%gelatin (GEL). Six pigs of each fluid group underwent continuous venovenous hemofiltration (CVVH), the remaining six served as the control group. Anticoagulation was performed with continuous heparin infusion. CVVH was run in a recirculation-mode for 4.5 h to force hemocompatibility reactions, thereafter in a standard-mode for 2 h. During the CVVH-treatment GEL reduced platelet counts and fibrinogen concentration and additionally lowered ATIII levels. Heparin requirements did not differ between different volume substitutes or CVVH and control groups. Severe pathophysiologies are not the only reason for a reduced hemocompatibility of CVVH treatment. Interaction of a particular volume substitute with CVVH should be considered when interpreting study results and evolving new strategies.

Colloids in sepsis: evenly distributed molecules surrounded by uneven questions

Colloids are frequently used for fluid expansion in the intensive care unit, although its use on several clinical scenarios remains unproven of any relevant clinical benefit. The purpose of this article was to carry out a narrative review regarding the safety and efficacy of colloids in patients with sepsis and septic shock, with emphasis on the most commonly used colloids, albumin and starches. Colloids are effective fluid expanders and are able to restore the hemodynamic profile with less total volume than crystalloids. These properties appear to be preserved even in patients with sepsis with increased capillary permeability. However, some colloids are associated with renal impairment and coagulation abnormalities. Starch use was associated with increased mortality in two large clinical trials. Also, starches probably have significant renal adverse effects and may be related to more need for renal replacement therapy in severe sepsis. Albumin is the only colloid that has been shown safe in patients with sepsis and that may be associated with improved outcomes on specific subpopulations. No trial so far found any robust clinical end point favoring colloid use in patients with sepsis. Because there is no proven benefit of the use of most colloids in patients with sepsis, its use should not be encouraged outside clinical trials. Albumin is the only colloid solution that has proven to be safe, and its use may be considered on hypoalbuminemic patients with sepsis. Nevertheless, there are no robust data to recommend routine albumin administration in sepsis. Starch use should be avoided in patients with sepsis because of the recent findings of a multicenter randomized study until further evidence is available.

Assessment of hemostatic changes after crystalloid and colloid fluid preloading in trauma patients using standard coagulation parameters and thromboelastography

Background:

The choice of an ideal fluid administered post trauma and its subsequent influence on coagulation still poses a clinical dilemma. Hence, this study was designed to assess the influence of in vivo hemodilution with various fluid preparations (4% gelatin, 6% hydoxyethyl starch (HES), Ringer's lactate, 0.9% normal saline) on coagulation using standard coagulation parameters and real-time thromboelastography (TEG) in patients undergoing elective surgery post trauma.

Methods:

In a randomized, double-blind study, 100 patients of either sex and age, belonging to ASA Grades I and II, scheduled for elective surgeries were allocated into four groups of 25 each according to the type of fluid infused. Group G (4% gelatin), Group N (0.9% normal saline), Group R (Ringer's lactate), and Group H (6% HES) received preloading with 1 L of fluid according to the group. The coagulation status of the patients was assessed during perioperative period (before surgery, after fluid preloading, and at the end of the surgery) using both conventional coagulation analysis and TEG.

Statistical Analysis:

Analysis of variance (ANOVA), post hoc and Pearson Chi-square test were used.

Results:

In all the patients preloaded with gelatin, there was a significant increase in prothrombin time index (PTI; 14.88±0.90 vs. 13.78±3.01, P<0.001) and international normalized ratio (INR; 1.12±0.09 vs. 1.09±0.19, P<0.05) compared to the baseline value. An increase was observed in these parameters in the postoperative period also. In the HES group, there was statistically significant increase in PT time (15.70±1.51 vs. 13.74±0.75, P=0.01) and INR (1.20±0.15 vs. 1.03±0.17, P<0.001) as compared to the baseline. In the intergroup comparisons, the patients preloaded with HES had a significant increase in INR (1.20±0.15 vs. 1.12±0.09, P=0.04) and reaction time (R time; 6.84±2.55 min vs. 4.79±1.77 min, P=0.02) as compared to the gelatin group. The fall in coagulation time (k time; 2.16±0.98 vs. 3.94±2.6, P=0.02), rise in maximum amplitude (MA; 61.94±14.08 vs. 50.11±14.10, P=0.04), and rise in A20 (56.17±14.66 vs. 43.11±14.24, P=0.05) were more in patients preloaded with RL as compared to the HES group. 100% patients in the gelatin group, 84.2% patients in the NS group, 94.4% patients in the RL group, and 66.7% patients in the HES group had hypocoagulable (R time > 14 min) state in the postoperative period.

Conclusion:

Crystalloids are optimal volume expanders in trauma, with RL having beneficial effects on coagulation system (decrease in k time and increase in MA and A20). Among the colloids, HES 6% (130/0.4) affects coagulation parameters (increase in PTI, INR, R time, k time) more than gelatin. Trial registration (protocol number-IEC/NP-189/2011).

Effect of rapid fluid resuscitation using crystalloids or colloids on hemostasis in piglets

BACKGROUND AND OBJECTIVES

Impairment of blood coagulation is one of the main side effects of volume replacement, particularly if artificial colloids such as hydroxyethyl starch (HES) and gelatine preparations are used. This animal study aimed to evaluate the effect of a single fast intravenous crystalloid or colloid fluid bolus on blood coagulation as measured by rotation thromboelastometry (ROTEM).

METHODS

Thirty-two anesthetized piglets were infused with a rapid 20 ml·kg(-1) fluid bolus of either normal saline (NS), 4% gelatine, 5% albumin or 6% HES 130/0.4 (n = 8 per group) over a period of 2 min. Hemostasis was assessed by ROTEM before and 1 min after fluid administration. Within-group differences were analyzed by Wilcoxon test, and additionally overall Kruskal-Wallis test followed by posthoc Mann-Whitney U-test were applied to detect differences between groups.

RESULTS

All fluids caused a significant weakening of clot strength within groups. HES and gelatine showed a significantly stronger impairment of clot growth and maximum clot firmness as compared with albumin and normal saline. Impairment of fibrin polymerization was more pronounced following HES as compared with all other fluids.

CONCLUSION

After moderate but very fast volume loading, HES and gelatine impair blood coagulation to a larger extent as compared with albumin or normal saline, while no significant differences were observed between both artificial colloids.

Influence of hydroxyethyl starch (HES) 130/0.4 on hemostasis as measured by viscoelastic device analysis: a systematic review

PURPOSE

Hydroxyethyl starch solutions (HES) are plasma volume expanders which affect hemostasis. Newer HES 130/0.4 is said to be safer. Reevaluation of published evidence is necessary after the recent retraction of studies.

METHODS

Systematic review of studies assessing HES 130/0.4 effects on hemostasis by thrombelastography (TEG, ROTEM) or Sonoclot (SCR) in comparison with crystalloid or albumin control fluids was performed. Only studies which provided statistical comparisons between study fluids were analyzed. Studies were divided into in vitro or in vivo hemodilution studies. We assessed study quality, HES effects which differed significantly from controls, values outside normal range, degree of hemodilution, and cumulative HES dose.

RESULTS

Seventeen in vitro and seven in vivo hemodilution studies were analyzed. Four studies reported quality control measures. Nineteen studies (all 15 ROTEM studies, 3 of 5 in vitro TEG, and 1 of 2 SCR studies) showed a significant hypocoagulatory effect of HES 130/0.4 on clot formation, while clotting time was not uniformly affected. Three in vivo TEG studies with low HES doses or cancer patients found mixed or nonsignificant results. In studies which provided normal ranges (n = 9), more values were outside normal ranges in the HES than in the control groups (87/122 vs. 58/122, p < 0.001). Dose effects were apparent in the in vitro studies, which investigated higher dilutions up to 80%. In vivo studies were fewer and did not investigate doses >40 ml/kg.

CONCLUSIONS

HES 130/0.4 administration results in a weaker and smaller clot. Until results from well-designed clinical trials are available, safer fluids should be chosen for patients with impaired coagulation.