Coagulopathy Induced by Hydroxyethyl Starch

Comparing the Effects of 5% Albumin and 6% Hydroxyethyl Starch 130/0.4 (Voluven) on Renal Function as Priming Solutions for Cardiopulmonary Bypass: A Randomized Double Blind Clinical Trial

Background:

The ideal strategy to prime the cardiopulmonary bypass (CPB) circuit in adult cardiac surgery is still a matter of debate.

Objectives:

In this retrospective study, we examined Albumin solution and hydroxyethyl starch (HES) for priming the CPB circuit and evaluated the differences in kidney function and bleeding and coagulation status in the two groups of patients.

Patients and Methods:

Sixty consecutive patients undergoing elective coronary artery bypass grafting were studied. Patients were excluded due to emergency surgery, history of cardiac surgery, history of receiving medication with antiplatelet agents except ASA 80 (mg/day) within the previous five days, preoperative coagulation disorder, left ventricular ejection fraction less than 50%, preoperative renal dysfunction (serum creatinine > 1.4 mg/dL), preoperative hepatic dysfunction (serum aspartate/alanine amino transferase > 60 U/l), preoperative electrolyte imbalance, known hypersensitivity to HES and chronic diuretic therapy. The patients were divided randomly into two groups of HES (n = 30) and Albumin (n = 30). Hemodynamic parameters, serum creatinine concentrations and glomerular filtration rate, PT, PTT and INR were measured. Early bleeding was measured according to the first 24-hour drainage from the tube. Hemodynamics and all laboratory measurements were performed after induction of anesthesia and at the morning of the first, second and third postoperative days in the ICU.

Results:

GFR differences were statistically lower in Albumin group in comparison with Group B at 24, 48 and 72 hours postoperation. Platelet count difference and postoperative bleeding were significantly lower in Albumin group.

Conclusions:

Administration of Albumin compared to HES in patients with a normal renal function results in a lower drop of GFR and platelet count, less bleeding and lower rise of serum creatinine.

The effect of hetastarch 670/0.75 administered in vivo as a constant rate infusion on platelet closure time in the dog

OBJECTIVE

To evaluate the effects of hetastarch 670/0.75 on canine platelet function and clinical bleeding following its administration as a constant rate infusion (CRI) at 1 mL/kg/h and 2 mL/kg/h for 24 hours.

DESIGN

In vivo, prospective, open-label, crossover study.

SETTING

Research laboratory at a university veterinary facility.

ANIMALS

Eight healthy, adult male research dogs.

INTERVENTIONS

Each dog received 1 mL/kg/h hetastarch for 24 hours then 2 mL/kg/h with a washout period of 10 weeks between each experiment. Platelet closure time (CT) was measured using a platelet function analyzer with collagen adenosine diphosphate (ADP) cartridges. CT measurements were performed at baseline and 6, 12, and 24 hours following initiation of hetastarch infusion.

MEASUREMENTS AND MAIN RESULTS

At 1 mL/kg/h, mean CT was significantly increased at the 12- and 24-hour time point relative to the baseline value, although mean CT never rose to a value above the reference interval during the 24-hour infusion. At 2 mL/kg/h, median CT was also significantly increased at the 12- and 24-hour time point relative to the baseline value. Administration of 2 mL/kg/h did progressively prolong the median CT value though only exceeded the reference interval at the 24-hour time point. Despite the prolongation of median CT, there was no clinical evidence of spontaneous bleeding in any dog during the 24-hour infusion at either CRI rate.

CONCLUSIONS

Hetastarch 670/0.75 when used as a 24-hour CRI at 1 and 2 mL/kg/h prolongs CT in healthy dogs at 6, 12, and 24 hours. Median CT only exceeded the reference interval at 24 hours at 2 mL/kg/h.

A Comparative Coagulopathic Study for Treatment of Vasospasm by Using Low- and High-molecular Weight Hydroxyethyl Starches

OBJECTIVE

High-molecular-weight hydroxyethyl starch (HES) compromises blood coagulation more than does low-molecular-weight HES. We compared the effects of low- and high-molecular-weight HES for the treatment of vasospasm and investigated the dose relationship with each other.

METHODS

Retrospectively, in a series of consecutive 102 patients with subarachnoid hemorrhage (SAH), 35 patients developed clinical symptoms of vasospasm of these fourteen patients were treated with low-molecular-weight HES for volume expansion while the other 21 received high-molecular-weight HES as continuous intravenous infusion. Prothrombin time (PT), partial thromboplastin time (PTT), fibrinogen level, and platelet count were all measured prior to initiation, during treatment and after termination of therapy for symptomatic vasospasm. The total dose of HES ranged from 5 L to 14 L and median infusion duration was 10 days.

RESULTS

A more pronounced PTT prolongation was observed in high-molecular-weight HES group compared with low-molecular-weight HES group. No other coagulation parameters were altered. Dosage (=duration) shows a positive correlation with PTT. Clinically, significant bleeding episodes were noted in four patients who received high-molecular-weight HES.

CONCLUSION

Coagulopathy was developed in direct proportion to molecular weight of starch and dosages. We propose the extreme caution in the administration of HES solution for the vasospasm treatment.

Optimizing intraoperative fluid therapy

PURPOSE OF REVIEW

Correcting the fluid status of the surgical patient is an integral part of good anaesthetic practice. There have been few areas in anaesthesia and perioperative medicine as controversial as fluid resuscitation. Uncertainties still exist as to what the best solution to give is, whether it be a colloid or a crystalloid, and how and when to give it. As well as increasing awareness of the different properties of various colloids, there has been interest in the nature of the carrier solutions, essentially a choice between saline or Ringer's lactate (compound sodium lactate or Hartmann's solution). In this article we review recent studies involving crystalloids, the 'new colloids', and on the amount and timing of fluid therapy.

RECENT FINDINGS

Saline based fluids (including most colloids) are associated with a hyperchloremic metabolic acidosis, and a hypocoagulable state, although these may not necessarily harm the patient. Saline may have deleterious effects on renal function. Colloids in solutions similar to Ringer's lactate ('balanced solutions') may avoid these effects although few are currently available. Several studies that have used fluids (along with other therapies) to improve organ perfusion around the time of surgery have been associated with a better outcome.

SUMMARY

Compared with Ringer's lactate, saline, and saline-based colloids are associated with a hyperchloremic metabolic acidosis, and a hypocoagulable state although they may not be associated with adverse patient outcomes. Increasing awareness of the 'Stewart hypothesis' has led to new ways of managing hyperchloremic metabolic acidosis. The 'crystalloid-colloid debate' continues, and has led to an awareness that these different fluids, along with their carrier solutions are drugs with different effects. Several studies, in which patients have received more fluid in the protocol group, have found better clinical outcomes in the 'optimized' patients.

An In Vitro Study Comparing the Effects of Hextend, Hespan, Normal Saline, and Lactated Ringer’s Solution on Thrombelastography and the Activated Partial Thromboplastin Time

OBJECTIVE

The purpose of this study was to determine if 6% HES 450/0.7 (hydroxyethyl starch 450/0.7) in normal saline (Hespan) and 6% HES 450/0.7 in lactated Ringer's solution (Hextend) have the same inhibition of the intrinsic coagulation pathway and platelet function. Multiple studies have suggested that 6% Hespan inhibits coagulation and increases chest tube drainage and transfusion requirements in cardiac surgical patients. There have been few studies of the effects of 6% Hextend, a relatively new plasma volume expander, on coagulation and the results thus far have been mixed.

DESIGN

A prospective in vitro study.

SETTING

A large academic medical center.

PARTICIPANTS

Blood was collected from 30 healthy volunteers. Interventions : The blood was fractionated and diluted by 30% with Hextend, Hespan, normal saline, and lactated Ringer's solutions, with a native sample for a control.

MEASUREMENTS AND MAIN RESULTS

Primary outcome measures were thromboelastography and activated partial thromboplastin time (APTT). For each of the TEG parameters, there was no difference between samples diluted with Hextend compared with Hespan (p > or = 0.112 in all cases). APTT did not differ significantly between samples diluted with Hextend compared with Hespan (p = 0.562).

CONCLUSIONS

This prospective in vitro study suggests that Hextend and Hespan, hydroxyethyl starch 450/0.7 in different base solutions, exhibit the same effect on platelet function as measured by the TEG.

Effect of in vitro hemodilution with hydroxyethyl starch and dextran on the activity of plasma clotting factors

OBJECTIVE

A recent thrombelastography study indicated a compromised in vitro blood coagulation after 10:10 (equal parts of blood and infusion) and 10:4 (10 parts blood to four parts infusion) hemodilution with several plasma substitutes. Oncovertin N (Oncovertin) (a 10% dextran 40 solution) had the strongest anticoagulant effect of all solutions tested, and HAES-sterile 10% (HAES) (a 10% hydroxyethyl starch 200/0.5 solution) showed the strongest effect of five different hydroxyethyl starch preparations. The aim of this study was to determine how in vitro hemodilution with HAES and Oncovertin affects the activity of coagulation factors.

DESIGN

HAES and Oncovertin were tested to determine the intrinsic effect of colloid molecules, as opposed to hemodilution. Normal saline (NaCl) and nonlactated Ringer solution were used as noncolloidal controls.

SETTING

University research institute.

PATIENTS

Six healthy volunteers.

INTERVENTIONS

Twenty milliliters of blood was obtained from each subject.

MEASUREMENTS AND MAIN RESULTS

Prothrombin index, activated partial prothrombin time, soluble fibrin monomers, and the activity of coagulation factors I, II, V, VII, VIII, IX, X, XI, and XII were measured with the Behring Chromotimer according to the manufacturer's instructions. Two dilution ratios of citrated blood to infusion were used: 10:10 (equal parts of blood and infusion) and 10:4 (10 parts blood to four parts infusion). Baseline was undiluted. Hemodilution with NaCl at both 10:4 and 10:10 influenced the coagulation variables measured. The activities of factors I, VII, and soluble fibrin monomers were less influenced than expected by hemodilution alone. The activities of factors II, V, IX, and XI were significantly (p <.04) lower with both 10:4 and 10:10 dilution with NaCl. In the assays for factors IX, XI, and XII, clots formed immediately after adding the appropriate reagents in the presence of Ringer solution at 10:10 hemodilution, so that the activities of those factors could not be measured. For the other factors and for 10:4 dilution, the outcome after Ringer solution was similar to that of NaCl. The activities were less influenced after 10:4 hemodilution with both HAES and Oncovertin than after dilution with NaCl and Ringer solution, with no significant differences from baseline. At 10:10 hemodilution with both HAES and Oncovertin, several factor activities were significantly (p <.04) lower than baseline.

CONCLUSIONS

Both NaCl and Ringer solution cause measurable effects on coagulation factors at 10:4 hemodilution that can be explained by hemodilution alone. The effects on clotting factors of 10:4 hemodilution with HAES and Oncovertin were not significant. Even at 10:10 hemodilution with HAES or Oncovertin, the reduction in factor activities, although significantly (p <.04) different from baseline, was less than what was expected by dilution alone.

[Effects of plasma substitutes on hemostasis]

OBJECTIVE

Data synthesis on haemostasis effects of cristalloids and colloids and clinical implications for their use for plasma volume replacement.

DATA SOURCES

Data were searched in the Medline database from 1954 to 2000 using the following key-words: cristalloids, colloids, albumin, gelatin, dextran, hydroxyethyl starch, haemostasis, von Willebrand disease, haemodilution.

DATA EXTRACTION

Publications from 1954 to 1990 were selected depending on the quality of their methodology. Most of articles published after 1990 and all types including case report were accepted.

DATA SYNTHESIS

Cristalloids induces a moderate hypercoagulable state with 10 to 30% haemodilution. Hypocoagulation is observed above 50% haemodilution. Albumin does not impair hemostasis except with a 50% or more haemodilution where hypocoagulation is observed. Dextran dramatically impairs haemostasis and fibrinolysis. With increasing dose, a progressive decrease of all von Willebrand multimers, mostly the largest, is observed. Till 50% haemodilution, gelatin has a moderate impact on hemostasis, but platelet aggregation is moderately modified. However this moderate impairment of haemostasis may potentiate the haemostatic effect of other colloids when used in association with gelatin. More than 30% haemodilution with hydroxyethyl starch (HES) has a serious effect in vitro on platelet function and fibrinoformation. In most studies in human, less than 20 ml.kg-1 plasma volume replacement has no clinical impact, but in some evaluations postoperative bleeding is more important with HES, particularly HES 450, in comparison to other colloids. With HES 450 and HES 200 highly substituted (0.6 of degree of substitution) intravascular cumulation of large molecules leads to type I von Willebrand syndrome when doses overtake 80 ml.kg-1. Dextran and HES are prohibited in patients with impaired haemostasis due to congenital disease (haemophilia and von Willebrand disease) or acquired defect (thrombocytopenia). Caution is required in patients with renal failure or receiving antithrombotic or non-steroidal anti-inflammatory agents. Patients without a haemorrhagic diathesis must not received more than 1.5 g.kg-1.j-1 of dextran and restrictive conditions of use must be respected with HES.

CONCLUSION

Except isotonic cristalloids, all colloids induce haemostastic changes particularly for haemodilution over 30%. Effects are more pronounced with HES and dextran.

The influence of intravascular volume therapy with a new hydroxyethyl starch preparation (6% HES 130/0.4) on coagulation in patients undergoing major abdominal surgery

A new hydroxyethyl starch (HES) preparation with a mean molecular weight of 130,000 daltons and a degree of substitution of 0.4 shows favorable pharmacokinetic properties. We conducted a study of the influence of the new HES specification on coagulation and compared it with another colloidal intravascular volume replacement regimen using gelatin. According to a prospective, random sequence, 42 patients undergoing major abdominal surgery received either HES 130/0.4 (n = 21) or gelatin (n = 21) until the first postoperative day (POD) to keep central venous pressure between 10 and 14 mm Hg. From arterial blood samples, standard coagulation variables were measured, and modified thrombelastogram (TEG) measurements using different activators were performed. A total of 2830 +/- 350 mL of gelatin and 2430 +/- 310 mL of HES 130/0.4 were administered until the morning of the first POD. The use of allogeneic blood/blood products and standard coagulation variables did not differ significantly between the two groups. After induction of anesthesia, all TEG data for both groups were within normal range. Coagulation time and maximum clot firmness did not change significantly in any TEG measurements during the study period. The kinetics of clot formation (clot formation time) significantly increased immediately after surgery, but without showing significant group differences. On the morning of the first POD, the clot formation time returned to almost normal levels, except for aprotinin-activated TEG(R). We conclude that administration of moderate doses of the new HES 130/0.4 preparation in patients undergoing major abdominal surgery results in similar coagulation alterations as those after using an established gelatin-based volume-replacement regimen.

IMPLICATIONS

We compared the effects of infusion of a new hydroxyethyl starch preparation (6% hydroxyethyl starch; mean molecular weight 130,000 daltons; degree of substitution 0.4) on coagulation with a gelatin-based intravascular volume replacement regimen in patients undergoing major abdominal surgery. After moderate doses of hydroxyethyl starch (2430 +/- 310 mL until the morning of the first postoperative day), coagulation monitoring, including modified thrombelastography, did not show impaired hemostasis.

Randomized trial of hydroxyethyl starch versus gelatine for trauma resuscitation

BACKGROUND

Previous studies have demonstrated the rapid increase in systemic capillary permeability after blunt trauma and its association with poor outcome. There are theoretical advantages in resuscitation with colloid fluids, which are well retained in the vascular compartment during times of capillary leak. The aim of this study was to compare the effects of posttrauma resuscitation with hydroxyethyl starch (HES) (molecular mass, 250 kDa) or gelatine (molecular mass, 30 kDa), the hypothesis being that HES would reduce capillary leak.

METHODS

Forty-five patients suffering blunt trauma were randomized on admission to receive either gelatine (Gelofusine) (n = 21) or HES (Pentaspan) (n = 24) for the first 24 hours, after which the choice of fluid was at the discretion of the clinician. The mean Injury Severity Score for the HES and gelatine groups were 20.0 (range, 9-41) and 18.1 (range, 9-32), respectively (p = 0.43). Capillary permeability was assessed by urine albumin excretion rate for the first 24 hours. For 5 days the daily mean P(O2)/F(IO2) ratio, serum C-reactive protein, hemoglobin, white cell and platelet counts, prothrombin, and activated partial thromboplastin time were recorded.

RESULTS

Capillary permeability was lower in HES-treated patients during the first 24 hours. Log mean (95% confidence interval) albumin excretion rate for gelatine and HES groups at 6 hours were 117.5 (84.9) and 46.8 (24.3) microg/min (p = 0.011), at 12 hours were 54.9 (30.0) and 17.2 (7.6) microg/min (p = 0.001), and at 24 hours were 50.5 (23.4) and 23.6 (16.3) microg/min (p = 0.030), respectively. The mean (95% confidence interval) P(O2)/F(IO2) ratio for the HES and gelatine groups 48 hours after admission were 324 (44) and 267 (43) mm Hg, respectively (p = 0.03). The mean (95% confidence interval) serum C-reactive protein in the HES and gelatine groups 24 hours after admission were 72.4 (19.2) and 105.7 (30.1) mg/L, respectively (p = 0.03). There were no significant differences in any of the hematologic parameters during the first 48 hours.

CONCLUSION

The results suggest that compared with gelatine, resuscitation with HES reduces posttrauma capillary leak.