A randomized, blinded trial comparing the hemostatic effects of pentastarch versus hetastarch

The effects of hydroxyethyl starch 130/0.4 on perioperative renal function in patients undergoing cardiac surgery: A randomised controlled trial

Background

Acute kidney injury (AKI) after cardiac surgery increases the risk of morbidity and mortality. Hydroxyethyl starch (HES) is often used during surgery due to its plasma-volume expanding effect, but the impact of HES 130/0.4 on renal function in patients undergoing cardiac surgery remains unclear. The aim of our study is to investigate the impact of HES 130/0.4 on postoperative renal function in patients undergoing cardiac surgery using cardiopulmonary bypass.

Methods

Our study was a randomised, single-center, single-blind study conducted on 60 adult patients who underwent cardiac surgery using cardiopulmonary bypass: 30 patients were intraoperatively administered with HES 130/0.4; the other 30 with Ringer's bicarbonate. The primary endpoints were occurrence of AKI within 30 days of surgery and the disease stages.

Results

The mean dose of 6% HES 130/0.4 was 28 ml/kg. AKI occurred within 30 days of the operation in 8 cases (28.6%) in the HES group and 6 cases (21.4%) in the crystalloid group (no significance: p = 0.5371). Disease stages were as follows: “no AKI”, “stage 1”, “stage 2″ and “stage 3″, accounting for 20 cases (71.5%), 6 cases (21,4%), 2 cases (7.1%), and 0 cases, respectively, in the HES group, and 22 cases (78.6%), 6 cases (21.4%), 0 cases, and 0 cases, respectively, in the crystalloid group (no significance: p = 0.3508).

Conclusion

There was no significant difference in the occurrences or stages of AKI during the 30 days following cardiac surgery with cardiopulmonary bypass between patients administered with HES 130/0.4 or Ringer's bicarbonate.

•

Hydroxyethyl starch 130/0.4 is an effective plasma-volume expander.

•

Hydroxyethyl starch has a potential renal toxicity in cardiac surgery.

•

Acute kidney injury after cardiac surgery increases the risk of mortality.

•

Administration of hydroxyethyl starch 130/0.4 or crystalloid in cardiac surgery.

•

No difference in the occurrences or stages of acute kidney injury between groups.

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.

Resuscitation Strategies for the Small Animal Trauma Patient

Traumatic injuries in small animals are a common cause for presentation to emergency departments. Severe traumatic injury results in a multitude of systemic responses, which can exacerbate initial tissue damage. Trauma resuscitation should focus on the global goals of controlling hemorrhage, improving tissue hypoperfusion, and minimizing ongoing inflammation and morbidity through the concept of "damage-control resuscitation." This approach focuses on the balanced use of blood products, hemorrhage control, and minimizing aggressive crystalloid use. Although these tenets may not be directly applicable to every veterinary patient with trauma, they provide guidance when managing the most severely injured subpopulation of these patients.

Postoperative Blood Loss and Coagulation Changes After Balanced 6% Hydroxyethyl Starch 130/0.4 Administration During Spine Surgery: A Retrospective Study

STUDY DESIGN

Retrospective analysis.

OBJECTIVE

The objective of this study was to investigate the effects of intraoperative balanced 6% hydroxyethyl starch (HES) 130/0.4 on postoperative blood loss and the coagulation profile.

SUMMARY OF BACKGROUND DATA

The safety of colloid versus crystalloid transfusion for bleeding and coagulation during major spine surgery remains controversial and only a few studies exist. Thus, we compared the effects of balanced 6% HES 130/0.4 and crystalloid on postoperative bleeding and coagulation.

METHODS

Patients undergoing spine surgery between February 1, 2015 and February 28, 2017 were divided into 2 groups: patients receiving intraoperative balanced 6% HES 130/0.4 and patients receiving crystalloid. We compared the postoperative bleeding volume with changes in the coagulation profile and length of hospital stay between these 2 groups. Propensity score (PS)-matching and multivariate stepwise linear regression were performed.

RESULTS

A total of 169 patients who met the inclusion criteria were analyzed. The quantity of total colloid per patient was 10-15 mL/kg. A significant difference was observed in the total intraoperative transfused crystalloid volume between the 2 groups (colloid group, 1.394.6±1.414.0 mL; crystalloid group, 2.027.3±1.114.1 mL; P<0.001). Postoperative blood loss and coagulation profile changes were not significantly different in the 60 PS-matched paired patients. Furthermore, no differences in either postoperative transfusion requirement or length of hospital stay were observed between the groups. Multivariate stepwise linear regression revealed that operation time (β=0.549; P<0.001) and intraoperative transfusion of packed red blood cells (β=0.466; P=0.003) or fresh frozen plasma (β=-0.263; P=0.041) were independently associated with postoperative blood loss. However, intraoperative colloid administration was not a predictive factor.

CONCLUSIONS

Intraoperative infusion of balanced 6% HES 130/0.4 in patients undergoing spine surgery presented clinically insignificant changes in postoperative blood loss and coagulation compared to crystalloid.

LEVEL OF EVIDENCE

Level III.

Considerations in Fluids and Electrolytes After Traumatic Brain Injury

Appropriate fluid management of patients with traumatic brain injury (TBI) presents a challenge for many clinicians. Many of these patients may receive osmotic diuretics for the treatment of increased intracranial pressure or develop sodium disturbances, which act to alter fluid balance. However, establishment of fluid balance is extremely important for improving patient outcomes after neurologic injury. The use of hyperosmolar fluids, such as hypertonic saline, has gained significant interest because they are devoid of dehydrating properties and may have other beneficial properties for patients with TBI. Electrolyte derangements are also common after neurologic injury, with many having neurologic manifestations. In addition, the role of electrolyte abnormalities in the secondary neurologic injury cascade is being delineated and may offer a potential future therapeutic intervention.

Variables during Care of Adult Donors That Can Influence Outcomes of Kidney Transplantation

Publications that relate characteristics of donors to renal function of recipients are reviewed. Most publications report retrospective observations that relate outcomes to donor variables that cannot be altered during donor care. Factors that can be altered in adult donors in an effort to improve recipients' outcomes include urine output and creatinine level. Increasing urine output to more than 100 mL/h, at least during the hour before explantation, and returning the creatinine level to match its serum concentration when the patient was admitted can improve outcomes. Ways of accomplishing those goals during donor care are discussed, with emphasis on support of renal blood flow.

Controversies in the use of hydroxyethyl starch solutions in small animal emergency and critical care

OBJECTIVES

To (1) review the development and medical applications of hydroxyethyl starch (HES) solutions with particular emphasis on its physiochemical properties; (2) critically appraise the available evidence in human and veterinary medicine, and (3) evaluate the potential risks and benefits associated with their use in critically ill small animals.

DATA SOURCES

Human and veterinary original research articles, scientific reviews, and textbook sources from 1950 to the present.

HUMAN DATA SYNTHESIS

HES solutions have been used extensively in people for over 30 years and ever since its introduction there has been a great deal of debate over its safety and efficacy. Recently, results of seminal trials and meta-analyses showing increased risks related to kidney dysfunction and mortality in septic and critically ill patients, have led to the restriction of HES use in these patient populations by European regulatory authorities. Although the initial ban on the use of HES in Europe has been eased, proof regarding the benefits and safety profile of HES in trauma and surgical patient populations has been requested by these same European regulatory authorities.

VETERINARY DATA SYNTHESIS

The veterinary literature is limited mostly to experimental studies and clinical investigations with small populations of patients with short-term end points and there is insufficient evidence to generate recommendations.

CONCLUSIONS

Currently, there are no consensus recommendations regarding the use of HES in veterinary medicine. Veterinarians and institutions affected by the HES restrictions have had to critically reassess the risks and benefits related to HES usage based on the available information and sometimes adapt their procedures and policies based on their reassessment. Meanwhile, large, prospective, randomized veterinary studies evaluating HES use are needed to achieve relevant levels of evidence to enable formulation of specific veterinary guidelines.

Effect of synthetic colloid administration on coagulation in healthy dogs and dogs with systemic inflammation

Background

Synthetic colloids are often used during fluid resuscitation and affect coagulation.

Objective

To compare the effects of an isotonic crystalloid and synthetic colloid on coagulation in healthy dogs and dogs with systemic inflammation.

Animals

Sixteen adult purpose‐bred Beagles.

Methods

Randomized, placebo‐controlled, blinded study. Dogs were randomized into one of two groups receiving fluid resuscitation with either 40 mL/kg IV 0.9% NaCl or tetrastarch after administration of lipopolysaccharide or an equal volume of placebo. After a 14‐day washout period, the study was repeated such that dogs received the opposite treatment (LPS or placebo) but the same resuscitation fluid. Blood samples were collected at 0, 1, 2, 4, and 24 hours for measurement of coagulation variables.

Results

Administration of either fluid to healthy dogs and dogs with systemic inflammation resulted in similar increases in prothrombin time and activated clotting time. In comparison to saline administration, tetrastarch administration resulted in significantly decreased R (P = .017) in healthy dogs, as well as significantly increased activated partial thromboplastin time (P ≤ .016), CL30% (P ≤ .016), and K (P < .001) and significantly decreased platelet count (P = .019), α (P ≤ .001), MA (P < .001), and von Willebrand factor antigen (P < .001) and collagen binding activity (P ≤ .003) in both healthy dogs and dogs with systemic inflammation.

Conclusions and Clinical Importance

Tetrastarch bolus administration to dogs with systemic inflammation resulted in a transient hypocoagulability characterized by a prolonged activated partial thromboplastin time, decreased clot formation speed and clot strength, and acquired type 1 von Willebrand disease.

Epidurals in patients receiving thromboprophylaxis with unfractionated heparin three times a day: the value of activated partial thromboplastin time testing

BACKGROUND

Dosing subcutaneous (SC) unfractionated heparin (UFH) 3 times a day (TID) for deep venous thrombosis prophylaxis is used for patients in the United States undergoing nonorthopedic surgery. There is a lack of data on the risks of neuraxial techniques in patients receiving TID SC UFH; however, concerns have been raised about higher bleeding risks. In this prospective study, we evaluated the value of activated partial thromboplastin time (aPTT) testing at the time of removal of epidural catheters as a risk-reduction strategy for this population.

METHODS

We collected data from our electronic hospital databases for all patients receiving epidural analgesia in conjunction with 5000 units TID or twice daily dosing (BID) SC UFH from December 2011 to December 2013. Our cohort received aPTT testing before removal of the catheter in all patients receiving TID SC UFH. An aPTT was ordered for patients receiving BID SC UFH only if risk factors for abnormal coagulation variables were identified. Chart reviews were performed on all patients with abnormal aPTT values to evaluate contributing risk factors.

RESULTS

Over a 2-year period, 3523 epidurals were placed at our institution, including 714 (20.3%) for patients receiving TID SC UFH, and 1594 (45.2%) for patients receiving BID SC UFH. Of those patients receiving BID SC UFH, 186 (11.7%) had aPTT values drawn on the basis of risk factors. Ten (5.4 %, 95% CI: 2.6%-9.7%) of those patients had an aPTT value of greater than 35 seconds on the date of epidural removal. Of those patients receiving TID SC UFH, 20 (2.8%, 95% CI: 1.7%-4.3%) had an initial aPTT value of more than 35 seconds on the date of epidural removal. All patients who had abnormal aPTT values on TID heparin dosing were identified as having obvious concomitant risk factors for coagulation parameter abnormalities. There were no epidural hematomas in patients receiving either BID or TID dosing (95% CI: 0%-0.001%).

CONCLUSIONS

The routine use of aPTT testing on patients receiving TID SC UFH at the time of removal of epidural catheters as a risk-reduction strategy is not supported by our results, where only 2.8% (95% CI: 1.7%-4.3%) of these patients had abnormal aPTT values. Our study adds to the limited data currently available on the safety of epidural analgesia in patients receiving TID SC UFH. Given the rare incidence of neuraxial hematoma (95% CI: 0%-0.001%), definitive conclusions on the risks of TID SC UFH administration in patients receiving epidural analgesia cannot be drawn based on our sample size.

Comparison of the in vitro effects of saline, hypertonic hydroxyethyl starch, hypertonic saline, and two forms of hydroxyethyl starch on whole blood coagulation and platelet function in dogs

OBJECTIVE

To compare the in vitro effects of hypertonic solutions and colloids to saline on coagulation in dogs.

DESIGN

In vitro experimental study.

SETTING

Veterinary teaching hospital.

ANIMALS

Twenty-one adult dogs.

INTERVENTIONS

Blood samples were diluted with saline, 7.2% hypertonic saline solution with 6% hydroxyethylstarch with an average molecular weight of 200 kDa and a molar substitution of 0.4 (HH), 7.2% hypertonic saline (HTS), hydroxyethyl starch (HES) 130/0.4 or hydroxyethyl starch 600/0.75 at ratios of 1:22 and 1:9, and with saline and HES at a ratio of 1:3.

MEASUREMENTS AND MAIN RESULTS

Whole blood coagulation was analyzed using rotational thromboelastometry (extrinsic thromboelastometry-cloting time (ExTEM-CT), maximal clot firmness (MCF) and clot formation time (CFT) and fibrinogen function TEM-CT (FibTEM-CT) and MCF) and platelet function was analyzed using a platelet function analyzer (closure time, CTPFA ). All parameters measured were impaired by saline dilution. The CTPFA was prolonged by 7.2% hypertonic saline solution with 6% hydroxyethylstarch with an average molecular weight of 200 kDa and a molar substitution of 0.4 (HH) and HTS but not by HES solutions. At clinical dilutions equivalent to those generally administered for shock (saline 1:3, HES 1:9, and hypertonic solutions 1:22), CTPFA was more prolonged by HH and HTS than other solutions but more by saline than HES. No difference was found between the HES solutions or the hypertonic solutions. ExTEM-CFT and MCF were impaired by HH and HTS but only mildly by HES solutions. At clinically relevant dilutions, no difference was found in ExTEM-CFT between HTS and saline or in ExTEM-MCF between HH and saline. No consistent difference was found between the 2 HES solutions but HH impaired ExTEM-CFT and MCF more than HTS. At high dilutions, FibTEM-CT and -MCF and ExTEM-CT were impaired by HES.

CONCLUSIONS

Hypertonic solutions affect platelet function and whole blood coagulation to a greater extent than saline and HES. At clinically relevant dilutions, only CTPFA was markedly more affected by hypertonic solutions than by saline. At high dilutions, HES significantly affects coagulation but to no greater extent than saline at clinically relevant dilutions.

Effects of hemoglobin-based oxygen carriers on blood coagulation

For many decades, Hemoglobin-based oxygen carriers (HBOCs) have been central in the development of resuscitation agents that might provide oxygen delivery in addition to simple volume expansion. Since 80% of the world population lives in areas where fresh blood products are not available, the application of these new solutions may prove to be highly beneficial (Kim and Greenburg 2006). Many improvements have been made to earlier generation HBOCs, but various concerns still remain, including coagulopathy, nitric oxide scavenging, platelet interference and decreased calcium concentration secondary to volume expansion (Jahr et al. 2013). This review will summarize the current challenges faced in developing HBOCs that may be used clinically, in order to guide future research efforts in the field.

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.

In vitro effect of hydroxyethyl starch 130/0.42 on canine platelet function

OBJECTIVE

To evaluate the effect of 6% hydroxyethyl starch (HES) solution, with a molecular weight of 130 kDa and a degree of substitution of 0.42, on canine platelet function in vitro.

SAMPLES

Blood samples from 31 healthy adult dogs.

PROCEDURES

Citrated blood was diluted with saline (0.9% NaCl) solution or HES 130/0.42 in ratios of 1:9 (ie, 1 part saline solution or HES 130/0.42 and 9 parts blood) and 1:3. Platelet plug formation time (closure time [Ct]) was measured with a platelet function analyzer and cartridges coated with collagen and ADP.

RESULTS

Median baseline Ct with citrated blood was 84.0 seconds (interquartile range, 74.5 to 99.5 seconds). Results obtained with 1:9 dilutions with saline solution and HES 130/0.42 were not significantly different from baseline results. The 1:3 dilutions with saline solution and HES 130/0.42 resulted in median Cts of 96.0 seconds (interquartile range, 85.5 to 110.8 seconds) and 112.0 seconds (92.0 to 126.0 seconds), respectively. Results obtained with both 1:3 dilutions were significantly different from baseline results. The Ct obtained with the HES dilution was also significantly different from that of the 1:3 dilution with saline solution.

CONCLUSIONS AND CLINICAL RELEVANCE

Saline solution and HES 130/0.42 in a 1:3 dilution affected canine platelet function by prolonging Cts. The HES 130/0.42 had a significantly greater effect on canine platelets than did saline solution.

Massive transfusion: an overview of the main characteristics and potential risks associated with substances used for correction of a coagulopathy

Massive transfusion (MT) is an empiric mode of treatment advocated for uncontrolled bleeding and massive haemorrhage, aiming at optimal resuscitation and aggressive correction of coagulopathy. Conventional guidelines recommend early administration of crystalloids and colloids in conjunction with red cells, where the red cell also plays a critical haemostatic function. Plasma and platelets are only used in patients with microvascular bleeding with PT/APTT values >1.5 times the normal values and if PLT counts are below 50×10(9)/L. Massive transfusion carries a significant mortality rate (40%), which increases with the number of volume expanders and blood components transfused. Controversies still exist over the optimal ratio of blood components with respect to overall clinical outcomes and collateral damage. While inadequate transfusion is believed to be associated with poor outcomes but empirical over transfusion results in unnecessary donor exposure with an increased rate of sepsis, transfusion overload and infusion of variable amounts of some biological response modifiers (BRMs), which have the potential to cause additional harm. Alternative strategies, such as early use of tranexamic acid are helpful. However in trauma settings the use of warm fresh whole blood (WFWB) instead of reconstituted components with a different ratio of stored components might be the most cost effective and safer option to improve the patient's survival rate and minimise collateral damage. This manuscript, after a brief summary of standard medical intervention in massive transfusion focuses on the main characteristics of various substances currently available to overcome massive transfusion coagulopathy. The relative levels of some BRMs in fresh and aged blood components of the same origin are highlighted and some myths and unresolved issues related to massive transfusion practice are discussed. In brief, the coagulopathy in MT is a complex phenomenon, often complicated by chronic activation of coagulation, platelets, complement and vascular endothelial cells, where haemolysis, microvesiculation, exposure of phosphatidyl serine positive cells, altered red cells with reduced adhesive proteins and the presence of some BRM, could play a pivotal role in the coagulopathy and untoward effects. The challenges of improving the safety of massive transfusion remain as numerous and as varied as ever. The answer may reside in appropriate studies on designer whole blood, combined with new innovative tools to diagnosis a coagulopathy and an evidence based mode of therapy to establish the optimal survival benefit of patients, always taking into account the concept of harm reduction and reduction of collateral damage.

Adverse events and safety issues in blood donation--a comprehensive review

Although blood donation is generally safe, a variety of risks and complications exist, the most common being iron deficiency, vasovagal reactions and citrate-related events. In the last decades, extensive efforts have significantly improved recipient and product safety, but there is still great potential to optimise donor care. Many therapies in modern medicine depend on the prompt availability of blood products, therefore it is crucial to maintain a motivated and healthy donor pool in view of a limited number of healthy volunteers willing and able to give blood or blood components. We present a comprehensive review on adverse events addressing all types of blood donation including whole blood, plasma, platelet, peripheral blood stem cell, leucocyte and bone marrow donation. In addition, we outline strategies for the prevention and treatment of these events and give a blueprint for future research in this field.

One pathway to academic success: autobiography of Dr Ronald G. Strauss

Often, I have been asked by "junior faculty"-who are usually burdened by substantial responsibilities in service and teaching-how they can launch their career in research as a means to succeed in academic medicine. Obviously, the answers/solutions are as diverse as are the circumstances of each questioner. In the following article, I offer the approach that I applied to my career-acknowledging that "one shoe doesn't fit all" and that others will advise differently. However, one truism exists whenever one seeks excellence in anything-the opportunity must be present to commit uninterrupted time for thought/concentration, organization, training/mentoring/study, and effort/hard work. Without such an opportunity, success in research will be elusive.

[The "Seville" Consensus Document on Alternatives to Allogenic Blood Transfusion. Sociedades españolas de Anestesiología (SEDAR), Medicina Intensiva (SEMICYUC), Hematología y Hemoterapia (AEHH), Transfusión sanguínea (SETS) Trombosis y Hemostasia (SETH)]

The Consensus Document on Alternatives to Allogenic Blood Transfusion (AABT) has been drawn up by a panel of experts from 5 scientific societies. The Spanish Societies of Anesthesiology (SEDAR), Critical Care Medicine and Coronary Units (SEMICYUC), Hematology and Hemotherapy (AEHH), Blood Transfusion (SETS) and Thrombosis and Hemostasis (SETH) have sponsored and participated in this Consensus Document. Alternatives to blood transfusion have been divided into pharmacological and non-pharmacological, with 4 modules and 12 topics. The main objective variable was the reduction of allogenic blood transfusions and/or the number of transfused patients. The extent to which this objective was achieved by each AABT was evaluated using the Delphi method, which classifies the grade of recommendation from A (supported by controlled studies) to E (non-controlled studies and expert opinion). The experts concluded that most of the indications for AABT were based on middle or low grades of recommendation, "C", "D", or "E", thus indicating the need for further controlled studies.

Influence of colloid infusion on coagulation during off-pump coronary artery bypass grafting

This study was conducted to determine the influence of colloid infusion on coagulation in patients undergoing off-pump coronary artery bypass grafting (OP-CABG). Thirty patients undergoing elective OP-CABG received medium molecular weight hydroxyethyl starch group I (MMW-HES 200/0.5), low molecular weight hydroxyethyl starch group II (LMW-HES 130/0.4) or gelatin group III (GEL) in a prospective randomized trial. Blood samples were assessed for hemoglobin (Hb), activated coagulation time (ACT), prothrombin time (PT), activated partial thromboplastin time (aPPT), platelet count, fibrinogen and von Willebrand factor (vWF) at specified intervals. Total volume of the colloid infused and postoperative chest-time drainage was also measured. There was a significant decrease in Hb, platelet count, fibrinogen levels in all these groups, which did not warrant blood transfusion. After the colloid infusion, vWF decreased significantly to 67% from baseline in group I as compared to 85 and 79% in group II and group III, respectively. vWF levels remained lower than the baseline value in the first 24 hours in group I, whereas this factor level increased above the baseline values in groups II and III, 6 hours postoperatively. Postoperative chest tube drainage in 24 hours was significantly higher in group I (856 ± 131 ml) as compared to group II (550 ± 124 ml) and group III (582 ± 159 ml). LMW-HES 130/0.4 was superior to MMW-HES 200/0.5 and gelatin in patients undergoing OP-CABG, in terms of better preservation of coagulation associated with enhanced volume effect.

Effects of 6% hetastarch (600/0.75) or lactated Ringer's solution on hemostatic variables and clinical bleeding in healthy dogs anesthetized for orthopedic surgery

OBJECTIVE

To evaluate and compare hemostatic variables and clinical bleeding following the administration of 6% hetastarch (600/0.75) or lactated Ringer's solution (LRS) to dogs anesthetized for orthopedic surgery.

STUDY DESIGN

Randomized blinded prospective study.

ANIMALS

Fourteen, healthy adult mixed-breed hound dogs of either sex, aged 11-13 months, and weighing 20.8±1.2 kg.

METHODS

The dogs were randomly assigned to receive a 10 mL kg(-1) intravenous (i.v.) bolus of either 6% hetastarch (600/0.75) or LRS over 20 minutes followed by a maintenance infusion of LRS (10 mL kg(-1)  hour(-1)) during anesthesia. Before (Baseline) and at 1 and 24 hours after bolus administration, packed cell volume (PCV), total protein concentration (TP), prothrombin time (PT), activated partial thromboplastin time (APTT), von Willebrand's factor antigen concentration (vWF:Ag), factor VIII coagulant activity (F VIII:C), platelet count, platelet aggregation, colloid osmotic pressure (COP) and buccal mucosal bleeding time (BMBT) were measured. In addition a surgeon who was blinded to the treatments assessed bleeding from the incision site during the procedure and at 1 and 24 hours after the bolus administration.

RESULTS

Following hetastarch or LRS administration, the PCV and TP decreased significantly 1-hour post-infusion. APTT did not change significantly compared to baseline in either treatment group, but the PT was significantly longer at 1-hour post-infusion than at 24 hours in both groups. No significant change was detected for vWF:Ag, FVIII:C, platelet aggregation or clinical bleeding in either group. The BMBT increased while platelet count decreased significantly at 1-hour post-infusion in both groups. The COP decreased significantly in both treatment groups 1-hour post-infusion but was significantly higher 1-hour post-infusion in the hetastarch group compared to the LRS group.

CONCLUSIONS AND CLINICAL RELEVANCE

At the doses administered, both hetastarch and LRS can alter hemostatic variables in healthy dogs. However, in these dogs undergoing orthopedic surgery, neither fluid was associated with increased clinical bleeding.

Pre-clinical studies using OxyVita hemoglobin, a zero-linked polymeric hemoglobin: a review

Hemoglobin-based oxygen carriers (HBOC) are being developed to provide the oxygen necessary in clinical situations when whole blood is not available. The safety and effectiveness of each HBOC must be determined before clinical approval. In the past several years animal studies have been conducted with zero-linked polymers to evaluate their effectiveness at delivering oxygen in vivo. Studies have addressed issues associated with interstitial extravasation, cerebral ischemia and blood flow, resuscitation, and coagulation interactions. Several of the investigations reviewed are based on early preparations of zero-linked polymerized bovine hemoglobins (ZL-HbBv), which contained a wide range of high-molecular-weight polymers. Recent studies using the Oxyvita product OxyVita Hb, which contains a more homogenous population (97%) of large-molecular-weight species (~17 MDa), are also included in this review.

Fluids after cardiac surgery: a pilot study of the use of colloids versus crystalloids

OBJECTIVES

To determine whether a starch solution for volume resuscitation in a flow-based protocol improves circulatory status better than a crystalloid solution, as defined by the need for catecholamines in patients the morning after cardiac surgery, and whether this can be performed without increased morbidity.

DESIGN

Concealed, randomized, double-blind, controlled trial.

PARTICIPANTS

Two hundred sixty-two patients who underwent cardiac surgery at a tertiary care hospital.

INTERVENTIONS

Based on predefined criteria indicating a need for fluids, and a nurse-delivered algorithm that used central venous pressure and cardiac index obtained from a pulmonary artery catheter, patients were allocated to receive 250-mL boluses of 0.9% saline or a 250-molecular weight 10% solution of pentastarch.

RESULTS

Two hundred thirty-seven patients received volume boluses: 119 hydroxyethyl starches and 118 saline. Between 8:00 am and 9:00 am the morning after surgery, 13 (10.9%) of hydroxyethyl starch patients and 34 (28.8%) saline patients were using catecholamines (p = .001). Hydroxyethyl starch patients had less pneumonia and mediastinal infections (p = .03) and less cardiac pacing (p = .03). There were two deaths in each group. There was no difference in the daily creatinine, development of RIFLE risk criteria during hospital stay, or new dialysis. The numbers and volumes of packed red blood cells were similar in the two groups, but more hydroxyethyl starch patients received plasma transfusions (p = .05).

CONCLUSIONS

Use of a colloid solution for volume resuscitation in a nurse-delivered flow-based algorithm, which included a pulmonary artery catheter, significantly improved hemodynamic status, an important factor for readiness for discharge from the intensive care unit.

5% dimethyl sulfoxide (DMSO) and pentastarch improves cryopreservation of cord blood cells over 10% DMSO

BACKGROUND

Cell number and viability are important in cord blood (CB) transplantation. While 10% dimethyl sulfoxide (DMSO) is the standard medium, adding a starch to freezing medium is increasingly utilized as a cytoprotectant for the thawing process. Similar to hetastarch, pentastarch has the advantages of faster renal clearance and less effect on the coagulation system.

STUDY DESIGN AND METHODS

We compared a lower DMSO concentration (5%) containing pentastarch with 10% DMSO and performed cell viability assay, colony-forming units (CFUs), and transplantation of CB cells in NOD/SCID IL2Rγ(null) mice.

RESULTS

CB cells in 5% DMSO/pentastarch had similar CD34+, CD3+, and CD19+ cell percentages after thawing as fresh CB cells. CB cells in 5% DMSO/pentastarch had higher viability (83.3±9.23%) than those frozen in 10% DMSO (75.3±11.0%, p<0.05). We monitored cell viability postthaw every 30 minutes. The mean loss in the first 30 minutes was less in the 5% DMSO/pentastarch group. At the end of 3 hours, the viability decreased by a mean of 7.75% for the 5% DMSO/pentastarch and 17.5% for the 10% DMSO groups. CFUs were similar between the two cryopreserved groups. Frozen CB cells engrafted equally well in IL2Rγ(null) mice compared to fresh CB cells up to 24 weeks, and CB cells frozen in 5% DMSO/pentastarch engrafted better than those in 10% DMSO.

CONCLUSION

Our data indicate that the lower DMSO concentration with pentastarch represents an improvement in the CB cryopreservation process and could have wider clinical application as an alternate freezing medium over 10% DMSO.

Balanced hydroxyethylstarch preparations: are they all the same? In-vitro thrombelastometry and whole blood aggregometry

BACKGROUND AND OBJECTIVE

Haemostasis appears to be less altered with balanced than with unbalanced hydroxyethylstarch (HES) preparations. In a blinded in-vitro coagulation study, the effects of two HESs dissolved in different balanced solutions were measured.

METHODS

Blood from 12 healthy young male volunteers was diluted by 10, 30 and 50% by using either a balanced 6% HES 130/0.42 or a balanced 6% HES 130/0.4. Composition of the solvent of the two HES preparations differed. An unbalanced gelatin solution was used as a control. Rotation thrombelastometry was used to assess changes in coagulation, and whole blood aggregometry using three different inductors was used to assess the effects of dilution on platelet function.

RESULTS

Dilutions of 10 and 30% showed no significant changes in thrombelastometry data and platelet aggregation in all three groups. Fifty per cent haemodilution was associated with significantly more pronounced deterioration in clotting time, clot formation time and clot firmness, with the balanced HES 130/0.42 containing calcium than with the balanced HES without calcium. Platelet function was also more impaired by HES not containing calcium than by HES containing calcium. Extreme dilution with gelatin showed similar results to those of balanced HES 130/0.4.

CONCLUSION

Our in-vitro studies showed that extreme haemodilution with HES 130/0.42 dissolved in a balanced solution containing calcium was associated with less negative effects on thrombelastometry and platelet aggregation than HES 130/0.4 prepared in a balanced solution without calcium. Gelatin prepared in a nonbalanced solution showed similar effects on coagulation to balanced HES without calcium.

HES 130/0.4 impairs haemostasis and stimulates pro-inflammatory blood platelet function

Introduction

Hydroxyethyl starch (HES) solutions are widely used for volume replacement therapy but are also known to compromise coagulation, impair renal function and increase long-term mortality. To test the hypotheses that HES 130/0.4 has fewer adverse effects than HES 200/0.5 and exerts anti-inflammatory properties, we compared the effects of HES 130/0.4, HES 200/0.5 and saline on in vitro haemostasis and pro-inflammatory platelet function.

Methods

Whole blood samples from healthy volunteers were mixed with 6% HES 130/0.4, 10% HES 200/0.5, or normal saline to achieve a final haemodilution rate of 10% or 40%. Haemostatic capacity was characterised by thromboelastography (ROTEM) and measurement for FXIIIa activity. Platelet activation and pro-inflammatory platelet functions were characterised by flow cytometry measuring the platelet activation marker CD62P and binding of fibrinogen to platelets as well as the formation of heterotypic platelet-leukocyte conjugates.

Results

Compared with saline, HES 130/0.4 dose-dependently impaired formation and firmness of the fibrin clot but did not affect the fibrin crosslinking activity of FXIIIa. At 40% but not at 10% haemodilution rate, HES 200/0.5 also increased platelet fibrinogen binding and both HES solutions increased expression of CD62P, the main receptor for platelet-leukocyte adhesion. HES 130/0.4 but not HES 200/0.5 increased formation of platelet-neutrophil conjugates and, to a lesser degree, platelet-monocyte conjugates.

Conclusions

Our data demonstrate that HES 130/0.4 has similar adverse effects as HES 200/0.5. In particular, both types of HES impair coagulation capacity and stimulate, rather than attenuate, pro-inflammatory platelet function.

Photo-Optical Methods Can Lead to Clinically Relevant Overestimation of Fibrinogen Concentration in Plasma Diluted With Hydroxyethyl Starch

Background: Adequate fibrinogen concentration is a crucial component of sufficient perioperative/posttraumatic hemostasis. In major blood loss, large volumes of fluids are being administered, which have been shown to interfere with valid determination of fibrinogen concentration. This may lead to wrong treatment decisions. We studied the variables that cause the discrepancies between measured and true fibrinogen concentrations in samples diluted with volume replacement fluids. Methods: Citrated plasma samples of healthy volunteers were diluted by 30% and 50% with phosphate buffered saline (PBS), hydroxyethyl starch (HES) 10% (200/0.5), or gelatine (GEL). Fibrinogen concentrations of diluted samples were derived from the prothrombin time (PT) and the Clauss method (CLS) was applied. With the latter, several modifications and combinations of detection principles and thrombin reagents were investigated. Values were compared with ‘‘true,’’ that is, calculated values based on the results of undiluted samples for each method. Results: Photo-optical methods resulted in significant overestimation of the fibrinogen concentration in blood diluted with HES, depending on the thrombin reagent used. This was particularly true for modifications of the CLS aimed at measuring low fibrinogen concentrations. Use of another thrombin reagent gave satisfactory results for this modification. The validity of mechanical end point determination methods was considered sufficient and was not influenced by the use of different thrombin reagents. Conclusions: Fibrinogen determination methods used in situations of major blood loss need to be validated with samples containing significant amounts of volume replacement fluids, particularly colloids. Only some combinations of test principle, detection method, and reagents will give valid results.

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

Haemostatic alterations associated with the use of fluids are related to non-specific dilutional effects and colloid-specific effects, such as acquired von Willebrand syndrome, inhibition of platelet function and fibrin polymerization. Judging by currently available evidence, dextran, hetastarch and pentastarch have a more pronounced impact than tetrastarch, gelatin and albumin. In patients with hypocoagulability, tetrastarch appears to be a suitable volume expander due to its high safety index and volume efficacy. Gelatins have lower inhibitory effects on clot strength compared with tetrastarch, but their volume efficacy is also lower. Dextrans are potent anticoagulants with a high risk for adverse reactions. Albumin has negligible effects on haemostasis, but low volume efficacy and costs limit the use of a blood product as a routine volume replacement fluid. To avoid potential acidosis-induced changes in haemostasis, plasma-adapted carrier solutions may be used instead of saline-based solutions.

Does Hextend impair coagulation compared to 6% hetastarch? An ex vivo thromboelastography study

The objective of this study was to determine if coagulation is different between 6% hetastarch in normal saline (NS) and 6% hetastarch in lactated Ringer's solution (LR), with use of an ex vivo thromboelastography (TEG) model with healthy donated volunteer blood. We simulated hemodilution that occurs during clinical resuscitation of hemorrhagic or hypovolemic shock, using healthy human donor whole blood (WB) ex vivo. Coagulopathy related to low, medium, high, or very high dilution of WB with NS or a high-molecular-weight hetastarch-based plasma expander, 6% hetastarch in NS (HSNS) or 6% hetastarch in lactated Ringer's [Hextend (HSLR)], was analyzed by thromboelastography (TEG). No changes were noted in the TEG profile of undiluted WB controls during the 6-hour period of use (P > 0.95). Dilution with HSNS and HSLR significantly impaired coagulation compared to both WB control and NS. Progressive dilution with NS impaired coagulation but to a lesser extent than colloids (P < 0.01). Low dilution of blood with NS increased clot strength by 12% (not significant; P = 0.097). We conclude that WB containing citrate obtained from healthy donors for TEG analysis yields reproducible data over a minimum of 6 hours. Either hetastarch, when present at concentrations comparable to the manufacturer's maximum recommended dose of 20 mL/kg (equivalent to the high dilution used in these experiments), decreases clot tensile strength to levels associated with an increased risk of bleeding. Substitution of lactated Ringer's for NS in 6% hetastarch appears to offer no advantage in avoiding hemostatic compromise in an in vitro model.

Effect of haemodilution, acidosis, and hypothermia on the activity of recombinant factor VIIa (NovoSeven)

Background

A range of plasma volume expanders is used clinically, often in settings where haemostasis may already be impaired. The haemostatic agent, recombinant activated factor VII (rFVIIa, NovoSeven^®), may be used to improve haemostasis but potential interactions with different volume expanders are poorly understood.

Methods

Clot formation was measured by thromboelastography (TEG) using blood from healthy volunteers. In vitro effects of rFVIIa with haemodilution, acidosis, and hypothermia were examined. Conditions were induced by dilution with NaCl (0.9%), lactated Ringer's solution, albumin 5%, or hydroxyethyl starch (HES) solutions [MW (molecular weight) 130–670 kDa]; by adjusting pH to 6.8 with 1 M HEPES (N-2-hydroxyethylpiperazine-N′-2-ethanesulphonic acid) buffer; or by reducing temperature to 32°C. We also studied the effect of low vs high MW HES (MW 200 vs 600 kDa) and rFVIIa on in vivo bleeding time (BT) in rabbits.

Results

Haemodilution progressively altered TEG parameters. rFVIIa improved TEG parameters in the presence of acidosis, hypothermia or 20% haemodilution (P<0.05). At 40% haemodilution, the rFVIIa effect was diminished particularly with high MW HES. In vivo, rFVIIa shortened the BT (P<0.05) with low but not high MW HES.

Conclusions

Efficacy of rFVIIa was affected by the degree of haemodilution and type of volume expander, but not by acidosis or hypothermia.

[Coagulopaty in associated with massive transfusion]

Massive hemorrhage is a formidable challenge for anesthesia care providers in the elective setting and poses even greater potential challenges in the trauma setting. In all this cases, the anesthesia care providers are faced with large-volume resuscitations that typically start with crystalloid and colloid and rapidly progress to blood and blood products. These large-volume replacement may cause coagulopathy, which can be difficult to manage in the setting of ongoing blood loss. Coagulopathy associated with massive transfusion is multifactorial event that results from hemodilution, hypothermia, the use of fractionated blood products and disseminated intravascular coagulation. Maintaining a normal body temperature is a first-line, effective strategy to improve hemostasis during massive transfusion. Treatment strategies include the maintenance of adequate tissue perfusion, the corection of anemia, and the use of hemostatic blood products.

A new plasma-adapted hydroxyethylstarch preparation: in vitro coagulation studies using thrombelastography and whole blood aggregometry

BACKGROUND

The lack of acceptance of hydroxyethylstarch (HES) for intravascular volume replacement is most likely due to reports of abnormal coagulation. In a blinded in vitro study, we compared the effects on hemostasis of a new HES, prepared in a balanced solution, with a conventional HES preparation and Ringer's lactate solution.

METHODS

Blood was taken from 10 healthy young male volunteers. Blood was diluted by 10%, 30%, and 50% using either 6% HES 130/0.42 prepared in a balanced solution, a conventional nonbalanced 6% HES 130/0.4 or Ringer's lactate solution. Rotation thrombelastography, was performed after adding two activators (thromboplastin-phospholipid to monitor the intrinsic system; tissue factor to monitor the extrinsic system). Whole blood aggregometry adding adenosine diphosphate, collagen, and thrombin receptor-activating protein was used to assess changes of platelet function.

RESULTS

Dilution of blood (30% and 50%) resulted in clot formation time that was significantly more prolonged in the nonbalanced than in the balanced HES group. In the 50% diluted sample using the unbalanced HES, maximum clot firmness was significantly more reduced than by 50% dilution using the balanced HES. In the 50% diluent using the nonbalanced HES, adenosine diphosphate-, collagen-, and thrombin receptor activating protein-induced aggregometry was more reduced than in the balanced HES group.

CONCLUSIONS

A balanced HES preparation showed fewer negative effects on thrombelastographic data and platelet aggregation than a nonbalanced HES preparation, especially when using higher degrees of dilution. Future clinical studies may show a decreased influence of balanced HES solutions on coagulation.

The effect of colloid and crystalloid preloading on thromboelastography prior to Cesarean delivery

PURPOSE

Fluid preloading with colloids reduces hypotension after spinal anesthesia for Cesarean delivery more effectively than crystalloids. However, the effects of fluid preloading regimens on coagulation in pregnant patients remain unresolved. The aim of this study was to compare the effects on coagulation of fluid preloading with 6% hydroxyethyl starch (HES) and lactated Ringer's (LR) solution using thromboelastography (TEG) with kaolin-activated whole blood in healthy pregnant patients prior to spinal anesthesia for Cesarean delivery.

METHODS

After obtaining Ethics committee approval, 30 parturients were prospectively randomized prior to spinal anesthesia for elective Cesarean delivery to receive fluid preloading with either 1500 mL LR or 500 mL 6% HES over 30 min. Thromboelastography was performed immediately prior to and after fluid preloading. Standard TEG parameters were analyzed in terms of r time (min), k time (min), alpha angle (degrees) and maximum amplitude (mm).

RESULTS

Group HES had statistically significant longer reaction times (r) and clot formation times (k) after fluid loading compared to baseline values (P < 0.05 respectively), although these post-fluid loading TEG parameters remained within a normal reference range. No significant differences in TEG values were seen after preloading within the LR group.

CONCLUSION

Fluid preloading with 500 mL 6% HES in healthy parturients produced mild coagulation effects, as measured with TEG, prior to spinal anesthesia for Cesarean delivery. No significant effects on coagulation with TEG were observed following preloading with 1500 mL LR.

Tranexamic acid does not correct the haemostatic impairment caused by hydroxyethyl starch (200 kDa/0.5) after cardiac surgery

We investigated the effect of intravenous tranexamic acid on hydroxyethyl starch (HES)-induced clot strength impairment after cardiac surgery. Patients were randomized to receive either 1 g tranexamic acid or the same volume of 0.9% saline after administration of 15 ml/kg of 6% HES (molecular weight, 200 kDa; degree of substitution, 0.5) in the immediate postoperative period. Modified thromboelastometry (ROTEM) using different activators [intrinsic ROTEM (InTEM), extrinsic ROTEM (ExTEM), fibrinogen ROTEM (FibTEM)] was carried out to evaluate clot formation and lysis. The clot formation time was prolonged, and the maximum clot firmness (MCF) and shear elastic modulus [G = 5000 x MCF / (100-MCF), dynes/cm(2)] decreased (all activators of ROTEM) after completion of HES (P < 0.001, two-factor analysis of variance). These abnormalities in blood coagulation persisted despite tranexamic acid. Maximal lysis (FibTEM), indicative of fibrinolytic activity, was increased after HES but no effect of tranexamic acid was observed. The cumulative chest tube drainage until the first postoperative morning was not different between the groups (1008 +/- 251 and 1081 +/- 654 ml, P = 0.698, respectively). We conclude that after cardiopulmonary bypass, HES-induced impairment in clot formation and strength, or increased fibrinolytic capacity, is not reversed by the administration of tranexamic acid.

Perioperative fluid management in renal transplantation: a narrative review of the literature

Adequate volume maintenance is essential to prevent acute renal failure during major surgery or to ensure graft function after renal transplantation. The various recommendations on the optimum fluid therapy are based, at best, on sparse evidence only from observational studies. This article reviews the literature on perioperative fluid management in renal transplantation. Crystalloid solutions not exerting any specific side-effects are the first choice for volume replacement in kidney transplantation. The use of colloids should be restricted to patients with severe intravascular volume deficits necessitating high volume restoration. The routine application of albumin, dopamine, and high dose diuretics is no longer warranted. Mannitol given immediately before removal of the vessel clamps reduces the requirement of post-transplant dialysis, but has no effects on graft function in the long term. There is insufficient evidence on the best use of dialysis, but it seems peritoneal dialysis pretransplant is associated with less delayed graft function, whereas the preference of dialysis post-transplant is not yet well-founded. This review article should provide better guidance for fluid management in kidney transplantation until best-evidence guidelines can be established based upon more research.

Massive transfusion and coagulopathy: pathophysiology and implications for clinical management

PURPOSE

To review the pathophysiology of coagulopathy in massively transfused, adult and previously hemostatically competent patients in both elective surgical and trauma settings, and to recommend the most appropriate treatment strategies.

METHODS

Medline was searched for articles on "massive transfusion," "transfusion," "trauma," "surgery," "coagulopathy" and "hemostatic defects." A group of experts reviewed the findings.

PRINCIPAL FINDINGS

Coagulopathy will result from hemodilution, hypothermia, the use of fractionated blood products and disseminated intravascular coagulation. The clinical significance of the effects of hydroxyethyl starch solutions on hemostasis remains unclear. Maintaining a normal body temperature is a first-line, effective strategy to improve hemostasis during massive transfusion. Red cells play an important role in coagulation and hematocrits higher than 30% may be required to sustain hemostasis. In elective surgery patients, a decrease in fibrinogen concentration is observed initially while thrombocytopenia is a late occurrence. In trauma patients, tissue trauma, shock, tissue anoxia and hypothermia contribute to the development of disseminated intravascular coagulation and microvascular bleeding. The use of platelets and/or fresh frozen plasma should depend on clinical judgment as well as the results of coagulation testing and should be used mainly to treat a clinical coagulopathy.

CONCLUSIONS

Coagulopathy associated with massive transfusion remains an important clinical problem. It is an intricate, multifactorial and multicellular event. Treatment strategies include the maintenance of adequate tissue perfusion, the correction of hypothermia and anemia, and the use of hemostatic blood products to correct microvascular bleeding.

A randomised trial comparing 5 mL/kg and 10 mL/kg of pentastarch as a volume preload before spinal anaesthesia for elective caesarean section

BACKGROUND

Colloid solutions are more effective at preventing hypotension than crystalloids when used as a volume preload before caesarean delivery under spinal anaesthesia. The ideal volume to infuse has not been established.

METHOD

In a randomised double-blind trial 70 women presenting for elective caesarean section received either 5 mL/kg of pentastarch (group A) or 10 mL/kg of pentastarch (group B) as a volume preload before spinal anaesthesia. Hypotension was defined as a systolic pressure below 90 mmHg or a decrease of 30% from a baseline value. Treatment was with 6-mg increments of ephedrine until resolution.

RESULTS

In group B, 7/35 patients (20%) developed hypotension, significantly fewer than the 15/35 (42.8%) in group A (P<0.05). The patients in group B also required less ephedrine (total in group, 114 mg) than those in group A (total in group, 198 mg)

CONCLUSIONS

Pentastarch, 10 mL/kg is more effective than 5 mL/kg at preventing hypotension following spinal anaesthesia for caesarean delivery.