Postoperative blood loss and transfusion associated with use of Hextend in cardiac surgery patients at a blood conservation center

Effect of Hydroxyethyl Starch Priming on the Systemic Inflammatory Response and Lung Edema after Cardiopulmonary Bypass in a Rat Model

Cardiopulmonary bypass (CPB) preserves patients' lives during open heart surgery by providing sufficient oxygen delivery and blood supply to vital organs. However, previous studies have suggested that the interaction of hemodilution and vascular hyperpermeability induces tissue edema and an inflammatory response during CPB. In this study, we hypothesized the suppression of the systemic inflammatory response and tissue edema during CPB by a plasma substitute (hydroxyethyl starch [HES]). Rats (450-500 g) were divided into a SHAM group (n = 5), a Ringer's acetate CPB group (n = 7), and an HES CPB group (n = 7). In the Ringer's acetate group, the CPB circuit was primed with Ringer's acetate solution, and in the HES CPB group, it was primed with HES formulation (6% HES 130/0.4). Blood samples were collected before (baseline) and 30, 60, 90 and 120 min after initiation of CPB. Plasma cytokine levels of tumor necrosis factor-α, interleukin (IL)-6, and IL-10, and biochemical markers (lactate dehydrogenase, aspartate aminotransferase, alanine aminotransferase, blood urea nitrogen, creatinine, liver-type fatty acid-binding protein, and colloid osmotic pressure [COP]) were measured before and 30, 60, 90, and 120 min after the initiation of CPB. In the Ringer's acetate CPB group, the inflammatory cytokines and biochemical markers increased significantly during CPB compared with the SHAM group, but such increases were significantly suppressed in the HES CPB group. In addition, during CPB, it was possible to preserve normal plasma COP in the HES CPB group. The data suggest that 6% HES 130/0.4 is effective for suppressing the inflammatory response during CPB.

Coagulation complications following trauma

Traumatic injury is one of the leading causes of death, with uncontrolled hemorrhage from coagulation dysfunction as one of the main potentially preventable causes of the mortality. Hypothermia, acidosis, and resuscitative hemodilution have been considered as the significant contributors to coagulation manifestations following trauma, known as the lethal triad. Over the past decade, clinical observations showed that coagulopathy may be present as early as hospital admission in some severely injured trauma patients. The hemostatic dysfunction is associated with higher blood transfusion requirements, longer hospital stay, and higher mortality. The recognition of this early coagulopathy has initiated tremendous interest and effort in the trauma community to expand our understanding of the underlying pathophysiology and improve clinical treatments. This review discusses the current knowledge of coagulation complications following trauma.

In vitro evaluation of a novel system for monitoring surgical hemoglobin loss

BACKGROUND

Accurate measurement of intraoperative blood loss is an important clinical variable in managing fluid resuscitation and avoiding unnecessary transfusion of blood products. In this study, we measured surgical blood loss using a tablet computer programmed with a unique algorithm modeled after facial recognition technology. The aim of the study was to assess the accuracy and performance of the system on surgical laparotomy sponges in vitro.

METHODS

Whole blood samples of premeasured hemoglobin (Hb) and volume were reconstituted from units of human packed red blood cells and plasma and distributed across surgical laparotomy sponges. Normal saline was added to simulate the presence of varying levels of hemodilution and/or irrigation use. Soaked sponges from 4 different manufacturers were scanned using the Triton System with Feature Extraction Technology (Gauss Surgical, Inc., Palo Alto, CA) under 3 different ambient light conditions in an operating room. Accuracy of Hb loss measurement was evaluated relative to the premeasured values using linear regression and Bland-Altman analysis. Correlations between studied variables and measurement bias were analyzed using nonparametric tests.

RESULTS

The overall mean percent error for measure of Hb loss for the Triton System was 12.3% (95% confidence interval [CI], 8.2%-16.4%). A strong positive linear correlation between the premeasured and actual Hb masses was noted across the full range of intraoperative lighting conditions, including (A) high (r = 0.95 [95% CI, 0.93-0.96]), (B) medium (r = 0.94 [95% CI, 0.93-0.96]), and (C) low (r = 0.90 [95% CI, 0.87-0.93]) mean ambient light intensity. Bland-Altman analysis revealed a bias of 0.01 g [95% CI, -0.03 to 0.06 g] of Hb per sponge between the 2 measures. The corresponding lower and upper limits of agreement were -1.16 g (95% CI, -1.21 to -1.12 g) per sponge and 1.19 g (95% CI, 1.15-1.24 g) per sponge, respectively. Measurement bias of estimated blood loss and Hb mass using the new system were not associated with the volume of saline used to reconstitute the samples (P = 0.506 and P = 0.469, respectively), suggesting that the system is robust under a wide range of sponge saturation conditions.

CONCLUSIONS

Mobile blood loss monitoring using the Triton system is accurate in assessing Hb mass on surgical sponges across a range of ambient light conditions, sponge saturation, saline contamination, and initial blood Hb. Utilization of this tool could significantly improve the accuracy of blood loss estimates.

Clinical evaluation of a novel system for monitoring surgical hemoglobin loss

BACKGROUND

Accurate measurement of intraoperative blood loss is an important clinical variable in managing fluid resuscitation and avoiding unnecessary transfusion of blood products. In this study, blood lost onto laparotomy sponges during surgical cases was measured using a tablet computer programmed with a unique algorithm modeled after facial recognition technology. In this study, we assessed the accuracy and performance of the system in surgical cases.

METHODS

In this prospective, multicenter study, 46 patients undergoing surgery with anticipated significant blood loss contributed laparotomy sponges for hemoglobin (Hb) loss measurement using the Triton System with Feature Extraction Technology (Gauss Surgical, Inc., Los Altos, CA). The Hb loss measured by the new system was compared with that measured by manual rinsing of the sponges. Accuracy was evaluated using linear regression and Bland-Altman analysis. In addition, the new system's calculation of blood volume loss was compared with the gravimetric method of estimating blood loss from intraoperative sponge weights.

RESULTS

A significant positive linear correlation was noted between the new system's measurements and the rinsed Hb mass (r = 0.93, P < 0.0001). Bland-Altman analysis revealed a bias of 9.0 g and narrow limits of agreement (-7.5 to 25.5 g) between the new system's measures and the rinsed Hb mass. These limits were within the clinically relevant difference of ±30 g, which is approximately half of the Hb content of a unit of allogeneic whole blood. Bland-Altman analysis of the estimated blood loss on sponges using the gravimetric method demonstrated a bias of 466 mL (overestimation) with limits of agreement of -171 and 1103 mL, due to the presence of contaminants other than blood on the laparotomy sponges.

CONCLUSIONS

The novel mobile monitoring system provides an accurate measurement of Hb mass on surgical sponges as compared with that of manual rinsing measurements and is significantly more accurate than the gravimetric method. Further study is warranted to assess the clinical use of the technology.

Comparison of the hemostatic efficacy of low-volume lyophilized plasma reconstituted using sterile water, lactated Ringer's, normal saline, and Hextend solutions

BACKGROUND

Low-volume ascorbic acid-buffered reconstituted lyophilized plasma (LP) provides logistic advantages, reduces the risks for large-volume resuscitation, modulates inflammation, and is equally effective for hemostatic resuscitation as full-volume LP. We compared the physiologic effects of resuscitation using LP reconstituted with sterile water (LP-SW), lactated Ringer's solution (LP-LR), normal saline (LP-NS), and Hextend (LP-Hx).

METHODS

Plasma was collected from swine, lyophilized, and then reconstituted into four test solutions: LP-SW, LP-LR, LP-NS, or LP-Hx. Forty swine were anesthetized and subjected to a validated model of polytrauma and hemorrhagic shock (including a Grade V liver injury), then randomized to receive one of the four test solutions. Physiologic parameters, blood loss, lactate, and hematocrit were followed up. Coagulation status was evaluated using thrombelastography. Inflammatory mediator expression was evaluated by multiplex serum assay.

RESULTS

Forty animals were included in the study (10 animals per group). One animal died following LP-Hx resuscitation. There was less blood loss in the LP-SW and LP-LR groups compared with the LP-NS and LP-Hx groups (p < 0.05). The LP-SW group exhibited less early coagulopathic changes by thrombelastography, and the LP-Hx group had persistently elevated international normalized ratios at the end of the study period (p < 0.05). Serum interleukin 6 was lower after 4 hours in the LP-SW group compared with LP-NS (p < 0.05).

CONCLUSION

Resuscitation using low-volume LP-SW and LP-LR buffered with ascorbic acid confers an anti-inflammatory benefit and results in less blood loss. Sterile water is a safe, cost-effective, and universally available fluid for creating a low-volume hemostatic LP resuscitation solution.

Comparisons of lactated Ringer's and Hextend resuscitation on hemodynamics and coagulation following femur injury and severe hemorrhage in pigs

BACKGROUND

This study compared coagulation function after resuscitation with Hextend and lactated Ringer's (LR) solution in pigs with tissue injury and hemorrhagic shock.

METHODS

Pigs were randomized into control (n = 7 each), LR, and Hextend groups. Femur fracture was induced using the captive bolt stunner at midshaft of the pigs' left legs, followed by hemorrhage of 60% total blood volume and resuscitation with either Hextend (equal to bled volume) or LR to reach the same mean arterial pressure. Pigs in the control group were not bled or resuscitated. Hemodynamics was monitored hourly for 6 hours. Blood samples were taken at baseline (BL), after hemorrhage, 15 minutes, 3 hours, and 6 hours after resuscitation for blood and coagulation measurements.

RESULTS

Mean arterial pressure decreased to 50% of BL by the 60% hemorrhage but returned to near BL within 1 hour after LR or Hextend resuscitation. Heart rate was increased (from 91 ± 4 beats per minute to 214 ± 20 beats per minute) by hemorrhage and decreased after resuscitation but remained elevated above BL in both groups. Resuscitation with Hextend (42 mL/kg) or LR (118 ± 3 mL/kg) reduced hematocrit, total protein, fibrinogen, and platelet counts, with greater decreases shown in the Hextend group. Clot strength was lower but returned to BL by 3 hours in the LR group, whereas it remained reduced for the 6-hour period after Hextend. The overall clotting capacity after LR was decreased after hemorrhage and resuscitation but returned to BL by 3 hours, whereas it remained low after Hextend for the 6-hour experiment period.

CONCLUSION

After traumatic hemorrhage, coagulation function was restored within 6 hours with LR resuscitation but not with Hextend. The lack of recovery after Hextend is likely caused by greater hemodilution and possible effects of starches on coagulation substrates and further documents the need to restrict the use of high-molecular-weight starch in resuscitation fluids for bleeding casualties.

Hydroxyethyl starch for fluid resuscitation in critically ill patients

BACKGROUND

Intravenous fluid therapy is one of the most frequent interventions provided to patients in the intensive care unit; however, the type of fluid (i.e., crystalloid or colloid) used for resuscitation remains controversial. The most common type of colloid administered to resuscitate critically ill patients is hydroxyethyl starch (HES); however, its safety and efficacy have not been rigorously evaluated in large pragmatic randomized trials, and emerging data have accumulated to question its potential for toxic adverse effects.

OBJECTIVE

To evaluate the efficacy and safety of HES for fluid resuscitation in critically ill patients with a focus on survival and kidney function.

DESIGN

Multicentre (32 sites in Australia and New Zealand) blinded randomized controlled parallel-group trial.

METHODS

Seven thousand eligible adult patients (age - ≥ 18 yr) admitted to an intensive care unit and judged by their treating clinician to require fluid resuscitation were included in the study. Study treatment allocation used encrypted Web-based randomization stratified by site and an admission diagnosis of trauma.

INTERVENTION

Randomized patients were assigned to receive either 6% HES with a molecular weight of 130 kD and molar substitution ratio of 0.4 (130/0.4; Voluven(®), Fresenius Kabi) in 0.9% sodium chloride or 0.9% sodium chloride (saline) in indistinguishable Free flex 500 mL bags until intensive care unit (ICU) discharge, death, or 90 days after randomization. According to registration guidelines, the study fluid was administered to a maximum dose of 50 mL kg(-1) body weight per day and followed, if necessary, by open-label saline during the remaining 24-hr period.

MEASUREMENTS

The primary efficacy outcome was death within 90 days after randomization. The key secondary outcomes were incidence of acute kidney injury (AKI), defined by the RIFLE (Risk, Injury, Failure, Loss, Endstage) criteria; treatment with renal replacement therapy(RRT); development of new organ dysfunction, defined by the sequential organ failure assessment score; duration of mechanical ventilation; duration of RRT; cause-specific mortality; and adverse events. Tertiary outcomes were ICU and hospital lengths of stay and ICU and hospital mortality. The primary outcome was evaluated across six a prior idefined subgroups: urine output criteria for AKI; presence of sepsis; presence of trauma, with or without traumatic brain injury; acute physiology and chronic health evaluation (APACHE) score C ≥ 25; and receipt of HES prior to randomization.

MAIN RESULTS

The HES and saline groups had similar characteristics at baseline. The average age was 63 yr, 60.4% of patients were male, and 42.7% were admitted to the ICU after surgery (54.7% after elective surgery). The median [interquartile range] APACHE II score was 17[12.0-23.0] with a score C ≥ 25 in 18.2%. Sepsis and trauma were primary diagnoses in 28.8% and 7.9% of patients, respectively. Mechanical ventilation was received by 64.5% of patients, vasopressor therapy by 45.8%, and HES fluid prior to randomization by 15.1%. Enrolment occurred approximately 11 hr after ICU admission. During the first four days after randomization, the mean (standard deviation) study fluid received by the HES group was less when compared with the saline group [526 (425) mL day(-1) vs 616 (488) mL day(-1), respectively; P < 0.001]. Mortality at 90 days was 18.0% in patients receiving HES (597/3,315) and 17.0% in those receiving saline (566/3,336) (relative risk [RR] for HES, 1.06; 95% confidence interval (CI), 0.96 to 1.18; P = 0.26). There was no significant difference in 90-day mortality across the six a priori defined subgroups. Renal replacement therapy was received in 7.0% of patients in the HES group (235/3,352) and 5.8% of patients in the saline group (196/3,376) (RR for HES, 1.21; 95% CI, 1.00 to 1.45; P = 0.04). In the HES and saline groups, RIFLE - Injury occurred in 34.6% and 38.0% of patients,respectively (P = 0.005), and RIFLE - Failure occurred in 10.4% and 9.2% of patients, respectively (P = 0.12). There were no differences in mortality in ICU, in hospital, or at 28 days. Hydroxyethyl starch was associated with a decrease in new cardiovascular organ failure compared with saline (36.5% vs 39.9%, respectively; RR 0.91; 95% CI, 0.84 to 0.99; P = 0.03) and an increase in new hepatic organ failure compared with saline (1.9% vs 1.2%, respectively; RR 15.6; 95% CI, 1.03 to 2.36; P = 0.03). There were no differences between HES and saline for days in ICU or hospital or for duration of mechanical ventilation or RRT. Hydroxyethyl starch was associated with more adverse events compared with saline (5.3% vs 2.8%, respectively; RR 1.86; 95% CI, 1.46 to 2.38; P < 0.001). Adverse events were predominantly accounted for by pruritis and skin rash.

CONCLUSION

In critically ill patients receiving fluid resuscitation, there was no significant difference in 90-day mortality between 6% HES (130/0.4) or saline. Even so, more patients who received resuscitation with HES were treated with RRT and experienced adverse events.

Consensus statement of the ESICM task force on colloid volume therapy in critically ill patients

PURPOSE

Colloids are administered to more patients than crystalloids, although recent evidence suggests that colloids may possibly be harmful in some patients. The European Society of Intensive Care Medicine therefore assembled a task force to compile consensus recommendations based on the current best evidence for the safety and efficacy of the currently most frequently used colloids--hydroxyethyl starches (HES), gelatins and human albumin.

METHODS

Meta-analyses, systematic reviews and clinical studies of colloid use were evaluated for the treatment of volume depletion in mixed intensive care unit (ICU), cardiac surgery, head injury, sepsis and organ donor patients. Clinical endpoints included mortality, kidney function and bleeding. The relevance of concentration and dosage was also assessed. Publications from 1960 until May 2011 were included. The quality of available evidence and strength of recommendations were based on the Grading of Recommendations Assessment, Development, and Evaluation (GRADE) approach.

RECOMMENDATIONS AND CONCLUSIONS

We recommend not to use HES with molecular weight ≥ 200 kDa and/or degree of substitution >0.4 in patients with severe sepsis or risk of acute kidney injury and suggest not to use 6% HES 130/0.4 or gelatin in these populations. We recommend not to use colloids in patients with head injury and not to administer gelatins and HES in organ donors. We suggest not to use hyperoncotic solutions for fluid resuscitation. We conclude and recommend that any new colloid should be introduced into clinical practice only after its patient-important safety parameters are established.

The effect of acute autologous blood transfusion on coagulation dysfunction after cardiopulmonary bypass

OBJECTIVE

To evaluate the influence of acute autologous blood transfusion on postcardiopulmonary bypass coagulation disturbances evaluated by thromboelastography (TEG) as a point-of-care test.

METHODS

This prospective randomized controlled study included consecutive patients who underwent elective cardiac surgery with cardiopulmonary bypass. The patients in group A underwent acute autologous blood transfusion with acute normovolemic haemodilution and those in group H received homologous blood, if needed, and served as controls.

RESULTS

A total of 62 patients, from 68 enrolled, completed the study: 27 in group A and 35 in group H. Both groups had similar prolongation of prothrombin time and partial thromboplastin time, decreased platelets count and changes in postoperative thromboelastographic variables. There were no differences between them for postoperative bleeding, blood transfusions or haemoglobin values. There was significant prolongation of the R value of TEG (without heparinase) in both groups at 4 h after surgery compared with the immediate postoperative values: from 11.3 +/- 4.2 to 12.3 +/- 5.5 mm, P < 0.05 for group A and from 9.9 +/- 3.7 to 12.5 +/- 5.4 mm, P < 0.01 for group H. The R values of TEG with and without heparinase differed significantly (P < 0.05) at 4 h postoperatively.

CONCLUSION

Autologous blood transfusion of 15% estimated blood volume did not affect postcardiopulmonary bypass coagulopathy, nor did it decrease blood loss or homologous blood and its products transfusion in the early postoperative period. TEG is a valuable measure for detecting coagulation dysfunction with a potential role in the postoperative management of cardiac patients.