Colloid solutions: a clinical update

The effect of goal-directed crystalloid versus colloid administration on postoperative spirometry parameters: a substudy of a randomized controlled clinical trial

BACKGROUND

Pulmonary function is impaired after major abdominal surgery and might be less impaired by restrictive fluid administration. Under the assumption of a fluid-sparing effect of colloids, we tested the hypothesis that an intraoperative colloid-based goal-directed fluid management strategy impairs postoperative pulmonary function parameters less compared to goal-directed crystalloid administration.

METHODS

We performed a preplanned, single-center substudy within a recently published trial evaluating the effect of goal-directed crystalloids versus colloids on a composite of major complications. Sixty patients undergoing major open abdominal surgery were randomized to Doppler-guided intraoperative fluid replacement therapy with lactated Ringer's solution (n = 31) or unbalanced 6% hydroxyethyl starch 130/0.4 (n = 29). A blinded investigator performed bedside spirometry (Spirobank-G, Medical International Research, Rome, Italy) preoperatively as well as 6, 24, and 48 h postoperatively.

RESULTS

Median total intraoperative fluid requirements were significantly higher during crystalloid administration compared to patients receiving colloids (4567 ml vs. 3044 ml, p = 0.01). Six hours after surgery, pulmonary function parameters did not differ significantly between the crystalloid - and the colloid group: forced vital capacity (FVC): 1.6 l (1.2-2 l) vs. 1.9 l (1.5-2.4 l), p = 0.15; forced expiratory volume in 1 second (FEV1): 1.1 l (0.9-1.6 l) vs. 1.4 l (1.2-1.7 l), p = 0.18; and peak expiratory flow (PEF): 2 l.sec-1 (1.5 - 3.6 l.sec -1) vs. 2.3 l.sec -1 (1.8 - 3.4 l.sec -1), p = 0.23. Moreover, postoperative longitudinal time × group interactions of FVC, FEV1, and PEF between 6 and 48 postoperative hours did not differ significantly.

CONCLUSION

Postoperative pulmonary function parameters were similarly impaired in patients receiving goal-directed crystalloid administration as compared to goal-directed colloid administration during open abdominal surgery.

TRIAL REGISTRATION

ClinicalTrials.gov ( NCT00517127 , registered on August 16, 2007) and EudraCT (2005-004602-86).

Recent Advances in the Development of Tetrazine Ligation Tools for Pretargeted Nuclear Imaging

Tetrazine ligation has gained interest as a bio-orthogonal chemistry tool within the last decade. In nuclear medicine, tetrazine ligation is currently being explored for pretargeted approaches, which have the potential to revolutionize state-of-the-art theranostic strategies. Pretargeting has been shown to increase target-to-background ratios for radiopharmaceuticals based on nanomedicines, especially within early timeframes. This allows the use of radionuclides with short half-lives which are more suited for clinical applications. Pretargeting bears the potential to increase the therapeutic dose delivered to the target as well as reduce the respective dose to healthy tissue. Combined with the possibility to be applied for diagnostic imaging, pretargeting could be optimal for theranostic approaches. In this review, we highlight efforts that have been made to radiolabel tetrazines with an emphasis on imaging.

Emerging nanotechnologies for targeting antimicrobial resistance

Antimicrobial resistance is a leading cause of mortality worldwide. Without newly approved antibiotics and antifungals being brought to the market, resistance is being developed to the ones currently available to clinicians. The reason is the applied evolutionary pressure to bacterial and fungal species due to the wide overuse of common antibiotics and antifungals in clinical practice and agriculture. Biofilms harbour antimicrobial-resistant subpopulations, which make their antimicrobial treatment even more challenging. Nanoparticle-based technologies have recently been shown to successfully overcome antimicrobial resistance in both planktonic and biofilms phenotypes. This results from the combination of novel nanomaterial research and classic antimicrobial therapies which promise to deliver a whole new generation of high-performance active nanocarrier systems. This review discusses the latest developments of promising nanotechnologies with applications against resistant pathogens and evaluates their potential and feasibility for use in novel antimicrobial therapies.

The effect of HES130/0.4 sodium chloride solution on kidney function following early fluid resuscitation in shock patients

Background

Doctors often use a small dose of hydroxyethyl starch (HES) 130/0.4 sodium chloride solution in the emergency room; however, its effect on kidney function remains controversial. This study aimed to evaluate the effect of a small dose of HES130/0.4 sodium chloride solution on kidney function in shock patients during early fluid resuscitation.

Methods

This cohort study retrospectively analyzed the data of 129 shock patients requiring fluid resuscitation who had been admitted to the Emergency Department of the Affiliated Hospital of Nantong University from January 2019 to December 2020. Patients were divided into the observation group (n=40) and control group (n=89) according to the type of fluid resuscitation. In relation to the fluid resuscitation treatment, the observation group was treated with crystalloid solution, while the control group was treated with crystalloid and HES130/0.4 sodium chloride solution. To further explore the effect of a small dose of HES130/0.4 sodium chloride solution, the patients were further divided into the following 4 groups based on the specific fluid administered: (I) the HES(+), lactated Ringer's (LR)(+) group (n=85); (II) the HES(+), LR(-) group (n=4); (III) the HES(-), LR(+) group (n=31); and (IV) the HES(-), LR(-) group (n=9). The outcomes were in-hospital mortality and changes in creatinine (CR) level after fluid resuscitation.

Results

There were no significant differences in the in-hospital mortality rates between the observation and control groups (P=0.343). The CR levels of patients in the control and HES(+), LR(+) groups were reduced after fluid resuscitation (P=0.034; P=0.028). There was no significant change in patients' CR levels in the HES(+), LR(-) group after fluid resuscitation (P=0.999).

Conclusions

Administering a small dose of HES 130/0.4 sodium chloride in patients with shock does not appear to affect kidney function and in-hospital mortality; however, these findings should be considered exploratory, and further studies should be conducted to confirm these results.

Stage 1-Biomarkers of Kidney Injury in Dogs Undergoing Constant Rate Infusion of Hydroxyethyl Starch 130/0.4

In veterinary medicine, investigations relating the effects of hydroxyethyl starch (HES) on renal function report contrasting results. This study aimed to assess the changes in the selected biomarkers of kidney injury in dogs after the administration of HES 130/0.4 as a constant rate infusion (CRI) for 24 h. Ten adult client-owned dogs with hypoalbuminemia (albumin < 2 g/dL) and ongoing fluid losses were included. Enrolled dogs received intravenous fluid therapy with crystalloids and a CRI of HES 130/0.4 at a dose of 2 mL/kg/h for 24 h. Serum creatinine (sCr), fractional excretion (FE) of electrolytes, urinary protein to creatinine ratio (UPC), urinary albumin to creatinine ratio (UAC), SDS-page, and urinary neutrophil gelatinase-associated lipocalin (uNGAL) were measured at the baseline before HES infusion, and after 24 h (T24) and 48 h (T48) from the baseline. No statistically significant difference was found between the baseline value vs. T24 and the baseline vs. T48 for sCr, UAC, UPC, FE of sodium, chloride and calcium, and uNGAL. A significant increase in FEK (p = 0.04) was noticed between the baseline and T48. In this study sample of hypoalbuminemic dogs, HES 130/0.4 at the dose and rate of infusion applied did not cause any significant changes in the investigated biomarkers of kidney injury.

Perioperative hemodynamic optimization in laparoscopic sleeve gastrectomy using stroke volume variation to reduce postoperative nausea and vomiting

BACKGROUND

Risk of postoperative nausea and vomiting (PONV) is usually high among patients undergoing laparoscopic sleeve gastrectomy (LSG). Perioperative hemodynamic optimization using goal-directed fluid therapy (GDFT) based on stroke volume variation (SVV) has been suggested to reduce PONV.

OBJECTIVES

This study aimed to investigate the effectiveness of GDFT on reducing PONV.

SETTING

The operating rooms in China Medical University Hospital.

METHODS

This prospective cohort study included 75 patients undergoing LSG. Patients were randomized into 3 groups: controls (conventional fluid therapy), GDFT-hydroxyethyl starch (GH), and GDFT-lactated Ringer's (GL) groups. In both GDFT groups, optimization of fluid administration was achieved by continuous monitoring and adjusting of SVV. Severity of PONV was evaluated using a standardized questionnaire. Other clinically relevant events, including in-hospital surgical site infections and length of hospital stay were also investigated.

RESULTS

In the GH group, the total volume of fluid administered intraoperatively was significantly lower than that in the GL and control groups (P < .001). Assessment of PONV severity showed a significantly higher score at postoperative 24 hours in the GH group (P < .05), while no significant differences were found between the 3 groups at postoperative 48 hours. No significant differences were observed between the 3 groups in surgical site infections and length of hospital stay.

CONCLUSION

No significant benefit is found in reducing PONV by using GDFT in patients undergoing LSG, although GDFT effectively avoids excessive volume of fluid administration. PONV incidence appears to be higher with intraoperative colloid infusion for GDFT during LSG. Further investigation is warranted to elucidate the mechanism underlying PONV in postoperative LSG.

Effects of hydroxyethyl starch and gelatin on the risk of acute kidney injury following orthotopic liver transplantation: A multicenter retrospective comparative clinical study

Objectives

This multicenter retrospective study aimed to compare the effects of HES and gelatin (GEL) on the risk of post-OLT AKI.

Method

A total of 1,672 patients undergoing OLT were enrolled from major transplant centers in China between 2005 and 2013. These patients were divided into three groups: GEL, hydroxyethyl starch (HES), and GEL + HES group.

Results

There was no significant difference in the incidence of post-OLT AKI among the GEL, HES, and GEL + HES groups. The GEL + HES group had a lower incidence of stage II post-OLT AKI than the other two groups. Compared with patients receiving GEL, patients receiving HES did not harbor an increased risk of AKI. Our results showed that MELD score (adjusted odds ratio [OR], 1.579; 95% confidence interval [CI], 1.123–2.219; P = 0.009) and preoperative anemia (adjusted OR, 1.533; 95% CI, 1.212–1.939; P < 0.001) were independent risk factors for post-OLT AKI, and normal preoperative Scr level (vs abnormal; adjusted OR, 0.402; 95% CI, 0.222–0.729; P = 0.003) was independent protective factors for post-OLT AKI.

Conclusion

This large-scale multicenter retrospective study found that the intraoperative use of HES did not increase the overall incidence of post-OLT AKI in patients when compared with GEL, and whether to increase the risk of post-OLT AKI needs to be further explored.

Intraoperative Fluid Management in Patients Undergoing Spine Surgery: A Narrative Review

Fluid management has been widely recognized as an important component of the perioperative care in patients undergoing major procedures including spine surgeries. Patient- and surgery-related factors such as age, length of the surgery, massive intraoperative blood loss, and prone positioning, may impact the intraoperative administration of fluids. In addition, the type of fluid administered may also affect post-operative outcomes. Published literature describing intraoperative fluid management in patients undergoing major spine surgeries is limited and remains controversial. Therefore, we reviewed current literature on intraoperative fluid management and its association with post-operative complications in spine surgery.

Effect of Intraoperative Goal-directed Balanced Crystalloid versus Colloid Administration on Major Postoperative Morbidity

Editor’s Perspective

What We Already Know about This Topic

What This Article Tells Us That Is New

Background

Crystalloid solutions leave the circulation quickly, whereas colloids remain for hours, thus promoting hemodynamic stability. However, colloids are expensive and promote renal toxicity in critical care patients. This study tested the hypothesis that goal-directed colloid administration during elective abdominal surgery decreases 30-day major complications more than goal-directed crystalloid administration.

Methods

In this parallel-arm double-blinded multicenter randomized trial, adults having moderate- to high-risk open and laparoscopically assisted abdominal surgery with general anesthesia were randomly assigned to Doppler-guided intraoperative volume replacement with 6% hydroxyethyl starch 130/0.4 (n = 523) or lactated Ringer’s solution (n = 534). The primary outcome was a composite of serious postoperative cardiac, pulmonary, infectious, gastrointestinal, renal, and coagulation complications that were assessed with a generalized estimating equation multivariate model. The primary safety outcome was a change in serum creatinine concentration up to 6 months postoperatively, compared to baseline concentrations.

Results

A total of 1,057 patients were included in the analysis. Patients assigned to crystalloid received a median [quartile 1, quartile 3] amount of 3.2 l [2.3, 4.4] of crystalloid, and patients assigned to colloid received 1.0 l [0.5, 1.5] of colloid and 1.8 l [1.2, 2.4] of crystalloid. The estimated intention-to-treat common effect relative risk for the primary composite was 0.90 for colloids versus crystalloids (95% CI: 0.65 to 1.23, P = 0.51), and 18% (91 of 523) of colloid patients and 20% (103 of 534) of crystalloid patients incurred at least one component of the primary outcome composite. There was no evidence of renal toxicity at any time.

Conclusions

Doppler-guided intraoperative hydroxyethyl starch administration did not significantly reduce a composite of serious complications. However, there was also no indication of renal or other toxicity.

Comparison of the effects of albumin and crystalloid on mortality among patients with septic shock: systematic review with meta-analysis and trial sequential analysis

BACKGROUND

This study aimed to compare the effects on mortality of albumin and crystalloid, used for fluid resuscitation among adult patients with septic shock, through conducting a meta-analysis and trial sequential analysis (TSA).

DESIGN AND SETTING

Meta-analysis and TSA conducted at Shanghai Jiao Tong University Affiliated Sixth People's Hospital, Shanghai, China.

METHODS

Data were collected from several major databases including MEDLINE, EMBASE, Clinical Trials.gov and Cochrane Central Register of Controlled Trials. Studies that compared the effects of albumin therapy versus crystalloid therapy on mortality among adult septic shock patients were eligible for inclusion in the analyses. The study name, year of publication, country of the trial, albumin concentration, type of crystalloid and all reported mortalities at different follow-up endpoints were extracted.

RESULTS

Compared with crystalloid, albumin did not decrease all-cause mortality at the final follow-up. However, in TSA, the required information size was not achieved in all groups, which means that the effect size was not definitive and further RCTs are needed to confirm or deny these findings.

CONCLUSIONS

Compared with crystalloid solutions, albumin was unable to decrease all-cause mortality. However, TSA indicated that these results could be false-negative. Additional randomized controlled trials are needed to clarify this discrepancy.

The effects of hydroxyethyl starch and gelatine on pulmonary cytokine production and oedema formation

Recently, side effects of plasma expanders like hydroxyethyl starch and gelatine gained considerable attention. Most studies have focused on the kidneys; lungs remain unconsidered. Isolated mouse lungs were perfused for 4 hours with buffer solutions based on hydroxyethyl starch (HES) 130/0.4, HES 200/0.5 or gelatine and ventilated with low or high pressure under physiological pH and alkalosis. Outcome parameters were cytokine levels and the wet-to-dry ratio. For cytokine release, murine and human PCLS were incubated in three different buffers and time points.In lungs perfused with the gelatine based buffer IL-6, MIP-2 and KC increased when ventilated with high pressure. Wet-to-dry ratios increased stronger in lungs perfused with gelatine - compared to HES 130/0.4. Alkalotic perfusion resulted in higher cytokine levels but normal wet-to-dry ratio. Murine PCLS supernatants showed increased IL-6 and KC when incubated in gelatine based buffer, whereas in human PCLS IL-8 was elevated. In murine IPL HES 130/0.4 has lung protective effects in comparison to gelatine based infusion solutions, especially in the presence of high-pressure ventilation. Gelatine perfusion resulted in increased cytokine production. Our findings suggest that gelatine based solutions may have side effects in patients with lung injury or lung oedema.

Does small-volume resuscitation with crystalloids or colloids influence hemostasis and survival of rabbits subjected to lethal uncontrolled hemorrhage?

BACKGROUND

Prehospital, small-volume resuscitation of combat casualties with a synthetic colloid (6% hydroxyethyl starch [HES] 670/0.75) has been recommended when blood or blood components are unavailable. We studied hemostatic effects of a newer synthetic colloid (6% HES, 130/0.4) compared with either a natural colloid (albumin) or to crystalloids in an uncontrolled hemorrhage model.

METHODS

Spontaneously breathing New Zealand white rabbits (3.4 ± 0.1 kg) were anesthetized, instrumented, and subjected to a splenic injury with uncontrolled bleeding. Fifteen minutes after injury, rabbits were in shock (mean arterial pressure [MAP] = 26 ± 1.3 mm Hg, and received colloids (6% HES, 130/0.4 or 5% albumin at 15 mL/kg), or crystalloids (normal saline at 30 mL/kg or 5% hypertonic saline at 7.5 mL/kg) for resuscitation in two intravenous bolus injections (15 minutes apart) to raise their MAP to 65 mm Hg, n = 9/group. Animals were monitored for 2.5 hours or until death, and blood losses were measured. Blood samples were analyzed for arterial blood gas, complete blood count, and coagulation measures.

RESULTS

There were no differences among groups in baseline measures and initial hemorrhage volume (11.9 ± 0.6 mL/kg) at 15 minutes postinjury. Twenty minutes after fluid resuscitation (1 hour postinjury), MAP was higher, shock indices were lower, and blood pH was higher in colloids versus. crystalloids groups (p < 0.05). Administration of 6% HES 130/0.4 colloid produced the largest hemodilution (54% decrease in hematocrit, p < 0.05 vs. hypertonic saline). Activated partial thromboplastin time increased approximately 35% above baseline in all groups except in 6% HES 130/0.4 group in which it doubled. Clot strength was reduced (15%) only in the 6% HES 130/0.4 group. 6% HES 130/0.4 resuscitation produced the largest blood loss and 33% survival rate that was not different than the crystalloid groups. Albumin produced the best hemostatic and survival outcomes (78%).

CONCLUSION

Small-volume resuscitation with crystalloids appeared inadequate to treat hypovolemic shock and prevent death. 6% HES 130/0.4 was effective hemodynamically but detrimental to hemostasis. Albumin produced the best outcomes consistent with our previous observations. Further studies are needed to prove benefit of albumin solution as a possible resuscitation fluid for treating combat casualties at the point of injury.

Prevalence of and risk factors for intraoperative gastroesophageal reflux and postanesthetic vomiting and diarrhea in dogs undergoing general anesthesia

OBJECTIVE

To determine the prevalence of intraoperative gastroesophageal reflux (GER) and postanesthetic vomiting and diarrhea, and to evaluate risk factors associated with these gastrointestinal disorders (GID) in dogs undergoing general anesthesia.

DESIGN

Prospective observational study.

SETTING

University teaching hospital.

ANIMALS

Two hundred thirty-seven client-owned dogs undergoing general inhalant anesthesia for diagnostic or surgical purposes.

INTERVENTIONS

None MEASUREMENTS AND MAIN RESULTS: Patient, surgical, and anesthetic variables, and postanesthetic treatments administered in the immediate postanesthesia period were evaluated in relation to GID using univariate and multivariate logistic regression analysis (P < 0.05). Seventy-nine of the 237 (33.4%) dogs developed GID during the perianesthetic period. The prevalences of GER, vomiting, and diarrhea were 17.3%, 5.5%, and 10.5%, respectively. Intraabdominal surgery (P = 0.016; odds ratio [OR] 2.82, 95% confidence interval [CI]: 1.21-6.62), changes in body position (P = 0.003; OR 3.17, 95% CI: 1.47-6.85), and length of anesthesia (P = 0.052; OR 1.006, 95% CI: 1.000-1.013) were associated with GER. Changes in the ventilation mode during surgery (P = 0.011; OR 6.54, 95% CI: 1.8-23.8), length of anesthesia (P = 0.024; OR 1.001, 95% CI: 1.001-1.020), and rescue synthetic colloid support due to hypotension (P = 0.005; OR 6.9, 95% CI: 1.82-26.3) were positively associated with postanesthetic vomiting. On the contrary, dogs that received acepromazine as premedication were significantly less likely (P < 0.019; OR 12.3, 95% CI: 1.52-100) to vomit. Finally, length of anesthesia, changes in body position, changes in ventilation mode, or hypoxemia during the procedure tended to increase the risk (univariate model) of diarrhea during the recovery phase.

CONCLUSIONS

GID are common in dogs undergoing general anesthesia. Duration and characteristics of the procedure, anesthetic management, and changes in certain patient variables are significant risk factors for the presence of GID in the perioperative period.

The Efficacy of Dextran-40 as a Venous Thromboembolism Prophylaxis Strategy in Cytoreductive Surgery and Hyperthermic Intraperitoneal Chemotherapy

The incidence of venous thromboembolism (VTE) in peritoneal malignancies can approach 30 to 50 per cent without prophylaxis. Prophylaxis in cytoreductive surgeries (CRS) presents a challenge to preoperative heparin-based therapy because of an increased risk of coagulopathy and potential for bleeding. Herein, we report the large series of CRS and hyperthermic intraperitoneal chemotherapy receiving dextran-40 prophylaxis. Retrospective chart review of peritoneal malignancies patients undergoing CRS at University of Nebraska Medical Center identified 69 individuals who received dextran-40 between 2010 and 2013. The incidences of VTEs, perioperative bleeding, complications, morbidity, and mortality were determined in-hospital and at 90 days. Of the 69 patients treated, the 30-day VTE rate was 8.7 per cent, and no pulmonary embolisms, bleeding, anaphylactoid reaction, or mortality were observed with dextran usage. The specific VTE events included three upper extremity and three lower extremity VTEs. No additional VTE events were identified between 30 and 90 days. In conclusion, dextran-40 prophylaxis was not associated with any perioperative bleeding events, and the observed incidence of VTE was comparable to reported heparin-based prophylaxis in CRS/hyperthermic intraperitoneal chemotherapy patients. This data supports further exploration of dextran-40 as a VTE prophylactic agent in complex surgical oncology cases.

Impact of Albumin on Coagulation Competence and Hemorrhage During Major Surgery: A Randomized Controlled Trial

For patients exposed to a massive blood loss during surgery, maintained coagulation competence is important. It is less obvious whether coagulation competence influences bleeding during elective surgery where patients are exposed to infusion of a crystalloid or a colloid. This randomized controlled trial evaluates whether administration of 5% human albumin (HA) or lactated Ringer solution (LR) affects coagulation competence and in turn blood loss during cystectomy due to bladder cancer. Forty patients undergoing radical cystectomy were included to receive either 5% HA (n = 20) or LR (n = 20). Nineteen patients were analyzed in the HA group and 20 patients in the lactated Ringer group. Blinded determination of the blood loss was similar in the 2 groups of patients: 1658 (800-3300) mL with the use of HA and 1472 (700-4330) mL in the lactated Ringer group (P = 0.45). Yet, by thrombelastography (TEG) evaluated coagulation competence, albumin affected clot growth (TEG-angle 69 ± 5 vs 74° ± 3°, P < 0.01) and strength (TEG-MA: 59 ± 6 vs 67 ± 6 mm, P < 0.001) more than LR. Furthermore, by multivariate linear regression analyses reduced TEG-MA was independently associated with the blood loss (P = 0.042) while administration of albumin was related to the changes in TEG-MA (P = 0.029), aPPT (P < 0.022), and INR (P < 0.033). This randomized controlled trial demonstrates that administration of HA does not affect the blood loss as compared to infusion of LR. Also the use of HA did not affect the need for blood transfusion, the incidence of postoperative complications, or the hospital in-stay. Yet, albumin decreases coagulation competence during major surgery and the blood loss is related to TEG-MA rather than to plasma coagulation variables.

Fluid therapy for septic shock resuscitation: which fluid should be used?

Early resuscitation of septic shock patients reduces the sepsis-related morbidity and mortality. The main goals of septic shock resuscitation include volemic expansion, maintenance of adequate tissue perfusion and oxygen delivery, guided by central venous pressure, mean arterial pressure, mixed or central venous oxygen saturation and arterial lactate levels. An aggressive fluid resuscitation, possibly in association with vasopressors, inotropes and red blood cell concentrate transfusion may be necessary to achieve those hemodynamic goals. Nonetheless, even though fluid administration is one of the most common interventions offered to critically ill patients, the most appropriate type of fluid to be used remains controversial. According to recently published clinical trials, crystalloid solutions seem to be the most appropriate type of fluids for initial resuscitation of septic shock patients. Balanced crystalloids have theoretical advantages over the classic solutions, but there is not enough evidence to indicate it as first-line treatment. Additionally, when large amounts of fluids are necessary to restore the hemodynamic stability, albumin solutions may be a safe and effective alternative. Hydroxyethyl starches solutions must be avoided in septic patients due to the increased risk of acute renal failure, increased need for renal replacement therapy and increased mortality. Our objective was to present a narrative review of the literature regarding the major types of fluids and their main drawbacks in the initial resuscitation of the septic shock patients.

Fluid resuscitation and vasopressors in severe trauma patients

PURPOSE OF REVIEW

To discuss the fluid resuscitation and the vasopressor support in severe trauma patients.

RECENT FINDINGS

A critical point is to prevent a potential increase in bleeding by an overly aggressive resuscitative strategy. Indeed, large-volume fluid replacement may promote coagulopathy by diluting coagulation factors. Moreover, an excessive level of mean arterial pressure may induce bleeding by preventing clot formation.

SUMMARY

Fluid resuscitation is the first-line therapy to restore intravascular volume and to prevent cardiac arrest. Thus, fluid resuscitation before bleeding control must be limited to the bare minimum to maintain arterial pressure to minimize dilution of coagulation factors and complications of over fluid resuscitation. However, a strategy of low fluid resuscitation needs to be handled in a flexible way and to be balanced considering the severity of the hemorrhage and the transport time. A target systolic arterial pressure of 80-90 mmHg is recommended until the control of hemorrhage in trauma patients without brain injury. In addition to fluid resuscitation, early vasopressor support may be required to restore arterial pressure and prevent excessive fluid resuscitation. It is crucial to find the best alchemy between fluid resuscitation and vasopressors, to consider hemodynamic monitoring and to establish trauma resuscitative protocols.

Hydroxyethyl starch versus other fluids for non-septic patients in the intensive care unit: a meta-analysis of randomized controlled trials

INTRODUCTION

Use of hydroxyethyl starch (HES) in septic patients is reported to increase the mortality and incidence of renal replacement therapy (RRT). However, whether or not use of HES would induce the same result in non-septic patients in the intensive care unit (ICU) remains unclear. The objective of this meta-analysis was to evaluate 6% HES versus other fluids for non-septic ICU patients.

METHODS

Randomized controlled trials (RCTs) were searched from Pubmed, OvidSP, Embase database and Cochrane Library, published before November, 2013. A meta-analysis was made on the effect of 6% HES versus other fluids for non-septic ICU patients, including mortality, RRT incidence, bleeding volume, red blood cell (RBC) transfusion and fluid application for non-septic patients in ICU.

RESULTS

Twenty-two RCTs were included, involving 6,064 non-septic ICU patients. Compared with the other fluids, 6% HES was not associated with decreased overall mortality (RR = 1.03, 95%CI: 0.09 to 1.17; P = 0.67; I(2) = 0). There was no significant difference in RRT incidence, bleeding volume and red blood cell transfusion between 6% HES group and the other fluid groups. However, patients in HES group received less total intravenous fluids than those receiving crystalloids during the first day in ICU (SMD = -0.84; 95%CI: -1.39 to -0.30; P = 0.003, I(2) = 74%).

CONCLUSIONS

This meta-analysis found no increased mortality, RRT incidence, bleeding volumes or RBC transfusion in non-septic ICU patients, but the sample sizes were small and the studies generally were of poor quality.

Pros and cons of tetrastarch solution for critically ill patients

Proper fluid management is crucial for the management of critically ill patients. However, there is a continuing debate about the choice of the fluid, i.e., crystalloid vs. colloid. Colloid solution is theoretically advantageous to the crystalloid because of larger volume effect and less interstitial fluid accumulation, and hydroxyethyl starch (HES) is most frequently used for perioperative setting. Nevertheless, application of HES solution is relatively limited due to its side effects including renal toxicity and coagulopathy. Since prolonged presence of large HES molecule is responsible for these side effects, rapidly degradable HES solution with low degree of substitution (tetrastarch) supposedly has less potential for negative effects. Thus, tetrastarch may be more frequently used in the ICU setting. However, several large-scale randomized trials reported that administration of tetrastarch solution to the patients with severe sepsis has negative effects on mortality and renal function. These results triggered further debate and regulatory responses around the world. This narrative review intended to describe the currently available evidence about the advantages and disadvantages of tetrastarch in the ICU setting.

Six percent hydroxyethyl starch 130/0.4 (Voluven®) versus 5% human serum albumin for volume replacement therapy during elective open-heart surgery in pediatric patients

BACKGROUND

Although 5% albumin (human serum albumin [HSA]) is widely used in cardiac surgery children, synthetic colloids may provide a valuable alternative. This study compared 6% hydroxyethyl starch (HES) 130/0.4 with HSA for volume replacement in this population.

METHODS

The study was a two-center, randomized, controlled, parallel-group, double-blind trial performed in children aged 2-12 yr undergoing elective surgery for congenital heart disease under extracorporeal circulation. The primary objective was to demonstrate equivalence between HES and HSA with regard to the total volume of colloid infusion for intraoperative volume replacement including priming of the extracorporeal circuitery.

RESULTS

In the per-protocol population, mean volume of colloid required until end of surgery was (mean ± SD) 36.6 ± 11.8 ml/kg body weight in the HES group (N = 29) and 37.0 ± 11.9 ml/kg body weight in the HSA group (N = 26; ratio of means HES/HSA = 0.98 [95% CI, 0.84-1.16]). Intraoperative fluid balance was less positive in the HES group (P = 0.047). No difference was found regarding hemodynamics, the use of vasoactive and inotropic drugs. Blood loss, erythrocytes transfusion, and renal function were not different between groups. The incidence of adverse events up to postoperative day 28 did not differ between the groups.

CONCLUSIONS

In pediatric cardiac surgery, HES showed equivalence to HSA with regard to volume replacement therapy in children aged from 2 to 12 yr. Although there was no suggestion of an imbalance of safety measures between HES and HSA, the study was not powered to provide any firm conclusions about safety of tetrastarch in this population.

Low molecular weight pentastarch is more effective than crystalloid solution in goal-directed fluid management in patients undergoing major gastrointestinal surgery

BACKGROUND

This prospective observational study compared the volume effect between hydroxyethyl starch (HES) and crystalloid solution and its context dependency in intraoperative goal-directed fluid management.

METHODS

With institutional review board (IRB) approval, 35 patients undergoing major gastrointestinal surgery were enrolled. Fluid challenge consisting of 250 ml of either bicarbonate Ringer solution (BRS) or low molecular weight pentastarch (HES 70/0.5) was given to maintain stroke volume index >35 ml/m2. The context of fluid challenge was classified as related to either epidural block (EB) or blood loss (BL) or as nonspecific. The primary end point was the interval between index fluid challenge and the next fluid challenge, and the secondary end point was the hemodynamic parameter at the end of fluid challenge. Differences in these parameters in each clinical context were compared between BRS and HES 70/0.5. A p value <0.05 was considered statistically significant.

RESULTS

Eighty-eight, 77, and 127 fluid challenges were classified as related to EB and BL and as nonspecific, respectively. In the nonspecific condition, the median (range) interval after fluid challenge with HES 70/0.5 and BRS was 45 (11-162) min and 18 (8-44) min, respectively, and the difference was statistically significant. Also, mean arterial pressure and stroke volume index significantly increased, whereas stroke volume variation significantly decreased after fluid challenge with HES 70/0.5 compared with BRS. Such differences were not observed in the other situations.

CONCLUSIONS

HES 70/0.5 exerted larger volume effects than did crystalloid under nonspecific conditions. However, similar volume effects were observed during volume loss and extensive sympathetic blockade.

Acute Normovolemic Hemodilution in the Pig Is Associated with Renal Tissue Edema, Impaired Renal Microvascular Oxygenation, and Functional Loss

Background:

The authors investigated the impact of acute normovolemic hemodilution (ANH) on intrarenal oxygenation and its functional short-term consequences in pigs.

Methods:

Renal microvascular oxygenation (µPo2) was measured in cortex, outer and inner medulla via three implanted optical fibers by oxygen-dependent quenching of phosphorescence. Besides systemic hemodynamics, renal function, histopathology, and hypoxia-inducible factor-1α expression were determined. ANH was performed in n = 18 pigs with either colloids (hydroxyethyl starch 6% 130/0.4) or crystalloids (full electrolyte solution), in three steps from a hematocrit of 30% at baseline to a hematocrit of 15% (H3).

Results:

ANH with crystalloids decreased µPo2 in cortex and outer medulla approximately by 65% (P &lt; 0.05) and in inner medulla by 30% (P &lt; 0.05) from baseline to H3. In contrast, µPo2 remained unaltered during ANH with colloids. Furthermore, renal function decreased by approximately 45% from baseline to H3 (P &lt; 0.05) only in the crystalloid group. Three times more volume of crystalloids was administered compared with the colloid group. Alterations in systemic and renal regional hemodynamics, oxygen delivery and oxygen consumption during ANH, gave no obvious explanation for the deterioration of µPo2 in the crystalloid group. However, ANH with crystalloids was associated with the highest formation of renal tissue edema and the highest expression of hypoxia-inducible factor-1α, which was mainly localized in distal convoluted tubules.

Conclusions:

ANH to a hematocrit of 15% statistically significantly impaired µPo2 and renal function in the crystalloid group. Less tissue edema formation and an unimpaired renal µPo2 in the colloid group might account for a preserved renal function.

Effects of synthetic colloids on oxidative stress and inflammatory response in hemorrhagic shock: comparison of hydroxyethyl starch 130/0.4, hydroxyethyl starch 200/0.5, and succinylated gelatin

INTRODUCTION

This study compared the effects of hydroxyethyl starch 130/0.4, hydroxyethyl starch 200/0.5, and succinylated gelatin on oxidative stress and the inflammatory response in a rodent hemorrhagic shock model.

METHODS

Sodium pentobarbital-anesthetized adult male Wistar rats (200 g to 220 g) were subjected to a severe volume-controlled hemorrhage using arterial blood withdrawal (30 mL/kg to 33 mL/kg) and resuscitated with a colloid solution at the same volume as blood withdrawal (hydroxyethyl starch 130/0.4, hydroxyethyl starch 200/0.5, or succinylated gelatin). Arterial blood gas parameters were monitored. Malondialdehyde (MDA) content and myeloperoxidase (MPO) activity in the liver, lungs, intestine, and brain were measured two hours after resuscitation. The levels of tumor necrosis factor-alpha (TNF-α) and interleukin-6 in the intestine were also measured.

RESULTS

Infusions of hydroxyethyl starch 130/0.4, but not hydroxyethyl starch 200/0.5 or succinylated gelatin, significantly reduced MDA levels and MPO activity in the liver, intestine, lungs and brain, and it also inhibited the production of TNF-α in the intestine two hours after resuscitation. However, no significant difference between hydroxyethyl starch 200/0.5 and succinylated gelatin was observed.

CONCLUSIONS

Hydroxyethyl starch 130/0.4, but not hydroxyethyl starch 200/0.5 or succinylated gelatin, treatment after hemorrhagic shock ameliorated oxidative stress and the inflammatory response in this rat model. No significant differences were observed after hydroxyethyl starch 200/0.5 or succinylated gelatin administration at doses of approximately 33 mL/kg.

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

BACKGROUND AND OBJECTIVES

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

METHODS

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

RESULTS

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

CONCLUSION

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

Clinical utility of intra-operative 6% hydroxyethyl starch (130 / 0.4) supplementation in hypoxemic femur injury patients: a preliminary report of twenty cases

Abstract

Posttraumatic intravasation of fat and debris can lead to a cascade of events. Hydroxyethyl starches (HES) markedly suppress neutrophil influx by decreasing pulmonary capillary permeability and facilitating tissue oxygenation by improving microcirculation. It was hypothesized that in hypoxemic femur injury patients undergoing operative stabilization, HES administration will prevent the deterioration of respiratory variables and facilitates recovery. This prospective, double-blind, randomized preliminary study, enrolled twenty posttraumatic hypoxemic patients (room air PaO2 < 70 mmHg, Schonfeld fat embolism index score (SS) > 5) scheduled for femur fracture stabilization under general anesthesia. Patients were allocated to receive either; 6% HES 130/0.42, 15 mL/kg or 0.9% normal saline (NS) to maintain their central venous pressure (CVP) 12 + 2 mm Hg. Blood was transfused according to the maximum allowable blood loss and by serial hematocrit estimations. Perioperative Glasgow Coma Scale (GCS), physiological variables, arterial oxygen saturation (SpO2), arterial blood gas (ABG), SS and P/F ratios were recorded until recovery. The partial pressure of oxygen in arterial blood / fraction of inspired oxygen ratio (PaO2/FiO2) improved from a preoperative value of 273.33 ± 13.05 to 435.70 in the 6% Hydroxyethyl starch group (HES) and from 275.24 ± 15.34 to 302.25 ± 70.35 in the NS group over a period of six days (P values =0.970, 0.791, 0.345, 0.226, 0.855, 0.083, 0.221). Time taken to achieve a P/F ratio > 300 and for persistent reduction of Murray’s lung injury score (LIS) were comparable (P = 0.755 and 0.348, respectively). The number of ventilator, intensive care unit (ICU) and hospital stay days, did not differ (P value = 0.234, 1.00, 0. 301, respectively). There were no adverse sequelae or mortalities. A trend showing relatively fast improvement in the P/F ratio and an early reduction in LIS values was observed in hypoxemic, femur injury patients receiving intraoperative colloid supplementation.

Anaphylaxis induced by hydroxyethyl starch during general anesthesia -A case report-

Hydroxyethyl starch (HES) solutions are synthetic non-protein colloid solutions used to treat hypovolemia. However, their use is not free from the risk of allergic reactions. A 42-year-old male was scheduled to undergo aortic-iliac-femoral bypass surgery for the treatment of arteriosclerosis obliterans. He had no history of allergy. Two hours after the start of surgery, and within minutes after HES administration, facial erythema, hypotension and bronchospasm developed. HES infusion was discontinued under the estimation of anaphylaxis. The patient received phenylephrine, ephedrine, diphenhydramine and hydrocortisone with hydration. After restoration of vital signs, surgery was performed without complications.

Pharmaceutical aspects of the recombinant human serum albumin dimer: structural characteristics, biological properties, and medical applications

Human serum albumin is the most abundant protein in the blood. It is clinically used in the treatment of severe hypoalbuminemia and as a plasma expander. The use of albumins as a carrier for drugs is currently being developed, and some are now in the preclinical and clinical trial stages. The main technologies for utilizing an albumin as a drug carrier are protein fusion, polymerization and surface modification, and so on. Among these technologies, albumin dimerization has wide clinical applications as a plasma expander as well as a drug carrier. Despite the fact that many reports have appeared on drugs using an albumin dimer as a carrier, our knowledge of the characteristics of the albumin dimer itself is incomplete. In this review, we summarize the structural characteristics of recombinant albumin dimers produced by two methods, namely, chemical linkage with 1,6-bis(maleimido)hexane and genetically linked with an amino acid linker, and the physicochemical characteristics and biological properties of these preparations. Finally, the potential for pharmaceutical applications of albumin dimers in clinical situations is discussed.

Reactive polymer enables efficient in vivo bioorthogonal chemistry

There has been intense interest in the development of selective bioorthogonal reactions or "click" chemistry that can proceed in live animals. Until now however, most reactions still require vast surpluses of reactants because of steep temporal and spatial concentration gradients. Using computational modeling and design of pharmacokinetically optimized reactants, we have developed a predictable method for efficient in vivo click reactions. Specifically, we show that polymer modified tetrazines (PMT) are a key enabler for in vivo bioorthogonal chemistry based on the very fast and catalyst-free [4 + 2] tetrazine/trans-cyclooctene cycloaddition. Using fluorescent PMT for cellular resolution and (18)F labeled PMT for whole animal imaging, we show that cancer cell epitopes can be easily reacted in vivo. This generic strategy should help guide the design of future chemistries and find widespread use for different in vivo bioorthogonal applications, particularly in the biomedical sciences.

Revised Starling equation and the glycocalyx model of transvascular fluid exchange: an improved paradigm for prescribing intravenous fluid therapy

I.V. fluid therapy does not result in the extracellular volume distribution expected from Starling's original model of semi-permeable capillaries subject to hydrostatic and oncotic pressure gradients within the extracellular fluid. Fluid therapy to support the circulation relies on applying a physiological paradigm that better explains clinical and research observations. The revised Starling equation based on recent research considers the contributions of the endothelial glycocalyx layer (EGL), the endothelial basement membrane, and the extracellular matrix. The characteristics of capillaries in various tissues are reviewed and some clinical corollaries considered. The oncotic pressure difference across the EGL opposes, but does not reverse, the filtration rate (the 'no absorption' rule) and is an important feature of the revised paradigm and highlights the limitations of attempting to prevent or treat oedema by transfusing colloids. Filtered fluid returns to the circulation as lymph. The EGL excludes larger molecules and occupies a substantial volume of the intravascular space and therefore requires a new interpretation of dilution studies of blood volume and the speculation that protection or restoration of the EGL might be an important therapeutic goal. An explanation for the phenomenon of context sensitivity of fluid volume kinetics is offered, and the proposal that crystalloid resuscitation from low capillary pressures is rational. Any potential advantage of plasma or plasma substitutes over crystalloids for volume expansion only manifests itself at higher capillary pressures.

Human serum albumin: from bench to bedside

Human serum albumin (HSA), the most abundant protein in plasma, is a monomeric multi-domain macromolecule, representing the main determinant of plasma oncotic pressure and the main modulator of fluid distribution between body compartments. HSA displays an extraordinary ligand binding capacity, providing a depot and carrier for many endogenous and exogenous compounds. Indeed, HSA represents the main carrier for fatty acids, affects pharmacokinetics of many drugs, provides the metabolic modification of some ligands, renders potential toxins harmless, accounts for most of the anti-oxidant capacity of human plasma, and displays (pseudo-)enzymatic properties. HSA is a valuable biomarker of many diseases, including cancer, rheumatoid arthritis, ischemia, post-menopausal obesity, severe acute graft-versus-host disease, and diseases that need monitoring of the glycemic control. Moreover, HSA is widely used clinically to treat several diseases, including hypovolemia, shock, burns, surgical blood loss, trauma, hemorrhage, cardiopulmonary bypass, acute respiratory distress syndrome, hemodialysis, acute liver failure, chronic liver disease, nutrition support, resuscitation, and hypoalbuminemia. Recently, biotechnological applications of HSA, including implantable biomaterials, surgical adhesives and sealants, biochromatography, ligand trapping, and fusion proteins, have been reported. Here, genetic, biochemical, biomedical, and biotechnological aspects of HSA are reviewed.

Hypoalbuminaemia in the perioperative period: clinical significance and management options

Albumin has been the focus of literally thousands of articles since its first use in the clinical setting during World War II. Despite being at the centre of several clinical controversies, many questions still remain regarding the use and abuse of albumin. The major physiologic functions include maintaining colloid osmotic pressure, binding and transport of metabolically active molecules, serving as an antioxidant, use as a surrogate marker of nutritional status and predictor of outcome in elective surgical populations, having an anti-thrombotic influence on platelets, aiding in acid-base balance and having a protective influence on capillary membrane integrity. Albumin will continue to be widely used in clinical medicine despite many of the drawbacks. It now appears the benefits in the use of albumin in most cases outweigh the risks. The clinical implications of hypoalbuminaemia as an indicator of surgical or intensive care unit (ICU) outcome or nutritional status is clearly disease- and organ specific. The use of albumin as a volume expander appears to have limited, if any, benefit over crystalloid. The "secondary" benefits of albumin in specific surgical and intensive-care conditions, such as sepsis and organ dysfunction, are numerous and are well supported in the current literature.