Influence of different volume replacement strategies on inflammation and endothelial activation in the elderly undergoing major abdominal surgery

Monitoring Pre- and Post-Operative Immune Alterations in Patients With Locoregional Colorectal Cancer Who Underwent Laparoscopy by Single-Cell Mass Cytometry

Surgical excision is currently the principal therapy for locoregional colorectal cancer (CRC). However, surgical trauma leads to controlled tissue damage, causing profound alterations in host immunity and, in turn, affecting post-operative outcomes. Surgery-induced immune alterations in CRC remain poorly defined. Here, single-cell mass cytometry was applied to serial blood samples collected pre-operatively, and on days 1, 3, and 7 post-operatively from 24 patients who underwent laparoscopic surgical resection of CRC to comprehensively monitor the perioperative phenotypic alterations in immune cells and dynamics of immune response. Characterization of immune cell subsets revealed that the post-operative immune response is broad but predominantly suppressive, supported by the decreases in total frequencies of circulating T cells and natural killer (NK) cells, as well as decreased HLA-DR expression on circulating monocytes. The proportion of T cells significantly decreased on day 1 and recovered to the pre-surgical level on day 3 after surgery. The frequency of monocytes was significantly elevated on day 1 after surgery and declined to baseline level on day 3. NK cells temporarily contracted on post-operative day 3. T cells, monocytes, DCs, NK cells, and B cells were partitioned into phenotypically different single-cell clusters. The dynamics of single-cell clusters were different from those of the bulk lineages. T cell clusters in the same response phase fluctuate inconsistently during the perioperative period. Comparing to the baseline levels, the frequencies of CD11b(+)CD33(+)CD14(+)CD16(−) classical monocytes expanded followed by contraction, whereas CD11b(+)CD33(+)CD14(high)CD16(low) intermediate monocytes remained unchanged; HLA-DR expression in monocytes were significantly reduced; the frequencies of intermediate CD56(bright)CD16(+) NK cell subsets increased; and the percentage of memory B lymphocytes were elevated after surgery. Post-operative pro- and anti-inflammatory cytokines were both altered. Furthermore, perioperative immune perturbations in some of the cell subsets were unrecovered within seven days after surgery. Chronological monitoring major immune lineages provided an overview of surgery-caused alterations, including cell augments and contractions and precisely timed changes in immune cell distribution in both innate and adaptive compartments, providing evidence for the interaction between tumor resection and immune modulation.

Ethical publishing in intensive care medicine: A narrative review

Ethical standards in the context of scientific publications are increasingly gaining attention. A narrative review of the literature concerning publication ethics was conducted as found in PubMed, Google Scholar, relevant news articles, position papers, websites and other sources. The Committee on Publication Ethics has produced guidelines and schedules for the handling of problem situations that have been adopted by professional journals and publishers worldwide as guidelines to authors. The defined requirements go beyond the disclosure of conflicts of interest or the prior registration of clinical trials. Recommendations to authors, editors and publishers of journals and research institutions were formulated with regard to issues of authorship, double publications, plagiarism, and conflicts of interest, with special attention being paid to unethical research behavior and data falsification. This narrative review focusses on ethical publishing in intensive care medicine. As scientific misconduct with data falsification damage patients and society, especially if fraudulent studies are considered important or favor certain therapies and downplay their side effects, it is important to ensure that only studies are published that have been carried out with highest integrity according to predefined criteria. For that also the peer review process has to be conducted in accordance with the highest possible scientific standards and making use of available modern information technology. The review provides the current state of recommendations that are considered to be most relevant particularly in the field of intensive care medicine.

Inflammatory mediators in intra-abdominal sepsis or injury - a scoping review

Introduction

Inflammatory and protein mediators (cytokine, chemokine, acute phase proteins) play an important, but still not completely understood, role in the morbidity and mortality of intra-abdominal sepsis/injury. We therefore systematically reviewed preclinical and clinical studies of mediators in intra-abdominal sepsis/injury in order to evaluate their ability to: (1) function as diagnostic/prognostic biomarkers; (2) serve as therapeutic targets; and (3) illuminate the pathogenesis mechanisms of sepsis or injury-related organ dysfunction.

Methods

We searched MEDLINE, PubMed, EMBASE and the Cochrane Library. Two investigators independently reviewed all identified abstracts and selected articles for full-text review. We included original studies assessing mediators in intra-abdominal sepsis/injury.

Results

Among 2437 citations, we selected 182 studies in the scoping review, including 79 preclinical and 103 clinical studies. Serum procalcitonin and C-reactive protein appear to be useful to rule out infection or monitor therapy; however, the diagnostic and prognostic value of mediators for complications/outcomes of sepsis or injury remains to be established. Peritoneal mediator levels are substantially higher than systemic levels after intra-abdominal infection/trauma. Common limitations of current studies included small sample sizes and lack of uniformity in study design and outcome measures. To date, targeted therapies against mediators remain experimental.

Conclusions

Whereas preclinical data suggests mediators play a critical role in intra-abdominal sepsis or injury, there is no consensus on the clinical use of mediators in diagnosing or managing intra-abdominal sepsis or injury. Measurement of peritoneal mediators should be further investigated as a more sensitive determinant of intra-abdominal inflammatory response. High-quality clinical trials are needed to better understand the role of inflammatory mediators.

Electronic supplementary material

The online version of this article (doi:10.1186/s13054-015-1093-4) contains supplementary material, which is available to authorized users.

Hydroxyethyl starch 130/0.38-0.45 versus crystalloid or albumin in patients with sepsis: systematic review with meta-analysis and trial sequential analysis

OBJECTIVE

To assess the effects of fluid therapy with hydroxyethyl starch 130/0.38-0.45 versus crystalloid or albumin on mortality, kidney injury, bleeding, and serious adverse events in patients with sepsis.

DESIGN

Systematic review with meta-analyses and trial sequential analyses of randomised clinical trials.

DATA SOURCES

Cochrane Library, Medline, Embase, Biosis Previews, Science Citation Index Expanded, CINAHL, Current Controlled Trials, Clinicaltrials.gov, and Centerwatch to September 2012; hand search of reference lists and other systematic reviews; contact with authors and relevant pharmaceutical companies.

STUDY SELECTION

Eligible trials were randomised clinical trials comparing hydroxyethyl starch 130/0.38-0.45 with either crystalloid or human albumin in patients with sepsis. Published and unpublished trials were included irrespective of language and predefined outcomes.

DATA EXTRACTION

Two reviewers independently assessed studies for inclusion and extracted data on methods, interventions, outcomes, and risk of bias. Risk ratios and mean differences with 95% confidence intervals were estimated with fixed and random effects models.

RESULTS

Nine trials that randomised 3456 patients with sepsis were included. Overall, hydroxyethyl starch 130/0.38-0.45 versus crystalloid or albumin did not affect the relative risk of death (1.04, 95% confidence interval 0.89 to 1.22, 3414 patients, eight trials), but in the predefined analysis of trials with low risk of bias the relative risk of death was 1.11 (1.00 to 1.23, trial sequential analysis (TSA) adjusted 95% confidence interval 0.95 to 1.29, 3016 patients, four trials). In the hydroxyethyl starch group, renal replacement therapy was used more (1.36, 1.08 to 1.72, TSA adjusted 1.03 to 1.80, 1311 patients, five trials), and the relative risk of acute kidney injury was 1.18 (0.99 to 1.40, TSA adjusted 0.90 to 1.54, 994 patients, four trials). More patients in the hydroxyethyl starch group were transfused with red blood cells (1.29, 1.13 to 1.48, TSA adjusted 1.10 to 1.51, 973 patients, three trials), and more patients had serious adverse events (1.30, 1.02 to 1.67, TSA adjusted 0.93 to 1.83, 1069 patients, four trials). The transfused volume of red blood cells did not differ between the groups (mean difference 65 mL, 95% confidence interval -20 to 149 mL, three trials).

CONCLUSION

In conventional meta-analyses including recent trial data, hydroxyethyl starch 130/0.38-0.45 versus crystalloid or albumin increased the use of renal replacement therapy and transfusion with red blood cells, and resulted in more serious adverse events in patients with sepsis. It seems unlikely that hydroxyethyl starch 130/0.38-0.45 provides overall clinical benefit for patients with sepsis.

Fibrinogen/LDL apheresis is a promising rescue therapy for sudden sensorineural hearing loss

BACKGROUND

Fibrinogen/LDL apheresis has been proven to be effective in treatment of sudden sensorineural hearing loss (SSNH). This study is aimed to investigate if reduction of fibrinogen and serum LDL is also effective in patients with SSNH non-responding toward treatment with corticosteroids and plasmaexpanders.

METHODS

Remission rates of 217 patients suffering from SSHL were investigated after treatment with apheresis. All patients were non-responders after other therapies such as high doses of steroids or plasmaexpanders.

RESULTS

Single apheresis resulted in complete or partial remissions in 61% of patients when given after other unsuccessful conducted therapies such as corticosteroids and plasmaexpanders.

CONCLUSION

Fibrinogen/LDL apheresis is a promising rescue therapy for sudden sensorineural hearing loss even after unsuccessful other therapies.

Fluid resuscitation with 6% hydroxyethyl starch (130/0.4) in acutely ill patients: an updated systematic review and meta-analysis

BACKGROUND

Recent research suggests that 6% hydroxyethyl starch (HES) 130/0.4 is one of the most frequently used resuscitation fluids worldwide. The retraction of studies evaluating its use necessitates a reevaluation of available evidence regarding its safety and efficacy.

METHODS

We performed a systematic review and meta-analysis of unretracted randomized controlled trials comparing the effects of 6% HES 130/0.4 with other colloid or crystalloid solutions on mortality, acute kidney injury/failure, and bleeding in acutely ill or perioperative patients. A sensitivity analysis including the data from retracted studies was also conducted.

RESULTS

Overall, 36 studies reporting 2149 participants met the inclusion criteria, of which 11 (n = 541) have been retracted. Of the remaining 25 studies, there was a high risk of bias in 17 studies; 19 studies (n = 1246) were conducted in perioperative patients and 6 (n = 362) in critically ill patients. Sixteen studies reported mortality: 104 deaths in 1184 participants. The relative risk of death was 0.95 (95% confidence interval 0.64-1.42, I(2) = 0%, P = 0.73); including the retracted studies added a further 14 deaths and the relative risk was 0.92 (95% confidence interval 0.63-1.34, I(2) = 0%, P = 0.95). The data reporting acute kidney injury, red blood cell transfusion, and bleeding were of insufficient quantity and quality and not amenable to meta-analysis.

CONCLUSIONS

Published studies are of poor quality and report too few events to reliably estimate the benefits or risks of administering 6% HES 130/0.4. This same conclusion is reached with or without the retracted studies. Given the widespread use of 6% HES 130/0.4, high-quality trials reporting a large number of events are urgently required.

The acute effects of acetate-balanced colloid and crystalloid resuscitation on renal oxygenation in a rat model of hemorrhagic shock

INTRODUCTION

Fluid resuscitation therapy is the initial step of treatment for hemorrhagic shock. In the present study we aimed to investigate the acute effects of acetate-balanced colloid and crystalloid resuscitation on renal oxygenation in a rat model of hemorrhagic shock. We hypothesized that acetate-balanced solutions would be superior in correcting impaired renal perfusion and oxygenation after severe hemorrhage compared to unbalanced solutions.

METHODS

In anesthetized, mechanically ventilated rats, hemorrhagic shock was induced by withdrawing blood from the femoral artery until mean arterial pressure (MAP) was reduced to 30 mmHg. One hour later, animals were resuscitated with either hydroxyethyl starch (HES, 130/0.42 kDa) dissolved in saline (HES-NaCl; n=6) or a acetate-balanced Ringer's solution (HES-RA; n=6), as well as with acetated Ringer's solution (RA; n=6) or 0.9% NaCl alone (NaCl; n=6) until a target MAP of 80 mmHg was reached. Oxygen tension in the renal cortex (CμPO2), outer medulla (MμPO2), and renal vein were measured using phosphorimetry.

RESULTS

Hemorrhagic shock (MAP=30 mmHg) significantly decreased renal oxygenation and oxygen consumption. Restoring the MAP to 80 mmHg required 24.8±1.7 ml of NaCl, 21.7±1.4 ml of RA, 5.9±0.5 ml of HES-NaCl (p<0.05 vs. NaCl and RA), and 6.0±0.4 ml of HES-RA (p<0.05 vs. NaCl and RA). NaCl, RA, and HES-NaCl resuscitation led to hyperchloremic acidosis, while HES-RA resuscitation did not. Only HES-RA resuscitation could restore renal blood flow back to ∼85% of baseline level (from 1.9±0.1 ml/min during shock to 5.1 ml±0.2 ml/min 60 min after HES-RA resuscitation) which was associated with an improved renal oxygenation (CμPO2 increased from 24±2 mmHg during shock to 50±2 mmHg 60 min after HES-RA resuscitation) albeit not to baseline level. At the end of the protocol, creatinine clearance was decreased in all groups with no differences between the different resuscitation groups.

CONCLUSION

While resuscitation with the NaCl and RA (crystalloid solutions) and the HES-NaCl (unbalanced colloid solution) led to hyperchloremic acidosis, resuscitation with the HES-RA (acetate-balanced colloid solution) did not. The HES-RA was furthermore the only fluid restoring renal blood flow back to ∼85% of baseline level and most prominently improved renal microvascular oxygenation.

Cholecystectomy in the very elderly--is 90 the new 70?

BACKGROUND

Nonagenarians are the fastest growing sector of population across Western Europe. Although prevalence of gallstone disease is high, elective cholecystectomy is still controversial in this age group.

METHODS

A retrospective chart review was conducted of cholecystectomies done in patients over 90 years of age at our institution between 2004 and December 2009. During this period, a total of 3,009 cholecystectomies were performed on patients of all ages. Data collected included demographics, patient comorbidities, indications for surgery, type of surgery performed, intraoperative findings, histology, perioperative morbidity and mortality.

RESULTS

Twenty-two nonagenarians (18 females) underwent cholecystectomy during the study period. Of these patients, 19 patients (86%) had diabetes, 16 (73%) had hypertension, and 10 (45%) had coronary artery disease. Twenty patients (91%) underwent an emergency procedure. In two patients, cholecystectomy was indicated for non-resolving pain after attempted conservative therapy, only two patients were operated electively. Laparoscopic cholecystectomy was attempted in 13 patients (59%), 3 patients needed a conversion, and 9 patients (41%) considered unfit to undergo a laparoscopic approach had an open procedure. Mean operation time was 83 min. Histology showed gangrenous cholecystitis in six (27%) patients. The mean length of stay was 10 days (4-23 days). Two patients (8.3%) required intensive care following surgery. There were no common bile duct injuries, one patient had a cystic stump leak. One patient died in the postoperative period (4.6%). All patients with an emergency operation were classified as at least ASA III. Conversion rate, percentage of open procedures, percentage of advanced histology, ASA score, and hospital stay were significantly higher when compared to all patients.

CONCLUSION

Our study demonstrates that in unselected nonagenarians,cholecystectomy is safe with acceptable perioperative morbidity and mortality even as an emergency procedure. However, our data also suggests that cholecystitis appears to be a neglected condition in this age group.

Hydroxyethyl starch resuscitation reduces the risk of intra-abdominal hypertension in severe acute pancreatitis

OBJECTIVES

This study aimed to address whether hydroxyethyl starch (HES) is beneficial for intra-abdominal pressure (IAP) in severe acute pancreatitis (SAP) in early stages.

METHODS

Forty-one patients with SAP were randomized to HES group (n = 20) and the Ringer's lactate (RL) group (n = 21). The groups received 6% HES 130/0.4 for 8 days and RL solution without colloid, respectively. The primary end point was the IAP. The secondary end points were fluid balance, major organ complications, the Acute Physiology and Chronic Heath Evaluation II score, and the serum levels of C-reactive protein, interleukin-6, and interleukin-8.

RESULTS

The characteristics of baseline data were similar in the 2 groups. In the HES group, the IAP was significantly lower in 2 to 7 days, and fewer patients received mechanical ventilation (15.0% vs 47.6%). A negative fluid balance was observed earlier in the HES group than in the RL group (2.5 ± 2.2 vs 4.0 ± 2.5 days).

CONCLUSIONS

Fluid resuscitation with HES in the early stages of SAP can decrease the risk of intra-abdominal hypertension and reduce the use of mechanical ventilation.

Association of 6% hetastarch resuscitation with adverse outcomes in critically ill trauma patients

BACKGROUND

Six percent hetastarch is used as a volume expander but has been associated with poor outcomes. The aim of this study was to evaluate trauma patients resuscitated with hetastarch.

METHODS

A retrospective review was performed of adult trauma patients. Demographics, injury severity, laboratory values, outcomes, and hetastarch use were recorded.

RESULTS

A total of 2,225 patients were identified, of whom 497 (22%) received hetastarch. There were no differences in age, gender, injury mechanism, lactate, hematocrit, or creatinine. The mean injury severity score was different: 29.7 ± 12.6 with hetastarch versus 27.5 ± 12.6 without hetastarch. Acute kidney injury developed in 65 hetastarch patients (13%) and in 131 (8%) without hetastarch (relative risk, 1.73; 95% confidence interval [CI], 1.30-2.28). Hetastarch mortality was 21%, compared with 11% without hetastarch (relative risk, 1.84; 95% CI, 1.48-2.29). Multivariate logistic regression demonstrated hetastarch use (odds ratio, 1.96; 95% CI, 1.49-2.58) as independently significant for death. Hetastarch use was independently significant for renal dysfunction as well (odds ratio, 1.70; 95% CI, 1.22-2.36).

CONCLUSIONS

Because of the detrimental association with renal function and mortality, hetastarch should be avoided in the resuscitation of trauma patients.

Beneficial effects of hyperoncotic albumin on liver injury and survival in peritonitis-induced sepsis rats

Liver injury/dysfunction developing in patients with sepsis may lead to an increased risk of death. Small-volume resuscitation with hyperoncotic albumin (HA) has been proposed to restore physiologic hemodynamics in hemorrhagic and septic shock. We evaluated whether HA resuscitation could alleviate the development of liver injury/dysfunction in rats with polymicrobial sepsis induced by cecal ligation and puncture (CLP). The male Wistar rats received 0.9% saline or HA (25%, 3 mL/kg intravenously) at 3 h after CLP or sham operation. All hemodynamic and biochemical variables were measured during the 18-h observation. After 18 h of CLP, the septic rats developed circulatory failure (i.e., hypotension, tachycardia, and poor tissue perfusion), liver injury (examined by biochemical variables and histologic studies), and a higher mortality. Hyperoncotic albumin not only ameliorated the deterioration of hemodynamic changes but also attenuated neutrophil infiltration and cell death in the liver of septic animals. The septic rats treated with HA had a higher survival when compared with those with 0.9% saline treatment. Moreover, the increased plasma IL-1β, plasma IL-6, plasma nitrite/nitrate concentrations, liver iNOS expression, and liver superoxide levels in CLP rats were attenuated after administration of HA. Thus, HA may be regarded as a potential therapeutic agent in the early treatment of septic shock to prevent or reduce subsequent liver failure.

[Surgical treatment of pancreatic adenocarcinoma by cephalic duodenopancreatectomy (Part 1). Post-surgical complications in 204 cases in a reference hospital]

INTRODUCTION

Cephalic duodenopancreatectomy (CDP) is the treatment of choice in cancer of the head of the pancreas. However, it continues to have a high post-surgical morbidity and mortality. The aim of this article is to define variables that influence post-surgical morbidity and mortality after cephalic duodenopancreatectomy due to pancreatic adenocarcinoma (PA) cancer of the head of the pancreas (CHP).

MATERIAL AND METHODS

The variables were prospectively collected form patients operated on between 1991 and 2007, in order to investigate the factors of higher morbidity.

RESULTS

A total of 204 patients had been intervened due to PA, of whom 57 were older than 70 years. Of these patients, 119 had a CPD, 11 extended lymphadenectomy, 66 with pyloric conservation, and 8 with extension to total pancreatectomy due to involvement of the section margin. Portal or mesenteric vein resection was included in 35 cases. Post-surgical complications were detected in 45% of cases, the most frequent being: slow gastric emptying (20%), surgical wound infection (17%), pancreatic fistula (10%), and serious medical complications (8%). Further surgery was required in 13%, and the over post-surgical mortality was 7%. A patient age greater than 70 years, post-surgical haemoperitoneum, gastroenteric dehiscence, and the presence of medical complications were post-surgical mortality risk factors in the multivariate analysis. Pancreatic fistula was not a factor associated with post-surgical mortality.

CONCLUSIONS

Cephalic duodenopancreatectomy is a safe technique but with a considerable morbidity. Patients over 70 years of age must be carefully selected before considering surgery. Serious medical complications must be treated aggressively to avoid an unfavourable progression.

A systematic review of third-generation hydroxyethyl starch (HES 130/0.4) in resuscitation: safety not adequately addressed

BACKGROUND

Hydroxyethyl starches (HES) are widely used for intravascular volume therapy in surgical, emergency, and intensive care patients. There are safety concerns with regard to coagulopathy, renal failure, pruritus, tissue storage, and mortality. Third-generation HES 130/0.4 is considered to have an improved risk profile. A common rationale for the use of HES is the belief that 3 to 4 times more crystalloid than colloid volume is needed to achieve similar hemodynamic end points. Our goal was to assess whether published studies on HES 130/0.4 resuscitation are sufficiently well designed to draw conclusions about the safety of this compound. In addition, we wanted to assess crystalloid-to-colloid fluid ratios in studies with goal-directed fluid regimen.

METHODS

Systematic review of randomized controlled trials in which HES 130/0.4 is used for resuscitation.

RESULTS

We identified 56 randomized controlled trials (RCTs) with HES 130/0.4 in. acute hypovolemia, mainly from the elective surgical setting (n = 45). Surgical studies were small-sized (median 25 patients in the HES groups, range 10 to 90) and of short duration (median 12 hours, range 0.5 to 144 hours). The median cumulative HES dose was 2465 mL (range 328 to 6229 mL), corresponding to 35 mL/kg in a 70-kg patient, the daily dose limit being 50 mL/kg. End points mostly addressed variable surrogate outcomes. Sixty percent of control fluids were other HES solutions, gelatins, or dextran, which have a similar risk profile. Without exception, these studies were not designed for clinically important safety outcomes, primarily because they were too small, used mostly inadequate control fluids, and had inappropriately short observation periods. Therefore, and also because of heterogeneity of patient groups and outcome definitions, results from these studies cannot be pooled. These studies do not allow any conclusion about the safety of HES 130/0.4. There is a common belief that 3 to 4 times more crystalloid than colloid volume is necessary to achieve similar hemodynamic effects. We found a considerably lower ratio in surgical studies (mean 1.8, SD 0.1).

CONCLUSIONS

In summary, the extent of fluid load reduction that can be achieved by HES 130/0.4 is overestimated. Use of older HES solutions may be associated with serious side effects, and clinicians should be aware that there is no convincing evidence that third-generation HES 130/0.4 is safe in surgical, emergency, or intensive care patients despite publication of numerous clinical studies.

[Postoperative wound infections. Pathophysiology, risk factors and preventive concepts]

Postoperative wound infections are the third most common type of nosocomial infection in German emergency hospitals after pneumonia and urinary infections. They are associated with increased morbidity and mortality, prolonged hospital stay and increased costs. The most important risk factors include the microbiological state of the skin surrounding the incision, delayed or premature prophylaxis with antibiotics, duration of surgery, emergency surgery, poorly controlled diabetes mellitus, malignant disease, smoking and advanced age. Anesthesiological measures to decrease the incidence of wound infections are maintaining normothermia, strict indications for allogenic blood transfusions and timely prophylaxis with antibiotics. Blood glucose concentrations should be kept in the range of 8.3-10 mmol/l (150-180 mg/dl) as lower values are associated with increased complications. Intraoperative and postoperative hyperoxia with 80% O(2) has not been shown to effectively decrease wound infections. The application of local anesthetics into the surgical wound in clinically relevant doses for postoperative analgesia does not impair wound healing.

[Hydroxyethyl starch]

OBJECTIVE

The purpose of this review is to draw up a statement on current knowledge available on the more recent hydroxyethyl starch (HES).

DATA SOURCES

References were obtained from computerized bibliographic research (Medline), recent review articles, the library of the service and personal files.

STUDY SELECTION

All categories of articles on this topic have been selected.

DATA EXTRACTION

Articles have been analysed for biophysics, pharmacology, toxicity, side effects, clinical effects and using prospect of HES.

DATA SYNTHESIS

The first HES was made available in the United States in 1970. The development of a new generation of HES restarted the discussion on clinical interest and the limits in the use of these macromolecules. This interest is also strengthened today by the recent data attached to plasma substitution in intensive care or perioperative resuscitation. The interest for crystalloids and colloids is still widely debated, and among the latter, the relative interest of the HES last generation compared to older ones. Recent HES development is in line with a decrease molecular weight, change rate molar substitution and to amend the glucose to hydroxyethyl report. The ultimate goal is to reduce the side effects of these molecules preventing their use. Side effects are dominated by haemostasis and renal dysfunction. The latest developments are the so-called HES "balanced" solutions.

The efficacy and safety of colloid resuscitation in the critically ill

Despite evidence from clinical studies and meta-analyses that resuscitation with colloids or crystalloids is equally effective in critically ill patients, and despite reports from high-quality clinical trials and meta-analyses regarding nephrotoxic effects, increased risk of bleeding, and a trend toward higher mortality in these patients after the use of hydroxyethyl starch (HES) solutions, colloids remain popular and the use of HES solutions is increasing worldwide. We investigated the major rationales for colloid use, namely that colloids are more effective plasma expanders than crystalloids, that synthetic colloids are as safe as albumin, that HES solutions have the best risk/benefit profile among the synthetic colloids, and that the third-generation HES 130/0.4 has fewer adverse effects than older starches. Evidence from clinical studies shows that comparable resuscitation is achieved with considerably less crystalloid volumes than frequently suggested, namely, <2-fold the volume of colloids. Albumin is safe in intensive care unit patients except in patients with closed head injury. All synthetic colloids, namely, dextran, gelatin, and HES have dose-related side effects, which are coagulopathy, renal failure, and tissue storage. In patients with severe sepsis, higher doses of HES may be associated with excess mortality. The assumption that third-generation HES 130/0.4 has fewer adverse effects is yet unproven. Clinical trials on HES 130/0.4 have notable shortcomings. Mostly, they were not performed in intensive care unit or emergency department patients, had short observation periods of 24 to 48 hours, used cumulative doses below 1 daily dose limit (50 mL/kg), and used unsuitable control fluids such as other HES solutions or gelatins. In conclusion, the preferred use of colloidal solutions for resuscitation of patients with acute hypovolemia is based on rationales that are not supported by clinical evidence. Synthetic colloids are not superior in critically ill adults and children but must be considered harmful depending on the cumulative dose administered. Safe threshold doses need to be determined in studies in high-risk patients and observation periods of 90 days. Such studies on HES 130/0.4 are still lacking despite its widespread and increasing use. Because there are safer and equally effective alternatives in the form of crystalloids, use of synthetic colloids should be avoided except in the context of clinical studies.

A balanced view of balanced solutions

The present review of fluid therapy studies using balanced solutions versus isotonic saline fluids (both crystalloids and colloids) aims to address recent controversy in this topic. The change to the acid-base equilibrium based on fluid selection is described. Key terms such as dilutional-hyperchloraemic acidosis (correctly used instead of dilutional acidosis or hyperchloraemic metabolic acidosis to account for both the Henderson-Hasselbalch and Stewart equations), isotonic saline and balanced solutions are defined. The review concludes that dilutional-hyperchloraemic acidosis is a side effect, mainly observed after the administration of large volumes of isotonic saline as a crystalloid. Its effect is moderate and relatively transient, and is minimised by limiting crystalloid administration through the use of colloids (in any carrier). Convincing evidence for clinically relevant adverse effects of dilutional-hyperchloraemic acidosis on renal function, coagulation, blood loss, the need for transfusion, gastrointestinal function or mortality cannot be found. In view of the long-term use of isotonic saline either as a crystalloid or as a colloid carrier, the paucity of data documenting detrimental effects of dilutional-hyperchloraemic acidosis and the limited published information on the effects of balanced solutions on outcome, we cannot currently recommend changing fluid therapy to the use of a balanced colloid preparation.

Impact of policy change on US Army combat transfusion practices

BACKGROUND

Clinical practice guidelines (CPGs) are used to keep providers up-to-date with the most recent literature and to guide in decision making. Adherence is typically improved although many have a muted impact. In March 2006, the US Army issued a damage control resuscitation CPG, encouraging 1:1 plasma:red blood cell (RBC) transfusions and limiting crystalloid use. The objective of this study was to determine whether the CPG was associated with a change in the transfusion practices in combat-wounded patients.

METHODS

All US service members injured in Operation Iraqi Freedom/Operation Enduring Freedom who received massive transfusions (MTs; > or = 10 RBC in 24 hours) were queried from the US Army Institute of Surgical Research transfusion database. Whole blood, when used, was counted as 1 unit of RBC, fresh frozen plasma (FFP), and platelet. Subjects were divided into pre- and post-CPG cohorts. Primary outcomes were ratios of FFP:RBC and crystalloid use.

RESULTS

A total of 777 MT patients were identified. The cohorts were similar in age (25 years +/- 6 years vs. 25 years +/- 6 years; p = ns) and injury severity scale score (24 +/- 12 vs. 25 +/- 12; p = ns). The post-CPG cohort was warmer (96.5 degrees F +/- 7.8 degrees F vs. 98.2 degrees F +/- 1.9 degrees F; p < 0.05) and was transfused more RBC, platelets, and plasma but received less crystalloid (17 units +/- 12 units vs. 19 units +/- 11 units, 1 unit +/- 2 units vs. 2 units +/- 3 units, 8 units +/- 8 units vs. 14 units +/- 11 units, 14 L +/- 14 L vs. 9 L +/- 13 L, respectively; p < 0.05). The post-CPG cohort also received a higher ratio transfusion (0.5 +/- 0.31 vs. 0.8 +/- 0.31; p < 0.05) representing a change in practice. Overall mortality was not different between the two groups (24 vs. 19%; p = 0.115).

CONCLUSIONS

MT patients are now receiving a higher FFP:RBC ratio and less crystalloid after implementation of the CPG. Additionally, patients are now presenting normothermic and have higher hemoglobin levels. All of these changes are consistent with the principles of damage control resuscitation. Changes in practice were associated with implementation of the CPG, maturity of the battlefield, and increased availability of products.

Colloid vs. crystalloid infusions in gastrointestinal surgery and their different impact on the healing of intestinal anastomoses

BACKGROUND

The aim of this study was to investigate if colloid infusions have different effects on intestinal anastomotic healing when compared to crystalloid infusions depending on the amount of the administered volume.

MATERIALS AND METHODS

Twenty-eight Wistar rats were randomly assigned to four groups receiving different amounts of either a crystalloid (Cry) or a colloid (Col) infusion solution. Animals with volume restriction (Cry (-) or Col (-)) were treated with a low and animals with volume overcharge (Cry (+) or Col (+)) with a high flow rate. All animals received an infusion for a 60-min period, while an end-to-end small bowel anastomosis was performed. At reoperation, the anastomotic bursting pressure (millimeters of mercury) was measured, as well as anastomotic hydroxyproline concentration. The presence of bowel wall edema was assessed histologically.

RESULTS

Median bursting pressures were comparable in the Col (-) [118 mm Hg (range 113-170)], the Cry (-) [118 mm Hg (78-139)], and the Col (+) [97 mm Hg (65-152)] group. A significantly lower median bursting pressure was found in animals with crystalloid volume overload Cry (+) [73 mm Hg (60-101)]. Corresponding results were found for hydroxyproline concentration. Histology revealed submucosal edema in Cry (+) animals.

CONCLUSIONS

In case of a fixed, high-volume load, colloids seem to have benefits on intestinal anastomotic healing when compared to crystalloid infusions.

The evolution of an inflammatory response

BACKGROUND

The past 25 years have witnessed immense progress in our understanding of the systemic, tissue-specific, and cellular consequences of severe injury and infection. Despite such insights, considerable controversy remains regarding appropriate biologic and management interventions to prevent or ameliorate the associated adverse outcomes.

METHODS

A review of several scientific developments arising from studies initiated at Cornell University Medical College during the tenure of Dr. G. Tom Shires. The implications of those and subsequent studies are discussed.

RESULTS

An understanding of patient-specific variation and adaptability could direct individualized biologic and management interventions for severe injury and infection.

CONCLUSION

Despite more detailed appreciation of the molecular mechanisms of danger and pathogen recognition and response biology, we have much to learn about the complexity of severe injury and infection. There is a great need to extend our investigation of these mechanisms to experimental and stress-modified clinical scenarios.

The 'third space'--fact or fiction?

For decades, the 'third space' was looked upon as an actively consuming compartment. Therefore, perioperative fluid regimens were traditionally based on a generous replacement of this assumed primary loss, in addition to deficits due to insensible perspiration and fasting. The practical consequence was an extremely positive fluid balance in order to maintain blood volume during major surgery. Whereas the insensible perspiration and the preoperative deficits are in fact often negligible, and the third space appears to be only a fictional construct, the excess fluid most likely accumulates interstitially. Such shifting is related to a destruction of the endothelial glycocalyx, a key structure of the vascular barrier, by traumatic inflammation and iatrogenic hypervolaemia. This explains why patients undergoing major surgical interventions benefit significantly from an infusion regimen which does not substitute but avoids 'third-space shifting'. In summary, eradicating this notion from our minds could be a further key to achieving perioperative fluid optimisation.

The stressed host response to infection: the disruptive signals and rhythms of systemic inflammation

The cognate signals from sterile or pathogen-induced sources converge on the same recognition or response pathways. In the surgical patient, a systemic response to infection most often occurs in the context of ongoing inflammatory stress. Such an inflammatory response is modulated initially by the magnitude of injury and by patient-specific (endogenous) factors, such as confounding illness, age, and genetic variation. Over an extended period of stress, treatmentrelated (exogenous) factors add unpredictability to host responses to subsequent challenges, such as acquired infection. The host response is discussed in the context of how existing sterile stressors may modify the response to acquired infection in surgical patients.

Effects of hydroxyethyl starch resuscitation on extravascular lung water and pulmonary permeability in sepsis-related acute respiratory distress syndrome

OBJECTIVE

Hydroxyethyl starch (HES) has greater volume expansion effect and longer intravascular persistence than crystalloids. HES also decreases microvascular permeability and capillary leakage by biophysically plugging endothelial leaks, exerting an anti-inflammatory effect, and decreasing activation of endothelial cells. The aim of our study was to determine whether medium molecular weight HES (pentastarch) resuscitation in the early stage of acute respiratory distress syndrome (ARDS) simultaneously increases cardiac output without worsening pulmonary edema and whether it attenuates pulmonary vascular permeability.

DESIGN

Prospective observational study.

SETTING

Twenty-bed medical intensive care unit of a tertiary medical center.

PATIENTS

Twenty patients with early-stage ARDS.

INTERVENTION

Volume expansion with a 500-mL infusion of 10% pentastarch (HES 200/0.5) at a rate of 10 mL/kg/hr.

MEASUREMENTS AND MAIN RESULTS

Baseline hemodynamics including systemic and pulmonary artery blood pressures, central venous pressure, pulmonary artery occlusion pressure, and cardiac output were obtained from an online HP Component Monitoring System and a pulmonary artery catheter. Intrathoracic blood volume (ITBV), global end-diastolic volume, extravascular lung water (EVLW), and pulmonary vascular permeability (EVLW/ITBV) were measured with a PiCCOplus monitor. Hemodynamic measurements were repeated immediately and 2, 4, and 6 hours after volume expansion. Pentastarch loading significantly increased central venous pressure, pulmonary artery occlusion pressure, pulmonary arterial pressures, and cardiac output. Pulmonary mechanics, venous admixtures, and EVLW values remained unchanged throughout the study. EVLW/ITBV significantly decreased immediately after the pentastarch infusion.

CONCLUSIONS

In patients with early ARDS, pentastarch resuscitation significantly improved their hemodynamics and cardiac output without worsening pulmonary edema and pulmonary mechanics. It even attenuated pulmonary vascular permeability.

Impact of different crystalloid volume regimes on intestinal anastomotic stability

BACKGROUND

Anastomotic insufficiency still remains an unsolved problem in digestive surgery. Little clinical data, regarding the impact of perioperative volume management exist, which suggest lower complication rates in intestinal surgery under restrictive volume regimens. The aim of our study was to investigate the effect of the extent of intraoperative fluid administration with crystalloids on the stability of intestinal anastomoses.

MATERIAL AND METHODS

Twenty-one rats were randomly assigned to 3 experimental groups (n = 7 rats/group): control group CO (9 mL kg h crystalloid infusion), volume restriction group V (-) (3 mL kg h), and animals with volume overload V (+) (36 mL kg h). After midline incision, all animals received the corresponding infusion for a 30-minute period. Infusion was continued for further 30 minutes whereas an end-to-end small bowel anastomosis was performed 15 cm proximal to the Bauhin valve with 8 nonabsorbable interrupted inverting sutures. At reoperation on the 4th postoperative day, the anastomotic segment was dissected and the bursting pressure [mmHg] was measured. As a second parameter for the quality of anastomotic healing, hydroxyproline concentration was examined with a spectrophotometric method [microg/g dry tissue]. Histologically, structural changes of the anastomotic segments were assessed by 2 pathologists. Data are given as mean +/- SEM.

RESULTS

Anastomotic insufficiency was not seen in all animals. Bursting pressure of CO animals was 102 +/- 8 mmHg. Bursting pressure was lowest in V (+) with high volume exposure at 77 +/- 6 mmHg and significantly lower than V (-) (112 +/- 9 mmHg; P = 0.01) whereas the difference compared with the CO group did not reach significant values. Hydroxyproline concentration in V (+) (64.4 microg/g dry tissue +/- 7.7) was significantly lower compared with V (-) (91.7 microg/g dry tissue +/- 9.1) animals (P < 0.05). In all animals with volume overload a marked submucosal edema was found.

CONCLUSION

We could demonstrate for the first time in a systematic investigation, that the quantity of crystalloid infusion, applied intraoperatively, has a significant impact on functional (bursting pressure) and structural (hydroxyproline) stability of intestinal anastomoses in the early postoperative period. Because the stability and quality of an intestinal anastomosis have an impact on insufficiency rates, it should be noted that volume overload may have deleterious effects on anastomotic healing and postoperative complications in digestive surgery, possibly because of a marked bowel wall edema.

Influence of low-molecular-weight hydroxyethyl starch on microvascular permeability in patients undergoing abdominal surgery: comparison with crystalloid

PURPOSE

Adequate volume therapy is essential for stable hemodynamics and sufficient urinary output perioperatively. Hydroxyethyl starch (HES) has been reported to attenuate the microvascular hyperpermeability which occasionally occurs in surgical patients. This study was carried out to evaluate the effect of low-molecular-weight HES on the urinary microalbumin/creatinine ratio (MACR), a marker of microvascular permeability, in surgical patients.

METHODS

In a prospective, controlled, and randomized clinical trial, 21 patients undergoing abdominal surgery were divided into two groups. Group HES (n = 10) received HES at 2 ml x kg(-1) x h(-1) during surgery and at 1 ml x kg(-1) x h(-1) after surgery, and additionally they received acetated Ringer's solution (AR) at a rate to keep central venous pressure (CVP) 5 mm Hg. Group AR (n = 11) received AR at a rate to keep CVP at 3-5 mmHg. MACR, soluble intercellular adhesion molecule-1 (sICAM-1), and urinary output were measured intermittently in the perioperative period.

RESULTS

MACR was significantly increased during surgery in both groups. There was no significant difference in MACR between the two groups throughout the study period. The serum concentration of sICAM-1 decreased during surgery in both groups, and that in group HES was significantly lower than that in group AR at the end of surgery. Postoperative urinary output in group HES was greater than that in group AR. The intensive care unit (ICU) stay in group HES was shorter than that in group AR.

CONCLUSION

Although low-molecular-weight HES does not improve microvascular hyperpermeability, the expansion of the intravascular volume by HES results in higher urinary output in the postoperative period than that seen with crystalloid solution. The lower concentration of sICAM-1 after surgery may be due to hemodilution.

The inflammatory response to colloids and crystalloids used for pump priming during cardiopulmonary bypass

BACKGROUND

Systemic inflammatory response frequently occurs after coronary artery bypass surgery and is strongly correlated with the risk of postoperative morbidity and mortality. This study tests the hypothesis that the priming of the extracorporeal circuit with colloid solutions results in less inflammation in patients undergoing cardiac surgery than priming with crystalloid solutions.

METHODS

A prospective, randomized study was designed. Forty-four patients undergoing elective coronary artery bypass grafting were randomly allocated to one of two groups: 22 patients primed with Ringer's lactate (RL) solution and 22 patients primed with gelatin-containing solution during the surgery. Plasma levels of interleukin (IL)-6, IL-8, tumor necrosis factor (TNF)-alpha, C-reactive protein (CRP) and, complement 4 were measured during the surgical intervention and over the following 48 postoperative hours. Cytokine levels were measured by enzyme-linked assays from plasma samples obtained at specific time points pre- and post-operatively.

RESULTS

In both groups the serum levels of the pro-inflammatory cytokines (IL-6, IL-8, TNF-alpha), CRP, complement 4, and leukocytes increased significantly over the baseline, although no significant differences were observed between the two groups. The operation time, blood loss, need for inotropic support, extubation time, and length of intensive care unit stay did not differ significantly between the two groups.

CONCLUSION

Priming with gelatin vs. RL produces no significant differences in the inflammatory response in patients undergoing coronary artery bypass grafting with cardiopulmonary bypass.

Haemodynamics and Acid-Base Equilibrium after Cardiac Surgery: Comparison of Rapidly Degradable Hydroxythyl Starch Solutions and Albumin

Background:

Stable haemodynamics is often achieved by administration of colloids after cardiac surgery. We conducted a prospective, randomized, open-label study comparing haemodynamics and acid-base equilibrium after infusion of two rapidly degradable hydroxyethyl starch (HES) solutions or human albumin (HA) to cardiac surgical patients.

Materials and Methods:

45 patients received a predetermined fixed dose of 15 ml kg−1 of either 6% HES (MW 130 kDa, n=15), 6% HES (MW 200 kDa, n=15) or 4% HA (MW 69 kDa, n=15) after on-pump cardiac surgery.

Results:

Left ventricular filling pressures assessed using pulmonary artery catheter responded similarly in all groups. Mean (SD) cardiac index was higher in HES130 [3.5 1 min−1 m−2 (0.7)] and HES200 [3.5 1 min−1 m−2 (0.5)] than in HA [2.8 1 min−1 m−2 (0.6)] group after completion of infusion (P=0.002) but no differences were detected at 2 and 18 hours. Oxygen delivery increased in both HES groups but not in HA group. After cessation of infusion base excess was the most negative in HA group. At 2 hours mean (SD) base excess was higher in HWS130 [0 (1.32)] than in HES200 [-1.32 (2.27)] and HA [-2.3 (1.3)] group (P=0.002, between the groups).

Conclusions:

We conclude that the effect of albumin on cardiac performance is inferior than that of HES130 or HES200 in early postoperative phase after cardiac surgery. HES130 induces no alterations in acid-base equilibrium whereas a negative base excess was observed after HA infusion.

Haemodilution induced by hydroxyethyl starches 130/0.4 is similar in septic and non-septic patients

BACKGROUND

Fluid therapy induces haemodilution related to plasma volume expansion. The aim of our study was to compare haemodilution after a single hydroxyethyl starches (HES) 130/0.4 infusion in two groups of patients, one with and one without sepsis. We hypothesized that a single HES challenge would induce similar sustained haemodilution in both groups.

METHODS

In this prospective preliminary study, patients predicted to require a single further volume-expander infusion were included immediately before receiving 500 ml of 6% HES 130/0.4 over a 15-min period. No additional fluid was administered over the next 8 h. Haematocrit, and serum albumin and protein were determined immediately before HES infusion then after 1, 2, 3, 4, and 8 h.

RESULTS

Twelve patients were included in each group. In both groups, all three haemodilution markers had significantly lower values after 1 h than at baseline. None of the values after 1 and 3 h differed significantly between the two groups. Neither did any of the other study variables show significant differences between the groups with and without sepsis.

CONCLUSION

We found that a starch-based compound was as effective in inducing haemodilution in patients with sepsis as in controls without sepsis, suggesting that HES may remain within the intravascular space even in patients with sepsis. Haemodilution parameters such as haematocrit, serum albumin and serum protein are useful for assessing the duration of plasma volume expansion induced by fluid therapy in critically ill patients.

Volume therapy with colloid solutions preserves intestinal microvascular perfusion in endotoxaemia

Colloid solutions have been suggested to improve microvascular perfusion due to their anti-inflammatory properties. Whether this also applies for the gut, an important immunological organ vulnerable to hypoperfusion is unknown. This study investigated intestinal microcirculation of endotoxaemic rats after volume therapy with colloid solutions such as hydroxyethyl starch (HES) and gelatin or isotonic saline (NaCl). In addition intestinal oxygenation and morphology as well as mesenteric leukocyte-endothelium interaction were quantified. Rats were anaesthetised with urethane and ketamine, mechanically ventilated, and monitored haemodynamically. Normotensive endotoxaemia was induced by a continuous intravenous infusion of Escherichia coli lipopolysaccharide (LPS, 1.5 mg kg(-1) h(-1)). After 1 h of LPS infusion either 6% HES (16 ml kg(-1)), 4% gelatin (16 ml kg(-1)) or 0.9% NaCl (64 ml kg(-1)) were infused for 1 h. Using intravital microscopy, functional capillary density (FCD) and red blood cell velocity (RBCV) were measured in the mucosa of the terminal ileum at baseline and 3 h after volume therapy. In another set of animals, mesenteric leukocyte-endothelium interaction was determined 3 h after volume therapy. In all animals intestinal lactate/pyruvate ratio and intestinal morphology were assessed. Three hours after volume therapy, FCD decreased in NaCl (808 [749/843] cm(-1); median [quartiles] P<0.05 versus baseline) but not in HES (995 [945/1036] cm(-1)) and gelatin (988 [867/1193] cm(-1)) groups. RBCV, lactate/pyruvate ratio and intestinal morphology did not differ among groups. Also mesenteric leukocyte-endothelium interaction was not significantly influenced by either treatment. In conclusion, early volume therapy with HES or gelatin, but not with NaCl, preserved gut microvascular perfusion during endotoxaemia but did not have a significant effect on tissue oxygenation nor morphological appearance in this experimental model. An anti-inflammatory effect of colloid solutions was not seen and fails to explain the changes in intestinal microcirculation.

Determinanten des insensiblen Flüssigkeitsverlustes

Accurate perioperative fluid balance is the basis of a targeted infusion regimen. However, neither the initial status nor perioperative changes of the fluid compartments can be reliably measured in daily routine. In particular, insensible losses are not consistently assessed, so that substitution therapy is generally empirical. The object of this paper is to communicate the scientific data on this topic. Preoperative fasting (10 h) does not per se cause intravascular hypovolemia. In adults, total basal evaporation by way of the skin and airways and of any wounds during major abdominal interventions is usually less than 1 ml/kg/h. An inconstant fluid and protein shift towards the interstitial space perioperatively seems to be associated with hypervolemia, which suggests it should be preventable. The decisive factor in this context seems to be deterioration of the endothelial glycocalyx, whose further patho-physiological impact is currently only partially known. Clinical studies have revealed a link between fluid restriction and improved outcome after major abdominal surgery.

FLUID RESUSCITATION IN SEVERE SEPSIS AND SEPTIC SHOCK

The aim of this study was to investigate whether the type of i.v. fluid administered has an impact on outcome in an animal model of septic shock. The study included 28 anesthetized, invasively monitored, mechanically ventilated female sheep (29.5 +/- 4.0 kg), which received 0.5 g/kg body weight of feces into the abdominal cavity to induce peritonitis. During the surgical operation and 4 h after feces spillage, only Ringer's lactate (RL) was administered in all animals. Thereafter, animals were randomized to receive continuous infusions of RL (n = 7) alone or combined with either 20% albumin (n = 7, volume ratio to RL 1:10) or 6% hydroxyethyl starch (HES) (n = 7, volume ratio to RL 1:1), or gelatin alone (n= 7, no volume limitation). Fluid resuscitation was titrated to maintain pulmonary artery occlusion pressure at baseline levels throughout the experiment. No antibiotics or vasoactive drugs were administered, and animals were monitored until their spontaneous death. Hemodynamic variables were better with HES and albumin than with the other fluids, as reflected by higher stroke volume, cardiac index, and oxygen delivery (all P < 0.05). Hydroxyethyl-starch-treated animals also had lower arterial lactate concentrations (P < 0.01). However, times to develop hypotension and oliguria were similar in all groups. Blood interleukin (IL) 6 concentrations were significantly increased in all groups. The mean survival time was similar in all groups. In this clinically relevant model of prolonged septic shock, albumin and HES solution resulted in higher cardiac output, oxygen delivery, and lower blood lactate levels than gelatin and RL; however, the choice of i.v. fluid did not affect outcome.

Surgical adhesions: a timely update, a great challenge for the future

Damage to the peritoneum during abdominal surgery triggers a cascade of events aimed at repairing the damage. As part of this process, fibrin is deposited, which is the precursor to the formation of an adhesion between 2 damaged peritoneal surfaces. This can have a significant impact on morbidity and even mortality as well as large cost implications. Strategies to reduce adhesion formation include improving surgical techniques, optimizing laparoscopy conditions, using pharmacologic interventions targeted at the inflammatory response and/or fibrin deposition, and using agents that provide a physical barrier to adhesion formation. While these strategies have provided some success, none have yet proved totally successful in abolishing adhesions. Further research to ensure that adhesion prevention is optimal is therefore essential.

Prise en charge anesthésique de l'œsophagectomie: avancées et perspectives

Oesophagectomy is still characterized by a high postoperative mortality and respiratory morbidity. Nevertheless, epidemiological, medical and surgical advances have improved the management of this surgical procedure. The anaesthesiologist influence is present at each level, from the preoperative evaluation to the management of postoperative complications. The preoperative period is improved by the use of assessment scores, the better knowing of respiratory risk factors and of the neoadjuvant therapy adverse effects. The main objective of the operative period is to ensure a rapid weaning procedure and stability of the respiratory and haemodynamic functions, warranting the anastomotic healing. The interest of the association between respiratory rehabilitation and thoracic epidural analgesia is highlighted in the postoperative period. The management of postoperative complications, mainly represented by respiratory failure and anastomotic leakages, requires a multidisciplinary analysis. The potential interest of non-invasive ventilation and of the modulation of postoperative inflammatory response needs further investigation.

Hemodilution Therapy With Hydroxyethyl Starch Solution (130/0.4) in Unilateral Idiopathic Sudden Sensorineural Hearing Loss

OBJECTIVE

Obtain and analyze first data on hydroxyethyl starch (HES 130/0.4) as monotherapy in acute idiopathic sudden sensorineural hearing loss (ISSNHL).

DESIGN

Randomized, double-blind, Phase-II, dose-finding study.

SETTING

Twenty-five ENT centers in Germany, the Czech Republic, Romania, and Austria.

PATIENTS

Two hundred and ten inpatients with first-time ISSNHL of at least 20 dB at two or more frequencies and 95 dB or less at all of the speech frequencies (0.5, 1.0, 2.0, 3.0, and 4.0 kHz) with respect to the other (normal) ear for up to 7 days (d).

INTERVENTION

Infusion of 750 mL/d with 45 (Group H), 30 (Group M), or 15 g/d HES (Group L), or glucose 5% (Group G) acting as "placebo" control during 6 days. MAIN ENDPOINT: Gain in average auditory threshold (in dB) from baseline to Day 7. RESULTS (MEDIANS): Average hearing loss at baseline was 24 dB, and infusions started 2 days after ISSNHL onset. No relevant group difference was observed in hearing gain or adverse treatment events, including pruritus. Half of all patients recovered completely by Day 7. SECONDARY ANALYSIS: In patients who started treatment within 2 days after the onset of symptoms and who had systolic blood'pressure (RRsyst) of less than 140 mm Hg, hearing at Day 90 had improved in all 28 cases under glucose 5%; for those who started treatment later and/or had RRsyst of 140 mm Hg or more, the risk for failing to recover under placebo was 29.2% (7/24). Comparing all 118 (51.9%) of 208 patients at such risk, outcome at Day 7 was markedly better in all HES subgroups than in the G'subgroup'(nH:nM:nL:nG = 32:29:32:24, Kruskal-Wallis, p = 0.0221).

CONCLUSION

All treatment groups were equivalent, including adverse treatment events. The secondary analysis showed that ISSNHL patients at risk for not improving under placebo (i.e., patients who started treatment more than 48 h after ISSNHL onset and/or with elevated RRsyst) recovered markedly better under infusions of HES 130/0.4.

Goal-directed fluid management reduces vasopressor and catecholamine use in cardiac surgery patients

OBJECTIVE

We examined whether guiding therapy by an algorithm based on optimizing the global end-diastolic volume index (GEDVI) reduces the need for vasopressor and inotropic support and helps to shorten ICU stay in cardiac surgery patients.

DESIGN AND SETTING

Single-center clinical study with a historical control group at an university hospital.

PATIENTS

Forty cardiac bypass surgery patients were included prospectively and compared with a control group.

INTERVENTIONS

In the goal-directed therapy (GDT) group hemodynamic management was guided by an algorithm based on GEDVI. Hemodynamic goals were: GEDVI above 640 ml/m2, cardiac index above 2.5 l/min/m2, and mean arterial pressure above 70 mmHg. The control group was treated at the discretion of the attending physician based on central venous pressure, mean arterial pressure, and clinical evaluation.

RESULTS

In the GDT group duration of catecholamine and vasopressor dependence was shorter (187+/-70 vs. 1458+/-197 min), and fewer vasopressors (0.73+/-0.32 vs. 6.67+/-1.21 mg) and catecholamines (0.01+/-0.01 vs. 0.83+/-0.27mg) were administered. They received more colloids (6918+/-242 vs. 5514+/-171ml). Duration of mechanical ventilation (12.6+/-3.6 vs. 15.4+/4.3 h) and time until achieving status of fit for ICU discharge (25+/-13 vs. 33+/-17h) was shorter in the GDT group.

CONCLUSIONS

Guiding therapy by an algorithm based on GEDVI leads to a shortened and reduced need for vasopressors, catecholamines, mechanical ventilation, and ICU therapy in patients undergoing cardiac surgery.

Fluid management of patients undergoing abdominal surgery – more questions than answers *

The 'wet vs. dry' philosophy in patients undergoing abdominal surgery is a subject of substantial debate. It has been suggested that restricting fluid input would significantly reduce complications and improve outcome following abdominal surgery. Keeping the patients dry may be a two-edged sword because the resulting hypovolaemia may result in compromised organ perfusion and poor tissue oxygenation. A review of the literature from 1990 to 2004 revealed that only very few studies on this subject have been published. Unfortunately, most of the 'dry'-supporting studies used fixed amounts of volume instead of a fluid concept adapted to the patients' need ('goal-directed') and there is no generally accepted definition of 'restricted', 'dry' or 'overload'. Not only the amount but also the kind of administered fluid appears to be important. Current evidence indicates that using crystalloids exclusively may cause overloading of the interstitial compartment with considerable negative sequelae, whereas using colloids may improve microperfusion and tissue oxygenation. This review shows that the meagre literature on a restricted volume replacement strategy in abdominal surgery patients cannot clearly support the 'dry' approach. Further well-performed studies are necessary to elucidate the ideal amount and type of fluid replacement and determine how to guide fluid therapy.

Effect of hydroxyethyl starch on vascular leak syndrome and neutrophil accumulation during hypoxia

OBJECTIVE

Several studies have suggested that intravenous hydroxyethyl starch treatment may dampen acute inflammatory responses. It is well documented that limited oxygen delivery to tissues (hypoxia) is common in acute inflammation, and numerous parallels exist between acute responses to hypoxia and to inflammation, including the observation that both are associated with increased vascular leakage and neutrophil infiltration of tissues. Therefore, we compared functional influences of hydroxyethyl starch on normoxic or posthypoxic endothelia.

DESIGN

Laboratory study.

SETTING

University hospital.

SUBJECTS

Cultured human microvascular endothelial cells and mice (C57BL/6/129 svj).

INTERVENTIONS

We measured functional influences of hydroxyethyl starch on normoxic or posthypoxic endothelia.

MEASUREMENTS AND MAIN RESULTS

Studies to assess endothelial barrier function in vitro indicated that the addition of hydroxyethyl starch promotes endothelial barrier in a dose-dependent fashion and hydroxyethyl starch-barrier effects are increased following endothelial hypoxia exposure (human microvascular endothelial cells, 48 hrs, 2% oxygen). Treatment of human microvascular endothelial cells with hydroxyethyl starch resulted in a dose-dependent increase in 157-phosphorylated vasodilator-stimulated phosphoprotein, a protein responsible for controlling the geometry of actin-filaments. Neutrophil adhesion was decreased in the presence of physiologically relevant concentrations of hydroxyethyl starch in vitro, particularly after endothelial hypoxia exposure. Using a murine model of normobaric hypoxia, increases in vascular leakage and pulmonary edema associated with hypoxia exposure (4 hrs at 8% oxygen) were decreased in animals treated with intravenous hydroxyethyl starch. Increases of tissue neutrophil accumulation following hypoxia exposure were dampened in hydroxyethyl starch-treated mice.

CONCLUSIONS

Taken together, these results indicate that hypoxia-induced increases in vascular leakage and acute inflammation are attenuated by hydroxyethyl starch treatment.

DO PLASMA SUBSTITUTES HAVE ADDITIONAL PROPERTIES BEYOND CORRECTING VOLUME DEFICITS?

The best strategy for volume therapy has been the focus of debate and there are still no unique accepted guidelines. There is increasing evidence that some plasma substitutes possess additional effects on organ perfusion, microcirculation, tissue oxygenation, inflammation, endothelial activation, capillary leakage, and tissue edema that are beyond their volume replacing properties. Whether the different plasma substitutes differ with regard this additional effects was reviewed. The additional effects of plasma substitutes have mostly been studied experimentally or in animals, much less results are available in humans. The results are not uniform ranging from beneficial to even detrimental effects of a certain volume replacement strategy. Some important results from the literature are not reflected in the actual recommendations for treating volume deficits in the critically ill: although crystalloids have been shown to have considerable negative effects on microcirculation, organ perfusion, tissue oxygenation, and endothelial integrity, they are still often recommended as first choice volume replacement strategy. In several experimental studies hypertonic solutions have been shown to have various beneficial effects, they have not been, however, translated into humans. In future, the choice of the ideal volume replacement regimen should not only be focused on its volume restoring properties, but additional effects (e.g. on organ perfusion on, tissue oxygenation, inflammation, endothelial activation, capillary leakage) should also be taken into account when treating hypovolemia in the critically ill.