A meta-analysis of randomised controlled trials of intravenous fluid therapy in major elective open abdominal surgery: getting the balance right. Proc Nutr Soc. 2010;69:488-498. [PMID: 20515521 DOI: 10.1017/s0029665110001734]

The physiologic perspective in fluid management in vascular anesthesiology

Vascular surgery patients frequently suffer from atherosclerosis and peripheral arterial occlusive disease generating endothelial dysfunction. Furthermore, ischemia and reperfusion during surgery damage endothelial cells and, especially, the endothelial glycocalix. The damage of the glycocalix promotes an increase in permeability. Not only crystalloids, which freely diffuse between the intravascular and the interstitial compartment, but also colloidal fluids cross from the intravascular space in the interstitial space with the consequence of edema formation. Possible tissue edema may result in an impairment of tissue oxygenation, leading to wound healing disturbances and initiation of inflammatory responses up to tissue apoptosis. Particularly in vascular anesthesia, this possibly means that colloids only should be administered in acute volume resuscitation immediately after unclamping a big vessel for immediate volume restoration. Which colloidal fluid should be administered is still under intense discussion. From a theoretical physiologic point of view, iso-osmolar albumin is the best choice regarding volume effect, antioxidative properties, and protection against destruction of the glycocalix. Nonetheless, albumin experimentally has not lived up to its promise in the clinical setting. Thus, further well-conducted large randomized clinical trials are necessary to ascertain the optimal fluid therapy in vascular surgery patients.

Consensus guidelines for enhanced recovery after gastrectomy: Enhanced Recovery After Surgery (ERAS®) Society recommendations

BACKGROUND

Application of evidence-based perioperative care protocols reduces complication rates, accelerates recovery and shortens hospital stay. Presently, there are no comprehensive guidelines for perioperative care for gastrectomy.

METHODS

An international working group within the Enhanced Recovery After Surgery (ERAS®) Society assembled an evidence-based comprehensive framework for optimal perioperative care for patients undergoing gastrectomy. Data were retrieved from standard databases and personal archives. Evidence and recommendations were classified according to the Grading of Recommendations, Assessment, Development and Evaluation (GRADE) system and were discussed until consensus was reached within the group. The quality of evidence was rated 'high', 'moderate', 'low' or 'very low'. Recommendations were graded as 'strong' or 'weak'.

RESULTS

The available evidence has been summarized and recommendations are given for 25 items, eight of which contain procedure-specific evidence. The quality of evidence varies substantially and further research is needed for many issues to improve the strength of evidence and grade of recommendations.

CONCLUSION

The present evidence-based framework provides comprehensive advice on optimal perioperative care for the patient undergoing gastrectomy and facilitates multi-institutional prospective cohort registries and adequately powered randomized trials for further research.

State-of-the-art fluid management in the operating room

The underlying principles guiding fluid management in any setting are very simple: maintain central euvolemia, and avoid salt and water excess. However, these principles are frequently easier to state than to achieve. Evidence from recent literature suggests that avoidance of fluid excess is important, with excessive crystalloid use leading to perioperative weight gain and an increase in complications. A zero-balance approach aimed at avoiding fluid excess is recommended for all patients. For major surgery, there is a sizeable body of evidence that an individualized goal-directed fluid therapy (GDFT) improves outcomes. However, within an Enhanced Recovery program only a few studies have been published, yet so far GDFT has not achieved the same benefit. Balanced crystalloids are recommended for most patients. The use of colloids remains controversial; however, current evidence suggests they can be beneficial in intraoperative patients with objective evidence of hypovolemia.

Short hospital stays after laparoscopic gastric surgery under an Enhanced Recovery After Surgery (ERAS) pathway: experience at a single center

Introduction

Recently, first reports on benefits from Enhanced Recovery After Surgery (ERAS) pathway in patients undergoing gastric surgery have appeared. It seems that maximal reduction of unfavorable surgery-induced trauma in patients with gastric malignancy via ERAS protocol combined with minimally invasive techniques can improve outcomes.

Objective

The aim of this study was to determine the influence of laparoscopic surgery and ERAS protocol in oncological gastric surgery on early outcomes.

Materials and methods

Prospective analysis involved 28 patients (18 female and 10 male) with gastric malignancy who underwent laparoscopic gastric resection between 2009 and 2013. Gastric tumors (gastrointestinal stromal tumors or adenocarcinoma) were the indication for the surgery. A total of 17 patients underwent laparoscopic local excision, and 11 patients with adenocarcinoma or multiple neuroendocrine tumors underwent laparoscopic D2 total gastrectomy. Perioperative care was based on ERAS principles. Length of hospital stay, postoperative course, perioperative complications, and readmission rates were analyzed.

Results

There was one conversion in the gastrectomy group. All patients were mobilized on the day of surgery. Oral fluids were introduced on day 0 and were well tolerated. Full hospital diet was started on day 2 in all patients, but was well tolerated in only 18 of them. One postoperative complication requiring reoperation was noted. The length of stay after gastrectomy and gastric wedge resection was 4.6 (2–6) and 3.3 (2–6) days, respectively. No readmissions were noted in the entire group.

Conclusions

The implementation of ERAS protocol to clinical practice in combination with laparoscopy in patients with gastric tumors can result in improved postoperative care quality, shortening of hospital stay, and quicker return to normal activity.

Enhanced recovery (ERAS) protocol in patients undergoing laparoscopic total gastrectomy

INTRODUCTION

Laparoscopic technique combined with the ERAS (Enhanced Recovery after Surgery) protocol enables a shorter hospital stay and a lower complication rate. Although it has been widely used in many patients undergoing elective abdominal surgery, especially in patients with colorectal cancer, there are only a few papers describing laparoscopic total gastrectomy and the enhanced recovery protocol in patients with gastric cancer. Minimally invasive gastrectomy is still an uncommon procedure, mostly because of its difficulty.

AIM

To present the preliminary results of treatment of patients with gastric neoplasms who underwent laparoscopic gastrectomy D2 with perioperative care according to ERAS principles.

MATERIAL AND METHODS

Eleven patients (5 male and 6 female, age 52-77 years) underwent laparoscopic D2 gastrectomy with intracorporeal esophagojejunal anastomosis. In all patients the ERAS protocol was implemented. We analyzed operation time, complications and hospital stay. Additionally we focused on operative technique as well as the perioperative care protocol.

RESULTS

The mean duration of the procedure was 245 min. There was 1 conversion due to unclear tumor infiltration. Mean hospital stay was 4.6 days. One postoperative complication (central venous catheter sepsis) was reported. Histological analysis confirmed the tentative diagnosis (R0 resection) in 10/11 patients. There were no readmissions.

CONCLUSIONS

Laparoscopic gastrectomy is a valuable alternative to the classical approach and combined with the ERAS protocol can result in reduced hospital stay. However, due to the small group of patients it is difficult to adequately assess the incidence of early and late complications of the laparoscopic procedures; therefore further research is needed.

Relationship between stroke volume and pulse pressure during blood volume perturbation: a mathematical analysis

Arterial pulse pressure has been widely used as surrogate of stroke volume, for example, in the guidance of fluid therapy. However, recent experimental investigations suggest that arterial pulse pressure is not linearly proportional to stroke volume. However, mechanisms underlying the relation between the two have not been clearly understood. The goal of this study was to elucidate how arterial pulse pressure and stroke volume respond to a perturbation in the left ventricular blood volume based on a systematic mathematical analysis. Both our mathematical analysis and experimental data showed that the relative change in arterial pulse pressure due to a left ventricular blood volume perturbation was consistently smaller than the corresponding relative change in stroke volume, due to the nonlinear left ventricular pressure-volume relation during diastole that reduces the sensitivity of arterial pulse pressure to perturbations in the left ventricular blood volume. Therefore, arterial pulse pressure must be used with care when used as surrogate of stroke volume in guiding fluid therapy.

[Guidelines for enhanced recovery after elective colorectal surgery]

Early recovery after surgery provides patients with all means to counteract or minimize the deleterious effects of surgery. This concept is suitable for a surgical procedure (e.g., colorectal surgery) and comes in the form of a clinical pathway that covers three periods (pre-, intra- and postoperative). The purpose of this Expert panel guideline is firstly to assess the impact of each parameter usually included in the rehabilitation programs on 6 foreseeable consequences of colorectal surgery: surgical stress, postoperative ileus, water and energy imbalance, postoperative immobility, sleep alterations and postoperative complications; secondly, to validate the usefulness of each as criteria of efficiency criteria for success of rehabilitation programs. Two main criteria were selected to evaluate the impact of each parameter: the length of stay and frequency of postoperative complications. Lack of information in the literature forced experts to assess some parameters with criteria (duration of postoperative ileus or quality of analgesia) that mainly surrogate a positive impact for the implementation of an early recovery program. After literature analysis, 19 parameters were identified as potentially interfering with at least one of the foreseeable consequences of colorectal surgery. GRADE® methodology was applied to determine a level of evidence and strength of recommendation. After synthesis of the work of experts using GRADE® method on 19 parameters, 35 recommendations were produced by the organizing committee. The recommendations were submitted and amended by a group of reviewers. After three rounds of Delphi quotes, strong agreement was obtained for 28 recommendations (80%) and weak agreement for seven recommendations. A consensus was reached among anesthesiologists and surgeons on a number of approaches that are likely not sufficiently applied for rehabilitation programs in colorectal surgery such as: preoperative intake of carbohydrates; intraoperative hemodynamic optimization; oral feeding resume before ha24; gum chewing after surgery; patient out of bed and walking at D1. The panel also clarified the value and place of such approaches such as: patient information; preoperative immunonutrition; laparoscopic surgery; antibiotic prophylaxis; prevention of hypothermia; systematic prevention of nausea and vomiting; morphine-sparing analgesic techniques; indications and techniques for bladder catheterization. The panel also confirmed the futility of approaches such as: bowel preparation for colon surgery; maintain of the nasogastric tube; surgical drainage for colonic surgery.

Enhanced recovery for esophagectomy: a systematic review and evidence-based guidelines

OBJECTIVE

This article aims to provide the first systematic review of enhanced recovery after surgery (ERAS) programs for esophagectomy and generate guidelines.

BACKGROUND

ERAS programs use multimodal approaches to reduce complications and accelerate recovery. Although ERAS is well established in colorectal surgery, experience after esophagectomy has been minimal. However, esophagectomy remains an extremely high-risk operation, commonly performed in patients with significant comorbidities. Consequently, ERAS may have a significant role to play in improving outcomes. No guidelines or reviews have been published in esophagectomy.

METHODS

We undertook a systematic review of the PubMed, EMBASE, and the Cochrane databases in July 2012. The literature was searched for descriptions of ERAS in esophagectomy. Components of successful ERAS programs were determined, and when not directly available for esophagectomy, extrapolation from related evidence was made. Graded recommendations for each component were then generated.

RESULTS

Six retrospective studies have assessed ERAS for esophagectomy, demonstrating favorable morbidity, mortality, and length of stay. Methodological quality is, however, low. Overall, there is little direct evidence for components of ERAS, with much derived from nonesophageal thoracoabdominal surgery.

CONCLUSIONS

ERAS in principle seems logical and safe for esophagectomy. However, the underlying evidence is poor and lacking. Despite this, a number of recommendations for practice and research can be made.

Perioperative anemia management in colorectal cancer patients: A pragmatic approach

Anemia, usually due to iron deficiency, is highly prevalent among patients with colorectal cancer. Inflammatory cytokines lead to iron restricted erythropoiesis further decreasing iron availability and impairing iron utilization. Preoperative anemia predicts for decreased survival. Allogeneic blood transfusion is widely used to correct anemia and is associated with poorer surgical outcomes, increased post-operative nosocomial infections, longer hospital stays, increased rates of cancer recurrence and perioperative venous thromboembolism. Infections are more likely to occur in those with low preoperative serum ferritin level compared to those with normal levels. A multidisciplinary, multimodal, individualized strategy, collectively termed Patient Blood Management, minimizes or eliminates allogeneic blood transfusion. This includes restrictive transfusion policy, thromboprophylaxis and anemia management to improve outcomes. Normalization of preoperative hemoglobin levels is a World Health Organization recommendation. Iron repletion should be routinely ordered when indicated. Oral iron is poorly tolerated with low adherence based on published evidence. Intravenous iron is safe and effective but is frequently avoided due to misinformation and misinterpretation concerning the incidence and clinical nature of minor infusion reactions. Serious adverse events with intravenous iron are extremely rare. Newer formulations allow complete replacement dosing in 15-60 min markedly facilitating care. Erythropoiesis stimulating agents may improve response rates. A multidisciplinary, multimodal, individualized strategy, collectively termed Patient Blood Management used to minimize or eliminate allogeneic blood transfusion is indicated to improve outcomes.

Perioperative fluid restriction in major abdominal surgery: systematic review and meta-analysis of randomized, clinical trials

BACKGROUND

Fluid management is a fundamental component of surgical care. Recently, there has been considerable interest in perioperative fluid restriction as a method of facilitating recovery following elective major surgery. A number of randomized trials have addressed the issue in various surgical specialities, and a recent meta-analysis proposed uniform definitions regarding fluid amount as well as examining fluid restriction in patients undergoing colonic resection.

METHODS

Medline, Embase, trial registries, conference proceedings, and article reference lists were searched to identify randomized, controlled trials of perioperative fluid restriction versus "standard" perioperative fluid management, as per definitions formulated previously. All of the studies involved patients undergoing colonic resection. The primary outcome measure was postoperative morbidity. Secondary endpoints included mortality, renal failure, time to first flatus, and length of hospital stay. A random effects model was applied.

RESULTS

Seven randomized, controlled trials with a total of 856 patients investigating standard versus restrictive fluid regimes, as denoted by the definitions, were included. Perioperative fluid restriction had no effect on the risk of postoperative complications (OR 0.49 (95 % confidence interval (CI) 0.2-1.18; P = 0.101). There was no detectable effect on death and fluid restriction did not reduce hospital stay (Pooled weighted mean difference -0.25; 95 % CI 0.72-0.21; P = 0.29).

CONCLUSIONS

Perioperative fluid restriction does not significantly reduce the risk of complications following major abdominal surgery. Furthermore, it does not appear to reduce length of hospital stay.

Systematic review and meta-analysis of oesophageal Doppler-guided fluid management in colorectal surgery

BACKGROUND

Oesophageal Doppler monitor (ODM)-guided fluid therapy has been recommended for routine use in patients undergoing colorectal surgery. However, recent trials have suggested either equivalent or inferior results for patients randomized to ODM-guided fluid management, especially when compared with fluid restriction or within the context of optimized perioperative care. Hence, an updated systematic review and meta-analysis was conducted.

METHODS

A systematic review and meta-analysis was conducted of all randomized trials exploring ODM-guided fluid management in major colorectal surgery with the endpoints total complications and length of hospital stay (LOS). Subset analyses were planned a priori specifically to investigate the role of the ODM in the context of fluid restriction or optimized perioperative care.

RESULTS

Six high-quality trials comprising a total of 691 patients were included in the final analysis. ODM-guided fluid therapy did not influence the incidence of complications (odds ratio 0·74, 95 per cent confidence interval (c.i.) 0·50 to 1·11; P = 0·15), with moderate heterogeneity in the results (I(2)  = 33 per cent; P = 0·19). There was no difference in mean LOS between patients receiving ODM-guided fluid therapy and controls: mean difference -0·88 (95 per cent c.i. -2·89 to 1·13) days (P = 0·39). There was no difference in complications or LOS when ODM-guided fluid therapy was compared with fluid restriction or used within an otherwise optimized perioperative environment.

CONCLUSION

ODM-guided fluid therapy did not influence LOS or complications in patients undergoing colorectal surgery. Results favouring the ODM were seen only in early studies, whereas newer trials did not show any benefit from such monitoring.

Fluid homeostasis in the neonate

The physiology of the neonate is ideally suited to the transition to extrauterine life followed by a period of rapid growth and development. Intravenous fluids and electrolytes should be prescribed with care in the neonate. Sodium and water requirements in the first few days of life are low and should be increased after the postnatal diuresis. Expansion of the extracellular fluid volume prior to the postnatal diuresis is associated with poor outcomes, particularly in preterm infants. Newborn infants are prone to hypoglycemia and require a source of intravenous glucose if enteral feeds are withheld. Anemia is common, and untreated is associated with poor outcomes. Liberal versus restrictive transfusion practices are controversial, but liberal transfusion practices (accompanied by measures to minimize donor exposure) may be associated with improved long-term outcomes. Intravenous crystalloids are as effective as albumin to treat hypotension, and semi-synthetic colloids cannot be recommended at this time. Inotropes should be used to treat hypotension unresponsive to intravenous fluid, ideally guided by assessment of perfusion rather than blood pressure alone. Noninvasive methods of assessing cardiac output have been validated in neonates. More studies are required to guide fluid management in neonates, particularly in those with sepsis or undergoing surgery. A balanced salt solution such as Hartmann's or Plasmalyte should be used to replace losses during surgery (and blood or coagulation factors as indicated). Excessive fluid administration during surgery should be avoided.

The pathophysiology of fluid and electrolyte balance in the older adult surgical patient

BACKGROUND & AIMS

Age-related physiological changes predispose even the healthy older adult to fluid and electrolyte abnormalities which can cause morbidity and mortality. The aim of this narrative review is to highlight key aspects of age-related pathophysiological changes that affect fluid and electrolyte balance in older adults and underpin their importance in the perioperative period.

METHODS

The Web of Science, MEDLINE, PubMed and Google Scholar databases were searched using key terms for relevant studies published in English on fluid balance in older adults during the 15 years preceding June 2013. Randomised controlled trials and large cohort studies were sought; other studies were used when these were not available. The bibliographies of extracted papers were also searched for relevant articles.

RESULTS

Older adults are susceptible to dehydration and electrolyte abnormalities, with causes ranging from physical disability restricting access to fluid intake to iatrogenic causes including polypharmacy and unmonitored diuretic usage. Renal senescence, as well as physical and mental decline, increase this susceptibility. Older adults are also predisposed to water retention and related electrolyte abnormalities, exacerbated at times of physiological stress. Positive fluid balance has been shown to be an independent risk factor for morbidity and mortality in critically ill patients with acute kidney injury.

CONCLUSIONS

Age-related pathophysiological changes in the handling of fluid and electrolytes make older adults undergoing surgery a high-risk group and an understanding of these changes will enable better management of fluid and electrolyte therapy in the older adult.

Dose and type of crystalloid fluid therapy in adult hospitalized patients

OBJECTIVE

In this narrative review, an overview is given of the pros and cons of various crystalloid fluids used for infusion during initial resuscitation or maintenance phases in adult hospitalized patients. Special emphasis is given on dose, composition of fluids, presence of buffers (in balanced solutions) and electrolytes, according to recent literature. We also review the use of hypertonic solutions.

METHODS

We extracted relevant clinical literature in English specifically examining patient-oriented outcomes related to fluid volume and type.

RESULTS

A restrictive fluid therapy prevents complications seen with liberal, large-volume therapy, even though restrictive fluid loading with crystalloids may not demonstrate large hemodynamic effects in surgical or septic patients. Hypertonic solutions may serve the purpose of small volume resuscitation but carry the disadvantage of hypernatremia. Hypotonic solutions are contraindicated in (impending) cerebral edema, whereas hypertonic solutions are probably more helpful in ameliorating than in preventing this condition and improving outcome. Balanced solutions offer a better approach for plasma composition than unbalanced ones, and the evidence for benefits in patient morbidity and mortality is increasing, particularly by helping to prevent acute kidney injury.

CONCLUSIONS

Isotonic and hypertonic crystalloid fluids are the fluids of choice for resuscitation from hypovolemia and shock. The evidence that balanced solutions are superior to unbalanced ones is increasing. Hypertonic saline is effective in mannitol-refractory intracranial hypertension, whereas hypotonic solutions are contraindicated in this condition.

Changes in body composition, hematologic parameters, and serum biochemistry after rapid intravenous infusion or oral intake of 2 liters of 0.9% saline solution in young healthy volunteers: randomized crossover study

BACKGROUND

The perioperative infusion of 2 L of saline is associated with weight gain and decreased serum albumin and hematocrit. We hypothesized that these parameters would respond differently to oral administration and intravenous infusion of saline solution.

METHODS

This was a crossover study that included 10 healthy young men (ages 18-26 years). At two times, 8 weeks apart, the participants were randomized to receive 2 L of 0.9% saline over 1 h by intravenous (IV) administration to a forearm vein or by oral intake. The participants were weighed and body masses were calculated. Bioelectrical impedance analysis was performed with a single-frequency device using tetrapolar distal limb electrodes. Blood samples were collected 1 h after the administration period for laboratory assays: hematocrit, hemoglobin, blood glucose, serum electrolytes, albumin, creatinine, osmolality.

RESULTS

There was an increase in body weight (p<0.01), total body water (p<0.01), and lean body mass (p<0.01) after the experiment in both groups, with no difference between them. The volume of urine output was similar in the two experiments. The hemoglobin (oral group from 14.4±0.8 g/dl to 13.8±0.8 g/dl; IV group from 14.4±0.6 g/dl to 12.6±0.6 g/dl) and hematocrit (oral group from 43.2±1.8% to 43.2±2.8%; IV group from 43.6±2.2% to 40.0±2.6%) significantly decreased (p<0.01) with IV saline. Serum albumin remained stable after oral intake but significantly decreased (p=0.04) after IV infusion.

CONCLUSIONS

Oral intake of 2 L of 0.9% saline results in minimal variations in serum albumin, hemoglobin, and hematocrit when compared to IV infusion of the same volume.

Intrathecal analgesia and restrictive perioperative fluid management within enhanced recovery pathway: hemodynamic implications

BACKGROUND

Intrathecal analgesia and avoidance of perioperative fluid overload are key items within enhanced recovery pathways. Potential side effects include hypotension and renal dysfunction.

STUDY DESIGN

From January 2010 until May 2010, all patients undergoing colorectal surgery within enhanced recovery pathways were included in this retrospective cohort study and were analyzed by intrathecal analgesia (IT) vs none (noIT). Primary outcomes measures were systolic and diastolic blood pressure, mean arterial pressure, and heart rate for 48 hours after surgery. Renal function was assessed by urine output and creatinine values.

RESULTS

One hundred and sixty-three consecutive colorectal patients (127 IT and 36 noIT) were included in the analysis. Both patient groups showed low blood pressure values within the first 4 to 12 hours and a steady increase thereafter before return to baseline values after about 24 hours. Systolic and diastolic blood pressure and mean arterial pressure were significantly lower until 16 hours after surgery in patients having IT compared with the noIT group. Low urine output (<0.5 mL/kg/h) was reported in 11% vs 29% (IT vs noIT; p = 0.010) intraoperatively, 20% vs 11% (p = 0.387), 33% vs 22% (p = 0.304), and 31% vs 21% (p = 0.478) for postanesthesia care unit and postoperative days 1 and 2, respectively. Only 3 of 127 (2.4%) IT and 1 of 36 (2.8%) noIT patients had a transitory creatinine increase >50%; no patients required dialysis.

CONCLUSIONS

Postoperative hypotension affects approximately 10% of patients within an enhanced recovery pathway and is slightly more pronounced in patients with IT. Hemodynamic depression persists for <20 hours after surgery; it has no measurable negative impact and therefore cannot justify detrimental postoperative fluid overload.

The challenge of intra-abdominal sepsis

An overview of intra-abdominal sepsis is necessary at this time with new experimental studies, scoring systems and audits on management outcomes. The understanding of the pathophysiology of the peritoneum in the manifestation of surgical sepsis and the knowledge of the source of pathogenic organisms which reach the peritoneal cavity are crucial in the prevention of intra-abdominal infection. Inter-individual variation in the pattern of mediator release and of end-organ responsiveness may play a significant role in determining the initial physiological response to major sepsis and this in turn may be a key determinant of outcome. The ability to identify the presence of peritoneal inflammation probably has the greatest influence on the final surgical decision. The prevention of the progression of sepsis is by early goal-directed therapy and source control. Recent advances in interventional techniques for peritonitis have significantly reduced the morbidity and mortality of physiologically severe complicated abdominal infection. In the critically ill patients there is some evidence that the prevention of gut mucosal acidosis improves outcome. The aim of this review is to ascertain why intra-abdominal sepsis remains a major clinical challenge and how a better understanding of the pathophysiology may enable its prevention and better management.

METHOD

Electronic searches of the medline (PubMed) database, Cochrane library, and science citation index were performed to identify original published studies on intra-abdominal sepsis and the current management. Relevant articles were searched from relevant chapters in specialized texts and all included.

Acid-base and electrolyte balance following administration of three crystalloid solutions in dogs undergoing elective orthopaedic surgery

OBJECTIVE

To compare acid-base balance and incidence of hyperchloraemic metabolic acidosis following administration of three crystalloid solutions to dogs undergoing anaesthesia for orthopaedic surgery.

STUDY DESIGN

Prospective, randomised, clinical study.

ANIMALS

Sixty dogs.

METHODS

During a non-standardised anaesthetic, 0.9% saline (S), Hartmann's solution (H) or a polyionic glucose-free maintenance solution (M) was administered IV at 10 mL kg(-1)  hour(-1) . Venous blood pH, PCO2 , PCV, total protein, urea, sodium, potassium and chloride concentrations were measured at induction of anaesthesia (T0) and after 2 hours of fluid therapy (T2). Base excess (BE), bicarbonate, corrected chloride concentration (corrCl), osmolality, change in plasma volume (PV) and strong ion gap (SIG) were calculated. Changes in variables within groups (1-sample Student's t-test/Wilcoxon signed rank test) and between groups (1-way anova/Kruskal-Wallis) were assessed. Data are presented as median (interquartile range). Significance was set at p < 0.05.

RESULTS

No significant differences existed between groups for pH, PCO2 , PCV, total protein, urea, potassium, corrCl, PV and SIG. Potassium significantly increased in all groups. Significant differences existed between groups S and M for BE, sodium, chloride, bicarbonate and osmolality, and between groups H and M for sodium and osmolality. Chloride concentration significantly changed from 116 (114-117) to 117 (116-119) mmol L(-1) in group S, 116 (115-118) to 115 (113-117) mmol L(-1) in group H and 116 (115-118) to 114 (113-118)  mmol L(-1) in group M. In groups H and M, sodium and osmolality decreased, and BE and bicarbonate concentration increased significantly. Plasma volume increased by 28 (14-44)%, 25 (5-40)% and 24 (13-33)% in groups S, H and M, respectively.

CONCLUSION AND CLINICAL RELEVANCE

Hyperchloraemic metabolic acidosis did not develop after intraoperative 0.9% saline, Hartmann's solution or maintenance solution at 10 mL kg(-1)  hour(-1) for 2 hours in dogs undergoing elective orthopaedic surgery. Bicarbonate and BE increased after Hartmann's and maintenance solutions. Increases in potassium concentration were unexplained.

Development and feasibility study of an algorithm for intraoperative goaldirected haemodynamic management in noncardiac surgery

This study developed an evidence-based, goal-directed haemodynamic management algorithm to standardize intraoperative haemodynamic therapy. A systematic literature search identified three haemodynamic management goals: stroke volume optimization by fluid therapy; maintenance of a target mean arterial pressure by vasopressor therapy; maintenance of a target cardiac index≥2.5 l/min per m2 by inotropic therapy. The algorithm was adapted to international standards and consensus was reached through a modified Delphi method at international meetings. Implementation of the algorithm into routine intraoperative management in noncardiac surgery was shown to be feasible. Compared with conventional haemodynamic management, use of the algorithm significantly reduced length of hospital stay, requirement for ventilation and incidence of prolonged hospital stay, thereby resulting in reduced hospital costs.

Perioperative fluid administration: historical highlights and implications for practice

Perioperative fluid administration is an important aspect of surgical care but is often poorly understood. Surgeons have historically made a considerable contribution to the evidence base governing current practice. This review provides an overview of the history of perioperative fluid therapy and its relevance to modern practice.Intravenous fluids (IVF) first gained therapeutic importance in the treatment of cholera in the 1830s. From the 1880s, IVF began to be administered perioperatively to compensate for the "injurious" effects of anaesthesia. Clinical improvements were consequently noted, though the adverse effects of saline were observed. The work of Ringer, Hartmann, and others emphasized the importance of the composition of IVF and laid the foundations for the balanced solutions in use today.The intravenous "drip" was introduced by Rudolph Matas in 1924. As the metabolic response to injury was increasingly investigated in the 1940s and 1950s, the cause of post-operative oliguria was debated widely with the most prominent surgeons being Moore and Shires. These differences in opinion, coupled with reports of injured soldiers from the Korean War receiving large IVF infusions and surviving, dictated the surgical practice of liberal IVF administration until very recently.Newer work in fluid therapy has explored the concept of fluid restriction. Shoemaker and colleagues also pioneered the concept of fluid administration to achieve supranormal indices of cardiorespiratory function, which has led to the advent of goal-directed fluid therapy. Alongside the development of balanced solutions, the renewed focus on perioperative fluid therapy has led to IVF administration being guided by physiological principles with a new consideration of the lessons gleaned from history.

Randomized clinical trial of goal-directed fluid therapy within an enhanced recovery protocol for elective colectomy

BACKGROUND

Goal-directed fluid therapy (GDFT) has been compared with liberal fluid administration in non-optimized perioperative settings. It is not known whether GDFT is of value within an enhanced recovery protocol incorporating fluid restriction. This study evaluated GDFT under these circumstances in patients undergoing elective colectomy.

METHODS

Patients undergoing elective laparoscopic or open colectomy within an established enhanced recovery protocol (including fluid restriction) were randomized to GDFT or no GDFT. Bowel preparation was permitted for left colonic operations at the surgeon's discretion. Exclusion criteria included rectal tumours and stoma formation. The primary outcome was a patient-reported surgical recovery score (SRS). Secondary endpoints included clinical outcomes and physiological measures of recovery.

RESULTS

Eighty-five patients were randomized, and there were 37 patients in each group for analysis. Nine patients in the GDFT and four in the fluid restriction group received oral bowel preparation for either anterior resection (12) or subtotal colectomy (1). Patients in the GDFT group received more colloid during surgery (mean 591 versus 297 ml; P = 0·012) and had superior cardiac indices (mean corrected flow time 374 versus 355 ms; P = 0·018). However, no differences were observed between the GDFT and fluid restriction groups with regard to surgical recovery (mean SRS after 7 days 47 versus 46 respectively; P = 0·853), other secondary outcomes (mean aldosterone/renin ratio 9 versus 8; P = 0·898), total postoperative fluid (median 3750 versus 2400 ml; P = 0·604), length of hospital stay (median 6 versus 5 days; P = 0·570) or number of patients with complications (26 versus 27; P = 1·000).

CONCLUSION

GDFT did not provide clinical benefit in patients undergoing elective colectomy within a protocol incorporating fluid restriction.

REGISTRATION NUMBER

NCT00911391 (http://www.clinicaltrials.gov).

Guidelines for perioperative care in elective colonic surgery: Enhanced Recovery After Surgery (ERAS®) Society recommendations

BACKGROUND

This review aims to present a consensus for optimal perioperative care in colonic surgery and to provide graded recommendations for items for an evidenced-based enhanced perioperative protocol.

METHODS

Studies were selected with particular attention paid to meta-analyses, randomised controlled trials and large prospective cohorts. For each item of the perioperative treatment pathway, available English-language literature was examined, reviewed and graded. A consensus recommendation was reached after critical appraisal of the literature by the group.

RESULTS

For most of the protocol items, recommendations are based on good-quality trials or meta-analyses of good-quality trials (quality of evidence and recommendations according to the GRADE system).

CONCLUSIONS

Based on the evidence available for each item of the multimodal perioperative-care pathway, the Enhanced Recovery After Surgery (ERAS) Society, International Association for Surgical Metabolism and Nutrition (IASMEN) and European Society for Clinical Nutrition and Metabolism (ESPEN) present a comprehensive evidence-based consensus review of perioperative care for colonic surgery.

Which goal for fluid therapy during colorectal surgery is followed by the best outcome: near-maximal stroke volume or zero fluid balance?

BACKGROUND

We aimed to investigate whether fluid therapy with a goal of near-maximal stroke volume (SV) guided by oesophageal Doppler (ED) monitoring result in a better outcome than that with a goal of maintaining bodyweight (BW) and zero fluid balance in patients undergoing colorectal surgery.

METHODS

In a double-blinded clinical multicentre trial, 150 patients undergoing elective colorectal surgery were randomized to receive fluid therapy after either the goal of near-maximal SV guided by ED (Doppler, D group) or the goal of zero balance and normal BW (Zero balance, Z group). Stratification for laparoscopic and open surgery was performed. The postoperative fluid therapy was similar in the two groups. The primary endpoint was postoperative complications defined and divided into subgroups by protocol. Analysis was performed by intention-to-treat. The follow-up was 30 days. The trial had 85% power to show a difference between the groups.

RESULTS

The number of patients undergoing laparoscopic or open surgery and the patient characteristics were similar between the groups. No significant differences between the groups were found for overall, major, minor, cardiopulmonary, or tissue-healing complications (P-values: 0.79; 0.62; 0.97; 0.48; and 0.48, respectively). One patient died in each group. No significant difference was found for the length of hospital stay [median (range) Z: 5.00 (1-61) vs D: 5.00 (2-41); P=0.206].

CONCLUSIONS

Goal-directed fluid therapy to near-maximal SV guided by ED adds no extra value to the fluid therapy using zero balance and normal BW in patients undergoing elective colorectal surgery.

NHS Diabetes guideline for the perioperative management of the adult patient with diabetes

These Joint British Diabetes Societies guidelines, commissioned by NHS Diabetes, for the perioperative management of the adult patient undergoing surgery are available in full in the Supporting Information. This document goes through the seven stages of the patient journey when having surgery. These are: primary care referral; surgical outpatients; preoperative assessment; hospital admission; surgery; post-operative care; discharge. Each stage is given its own considerations, outlining the roles and responsibilities of each group of healthcare professionals. The evidence base for the recommendations made at each stage, discussion of controversial areas and references are provided in the report. This document has two key recommendations. Firstly, that the management of the elective adult surgery patients should be with modification to their usual diabetes treatment if the fasting is minimized because the routine use of a variable rate intravenous insulin infusion is not recommended. Secondly, that poor preoperative glycaemic control leads to post-outcomes and thus, where appropriate, needs to be addressed prior to referral for surgery.

Serum brain naturietic peptide measurements reflect fluid balance after pancreatectomy

BACKGROUND

Overaggressive fluid resuscitation in elderly patients requiring pancreatectomy can delay recovery and increase morbidity. Despite advancements, no accurate and reproducible methods exist to evaluate effective intravascular volume status in the postoperative setting. We hypothesized that sequential measurement of currently available serum proteins will indicate fluid balance.

STUDY DESIGN

Clinicopathologic (n = 44) and echocardiogram (echo) data (n = 18) were collected on patients receiving pancreatectomy or diagnostic laparoscopy (n = 5). Measured fluid balance, serum BUN, creatinine (CR), and brain natriuretic peptide (BNP) levels were recorded on postoperative days (POD) 1 to 7 (only POD1 for diagnostic laparoscopy). ANOVA and bivariate random effect models examined the correlation between BNP and BUN/CR and fluid balance. Linear mixed-effect models examined the correlation between factors associated with vascular stiffness and BNP, BUN/CR, and fluid balance.

RESULTS

On POD1 after diagnostic laparoscopy, the fluid balance was positive by 3,265 mL and was accompanied by a >300-point increase in BNP (p = 0.0083). After pancreatectomy, a similar increase in BNP (250 pg/mL) and fluid balance (4,492 mL) on POD1 was observed. During the return to euvolemia, the change in serum BNP levels correlated with fluid balance changes during POD 1 to 3 (p = 0.039), and BUN/CR levels correlated with fluid balance during POD 4 to 7. Patients with risk factors associated with cardiovascular stiffness or echo evidence of poor compliance experienced higher BNP during the postoperative period.

CONCLUSIONS

Fluid loading at surgery is accompanied by an increase in serum BNP, and return to a balanced fluid state after pancreatectomy is paralleled by changes in BNP and BUN/CR levels.

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.

Randomized clinical trial of fluid restriction in colorectal surgery

BACKGROUND

Perioperative fluid therapy can influence postoperative hospital stay and complications after elective colorectal surgery. This trial was designed to examine whether an extremely restricted perioperative fluid protocol would reduce hospital stay beyond the existing fast-track hospital time of 7 days after surgery.

METHODS

Patients were randomized to restricted or standard perioperative intravenous fluid regimens in a single-centre trial. Randomization was stratified for colonic, rectal, open and laparoscopic surgery. Patients were all treated within a fast-track protocol (careful preoperative preparation, optimal analgesia, early oral nutrition and early mobilization). The primary endpoint was length of postoperative hospital stay. The secondary endpoint was complications within 30 days.

RESULTS

Seventy-nine patients were randomized to restricted and 82 to standard fluid therapy. Patients in the restricted group received a median of 3050 ml fluid on the day of surgery compared with 5775 ml in the standard group (P < 0·001). There was no difference between groups in primary hospital stay (median 6·0 days in both groups; P = 0·194) or stay including readmission (median 6·0 days in both groups; P = 0·158). The proportion of patients with complications was significantly lower in the restricted group (31 of 79 versus 47 of 82; P = 0·027). Vasopressors were more often required in the restricted group (97 versus 80 per cent; P < 0·001).

CONCLUSION

Restricted perioperative intravenous fluid administration does not reduce length of stay in a fast-track protocol.

Fluids and gastrointestinal function

PURPOSE OF REVIEW

To highlight recent developments relating perioperative fluid therapy to gastrointestinal function by reviewing clinically pertinent English language articles mainly from January 2010 to March 2011.

RECENT FINDINGS

The control of fluid and electrolyte balance involves multiple processes in which the gastrointestinal tract plays an integral role. Diseases affecting the gastrointestinal tract commonly cause fluid and electrolyte disturbance. Similarly, intravenous fluid therapy in the perioperative period can affect gastrointestinal function and have a bearing on postoperative outcome. Striking a balance, in terms of both fluid composition and volume, is likely to reduce the morbidity associated with interstitial edema, a frequently observed occurrence with contemporary perioperative fluid regimens. This balance may be best achieved using individualized and goal-directed approaches to fluid therapy, in order to provide fluid when it is needed and in the correct quantities.

SUMMARY

In planning strategies of fluid therapy, the possibility of adverse effects on the gastrointestinal tract should be considered, as this is likely to have an impact on fluid and electrolyte balance and postoperative outcome.

Prediction, prevention and management of postresection liver failure

Background

Postresection liver failure (PLF) is the major cause of death following liver resection. However, there is no unified definition, the pathophysiology is understood poorly and there are few controlled trials to optimize its management. The aim of this review article is to present strategies to predict, prevent and manage PLF.

Methods

The Web of Science, MEDLINE, PubMed, Google Scholar and Cochrane Library databases were searched for studies using the terms ‘liver resection’, ‘partial hepatectomy’, ‘liver dysfunction’ and ‘liver failure’ for relevant studies from the 15 years preceding May 2011. Key papers published more than 15 years ago were included if more recent data were not available. Papers published in languages other than English were excluded.

Results

The incidence of PLF ranges from 0 to 13 per cent. The absence of a unified definition prevents direct comparison between studies. The major risk factors are the extent of resection and the presence of underlying parenchymal disease. Small-for-size syndrome, sepsis and ischaemia–reperfusion injury are key mechanisms in the pathophysiology of PLF. Jaundice is the most sensitive predictor of outcome. An evidence-based approach to the prevention and management of PLF is presented.

Conclusion

PLF is the major cause of morbidity and mortality after liver resection. There is a need for a unified definition and improved strategies to treat it.

Innovations in treating aortic diseases: the abdominal aorta

Patients with an abdominal aortic aneurysm (AAA) could benefit from earlier diagnosis to improve long-term outcomes. Candidate serum biomarkers for earlier AAA diagnosis include D-dimer, fibrinogen, low-density lipoprotein, high-density lipoprotein, lipoprotein(a), and the proteolytic enzymes known as matrix metalloproteinases. Furthermore, biomarkers such as brain natriuretic peptide significantly stratify perioperative risk in AAA repair. Statins significantly improve outcomes after AAA repair. They may also significantly slow AAA growth to allow pharmacologic arrest of AAA development. Recent trials have focused attention on fluid management for AAA repair. Although restrictive fluid management may significantly improve clinical outcomes, current evidence does not clearly support crystalloid or colloid for AAA repair. There may be an increased risk of renal dysfunction associated with hetastarch therapy. Endovascular repair has revolutionized the clinical management of AAAs. Recent trials have shown its significant outcome advantages. Furthermore, it is also applicable in high-risk operative cohorts and, in the future, may be suited for earlier AAA repair. This technology continues to advance with the development of branched and fenestrated grafts as well as total percutaneous endovascular AAA repair. Regardless of these advances, the clinical management of endoleaks will remain a major clinical focus. Taken together, these advances in the management of AAAs likely will significantly influence future clinical approaches to this challenging patient cohort.