Meta-analysis of standard, restrictive and supplemental fluid administration in colorectal surgery

A meta-analysis of randomised controlled trials of intravenous fluid therapy in major elective open abdominal surgery: getting the balance right

The terminology used for describing intervention groups in randomised controlled trials (RCT) on the effect of intravenous fluid on outcome in abdominal surgery has been imprecise, and the lack of standardised definitions of the terms 'standard', 'restricted' and 'liberal' has led to some confusion and difficulty in interpreting the literature. The aims of this paper were to clarify these definitions and to use them to perform a meta-analysis of nine RCT on primarily crystalloid-based peri-operative intravenous fluid therapy in 801 patients undergoing elective open abdominal surgery. Patients who received more or less fluids than those who received a 'balanced' amount were considered to be in a state of 'fluid imbalance'. When 'restricted' fluid regimens were compared with 'standard or liberal' fluid regimens, there was no difference in post-operative complication rates (risk ratio 0.83 (95% CI 0.49, 1.39, P = 0.47) [corrected] or length of hospital stay (weighted mean difference (WMD) - 1.77 (95% CI - 4.36, 0.81) d, P = 0.18). However, when the fluid regimens were reclassified and patients were grouped into those who were managed in a state of fluid 'balance' or 'imbalance', the former group had significantly fewer complications (risk ratio 0·59 (95% CI 0·44, 0·81), P=0·0008) and a shorter length of stay (WMD -3·44 (95% CI -6·33, -0·54) d, P=0·02) than the latter. Using imprecise terminology, there was no apparent difference between the effects of fluid-restricted and standard or liberal fluid regimens on outcome in patients undergoing elective open abdominal surgery. However, patients managed in a state of fluid balance fared better than those managed in a state of fluid imbalance.

[Non-cardiac surgery in patients with cardiac disease]

BACKGROUND

Patients with cardiac disease have a higher incidence of cardiovascular events after non-cardiac surgery than those without such disease. This paper provides an overview of perioperative examinations and treatment.

MATERIAL AND METHODS

Own experience and systematic literature search through work with European guidelines constitute the basis for recommendations given in this article.

RESULTS

Beta-blockers should not be discontinued before surgery. High-risk patients may benefit from beta-blockers administered before major non-cardiac surgery. Slow dose titration is recommended. Echocardiography should be performed before preoperative beta-blockade to exclude latent heart failure. Statins should be considered before elective surgery and coronary intervention (stenting or surgery) before high-risk surgery. Otherwise, interventions should be evaluated irrespective of planned non-cardiac surgery. Patients with unstable coronary syndrome should only undergo non-cardiac surgery on vital indications. Neuraxial techniques are optimal for postoperative pain relief and thus for postoperative mobilization. Thromboprophylaxis is important, but increases the risk of epidural haematoma and requires systematic follow-up with respect to diagnostics and treatment.

INTERPRETATION

Little evidence supports the use of different anaesthetic methods in cardiac patients that undergo non-cardiac surgery than in other patients. Stable circulation, sufficient oxygenation, good pain relief, thromboprophylaxis, enteral nutrition and early mobilization are important factors for improving the perioperative course. Close cooperation between anaesthesiologist, surgeon and cardiologist improves logistics and treatment.

The enhanced recovery after surgery (ERAS) pathway for patients undergoing major elective open colorectal surgery: a meta-analysis of randomized controlled trials

BACKGROUND & AIMS

The aim of the Enhanced Recovery After Surgery (ERAS) pathway is to attenuate the stress response to surgery and enable rapid recovery. The objective of this meta-analysis was to study the differences in outcomes in patients undergoing major elective open colorectal surgery within an ERAS pathway and those treated with conventional perioperative care.

METHODS

Medline, Embase and Cochrane database searches were performed for relevant studies published between January 1966 and November 2009. All randomized controlled trials comparing ERAS with conventional perioperative care were selected. The outcome measures studied were length of hospital stay, complication rates, readmission rates and mortality.

RESULTS

Six randomized controlled trials with 452 patients were included. The number of individual ERAS elements used ranged from 4 to 12, with a mean of 9. The length of hospital stay [weighted mean difference (95% confidence interval): -2.55 (-3.24, -1.85)] and complication rates [relative risk (95% confidence interval): 0.53 (0.44, 0.64)] were significantly reduced in the enhanced recovery group. There was no statistically significant difference in readmission and mortality rates.

CONCLUSION

ERAS pathways appear to reduce the length of stay and complication rates after major elective open colorectal surgery without compromising patient safety.

Fluids in septic shock: too much of a good thing?

In a recent issue of Critical Care, Brandt and colleagues report the effects of a 'liberal' fluid loading protocol compared to a more 'restrictive' protocol on hemodynamics and mortality in pigs in which septic shock had been induced. It appears that the former protocol was associated with higher mortality in spite of improved hemodynamics compared to the latter. The results of the paper are discussed here in view of the scope and mechanisms of these findings. With regard to fluid resuscitation, they indicate that too much of an otherwise good thing is harmful, even if overhydration and edema formation seem to have been prevented. They also do not exclude a specific toxic effect of the larger volumes of hydroxyethyl starch in the 'liberal' strategy. The precise nature of a toxic effect remains obscure, however, but may involve the kidneys.

Fluid balance and acute kidney injury

Intravenous fluids are widely administered to patients who have, or are at risk of, acute kidney injury (AKI). However, deleterious consequences of overzealous fluid therapy are increasingly being recognized. Salt and water overload can predispose to organ dysfunction, impaired wound healing and nosocomial infection, particularly in patients with AKI, in whom fluid challenges are frequent and excretion is impaired. In this Review article, we discuss how interstitial edema can further delay renal recovery and why conservative fluid strategies are now being advocated. Applying these strategies in critical illness is challenging. Although volume resuscitation is needed to restore cardiac output, it often leads to tissue edema, thereby contributing to ongoing organ dysfunction. Conservative strategies of fluid management mandate a switch towards neutral balance and then negative balance once hemodynamic stabilization is achieved. In patients with AKI, this strategy might require renal replacement therapy to be given earlier than when more-liberal fluid management is used. However, hypovolemia and renal hypoperfusion can occur in patients with AKI if excessive fluid removal is pursued with diuretics or extracorporeal therapy. Thus, accurate assessment of fluid status and careful definition of targets are needed at all stages to improve clinical outcomes. A conservative strategy of fluid management was recently tested and found to be effective in a large, randomized, controlled trial in patients with acute lung injury. Similar randomized, controlled studies in patients with AKI now seem justified.

Physiologic predictors of postoperative abscess in children with perforated appendicitis: subset analysis from a prospective randomized trial

BACKGROUND

Intra-abdominal abscess after appendectomy is the most common complication in patients with perforated appendicitis. There are currently little data that may forecast which patients are more likely to develop an abscess. Therefore, we performed a retrospective analysis of a prospectively collected dataset to determine whether there are predictors for developing a postoperative abscess.

METHODS

The dataset was collected prospectively in a randomized trial comparing antibiotic regimens in 98 pediatric patients with perforated appendicitis. All patients underwent laparoscopic appendectomy and received a minimum of 5 days of intravenous antibiotics. The Pearson correlation was used to evaluate the influence of patient, intra-operative, and early postoperative variables on the development of an abscess. Two-tailed P values were determined from the correlation coefficient, and significance was defined as P < or = .05.

RESULTS

At presentation, a positive correlation for abscess formation was identified with increasing age (P = .003), weight (P = .001), body mass index (P = .008), and diarrhea (P = .005). Operative time had no influence on abscess development. After operation, there was progressively increasing positive correlation between abscess and the maximum temperature each successive postoperative day. This relationship became significant at day 3. An increased white blood cell count on day 5 was highly predictive of abscess (P < .001).

CONCLUSION

In children presenting with perforated appendicitis, increasing age, weight, and/or body mass index correlated with the development of a postoperative abscess. Diarrhea on presentation also poses an increased risk of abscess. Postoperatively, each successive day with a fever is incrementally more predictive of an abscess formation.