Preoperative optimization of cardiovascular hemodynamics improves outcome in peripheral vascular surgery. A prospective, randomized clinical trial

2024 AHA/ACC/ACS/ASNC/HRS/SCA/SCCT/SCMR/SVM Guideline for Perioperative Cardiovascular Management for Noncardiac Surgery: A Report of the American College of Cardiology/American Heart Association Joint Committee on Clinical Practice Guidelines

AIM

The "2024 AHA/ACC/ACS/ASNC/HRS/SCA/SCCT/SCMR/SVM Guideline for Perioperative Cardiovascular Management for Noncardiac Surgery" provides recommendations to guide clinicians in the perioperative cardiovascular evaluation and management of adult patients undergoing noncardiac surgery.

METHODS

A comprehensive literature search was conducted from August 2022 to March 2023 to identify clinical studies, reviews, and other evidence conducted on human subjects that were published in English from MEDLINE (through PubMed), EMBASE, the Cochrane Library, the Agency for Healthcare Research and Quality, and other selected databases relevant to this guideline.

STRUCTURE

Recommendations from the "2014 ACC/AHA Guideline on Perioperative Cardiovascular Evaluation and Management of Patients Undergoing Noncardiac Surgery" have been updated with new evidence consolidated to guide clinicians; clinicians should be advised this guideline supersedes the previously published 2014 guideline. In addition, evidence-based management strategies, including pharmacological therapies, perioperative monitoring, and devices, for cardiovascular disease and associated medical conditions, have been developed.

Enhanced recovery after surgery (ERAS) for vascular surgery: an evidence map and scoping review

BACKGROUND

Enhanced recovery after surgery (ERAS) interventions aim to improve patient outcomes. Vascular surgery patients have unique requirements and it is unclear which ERAS interventions are supported by an evidence base.

METHODS

We conducted a scoping review to identify ERAS randomized controlled trials (RCTs) published in the biomedical or nursing literature. We assessed interventions for applicability to vascular surgery and differentiated interventions given at preadmission, preoperative, intraoperative, and postoperative surgery stages. We documented the research in an evidence map.

RESULTS

We identified 76 relevant RCTs. Interventions were mostly administered in preoperative (23 RCTs; 30%) or intraoperative surgery stages (35 RCTs; 46%). The majority of studies reported mortality outcomes (44 RCTs; 58%), but hospital (27 RCTs; 35%) and intensive care unit (9 RCTs; 12%) length of stay outcomes were less consistently described.

CONCLUSION

The ERAS evidence base is growing but contains gaps. Research on preadmission interventions and more consistent reporting of key outcomes is needed.

Surgical Science and the Evolution of Critical Care Medicine

Surgical science has driven innovation and inquiry across adult and pediatric disciplines that provide critical care regardless of location. Surgically originated but broadly applicable knowledge has been globally shared within the pages Critical Care Medicine over the last 50 years.

Handling high-risk patients in the catheterization laboratory

Protected percutaneous coronary intervention is considered a life-saving procedure for high-risk patients. Therefore it is important that the interventional cardiology team is prepared, the procedure is planned, and potential complications, as well as bail out strategies are considered. Throughout the procedure, it is critical to monitor the patient to identify any early signs of deterioration or changes in patient well-being to avoid any potential complications.

[Targeted hemodynamic monitoring in the operating theatre: what for and by what means?]

Goal directed hemodynamic monitoring and the balance in goal directed therapy between adequate fluid/volume therapy and the application of vasoactive or inotropic drugs are the basic elements of modern perioperative therapy.Surgical procedures should be accompanied by as few side effects and complications as possible. Nevertheless, the number of postoperative complications remains surprisingly high, despite of the modern surgical procedures. Anticipation of potential complications in the perioperative period and their rapid treatment build a core competence of anesthesiological action. Thus, it is clear that anesthesia plays a central role in this balancing act.This article aims to provide an overview of the application of the currently available perioperative goal directed hemodynamic monitoring. The current possibilities are discussed by using a case example and an outlook on the future of hemodynamic monitoring is given.

To Swan or Not to Swan: Indications, Alternatives, and Future Directions

The pulmonary artery catheter (PAC) has revolutionized bedside assessment of preload, afterload, and contractility using measured pulmonary capillary wedge pressure, calculated systemic vascular resistance, and estimated cardiac output. It is placed percutaneously by a flow-directed balloon-tipped technique through the venous system and the right heart to the pulmonary artery. Interest in the hemodynamic variables obtained from PACs paved the way for the development of numerous less-invasive hemodynamic monitors over the past 3 decades. These devices estimate cardiac output using concepts such as pulse contour and pressure analysis, transpulmonary thermodilution, carbon dioxide rebreathing, impedance plethysmography, Doppler ultrasonography, and echocardiography. Herein, the authors review the conception, technologic advancements, and modern use of PACs, as well as the criticisms regarding the clinical utility, reliability, and safety of PACs. The authors comment on the current understanding of the benefits and limitations of alternative hemodynamic monitors, which is important for providers caring for critically ill patients. The authors also briefly discuss the use of hemodynamic monitoring in goal-directed fluid therapy algorithms in Enhanced Recovery After Surgery programs.

[Perioperative fluid management]

An appropriate perioperative infusion management is pivotal for the perioperative outcome of the patient. Optimization of the perioperative fluid treatment often results in enhanced postoperative outcome, reduced perioperative complications and shortened hospitalization. Hypovolemia as well as hypervolemia can lead to an increased rate of perioperative complications. The main goal is to maintain perioperative euvolemia by goal-directed therapy (GDT), a combination of fluid management and inotropic medication, to optimize perfusion conditions in the perioperative period; however, perioperative fluid management should also include the preoperative and postoperative periods. This encompasses the preoperative administration of carbohydrate-rich drinks up to 2 h before surgery. In the postoperative period, patients should be encouraged to start per os hydration early and excessive i.v. fluid administration should be avoided. Implementation of a comprehensive multimodal, goal-directed fluid management within an enhanced recovery after surgery (ERAS) protocol is efficient but the exact status of indovodual items remains unclear at present.

Does goal-directed haemodynamic and fluid therapy improve peri-operative outcomes?: A systematic review and meta-analysis

BACKGROUND

Much uncertainty exists as to whether peri-operative goal-directed therapy is of benefit.

OBJECTIVES

To discover if peri-operative goal-directed therapy decreases mortality and morbidity in adult surgical patients.

DESIGN

An updated systematic review and random effects meta-analysis of randomised controlled trials.

DATA SOURCES

Medline, Embase and the Cochrane Library were searched up to 31 December 2016.

ELIGIBILITY CRITERIA

Randomised controlled trials enrolling adult surgical patients allocated to receive goal-directed therapy or standard care were eligible for inclusion. Trauma patients and parturients were excluded. Goal-directed therapy was defined as fluid and/or vasopressor therapy titrated to haemodynamic goals [e.g. cardiac output (CO)]. Outcomes included mortality, morbidity and hospital length of stay. Risk of bias was assessed using Cochrane methodology.

RESULTS

Ninety-five randomised trials (11 659 patients) were included. Only four studies were at low risk of bias. Modern goal-directed therapy reduced mortality compared with standard care [odds ratio (OR) 0.66; 95% confidence interval (CI) 0.50 to 0.87; number needed to treat = 59; N = 52; I = 0.0%]. In subgroup analysis, there was no mortality benefit for fluid-only goal-directed therapy, cardiac surgery patients or nonelective surgery. Contemporary goal-directed therapy also reduced pneumonia (OR 0.69; 95% CI, 0.51 to 0. 92; number needed to treat = 38), acute kidney injury (OR 0. 73; 95% CI, 0.58 to 0.92; number needed to treat = 29), wound infection (OR 0.48; 95% CI, 0.37 to 0.63; number needed to treat = 19) and hospital length of stay (days) (-0.90; 95% CI, -1.32 to -0.48; I = 81. 2%). No important differences in outcomes were found for the pulmonary artery catheter studies, after accounting for advances in the standard of care.

CONCLUSION

Peri-operative modern goal-directed therapy reduces morbidity and mortality. Importantly, the quality of evidence was low to very low (e.g. Grading of Recommendations, Assessment, Development and Evaluation scoring), and there was much clinical heterogeneity among the goal-directed therapy devices and protocols. Additional well designed and adequately powered trials on peri-operative goal-directed therapy are necessary.

Hemodynamic goal-directed therapy and postoperative kidney injury: an updated meta-analysis with trial sequential analysis

Background

Perioperative goal-directed therapy (GDT) reduces the risk of renal injury. However, several questions remain unanswered, such as target, kind of patients and surgery, and role of fluids and inotropes. We therefore update a previous analysis, including all studies published in the meanwhile, to clarify the clinical impact of this strategy on acute kidney injury.

Main body

Randomized controlled trials enrolling adult patients undergoing major surgery were considered. GDT was defined as perioperative monitoring and manipulation of hemodynamic parameters to reach normal or supranormal values by fluids alone or with inotropes. Trials comparing the effects of GDT and standard hemodynamic therapy were considered. Primary outcome was acute kidney injury, whichever definition was used. Meta-analytic techniques (analysis software RevMan, version 5.3) were used to combine studies, using random-effect odds ratios (OR) and 95% confidence intervals (CI). Trial sequential analyses were performed including all trials and considering only low risk of bias trials. Sixty-five trials with an overall sample of 9308 patients were included. OR for the development of renal injury was 0.64 (95% CI, 0.62–0.87; p = 0.0003), with no statistical heterogeneity. Trial sequential analyses and sensitivity analysis including studies with low risk of bias confirmed the main results. A significant decrease in renal injury rate was observed in studies that adopted cardiac output and oxygen delivery as hemodynamic target and that used both fluids and inotropes. The postoperative kidney injury rate was significantly lower in trials enrolling “high-risk” patients and major abdominal and orthopedic surgery.

Short conclusion

The present meta-analysis suggests that targeting GDT to perioperative systemic oxygen delivery, by means of fluids and inotropes, can be the best way to improve renal perfusion and oxygenation in high-risk patients undergoing major abdominal and orthopedic surgery.

Electronic supplementary material

The online version of this article (10.1186/s13054-019-2516-4) contains supplementary material, which is available to authorized users.

Perioperative goal-directed therapy - What is the evidence?

Perioperative goal-directed therapy aims at optimizing global hemodynamics during the perioperative period by titrating fluids, vasopressors, and/or inotropes to predefined hemodynamic goals. There is evidence on the benefit of perioperative goal-directed therapy, but its adoption into clinical practice is slow and incomprehensive. Current evidence indicates that treating patients according to perioperative goal-directed therapy protocols reduces morbidity and mortality, particularly in patients having high-risk surgery. Perioperative goal-directed therapy protocols need to be started early, should include vasoactive agents in addition to fluids, and should target blood flow related variables. Future promising developments in the field of perioperative goal-directed therapy include personalized hemodynamic management and closed-loop system management.

Perioperative goal-directed therapy: A systematic review without meta-analysis

BACKGROUND

Perioperative goal-directed therapy aims to optimise haemodynamics by titrating fluids, vasopressors and/or inotropes to predefined haemodynamic targets. Perioperative goal-directed therapy is a complex intervention composed of several independent component interventions. Trials on perioperative goal-directed therapy show conflicting results. We aimed to conduct a systematic review and meta-analysis to investigate the benefits and harms of perioperative goal-directed therapy.

METHODS

PubMED, EMBASE, Web of Science and Cochrane Library were searched. Trials were included if they had a perioperative goal-directed therapy protocol. The primary outcome was all-cause mortality. The first secondary outcome was serious adverse events excluding mortality. Risk of bias was assessed, and GRADE was used to evaluate quality of evidence.

RESULTS

One hundred and twelve randomised trials were included of which one trial (1%) had low risk of bias. Included trials varied in patients: types of surgery which was expected due to inclusion criteria; in intervention and comparison: timing of intervention, monitoring devices, haemodynamic variables, target values, use of fluids, vasopressors and/or inotropes as well as combinations of these within protocols; and in outcome: mortality was reported in 87 trials (78%). Due to substantial clinical heterogeneity also within the various types of surgery a meta-analysis of data, including subgroup analyses, as defined in our protocol was considered inappropriate.

CONCLUSION

Clinical heterogeneity in patients, interventions and outcomes in perioperative goal-directed therapy trials is too large to perform meta-analysis on all trials. Future trials and meta-analyses highly depend on universally agreed definitions on aspects beyond type of surgery of the complex intervention and its evaluation.

Iso-osmolar prehydration shifts the cytokine response towards a more anti-inflammatory balance in human endotoxemia

Clinical experience suggests that the administration of fluids in human endotoxemia reduces symptoms. In the present study, the effects of a standardised fluid protocol on symptoms, inflammatory and hemodynamic parameters in human endotoxemia are determined. With approval of the local ethics committee, 16 healthy volunteers received 2 ng/kg of Escherichia coli endotoxin (O:113). After an overnight fast, nine subjects received 1.5 l of 2.5% glucose/0.45% NaCl the hour prior to the endotoxin administration and 150 ml/h during the course of the experiment (`prehydrated group'). Seven subjects only received a continuous infusion of 75 ml/h during the experiment (`non-prehydrated group'). The course of inflammatory parameters and symptoms were determined and mean arterial pressure, heart rate and forearm blood flow were measured. In the prehydrated group, TNF-α increased to 522 ± 63 pg/ml (mean ± SEM) while the maximum in the non-prehydrated group was 927 ± 187 pg/ml ( P < 0.04). IL-10 increased similarly in both groups (non-prehydrated 117 ± 18 pg/ml and prehydrated 99 ± 18 pg/ml; P = NS). The prehydrated group had a significantly lower ( P < 0.004) symptom score and recovered sooner ( P = 0.004). Endotoxin-induced changes in hemodynamics revealed no significant differences between groups. We demonstrate that prehydration in experimental human endotoxemia significantly shifts the cytokine balance towards a more anti-inflammatory pattern. This effect is associated with a reduction in symptoms, whereas the changes in hemodynamic parameters are not influenced by prehydration.

The Pulmonary Artery Catheter in Anesthesia Practice in 2007: An Historical Overview With Emphasis on the Past 6 Years

The pulmonary artery catheter has been widely used in anesthesiology and critical care medicine. Until recently, only retrospective or relatively weak prospective studies examining its effect on outcome had been performed. Over the past 6 years, however, a number of well-designed prospective trials and statistically sound retrospective studies have been completed. All of these show no benefit and some even reveal a potential for increased morbidity. Reasons for this device's inability to improve outcome are numerous, including wrong patient selection and misinterpretation, but the most impressive and convincing evidence is that filling pressures measured from the catheter, particularly the pulmonary artery “wedge” pressure, have no physiologic value. The wedge pressure has been shown to not correlate with other accepted methods of determining left ventricular filling or volume or intravascular volume and also does not help to generate cardiac function curves. Therefore, knowledge of it may actually lead to incorrect management more frequently than not.

Pain Management After Vascular Surgery

Patients presenting for vascular surgery usually have concomitant disease processes that may increase the likelihood of adverse outcomes after major surgery. Because of the advanced nature of the underlying medical condition, it is important to optimize postopera tive pain control to adequately control postoperative discomfort, stress response, hypercoagulability, myocar dial ischemia, and graft failure. This article discusses methods of pain control after vascular surgery and their effects on physiology and outcome.

Targeting Oliguria Reversal in Goal-Directed Hemodynamic Management Does Not Reduce Renal Dysfunction in Perioperative and Critically Ill Patients: A Systematic Review and Meta-Analysis

BACKGROUND

We investigated whether resuscitation protocols to achieve and maintain urine output above a predefined threshold-including oliguria reversal as a target--prevent acute renal failure (ARF).

METHODS

We performed a systematic review and meta-analysis using studies found by searching MEDLINE, EMBASE, and references in relevant reviews and articles. We included all studies that compared "conventional fluid management" (CFM) with "goal-directed therapy" (GDT) using cardiac output, urine output, or oxygen delivery parameters and reported the occurrence of ARF in critically ill or surgical patients. We divided studies into groups with and without oliguria reversal as a target for hemodynamic optimization. We calculated the combined odds ratio (OR) and 95% confidence intervals (CIs) using random-effects meta-analysis.

RESULTS

We based our analyses on 28 studies. In the overall analysis, GDT resulted in less ARF than CFM (OR, 0.58; 95% CI, 0.44-0.76; P < 0.001; I = 34.3%; n = 28). GDT without oliguria reversal as a target resulted in less ARF (OR, 0.45; 95% CI, 0.34-0.61; P < 0.001; I = 7.1%; n = 7) when compared with CFM with oliguria reversal as a target. The studies comparing GDT with CFM in which the reversal of oliguria was targeted in both or in neither group did not provide enough evidence to conclude a superiority of GDT (targeting oliguria reversal in both protocols: OR, 0.63; 95% CI, 0.36-1.10; P = 0.09; I = 48.6%; n = 9, and in neither protocol: OR, 0.66; 95% CI, 0.37-1.16; P = 0.14; I = 20.2%; n = 12).

CONCLUSIONS

Current literature favors targeting circulatory optimization by GDT without targeting oliguria reversal to prevent ARF. Future studies are needed to investigate the hypothesis that targeting oliguria reversal does not prevent ARF in critically ill and surgical patients.

Algorithm-guided goal-directed haemodynamic therapy does not improve renal function after major abdominal surgery compared to good standard clinical care: a prospective randomised trial

BACKGROUND

Acute kidney injury is a common complication after major surgery. In this study, we investigated whether an algorithm-guided goal-directed haemodynamic therapy (GDT) can improve renal outcome compared to good standard clinical care.

METHODS

A total of 180 patients undergoing major abdominal surgery were prospectively and randomly assigned to one of two groups: in the GDT group, patients were treated with a GDT algorithm using transpulmonary thermodilution while standard care was applied to the control patients. Change in creatinine was studied as the primary end point, postoperative complications as well as 1-year mortality as secondary outcomes. Haemodynamics in GDT and control patients were compared calculating goal-achievement rates.

RESULTS

Postoperative change in creatinine (18 ± 39 μmol/l (control) vs. 16 ± 42 μmol/l (GDT); mean difference (95 % confidence interval) 1.6 μmol/l (-10 to 13 μmol/l)) was comparable between the GDT and the control group. Postoperative complications and mortality during hospital stay and after 1 year were not influenced by the use of a GDT algorithm. Achievement rates of haemodynamic goals were not higher in the GDT group compared to the already high (>80 %) rates in the control group. Multivariate regression analysis revealed intraoperative hypotension (MAP < 70 mmHg) and postoperative hypovolaemia (GEDI < 640 ml/m(2)) as risk factors for postoperative renal impairment.

CONCLUSIONS

In this study, GDT was not superior to standard clinical care in order to avoid renal failure after major abdominal surgery. The reason for this finding is most likely the high achievement rate of haemodynamic goals in the control group, which cannot be improved by the GDT algorithm.

TRIAL REGISTRATION

Clinicaltrials.gov; NCT01035541; registered 17 December 2009.

Preoperative optimization of the vascular surgery patient

It is well known that patients who suffer from peripheral (noncardiac) vascular disease often have coexisting atherosclerotic diseases of the heart. This may leave the patients susceptible to major adverse cardiac events, including death, myocardial infarction, unstable angina, and pulmonary edema, during the perioperative time period, in addition to the many other complications they may sustain as they undergo vascular surgery procedures, regardless of whether the procedure is performed as an open or endovascular modality. As these patients are at particularly high risk, up to 16% in published studies, for postoperative cardiac complications, many proposals and algorithms for perioperative optimization have been suggested and studied in the literature. Moreover, in patients with recent coronary stents, the risk of non-cardiac surgery on adverse cardiac events is incremental in the first 6 months following stent implantation. Just as postoperative management of patients is vital to the outcome of a patient, preoperative assessment and optimization may reduce, and possibly completely alleviate, the risks of major postoperative complications, as well as assist in the decision-making process regarding the appropriate surgical and anesthetic management. This review article addresses several tools and therapies that treating physicians may employ to medically optimize a patient before they undergo noncardiac vascular surgery.

[Goal-directed hemodynamic therapy: Concepts, indications and risks]

Goal-directed hemodynamic therapy is becoming increasingly more interesting for anesthesiologists and intensive care physicians. Meta-analyses of studies evaluating perioperative therapy algorithms demonstrated a reduction of postoperative morbidity compared to the previous clinical practices. In this review article the basic concepts of goal-directed hemodynamic therapy and the principles of previously employed therapy algorithms are described and discussed. Furthermore, the questions of how these therapy strategies can be transferred into daily clinical practice and whether these therapeutic approaches might even bear risks for patients are elucidated.

Diagnosis of cardiogenic shock without the use of a pulmonary artery catheter

BACKGROUND

Current diagnostic criteria for cardiogenic shock (CS) require the use of a pulmonary artery catheter (PAC), which is time-consuming and may cause complications. A set of simple yet accurate noninvasive diagnostic criteria would be of significant utility.

METHODS

Candidate components for the Noninvasive Parameters for Assessment of Cardiogenic Shock (N-PACS) criteria were required to be objective, readily available, and noninvasive. Variables encompassing hypotension, hypoperfusion, predisposing conditions, and elevated intracardiac filling pressures were optimized versus a PAC-based standard in a retrospective developmental cohort of 122 patients with acute myocardial infarction (AMI). The finalized criteria were validated in a prospective cohort of coronary care unit patients in whom a PAC was placed for clinical indications.

RESULTS

According to invasive criteria, CS was present in 32 of 217 consecutive patients undergoing PAC. Compared to the PAC-based standard, the N-PACS criteria had a sensitivity of 96.9% (95% confidence interval (CI) 82.0-99.8), specificity of 90.8% (95% CI 85.5-94.4), positive predictive value of 64.6% (95% CI 49.4-77.4), negative predictive value of 99.4% (95% CI 96.2-100), positive likelihood ratio of 10.5 (95% CI 6.7-16.7), negative likelihood ratio of 0.03 (95% CI 0.00-0.24), and diagnostic odds ratio of 306.4. Results were similar among patients with and without AMI.

CONCLUSION

A simple, echocardiography-based set of noninvasive diagnostic criteria can be used to accurately diagnose CS.

Perioperative Haemodynamic Optimisation

During the latest years, a number of studies have confirmed the benefits of perioperative haemodynamic optimisation on surgical mortality and postoperative complication rate. This process requires the use of advanced haemodynamic monitoring with the purpose of guiding therapies to reach predefined goals. This review aim to present recent evidence on perioperative goal directed therapy (GDT), with an emphasis in some aspects that may merit further investigation. In order to maximise the benefits on outcomes, GDT must be implemented as early as possible; intravascular volume optimisation should be in accordance with the response of the preload-reserve, goals should be individualised and adequacy of the intervention must be also assessed; non-invasive or minimally invasive monitoring should be used and, finally, side effects of every therapy should be taken into account in order to avoid undesired complications. New drugs and technologies, particularly those exploring the venous side of the circulation, may improve in the future the effectiveness and facilitate the implementation of this group of therapeutic interventions.

Optimizing perioperative hemodynamics: what is new?

PURPOSE OF REVIEW

Using perioperative goal-directed therapy (GDT) or peroperative hemodynamic optimization significantly reduces postoperative complications and risk of death in patients undergoing noncardiac major surgeries. In this review, we discuss the main changes in the field of perioperative optimization over the last few years.

RECENT FINDINGS

One of the key aspects that has changed in the last decade is the shift from invasive monitoring with pulmonary artery catheters (PACs) to less or minimally invasive monitoring systems. The evaluation of intravascular fluid volume deficits has also changed dramatically from the use of static indices to the assessment of fluid responsiveness using either dynamic indices or functional hemodynamic. Finally, attention has been directed toward more restrictive strategies of crystalloids as maintenance fluids.

SUMMARY

GDT is safe and more likely to tailor the amount of fluids given to the amount of fluids actually needed. This approach includes assessment of fluid responsiveness and, if necessary, the use of inotropes; moreover, this approach can be coupled with a restrictive strategy for maintenance fluids. These strategies have been increasingly incorporated into protocols for perioperative hemodynamic optimization in high-risk patients undergoing major surgery, resulting in more appropriate use of fluids, vasopressors, and inotropes.

Cardiac complications associated with goal-directed therapy in high-risk surgical patients: a meta-analysis

Patients with limited cardiopulmonary reserve are at risk of mortality and morbidity after major surgery. Augmentation of oxygen delivery index (DO2I) with i.v. fluids and inotropes (goal-directed therapy, GDT) has been shown to reduce postoperative mortality and morbidity in high-risk patients. Concerns regarding cardiac complications associated with fluid challenges and inotropes may prevent clinicians from performing GDT in patients who need it most. We hypothesized that GDT is not associated with an increased risk of cardiac complications in high-risk, non-cardiac surgical patients. We performed a systematic search of Medline, Embase, and CENTRAL databases for randomized controlled trials (RCTs) of GDT in high-risk surgical patients. Studies including cardiac surgery, trauma, and paediatric surgery were excluded. We reviewed the rates of all cardiac complications, arrhythmias, myocardial ischaemia, and acute pulmonary oedema. Meta-analyses were performed using RevMan software. Data are presented as odds ratios (ORs), [95% confidence intervals (CIs)], and P-values. Twenty-two RCTs including 2129 patients reported cardiac complications. GDT was associated with a reduction in total cardiovascular (CVS) complications [OR=0.54, (0.38-0.76), P=0.0005] and arrhythmias [OR=0.54, (0.35-0.85), P=0.007]. GDT was not associated with an increase in acute pulmonary oedema [OR=0.69, (0.43-1.10), P=0.12] or myocardial ischaemia [OR=0.70, (0.38-1.28), P=0.25]. Subgroup analysis revealed the benefit is most pronounced in patients receiving fluid and inotrope therapy to achieve a supranormal DO2I, with the use of minimally invasive cardiac output monitors. Treatment of high-risk surgical patients GDT is not associated with an increased risk of cardiac complications; GDT with fluids and inotropes to optimize DO2I during early GDT reduces postoperative CVS complications.

Protocoled resuscitation and the prevention of acute kidney injury

PURPOSE OF REVIEW

Acute kidney injury (AKI) occurrence in critically ill patients is common and is associated with a substantial increase in morbidity and mortality. The scope of this review is to summarize the most recent evidence-based knowledge for prevention of AKI.

RECENT FINDINGS

Recent recommendations for prevention of AKI in ICU patients are all 'negative' and, similarly, the most recent and updated guidelines about major topic areas of interest for AKI, including definition and classification, prevention, and pharmacologic treatment, have failed to identify single evidence-based recommendations for prevention and treatment of AKI. Therefore, the evaluation and management of AKI should be guided by clinical algorithms aiming to protocolized hemodynamic optimization, metabolic control, monitoring of intra-abdominal hypertension, use of diuretics to control fluid overload, and careful management of nephrotoxic factors.

SUMMARY

Key components of optimal AKI prevention include maintenance of renal perfusion and avoidance of precipitating factors. Adequate renal blood flow maintenance is the first strategy to employ not only to assure renal oxygenation, but also to prevent nephrotoxic drugs-associated AKI. Many potential therapies and interventions are on the horizon, but most of the future research will need to focus more on a step-wise, protocoled, kidney-oriented approach, than on single treatments.

Perioperative increase in global blood flow to explicit defined goals and outcomes after surgery: a Cochrane Systematic Review

This systematic review and meta-analysis summarizes the clinical effects of increasing perioperative blood flow using fluids with or without inotropes/vasoactive drugs to explicit defined goals in adults. We included randomized controlled trials of adult patients (aged 16 years or older) undergoing surgery. We included 31 studies of 5292 participants. There was no difference in mortality at the longest follow-up: 282/2615 (10.8%) died in the control group and 238/2677 (8.9%) in the treatment group, RR of 0.89 (95% CI: 0.76-1.05; P=0.18). However, the results were sensitive to analytical methods and withdrawal of studies with methodological limitations. The intervention reduced the rate of three morbidities (renal failure, respiratory failure, and wound infections) but not the rates of arrhythmia, myocardial infarction, congestive cardiac failure, venous thrombosis, and other types of infections. The number of patients with complications was also reduced by the intervention. Hospital length of stay was reduced in the treatment group by 1.16 days. There was no difference in critical care length of stay. The primary analysis of this review showed no difference between groups but this result was sensitive to the method of analysis, withdrawal of studies with methodological limitations, and was dominated by a single large study. Patients receiving this intervention stayed in hospital 1 day less with fewer complications. It is unlikely that the intervention causes harm. The balance of current evidence does not support widespread implementation of this approach to reduce mortality but does suggest that complications and duration of hospital stay are reduced.

Clinical review: What are the best hemodynamic targets for noncardiac surgical patients?

Perioperative hemodynamic optimization, or goal-directed therapy (GDT), has been show to significantly decrease complications and risk of death in high-risk patients undergoing noncardiac surgery. An important aim of GDT is to prevent an imbalance between oxygen delivery and oxygen consumption in order to avoid the development of multiple organ dysfunction. The utilization of cardiac output monitoring in the perioperative period has been shown to improve outcomes if integrated into a GDT strategy. GDT guided by dynamic predictors of fluid responsiveness or functional hemodynamics with minimally invasive cardiac output monitoring is suitable for the majority of patients undergoing major surgery with expected significant volume shifts due to bleeding or other significant intravascular volume losses. For patients at higher risk of complications and death, such as those with advanced age and limited cardiorespiratory reserve, the addition of dobutamine or dopexamine to the treatment algorithm, to maximize oxygen delivery, is associated with better outcomes.

Clinical review: Goal-directed therapy-what is the evidence in surgical patients? The effect on different risk groups

Patients with limited cardiac reserve are less likely to survive and develop more complications following major surgery. By augmenting oxygen delivery index (DO₂I) with a combination of intravenous fluids and inotropes (goal directed therapy (GDT)), postoperative mortality and morbidity of high-risk patients may be reduced. However, although most studies suggest that GDT may improve outcome in high-risk surgical patients, it is still not widely practiced. We set out to test the hypothesis that GDT results in greatest benefit in terms of mortality and morbidity in patients with the highest risk of mortality and have undertaken a systematic review of the current literature to see if this is correct. We performed a systematic search of Medline, Embase and CENTRAL databases for randomized controlled trials (RCTs) and reviews of GDT in surgical patients. To minimize heterogeneity we excluded studies involving cardiac, trauma, and paediatric surgery. Extremely high risk, high risk and intermediate risks of mortality were defined as >20%, 5 to 20% and <5% mortality rates in the control arms of the trials, respectively. Meta analyses were performed and Forest plots drawn using RevMan software. Data are presented as odd ratios (OR; 95% confidence intervals (CI), and P-values). A total of 32 RCTs including 2,808 patients were reviewed. All studies reported mortality. Five studies (including 300 patients) were excluded from assessment of complication rates as the number of patients with complications was not reported. The mortality benefit of GDT was confined to the extremely high-risk group (OR = 0.20, 95% CI 0.09 to 0.41; P < 0.0001). Complication rates were reduced in all subgroups (OR = 0.45, 95% CI 0.34 to 0.60; P < 0.00001). The morbidity benefit was greatest amongst patients in the extremely high-risk subgroup (OR = 0.27, 95% CI 0.15 to 0.51; P < 0.0001), followed by the intermediate risk subgroup (OR = 0.43, 95% CI 0.27 to 0.67; P = 0.0002), and the high-risk subgroup (OR 0.56, 95% CI 0.36 to 0.89; P = 0.01). Despite heterogeneity in trial quality and design, we found GDT to be beneficial in all high-risk patients undergoing major surgery. The mortality benefit of GDT was confined to the subgroup of patients at extremely high risk of death. The reduction of complication rates was seen across all subgroups of GDT patients.

Pulmonary artery catheters for adult patients in intensive care

BACKGROUND

Since pulmonary artery balloon flotation catheterization was first introduced in 1970, by HJ Swan and W Ganz, it has been widely disseminated as a diagnostic tool without rigorous evaluation of its clinical utility and effectiveness in critically ill patients. A pulmonary artery catheter (PAC) is inserted through a central venous access into the right side of the heart and floated into the pulmonary artery. PAC is used to measure stroke volume, cardiac output, mixed venous oxygen saturation and intracardiac pressures with a variety of additional calculated variables to guide diagnosis and treatment. Complications of the procedure are mainly related to line insertion. Relatively uncommon complications include cardiac arrhythmias, pulmonary haemorrhage and infarct, and associated mortality from balloon tip rupture.

OBJECTIVES

To provide an up-to-date assessment of the effectiveness of a PAC on mortality, length of stay (LOS) in intensive care unit (ICU) and hospital and cost of care in adult intensive care patients.

SEARCH METHODS

We searched the Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library 2011, Issue 12); MEDLINE (1954 to January 2012); EMBASE (1980 to January 2012); CINAHL (1982 to January 2012), and reference lists of articles. We contacted researchers in the field. We did a grey literature search for articles published until January 2012.

SELECTION CRITERIA

We included all randomized controlled trials conducted in adults ICUs, comparing management with and without a PAC.

DATA COLLECTION AND ANALYSIS

We screened the titles and abstracts and then the full text reports identified from our electronic search. Two authors (SR and MG) independently reviewed the titles, abstracts and then the full text reports for inclusion. We determined the final list of included studies by discussion among the group members (SR, ND, MG, AK and SC) with consensus agreement. We included all the studies that were in the original review. We assessed seven domains of potential risk of bias for the included studies. We examined the clinical, methodological and statistical heterogeneity and used random-effects model for meta-analysis. We calculated risk ratio for mortality across studies and mean days for LOS.

MAIN RESULTS

We included 13 studies (5686 patients). We judged blinding of participants and personnel and blinding of outcome assessment to be at high risk in about 50% of the included studies and at low risk in 25% to 30% of the studies. Regardless of the high risk of performance bias these studies were included based on the low weight the studies had in the meta-analysis. We rated 75% of the studies as low risk for selection, attrition and reporting bias. All 13 studies reported some type of hospital mortality (28-day, 30-day, 60-day or ICU mortality). We considered studies of high-risk surgery patients (eight studies) and general intensive care patients (five studies) separately as subgroups for meta-analysis. The pooled risk ratio (RR) for mortality for the studies of general intensive care patients was 1.02 (95% confidence interval (CI) 0.96 to 1.09) and for the studies of high-risk surgery patients the RR was 0.98 (95% CI 0.74 to 1.29). Of the eight studies of high-risk surgery patients, five evaluated the effectiveness of pre-operative optimization but there was no difference in mortality when these studies were examined separately. PAC did not affect general ICU LOS (reported by four studies) or hospital LOS (reported by nine studies). Four studies, conducted in the United States (US), reported costs based on hospital charges billed, which on average were higher in the PAC groups. Two of these studies qualified for analysis and did not show a statistically significant hospital cost difference (mean difference USD 900, 95% CI -2620 to 4420, P = 0.62).

AUTHORS' CONCLUSIONS

PAC is a diagnostic and haemodynamic monitoring tool but not a therapeutic intervention. Our review concluded that use of a PAC did not alter the mortality, general ICU or hospital LOS, or cost for adult patients in intensive care. The quality of evidence was high for mortality and LOS but low for cost analysis. Efficacy studies are needed to determine if there are optimal PAC-guided management protocols, which when applied to specific patient groups in ICUs could result in benefits such as shock reversal, improved organ function and less vasopressor use. Newer, less-invasive haemodynamic monitoring tools need to be validated against PAC prior to clinical use in critically ill patients.

Perioperative increase in global blood flow to explicit defined goals and outcomes following surgery

BACKGROUND

Studies have suggested that increasing whole body blood flow and oxygen delivery around the time of surgery reduces mortality, morbidity and the expense of major operations.

OBJECTIVES

To describe the effects of increasing perioperative blood flow using fluids with or without inotropes or vasoactive drugs. Outcomes were mortality, morbidity, resource utilization and health status.

SEARCH METHODS

We searched CENTRAL (The Cochrane Library 2012, Issue 1), MEDLINE (1966 to March 2012) and EMBASE (1982 to March 2012). We manually searched the proceedings of major conferences and personal reference databases up to December 2011. We contacted experts in the field and pharmaceutical companies for published and unpublished data.

SELECTION CRITERIA

We included randomized controlled trials with or without blinding. We included studies involving adult patients (aged 16 years or older) undergoing surgery (patients having a procedure in an operating room). The intervention met the following criteria. 'Perioperative' was defined as starting up to 24 hours before surgery and stopping up to six hours after surgery. 'Targeted to increase global blood flow' was defined by explicit measured goals that were greater than in controls, specifically one or more of cardiac index, oxygen delivery, oxygen consumption, stroke volume (and the respective derived indices), mixed venous oxygen saturation (SVO(2)), oxygen extraction ratio (0(2)ER) or lactate.

DATA COLLECTION AND ANALYSIS

Two authors independently extracted the data. We contacted study authors for additional data. We used Review Manager software.

MAIN RESULTS

We included 31 studies of 5292 participants. There was no difference in mortality: 282/2615 (10.8%) died in the control group and 238/2677 (8.9%) in the treatment group, RR of 0.89 (95% CI 0.76 to 1.05, P = 0.18). However, the results were sensitive to analytical methods and the intervention was better than control when inverse variance or Mantel-Haenszel random-effects models were used, RR of 0.72 (95% CI 0.55 to 0.95, P = 0.02). The results were also sensitive to withdrawal of studies with methodological limitations. The rates of three morbidities were reduced by increasing global blood flow: renal failure, RR of 0.71 (95% CI 0.57 to 0.90); respiratory failure, RR of 0.51 (95% CI 0.28 to 0.93); and wound infections, RR of 0.65 (95% CI 0.51 to 0.84). There were no differences in the rates of nine other morbidities: arrhythmia, pneumonia, sepsis, abdominal infection, urinary tract infection, myocardial infarction, congestive cardiac failure or pulmonary oedema, or venous thrombosis. The number of patients with complications was reduced by the intervention, RR of 0.68 (95% CI 0.58 to 0.80). Hospital length of stay was reduced in the treatment group by a mean of 1.16 days (95% CI 0.43 to 1.89, P = 0.002). There was no difference in critical care length of stay. There were insufficient data to comment on quality of life and cost effectiveness.

AUTHORS' CONCLUSIONS

It remains uncertain whether increasing blood flow using fluids, with or without inotropes or vasoactive drugs, reduces mortality in adults undergoing surgery. The primary analysis in this review (mortality at longest follow-up) showed no difference between the intervention and control, but this result was sensitive to the method of analysis, the withdrawal of studies with methodological limitations, and is dominated by a single large RCT. Overall, for every 100 patients in whom blood flow is increased perioperatively to defined goals, one can expect 13 in 100 patients (from 40/100 to 27/100) to avoid a complication, 2/100 to avoid renal impairment (from 8/100 to 6/100), 5/100 to avoid respiratory failure (from 10/100 to 5/100), and 4/100 to avoid postoperative wound infection (from 10/100 to 6/100). On average, patients receiving the intervention stay in hospital one day less. It is unlikely that the intervention causes harm. The balance of current evidence does not support widespread implementation of this approach to reduce mortality but does suggest that complications and duration of hospital stay are reduced.

Hemodynamic monitoring in the intensive care unit

Patients in the intensive care unit are often critically ill with inadequate tissue perfusion and oxygenation. This inadequate delivery of substrates at the cellular level is a common definition of shock. Hemodynamic monitoring is the observation of cardiovascular physiology. The purpose of hemodynamic monitoring is to identify abnormal physiology and intervene before complications, including organ failure and death, occur. The most common types of invasive hemodynamic monitors are central venous catheters, pulmonary artery catheters, and arterial pulse-wave analysis. Ultrasonography is a noninvasive alternative being used in intensive care units for hemodynamic measurements and assessments.

Haemodynamic goal-directed therapy in cardiac and vascular surgery. A systematic review and meta-analysis

In cardiovascular surgery, reduced organ perfusion and oxygen delivery contribute to increased postoperative morbidity and prolonged intensive care unit stay. Goal-directed therapy (GDT), a perioperative haemodynamic strategy aiming to increase cardiac output, is helpful in preventing postoperative complications, but studies in the context of cardiovascular surgery have produced conflicting results. The purpose of the present meta-analysis is to determine the effects of perioperative haemodynamic goal-directed therapy on mortality and morbidity in cardiac and vascular surgery. MEDLINE, EMBASE, The Cochrane Library and the DARE databases were searched until July 2011. Randomized controlled trials reporting on adult cardiac or vascular surgical patients managed with perioperative GDT or according to routine haemodynamic practice were included. Primary outcome measures were mortality and morbidity. Data synthesis was obtained by using odds ratio (OR) with 95% confidence interval (CI) by a random effects model. An OR <1 favoured GDT. Statistical heterogeneity was assessed by Q and I(2) statistics. Eleven articles (five cardiac surgery and six vascular procedures), enrolling a total sample of 1179 patients, were included in the analysis. As compared with routine haemodynamic practice, perioperative GDT did not reduce mortality in either cardiac or vascular surgery (pooled OR 0.87; 95% CI 0.37-2.02; statistical power 64%). GDT significantly reduced the number of cardiac patients with complications (OR 0.34; 95% CI 0.18-0.63; P = 0.0006), but no effect was observed in vascular patients (OR, 0.84; 95% CI 0.45-1.56; P = 0.58). Perioperative GDT prevents postoperative complications in cardiac surgery patients, while it has no effect in vascular surgery. The different characteristics and comorbidities of the population enrolled could explain these conflicting results. More trials conforming to the characteristics of low-risk-of-bias studies and enrolling a larger and well-defined population of patients are needed to better clarify the effect of GDT in the specific setting of cardiovascular surgery.

Use of inotropes and vasopressor agents in critically ill patients

Inotropes and vasopressors are biologically and clinically important compounds that originate from different pharmacological groups and act at some of the most fundamental receptor and signal transduction systems in the body. More than 20 such agents are in common clinical use, yet few reviews of their pharmacology exist outside of physiology and pharmacology textbooks. Despite widespread use in critically ill patients, understanding of the clinical effects of these drugs in pathological states is poor. The purpose of this article is to describe the pharmacology and clinical applications of inotropic and vasopressor agents in critically ill patients.

Perioperative fluid management strategies in major surgery: a stratified meta-analysis

BACKGROUND

Both "liberal" and "goal-directed" (GD) therapy use a large amount of perioperative fluid, but they appear to have very different effects on perioperative outcomes. We sought to determine whether one fluid management strategy was superior to the others.

METHODS

We selected randomized controlled trials (RCTs) on the use of GD or restrictive versus liberal fluid therapy (LVR) in major adult surgery from MEDLINE, EMBASE, PubMed (1951 to April 2011), and Cochrane controlled trials register without language restrictions. Indirect comparison between the GD and LVR strata was performed.

RESULTS

A total of 3861 patients from 23 GD RCTs (median sample size = 90, interquartile range [IQR] 57 to 109) and 1160 patients from 12 LVR RCTs (median sample size = 80, IQR36 to 151) were considered. Both liberal and GD therapy used more fluid compared to their respective comparative arm, but their effects on outcomes were very different. Patients in the liberal group of the LVR stratum had a higher risk of pneumonia (risk ratio [RR] 2.2, 95% confidence interval [CI] 1.0 to 4.5), pulmonary edema (RR 3.8, 95% CI 1.1 to 13), and a longer hospital stay than those in the restrictive group (mean difference [MD] 2 days, 95% CI 0.5 to 3.4). Using GD therapy also resulted in a lower risk of pneumonia (RR 0.7, 95% CI 0.6 to 0.9) and renal complications (0.7, 95% CI 0.5 to 0.9), and a shorter length of hospital stay (MD 2 days, 95% CI 1 to 3) compared to not using GD therapy. Liberal fluid therapy was associated with an increased length of hospital stay (4 days, 95% CI 3.4 to 4.4), time to first bowel movement (2 days, 95% CI 1.3 to 2.3), and risk of pneumonia (RR ratio 3, 95% CI 1.8 to 4.8) compared to GD therapy.

CONCLUSION

Perioperative outcomes favored a GD therapy rather than liberal fluid therapy without hemodynamic goals. Whether GD therapy is superior to a restrictive fluid strategy remains uncertain.

Swan-Ganz catheter use in trauma patients can be reduced without negatively affecting outcomes

OBJECTIVE

The use of pulmonary artery catheter (PAC) is controversial. The purpose of this study was to document the changing pattern of PAC use and to determine its effect on outcome.

METHODS

The use of PAC was analyzed in patients ≥16 years old admitted to the surgical intensive care unit (SICU) over a 9-year period starting in 2000. Patients with SICU length of stay exceeding 30 days were excluded. For the evaluation of PAC's effect on outcome, PAC and no-PAC patients were matched utilizing propensity scores.

RESULTS

During the 9-year study period, a total of 5,192 trauma patients were admitted to the SICU. Of these, 426 (8.2%) were <16 years old, and 174 (3.4%) had a SICU length of stay that exceeded 30 days. For the remaining 4,592 patients, the mean ± SD age was 39.5 ± 18.8 years, and the mean ISS was 19.9 ± 12.4. PAC was utilized in 19.5% (n = 896) of all the patients admitted to the SICU. The trend for PAC use decreased significantly over the years (P value for trend <0.001), from 38.6% in the year 2000 to 4.2% in the year 2008. This decrease was noted in all age and injury severity groups of patients. The overall mortality, however, remained at the same levels (P value for trend = 0.111). Patients managed with a PAC were significantly older, more severely injured, more frequently injured by a blunt mechanism, and were admitted more often in a hypotensive or comatose status. In the early part of the study, the PAC was utilized on the first day and for 4.1 days on average. In the later part of the study, however, the PAC was used on the second day and for a shorter period of time (3 days on average, P < 0.001). In the matched study population, patients in the PAC group had almost twofold higher odds for death, when compared to the no-PAC group [34.2% vs. 22.5%, Odds Ratio (95% CI): 1.78 (1.42, 2.26), P < 0.001]. Patients younger than 50 years of age who had an ISS ≥16 had worse outcome when managed with a PAC, whereas patients aged 30-69 years with an ISS <16 had a higher survival. The overall complication rate was fivefold higher in patients receiving a PAC [46.3% vs. 14.2%, Odds Ratio (95% CI): 5.22 (4.04, 6.74), P < 0.001].

CONCLUSION

The use of PAC has decreased almost 10-fold over the last decade at our institution. The PAC is being used later during the ICU course and for a shorter period of time. In a matched population, the use of PAC is associated with a significantly higher mortality and complication rate, but the reason for this association remains uncertain. The use of PAC is invasive and is associated with known complications and financial costs. While the use of PAC maybe useful in a select population, routine and widespread use of the PAC should be avoided.

Restrictive strategy of intraoperative fluid maintenance during optimization of oxygen delivery decreases major complications after high-risk surgery

Introduction

Optimal fluid management is crucial for patients who undergo major and prolonged surgery. Persistent hypovolemia is associated with complications, but fluid overload is also harmful. We evaluated the effects of a restrictive versus conventional strategy of crystalloid administration during goal-directed therapy in high-risk surgical patients.

Methods

We conducted a prospective, randomized, controlled study of high-risk patients undergoing major surgery. For fluid maintenance during surgery, the restrictive group received 4 ml/kg/hour and the conventional group received 12 ml/kg/hour of Ringer's lactate solution. A minimally invasive technique (the LiDCO monitoring system) was used to continuously monitor stroke volume and oxygen delivery index (DO₂I) in both groups. Dobutamine was administered as necessary, and fluid challenges were used to test fluid responsiveness to achieve the best possible DO₂I during surgery and for 8 hours postoperatively.

Results

Eighty-eight patients were included. The patients' median age was 69 years. The conventional treatment group received a significantly greater amount of lactated Ringer's solution (mean ± standard deviation (SD): 4, 335 ± 1, 546 ml) than the restrictive group (mean ± SD: 2, 301 ± 1, 064 ml) (P < 0.001). Temporal patterns of DO₂I were similar between the two groups. The restrictive group had a 52% lower rate of major postoperative complications than the conventional group (20.0% vs 41.9%, relative risk = 0.48, 95% confidence interval = 0.24 to 0.94; P = 0.046).

Conclusions

A restrictive strategy of fluid maintenance during optimization of oxygen delivery reduces major complications in older patients with coexistent pathologies who undergo major surgery.

Trial registration

ISRCTN: ISRCTN94984995