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

Outcome Selection and Methodological Quality of Major and Minor Shoulder Surgery Studies: A Scoping Review

BACKGROUND

Core outcome sets aim to select and standardize the choice of important outcomes reported in clinical trials to encourage more effective data synthesis, increase the reliability of comparing results, and minimize reporting bias. A core outcome set for elective shoulder surgery has yet to be defined, and therefore a systematic assessment of outcomes and methodology is necessary to inform the development of a core outcome set.

QUESTIONS/PURPOSES

The purpose of this study was to examine randomized controlled trials (RCTs) of patients having elective major or minor shoulder surgery to (1) identify the outcome domains reported; (2) determine specific outcome measurement tools that were utilized; and (3) assess the work for methodological quality and risk of bias.

METHODS

We conducted a scoping review (a review that identifies the nature and extent of research evidence) to explore the reported outcome domains, outcome tools, and methodological quality from RCTs conducted in shoulder surgery. We considered both major shoulder surgery (defined as arthroplasty, rotator cuff repair, stabilization procedures, biceps tenodesis, or Bankart repairs) and minor shoulder surgery (simple arthroscopy, capsular plication, lateral clavicular excisions, or subacromial decompression). We queried 10 electronic databases for studies published between January 2006 and January 2015. Studies were included if they were prospective, randomized controlled, clinical trials enrolling patients who received an elective shoulder surgical intervention. We extracted data relating to trial characteristics, primary outcomes, tools used to measure these outcomes as well as methodological quality indicators. We assessed indicators of methodological quality by exploring (1) the reproducibility of power analyses; and (2) whether the primary outcomes were powered to minimum clinically important differences. Risk of bias was also assessed with the Jadad score with scores between 0 (very high risk of bias) and 5 (very low risk). Findings were qualitatively analyzed and reported according to systematic and scoping review guidelines. We included 315 studies involving 30,232 patients; 266 studies investigated anesthetic, analgesic, or surgical interventions.

RESULTS

Of the 315 studies included, the most common outcome domains evaluated were analgesic (n = 104), functional (n = 87), anesthetic (n = 56), and radiologic (n = 29) outcomes, with temporal patterns noted. Studies of major shoulder surgery most commonly reported functional primary outcome domains, whereas minor shoulder surgery studies most frequently reported analgesic primary outcome domains. There were 85 different primary outcome tools utilized, which included 20 functional, 20 anesthetic, 13 analgesic, and 12 radiologic. A methodological quality assessment revealed that 24% of studies had reproducible power analyses, 13% were powered to minimum clinically important differences, and risk of bias assessment demonstrated a median (interquartile range [range]) Jadad score of 4 (3-5 [1-5]).

CONCLUSIONS

A wide range of outcome domains and outcome assessment tools are in common use in contemporary trials of patients undergoing elective surgery. Although some diversity is important to allow the assessment of patient populations that may have different goals, the large number of tools in common use may impair the ability of future meta-analyses to pool results effectively or even for systematic reviews to synthesize what is known. The limitations of methodological quality in RCTs may be improved by researchers following standard guidelines and considering the minimum clinically important differences in their trials to be of greater use to clinicians and their patients.

LEVEL OF EVIDENCE

Level I, therapeutic study.

Oesophageal Doppler guided goal-directed haemodynamic therapy in thoracic surgery - a single centre randomized parallel-arm trial

Background

Postoperative pulmonary and renal complications are frequent in patients undergoing lung surgery. Hyper- and hypovolaemia may contribute to these complications. We hypothesized that goal-directed haemodynamic management based on oesophageal Doppler monitoring would reduce postoperative pulmonary complications in a randomized clinical parallel-arm trial.

Methods

One hundred patients scheduled for thoracic surgery were randomly assigned to either standard haemodynamic management (control group) or goal-directed therapy (GDT group) guided by an oesophageal Doppler monitoring-based algorithm. The primary endpoint was postoperative pulmonary complications, including spirometry. Secondary endpoints included haemodynamic variables, renal, cardiac, and neurological complications, and length of hospital stay. The investigator assessing outcomes was blinded to group assignment.

Results

Forty-eight subjects of each group were analysed. Compared to the control group, fewer subjects in the GDT group developed postoperative pulmonary complications (6 vs. 15 patients; P  = 0.047), while spirometry did not differ between groups. Compared to the control group, patients of the GDT group showed higher cardiac index (2.9 vs. 2.1 [l min - 1 m  - 2 ]; P  < 0.001) and stroke volume index (43 vs. 34 [ml m 2 ]; P  < 0.001) during surgery. Renal, cardiac and neurological complications did not differ between groups. Length of hospital stay was shorter in the GDT compared to the control group (9 vs. 11 days; P  = 0.005).

Conclusions

Compared to standard haemodynamic management, oesophageal Doppler monitor-guided GDT was associated with fewer postoperative pulmonary complications and a shorter hospital stay.

Clinical trial registration.

The study was registered in the German Clinical Trials Register (DRKS 00006961). https://drks-neu.uniklinik-freiburg.de/drks_web/.

Clinical and economic impact of goal-directed fluid therapy during elective gastrointestinal surgery

BACKGROUND

Several randomized controlled trials suggest that goal-directed fluid therapy (GDFT) may result in improved postoperative outcomes. The aim of this study was to assess the clinical and financial impact of the real-life implementation of intraoperative GDFT in patients undergoing elective gastrointestinal surgery in a Chinese tertiary medical center.

METHODS

This Quality Improvement Program (QIP) study comprised three phases of 5, 1, and 5 months, respectively. During the first phase, we retrospectively collected perioperative data from patients who received standard intraoperative fluid management from January to May 2016. Then a 1-month training period allowed the clinical staff to become familiar with the GDFT protocol. After the training phase, GDFT was used from July to November 2016. In the GDFT group, stroke volume (SV) was continuously monitored and optimized towards the plateau of the Frank-Starling curve. The primary outcome measure was postoperative morbidity (the proportion of patients with one or more complications within 30 days after surgery). Secondary outcomes were total hospital cost, postoperative length of hospital stay, and 30-day mortality.

RESULTS

Data from 200 patients before (control group) and 201 patients after the implementation of GDFT (GDFT group) were collected and compared. There was no significant difference in demographics and surgical procedures between the two groups. Postoperative morbidity was significantly lower in the GDFT group than in the control group (30.8% vs. 44.0%, p = 0.006). No significant differences were observed for mean total hospital cost (76,793 RMB vs. 74,444 RMB; p = 0.430), median postoperative length of hospital stay (10 days vs. 10 days; p = 0.104), and 30-day mortality (1% vs. 0.5%; p = 0.565).

CONCLUSION

In patients undergoing gastrointestinal surgery, the implementation of a GDFT protocol was associated with a reduction in postoperative morbidity without increasing costs.

TRIAL REGISTRATION

clinicaltrials.gov, NCT02507557. Registered 13 July 2015.

Acute kidney injury following implementation of an enhanced recovery after surgery (ERAS) protocol in colorectal surgery

PURPOSE

Fluid management within Enhanced Recovery After Surgery (ERAS) protocols is designed to maintain a euvolemic state avoiding the negative sequelae of hypervolemia or hypovolemia. We sought to determine the effect of a recent ERAS protocol implementation on kidney function and on the incidence of postoperative acute kidney injury (AKI).

METHODS

A total of 132 elective colorectal resections performed using our ERAS protocol were compared to a propensity-matched group prior to ERAS implementation. Fluid balance, urine output, creatinine, and blood urea nitrogen (BUN) were recorded for all patients, and the incidence of AKI was determined according to the Kidney Disease Improving Global Outcomes (KDIGO) criteria.

RESULTS

Implementation of our ERAS protocol decreased average postoperative length of hospital stay (5.5 vs 7.7 days, p < 0.0001) and time to return of bowel function (2.5 vs 4.1 days, p < 0.0001). The rate of postoperative AKI increased following implementation of the protocol (11.4 vs 2.3%, p < 0.0001). However, by the time of discharge, the average creatinine of ERAS patients who had experienced AKI had returned to their preoperative baseline values (p = 0.9037). Significant univariate predictors of AKI in ERAS patients were longer operative times (p < 0.01) and the diagnosis of diverticulitis (p < 0.01). Within our ERAS patients, AKI was associated with a prolonged postoperative length of hospital stay (p < 0.01).

CONCLUSIONS

Despite the proven benefits of the Enhanced Recovery After Surgery (ERAS) protocols, care should be taken during protocol implementation to monitor for and to prevent acute kidney injury.

Pleth variability index or stroke volume optimization during open abdominal surgery: a randomized controlled trial

Background

The impact of Goal Directed Fluid Therapy (GDFT) based on the non-invasive Pleth Variability Index (PVI) on clinical outcome after abdominal surgery has only sparingly been explored. The purpose of this study was to compare the effect of intraoperative GDFT guided by PVI to a control group using esophageal Doppler on the incidence of complications and length of hospital stay after major abdominal surgery. We hypothesized that there would be no difference between the groups.

Methods

This was a randomized controlled trial in a Swedish university hospital between November 2011 and January 2015; 150 patients scheduled for open abdominal surgery lasting 2 h or more were included. Exclusion criteria included hepatic resection or severe cardiac arrhythmia. The patients were randomized 1:1 to either the intervention group or the control group. The intervention group received intraoperative GDFT by administering fluid boluses of 3 ml/kg tetrastarch aiming at a PVI value below 10%, while GDFT in the control group aimed for optimization of stroke volume as assessed with esophageal Doppler. Blinded observers assessed complications until postoperative day 30 using pre-defined definitions, as well as length of hospital stay.

Results

One hundred and-fifty patients were randomized and 146 patients were available for the final data analysis. Median duration of surgery was 3 h. A total of 64 complications occurred in the PVI group (N = 74) and 70 in the Doppler group (N = 72) (p = 0.93). Median (IQR) length of stay was 8.0 (8.0) days in the PVI group and 8.0 (9.5) in the Doppler group (P = 0.57).

Conclusions

No difference in clinical outcome, as defined by number of postoperative complications, and length of hospital stay, was found when goal directed fluid therapy was applied using PVI as an alternative to esophageal Doppler. PVI appears to be an acceptable alternative to esophageal Doppler for goal directed fluid therapy during major open abdominal surgery.

Trial registration

Clinicaltrials.gov NCT01458678. Date of first registration October 20, 2011.

Electronic supplementary material

The online version of this article (10.1186/s12871-018-0579-4) contains supplementary material, which is available to authorized users.

Evaluation of hemodynamic goal-directed therapy to reduce the incidence of bone cement implantation syndrome in patients undergoing cemented hip arthroplasty - a randomized parallel-arm trial

BACKGROUND

The bone cement implantation syndrome (BCIS) is a frequent and potentially disastrous intraoperative complication in patients undergoing cemented hip arthroplasty. Several risk factors have been identified, however randomized controlled trials to reduce the incidence of BCIS are still pending. We hypothesized that goal-directed hemodynamic therapy guided by esophageal Doppler monitoring (EDM) may reduce the incidence of BCIS in a randomized, controlled parallel-arm trial.

METHODS

After approval of the local ethics committee, 90 patients scheduled for cemented hip arthroplasty at the Medical Center - University of Freiburg were randomly assigned to either standard hemodynamic management or goal-directed therapy (GDT) guided by an esophageal Doppler monitoring-based algorithm. The primary endpoint was the incidence of overall BCIS including grade 1-3 after cementation of the femoral stem. Secondary endpoints included cardiac function, length of hospital stay and postoperative complications.

RESULTS

Ninety patients were finally analyzed. With regards to the primary endpoint, the overall incidence of BCIS showed no difference between the GDT and control group. Compared to the control group, patients of the GDT group showed a higher cardiac index before and after bone cement implantation (2.7 vs. 2.2 [l●min^- 1●m^- 2]; 2.8 vs. 2.4 [l●min^- 1●m^- 2]; P = 0.003, P = 0.042), whereas intraoperative amount of fluids and mean arterial pressure did not differ.

CONCLUSIONS

The implementation of a specific hemodynamic goal-directed therapy did not reduce the overall incidence of BCIS in patients undergoing cemented hip arthroplasty.

TRIAL REGISTRATION

This randomized clinical two-arm parallel study was approved by the local Ethics Committee, Freiburg, Germany [EK 160/15, PI: U. Goebel] and registered in the German Clinical Trials Register ( DRKS No. 00008778 , 16th of June, 2015).

Multi-parametric functional hemodynamic optimization improves postsurgical outcome after intermediate risk open gastrointestinal surgery: a randomized controlled trial

BACKGROUND

Perioperative goal directed therapy (pGDT) using flow monitoring has been associated with improved outcomes. However, its protocols are often based on stroke volume only: as a target for fluid loading, inotropic support and vasopressors (via mathematical coupling of systemic vascular resistance). In this trial, we have tested the multi-parametric pGDT protocol based on esophageal Doppler variables (corrected flow time, peak velocity) in intermediate-to-high risk patients undergoing gastrointestinal surgery.

METHODS

Intermediate-to-high risk patients undergoing gastrointestinal surgery were randomized to standard care (control) or multi-parametric pGDT (intervention). Postoperative complications and death rate as well as hospital length of stay were assessed as primary and secondary outcomes.

RESULTS

Overall, 140 patients (intervention, N.=71, and control, N.=69) were included and randomized out of 197 eligible. Higher vasoactive/inotropic drug use and lower fluid balance were observed in the intervention group leading to favorable hemodynamic profile. The pGDT intervention was associated with improved primary outcome (28 days mortality and morbidity defined as occurrence of any defined complication) - 20 patients (28.2%) versus 32 (46.4%) in the control group (P=0.036); RR 0.61 (95% CI: 0.39-0.95), P=0.03. No differences in mortality and hospital length of stay were observed between groups.

CONCLUSIONS

In this monocentric trial the multi-parametric pGDT protocol based on domain specific functional hemodynamic parameters was associated with lower rate of postoperative complications in intermediate-to-high risk patients undergoing scheduled gastrointestinal procedures.

Individualized, perioperative, hemodynamic goal-directed therapy in major abdominal surgery (iPEGASUS trial): study protocol for a randomized controlled trial

Background

Postoperative morbidity and mortality in patients undergoing surgery is high, especially in patients who are at risk of complications and undergoing major surgery. We hypothesize that perioperative, algorithm-driven, hemodynamic therapy based on individualized fluid status and cardiac output optimization is able to reduce mortality and postoperative moderate and severe complications as a major determinant of the patients’ postoperative quality of life, as well as health care costs.

Methods/design

This is a multi-center, international, prospective, randomized trial in 380 patients undergoing major abdominal surgery including visceral, urological, and gynecological operations. Eligible patients will be randomly allocated to two treatment arms within the participating centers. Patients of the intervention group will be treated perioperatively following a specific hemodynamic therapy algorithm based on pulse-pressure variation (PPV) and individualized optimization of cardiac output assessed by pulse-contour analysis (ProAQT© device; Pulsion Medical Systems, Feldkirchen, Germany). Patients in the control group will be treated according to standard local care based on established basic hemodynamic treatment. The primary endpoint is a composite comprising the occurrence of moderate or severe postoperative complications or death within 28 days post surgery. Secondary endpoints are: (1) the number of moderate and severe postoperative complications in total, per patient and for each individual complication; (2) the occurrence of at least one of these complications on days 1, 3, 5, 7, and 28 in total and for every complication; (3) the days alive and free of mechanical ventilation, vasopressor therapy and renal replacement therapy, length of intensive care unit, and hospital stay at day 7 and day 28; and (4) mortality and quality of life, assessed by the EQ-5D-5L™ questionnaire, after 6 months.

Discussion

This is a large, international randomized controlled study evaluating the effect of perioperative, individualized, algorithm-driven ,hemodynamic optimization on postoperative morbidity and mortality.

Trial registration

Trial registration: NCT03021525. Registered on 12 January 2017.

Electronic supplementary material

The online version of this article (10.1186/s13063-018-2620-9) contains supplementary material, which is available to authorized users.

The evaluation of risk prediction models in predicting outcomes after bariatric surgery: a prospective observational cohort pilot study

Background

As the prevalence of obesity is increasing, the number of patients requiring surgical intervention for obesity-related illness is also rising. The aim of this pilot study was to explore predictors of short-term morbidity and longer-term poor weight loss after bariatric surgery.

Methods

This was a single-centre prospective observational cohort pilot study in patients undergoing bariatric surgery. We assessed the accuracy (discrimination and calibration) of two previously validated risk prediction models (the Physiological and Operative Severity Score for the enumeration of Morbidity and Mortality, POSSUM score, and the Obesity Surgical Mortality Risk Score, OS-MS) for postoperative outcome (postoperative morbidity defined using the Post Operative Morbidity Survey). We then tested the relationship between postoperative morbidity and longer-term weight loss outcome adjusting for known patient risk factors.

Results

Complete data were collected on 197 patients who underwent surgery for obesity or obesity-related illnesses between March 2010 and September 2013. Results showed POSSUM and OS-MRS were less accurate at predicting Post Operative Morbidity Survey (POMS)-defined morbidity on day 3 than defining prolonged length of stay due to poor mobility and/or POMS-defined morbidity. Having fewer than 28 days alive and out of hospital within 30 days of surgery was predictive of poor weight loss at 1 year, independent of POSSUM-defined risk (odds ratio 2.6; 95% confidence interval 1.28-5.24).

Conclusions

POSSUM may be used to predict patients who will have prolonged postoperative LOS after bariatric surgery due to morbidity or poor mobility. However, independent of POSSUM score, having less than 28 days alive and out of hospital predicted poor weight loss outcome at 1 year. This adds to the literature that postoperative complications are independently associated with poor longer-term surgical outcomes.

Cardiac output Optimisation following Liver Transplant (COLT) trial: study protocol for a feasibility randomised controlled trial

Background

Patients with liver cirrhosis undergoing liver transplantation have a hyperdynamic circulation which persists into the early postoperative period making accurate assessment of fluid requirements challenging. Goal-directed fluid therapy (GDFT) has been shown to reduce morbidity and mortality in a number of surgery settings. The impact of GDFT in patients undergoing liver transplantation is unknown. A feasibility trial was designed to determine patient and clinician support for recruitment into a randomised controlled trial of GDFT following liver transplantation, adherence to a GDFT protocol, participant withdrawal, and to determine appropriate endpoints for a subsequent larger trial to evaluate the efficacy of GDFT in patients undergoing liver transplantation.

Methods

The Cardiac output Optimisation following Liver Transplant (COLT) trial is designed as a prospective, single-centre, randomised controlled study to assess the feasibility and safety of GDFT in liver transplantation for patients with cirrhosis. Consenting adults (aged between 18 and 80 years) with biopsy-proven liver cirrhosis who have been selected to undergo a first liver transplantation will be included in the trial and randomised into GDFT or standard care starting immediately after surgery and continuing for the first 12 h thereafter. Both groups will have cardiac output and stroke volume monitored using the FloTrac (EV1000) device. The intervention will consist of a protocolised GDFT approach to patient management, using stroke volume optimisation. The control group will receive standard care, without stroke volume and cardiac output measurement. After 12 h the patient’s fluid management will revert to standard of care. The primary endpoint of this study is feasibility. Secondary endpoints will include a safety assessment of the intervention, graft and patient survival, liver function, postoperative complications graded by Clavien-Dindo criteria, length of intensive care and hospital stay and quality of life across the intervention and control groups.

Discussion

There is a growing body of evidence that the use of perioperative GDFT in surgical patients can improve outcomes; however, signals of harm have also been detected. Patients with liver cirrhosis undergoing liver transplantation have markedly different cardiovascular physiology than general surgical patients. If GDFT is proven to be feasible and safe in this patient group, then a multicentre trial to demonstrate efficacy and cost-effectiveness will be required.

Trial registration

International Standard Randomised Controlled Trial Registry, ID: ISRCTN10329248. Registered on 4 April 2016.

Electronic supplementary material

The online version of this article (10.1186/s13063-018-2488-8) contains supplementary material, which is available to authorized users.

Impact of hypotension and global hypoperfusion in postoperative delirium: a pilot study in older adults undergoing open colon surgery

Background

Post-operative delirium is a serious complication in patients undergoing major abdominal surgery. It remains unclear whether peri-operative hemodynamic and perfusion variables affect the risk for postoperative delirium. The objective of this pilot study was to evaluate the association between perfusion and hemodynamics peri-operative with the appearance of post-operative delirium.

Methods

Prospective cohort study of adults 60 years or older undergoing elective open colon surgery. Multimodal hemodynamic and perfusion variables were monitored, including central venous oxygenation (ScvO₂), lactate levels, and non-invasive cerebral oxygenation (rSO₂), according to a standard anesthesia protocol. Fisher's exact test or Student's t-test were used to compare patients who developed post-operative delirium with those who did not (p < 0.05).

Results

We studied 28 patients, age 73 ± 7 years, 60.7% female. Two patients developed post-operative delirium (7.1%). These two patients had fewer years of education than those without delirium (p = 0.031). None of the peri-operative blood pressure variables were associated with incidence of post-operative delirium. In terms of perfusion parameters, postoperative ScvO₂ was lower in the delirium than the non-delirium group, without reaching statistical significance (65 ± 10% vs. 74 ± 5%; p = 0.08), but the delta-ScvO₂ (the difference between means post-operative and intra-operative) was associated with post-operative delirium (p = 0.043). Post-operative lactate and rSO₂ variables were not associated with delirium.

Conclusions

Our pilot study suggests an association between delta ScvO₂ and post-operative delirium, and a tendency to lower post-operative ScvO₂ in patients who developed delirium. Further studies are necessary to elucidate this association.

Perioperative Goal-Directed Therapy Using Invasive Uncalibrated Pulse Contour Analysis

“Perioperative goal-directed therapy” (PGDT) aims at an optimization of basic and advanced global hemodynamic variables to maintain adequate oxygen delivery to the end-organs. PGDT protocols help to titrate fluids, vasopressors, or inotropes to hemodynamic target values. There is considerable evidence that PGDT can improve patient outcome in high-risk patients if both fluids and inotropes are administered to target hemodynamic variables reflecting blood flow. Despite this evidence, PGDT strategies aiming at an optimization of blood flow seem to be not well implemented in routine clinical care. The analysis of the arterial blood pressure waveform using invasive uncalibrated pulse contour analysis can be used to assess hemodynamic variables used in PGDT protocols. Pulse contour analysis allows the assessment of stroke volume (SV)/cardiac output (CO) and pulse pressure variation (PPV)/stroke volume variation (SVV) and thus helps to titrate fluids and vasoactive agents based on principles of “functional hemodynamic monitoring.” Pulse contour analysis-based PGDT treatment algorithms can be classified according to the hemodynamic variables they use as targets: PPV/SVV, SV/CO, or a combination of these variables. From a physiologic point of view, algorithms using both dynamic cardiac preload and blood flow variables as hemodynamic targets might be most effective in improving patient outcome. Future research should focus on the improvement of hemodynamic treatment algorithms and on the identification of patient subgroups in which PGDT based on uncalibrated pulse contour analysis can improve patient outcome.

Goal-directed therapy reduces fluid balance while maintaining hemodynamic stability in intraoperative management of pancreaticoduodenectomy: a retrospective comparative study

Background

Goal-directed therapy (GDT) is beneficial for surgical patients, especially for those undergoing high-risk surgery. However, little has been reported on the hemodynamic effects of GDT in extensive surgery. We conducted a study to determine the impact of GDT on intraoperative management of extensive surgery.

Findings

We retrospectively collected data from 90 patients who underwent pancreaticoduodenectomy: 44 who received intraoperative GDT (GDT group) and 46 who received conventional hemodynamic management (control group). Intraoperative use of fluids and catecholamines and physiologic variables, including mean arterial pressure, heart rate, and urine output, were compared. We also examined the correlation between the amount of fluid administered and urine output. The amount of fluid administered was comparable, and urine output was significantly larger in the GDT group than in the control group. Fluid balance was significantly smaller in the GDT group (49.7 versus 61.7 mL/kg; 95% confidence interval, − 19.5 to − 4.6 mL/kg; P = 0.0019). There was a trend toward higher mean arterial pressure in the GDT group despite lower fluid balance. We found a rank correlation between the amount of fluid administered and urine output in the GDT group (rank correlation coefficient, 0.68; P < 0.001), but there was no such correlation in the control group.

Conclusions

GDT increased urine output and decreased fluid balance while maintaining hemodynamic stability. The amount of fluid administered and urine output were correlated in the GDT group.

[Impact of hypotension and global hypoperfusion in postoperative delirium: a pilot study in older adults undergoing open colon surgery]

BACKGROUND

Post-operative delirium is a serious complication in patients undergoing major abdominal surgery. It remains unclear whether peri-operative hemodynamic and perfusion variables affect the risk for postoperative delirium. The objective of this pilot study was to evaluate the association between perfusion and hemodynamics peri-operative with the appearance of post-operative delirium.

METHODS

Prospective cohort study of adults 60 years or older undergoing elective open colon surgery. Multimodal hemodynamic and perfusion variables were monitored, including central venous oxygenation (ScvO₂), lactate levels, and non-invasive cerebral oxygenation (rSO₂), according to a standard anesthesia protocol. Fisher's exact test or Student's t-test were used to compare patients who developed post-operative delirium with those who did not (p<0.05).

RESULTS

We studied 28 patients, age 73±7 years, 60.7% female. Two patients developed post-operative delirium (7.1%). These two patients had fewer years of education than those without delirium (p=0.031). None of the peri-operative blood pressure variables were associated with incidence of post-operative delirium. In terms of perfusion parameters, postoperative ScvO₂ was lower in the delirium than the non-delirium group, without reaching statistical significance (65±10% vs. 74±5%; p=0.08), but the delta-ScvO₂ (the difference between means post-operative and intra-operative) was associated with post-operative delirium (p=0.043). Post-operative lactate and rSO₂ variables were not associated with delirium.

CONCLUSIONS

Our pilot study suggests an association between delta ScvO₂ and post-operative delirium, and a tendency to lower post-operative ScvO₂ in patients who developed delirium. Further studies are necessary to elucidate this association.

Contemporary Approaches to Perioperative IV Fluid Therapy

BACKGROUND

Intravenous fluid therapy is required for most surgical patients, but inappropriate regimens are commonly prescribed. The aim of this narrative review was to provide evidence-based guidance on appropriate perioperative fluid management.

METHOD

We did a systematic literature search of the literature to identify relevant studies and meta-analyses to develop recommendations.

RESULTS

Of 275 retrieved articles, we identified 25 articles to inform this review. "Normal" saline (0.9% sodium chloride) is not physiological and can result in sodium overload and hyperchloremic acidosis. Starch colloid solutions are not recommended in surgical patients at-risk of sepsis or renal failure. Most surgical patients can have clear fluids and/or administration of carbohydrate-rich drinks up to 2 h before surgery. An intraoperative goal-directed fluid strategy may reduce postoperative complications and reduce hospital length of stay. Regular postoperative assessment of the patient's fluid status and requirements should include looking for physical signs of dehydration or hypovolemia, or fluid overload. Both hypovolemia and salt and water overload lead to adverse events, complications and prolonged hospital stay. Urine output can be an unreliable indicator of hydration status in the postoperative surgical patient. Excess fluid administration has been linked to acute kidney injury, gastrointestinal dysfunction, and cardiac and pulmonary complications.

CONCLUSION

There is good evidence supporting the avoidance of unnecessary fasting and the value of an individualized perioperative IV fluid regimen, with transition to oral fluids as soon as possible, to help patients recover from major surgery.

Accuracy, Precision, and Trending of 4 Pulse Wave Analysis Techniques in the Postoperative Period

OBJECTIVE

The aim of this study was to analyze the accuracy, precision, and trending ability of the following 4 pulse wave analysis devices to measure continuous cardiac output: PiCCO₂ ([PCCO]; Pulsion Medical System, Munich, Germany); LiDCO_Rapid ([LCCO]; LiDCO Ltd, London, UK); FloTrac/Vigileo ([FCCO]; Edwards Lifesciences, Irvine, CA); and Nexfin ([NCCO]; BMEYE, Amsterdam, The Netherlands).

DESIGN

Prospective, observational clinical study.

SETTING

Intensive care unit of a single-center, teaching hospital.

PARTICIPANTS

The study comprised 22 adult patients after elective coronary artery bypass surgery.

INTERVENTIONS

Three measurement cycles were performed in all patient durings their immediate postoperative intensive care stay before and after fluid loading. Hemodynamic measurements were performed 5 minutes before and immediately after the administration of 500 mL colloidal fluid over 20 minutes.

MEASUREMENTS AND MAIN RESULTS

PCCO, LCCO, FCCO, and NCCO were assessed and compared with cardiac output derived from intermittent transpulmonary thermodilution (ICO). One hundred thirty-two matched sets of data were available for analysis. Bland-Altman analysis using linear mixed effects models with random effects for patient and trial revealed a mean bias ±2 standard deviation (%error) of -0.86 ± 1.41 L/min (34.9%) for PCCO-ICO, -0.26 ± 2.81 L/min (46.3%) for LCCO-ICO, -0.28 ± 2.39 L/min (43.7%) for FCCO-ICO, and -0.93 ± 2.25 L/min (34.6%) for NCCO-ICO. Bland-Altman plots without adjustment for repeated measurements and replicates yielded considerably larger limits of agreement. Trend analysis for all techniques did not meet criteria for acceptable performance.

CONCLUSIONS

All 4 tested devices using pulse wave analysis for measuring cardiac output failed to meet current criteria for meaningful and adequate accuracy, precision, and trending ability in cardiac output monitoring.

Current research priorities in perioperative intensive care medicine

INTRODUCTION

Surgical treatments are offered to more patients than ever before, and increasingly to older patients with chronic disease. High-risk patients frequently require critical care either in the immediate postoperative period or after developing complications. The purpose of this review was to identify and prioritise themes for future research in perioperative intensive care medicine.

METHODS

We undertook a priority setting process (PSP). A panel was convened, drawn from experts representing a wide geographical area, plus a patient representative. The panel was asked to suggest and prioritise key uncertainties and future research questions in the field of perioperative intensive care through a modified Delphi process. Clinical trial registries were searched for on-going research. A proposed "Population, Intervention, Comparator, Outcome" (PICO) structure for each question was provided.

RESULTS

Ten key uncertainties and future areas of research were identified as priorities and ranked. Appropriate intravenous fluid and blood component therapy, use of critical care resources, prevention of delirium and respiratory management featured prominently.

CONCLUSION

Admissions following surgery contribute a substantial proportion of critical care workload. Studies aimed at improving care in this group could have a large impact on patient-centred outcomes and optimum use of healthcare resources. In particular, the optimum use of critical care resources in this group is an area that requires urgent research.

Management of excessive inflammatory response in perioperative period of abdominal surgery

Perioperative excessive inflammation of abdominal surgery is caused by many perioperative factors, with activation of inflammatory cells, abnormal expression of cytokines and inflammatory mediators, and imbalance of proinflammatory and anti-inflammatory network system being the major factors. Since perioperative excessive inflammatory response can lead to a series of pathophysiological processes and even multiple organ dysfunction, it is an important factor to hinder the rehabilitation of patients after abdominal surgery. Therefore, management of excessive inflammatory response can control stress response, inhibit the excessive inflammatory reaction and its adverse reactions, reduce postoperative morbidity and mortality, and protect the function of major organs, thereby speeding up the recovery of patients. However, the understanding of the pathophysiological process and the management of excessive inflammatory response during the perioperative period are currently still in the infancy stage. This article systematically reviews the measures of managing the excessive inflammatory response during the perioperative period of abdominal surgery.

Enhanced recovery pathway in patients undergoing distal pancreatectomy: a case-matched study

BACKGROUND

Enhanced recovery (ER) pathways have improved outcomes across multiple surgical specialties, but reports concerning their application in distal pancreatectomy (DP) are lacking. The aim of this study was to assess compliance with an ER protocol and its impact on short-term outcomes in patients undergoing DP.

METHODS

Prospectively collected data were reviewed. One hundred consecutive patients undergoing DP were treated within an ER pathway comprising 18 care elements. Each patient was matched 1:1 with a patient treated with usual perioperative care. Match criteria were age, BMI, ASA score, lesion site, and type of disease.

RESULTS

Adherence to ER items ranged from 15% for intraoperative restrictive fluids to 100% for intraoperative warming, antibiotic and anti-thrombotic prophylaxis. Patients in ER group experienced earlier recovery of gastrointestinal function (2 vs. 3 days, p < 0.001), oral intake (2 vs. 4 days, p < 0.001), and suspension of intravenous infusions (3 vs. 5 days, p < 0.001). Overall morbidity was similar in the two groups (72% vs. 78%). Length of hospital stay (LOS) was reduced in ER patients without postoperative complications (6.7 ± 1.2 vs. 7.6 ± 1.6 days, p = 0.041).

CONCLUSIONS

An ER pathway for DP yielded an earlier postoperative recovery and shortened LOS in uneventful patients. Postoperative morbidity and readmissions were similar in both groups.

Goal-directed fluid restriction during brain surgery: a prospective randomized controlled trial

Background

The value of goal-directed fluid therapy in neurosurgical patients, where brain swelling is a major concern, is unknown. The aim of our study was to evaluate the effect of an intraoperative goal-directed fluid restriction (GDFR) strategy on the postoperative outcome of high-risk patients undergoing brain surgery.

Methods

High-risk patients undergoing brain surgery were randomly assigned to a usual care group (control group) or a GDFR group. In the GDFR group, (1) fluid maintenance was restricted to 3 ml/kg/h of a crystalloid solution and (2) colloid boluses were allowed only in case of hypotension associated with a low cardiac index and a high stroke volume variation. The primary outcome variable was ICU length of stay, and secondary outcomes were lactates at the end of surgery, postoperative complications, hospital length of stay, mortality at day 30, and costs.

Results

A total of 73 patients from the GDFR group were compared with 72 patients from the control group. Before surgery, the two groups were comparable. During surgery, the GDFR group received less colloid (1.9 ± 1.1 vs. 3.9 ± 1.6 ml/kg/h, p = 0.021) and less crystalloid (3 ± 0 vs. 5.0 ± 2.8 ml/kg/h, p < 0.001) than the control group. ICU length of stay was shorter (3 days [1–5] vs. 6 days [3–11], p = 0.001) and ICU costs were lower in the GDFR group. The total number of complications (46 vs. 99, p = 0.043) and the proportion of patients who developed one or more complications (19.2 vs. 34.7%, p = 0.034) were smaller in the GDFR group. Hospital length of stay and costs, as well as mortality at 30 day, were not significantly reduced.

Conclusion

In high-risk patients undergoing brain surgery, intraoperative GDFR was associated with a reduction in ICU length of stay and costs, and a decrease in postoperative morbidity.

Trial registration Chinese Clinical Trial Registry ChiCTR-TRC-13003583, Registered 20 Aug, 2013

Postoperative complications and clinical outcomes among patients undergoing thoracic and gastrointestinal cancer surgery: A prospective cohort study

Objective

This study sought to determine the influence of postoperative complications on the clinical outcomes of patients who underwent thoracic and gastrointestinal cancer surgery.

Methods

A prospective cohort study was conducted regarding 179 consecutive patients who received thorax or digestive tract surgery due to cancer and were admitted to an oncological intensive care unit. The Postoperative Morbidity Survey was used to evaluate the incidence of postoperative complications. The influence of postoperative complications on both mortality and length of hospital stay were also assessed.

Results

Postoperative complications were found for 54 patients (30.2%); the most common complications were respiratory problems (14.5%), pain (12.9%), cardiovascular problems (11.7%), infectious disease (11.2%), and surgical wounds (10.1%). A multivariate logistic regression found that respiratory complications (OR = 18.68; 95%CI = 5.59 - 62.39; p < 0.0001), cardiovascular problems (OR = 5.06, 95%CI = 1.49 - 17.13; p = 0.009), gastrointestinal problems (OR = 26.09; 95%CI = 6.80 - 100.16; p < 0.0001), infectious diseases (OR = 20.55; 95%CI = 5.99 - 70.56; p < 0.0001) and renal complications (OR = 18.27; 95%CI = 3.88 - 83.35; p < 0.0001) were independently associated with hospital mortality. The occurrence of at least one complication increased the likelihood of remaining hospitalized (log-rank test, p = 0.002).

Conclusions

Postoperative complications are frequent disorders that are associated with poor clinical outcomes; thus, structural and procedural changes should be implemented to reduce postoperative morbidity and mortality.

Multidisciplinary perioperative protocol in patients undergoing acute high-risk abdominal surgery

Background

Acute high-risk abdominal (AHA) surgery carries a very high risk of morbidity and mortality and represents a massive healthcare burden. The aim of the present study was to evaluate the effect of a standardized multidisciplinary perioperative protocol in patients undergoing AHA surgery.

Methods

The AHA study was a prospective single-centre controlled study in consecutive patients undergoing AHA surgery, defined as major abdominal pathology requiring emergency laparotomy or laparoscopy including reoperations after elective gastrointestinal surgery. Consecutive patients were included after initiation of the AHA protocol as standard care. The intervention cohort was compared with a predefined, consecutive historical cohort of patients from the same department. The protocol involved continuous staff education, consultant-led attention and care, early resuscitation and high-dose antibiotics, surgery within 6 h, perioperative stroke volume-guided haemodynamic optimization, intermediate level of care for the first 24 h after surgery, standardized analgesic treatment, early postoperative ambulation and early enteral nutrition. The primary outcome was 30-day mortality.

Results

Six hundred patients were included in the study and compared with 600 historical controls. The unadjusted 30-day mortality rate was 21·8 per cent in the control cohort compared with 15·5 per cent in the intervention cohort (P = 0·005). The 180-day mortality rates were 29·5 and 22·2 per cent respectively (P = 0·004).

Conclusion

The introduction of a multidisciplinary perioperative protocol was associated with a significant reduction in postoperative mortality in patients undergoing AHA surgery. NCT01899885 (http://www.clinicaltrials.gov).

Beat-by-beat assessment of cardiac afterload using descending aortic velocity-pressure loop during general anesthesia: a pilot study

INTRODUCTION

Continuous cardiac afterload evaluation could represent a useful tool during general anesthesia (GA) to titrate vasopressor effect. Using beat to beat descending aortic pressure(P)/flow velocity(U) loop obtained from esophageal Doppler and femoral pressure signals might allow to track afterload changes. Methods We defined three angles characterizing the PU loop (alpha, beta and Global After-Load Angle (GALA)). Augmentation index (AIx) and total arterial compliance (Ctot) were measured via radial tonometry. Peripheral Vascular Resistances (PVR) were also calculated. Twenty patients were recruited and classified into low and high cardiovascular (CV) risk group. Vasopressors were administered, when baseline mean arterial pressure (MAP) fell by 20%. Results We studied 118 pairs of pre/post bolus measurements. At baseline, patients in the lower CV risk group had higher cardiac output (6.1 ± 1.7 vs 4.2 ± 0.6 L min; p = 0.005), higher Ctot (2.7 ± 1.0 vs 2.0 ± 0.4 ml/mmHg, p = 0.033), lower AIx and PVR (13 ± 10 vs 32 ± 11% and 1011 ± 318 vs 1390 ± 327 dyn s/cm⁵; p < 0.001 and p = 0.016, respectively) and lower GALA (41 ± 15 vs 68 ± 6°; p < 0.001). GALA was the only PU Loop parameter associated with Ctot, AIx and PVR. After vasopressors, MAP increase was associated with a decrease in Ctot, an increase in AIx and PVR and an increase in alpha, beta and GALA (p < 0.001 for all). Changes in GALA and Ctot after vasopressors were strongly associated (p = 0.004). Conclusions PU Loop assessment from routine invasive hemodynamic optimization management during GA and especially GALA parameter could monitor cardiac afterload continuously in anesthetized patients, and may help clinicians to titrate vasopressor therapy.

Acute kidney injury in the perioperative period and in intensive care units (excluding renal replacement therapies)

Acute kidney injury (AKI) is a syndrome that has progressed a great deal over the last 20 years. The decrease in urine output and the increase in classical renal biomarkers, such as blood urea nitrogen and serum creatinine, have largely been used as surrogate markers for decreased glomerular filtration rate (GFR), which defines AKI. However, using such markers of GFR as criteria for diagnosing AKI has several limits including the difficult diagnosis of non-organic AKI, also called "functional renal insufficiency" or "pre-renal insufficiency". This situation is characterized by an oliguria and an increase in creatininemia as a consequence of a reduction in renal blood flow related to systemic haemodynamic abnormalities. In this situation, "renal insufficiency" seems rather inappropriate as kidney function is not impaired. On the contrary, the kidney delivers an appropriate response aiming to recover optimal systemic physiological haemodynamic conditions. Considering the kidney as insufficient is erroneous because this suggests that it does not work correctly, whereas the opposite is occurring, because the kidney is healthy even in a threatening situation. With current definitions of AKI, normalization of volaemia is needed before defining AKI in order to avoid this pitfall.

Pharmacologic agents for acute hemodynamic instability: recent advances in the management of perioperative shock- a systematic review

Despite the growing body of evidence evaluating the efficacy of vasoactive agents in the management of hemodynamic instability and circulatory shock, it appears no agent is superior. This is becoming increasingly accepted as current guidelines are moving away from detailed algorithms for the management of shock, and instead succinctly state that vasoactive agents should be individualized and guided by invasive hemodynamic monitoring. This extends to the perioperative period, where vasoactive agent selection and use may still be left to the discretion of the treating physician with a goal-directed approach, consisting of close hemodynamic monitoring and administration of the lowest effective dose to achieve the hemodynamic goals. Successful therapy depends on the ability to rapidly diagnose the etiology of circulatory shock and thoroughly understand its pathophysiology as well as the pharmacology of vasoactive agents. This review focuses on the physiology and resuscitation goals in perioperative shock, as well as the pharmacology and recent advances in vasoactive agent use in its management.

Autocalibrating pulse contour analysis based on radial artery applanation tonometry for continuous non-invasive cardiac output monitoring in intensive care unit patients after major gastrointestinal surgery--a prospective method comparison study

The T-Line(®) system (Tensys(®) Medical Inc., San Diego, CA, USA) non-invasively estimates cardiac output (CO) using autocalibrating pulse contour analysis of the radial artery applanation tonometry-derived arterial waveform. We compared T-Line CO measurements (TL-CO) with invasively obtained CO measurements using transpulmonary thermodilution (TDCO) and calibrated pulse contour analysis (PC-CO) in patients after major gastrointestinal surgery. We compared 1) TL-CO versus TD-CO and 2) TL-CO versus PC-CO in 27 patients treated in the intensive care unit (ICU) after major gastrointestinal surgery. For the assessment of TD-CO and PC-CO we used the PiCCO(®) system (Pulsion Medical Systems SE, Feldkirchen, Germany). Per patient, we compared two sets of TD-CO and 30 minutes of PC-CO measurements with the simultaneously recorded TL-CO values using Bland-Altman analysis. The mean of differences (± standard deviation; 95% limits of agreement) between TL-CO and TD-CO was -0.8 (±1.6; -4.0 to +2.3) l/minute with a percentage error of 45%. For TL-CO versus PC-CO, we observed a mean of differences of -0.4 (±1.5; -3.4 to +2.5) l/minute with a percentage error of 43%. In ICU patients after major gastrointestinal surgery, continuous non-invasive CO measurement based on autocalibrating pulse contour analysis of the radial artery applanation tonometry-derived arterial waveform (TL-CO) is feasible in a clinical study setting. However, the agreement of TL-CO with TD-CO and PC-CO observed in our study indicates that further improvements are needed before the technology can be recommended for clinical use in these patients.

A comparison of the non-invasive ultrasonic cardiac output monitor (USCOM) with the oesophageal Doppler monitor during major abdominal surgery

BACKGROUND

Perioperative interventions, targeted to increase global blood flow defined by explicit measured goals, reduce postoperative complications. Consequently, reliable non-invasive estimation of the cardiac output could have far-reaching benefit.

METHODS

This study compared a non-invasive Doppler device - the ultrasonic cardiac output monitor (USCOM) - with the oesophageal Doppler monitor (ODM), on 25 patients during major abdominal surgery. Stroke volume was determined by USCOM (SV_USCOM) and ODM (SV_ODM) pre and post fluid challenges.

RESULTS

A ≥ 10% change (Δ) SV_USCOM had a sensitivity of 94% and specificity of 88% to detect a ≥ 10% Δ SV_ODM; the area under the receiver operating curve was 0.94 (95% CI 0.90-0.99). Concordance was 98%, using an exclusion zone of <10% Δ SV_ODM. 135 measurements gave median SV_USCOM 80 ml (interquartile range 65-93 ml) and SV_ODM 86 ml (69-100 ml); mean bias was 5.9 ml (limits of agreement -20 to +30 ml) and percentage error 30%.

CONCLUSIONS

Following fluid challenges SV_USCOM showed good concordance and accurately discriminated a change ≥10% in SV_ODM.

Comparison between respiratory changes in the inferior vena cava diameter and pulse pressure variation to predict fluid responsiveness in postoperative patients

PURPOSE

The objective of our study was to assess the reliability of the distensibility index of the inferior vena cava (dIVC) as a predictor of fluid responsiveness in postoperative, mechanically ventilated patients and compare its accuracy with that of the pulse pressure variation (PPV) measurement.

MATERIALS AND METHODS

We included postoperative mechanically ventilated and sedated patients who underwent volume expansion with 500mL of crystalloids over 15minutes. A response to fluid infusion was defined as a 15% increase in the left ventricular outflow tract velocity time integral according to transthoracic echocardiography. The inferior vena cava diameters were recorded by a subcostal view using the M-mode and the PPV by automatic calculation. The receiver operating characteristic (ROC) curves were generated for the baseline dIVC and PPV.

RESULTS

Twenty patients were included. The area under the ROC curve for dIVC was 0.84 (95% confidence interval, 0.63-1.0), and the best cutoff value was 16% (sensitivity, 67%; specificity, 100%). The area under the ROC curve for PPV was 0.92 (95% confidence interval, 0.76-1.0), and the best cutoff was 12.4% (sensitivity, 89%; specificity, 100%). A noninferiority test showed that dIVC cannot replace PPV to predict fluid responsiveness (P=.28).

CONCLUSION

The individual PPV discriminative properties for predicting fluid responsiveness in postoperative patients seemed superior to those of dIVC.

Enhanced Recovery After Surgery (ERAS) for gastrointestinal surgery, part 2: consensus statement for anaesthesia practice

Background

The present interdisciplinary consensus review proposes clinical considerations and recommendations for anaesthetic practice in patients undergoing gastrointestinal surgery with an Enhanced Recovery after Surgery (ERAS) programme.

Methods

Studies were selected with particular attention being paid to meta‐analyses, randomized controlled trials and large prospective cohort studies. For each item of the perioperative treatment pathway, available English‐language literature was examined and reviewed. The group reached a consensus recommendation after critical appraisal of the literature.

Results

This consensus statement demonstrates that anaesthesiologists control several preoperative, intraoperative and postoperative ERAS elements. Further research is needed to verify the strength of these recommendations.

Conclusions

Based on the evidence available for each element of perioperative care pathways, the Enhanced Recovery After Surgery (ERAS ^®) Society presents a comprehensive consensus review, clinical considerations and recommendations for anaesthesia care in patients undergoing gastrointestinal surgery within an ERAS programme. This unified protocol facilitates involvement of anaesthesiologists in the implementation of the ERAS programmes and allows for comparison between centres and it eventually might facilitate the design of multi‐institutional prospective and adequately powered randomized trials.

Which intravenous fluid for the surgical patient?

PURPOSE OF REVIEW

This review appraises recent evidence and provides clinical guidance on optimal perioperative fluid therapy.

RECENT FINDINGS

Choice of perioperative intravenous fluid continues to be the source of much debate. Not all crystalloids are equivalent, and there is growing evidence that balanced solutions are superior to 0.9% saline in many situations. Recent evidence from the critical care population has highlighted risks associated with synthetic colloids; this and the absence of demonstrable benefit in the surgical population make it difficult to recommend their use in the perioperative period. Giving the correct amount of fluid may be as important as the choice of the fluid used. There is increasing evidence that excessive positive fluid balance is harmful to patients but there have been no randomized trials comparing maintenance fluid strategy. A knowledge of the physiology and accurate estimation of fluid balance is important for water and electrolyte homeostasis until the patient is able to resume adequate enteral nutrition.

SUMMARY

Balanced crystalloids are the fluid of choice for perioperative resuscitation and optimization in patients not requiring blood products. Avoidance of a grossly positive sodium and water balance during the maintenance phase is likely to be important, but has not been assessed in randomized trials.