Restrictive versus liberal fluid therapy in major abdominal surgery (RELIEF): rationale and design for a multicentre randomised trial

Joint models inform the longitudinal assessment of patient-reported outcomes in clinical trials: a simulation study and secondary analysis of the restrictive Vs. liberal fluid therapy for major abdominal surgery (RELIEF) randomized controlled trial

OBJECTIVES

Evaluate the utility of a joint model when analysing a patient-reported endpoint as part of a randomized controlled trial (RCT) in which censoring occurs when patients die during follow-up.

STUDY DESIGN AND SETTING

The present study comprises two parts as follows: first we reanalyzed data from a previously published RCT comparing two fluid regimens in the first 24 hours of major abdomino-pelvic surgery ('Restrictive versus Liberal Fluid Therapy for Major Abdominal Surgery [RELIEF]' trial). In this trial, patient-reported disability was measured at multiple timepoints before and after surgery. Next, we conducted a simulation study to jointly emulate patient-reported disability and survival, similar to the RELIEF trial, under nine treatment-outcome scenarios. In both parts, we compared a joint model analysis to a linear mixed-effect model combined with one of the several traditional methods of handling longitudinal missingness as follows: available data analysis, complete case analysis, last observation carried forward, and worst-case assumption.

RESULTS

In part one, the joint model revealed no between-group differences in patient-reported disability at 1, 3, 6, and 12 months after surgery. The worst-case approach consistently resulted in the largest deviation from the joint model estimates, although in this particular setting none of the approaches materially changed the study's conclusions. In part two, the simulations revealed that across all treatment-outcome scenarios, the joint model expectedly produced unbiased estimates of patient-reported disability. Similarly, employing an approach based on all available data (ie, relying on the maximum likelihood estimator for handling missingness) yielded disability estimates close to the simulated values, albeit with slight bias across some scenarios. The last observation carried forward approach that mirrored the joint model's estimates except when the treatment had a nonnull effect on patient-reported disability. The worst-case analysis resulted in high bias, which was particularly evident when the treatment had a large effect on survival. The complete case analysis resulted in high bias across all scenarios.

CONCLUSION

In randomized trials that employ a patient-reported outcome as one of their endpoints, a joint model can address bias arising from informative missingness related to death. Methods for handling missingness based on all available data appear to be a reasonable alternative to joint models, with only slight bias across some simulated scenarios.

PLAIN LANGUAGE SUMMARY

'Patient-centered research' focuses on outcomes that are prioritized by patients. This approach often involves asking patients to complete questionnaires about their health experiences. However, if a patient does not finish a study, dealing with their missing answers can pose significant challenges. Joint models are a recent statistical method that may help address this issue. In this study, we used joint models in a real-world clinical trial, and in a series of simulated trials, to determine how well they handle missing questionnaire data from patients. We found that joint models offer significant benefits over most traditional methods used to analyze clinical trials.

Evaluation of the effect of fluid management on intracranial pressure in patients undergoing laparoscopic gynaecological surgery based on the ratio of the optic nerve sheath diameter to the eyeball transverse diameter as measured by ultrasound: a randomised controlled trial

BACKGROUND

During gynecological laparoscopic surgery, pneumoperitoneum and the Trendelenburg position (TP) can lead to increased intracranial pressure (ICP). However, it remains unclear whether perioperative fluid therapy impacts ICP. The purpose of this research was to evaluate the impact of restrictive fluid (RF) therapy versus conventional fluid (CF) therapy on ICP in gynecological laparoscopic surgery patients by measuring the ratio of the optic nerve sheath diameter (ONSD) to the eyeball transverse diameter (ETD) using ultrasound.

METHODS

Sixty-four patients who were scheduled for laparoscopic gynecological surgery were randomly assigned to the CF group or the RF group. The main outcomes were differences in the ONSD/ETD ratios between the groups at predetermined time points. The secondary outcomes were intraoperative circulatory parameters (including mean arterial pressure, heart rate, and urine volume changes) and postoperative recovery indicators (including extubation time, length of post-anaesthesia care unit stay, postoperative complications, and length of hospital stay).

RESULTS

There were no statistically significant differences in the ONSD/ETD ratio and the ONSD over time between the two groups (all p > 0.05). From T2 to T4, the ONSD/ETD ratio and the ONSD in both groups were higher than T1 (all p < 0.001). From T1 to T2, the ONSD/ETD ratio in both groups increased by 14.3%. However, the extubation time in the RF group was shorter than in the CF group [median difference (95% CI) -11(-21 to -2) min, p = 0.027]. There were no differences in the other secondary outcomes.

CONCLUSION

In patients undergoing laparoscopic gynecological surgery, RF did not significantly lower the ONSD/ETD ratio but did shorten the tracheal extubation time, when compared to CF.

TRIAL REGISTRATION

ChiCTR2300079284. Registered on December 29, 2023.

The effect of restrictive compared to liberal intravenous fluid volume on hypotension in adults undergoing major abdominal surgery

In a cardiac output (CO) sub-study of the Restrictive versus Liberal Fluid Therapy in Major Abdominal Surgery (RELIEF) trial, it was shown that restrictive fluid management was associated with lower cardiac index at the end of surgery. However, the association of the fluid protocol with intraoperative blood pressure was less clear. This paper primarily compares rates of hypotension between the two fluid regimens. The haemodynamic effects of these protocols may increase our understanding of perioperative fluid prescription. Using a data set of arterial pressure and cardiac output measurements, this observational cohort study primarily compares intraoperative hypotension rates defined by a mean arterial pressure < 65 mmHg between liberal and restrictive fluid protocols. Secondary analyses explore predictors of invasive mean arterial pressure and doppler-derived cardiac output, including fluid volume regimens and surgical duration. 105 patients had a combined total of 835 haemodynamic data capture events from the beginning to the end of the surgery. Here we report that a restrictive regimen is not associated with a greater proportion of participants who experience at least one episode of hypotension than the liberal regimen 64.1% vs. 61.5% (mean difference 2.6%, 95% CI - 15.9% to 21%, p = 0.78). Duration of surgery was associated with an increased risk of hypotension (OR 1.05, 1 to 1.1, p = 0.038). A fluid restriction protocol compared to liberal fluid administration is not associated with lower blood pressure.

Candidate Kidney Protective Strategies for Patients Undergoing Major Abdominal Surgery: A Secondary Analysis of the RELIEF Trial Cohort

BACKGROUND

Acute kidney injury (AKI) is common after major abdominal surgery. Selection of candidate kidney protective strategies for testing in large trials should be based on robust preliminary evidence.

METHODS

A secondary analysis of the Restrictive versus Liberal Fluid Therapy in Major Abdominal Surgery (RELIEF) trial was conducted in adult patients undergoing major abdominal surgery and randomly assigned to a restrictive or liberal perioperative fluid regimen. The primary outcome was maximum AKI stage before hospital discharge. Two multivariable ordinal regression models were developed to test the primary hypothesis that modifiable risk factors associated with increased maximum stage of postoperative AKI could be identified. Each model used a separate approach to variable selection to assess the sensitivity of the findings to modeling approach. For model 1, variable selection was informed by investigator opinion; for model 2, the Least Absolute Shrinkage and Selection Operator (LASSO) technique was used to develop a data-driven model from available variables.

RESULTS

Of 2,444 patients analyzed, stage 1, 2, and 3 AKI occurred in 223 (9.1%), 59 (2.4%), and 36 (1.5%) patients, respectively. In multivariable modeling by model 1, administration of a nonsteroidal anti-inflammatory drug or cyclooxygenase-2 inhibitor, intraoperatively only (odds ratio, 1.77 [99% CI, 1.11 to 2.82]), and preoperative day-of-surgery administration of an angiotensin-converting enzyme inhibitor or angiotensin receptor blocker compared to no regular use (odds ratio, 1.84 [99% CI, 1.15 to 2.94]) were associated with increased odds for greater maximum stage AKI. These results were unchanged in model 2, with the additional finding of an inverse association between nadir hemoglobin concentration on postoperative day 1 and greater maximum stage AKI.

CONCLUSIONS

Avoiding intraoperative nonsteroidal anti-inflammatory drugs or cyclooxygenase-2 inhibitors is a potential strategy to mitigate the risk for postoperative AKI. The findings strengthen the rationale for a clinical trial comprehensively testing the risk-benefit ratio of these drugs in the perioperative period.

EDITOR’S PERSPECTIVE

The effect of an intraoperative patient-specific, surgery-specific haemodynamic algorithm in improving textbook outcomes for hepatobiliary-pancreatic surgery: a multicentre retrospective study

BACKGROUND

The concept of a "textbook outcome" is emerging as a metric for ideal surgical outcomes. We aimed to evaluate the impact of an advanced haemodynamic monitoring (AHDM) algorithm on achieving a textbook outcome in patients undergoing hepatobiliary-pancreatic surgery.

METHODS

This retrospective, multicentre observational study was conducted across private and public teaching sectors in Victoria, Australia. We studied patients managed by a patient-specific, surgery-specific haemodynamic algorithm or via usual care. The primary outcome was the effect of using a patient-specific, surgery-specific AHDM algorithm for achieving a textbook outcome, with adjustment using propensity score matching. The textbook outcome criteria were defined according to the International Expert Delphi Consensus on Defining Textbook Outcome in Liver Surgery and Nationwide Analysis of a Novel Quality Measure in Pancreatic Surgery.

RESULTS

Of the 780 weighted cases, 477 (61.2%, 95% CI: 57.7%-64.6%) achieved the textbook outcome. Patients in the AHDM group had a higher rate of textbook outcomes [n = 259 (67.8%)] than those in the Usual care group [n = 218 (54.8%); p < 0.001, estimated odds ratio (95% CI) 1.74 (1.30-2.33)]. The AHDM group had a lower rate of surgery-specific complications, severe complications, and a shorter hospital length of stay (LOS) [OR 2.34 (95% CI: 1.30-4.21), 1.79 (95% CI: 1.12-2.85), and 1.83 (95% CI: 1.35-2.46), respectively]. There was no significant difference between the groups for hospital readmission and mortality.

CONCLUSIONS

AHDM use was associated with improved outcomes, supporting its integration in hepatobiliary-pancreatic surgery. Prospective trials are warranted to further evaluate the impact of this AHDM algorithm on achieving a textbook impact on long-term outcomes.

Cytoreductive surgery with hyperthermic intraperitoneal chemotherapy: Effects of postoperative fluids beyond the first 24 h

BACKGROUND AND OBJECTIVES

There are no guidelines for intravenous fluid (IVF) administration after cytoreductive surgery and hyperthermic intraperitoneal chemotherapy (CRS/HIPEC). This study assessed rates of post-CRS/HIPEC morbidity according to perioperative IVF administration.

METHODS

All patients undergoing CRS/HIPEC March 2007 to June 2018 were reviewed, recording clinicopathologic, operative, and postoperative variables. Patients were divided by peritoneal cancer index (PCI), comparing IVF volumes and types administered intraoperatively and during the first 72 h postoperatively. Optimal IVF rate cutoffs calculated using area under the receiver operating characteristic curves and Youden's index determined associations with complications.

RESULTS

Overall, 185 patients underwent CRS/HIPEC, and 81 (51%) had low PCI (<10) and 77 (49%) had high PCI (≥10). In low-PCI patients, high IVF rates on postoperative days (POD) #0-2 were associated with higher overall complications: POD#0 (46% vs. 89%, p = 0.001), POD#1 (40% vs. 86%, p < 0.05), and POD#2 (42% vs. 72%, p < 0.05). High IVF rates were associated with respiratory distress (7% vs. 26%, p = 0.02) on POD#0, ileus (14% vs. 47%, p = 0.007) and intensive care unit stay (11% vs. 33%, p = 0.022) on POD#1, and ICU stay (8% vs. 33%, p = 0.003) on POD#2.

CONCLUSIONS

For low PCI patients undergoing CRS/HIPEC, higher IVF rates were associated with postoperative complications. Post-CRS/HIPEC, IVF rates should be limited to prevent morbidity.

Effects of preoperative nutritional status on disability-free survival after cardiac and thoracic aortic surgery: a prospective observational study

PURPOSE

Preoperative malnutrition is associated with postoperative complications, prolonged intensive care unit stay, and mortality, leading to functional disability after non-cardiac surgery. However, its effects on cardiac and thoracic aortic surgery outcomes remain unknown. We examined the effects of preoperative malnutrition on disability-free survival after surgery and assessed the perioperative 12-item World Health Organization Disability Assessment Schedule 2.0 (WHODAS2.0) score based on the preoperative nutritional status.

METHODS

We included individuals aged ≥ 55 years who underwent elective cardiac and/or thoracic aortic surgery between April 1, 2016 and December 28, 2018 in a tertiary center. The nutritional status was assessed preoperatively using the Mini Nutritional Assessment Short Form, with scores < 12 points indicating a poor nutritional status. The JapanSCORE2 was calculated for surgical risk prediction. Our primary outcome was disability-free survival 1 year after surgery (WHODAS2.0 score: < 16%). The odds ratio of poor nutritional status for disability-free survival was calculated using multiple logistic regression analysis after adjusting for age, JapanSCORE2, and duration of surgery.

RESULTS

One hundred patients were followed up for 1 year. Preoperatively, 41 of them had a poor nutritional status. The disability-free survival rates 1 year postoperatively were 46.3% (19/41) and 64.4% (38/59) in patients with and without poor preoperative nutritional status, respectively. The adjusted odds ratio of poor nutritional status for disability-free survival at 1 year after surgery was 0.42 (95% confidence interval, 0.17-0.99).

CONCLUSION

Patients with a poor preoperative nutritional status had less likely to show disability-free survival 1 year after cardiac and thoracic aortic surgery.

The effects of bicarbonated versus acetated Ringer's solutions on acid-base status and kidney injury following orthotopic liver transplantation: Protocol for a single-centre, randomised controlled trial (The BETTER trial)

BACKGROUND

The ideal crystalloid fluid of choice for fluid therapy during liver transplantation is unknown. Conventional balanced crystalloids are buffered with organic anions, which requires liver metabolism to prevent matabolic acidosis and protect renal function. Therefore they can not function properly during liver transplantation. On the contrary, the bicarbonated Ringer's solution (BRS) can maintain acid-base status regardless of liver function. In this study, we aimed to test the hypothesis that, in patients undergoing orthotopic liver transplantation, compared with acetated Ringer's solutions (ARS), perioperative fluid therapy with BRS could better maintain the acid-base status.

METHODS

This is a prospective, single-centre, randomised controlled trial. 72 eligible patients will be randomised to receive either BRS or ARS perioperatively. The primary endpoint is the difference in standard base excess (SBE) before and after operation. Secondary endpoints include the incidence of acute kidney injury (AKI) within 48 h post operation and free and alive days to day 14 for intensive care admission, invasive ventilation, vasopressors, and renal replacement therapy (RRT).

DISCUSSION

Metabolic acidosis is common perioperatively, potentially leading to decreased renal blood flow and reduced glomerular filtration rate. The use of balanced solutions can prevent hyperchloremic metabolic acidosis, thereby avoiding AKI in some patients. However, during liver transplantation, when well-functioning liver metabolism is lacking, the organic anions in conventional balanced solutions may remain strong anions and thus fail to maintain the acid-base status, but no solid clinical evidence exists now. This study will, for the first time, provide evidence on the relative effects of BRS vs. ARS on acid-base status and renal injury in patients undergoing liver transplantation.

CLINICAL TRIAL REGISTRATION

The trial has been registered at the Chinese Clinical Trials Registry (ChiCTR2100046889) on 29 May 2021.

A Single-Center Retrospective Study of Selected Clinical Parameters and Intraoperative Fluid Management of Patients Undergoing Pancreatoduodenectomy

BACKGROUND Pancreatoduodenectomy is an extensive procedure with a very high risk of complications. Appropriate intraoperative fluid therapy is a subject of ongoing debate. The aim of this retrospective study was to analyze the relationship between selected preoperative parameters, intraoperative fluid therapy, and catecholamines administration during pancreatoduodenectomy. MATERIAL AND METHODS From 2011 through 2017, among pancreatoduodenectomies performed at a single university hospital, 192 patients met the inclusion criteria of the study: 105 (54.7%) males and 87 (45.3%) females with a mean age of 60.06 (±11.63) years. Correlations were assessed between sex, age, body mass index (BMI), selected comorbidities, surgery duration, American Society of Anesthesiologists (ASA) Physical Status (PS) scale, preoperative endoscopic retrograde cholangiopancreatography (ERCP) and intraoperative catecholamine administration, intraoperative fluid supply, red blood cell (RBC) concentrate and fresh frozen plasma (FFP) supply, blood loss, and diuresis. RESULTS A need for catecholamines has been shown to be more frequent in smokers (P=0.01), patients with cardiovascular comorbidities (P=0.037), high ASA PS scores (P=0.003), and preoperative ERCP (P=0.011). The need for intraoperative transfusion of RBC concentrate was more frequent in smokers (P=0.005). Surgical time was significantly longer in males (P=0.014). Among females, liberal intraoperative fluid therapy (>7.9 ml/kg/h) was more frequent in patients with thyroid comorbidities (P=0.003). CONCLUSIONS The findings of this retrospective study demonstrate the influence of comorbidities, ASA PS class, and catecholamine use on fluid therapy during pancreatoduodenectomy.

Accuracy of Estimated Continuous Cardiac Output Monitoring Using Pulse Wave Transit Time Compared to Arterial Pressure-based CO Measurement during Major Surgeries

Background

Pulse wave transit time is a novel method of estimating continuous cardiac output (esCCO). Since there are not many studies evaluating esCCO, we compared it with arterial pressure based cardiac output (APCO) method (FloTrac).

Methods

In this prospective single-center observational study, we included 50 adult patients planned to undergo supramajor oncosurgeries, where major blood loss and extensive fluid shifts were expected. Cardiac output (CO) measurements were obtained by both methods at five distinct time points, giving us 250 paired readings of stroke volume index (SVI) and cardiac index (CI). We analyzed these readings using Pearson's correlation coefficient and Bland–Altman plots, along with other appropriate statistical tests.

Results

There was significant correlation between CI and SVI measured by the esCCO and APCO. Bland–Altman plot analysis for CI showed a bias of −0.44 L/minute/m², precision of 0.74, and the limits of agreement of −1.89 and +1.01, while the percentage error was 46.29%. Bland–Altman analysis for SVI showed a bias −5.07 mL with a precision of 9.36, and the limits of agreement to be −23.4 to +13.28. The percentage error was 46.56%.

Conclusion

This study demonstrated that esCCO tended to underestimate the CI to a large degree, particularly while estimating the cardiac output in the lower range. We found that the limits of agreement between two methods were wide, which are not likely to be clinically acceptable. Further studies with larger number of data points, obtained in a similar subset of patients, for cardiac output measurement in the perioperative period will certainly help determine if pulse wave transit time (PWTT) is here to stay (CTRI No.: CTRI/2019/08/020543).

How to cite this article

Joshi M, Rathod R, Bhosale SJ, Kulkarni AP. Accuracy of Estimated Continuous Cardiac Output Monitoring (esCCO) Using Pulse Wave Transit Time (PWTT) Compared to Arterial Pressure-based CO (APCO) Measurement during Major Surgeries. Indian J Crit Care Med 2022;26(4):496–500.

Perioperative fluid administration and complications in emergency gastrointestinal surgery-an observational study

BACKGROUND

The fluid balance associated with a better outcome following emergency surgery is unknown. The aim of this study was to explore the association of the perioperative fluid balance and postoperative complications during emergency gastrointestinal surgery.

METHODS

We retrospectively included patients undergoing emergency surgery for gastrointestinal obstruction or perforation. A perioperative fluid balance of 2.5 L divided the cohort in a conservative and liberal group. Outcome was Clavien-Dindo graded complications registered 90 days postoperatively. We used logistic regression adjusted for age, sex, American Society of Anesthesiologists' classification, use of epidural analgesia, use of vasopressor, type of surgery, intraabdominal pathology, and hospital. Predicted risk of complications was demonstrated on a continuous scale of the fluid balance.

RESULTS

We included 342 patients operated between July 2014 and July 2015 from three centers. The perioperative fluid balance was 1.6 L IQR [1.0 to 2.0] in the conservative vs. 3.6 L IQR [3.0 to 5.3] in the liberal group. Odds ratio of overall 2.6 (95% CI 1.5 to 4.4), p < 0.001, and cardiopulmonary complications 3.2 (95% CI 1.9 to 5.7), p < 0.001, were increased in the liberal group. A perioperative fluid balance of 0-2 L was associated with minimal risk of cardiopulmonary complications compared to 1.5-3.5 L for renal complications.

CONCLUSION

We found a perioperative fluid balance above 2.5 L to be associated with an increased risk of overall and cardiopulmonary complications following emergency surgery for gastrointestinal obstruction or perforation. A perioperative fluid balance of 0-2 L was associated with the lowest risk of cardiopulmonary complications and 1.5-3.5 L for renal complications.

Post-operative outcomes of intra-operative restrictive and conventional fluid management in laparoscopic colorectal cancer surgery

Context

Intra-operative fluid management has been shown to significantly alter a patient's clinical condition in peri-operative care. Studies in the literature that investigated the effects of different amounts of intra-operative fluids on outcomes reported conflicting results.

Aims

To compare the post-operative results of intra-operative restrictive and conventional fluid administrations in laparoscopic colorectal cancer surgery.

Settings and Design

All patients with ASA I, II and III, and those who had undergone laparoscopic colorectal cancer surgery were included. It was a retrospective, cohort study.

Subjects and Methods

A review of laparoscopic colorectal cancer surgeries performed by the same fellow-trained colorectal surgeon with different anaesthesiologists between 1 January, 2018 and 30 November, 2021.

Results

In total 80 patients were analysed; 2 patients were excluded, 28 patients were in restrictive (Group R) and 50 patients were in the conventional (Group C) group. The median age of all patients was 63 years and 74% were male. The median (interquartile ranges 25 to 75) intra-operative fluid administration was significantly different between groups; 3 ml/kg/h in Group R, and 7.2 ml/kg/h in Group C. (P < 0.001) Patients in Group C had significantly high post-operative intensive care unit admission (P < 0.05), and hospital length of stay (P = 0.005) compared to Group R.

Conclusions

Intra-operative fluid management was significantly associated with post-operative hospital length of stay and intensive care unit admission. Excessive intra-operative fluid management should be avoided in daily practice to improve the outcomes of laparoscopic colorectal cancer surgery.

Unfavorable effect of high postoperative fluid balance on outcome of pancreaticoduodenectomy

Purpose

Despite the many efforts to overcome postoperative complications, pancreaticoduodenectomy (PD) is still accompanied with considerable concerns of lethal complications. The clinical factors are known to affect postoperative outcomes such as diameter of pancreatic duct, texture of pancreas, and comorbidity of the patients are mostly uncorrectable. Thus, investigation for correctable risk factors is required. Recently, perioperative fluid volume was reported to be associated with complications after PD. This study aims to determine the relationship between postoperative fluid balance and surgical outcome after open PD.

Methods

We reviewed, retrospectively, 172 consecutive patients who underwent open PD in a single institution between 2015 and 2019. The status of perioperative fluid balance 2 days after surgery and clinical factors were investigated to determine the association with postoperative outcome including postoperative pancreatic fistula (POPF). According to postoperative fluid balance, patients were divided into high- and low-balance groups, and clinical features and surgical outcomes were compared between both groups. Multivariate analysis were performed to identify risk factors for POPF.

Results

The percentage of morbidity and the incidence of POPF were higher in the high-balance group compared to the low-balance group (61.6% vs. 37.2%, P = 0.001; 15.1% vs. 3.5%, P = 0.009). High postoperative fluid balance and the presence cardiovascular disease were correlated with POPF on multivariate analysis (odds ratio [OR], 4.574; 95% confidence interval [CI], 1.229–17.029; P = 0.023 and OR, 3.517; 95% CI, 1.209–12.017; P = 0.045).

Conclusion

Higher amount of postoperative fluid balance and the presence of cardiovascular disease are associated with POPF after PD.

Fluid balance-adjusted creatinine in diagnosing acute kidney injury in the critically ill

Background

Acute kidney injury (AKI) is often diagnosed based on plasma creatinine (Cr) only. Adjustment of Cr for cumulative fluid balance due to potential dilution of Cr and subsequently missed Cr‐based diagnosis of AKI has been suggested, albeit the physiological rationale for these adjustments is questionable. Furthermore, whether these adjustments lead to a different incidence of AKI when used in conjunction with urine output (UO) criteria is unknown.

Methods

This was a post hoc analysis of the Finnish Acute Kidney Injury study. Hourly UO and daily plasma Cr were measured during the first 5 days of intensive care unit admission. Cr values were adjusted following the previously used formula and combined with the UO criteria. Resulting incidences and mortality rates were compared with the results based on unadjusted values.

Results

In total, 2044 critically ill patients were analyzed. The mean difference between the adjusted and unadjusted Cr of all 7279 observations was 5 (±15) µmol/L. Using adjusted Cr in combination with UO and renal replacement therapy criteria resulted in the diagnosis of 19 (1%) additional AKI patients. The absolute difference in the incidence was 0.9% (95% confidence interval [CI]: 0.3%‐1.6%). Mortality rates were not significantly different between the reclassified AKI patients using the full set of Kidney Disease: Improving Global Outcomes criteria.

Conclusion

Fluid balance‐adjusted Cr resulted in little change in AKI incidence, and only minor differences in mortality between patients who changed category after adjustment and those who did not. Using adjusted Cr values to diagnose AKI does not seem worthwhile in critically ill patients.

A scoping review of registry captured indicators for evaluating quality of critical care in ICU

BACKGROUND

Excess morbidity and mortality following critical illness is increasingly attributed to potentially avoidable complications occurring as a result of complex ICU management (Berenholtz et al., J Crit Care 17:1-2, 2002; De Vos et al., J Crit Care 22:267-74, 2007; Zimmerman J Crit Care 1:12-5, 2002). Routine measurement of quality indicators (QIs) through an Electronic Health Record (EHR) or registries are increasingly used to benchmark care and evaluate improvement interventions. However, existing indicators of quality for intensive care are derived almost exclusively from relatively narrow subsets of ICU patients from high-income healthcare systems. The aim of this scoping review is to systematically review the literature on QIs for evaluating critical care, identify QIs, map their definitions, evidence base, and describe the variances in measurement, and both the reported advantages and challenges of implementation.

METHOD

We searched MEDLINE, EMBASE, CINAHL, and the Cochrane libraries from the earliest available date through to January 2019. To increase the sensitivity of the search, grey literature and reference lists were reviewed. Minimum inclusion criteria were a description of one or more QIs designed to evaluate care for patients in ICU captured through a registry platform or EHR adapted for quality of care surveillance.

RESULTS

The search identified 4780 citations. Review of abstracts led to retrieval of 276 full-text articles, of which 123 articles were accepted. Fifty-one unique QIs in ICU were classified using the three components of health care quality proposed by the High Quality Health Systems (HQSS) framework. Adverse events including hospital acquired infections (13.7%), hospital processes (54.9%), and outcomes (31.4%) were the most common QIs identified. Patient reported outcome QIs accounted for less than 6%. Barriers to the implementation of QIs were described in 35.7% of articles and divided into operational barriers (51%) and acceptability barriers (49%).

CONCLUSIONS

Despite the complexity and risk associated with ICU care, there are only a small number of operational indicators used. Future selection of QIs would benefit from a stakeholder-driven approach, whereby the values of patients and communities and the priorities for actionable improvement as perceived by healthcare providers are prioritized and include greater focus on measuring discriminable processes of care.

Understanding Restrictive Versus Liberal Fluid Therapy for Major Abdominal Surgery Trial Results: Did Liberal Fluids Associate With Increased Endothelial Injury Markers?

Supplemental Digital Content is available in the text.

Liberal fluid strategies in critically ill patients are associated with harm, thought to be due to endothelial and glycocalyx injury. As the restrictive versus liberal fluid therapy for major abdominal surgery trial not only failed to report survival benefit with restrictive fluids but was associated with a higher rate of acute kidney injury, we hypothesized that factors other than endothelial and glycocalyx injury were likely to account for these findings. Consequently, we measured injury biomarkers in a cohort of the restrictive versus liberal fluid therapy for major abdominal surgery trial.

Early Treatment with Human Albumin Solution in Continuous Renal Replacement Patients

AIMS

To study the impact of early human albumin solution (HAS) in continuous renal replacement therapy (RRT) patients.

METHODS

Analysis of Randomized Evaluation of Normal versus Augmented Level (RENAL) RRT trial data.

RESULTS

Of 1,464 patients, 500 (34%) received early albumin. These patients had higher illness severity scores, greater use of mechanical ventilation, and 90-day mortality (51 vs. 41%; p < 0.001). However, early albumin carried similar RRT dependence risk among survivors at day 90 (4.9 vs. 5.8%; p = 0.62). On Cox proportional hazards regression, with standardized inverse probability of treatment weighting, early albumin was not associated with increased mortality (hazard ratio [HR]: 1.23, 95% CI: 0.97-1.55; p = 0.09) or recovery to RRT independence (HR: 0.92, 95% CI: 0.78-1.10; p = 0.38).

CONCLUSIONS

Early albumin was administered to one-third of RENAL trial patients and in those with greater illness severity. Early albumin was not independently associated with mortality risk or rate of recovery to RRT independence.

Strategies to Reduce Perioperative Nephrotoxicity

Postoperative acute kidney injury (AKI) is a common complication of surgery that is associated with significant adverse outcomes, including increased morbidity and mortality. The perioperative burden of AKI risk factors is complex and potentially large, including high-risk nephrotoxic medications, hypotension, hypovolemia, radiologic contrast, anemia, and surgery-specific factors. Understanding the pathogenesis, risk factors, and potential cumulative impact of perioperative nephrotoxic exposures is particularly important in the prevention and reduction of perioperative AKI. This review outlines the possible strategies to reduce perioperative nephrotoxicity and the development of postoperative AKI.

Intraoperative fluid therapy and postoperative complications during minimally invasive esophagectomy for esophageal cancer: a single-center retrospective study

PURPOSE

Compared with open thoracotomy, minimally invasive esophagectomy (MIE) methods, such as transhiatal or thoracoscopic esophagectomy, likely have lower morbidity. However, the relationship between intraoperative fluid management and postoperative complications after MIE remains unclear. Thus, we investigated the association of cumulative intraoperative fluid balance and postoperative complications in patients undergoing MIE.

METHODS

This single-center retrospective cohort study examined patients undergoing thoracoscopic esophagectomy for esophageal cancer in the prone position. Postoperative complications included pneumonia, arrhythmia, thrombotic events and acute kidney injury (AKI). We compared patients with higher and lower intraoperative fluid balance (higher and lower than the median). Multivariable logistic regression analyses were performed to estimate the odds ratio of intraoperative fluid balance status on the incidence of postoperative complications.

RESULTS

In total, 135 patients were included in the study. Postoperative complications occurred in 43 (32%), including cardiac arrhythmia (n = 12, 9%), thrombosis (n = 20, 15%), pneumonia (n = 13, 10%), and AKI required hemodialysis (n = 1, 1%). Patients with a higher fluid balance had higher incidence of complications than those with a lower fluid balance (46% vs. 18%, p < 0.001). After adjusting for age, ASA-PS ≥ III, blood loss, and the use of radical surgery, the higher intraoperative fluid balance group was significantly and independently associated with postoperative complications (adjusted OR 5.31, 95% CI 2.26-13.6, p < 0.0001).

CONCLUSIONS

In patients undergoing thoracoscopic esophagectomy in the prone position, a greater intraoperative positive fluid balance was independently associated with a higher incidence of complications.

Association of Obesity With Septic Complications After Major Abdominal Surgery: A Secondary Analysis of the RELIEF Randomized Clinical Trial

IMPORTANCE

Body mass index (BMI) has been the most common obesity measure to assess perioperative risk; however, cardiometabolic risk is associated with the burden of visceral fat. Definitive evidence on the association of visceral fat measures, such as waist circumference and waist-to-hip ratio (WHR), with postoperative complications is lacking.

OBJECTIVE

To compare the value of waist circumference with the value WHR and BMI in predicting adverse outcomes, including major septic complications and persistent disability, following major abdominal surgery.

DESIGN, SETTING, AND PARTICIPANTS

This planned secondary analysis of the Restrictive vs Liberal Fluid Therapy for Major Abdominal Surgery (RELIEF) randomized clinical trial took place at 47 centers in 7 countries between October 2013 and September 2016, with 90-day follow-up. A total of 2954 adult RELIEF participants were coenrolled in this secondary analysis. Data analysis took place from December 2018 to September 2019.

EXPOSURES

Waist circumference, WHR, and BMI measurements.

MAIN OUTCOMES AND MEASURES

The primary outcomes were 30-day major septic complications and 90-day persistent disability or death.

RESULTS

Of 2954 eligible participants, 2755 were included (mean [SD] age, 65.9 [12.9] years; 1426 [51.8%] men) in the final analysis. A total of 564 participants (20.6%) experienced at least 1 major septic complication within 30 days after surgery (sepsis, 265 [9.7%]; surgical site infection, 409 [14.9%]; anastomotic leak, 78 [2.8%]; pneumonia, 104 [3.8%]). Waist circumference had a statistically significantly larger odds ratio (OR) and discrimination indices as well as a smaller prediction error than WHR or BMI for 30-day major septic complications or death (waist circumference: OR, 1.44; 95% CI, 1.28-1.62; P < .001; area under the receiver operating characteristic curve, 0.641; net reclassification index, 0.266; integrated discrimination improvement [score × 104], 152.98; Brier score, 0.162; WHR: OR, 1.15; 95% CI, 1.03-1.28; P = .01; area under the receiver operating characteristic curve, 0.621; net classification index, 0.199; integrated discrimination improvement [score × 104], 28.47; Brier score, 0.164; BMI: OR, 1.33; 95% CI, 1.17-1.50; P < .001; area under the receiver operating characteristic curve, 0.629; net reclassification index, 0.205; integrated discrimination improvement [score × 104], 85.61; Brier score, 0.163) but not for any other outcomes.

CONCLUSIONS AND RELEVANCE

In this secondary analysis of the RELIEF randomized clinical trial, waist circumference was observed to be superior to other adiposity indices in predicting 30-day major septic complications alone or in conjunction with death following elective major abdominal surgery. Findings suggest that waist circumference is a useful adiposity measure that should be incorporated in preoperative risk assessment for such complications.

TRIAL REGISTRATION

ClinicalTrials.gov identifier: NCT01424150.

Restricting Intraoperative Fluid Volume Allows Earlier Return of Bowel Function After Colon and Rectal Surgery

BACKGROUND

Return of bowel function (ROBF) after abdominal surgery is an important determinant of patient outcomes. The role of intraoperative fluids (IOFs) in colon surgery remains unclear. The aim of this study was to assess the impact of IOF on ROBF in patients undergoing colon surgery. We hypothesized that minimizing IOFs allows earlier ROBF.

METHODS

A 2-year (2016-2017) retrospective analysis of all patients undergoing elective colon resection was performed at our tertiary hospital using a protocol limiting IOF and postoperative narcotics. Patients were divided into two groups: preprotocol (2016) and postprotocol (PoP) (2017). Patients were matched using propensity score matching for age, gender, comorbidities, Anesthesiology Severity Score, indication for procedure, and procedure type. The outcome measured was ROBF. Secondary outcome measures were complication rates and hospital length of stay.

RESULTS

A total of 360 patients were analyzed. After propensity matching, 90 patients (preprotocol: 45; PoP: 45) were included. The mean age was 62.2 ± 14.8 y, 43.3% male, and 44.4% of procedures were performed laparoscopically. There was no difference in demographics and comorbidities between groups. PoP patients received lower IOF (P = 0.036, 2016: 1198.8 ± 1096.5 mL, 2017: 2176.7 ± 1458.3 mL) and lower postoperative narcotics (P = 0.042). PoP patients had earlier ROBF 2[2-4], 4[3-5] (odds ratio: 1.18 [1.05-1.52], P = 0.04), shorter length of stay 3[2-5] d versus 5[4-7] (odds ratio: 1.11 [1.09-1.89], P = 0.043), and trended toward lower complication rates (P = 0.09).

CONCLUSIONS

IOF volume independently impacts ROBF after colon surgery. Restricting IOF allows for earlier bowel function and shorter hospital stay. Further studies defining optimum fluid management impacting ROBF may help optimize patient care.

Standardization of perioperative care facilitates safe discharge by postoperative day five after pancreaticoduodenectomy

INTRODUCTION

Pancreaticoduodenectomy is a complex surgical procedure associated with high morbidity and prolonged length of stay. Enhanced recovery after surgery principles have reduced complications rate and length of stay for multiple types of operations. We hypothesized that implementation of a standardized perioperative care pathway would facilitate safe discharge by five days after pancreaticoduodenectomy.

METHODS

We performed a retrospective cohort study of patients undergoing pancreaticoduodenectomy 18 months prior to and 18 months following implementation of a perioperative care pathway at a quaternary center performing high volume pancreatic surgery.

RESULTS

A total of 145 patients underwent pancreaticoduodenectomy (mean age 63 ± 10 years, 52% female), 81 before and 64 following pathway implementation, and the groups were similar in terms of preoperative comorbidities. The percentage of patients discharged within 5 days of surgery increased from 36% to 64% following pathway implementation (p = 0.001), with no observed differences in post-operative serious adverse events (p = 0.34), pancreatic fistula grade B or C (p = 0.28 and p = 0.27 respectively), or delayed gastric emptying (p = 0.46). Multivariate regression analysis showed length of stay ≤5 days three times more likely after pathway implementation. Rates of readmission within 30 days (20% pre- vs. 22% post-pathway (p = 0.75)) and 90 days (27% pre- vs. 36% post-pathway (p = 0.27)) were unchanged after pathway implementation, and were no different between patients discharged before or after day 5 at both 30 days (19% ≤5 days vs. 23% ≥ 6 days (p = 0.68)) and 90 days (32% ≤5 days vs. 30% ≥ 6 days (p = 0.81)).

CONCLUSIONS

Standardizing perioperative care via enhanced recovery protocols for patients undergoing pancreaticoduodenectomy facilitates safe discharge by post-operative day five.

Restrictive versus Liberal Fluid Therapy for Major Abdominal Surgery

BACKGROUND

Guidelines to promote the early recovery of patients undergoing major surgery recommend a restrictive intravenous-fluid strategy for abdominal surgery. However, the supporting evidence is limited, and there is concern about impaired organ perfusion.

METHODS

In a pragmatic, international trial, we randomly assigned 3000 patients who had an increased risk of complications while undergoing major abdominal surgery to receive a restrictive or liberal intravenous-fluid regimen during and up to 24 hours after surgery. The primary outcome was disability-free survival at 1 year. Key secondary outcomes were acute kidney injury at 30 days, renal-replacement therapy at 90 days, and a composite of septic complications, surgical-site infection, or death.

RESULTS

During and up to 24 hours after surgery, 1490 patients in the restrictive fluid group had a median intravenous-fluid intake of 3.7 liters (interquartile range, 2.9 to 4.9), as compared with 6.1 liters (interquartile range, 5.0 to 7.4) in 1493 patients in the liberal fluid group (P<0.001). The rate of disability-free survival at 1 year was 81.9% in the restrictive fluid group and 82.3% in the liberal fluid group (hazard ratio for death or disability, 1.05; 95% confidence interval, 0.88 to 1.24; P=0.61). The rate of acute kidney injury was 8.6% in the restrictive fluid group and 5.0% in the liberal fluid group (P<0.001). The rate of septic complications or death was 21.8% in the restrictive fluid group and 19.8% in the liberal fluid group (P=0.19); rates of surgical-site infection (16.5% vs. 13.6%, P=0.02) and renal-replacement therapy (0.9% vs. 0.3%, P=0.048) were higher in the restrictive fluid group, but the between-group difference was not significant after adjustment for multiple testing.

CONCLUSIONS

Among patients at increased risk for complications during major abdominal surgery, a restrictive fluid regimen was not associated with a higher rate of disability-free survival than a liberal fluid regimen and was associated with a higher rate of acute kidney injury. (Funded by the Australian National Health and Medical Research Council and others; RELIEF ClinicalTrials.gov number, NCT01424150 .).

Predictors of major complications after elective abdominal surgery in cancer patients

Background

Patients undergoing abdominal surgery for solid tumours frequently develop major postoperative complications, which negatively affect quality of life, costs of care and survival. Few studies have identified the determinants of perioperative complications in this group.

Methods

We performed a prospective observational study including all patients (age > 18) undergoing abdominal surgery for cancer at a single institution between June 2011 and August 2013. Patients undergoing emergency surgery, palliative procedures, or participating in other studies were excluded. Primary outcome was a composite of 30-day all-cause mortality and infectious, cardiovascular, respiratory, neurologic, renal and surgical complications. Univariate and multiple logistic regression analyses were performed to identify predictive factors for major perioperative adverse events.

Results

Of a total 308 included patients, 106 (34.4%) developed a major complication during the 30-day follow-up period. Independent predictors of postoperative major complications were: age (odds ratio [OR] 1.03 [95% CI 1.01–1.06], p = 0.012 per year), ASA (American Society of Anesthesiologists) physical status greater than or equal to 3 (OR 2.61 [95% CI 1.33–5.17], p = 0.003), a preoperative haemoglobin level lower than 12 g/dL (OR 2.13 [95% CI 1.21–4.07], p = 0.014), intraoperative use of colloids (OR 1.89, [95% CI 1.03–4.07], p = 0.047), total amount of intravenous fluids (OR 1.22 [95% CI 0.98–1.59], p = 0.106 per litre), intraoperative blood losses greater than 500 mL (2.07 [95% CI 1.00–4.31], p = 0.043), and hypotension needing vasopressor support (OR 4.68 [95% CI 1.55–27.72], p = 0.004). The model had good discrimination with the area under the ROC curve being 0.80 (95% CI 0.75–0.84, p < 0.001).

Conclusions

Our findings suggest that a perioperative strategy aimed at reducing perioperative complications in cancer surgery should include treatment of preoperative anaemia and an optimal fluid strategy, avoiding fluid overload and intraoperative use of colloids.

Electronic supplementary material

The online version of this article (10.1186/s12871-018-0516-6) contains supplementary material, which is available to authorized users.

The effect of a perioperative ketamine infusion on the incidence of chronic postsurgical pain-a pilot study

Chronic postsurgical pain (CPSP) is a common and debilitating complication of major surgery. We undertook a pilot study at three hospitals to assess the feasibility of a proposed large multicentre placebo-controlled randomised trial of intravenous perioperative ketamine to reduce the incidence of CPSP. Ketamine, 0.5 mg/kg pre-incision, 0.25 mg/kg/hour intraoperatively and 0.1 mg/kg/hour for 24 hours, or placebo, was administered to 80 patients, recruited over a 15-month period, undergoing abdominal or thoracic surgery under general anaesthesia. The primary endpoint was CPSP in the area of the surgery reported at six-month telephone follow-up using a structured questionnaire. Fourteen patients (17.5%) reported CPSP (relative risk [95% confidence interval] if received ketamine 1.18 [0.70 to 1.98], P=0.56). Four patients in the treatment group and three in the control group reported ongoing analgesic use to treat CPSP and two patients in each group reported their worst pain in the previous 24 hours at ≥3/10 at six months. There were no significant differences in adverse event rates, quality of recovery scores, or cumulative morphine equivalents consumption in the first 72 hours. Numeric Rating Scale pain scores (median [interquartile range, IQR]) for average pain in the previous 24 hours among those patients reporting CPSP were 17.5 [0 to 40] /100 with no difference between treatment groups. A large (n=4,000 to 5,000) adequately powered multicentre trial is feasible using this population and methodology.

The impact of fluid intervention on complications and length of hospital stay after pancreaticoduodenectomy (Whipple's procedure)

BACKGROUND

There is limited information on the impact on perioperative fluid intervention on complications and length of hospital stay following pancreaticoduodenectomy. Therefore, we conducted a detailed analysis of fluid intervention in patients undergoing pancreaticoduodenectomy at a university teaching hospital to test the hypothesis that a restrictive intravenous fluid regime and/or a neutral or negative cumulative fluid balance, would impact on perioperative complications and length of hospital stay.

METHODS

We retrospectively obtained demographic, operative details, detailed fluid prescription, complications and outcomes data for 150 consecutive patients undergoing pancreaticoduodenectomy in a university teaching hospital. Prognostic predictors for length of hospital stay and complications were determined.

RESULTS

One hundred and fifty consecutive patients undergoing pancreaticoduodenectomy were evaluated between 2006 and 2012. The majority of patients were, middle-aged, overweight and ASA class III. Postoperative complications were frequent and occurred in 86 patients (57%). The majority of complications were graded as Clavien-Dindo Class 2 and 3. Postoperative pancreatic fistula occurred in 13 patients (9%), and delayed gastric emptying occurred in 25 patients (17%). Other postoperative surgical complications included sepsis (22%), bile leak (4%), and postoperative bleeding (2%). Serious medical complications included pulmonary edema (6%), myocardial infarction (8%), cardiac arrhythmias (13%), respiratory failure (8%), and renal failure (7%). Patients with complications received a higher median volume of intravenous therapy and had higher cumulative positive fluid balances. Postoperative length of stay was significantly longer in patients with complications (median 25 days vs. 10 days; p < 0.001). After adjustment for covariates, a fluid balance of less than 1 litre on postoperative day 1 and surgeon caseloads were associated with the development of complications.

CONCLUSIONS

In the context of pancreaticoduodenectomy, restrictive perioperative fluid intervention and negative cumulative fluid balance were associated with fewer complications and shorter length of hospital stay. These findings provide good opportunities to evaluate strategies aimed at improving perioperative care.