Role of intraoperative oliguria in risk stratification for postoperative acute kidney injury in patients undergoing colorectal surgery with an enhanced recovery protocol: A propensity score matching analysis

Systemic inflammation and acute kidney injury after colorectal surgery

BACKGROUND

In this retrospective review, the relative importance of systemic inflammation among other causes of acute kidney injury (AKI) was investigated in 1224 consecutive colorectal surgery patients. A potential benefit from reducing excessive postoperative inflammation on AKI might then be estimated.

METHODS

AKI was determined using the Kidney Disease Improving Global Outcomes (KDIGO) criteria. The entire population (mixed group), composed of patients with or without sepsis, and a subpopulation of patients without sepsis (aseptic group) were examined. Markers indicative of inflammation were procedure duration, the first postoperative white blood cell (POD # 1 WBC) for the mixed population, and the neutrophil-to-lymphocyte ratio (POD #1 NLR) for the aseptic population. Multivariable logistic regression was then performed using significant (P < 0.05) predictors. The importance of inflammation among independent predictors of AKI and AKI-related complications was then assessed.

RESULTS

AKI occurred in 24.6% of the total population. For the mixed population, there was a link between inflammation (POD # 1 WBC) and AKI (P = 0.0001), on univariate regression. Medications with anti-inflammatory properties reduced AKI: ketorolac (P = 0.047) and steroids (P = 0.038). Similarly, in an aseptic population, inflammation (POD # 1 NLR) contributed significantly to AKI (P = 0.000). On multivariable analysis for the mixed and aseptic population, the POD #1 WBC and the POD #1 NLR were independently associated with AKI (P = 0.000, P = 0.022), as was procedure duration (P < 0.0001, P < 0.0001). Inflammation-related parameters were the most significant contributors to AKI. AKI correlated with complications: postoperative infections (P = 0.016), chronic renal insufficiency (CRI, P < 0.0001), non-infectious complications (P = 0.010), 30-day readmissions (P = 0.001), and length of stay (LOS, P < 0.0001). Inflammation, in patients with or without sepsis, was similarly a predictor of complications: postoperative infections (P = 0.002, P = 0.008), in-hospital complications (P = 0.000, P = 0.002), 30-day readmissions (P = 0.012, P = 0.371), and LOS (P < 0.0001, P = 0.006), respectively.

CONCLUSIONS

Systemic inflammation is an important cause of AKI. Limiting early postsurgical inflammation has the potential to improve postoperative outcomes.

A multi-national survey to identify health professionals' opinions for the appropriate frequency of urine output monitoring in post-operative patients

Urine output is an important clinical measurement and oliguria may highlight the development of acute kidney injury (AKI) earlier than serum creatinine (sCr). Despite the importance of urine output monitoring, there are no definitive guidelines or recommendations for best practice. A survey was sent to healthcare professionals with a specialist interest in AKI to gather opinions of what constitutes a good standard of urine output monitoring and by corollary missed care, post- major surgery. Data was gathered from 221 respondents. Results will inform audit and improvement projects in post-operative nursing care.

Association of urine output during cardiopulmonary bypass and postoperative acute kidney injury in patients undergoing coronary artery bypass graft

Acute kidney injury (AKI) is a common complication in patients undergoing coronary artery bypass graft (CABG) surgery and is associated with significant morbidity and mortality. We investigated the association of urine output (U/O) during cardiopulmonary bypass (CPB) with postoperative AKI in a cohort of patients undergoing elective CABG.

This single-center retrospective study used data from patients undergoing elective CABG with CPB (March 2015 to March 2020). Demographic data and perioperative information were extracted from the Patients' records. Urine output during CPB and in the first 3 days after surgery was also recorded. Acute kidney injury was defined according to the Acute Kidney Injury Network (AKIN) classification. Spearman's correlation analysis was used to evaluate the relationship between quantitative variables and multiple logistic regression analysis was applied to determine AKI predictors.

A total of 532 patients with a mean age of 56.83 ± 7.99 years were analyzed. In the first 48 h after surgery, the incidence of AKI was 18%, of which, 7 (2.7%) patients developed stage II of AKI. There was no significant correlation between U/O during CPB and change in postoperative blood urea nitrogen (BUN) and creatinine. Oliguria during CPB was not observed in any of the patients. Age and duration of bypass were identified as predictors of AKI.

In this study, the incidence of AKI was 18% and there was no significant correlation between U/O during CPB and changes in postoperative BUN and creatinine. Age and duration of bypass were independent risk factors of AKI.

Framework, component, and implementation of enhanced recovery pathways

The introduction of enhanced recovery pathways (ERPs) has led to a considerable paradigm shift towards evidence-based, multidisciplinary perioperative care. Such pathways are now widely implemented in a variety of surgical specialties, with largely positive results. In this narrative review, we summarize the principles, components and implementation of ERPs, focusing on recent developments in the field. We also discuss ‘special cases’ in ERPs, including: surgery in frail patients; emergency procedures; and patients with Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2/COVID-19).

Management of acute kidney injury in gastrointestinal tumor: An overview

Gastrointestinal tumors remain a global health problem. Acute kidney injury (AKI) is a common complication during the treatment of gastrointestinal tumors. AKI can cause a decrease in the remission rate and an increase in mortality. In this review, we analyzed the causes and risk factors for AKI in gastrointestinal tumor patients. The possible mechanisms of AKI were divided into three groups: pretreatment, intrafraction and post-treatment causes. Treatment and prevention measures were proposed according to various factors to provide guidance to clinicians and oncologists that can reduce the incidence of AKI and improve the quality of life and survival rate of gastrointestinal tumor patients.

Acute Kidney Injury within an Enhanced Recovery after Surgery (ERAS) Program for Colorectal Surgery

BACKGROUND

We aimed to determine the prevalence, risk factors, and outcomes of acute kidney injury (AKI) within an ERAS program for colorectal surgery (CRS).

METHODS

This is a retrospective case-control study conducted from March 2016 to September 2018 at a single tertiary hospital in Singapore. All adult patients requiring CRS within our ERAS program were considered eligible. Exclusions were stage 5 chronic kidney disease or patients requiring a synchronous liver resection. The primary outcome was AKI as defined by the Kidney Disease Improving Global Outcomes (KDIGO) Acute Kidney Injury Work Group. Secondary outcomes included mortality, major complications, and hospital length of stay. Patient, surgical, and anaesthesia-related data were analysed to determine factors associated with AKI.

RESULTS

A total of 575 patients were eligible for the study. Twenty patients were excluded from the study leaving 555 patients for analysis. Mean age was 67.8 (SD 11.4) years. Seventy-four patients met the criteria for AKI (13.4%: stage 1-11.2%, stage 2-2.0%, stage 3-0.2%). One patient required renal replacement therapy (RRT). Patients with AKI had a longer length of stay (median [IQR], 11.0 [5.0-17.0] days vs 6.0 [4.0-8.0] days; P < .001), more major complications (OR, 6.55; 95% CI, 3.00-14.35, P < .001), and a trend towards higher mortality at one year (OR, 1.44; 95% CI 0.48-4.30; p = 0.511. After multivariable regression analysis, factors associated with AKI were preoperative creatinine (OR, 1.01 per 10 µmol/l; 95% CI, 1.03-1.22; P = 0.01), robotic surgery vs open surgery (OR, 0.15; 95% CI, 0.06-0.39; P < 0.001), anaesthesia duration (OR, 1.38 per hour; 95% CI, 1.22-1.55; P < 0.001), and major complications (OR, 5.55; 95% CI, 2.63-11.70; P < 0.001).

CONCLUSIONS

Within the present cohort, the implementation of an ERAS program for CRS was associated with a low prevalence of moderate to severe AKI despite a balanced intravenous fluid regimen. Patients having open surgery, longer procedures, and major complications are at increased risk of AKI.

An enhanced recovery protocol decreases complication rates in high-risk gynecologic oncology patients undergoing non-emergent laparotomy

OBJECTIVE

Enhanced recovery protocols are now established as the standard of care leading to improved perioperative outcomes and associated cost-benefits. The objective of this study was to evaluate the impact of an enhanced recovery program on complication rates in high-risk gynecologic oncology patients undergoing surgery.

METHODS

This retrospective cohort study included gynecologic oncology patients with pathology-proven malignancy undergoing non-emergent laparotomy from October 2016 to December 2018 managed on an enhanced recovery protocol, and a control group from October 2015 through September 2016 prior to enhanced recovery protocol implementation. The primary outcome was complication rates in a high-risk population pre- and post-enhanced recovery protocol. High-risk patients were defined as those with obesity (body mass index >30 kg/m2) and/or age ≥65 years. Analysis was performed using Statistical Package for Social Sciences (SPSS) v.24.

RESULTS

A total of 363 patients met the inclusion criteria: 104 in the control group and 259 in the enhanced recovery protocol group. Patient demographics, including age, body mass index, diagnosis, and performance status, were similar. Overall complication rates were less in the enhanced recovery protocol group (29% vs 53.8%; p<0.0001). The enhanced recovery protocol group had a shorter length-of-stay compared with control (3.3 vs 4.2 days; p<0.0001). The 30-day readmission rates were similar between the groups (9.6% vs 13.5%; p=0.19). In the enhanced recovery protocol group compared with control, complication rates were less in obese patients (29.4% vs 57.8%; p<0.0001), morbidly obese patients (20.9% vs 76.2%; p<0.0001), and age ≥65 (36.1% vs 57.1%; p<0.0001). The most common complications in the enhanced recovery protocol group were ileus (9.7%), pulmonary complications (2.7%), and blood transfusions (10.8%).

CONCLUSIONS

Implementation of an enhanced recovery protocol decreases complication rates and length-of-stay in morbidly obese and geriatric patients with gynecologic malignancy without an increase in readmission rates.

Assessment of prognostic value of intraoperative oliguria for postoperative acute kidney injury: a retrospective cohort study

BACKGROUND

Oliguria is often viewed as a sign of renal hypoperfusion and an indicator for volume expansion during surgery. However, the prognostic association and the predictive utility of intraoperative oliguria for postoperative acute kidney injury (AKI) are unclear.

METHODS

We conducted a retrospective cohort study on patients undergoing major thoracic surgery in an academic hospital to assess the association of intraoperative oliguria with postoperative AKI and its predictive value. To contextualise our findings, we included our results in a meta-analysis of observational studies on the importance of oliguria during noncardiac surgery.

RESULTS

In our cohort study, 3862 patients were included; 205 (5.3%) developed AKI after surgery. Intraoperative urine output of 0.3 ml kg-1 h-1 was the optimal threshold for oliguria in multivariable analysis. Patients with oliguria had an increased risk of AKI (adjusted odds ratio: 2.60; 95% confidence interval: 1.24-5.05). However, intraoperative oliguria had a sensitivity of 5.9%, specificity of 98%, positive likelihood ratio of 2.74, and negative likelihood ratio of 0.96, suggesting poor predictive ability. Moreover, it did not improve upon the predictive performance of a multivariable model, based on discrimination and reclassification indices. Our findings were generally consistent with the results of a systematic review and meta-analysis, including six additional studies.

CONCLUSIONS

Intraoperative oliguria has moderate association with, but poor predictive ability for, postoperative AKI. It remains of clinical interest as a risk factor potentially modifiable to interventions.

Male Patients may be More Vulnerable to Acute Kidney Injury After Colorectal Surgery in an Enhanced Recovery Program: A Propensity Score Matching Analysis

BACKGROUND

Although many reports have shown that enhanced recovery after surgery (ERAS) programs improve the perioperative outcomes of patients undergoing colorectal surgery, the prevalence of early acute kidney injury (AKI) after surgery in such patients requires attention. Protective roles of the female sex in terms of chronic kidney disease and progression of ischemic renal injury have been described in many studies. We thus explored whether a sex difference was evident in terms of postoperative AKI in a colorectal ERAS setting.

METHODS

From January 2017 to August 2019, 453 patients underwent laparoscopic colorectal cancer resection in an enhanced recovery program. Of these, 217 female patients were propensity score (PS)-matched with 236 male patients. Then, 215 patients of either sex were compared in terms of postoperative renal function and complications.

RESULTS

Among the PS-matched patients, the incidence of AKI was significantly higher in male than female patients (24.2% vs. 9.8%, P < 0.001). Male patients also exhibited a greater reduction in the postoperative estimated glomerular filtration rate, compared with female patients. The male sex was associated with an approximately threefold increase in the risk of AKI. The rate of surgical complications was significantly higher in male than female patients.

CONCLUSIONS

Caution must be taken to prevent postoperative AKI in patients (particularly males) participating in colorectal ERAS programs. The mechanism underlying the sex difference remains unclear. Additional studies are required to determine whether male patients require perioperative management that differs from that of females, to prevent postoperative AKI.