Restrictive versus Liberal Fluid Therapy for Major Abdominal Surgery

Mitigating Intraoperative Hypotension: A Review and Update on Recent Advances

Intraoperative hypotension (IOH) is a common occurrence during anesthesia administration for various surgical procedures and is linked to postoperative adverse outcomes. Factors contributing to IOH include hypovolemia, vasodilation, and impaired contractility, often combined with patient comorbidities. Strategies for mitigating IOH have been developed and are continually being updated with new research and technological advancements. These strategies include personalized blood pressure thresholds, pharmacologic measures, and the use of predictive tools. However, the management of IOH also requires careful consideration of patient-specific comorbidities and the use of appropriate treatment options.

Relationship between intra-operative urine output and postoperative acute kidney injury in paediatric cardiac surgery: A retrospective observational study

BACKGROUND

Intra-operative urine output (UO) has been shown to predict postoperative acute kidney injury (AKI) in adults; however, its significance in children undergoing cardiac surgery remains unknown.

OBJECTIVE

To explore the association between intra-operative UO and postoperative AKI in children with congenital heart disease.

DESIGN

A retrospective observational study.

SETTING

A tertiary hospital.

PATIENTS

Children aged >28 days and <6 years who underwent cardiac surgery at Fuwai Hospital from 1 April 2022 to 30 August 2022.

MAIN OUTCOME MEASURES

AKI was identified by the highest serum creatinine value within postoperative 7 days using Kidney Disease Improving Global Outcomes (KDIGO) criteria.

RESULTS

In total, 1184 children were included. The incidence of AKI was 23.1% (273/1184), of which 17.7% (209/1184) were stage 1, 4.2% (50/1184) were stage 2, and others were stage 3 (1.2%, 14/1184). Intra-operative UO was calculated by dividing the total intra-operative urine volume by the duration of surgery and the actual body weight measured before surgery. There was no significant difference in median [IQR] intra-operative UO between the AKI and non-AKI groups (2.6 [1.4 to 5.4] and 2.7 [1.4 to 4.9], respectively, P  = 0.791), and multivariate logistic regression analyses showed that intra-operative UO was not associated with postoperative AKI [adjusted odds ratio (OR) 0.971; 95% confidence interval (CI), 0.930 to 1.014; P  = 0.182]. Regarding the clinical importance of severe forms of AKI, we further explored the association between intra-operative UO and postoperative moderate-to-severe AKI (adjusted OR 0.914; 95% CI, 0.838 to 0.998; P  = 0.046).

CONCLUSIONS

Intra-operative UO was not associated with postoperative AKI during paediatric cardiac surgery. However, we found a significant association between UO and postoperative moderate-to-severe AKI. This suggests that reductions in intra-operative urine output below a specific threshold may be associated with postoperative renal dysfunction.

TRIAL REGISTRATION

Clinicaltrials.gov identifier: NCT05489263.

Fluid management in the septic peri-operative patient

PURPOSE OF REVIEW

This review provides insight into recent clinical studies involving septic peri-operative patients and highlights gaps in understanding fluid management. The aim is to enhance the understanding of safe fluid resuscitation to optimize peri-operative outcomes and reduce complications.

RECENT FINDINGS

Recent research shows adverse surgical and clinical outcomes with both under- and over-hydration of peri-operative patients. The kinetic of intravenous fluids varies significantly during surgery, general anaesthesia, and sepsis with damage to endothelial glycocalyx (EG), which increases vascular permeability and interstitial oedema. Among clinical anaesthesia, neuraxial anaesthesia and sevoflurane have less effect on EG. Hypervolemia and the speed and volume of fluid infusion are also linked to EG shedding. Despite improvement in the antisepsis strategies, peri-operative sepsis is not uncommon. Fluid resuscitation is the cornerstone of sepsis management. However, overzealous fluid resuscitation is associated with increased mortality in patients with sepsis and septic shock. Personalized fluid resuscitation based on a careful assessment of intravascular volume status, dynamic haemodynamic variables and fluid tolerance appears to be a safe approach. Balanced solutions (BS) are preferred over 0.9% saline in patients with sepsis and septic shock due to a potential reduction in mortality, when exclusive BS are used and/or large volume of fluids are required for fluid resuscitation. Peri-operative goal-directed fluid therapy (GDFT) using dynamic haemodynamic variables remains an area of interest in reducing postoperative complications and can be considered for sepsis management (Supplementary Digital Content).

SUMMARY

Optimization of peri-operative fluid management is crucial for improving surgical outcomes and reducing postoperative complications in patients with sepsis. Individualized and GDFT using BS is the preferred approach for fluid resuscitation in septic peri-operative patients. Future research should evaluate the interaction between clinical anaesthesia and EG, its implications on fluid resuscitation, and the impact of GDFT in septic peri-operative patients.

Acknowledging acute kidney disease following ureteroscopy and laser lithotripsy: results from a tertiary care referral center

BACKGROUND

Acute kidney disease (AKD) is a recently described syndrome consisting of kidney function abnormalities lasting less than 3 months. Little is known regarding AKD following ureteroscopy (URS) and laser lithotripsy.

OBJECTIVE

To evaluate the occurrence and evolution of AKD in stone patients treated with URS.

MATERIALS AND METHODS

Data from 284 patients treated with URS for urinary stones were retrospectively analyzed. According to the KDIGO 2020 criteria, AKD was defined as postoperative acute kidney injury (AKI) occurrence, estimated glomerular filtration rate (eGFR) decrease ≥ 35%, or serum creatinine (SCr) increase ≥ 50%. AKI was defined as SCr increase ≥ 0.3 mg/dL or ≥ 50%. AKD evolution was evaluated 60 days post-URS. Data were analyzed using descriptive statistics. Univariable (UVA) and multivariable (MVA) logistic regression analyses tested the association of patients' characteristics and perioperative data with the occurrence of AKD.

RESULTS

Overall, postoperative AKD occurred in 32 (11.3%) patients. Recovery from AKD was found in 26 (82%) patients and persistent AKD occurred in 6 (18%) patients. At UVA, age at surgery (p = 0.05), baseline SCr (p = 0.02), baseline CKD category (p = 0.006), Charlson comorbidity index (p = 0.01), operative time (p = 0.04) and postoperative complications (< 0.001) were associated with AKD. At MVA, CKD category (OR 2.99, 95% CI = 1.4-6.3; p = 0.004), operative time (OR 1.01, 95% CI = 1.001-1.018; p = 0.023) and postoperative complications (OR 3.5, 95% CI = 1.46-8.49; p = 0.005) were independent predictors of AKD.

CONCLUSIONS

AKD is a frequent complication in patients treated with URS. Moreover, AKD persists in a non-neglectable percentage of patients at medium-term follow-up. Therefore, nephrological assessment should be considered, especially in high-risk patients. Current findings should be considered for the peri-operative management of stone patients.

Incidence and trajectories of subclinical and KDIGO-defined postoperative acute kidney injury in patients undergoing major abdominal surgery

Background

Postoperative acute kidney injury is a common occurrence among patients undergoing major abdominal surgery and is associated with adverse outcomes. The effect of an incremental increase in serum creatinine concentration not meeting the KDIGO criteria for acute kidney injury is poorly studied. We evaluated the incidence and trajectories of postoperative subclinical acute kidney injury (sPO-AKI), acute kidney injury (PO-AKI), acute kidney disease (PO-AKD), and their relationships with chronic kidney disease (CKD), major adverse kidney events (MAKE30), and all-cause mortality at 30 days after surgery.

Methods

In a pre-planned, nested cohort sub study of the Myocardial Injury in Noncardiac Surgery in Sweden (MINSS) study, we included 588 patients from two hospitals. We determined the incidence of PO-AKI, PO-AKD, and CKD according to the ADQI-POQI consensus criteria. sPO-AKI was defined as a 25-49% increase in serum creatinine concentration within 7 days of surgery.

Results

A total of 59 (10.2%) patients fulfilled the criteria for sPO-AKI, 41 (7.1%) patients for PO-AKI, 29 (6.2%) for PO-AKD, and 6 (1.2%) for CKD. Similar proportions of patients with sPO-AKI and PO-AKI developed PO-AKD. An association was identified between the combined group of sPO-AKI and PO-AKI and 30-day mortality (Cramer's V: 0.1, P=0.037). PO-AKD (Cramer's V: 0.4, P<0.001) was associated with MAKE30 and 30-day mortality. All patients with CKD had pre-existing PO-AKD.

Conclusions

Subclinical postoperative kidney injury not fulfilling the KDIGO criteria occurred in every 10th patient, and one in 14 suffered from PO-AKI after major abdominal surgery. A majority of PO-AKD cases was preceded by sPO-AKI and PO-AKI. Early kidney injuries were associated with longer-term adverse outcomes including MAKE30, 30-day mortality, and CKD.

Renal dysfunction in surgical patients

PURPOSE OF REVIEW

To provide an overview of the current diagnostic criteria for acute kidney injury (AKI) including their limitations and to discuss prevention and treatment approaches in the perioperative setting.

RECENT FINDINGS

AKI is common in the perioperative period and is associated with worse short- and long-term outcomes. Current definitions of AKI have several limitations and lead to delayed recognition of kidney dysfunction which is why novel diagnostic approaches by using renal biomarkers may be helpful. In general, prevention of the development and progression of AKI is vital as a causal treatment for AKI is currently not available. Optimization of kidney perfusion and avoidance of nephrotoxic drugs reduce the occurrence of AKI in surgical patients. Angiotensin II as a new vasopressor, the use of remote ischemic preconditioning, and amino acids may be approaches with a positive effect on the kidneys.

SUMMARY

Evidence suggests that the implementation of supportive measures in patients at high risk for AKI might reduce the occurrence of AKI. Novel biomarkers can help allocating resources by detecting patients at high risk for AKI.

Restrictive versus Decision Support Guided Fluid Therapy during Major Hepatic Resection Surgery: A Randomized Controlled Trial

BACKGROUND

Fluid therapy during major hepatic resection aims at minimizing fluids during the dissection phase to reduce central venous pressure, retrograde liver blood flow, and venous bleeding. This strategy, however, may lead to hyperlactatemia. The Acumen assisted fluid management system uses novel decision support software, the algorithm of which helps clinicians optimize fluid therapy. The study tested the hypothesis that using this decision support system could decrease arterial lactate at the end of major hepatic resection when compared to a more restrictive fluid strategy.

METHODS

This two-arm, prospective, randomized controlled, assessor- and patient-blinded superiority study included consecutive patients undergoing major liver surgery equipped with an arterial catheter linked to an uncalibrated stroke volume monitor. In the decision support group, fluid therapy was guided throughout the entire procedure using the assisted fluid management software. In the restrictive fluid group, clinicians were recommended to restrict fluid infusion to 1 to 2 ml · kg-1 · h-1 until the completion of hepatectomy. They then administered fluids based on advanced hemodynamic variables. Noradrenaline was titrated in all patients to maintain a mean arterial pressure greater than 65 mmHg. The primary outcome was arterial lactate level upon completion of surgery (i.e., skin closure).

RESULTS

A total of 90 patients were enrolled over a 7-month period. The primary outcome was lower in the decision support group than in the restrictive group (median [quartile 1 to quartile 3], 2.5 [1.9 to 3.7] mmol · l-1vs. 4.6 [3.1 to 5.4] mmol · l-1; median difference, -2.1; 95% CI, -2.7 to -1.2; P < 0.001). Among secondary exploratory outcomes, there was no difference in blood loss (median [quartile 1 to quartile 3], 450 [300 to 600] ml vs. 500 [300 to 800] ml; P = 0.727), although central venous pressure was higher in the decision support group (mean ± SD of 7.7 ± 2.0 mmHg vs. 6.6 ± 1.1 mmHg; P < 0.002).

CONCLUSIONS

Patients managed using a clinical decision support system to guide fluid administration during major hepatic resection had a lower arterial lactate concentration at the end of surgery when compared to a more restrictive fluid strategy. Future trials are necessary to make conclusive recommendations that will change clinical practice.

EDITOR’S PERSPECTIVE

Perioperative Liver and Kidney Diseases

Perioperative risks associated with acute hepatitis, cirrhosis, and chronic kidney disease are substantial and prevalence of underlying chronic kidney or liver disease is rising; surgeries in these populations have accordingly become more common. Optimal perioperative management in both cases is paramount; this article focuses on understanding disease pathophysiology, a targeted preoperative evaluation, accurate estimation of perioperative risk, and anticipation and management of common postoperative complications.

Ringer's lactate administered at 15 °C leads to a greater and more prolonged increase in blood pressure compared to 37 °C

18 Participants were randomized to receive 30 ml/kg bodyweight Ringer's Lactate at 37° or 15 °C over 30 min. In a second session, participants were crossed over. Over a 120 min period after starting the fluid bolus we measured mean arterial pressure (MAP), cardiac output, systemic vascular resistance, and catecholamine levels. After infusion with cold fluids, the absolute increase in MAP at 45 min was significantly higher at + 6.5 mmHg (95% CI 4.8-8.2) compared with warm fluids (+ 0.6 mmHg, 95% CI, - 1.6 to 2.8; p < 0.001). This increase in MAP was longer-lasting after cold fluids (81.7 min, 95% CI 62.5-100.9) than after warm fluids (19.2, 95% CI 3.4-35; p < 0.001). While cardiac output was similar, systemic vascular resistance increase was greater after cold fluids (159 dyn s/cm5, 95% CI 9.5-309) compared to warm fluids (- 66 dyn s/cm5, 95% CI - 191 to 57; p = 0.012). Moreover, noradrenaline increased by up to 246% during cold fluids, and decreased with warm fluids (p < 0.001). Fluid bolus given at 15 °C, compared to 37 °C, leads to a greater and more prolonged increase in MAP accompanied by release of intrinsic noradrenaline and vasoconstriction. These results suggest that fluid temperature rather than volume is predominantly responsible for any increase in MAP.Trial Registration: EudraCT-nummer 2022-002137-34 and clinicaltrials.gov NCT05610254 (first registration 09/11/2022).

Identifying septic shock subgroups to tailor fluid strategies through multi-omics integration

Fluid management remains a critical challenge in the treatment of septic shock, with individualized approaches lacking. This study aims to develop a statistical model based on transcriptomics to identify subgroups of septic shock patients with varied responses to fluid strategy. The study encompasses 494 septic shock patients. A benefit score is derived from the transcriptome space, with higher values indicating greater benefits from restrictive fluid strategy. Adherence to the recommended strategy is associated with a hazard ratio of 0.82 (95% confidence interval: 0.64-0.92). When applied to the baseline hospital mortality rate of 16%, adherence to the recommended fluid strategy could potentially lower this rate to 13%. A proteomic signature comprising six proteins is developed to predict the benefit score, yielding an area under the curve of 0.802 (95% confidence interval: 0.752-0.846) in classifying patients who may benefit from a restrictive strategy. In this work, we develop a proteomic signature with potential utility in guiding fluid strategy for septic shock patients.

Risk factors for postoperative acute kidney injury after radical cystectomy for bladder cancer in the era of ERAS protocols: A retrospective observational study

BACKGROUND

Radical cystectomy (RC) is a major surgery associated with a high morbidity rate. Perioperative fluid management according to enhanced recovery after surgery (ERAS) protocols aims to maintain patients in an optimal euvolemic state while exposing them to acute kidney injury (AKI) in the event of hypovolemia. Postoperative AKI is associated with severe morbidity and mortality. Our main objective was to determine the association between perioperative variables, including some component of ERAS protocols, and occurrence of postoperative AKI within the first 30 days following RC in patients presenting bladder cancer. Our secondary objective was to evaluate the association between a postoperative AKI and the occurrence or worsening of a chronic kidney disease (CKD) within the 2 years following RC.

METHODS

We conducted a retrospective observational study in a referral cancer center in France on 122 patients who underwent an elective RC for bladder cancer from 01/02/2015 to 30/09/2019. The primary endpoint was occurrence of AKI between surgery and day 30. The secondary endpoint was survival without occurrence or worsening of a postoperative CKD. AKI and CKD were defined by KDIGO (Kidney Disease: Improving Global Outcomes) classification. Logistic regression analyse was used to determine independent factors associated with postoperative AKI. Fine and Gray model was used to determine independent factors associated with postoperative CKD.

RESULTS

The incidence of postoperative AKI was 58,2% (n = 71). Multivariate analysis showed 5 factors independently associated with postoperative AKI: intraoperative restrictive vascular filling < 5ml/kg/h (OR = 4.39, 95%CI (1.05-18.39), p = 0.043), postoperative sepsis (OR = 4.61, 95%CI (1.05-20.28), p = 0.043), female sex (OR = 0.11, 95%CI (0.02-0.73), p = 0.022), score SOFA (Sequential Organ Failure Assessment) at day 1 (OR = 2.19, 95%CI (1.15-4.19), p = 0.018) and delta serum creatinine D1 (OR = 1.06, 95%CI (1.02-1.11), p = 0.006). During the entire follow-up, occurrence or worsening of CKD was diagnosed in 36 (29.5%). A postoperative, AKI was strongly associated with occurrence or worsening of a CKD within the 2 years following RC even after adjustment for confounding factors (sHR = 2.247, 95%CI [1.051-4.806, p = 0.037]).

CONCLUSION

A restrictive intraoperative vascular filling < 5ml/kg/h was strongly and independently associated with the occurrence of postoperative AKI after RC in cancer bladder patients. In this context, postoperative AKI was strongly associated with the occurrence or worsening of CKD within the 2 years following RC. A personalized perioperative fluid management strategy needs to be evaluated in these high-risk patients.

Heart failure diagnostic accuracy, intraoperative fluid management, and postoperative acute kidney injury: a single-centre prospective observational study

BACKGROUND

The accurate diagnosis of heart failure (HF) before major noncardiac surgery is frequently challenging. The impact of diagnostic accuracy for HF on intraoperative practice patterns and clinical outcomes remains unknown.

METHODS

We performed an observational study of adult patients undergoing major noncardiac surgery at an academic hospital from 2015 to 2019. A preoperative clinical diagnosis of HF was defined by keywords in the preoperative assessment or a diagnosis code. Medical records of patients with and without HF clinical diagnoses were reviewed by a multispecialty panel of physician experts to develop an adjudicated HF reference standard. The exposure of interest was an adjudicated diagnosis of heart failure. The primary outcome was volume of intraoperative fluid administered. The secondary outcome was postoperative acute kidney injury (AKI).

RESULTS

From 40 659 surgeries, a stratified subsample of 1018 patients were reviewed by a physician panel. Among patients with adjudicated diagnoses of HF, those without a clinical diagnosis (false negatives) more commonly had preserved left ventricular ejection fractions and fewer comorbidities. Compared with false negatives, an accurate diagnosis of HF (true positives) was associated with 470 ml (95% confidence interval: 120-830; P=0.009) lower intraoperative fluid administration and lower risk of AKI (adjusted odds ratio:0.39, 95% confidence interval 0.18-0.89). For patients without adjudicated diagnoses of HF, non-HF was not associated with differences in either fluids administered or AKI.

CONCLUSIONS

An accurate preoperative diagnosis of heart failure before noncardiac surgery is associated with reduced intraoperative fluid administration and less acute kidney injury. Targeted efforts to improve preoperative diagnostic accuracy for heart failure may improve perioperative outcomes.

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.

Intraoperative Fluid Balance and Perioperative Complications in Ovarian Cancer Surgery

BACKGROUND

Fluid overload and hypovolemia promote postoperative complications in patients undergoing cytoreductive surgery for ovarian cancer. In the present study, postoperative complications and anastomotic leakage were investigated before and after implementation of pulse pressure variation-guided fluid management (PPVGFM) during ovarian cancer surgery.

PATIENTS AND METHODS

A total of n = 243 patients with ovarian cancer undergoing cytoreductive surgery at the University Hospital Bonn were retrospectively evaluated. Cohort A (CA; n = 185 patients) was treated before and cohort B (CB; n = 58 patients) after implementation of PPVGFM. Both cohorts were compared regarding postoperative complications.

RESULTS

Ultrasevere complications (G4/G5) were exclusively present in CA (p = 0.0025). No difference between cohorts was observed regarding severe complications (G3-G5) (p = 0.062). Median positive fluid excess was lower in CB (p = 0.001). This was independent of tumor load [peritoneal cancer index] (p = 0.001) and FIGO stage (p = 0.001). Time to first postoperative defecation was shorter in CB (CB: d2 median versus CA: d3 median; p = 0.001). CB had a shorter length of hospital stay (p = 0.003), less requirement of intensive medical care (p = 0.001) and postoperative ventilation (p = 0.001). CB received higher doses of noradrenalin (p = 0.001). In the combined study cohort, there were more severe complications (G3-G5) in the case of a PFE ≥ 3000 ml (p = 0.034) and significantly more anastomotic leakage in the case of a PFE ≥ 4000 ml (p = 0.006).

CONCLUSIONS

Intraoperative fluid reduction in ovarian cancer surgery according to a PPVGFM is safe and significantly reduces ultrasevere postoperative complications. PFEs of ≥ 3000 ml and ≥ 4000 ml were identified as cutoffs for significantly more severe complications and anastomotic leakage, respectively.

Comparison of 4% Albumin and Ringer's Acetate on Hemodynamics in On-pump Cardiac Surgery: An Exploratory Analysis of a Randomized Clinical Trial

OBJECTIVES

Compare hemodynamics between 4% albumin and Ringer's acetate.

DESIGN

Exploratory analysis of the double-blind randomized ALBumin In Cardiac Surgery trial.

SETTING

Single-center study in Helsinki University Hospital.

PARTICIPANTS

We included 1,386 on-pump cardiac surgical patients.

INTERVENTION

We used 4% albumin or Ringer's acetate administration for cardiopulmonary bypass priming, volume replacement intraoperatively and 24 hours postoperatively.

MEASUREMENTS AND MAIN RESULTS

Hypotension (time-weighted average mean arterial pressure of <65 mmHg) and hyperlactatemia (time-weighted average blood lactate of >2 mmol/L) incidences were compared between trial groups in the operating room (OR), and early (0-6 hours) and late (6-24 hours) postoperatively. Associations of hypotension and hyperlactatemia with the ALBumin In Cardiac Surgery primary outcome (≥1 major adverse event [MAE]) were studied. In these time intervals, hypotension occurred in 118, 48, and 17 patients, and hyperlactatemia in 313, 131, and 83 patients. Hypotension and hyperlactatemia associated with MAE occurrence. Hypotension did not differ between the groups (albumin vs Ringer's: OR, 8.8% vs 8.5%; early postoperatively, 2.7% vs 4.2%; late postoperatively, 1.2% vs 1.3%; all p > 0.05). In the albumin group, hyperlactatemia was less frequent late postoperatively (2.9% vs 9.1%; p < 0.001), but not earlier (OR, 22.4% vs 23.6%; early postoperatively, 7.9% vs 11.0%; both p > 0.025 after Bonferroni-Holm correction).

CONCLUSIONS

In on-pump cardiac surgery, hypotension and hyperlactatemia are associated with the occurrence of ≥1 MAE. Compared with Ringer's acetate, albumin did not decrease hypotension and decreased hyperlactatemia only late postoperatively. Albumin's modest hemodynamic effect is concordant with the finding of no difference in MAEs between albumin and Ringer's acetate in the ALBumin In Cardiac Surgery trial.

Perioperative fluid management: evidence-based consensus recommendations from the international multidisciplinary PeriOperative Quality Initiative

Fluid therapy is an integral component of perioperative management. In light of emerging evidence in this area, the Perioperative Quality Initiative (POQI) convened an international multiprofessional expert meeting to generate evidence-based consensus recommendations for fluid management in patients undergoing surgery. This article provides a summary of the recommendations for perioperative fluid management of surgical patients from the preoperative period until hospital discharge and for all types of elective and emergency surgery, apart from burn injuries and head and neck surgery. Where evidence was lacking, recommendations for future research were generated. Specific recommendations are made for fluid management in elective major noncardiac surgery, cardiopulmonary bypass, thoracic surgery, neurosurgery, minor noncardiac surgery under general anaesthesia, and critical illness. There are ongoing gaps in knowledge resulting in variation in practice and some disagreement with our consensus recommendations. Perioperative fluid management should be individualised, taking into account the type of surgery and important patient factors, including intravascular volume status and acute and chronic comorbidities. Recommendations are made for further research in perioperative fluid management to address important gaps.

The effect of intraoperative goal-directed fluid therapy in patients under anesthesia for gastrointestinal surgery

BACKGROUND

Intraoperative fluid management is an important aspect of anesthesia management in gastrointestinal surgery. Intraoperative goal-directed fluid therapy (GDFT) is a method for optimizing a patient's physiological state by monitoring and regulating fluid input in real-time.

AIM

To evaluate the efficacy of intraoperative GDFT in patients under anesthesia for gastrointestinal surgery.

METHODS

This study utilized a retrospective comparative study design and included 60 patients who underwent gastrointestinal surgery at a hospital. The experimental group (GDFT group) and the control group, each comprising 30 patients, received intraoperative GDFT and traditional fluid management strategies, respectively. The effect of GDFT was evaluated by comparing postoperative recovery, complication rates, hospitalization time, and other indicators between the two patient groups.

RESULTS

Intraoperative blood loss in the experimental and control groups was 296.64 ± 46.71 mL and 470.05 ± 73.26 mL (P < 0.001), and urine volume was 415.13 ± 96.72 mL and 239.15 ± 94.69 mL (P < 0.001), respectively. The postoperative recovery time was 5.44 ± 1.1 days for the experimental group compared to 7.59 ± 1.45 days (P < 0.001) for the control group. Hospitalization time for the experimental group was 10.87 ± 2.36 days vs 13.65 ± 3 days for the control group (P < 0.001). The visual analogue scale scores of the experimental and control groups at 24 h and 48 h post-surgery were 3.38 ± 0.79 and 4.51 ± 0.86, and 2.05 ± 0.57 and 3.51 ± 0.97 (P < 0.001), respectively. The cardiac output of the experimental and control groups was 5.99 ± 1.04 L/min and 4.88 ± 1.17 L/min, respectively, while the pulse pressure variability for these two groups was 10.87 ± 2.36% and 17.5 ± 3.21%, respectively.

CONCLUSION

The application of GDFT in gastrointestinal surgery can significantly improve postoperative recovery, reduce the incidence of complications, and shorten hospital stays.

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.

Acute kidney injury in the acute care surgery patient: What you need to know

ABSTRACT

Acute kidney injury is associated with poor outcomes in the trauma and emergency general surgery population, and recent consensus definitions have allowed for significant advances in defining the burden of disease. The current definitions rely on overall functional measures (i.e., serum creatinine and urine output), which can be confounded by a variety of clinical factors. Biomarkers are increasingly being investigated as more direct diagnostic assays for the diagnosis of acute kidney injury and may allow earlier detection and more timely therapeutic intervention. Etiologies fall into two general categories: disorders of renal perfusion and exposure to nephrotoxic agents. Therapy is largely supportive, and prevention offers the best chance to decrease clinical impact.

Effect of rigorous fluid management using monitoring of ECW ratio by bioelectrical impedance analysis in critically ill postoperative patients: A prospective, single-blind, randomized controlled study

BACKGROUND & AIMS

Precise assessment of postoperative volume status is important to administrate optimal fluid management. Bioelectrical impedance analysis (BIA) which measures the body composition using electric character. Extracellular water (ECW) ratio by BIA represented as the ratio of ECW to total body water (TBW) and is known to reflect the hydration status. Based on this, we aimed to determine whether aggressive fluid control using ECW ratio could improve clinical outcomes through a single blind, randomized controlled trial.

METHODS

From November 2021 to December 2022, intensive care unit (ICU) patients admitted after surgery were randomly assigned to an intervention group or a control group whether postoperative fluid management was controlled via BIA. Among patients in the intervention group, dehydrated patients received a bolus infusion with crystalloid fluid whereas diuretics were administrated to overhydrated patients until the value of ECW ratio fell within its normal setting range (0.390-0.406). Contrarily, BIA was performed once a day for the control group. Patients in the control group received traditional fluid treatment regardless of BIA results. Primary outcome was in-hospital mortality in two groups. The secondary outcomes were postoperative morbidities, 28-day mortality.

RESULTS

77 patients of the intervention group and 90 patients of the control group were finally analyzed. The in-hospital mortality (0 in intervention, 4.4% in control, p = 0.125) and 28-day mortality (1.3% in intervention, 14.4% in control, p = 0.002) showed lower incidence in the intervention group than in the control group. In multivariate analysis, the overhydrated status whose ECW ratio exceeding 0.406 [odds ratio (OR): 2.731, 95% confidence interval (CI): 1.001-7.663, p = 0.049] and high capillary leak index (CLI) value at ICU admission (OR: 1.024, 95% CI: 1.008-1.039, p = 0.002) were risk factors of postoperative morbidities. Regarding the 28-day mortality, high CLI value (OR: 1.025, 95% CI: 1.002-1.050, p = 0.037) and traditional strategy without BIA monitoring (OR: 9.903, 95% CI: 1.095-89.566, p = 0.041) were the significant predisposing factors.

CONCLUSION

Our results revealed the rigorous fluid treatment with volume control based on ECW ratio by BIA failed to achieve significant improvement in in-hospital mortality, but it could reduce 28-day mortality of ICU patients. Monitoring of ECW ratio may help establish optimal fluid treatment strategies for postoperative ICU patients who are susceptible to fluid imbalances with fluid overload.

TRIAL REGISTRATION

ClinicalTrials.gov, NCT06097923, retrospectively registered on October 16, 2023, https://clinicaltrials.gov/study/NCT06097923?term=NCT06097923&rank=1.

Role of Peripheral Parenteral Nutrition Composition on Clinical Outcomes in Patients Undergoing Gastrectomy or Colectomy: A Phase III Indian Clinical Trial

Aims and background

Various types of parenteral nutritional products exist, each with specific formulations designed to meet the diverse nutritional needs of patient's post-abdominal surgery. Here, two different parenteral nutrition (PN) solutions BFLUID and NUTRIFLEX PERI are compared in terms of therapeutic efficacy and safety profile.

Materials and methods

A prospective, multi-center, randomized, parallel-group, non-inferiority Phase III clinical trial compared two PN solutions namely BFLUID (N = 78) and NUTRIFLEX PERI (N = 72) in 150 patients undergoing gastrectomy or colectomy. Primary endpoints included length of hospital stay while secondary endpoints included assessment and comparison of length of ICU/HDU stay, assessment of incidents of infections and mortality, change in blood levels of vitamin B1, change in nutritional parameters, thrombophlebitis, pain at the injection site, and recording of adverse events (AEs).

Results

There was no significant difference in terms of length of hospital stay, length of ICU/HDU stay as well as changes in nutritional parameters from baseline and change in blood levels of vitamin B1 from baseline. Both study groups exhibited comparability in terms of AEs, pain at the injection site, and the incidence of phlebitis. There was no significant difference in the number and severity of adverse events reported in both groups. Additionally, no signs of infection were observed in patients from either group.

Conclusion

The trial successfully demonstrated the non-inferiority of BFLUID to NUTRIFLEX PERI. Moreover, the results indicated that PN enriched with high levels of branched-chain amino acids (BCAAs), essential amino acids (EAAs), and thiamine is both safe and efficacious for adult patients undergoing gastrectomy or colectomy.

How to cite this article

Goyal A, Pathak A, BS Madhu, Soni H, Bhatt K, Raju KVVN, et al. Role of Peripheral Parenteral Nutrition Composition on Clinical Outcomes in Patients Undergoing Gastrectomy or Colectomy: A Phase III Indian Clinical Trial. Indian J Crit Care Med 2024;28(9):871-878.

Predictive modelling for postoperative acute kidney injury: big data enhancing quality or the Emperor's new clothes?

The increased availability of large clinical datasets together with increasingly sophisticated computing power has facilitated development of numerous risk prediction models for various adverse perioperative outcomes, including acute kidney injury (AKI). The rationale for developing such models is straightforward. However, despite numerous purported benefits, the uptake of preoperative prediction models into clinical practice has been limited. Barriers to implementation of predictive models, including limitations in their discrimination and accuracy, as well as their ability to meaningfully impact clinical practice and patient outcomes, are increasingly recognised. Some of the purported benefits of predictive modelling, particularly when applied to postoperative AKI, might not fare well under detailed scrutiny. Future research should address existing limitations and seek to demonstrate both benefit to patients and value to healthcare systems from implementation of these models in clinical practice.

High intraoperative fluid load associated with prolonged length of hospital stay and complications after non-cardiac surgery in neonates

Inappropriate perioperative fluid load can lead to postoperative complications and death. This retrospective study was designed to investigate the association between intraoperative fluid load and outcomes in neonates undergoing non-cardiac surgery. From April 2020 to September 2022, 940 neonates who underwent non-cardiac surgery were retrospectively enrolled and their perioperative data were harvested for further analysis. According to recorded intraoperative fluid volumes defined as ml.kg-1 h-1, patients were mandatorily divided into quintile with fluid load as restrictive (quintile 1, Q1), moderately restrictive (Q2), moderate (Q3), moderately liberal (Q4), and liberal (Q5). The primary outcomes were defined as prolonged length of hospital stay (LOS) (postoperative LOS ≥ 14 days), complications beyond prolonged LOS, and 30-day mortality. Secondary outcomes included postoperative complications within 14 days of hospital stay. The intraoperative fluid load was in Q1 of 6.5 (5.3-7.3) (median and IQR); Q2: 9.2 (8.7-9.9); Q3: 12.2 (11.4-13.2); Q4: 16.5 (15.4-18.0); and Q5: 26.5 (22.3-32.2) ml.kg-1 h-1. The odd of prolonged LOS was positively correlated with an increase fluid volume (Q5 quintile: OR 2.602 [95% CI 1.444-4.690], P = 0.001), as well as complications beyond prolonged LOS (Q5: OR 3.322 [95% CI 1.656-6.275], P = 0.001). The overall 30-day mortality rate was increased with high intraoperative fluid load but did not reach to a statistical significance after adjusted with confounders. Furthermore, the highest quintile of fluid load (26.5 ml.kg-1 h-1, IQR [22.3-32.2]) (Q5 quintile) was significantly associated with longer postoperative mechanical ventilation time compared with Q1 (Q5: OR 2.212 [95% CI 1.101-4.445], P = 0.026).    Conclusion: Restrictive intraoperative fluid load had overall better outcomes, whilst high fluid load was significantly associated with prolonged LOS and complications after non-cardiac surgery in neonates.    Trial registration:  Chictr.org.cn Identifier: ChiCTR2200066823 (December 19, 2022). What is Known: • Inappropriate perioperative fluid load can lead to postoperative complications and even death. What is New: • High perioperative fluid load was significantly associated with an increased length of stay after non-cardiac surgery in neonates, whilst low fluid load was consistently related to better postoperative outcomes.

Understanding fluid dynamics and renal perfusion in acute kidney injury management

Acute kidney injury (AKI) is associated with an increased risk of morbidity, mortality, and healthcare expenditure, posing a major challenge in clinical practice, and affecting about 50% of patients in the intensive care unit (ICU), particularly the elderly and those with pre-existing chronic comorbidities. In health, intra-renal blood flow is maintained and auto-regulated within a wide range of renal perfusion pressures (60-100 mmHg), mediated predominantly through changes in pre-glomerular vascular tone of the afferent arteriole in response to changes of the intratubular NaCl concentration, i.e. tubuloglomerular feedback. Several neurohormonal processes contribute to regulation of the renal microcirculation, including the sympathetic nervous system, vasodilators such as nitric oxide and prostaglandin E2, and vasoconstrictors such as endothelin, angiotensin II and adenosine. The most common risk factors for AKI include volume depletion, haemodynamic instability, inflammation, nephrotoxic exposure and mitochondrial dysfunction. Fluid management is an essential component of AKI prevention and management. While traditional approaches emphasize fluid resuscitation to ensure renal perfusion, recent evidence urges caution against excessive fluid administration, given AKI patients' susceptibility to volume overload. This review examines the main characteristics of AKI in ICU patients and provides guidance on fluid management, use of biomarkers, and pharmacological strategies.

Applying enhanced recovery after surgery protocols in a patient with a giant spleen: a case report

Although splenomegaly is a common finding in several diseases, massive splenomegaly is rare. Patients with massive splenomegaly often present with a complex clinical picture. This case report describes a 72-year-old female with a complex medical history. Fifteen years ago, she was diagnosed with primary myelofibrosis, which subsequently led to progressive abdominal enlargement and bloating over the past 5 years. Recently, she developed edema in her limbs, accompanied by dizziness, shortness of breath, and fatigue. A massive splenomegaly was discovered during her hospitalization. Additionally, the patient has a history of Crohn's disease, gout, renal insufficiency, and hypertension. Laboratory results reveal severe anemia and thrombocytopenia. Abdominal CT scans confirm the enlarged spleen and show ascites. She was treated by a multidisciplinary team comprising several departments. Even after a period of comprehensive treatment, the symptoms of massive splenomegaly did not significantly improve. Thus, the patient underwent an open surgical excision of the giant spleen. The weight of the giant spleen was 5.0 kg. During the perioperative period, Enhanced Recovery After Surgery (ERAS) protocols were applied to facilitate recovery. Her recovery was uneventful, and she was able to resume her regular daily routine shortly after the procedure. This report presented a complex and rare case of massive splenomegaly, and underscored that a proper medical and nursing care is the key to better recovery.

Myocardial strain is regulated by cardiac preload in the early stage of sepsis

BACKGROUND

Owing to a lack of data, this study aimed to explore the effect of cardiac preload on myocardial strain in patients with sepsis.

METHODS

A total of 70 patients with sepsis in intensive care unit (ICU) of a tertiary teaching hospital in China from January 2018 to July 2019 and underwent transthoracic echocardiography were enrolled. Echocardiographic data were recorded at ICU admission and 24 h later. Patients were assigned to low left ventricular end-diastolic volume index (LVEDVI) and normal LVEDVI groups. We assessed the impact of preload on myocardial strain between the groups and analyzed the correlation of echocardiographic parameters under different preload conditions.

RESULTS

Thirty-seven patients (53%) had a low LVEDVI and 33 (47%) a normal LVEDVI. Those in the low LVEDVI group had a faster heart rate (121.7 vs. 95.3, p < 0.001) and required a greater degree of fluid infusion (3.67 L vs. 2.62 L, P = 0.019). The left ventricular global strain (LVGLS) (-8.60% vs. -10.80%, p = 0.001), left ventricular global circumferential strain (LVGCS) (-13.83% vs. -18.26%, p = 0.006), and right ventricular global longitudinal strain (RVGLS) (-6.9% vs. -10.60%, p = 0.001) showed significant improvements in the low LVEDVI group after fluid resuscitation. However, fluid resuscitation resulted in a significantly increased cardiac afterload value (1172.00 vs. 1487.00, p = 0.009) only in the normal LVEDVI group. Multivariate backward linear regression showed that LVEDVI changes were independently associated with myocardial strain-related improvements during fluid resuscitation. The baseline LVEDVI was significantly negatively correlated with the LVGLS and RVGLS (r = -0.44 and - 0.39, respectively) but not LVGCS. LVEDVI increases during fluid resuscitation were associated with improvements in the myocardial strain degree.

CONCLUSIONS

Myocardial strain alterations were significantly influenced by the cardiac preload during fluid resuscitation in sepsis.

The effect of high-volume intraoperative fluid administration on outcomes among pediatric patients undergoing living donor liver transplantation

BACKGROUND

Pediatric patients undergoing liver transplantation are particularly susceptible to complications arising from intraoperative fluid management strategies. Conventional liberal fluid administration has been challenged due to its association with increased perioperative morbidity. This study aimed to assess the impact of intraoperative high-volume fluid therapy on pediatric patients who are undergoing living donor liver transplantation (LDLT).

METHODS

Conducted at the Children's Hospital of Chongqing Medical University from March 2018 to April 2021, this retrospective study involved 90 pediatric patients divided into high-volume and non-high-volume fluid administration groups based on the 80th percentile of fluid administered. We collected the perioperative parameters and postoperative information of two groups. Multivariable logistic regression was utilized to assess the association between estimated blood loss (EBL) and high-volume FA. Kaplan-Meier survival analysis was used to compare patient survival after pediatric LDLT.

RESULTS

Patients in the high-volume FA group received a higher EBL and longer length of stay than that in the non-high-volume FA group. Multivariate logistic regression analysis indicated that hours of maintenance fluids and fresh frozen plasma were significantly associated risk factors for the occurrence of EBL during pediatric LDLT. In addition, survival analysis showed no significant differences in one-year mortality between the groups.

CONCLUSIONS

High-volume fluid administration during LDLT is linked with poorer intraoperative and postoperative outcomes among pediatric patients. These findings underscore the need for more conservative fluid management strategies in pediatric liver transplantations to enhance recovery and reduce complications.

Transitions from Aerobic to Anaerobic Metabolism and Oxygen Debt during Elective Major and Emergency Non-Cardiac Surgery

INTRODUCTION

Intraoperative hemodynamic and metabolic optimization of both the high-risk surgical patients and critically ill patients remains challenging. Reductions in oxygen delivery or increases in oxygen consumption can initiate complex cellular processes precipitating oxygen debt (OXD).

METHODS

This study tested the hypothesis that intraoperative changes in sublingual microcirculatory flow reflect clinically relevant transitions from aerobic to anaerobic metabolism (TRANAM). We included patients undergoing elective major and emergency non-cardiac surgery. Macro- and microcirculatory variables, oxygen extraction, and transitions of metabolism were assessed in both cohorts.

RESULTS

In the elective group, OXD was progressively increased over time, with an estimated 2.24 unit increase every 30 min (adjusted p < 0.001). Also, OXD was negatively correlated with central venous pressure (ρ = -0.247, adjusted p = 0.006) and positively correlated with stroke volume variation (ρ = 0.185, adjusted p = 0.041). However, it was not significantly correlated with sublingual microcirculation variables. In the emergency surgery group, OXD increased during the first two intraoperative hours and then gradually decreased until the end of surgery. In that cohort, OXD was positively correlated with diastolic arterial pressure (ρ = 0.338, adjpatients and the critically ill patients remains challengingsted p = 0.015). Also, OXD was negatively correlated with cardiac index (ρ = -0.352, adjusted p = 0.003), Consensus Proportion of Perfused Vessels (PPV) (ρ = -0.438, adjusted p < 0.001), and Consensus PPV (small) (ρ = -0.434, adjusted p < 0.001).

CONCLUSIONS

TRANAM were evident in both the elective major and emergency non-cardiac surgery cohorts independent of underlying alterations in the sublingual microcirculation.

Individualising goal-directed haemodynamic therapy: future iterations will require novel trial designs

Variants of perioperative cardiac output-guided haemodynamic therapy algorithms have been tested over the last few decades, without clear evidence of effectiveness. Newer approaches have focussed on individualisation of physiological targets and have been tested in early efficacy trials. Uncertainty about the benefits remains. Adoption of novel trial designs could overcome the limitations of smaller trials of this complex intervention and accelerate the exploration of future developments.

Biomarker-guided acute kidney injury risk assessment under liberal versus restrictive fluid therapy - the prospective-randomized MAYDAY-trial

Acute kidney injury (AKI) prevalence in surgical patients is high, emphasizing the need for preventative measures. This study addresses the insufficient evidence on nephroprotective intraoperative fluid resuscitation and highlights the drawbacks of relying solely on serum creatinine/urine output to monitor kidney function. This study assessed the impact of intraoperative fluid management on AKI in female breast cancer patients undergoing autologous breast reconstruction, utilizing novel urinary biomarkers (TIMP-2 and IGFBP-7). In a monocentric prospective randomized controlled trial involving 40 patients, liberal (LFA) and restrictive (FRV) fluid management strategies were compared. TIMP-2 and IGFBP-7 biomarker levels were assessed using the NephroCheck (bioMerieux, France) test kit at preoperative, immediate postoperative, and 24-h postoperative stages. FRV showed significantly higher immediate postoperative biomarker levels, indicating renal tubular stress. FRV patients had 21% (4/19) experiencing AKI compared to 13% (2/15) in the LFA group according to KDIGO criteria (p = 0.385). Restrictive fluid resuscitation increases the risk of AKI in surgical patients significantly, emphasizing the necessity for individualized hemodynamic management. The findings underscore the importance of urinary biomarkers in early AKI detection.

Crystalloid volume versus catecholamines for management of hemorrhagic shock during esophagectomy - assessment of microcirculatory tissue oxygenation of the gastric conduit in a porcine model using hyperspectral imaging - an experimental study

INTRODUCTION

Oncologic esophagectomy is a two-cavity procedure with considerable morbidity and mortality. Complex anatomy and the proximity to major vessels constitute a risk for massive intraoperative hemorrhage. Currently, there is no conclusive consensus on the ideal anesthesiologic countermeasure in case of such immense blood loss. The objective of this work was to identify the most promising anesthesiologic management in case of intraoperative hemorrhage with regards to tissue perfusion of the gastric conduit during esophagectomy using hyperspectral imaging (HSI).

MATERIAL AND METHODS

An established live porcine model (n=32) for esophagectomy was used with gastric conduit formation and simulation of a linear stapled side-to-side esophagogastrostomy. After a standardized procedure of controlled blood loss of about 1 L per pig, the four experimental groups (n=8 each) differed in anesthesiologic intervention i.e. (I) permissive hypotension, (II) catecholamine therapy using noradrenaline, (III) crystalloid volume supplementation and (IV) combined crystalloid volume supplementation with noradrenaline therapy. HSI tissue oxygenation (StO2) of the gastric conduit was evaluated and correlated with systemic perfusion parameters. Measurements were conducted before (T0) and after (T1) laparotomy, after hemorrhage (T2) and 60 minutes (T3) and 120 minutes (T4) after anesthesiologic intervention.

RESULTS

StO2 values of the gastric conduit showed significantly different results between the four experimental groups with 63.3% (±7.6%) after permissive hypotension (I), 45.9% (±6.4%) after catecholamine therapy (II), 70.5% (±6.1%) after crystalloid volume supplementation (III) and 69.0% (±3.7%) after combined therapy (IV). StO2 values correlated strongly with systemic lactate values (r=-0.67; CI -0.77 to -0.54), which is an established prognostic factor.

CONCLUSION

Crystalloid volume supplementation (III) yields the highest StO2 values and lowest systemic lactate values and therefore appears to be the superior primary treatment strategy after hemorrhage during esophagectomy with regards to microcirculatory tissue oxygenation of the gastric conduit.

Intraoperative fluid management is not predictive of AKI in major pancreatic surgery: a retrospective cohort study

BACKGROUND

Pancreatic surgery is associated with a significant risk for acute kidney injury (AKI) and clinically relevant postoperative pancreatic fistula (CR-POPF). This investigation evaluated the impact of intraoperative volume administration, vasopressor therapy, and blood pressure management on the primary outcome of AKI and the secondary outcome of a CR-POPF after pancreatic surgery.

METHODS

This retrospective single-center cohort investigated 200 consecutive pancreatic surgeries (January 2018-December 2021). Patients were categorized for the presence/absence of AKI (Kidney Disease Improving Global Outcomes) and CR-POPF. After univariate analysis, multivariable models were constructed to control for the univariate cofactor differences in the primary and secondary outcomes.

RESULTS

AKI was identified in 20 patients (10%) with significant univariate differences in demographics (body mass index and gender), comorbidities, indices of chronic renal insufficiency, and an increased AKI Risk score. Surgical characteristics, intraoperative fluid, vasopressor, and blood pressure management were similar in patients with and without AKI. Patients with AKI had increased blood loss, lower urine output, and packed red blood cell administration. After multivariate analysis, male gender (OR = 7.9, 95% C.I. 1.8-35.1) and the AKI Risk score (OR = 6.3, 95% C.I. 2.4-16.4) were associated with the development of AKI (p < 0.001). Intraoperative and postoperative volume, vasopressor administration, and intraoperative hypotension had no significant impact in the multivariate analysis. CR-POPF occurred in 23 patients (11.9%) with no significant contributing factors in the multivariate analysis. Patients who developed AKI or a CR-POPF had an increase in surgical complications, length of stay, discharge to a skilled nursing facility, and mortality.

CONCLUSION

In this analysis, intraoperative volume administration, vasopressor therapy, and a blood pressure < 55 mmHg for more than 10 min were not associated with an increased risk of AKI. After multivariate analysis, male gender and an elevated AKI Risk score were associated with an increased likelihood of AKI.

Anesthesia-induced Lymphatic Dysfunction

General anesthetics adversely alters the distribution of infused fluid between the plasma compartment and the extravascular space. This maldistribution occurs largely from the effects of anesthetic agents on lymphatic pumping, which can be demonstrated by macroscopic fluid kinetics studies in awake versus anesthetized patients. The magnitude of this effect can be appreciated as follows: a 30% reduction in lymph flow may result in a fivefold increase of fluid-induced volume expansion of the interstitial space relative to plasma volume. Anesthesia-induced lymphatic dysfunction is a key factor why anesthetized patients require greater than expected fluid administration than can be accounted for by blood loss, urine output, and insensible losses. Anesthesia also blunts the transvascular refill response to bleeding, an important compensatory mechanism during hemorrhagic hypovolemia, in part through lymphatic inhibition. Last, this study addresses how catecholamines and hypertonic and hyperoncotic fluids may mobilize interstitial fluid to mitigate anesthesia-induced lymphatic dysfunction.

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.

Influence of Intraoperative Fluid Management on Postoperative Outcome and Mortality of Cytoreductive Surgery for Advanced Ovarian Cancer-A Retrospective Observational Study

Background: The surgical treatment of advanced ovarian cancer is associated with extensive tissue trauma, prolonged operating times and a considerable volume shift. It, therefore, represents a challenge for anaesthesiological management. Aim: The aim of this single-centre, retrospective, observational study was to investigate whether intraoperative extensive volume supply influences postoperative outcomes and long-term survival. Methods: The study included 73 patients with a mean (SD) age of 63 (13) years who underwent extensive tumour-reducing surgery for ovarian cancer between 2012 and 2015. The effect of the intraoperative fluid balance on postoperative complications, such as anastomotic insufficiency or pleural effusions, was investigated using logistic regression. Further, the influence of fluid balance, lactate and creatinine levels on 5-year survival was analysed in a Cox regression model. Associations between anaesthesia time and the intraoperative fluid balance were examined using Spearman's rank correlation coefficients. Results: The mean (SD) postoperative fluid balance in the considered patient cohort was 9.1 (3.4) litres (l) at a mean (SD) anaesthesia time of 529 (106) minutes. Cox regression did not reveal a statistically significant effect of the fluid balance, but it did reveal a statistically significant association between the lactate level 24 h following surgery and the 5-year survival (HR [95%-CI] fluid balance: 0.97 [0.85, 1.11]; HR [95%-CI] lactate: 1.79 [1.24, 2.58]). According to logistic regression, the intraoperative fluid balance was associated with an increased chance of postoperative complications in the considered patient cohort (OR [95%-CI] 1.28 [1.1, 1.54]). Conclusions: We could not detect a negative impact of an increased fluid balance on 5-year survival, but a negative impact on postoperative complications was found in our patient cohort.

Acute kidney injury after radical gastrectomy: incidence, risk factors, and impact on prognosis

Background

Acute kidney injury (AKI) is a serious adverse event often overlooked following major abdominal surgery. While radical gastrectomy stands as the primary curative method for treating gastric cancer patients, little information exists regarding AKI post-surgery. Hence, this study aimed to ascertain the incidence rate, risk factors, and consequences of AKI among patients undergoing radical gastrectomy.

Methods

This was a population-based, retrospective cohort study. The incidence of AKI was calculated. Multivariate logistic regression was used to identify independent predictors of AKI. Survival curves were plotted by using the Kaplan-Meier method and differences in survival rates between groups were analyzed by using the log-rank test.

Results

Of the 2,875 patients enrolled in this study, 61 (2.1%) developed postoperative AKI, with AKI Network 1, 2, and 3 in 50 (82.0%), 6 (9.8%), and 5 (8.2%), respectively. Of these, 49 patients had fully recovered by discharge. Risk factors for AKI after radical gastrectomy were preoperative hypertension (odds ratio [OR], 1.877; 95% CI, 1.064-3.311; P = 0.030), intraoperative blood loss (OR, 1.001; 95% CI, 1.000-1.002; P = 0.023), operation time (OR, 1.303; 95% CI, 1.030-1.649; P = 0.027), and postoperative intensive care unit (ICU) admission (OR, 4.303; 95% CI, 2.301-8.045; P < 0.001). The probability of postoperative complications, mortality during hospitalization, and length of stay in patients with AKI after surgery were significantly higher than those in patients without AKI. There was no statistical difference in overall survival (OS) rates between patients with AKI and without AKI (1-year, 3-year, 5-year overall survival rates of patients with AKI and without AKI were 93.3% vs 92.0%, 70.9% vs 73.6%, and 57.1% vs 67.1%, respectively, P = 0.137).

Conclusions

AKI following radical gastrectomy is relatively rare and typically self-limited. AKI is linked with preoperative hypertension, intraoperative blood loss, operation time, and postoperative ICU admission. While AKI raises the likelihood of postoperative complications, it does not affect OS.

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

Incidence of acute kidney injury and its associated risk factors in patients undergoing elective oesophagectomy surgeries at a tertiary care cancer institute - A pilot prospective observational study

Background and Aims

Acute kidney injury (AKI) is a significant postoperative complication. Multiple perioperative factors are implicated in the causation of AKI in the postoperative period in patients with oesophageal cancer. The study aimed to find out the incidence, causes and effects of AKI following oesophagectomy surgery.

Methods

A prospective observational study was conducted in consecutive adult patients undergoing elective oesophagectomy at a tertiary cancer care hospital. Patients with preoperative chronic renal insufficiency (serum creatinine >1.5 mg/dl), AKI in the past and a history of renal replacement therapy were excluded. Serum creatinine values were measured on postoperative days 1, 3, 5, the day of discharge or day 15 and on the day of first follow-up or day 28, following oesophagectomy surgery. The incidence of AKI was measured using the 'Kidney Disease Improving Global Outcome' (KDIGO) criteria.

Results

The incidence of AKI was 14.7% [95% confidence interval (CI) 9.9%, 20.7%] (i.e., 27/183) in patients who underwent elective oesophagectomy. AKI was associated with prolonged hospital stay [median- 13 days (interquartile range {IQR} 11-21.5) versus 9 days (IQR 8-12), P < 0.001] and increased in-hospital mortality (14.8% versus 1.3%, P 0.004, odds ratio = 13.2, 95% CI 2.3, 77.3). After multivariate analysis, age, anastomotic leak and use of vasopressors in the postoperative period were independent predictors of AKI.

Conclusion

The incidence of AKI was 14.7% after elective oesophagectomy. AKI was associated with prolonged hospital stay and in-hospital mortality. Higher age, anastomotic leak and use of vasopressors in the postoperative period were independent predictors of AKI.

Impact of fluid balance and opioid-sparing anesthesia within enchanced recovery pathway on postoperative morbidity after transthoracic esophagectomy for cancer

Background

Enhanced Recovery After Surgery (ERAS) protocol for esophagectomy may reduce the high incidence of postoperative morbidity and mortality. The aim of this study was to assess the impact of properly conducted ERAS protocol with specific emphasis on fluid balance and opioid-sparing anesthesia (OSA) on postoperative major morbidity and mortality after esophagectomy.

Methods

Patients undergoing elective esophagectomy for esophageal cancer at the Hospital for Digestive Surgery, University Clinical Center of Serbia, from December 2017 to March 2021, were included in this retrospective observational study. Patients were divided into two groups: the ERAS group (OSA, intraoperative goal-directed therapy, and postoperative “near-zero” fluid balance) and the control group (opioid-based anesthesia, maintenance mean blood pressure ≥ 65 mmHg, and liberal postoperative fluid management). The primary outcome was major morbidity within 30 days from surgery and 30-day and 90-day mortality. Multivariable analysis was used to examine the effect of the ERAS protocol.

Results

A total of 121 patients were divided into the ERAS group (69 patients) and the control group (52 patients). Patients in the ERAS group was received less fentanyl, median 300 (interquartile range (IQR), 200–1,550) mcg than in control group, median 1,100 (IQR, 650–1750) mcg, p &lt; 0.001. Median intraoperative total infusion was lower in the ERAS group, 2000 (IQR, 1000–3,750) mL compared to control group, 3,500 (IQR, 2000–5,500) mL, p &lt; 0.001. However, intraoperative norepinephrine infusion was more administered in the ERAS group (52.2% vs. 7.7%, p &lt; 0.001). On postoperative day 1, median cumulative fluid balance was 2,215 (IQR, −150-5880) mL in the ERAS group vs. 4692.5 (IQR, 1770–10,060) mL in the control group, p = 0.002. After the implementation of the ERAS protocol, major morbidity was less frequent in the ERAS group than in the control group (18.8% vs. 75%, p &lt; 0.001). There was no statistical significant difference in 30-day and 90-day mortality (p = 0.07 and p = 0.119, respectively). The probability of postoperative major morbidity and interstitial pulmonary edema were higher in control group (OR 5.637; CI95%:1.178–10.98; p = 0.030 and OR 5.955; CI95% 1.702–9.084; p &lt; 0.001, respectively).

Conclusion

A major morbidity and interstitial pulmonary edema after esophagectomy were decreased after the implementation of the ERAS protocol, without impact on overall mortality.

Evaluation of GSK2789917-induced TRPV4 inhibition in animal models of fluid induced lung injury

Administration of bolus intravenous fluids, common in pre-hospital and hospitalised patients, is associated with increased lung vascular permeability and mortality outside underlying disease states. In our laboratory, the induction of lung injury and oedema through rapid administration of intravenous fluid in rats was reduced by a non-specific antagonist of transient receptor potential vanilloid 4 (TRPV4) channels. The aims of this study were to determine the effect of selective TRPV4 inhibition on fluid-induced lung injury (FILI) and compare the potency of FILI inhibition to that of an established model of TRPV4 agonist-induced lung oedema. In a series of experiments, rats received specific TRPV4 inhibitor (GSK2789917) at high (15 μg/kg), medium (5 μg/kg) or low (2 μg/kg) dose or vehicle prior to induction of lung injury by intravenous infusion of TRPV4 agonist (GSK1016790) or saline. GSK1016790 significantly increased lung wet weight/body weight ratio by 96% and lung wet-to-dry weight ratio by 43% in vehicle pre-treated rats, which was inhibited by GSK2789917 in a dose-dependent manner (IC50 = 3 ng/mL). Similarly, in a single-dose study, bolus saline infusion significantly increased lung wet weight/body weight by 17% and lung wet-to-dry weight ratio by 15%, which was attenuated by high dose GSK2789917. However, in a final GSK2789917 dose-response study, inhibition did not reach significance and an inhibitory potency was not determined due to the lack of a clear dose-response. In the FILI model, TRPV4 may have a role in lung injury induced by rapid-fluid infusion, indicated by inconsistent amelioration with high dose TRPV4 antagonist.

The association of the perioperative fluid balance and cardiopulmonary complications in emergency gastrointestinal surgery: exploration of a randomized trial

BACKGROUND

The association between perioperative fluid administration and risk of complications following emergency surgery is poorly studied. We tested the association between the perioperative fluid balance and postoperative complications following emergency surgery for gastrointestinal obstruction or perforation.

METHODS

We performed a re-assessment of data from the Goal-directed Fluid Therapy in Urgent Gastrointestinal Surgery Trial (GAS-ART) studying intra-operative stroke volume optimization and postoperative zero-balance fluid therapy versus standard fluid therapy. The cohort was divided into three groups at a perioperative fluid balance (FB) of low < 0 L, moderate 0-2 L, or high > 2 L. We used a propensity adjusted logistic regression to analyse the association with cardiopulmonary (primary outcome), renal, infectious, and wound healing complications. Further, the risk of complications was explored on a continuous scale of the FB.

RESULTS

We included 303 patients: 44 patients belonged to the low-FB group, 108 to the moderate-FB group, and 151 to the high-FB group. The median [interquartile range] perioperative FB was -0.9 L [-1.4, -0.6], 0.9 L [0.5, 1.3], and 3.8 L [2.7, 5.3]. The risk of cardiopulmonary complications was significantly higher in the High-FB group 3.4 (1.5-7.6), p = 0.002 (odds ratio (95% confidence interval). On a continuous scale of the fluid balance, the risk of cardiopulmonary complications was minimal at -1 L to 1 L.

CONCLUSION

Following emergency surgery for gastrointestinal obstruction or perforation, a fluid balance < 2.0 L was associated with decreased risk of cardiopulmonary complications without increasing renal complications.

Risk factors for venous thrombosis after esophagectomy

BACKGROUND

Venous thrombosis (VT) after esophagectomy for esophageal cancer is an important complication, potentially leading to pulmonary embolism. However, there are few available information about the risk for the postsurgical VT.

METHODS

This study included 271 patients who underwent esophagectomy for esophageal cancer between 2006 and 2019. Contrast-enhanced computed tomography (CT) was performed for all patients on the seventh postoperative day to survey complications, including VT.

RESULTS

VT was radiologically visualized in 48 patients (17.7%), 8 of whom (16.7%) had pulmonary embolism. The thrombus disappeared in 42 patients, the thrombus size was unchanged in 5 patients, and 1 patient died. Multivariate analysis was performed on factors clinically considered to have a significant influence on thrombus formation. The analysis showed that CVC insertion via the femoral vein (odds ratio, 7.67; 95% CI, 2.64-22.27; P < 0.001), retrosternal reconstruction route (odds ratio, 3.94; 95% CI, 1.90-8.17; P < 0.001) and intraoperative fluid balance < 5 ml/kg/hr (odds ratio, 0.38; 95% CI, 0.17-0.85; P = 0.019) were independently related to VT.

CONCLUSIONS

Intraoperative fluid balance < 5 ml/kg/hr, along with CVC insertion via the femoral vein and retrosternal reconstruction may be potential risk factors for VT after esophagectomy.

Perioperative Patients With Hemodynamic Instability: Consensus Recommendations of the Anesthesia Patient Safety Foundation

In November of 2022, the Anesthesia Patient Safety Foundation held a Consensus Conference on Hemodynamic Instability with invited experts. The objective was to review the science and use expert consensus to produce best practice recommendations to address the issue of perioperative hemodynamic instability. After expert presentations, a modified Delphi process using discussions, voting, and feedback resulted in 17 recommendations regarding advancing the perioperative care of the patient at risk of, or with, hemodynamic instability. There were 17 high-level recommendations. These recommendations related to the following 7 domains: Current Knowledge (5 statements); Preventing Hemodynamic Instability-Related Harm During All Phases of Care (4 statements); Data-Driven Quality Improvement (3 statements); Informing Patients (2 statements); The Importance of Technology (1 statement); Launch a National Campaign (1 statement); and Advancing the Science (1 statement). A summary of the recommendations is presented in Table 1 .

Impact of transesophageal echocardiography dynamic monitoring of left ventricular preload on postoperative gastrointestinal function in colorectal cancer patients undergoing radical surgery

Background

Patients undergoing intestinal tumour surgery are fasted preoperatively for a series of bowel preparations, which makes it difficult to assess the patients' volume, posing a challenge to intraoperative fluid replacement. Besides, inappropriate fluid therapy can cause organ damage and affect the prognosis of patients, and it increases the burden of patients and has a certain impact on patients and families.

Material and methods

The authors designed a single-centre, prospective, single-blinded, randomized, parallel-controlled trial. Fifty-four patients undergoing elective radical resection of colorectal cancer were selected and divided into two groups according to whether transesophageal echocardiography (TEE) was used or not during the operation, that is the goal-directed fluid therapy (GDFT) group (group T) guided by TEE and the restrictive fluid therapy group (group C). Fluid replacement was guided according to left ventricular end-diastolic volume index (LVEDVI) in group T and according to restrictive fluid replacement regimen in group C.

Results

The first postoperative exhaust time and defecation time in group T [(45±21), (53±24) h] were significantly shorter (P<0.05) than those in group C [(63±26), (77±30) h]. There were no significant differences (P>0.05) in liquid intake time and postoperative nausea and vomiting incidences between the two groups. The total intraoperative fluid volume in group T was significantly higher (P<0.05) than that in group C. There was no significant difference (P>0.05) in urine volume between the two groups. There were no significant differences (P>0.05) in lactate content, mean arterial pressure, and heart rate at various time points between the two groups. The length of hospital stay in group C [(18±4) days] was significantly longer (P<0.05) than that in group T [(15±4) days].

Conclusions

For patients undergoing colorectal cancer surgery, fluid therapy by monitoring LVEDVI resulted in faster recovery of gastrointestinal function and shorter hospital stay.

Exploring the need for reconsideration of trial design in perioperative outcomes research: a narrative review

"Enhanced recovery after surgery" is a multimodal effort to control perioperative pathophysiology and improve outcome. However, despite advances in perioperative care, postoperative complications and the need for hospitalisation and prolonged recovery continue to be challenging. This is further complicated by procedure-specific and patient-associated risk factors, given the increase in the number of elderly and frail patients with multiple comorbidities undergoing surgery. This paper is a critical assessment of current methodology for trials in perioperative medicine. We make a plea to reconsider the design of future interventional trials to improve surgical outcome, based upon studies of potentially effective interventions, but often without improvements in recovery. The complexity of perioperative pathophysiology necessitates a procedure- and patient-specific approach whenever outcome is assessed or interventions are planned. With improved understanding of perioperative pathophysiology, the way to improve outcomes looks promising, provided that knowledge and established enhanced recovery programmes are integrated in trial design.

Funding

None.

Comparison between the effects of epidural and intravenous patient-controlled analgesia on postoperative disability-free survival in patients undergoing thoracic and abdominal surgery: A post hoc analysis

BACKGROUND

Thoracic epidural analgesia (TEA) and intravenous patient-controlled analgesia (IV-PCA) are widely used to mitigate immediate postoperative pain; however, their effects on long-term disability-free survival are poorly documented. This study aimed to compare the effects of postoperative TEA and IV-PCA on disability-free survival in patients who underwent thoracic or abdominal surgery.

METHODS

This post hoc analysis of a prospective observational study included 845 inpatients aged ≥55 years that underwent elective thoracic and abdominal surgery between 1 April 2016 and 28 December 2018 in a tertiary care hospital. Inverse probability of treatment weighted (IPTW) using stabilized inverse propensity scores was adopted to minimize bias. The primary outcome in this study was disability-free survival, defined as survival with a 12-item World Health Organization Disability Assessment Schedule 2.0 score of <16%, assessed at 3 months and 1 year after surgery.

RESULTS

The final analysis included 601 patients who received TEA and 244 who received IV-PCA. After IPTW, the weighted incidence of disability-free survival at 3 months and 1 year was 60.5% and 61.4% in the TEA group and 78.3% and 66.2% in the IV-PCA group, respectively. The adjusted OR for disability-free survival at 3 months and 1 year was 0.84 (95% confidence interval [CI]: 0.50-1.39) and 1.21 (95% CI: 0.72-2.05), respectively, for the TEA group.

CONCLUSION

No significant differences were observed in the disability-free survival at 3 months and 1 year after elective thoracic and abdominal surgery in patients aged ≥55 years who received TEA or IV-PCA.

SIGNIFICANCE STATEMENT

This study is the first in our setting to document the long-term effects of patient-controlled analgesia. In a post hoc analysis of our prospective cohort study, we show that although differences in chronic postsurgical pain exist at 3 months post-surgery, disability-free survival rates at 1 year do not differ irrespective of the choice of patient-controlled analgesia. The findings of this study highlight the need for shared decision-making between clinicians and patients.

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.

Prognostic Biomarkers and AKI: Potential to Enhance the Identification of Post-Operative Patients at Risk of Loss of Renal Function

Acute kidney injury (AKI) is a common complication after surgery and the more complex the surgery, the greater the risk. During surgery, patients are exposed to a combination of factors all of which are associated with the development of AKI. These include hypotension and hypovolaemia, sepsis, systemic inflammation, the use of nephrotoxic agents, tissue injury, the infusion of blood or blood products, ischaemia, oxidative stress and reperfusion injury. Given the risks of AKI, it would seem logical to conclude that early identification of patients at risk of AKI would translate into benefit. The conventional markers of AKI, namely serum creatinine and urine output are the mainstay of defining chronic kidney disease but are less suited to the acute phase. Such concerns are compounded in surgical patients given they often have significantly reduced mobility, suboptimal levels of nutrition and reduced muscle bulk. Many patients may also have misleadingly low serum creatinine and high urine output due to aggressive fluid resuscitation, particularly in intensive care units. Over the last two decades, considerable information has accrued with regard to the performance of what was termed "novel" biomarkers of AKI, and here, we discuss the most examined molecules and performance in surgical settings. We also discuss the application of biomarkers to guide patients' postoperative care.