AIM OF REVIEW: Acute kidney injury (AKI) after cardiac surgery is a relatively common postoperative complication and is independently related to increased mortality and morbidity. METHOD: In this review, we will focus on risk factors of developing AKI, early detection by biomarkers and preventive strategies for AKI after adult cardiac surgery. RECENT FINDINGS: Many perioperative factors affect renal function and acute AKI following cardiac surgery. Novel biomarkers of kidney injury such as neutrophil gelatinase-associated lipocalin (NGAL), interleukin-18 (IL-18), cystatin C (CysC), have the potential to facilitate the early diagnosis of cardiac surgery associated AKI (CSA-AKI). Pharmacological interventions have been inconsistent to their efficacy, and to date, there is no compelling pharmacologic agent known to reduce the risk of AKI or treat established AKI. SUMMARY: Preventive strategies of AKI focus on optimal perioperative management.

Aim of review

Acute kidney injury (AKI) after cardiac surgery is a relatively common postoperative complication and is independently related to increased mortality and morbidity.

Method

In this review, we will focus on risk factors of developing AKI, early detection by biomarkers and preventive strategies for AKI after adult cardiac surgery.

Recent findings

Many perioperative factors affect renal function and acute AKI following cardiac surgery. Novel biomarkers of kidney injury such as neutrophil gelatinase-associated lipocalin (NGAL), interleukin-18 (IL-18), cystatin C (CysC), have the potential to facilitate the early diagnosis of cardiac surgery associated AKI (CSA-AKI). Pharmacological interventions have been inconsistent to their efficacy, and to date, there is no compelling pharmacologic agent known to reduce the risk of AKI or treat established AKI.

Summary

Preventive strategies of AKI focus on optimal perioperative management.

Background

Many studies have compared propofol-based anesthesia with inhalational anesthesia. Results from several studies have shown improved postoperative analgesia after propofol anesthesia, but other studies showed contradictory results. There are no large prospective studies that compare postoperative pain after propofol versus inhalational anesthesia. This meta-analysis was designed to focus on this question.

Methods

A systematic literature search for randomized controlled trials that compared propofol-based anesthesia with volatile agents-based anesthesia in adults undergoing surgery was conducted. Published data were pooled for the meta-analysis with Review Manager (ie, RevMan). The main outcomes included postoperative pain intensity, opioid consumption, need for rescue analgesics, and time to first analgesia.

Results

Thirty-nine clinical trials with a combined subject population of 4520 patients came within the purview of this meta-analysis. The investigated volatile agents included isoflurane, sevoflurane, and desflurane. Compared with inhalational anesthetics, the propofol use was associated with a reduced postoperative pain intensity at rest at 30 minutes, 1 hour, and 12 hours (mean difference in pain scores, 30 minutes, -0.48 [visual analog scale, 0-10]; 99% confidence interval [CI], -1.07 to 0.12, P = 0.04) and reduced morphine-equivalent consumption 0 to 24 hours postoperatively (mean difference in morphine-equivalent consumption, -2.68 mg; 99% CI, -6.17 to 0.82; P = 0.05). Fewer patients required postoperative rescue analgesics during 0 to 24 hours after surgery under propofol anesthesia (risk ratio, 0.87; 99% CI, 0.74-1.03; P = 0.04). In addition, patients anesthetized with propofol required administration of postoperative analgesia later than those anesthetized with volatiles (mean difference in time to first analgesic administration, 6.12 minutes; 99% CI, 0.02-12.21; P = 0.01). Considering that Z statistic in RevMan 5.3 does not perform optimally in highly heterogeneous samples among groups or many combinations of groups with small sample sizes, a P value of <.01 was considered statistically significant. On the basis of this threshold, none of the aforementioned results are statistically significant.

Conclusions

The current results are affected by substantial heterogeneity, which makes it difficult to predict significant differences in postoperative pain control between propofol anesthesia and inhalational anesthesia. Further large, randomized controlled trials are needed to corroborate these results and to detect differences (if any) between propofol and inhalational anesthesia on postoperative pain.

Coronary artery bypass graft (CABG) is associated with a high risk of mortality and morbidity; thus, assessment of surgery quality is necessary. In this perspective, we will focus on the structure, process, and outcomes measured as quality assessment. A set of 21 evidence-based structure, process, and outcome measures were selected as National Quality Forum. Of these, the Society of Thoracic Surgeons ultimately chose 11 individual quality measures grouped them into four domains used to assess the quality of CABGs. These four domains consisted of perioperative medical care, operative care, risk-adjusted operative mortality and postoperative risk-adjusted major morbidity. These measures have been useful as quality improvement tools in assessing the quality of CABG surgery.

Background

Acute kidney injury (AKI) is a common complication after surgery and is associated with detrimental outcomes. This systematic review and meta-analysis evaluated perioperative dexmedetomidine on AKI and renal function after non-cardiac surgery.

Methods

PubMed, Embase, and Cochrane Library databases were searched until August 2023 for randomised trials comparing dexmedetomidine with normal saline on AKI and renal function in adults undergoing non-cardiac surgery. The primary outcome was the incidence of AKI (according to Kidney Disease Improving Global Outcomes or Acute Kidney Injury Network criteria). Meta-analysis was performed using a random-effect model. We conducted sensitivity analysis, trial sequential analysis (TSA), and Grading of Recommendations Assessment, Development and Evaluation level of evidence.

Results

Twenty-three trials involving 2440 patients were included. Dexmedetomidine administration, as compared to normal saline, significantly reduced the incidence of AKI (7.4% vs. 13.2%; risk ratio = 0.57, 95% CI = 0.40 to 0.83, P =  0.003, I² = 0%; a high level of evidence); TSA and sensitivity analyses suggested the robustness of this outcome. For the renal function and inflammation parameters, dexmedetomidine decreased serum creatinine, blood urea nitrogen, cystatin C, tumour necrosis factor-α, and interleukin-6, and increased urine output and estimated glomerular filtration rate. Additionally, dexmedetomidine reduced postoperative nausea and vomiting and length of hospital stay. Dexmedetomidine was associated with an increased rate of bradycardia, but not hypotension.

Conclusion

Dexmedetomidine administration reduced the incidence of AKI and improved renal function after non-cardiac surgery. Based on a high level of evidence, dexmedetomidine is recommended as a component of perioperative renoprotection.

Registration

International Prospective Register of Systematic Reviews; Registration number: CRD42022299252.

Pharmacological preconditioning reduces myocardial infarct size in ischaemia-reperfusion (I-R) injury. Dexmedetomidine, a selective α₂ -adrenoceptor agonist, has a proven cardioprotective effect when administered prior to I-R, although the underlying mechanisms for this effect are not fully understood. We evaluated whether dexmedetomidine preconditioning could induce a myocardio-protective effect against I-R injury by inhibiting associated inflammatory processes through downregulation of the high mobility group box 1 (HMGB1)-toll-like receptor 4 (TLR4)-nuclear factor κB (NF-κB) signalling pathway. Seventy rats were randomly assigned to seven groups: a control and six test groups, involving I-R for 30 and 120 minutes, respectively, in isolated rat hearts and different pretreatment protocols with dexmedetomidine (10 nmol/L) as well as yohimbine (1 μmol/L) and recombinant HMGB1 peptide (rHMGB1; 20 μg/L), alone or in combination with dexmedetomidine. Cardiac function was recorded; myocardial HMGB1, TLR4, and NF-κB activities and levels of tumour necrosis factor-α (TNF-α) and interleukin-6 (IL-6) were measured as were lactate dehydrogenase (LDH) and creatine kinase (CK) in coronary outflow. Dexmedetomidine preconditioning significantly improved cardiac function (P<.05), downregulated the expression of HMGB1-TLR4-NF-κB, reduced levels of TNF-α and IL-6 in isolated ventricles during I-R injury, and significantly reduced CK and LDH levels in coronary outflow (P<.05). All of these effects were partially reversed by yohimbine (P<.05) or rHMGB1 (P<.05). Dexmedetomidine preconditioning alleviated myocardial I-R injury in rats through inhibition of inflammatory processes associated with downregulation of the HMGB1-TLR4-NF-κB signalling pathway via activation at α₂ -adrenergic receptors.

Purpose

Patients undergoing major laparoscopic surgery often experience significant pain and postoperative nausea and vomiting (PONV). Deep neuromuscular block (NMB) improves surgical conditions and facilitates the application of low intra-abdominal pressure (IAP), which may be beneficial for these patients. This study is designed to determine the effects of deep NMB combined with low IAP, as compared to moderate NMB combined with standard IAP, on patients' nociceptive recovery after major laparoscopic gastrointestinal surgery.

Study design and methods

This single-center randomized controlled trial will include 220 patients scheduled for major laparoscopic gastrointestinal surgery (lasts for ≥ 90 minutes). Patients will be randomly assigned, with a 1:1 ratio, into a deep NMB + low IAP group (train of four = 0, post-tetanic count = 1-3, IAP = 8 mmHg) and a moderate NMB + standard IAP group (train of four = 1-3, IAP = 12 mmHg). If the surgical workspace is inadequate, the surgeons can request a step increase of 1 mmHg in IAP during 3-min intervals. The upper limit of IAP will be set at 15 mmHg. Postoperative recovery will be assessed using the postoperative quality recovery scale (PQRS). The primary outcome of this trial is the PQRS nociceptive recovery (including pain and PONV) at postoperative day (POD) 1. The secondary outcomes include recovery in other PQRS domains at POD 1, and recovery in all PQRS domains in a post-anesthesia care unit, at POD 3 in the surgical wards, at hospital discharge, and at postoperative 30 days. For the sample size estimation, 110 patients in each group (220 in total) would be needed to detect an absolute increase rate of 20% in the PQRS nociceptive domain in the deep NMB + low IAP group at POD 1.

Discussion

This study investigates the effects of deep NMB combined with low IAP on postoperative PQRS nociceptive recovery in patients undergoing major laparoscopic gastrointestinal surgery. We expect that this deep NMB + low IAP strategy would improve postoperative pain and PONV following major laparoscopic gastrointestinal surgery.

Depressive symptoms are common among perimenopausal women with breast cancer having modified radical mastectomy. Esketamine exerts antidepressant effects. This study aims to assess whether an intraoperative sub-anesthetic dose of esketamine prevents postoperative depressive symptoms in these patients. In this randomized, triple-blinded, placebo-controlled trial, we will enroll 130 perimenopausal women (aged 45-60 years) with breast cancer undergoing unilateral modified radical mastectomy. Patients will be randomly assigned with a 1:1 ratio to receive either esketamine (0.25 mg/kg i.v.) or normal saline after anesthesia induction and before skin incision. The primary outcome is the incidence of depressive symptoms at day 30 postoperatively, assessed using the Beck's Depression Inventory (BDI). Secondary outcomes include incidence of depressive symptoms and BDI scores at day 1, 3, and 180 postoperatively, anxiety symptoms and scores at day 1, 3, 30, and 180 postoperatively, pain intensity and quality of recovery at day 1 and 2 postoperatively, nausea and vomiting within 48 hours postoperatively, length of postoperative hospital stay, and cancer-specific outcomes. Data will be analyzed in the modified intention-to-treat population. This is the first trial to evaluate the effects of a sub-anesthetic dose of esketamine on depressive symptoms in perimenopausal women after modified radical mastectomy. The results of this study will help to improve their mental health and recovery after breast cancer surgery. Chinese Clinical Trial Registry (ChiCTR2200064348).

Purpose

Chronic postsurgical pain (CPSP) is a common complication after thoracic surgery and associated with long-term adverse outcomes. This study aims to develop two prediction models for CPSP after video-assisted thoracic surgery (VATS).

Methods and analysis

This single-center prospective cohort study will include a total of 500 adult patients undergoing VATS lung resection (n = 350 for development and n = 150 for external validation). Patients will be enrolled continuously at The First Affiliated Hospital of Soochow University in Suzhou, China. The cohort for external validation will be recruited in another time period. The outcome is CPSP, which is defined as pain with the numerical rating scale score of 1 or higher 3 months after VATS. Univariate and multivariable logistic regression analyses will be performed to develop two CPSP prediction models based on patients' data of postoperative day 1 and day 14, respectively. For internal validation, we will use the bootstrapping validation technique. For external validation, the discrimination capability of the models will be assessed using the area under the receiver operating characteristic curve, and the calibration will be evaluated using the calibration curve and Hosmer-Lemeshow goodness-of-fit statistic. The results will be presented in model formulas and nomograms.

Conclusion

Based on the development and validation of the prediction models, our results contribute to early prediction and treatment of CPSP after VATS.

Trial registration

Chinese Clinical Trial Register (ChiCTR2200066122).