The effect of intra-operative hypotension on acute kidney injury, postoperative mortality and length of stay following emergency hip fracture surgery

Mortality following noncardiac surgery assessed by the Saint Louis University Score (SLUScore) for hypotension: a retrospective observational cohort study

BACKGROUND

The Saint Louis University Score (SLUScore) was developed to quantify intraoperative blood pressure trajectories and their associated risk for adverse outcomes. This study examines the prevalence and severity of intraoperative hypotension described by the SLUScore and its relationship with 30-day mortality in surgical subtypes.

METHODS

This retrospective analysis of perioperative data included surgical cases performed between January 1, 2010, and December 31, 2020. The SLUScore is calculated from cumulative time-periods for which the mean arterial pressure is below a range of hypotensive thresholds. After calculating the SLUScore for each surgical procedure, we quantified the prevalence and severity of intraoperative hypotension for each surgical procedure and the association between intraoperative hypotension and 30-day mortality. We used binary logistic regression to quantify the potential contribution of intraoperative hypotension to mortality.

RESULTS

We analysed 490 982 cases (57.7% female; mean age 57 yr); 33.2% of cases had a SLUScore>0, a median SLUScore of 13 (inter-quartile range [IQR] 7-21), with 1.19% average mortality. The SLUScore was associated with mortality in 12/14 surgical groups. The increases in the odds ratio for death within 30 days of surgery per SLUScore increment were: all surgery types 3.5% (95% confidence interval [95% CI] 3.2-3.9); abdominal/transplant surgery 6% (95% CI 1.5-10.7); thoracic surgery1.5% (95% CI 1-3.3); vascular surgery 3.01% (95% CI 1.9-4.05); spine/neurosurgery 1.1% (95% CI 0.1-2.1); orthopaedic surgery 1.4% (95% CI 0.7-2.2); gynaecological surgery 6.3% (95% CI 2.5-10.1); genitourinary surgery 4.84% (95% CI 3.5-6.15); gastrointestinal surgery 5.2% (95% CI 3.9-6.4); gastroendoscopy 5.5% (95% CI 4.4-6.7); general surgery 6.3% (95% CI 5.5-7.1); ear, nose, and throat surgery 1.6% (95% CI 0-3.27); and cardiac electrophysiology (including pacemaker procedures) 6.6% (95% CI 1.1-12.4).

CONCLUSIONS

The SLUScore was independently, but variably, associated with 30-day mortality after noncardiac surgery.

Urinary oxygen tension and its role in predicting acute kidney injury: A narrative review

Acute kidney injury occurs frequently in the perioperative setting. The renal medulla often endures hypoxia or hypoperfusion and is susceptible to the imbalance between oxygen supply and demand due to the nature of renal blood flow distribution and metabolic rate in the kidney. The current available evidence demonstrated that the urine oxygen pressure is proportional to the variations of renal medullary tissue oxygen pressure. Thus, urine oxygenation can be a candidate for reflecting the change of oxygen in the renal medulla. In this review, we discuss the basic physiology of acute kidney injury, as well as techniques for monitoring urine oxygen tension, confounding factors affecting the reliable measurement of urine oxygen tension, and its clinical use, highlighting its potential role in early detection and prevention of acute kidney injury.

Incidence and predictors of postoperative acute kidney injury in older adults with hip fractures

OBJECTIVES

Main Purpose: To clarify the incidence and predictors of acute kidney injury (AKI) after hip fracture surgery; Secondary Purpose: To investigate the impact of AKI on the length of stay (LOS) and mortality of patients.

METHODS

We retrospectively evaluated data from 644 hip fracture patients at Peking University First Hospital from 2015 to 2021, and divided the patients into AKI and Non-AKI groups according to whether AKI occurred after surgery. Logistic regression was used to clarify the risk factors for AKI, draw ROC curves, and analyze the odds ratio (OR) for LOS and death at 30 days, 3 months, and 1 year for patients with AKI.

RESULTS

The prevalence of AKI after hip fracture was 12.1%. Age, BMI, and postoperative brain natriuretic peptide (BNP) levels were risk factors for AKI after hip fracture surgery. The risk of AKI in underweight patients, overweight patients and obese patients was 2.24, 1.89, and 2.58 times. Compared to patients with BNP levels <800 pg/ml, the risk of AKI was 22.34-fold for postoperative BNP levels>1500 pg/ml. The risk of a one-grade increase in LOS was 2.84 times higher in the AKI group and the mortality of patients with AKI were higher.

CONCLUSION

The incidence of AKI after hip fracture surgery was 12.1%. Advanced age, low BMI, and postoperative high level BNP were risk factors for AKI. Surgeons need to pay more attention to patients with older age, low BMI and high postoperative BNP levels in order to proactively prevent the development of postoperative AKI.

Association of intraoperative hypotension and severe postoperative complications during non-cardiac surgery in adult patients: A systematic review and meta-analysis

Background

Intraoperative hypotension (IOH) is a common side effect of non-cardiac surgery that might induce poor postoperative outcomes. The relationship between the IOH and severe postoperative complications is still unclear. Thus, we summarized the existing literature to evaluate whether IOH contributes to developing severe postoperative complications during non-cardiac surgery.

Methods

We conducted a comprehensive search of PubMed, Embase, Cochrane Library, Web of Science, and the CBM from inception to 15 September 2022. The primary outcomes were 30-day mortality, acute kidney injury (AKI), major adverse cardiac events (myocardial injury or myocardial infarction), postoperative cognitive dysfunction (POCD), and postoperative delirium (POD). Secondary outcomes included surgical-site infection (SSI), stroke, and 1-year mortality.

Results

72 studies (3 randomized; 69 non-randomized) were included in this study. Low-quality evidence showed IOH resulted in an increased risk of 30-day mortality (OR, 1.85; 95% CI, 1.30-2.64; P < .001), AKI (OR, 2.69; 95% CI, 2.15-3.37; P < .001), and stroke (OR, 1.33; 95% CI, 1.21-1.46; P < .001) after non-cardiac surgery than non-IOH. Very low-quality evidence showed IOH was associated with a higher risk of myocardial injury (OR, 2.00; 95% CI, 1.17-3.43; P = .01), myocardial infarction (OR, 2.11; 95% CI, 1.41-3.16; P < .001), and POD (OR, 2.27; 95% CI, 1.53-3.38; P < .001). Very low-quality evidence showed IOH have a similar incidence of POCD (OR, 2.82; 95% CI, 0.83-9.50; P = .10) and 1-year-mortality (OR, 1.66; 95% CI, 0.65-4.20; P = .29) compared with non-IOH in non-cardiac surgery.

Conclusion

Our results suggest IOH was associated with an increased risk of severe postoperative complications after non-cardiac surgery than non-IOH. IOH is a potentially avoidable hazard that should be closely monitored during non-cardiac surgery.

Construction and Validation of a Nomogram for Predicting Acute Kidney Injury After Hip Fracture Surgery

Background

Acute kidney injury (AKI), characterized by sudden impairment of kidney function, is an uncommon complication following hip fracture surgery that is associated with increased morbidity and mortality. We constructed a nomogram to stratify patients according to risk of AKI after hip fracture surgery to guide clinicians in the implementation of timely interventions.

Methods

Patients who received hip fracture surgery from January 2015 to December 2021 were retrospectively identified and divided into a training set (n=448, surgery from January 2015 to December 2019) and a validation set (n=200, surgery from January 2020 to December 2021). Univariate and multivariate logistic regression were used to identify risk factors for AKI after surgery in the training set. A nomogram was constructed based the risk factors for AKI, and was evaluated by receiver operating characteristic (ROC) analysis, calibration curves, and decision curve analysis (DCA).

Results

The mean age was 82.0±6.22 years-old and the prevalence of post-surgical AKI was 13.3%. Age, American Society of Anesthesiologists (ASA) score, the preexistence of chronic kidney disease (CKD), cemented surgery and the decrease of hemoglobin on the first day after surgery were identified as independent risk factors of AKI after hip fracture surgery, and a predictive nomogram was established based on the multivariable model. The predictive nomogram had good discrimination ability (training set: AUC: 0.784, 95% CI: 0.720-0.848; validation set: AUC: 0.804, 95% CI: 0.704-0.903), and showed good validation ability and clinical usefulness based on a calibration plot and decision curve analysis.

Conclusion

A nomogram that incorporated five risk factors including age, ASA score, preexisting CKD, cemented surgery and the decrease of hemoglobin on the first day after surgery had good predictive performance and discrimination. Use of our results for early stratification and intervention has the potential to improve the outcomes of patients receiving hip fracture surgery. Future large, multicenter cohorts are needed to verify the model's performance.

The potential link between obstructive sleep apnea and postoperative neurocognitive disorders: current knowledge and possible mechanisms

PURPOSE

This narrative review examines the current evidence on whether obstructive sleep apnea (OSA) is associated with postoperative delirium (POD) and postoperative cognitive dysfunction (POCD). The mechanisms that could predispose OSA patients to these disorders are also explored.

SOURCE

Relevant literature was identified by searching for pertinent terms in Medline®, Pubmed, ScopusTM, and Google scholar databases. Case reports, abstracts, review articles, original research articles, and meta-analyses were reviewed. The bibliographies of retrieved sources were also searched to identify relevant papers.

PRINCIPAL FINDINGS

Seven studies have investigated the association between OSA and POD, with mixed results. No studies have examined the potential link between OSA and POCD. If these relationships exist, they could be mediated by several mechanisms, including increased neuroinflammation, blood-brain barrier breakdown, cerebrovascular disease, Alzheimer's disease neuropathology, disrupted cerebral autoregulation, sleep disruption, sympathovagal imbalance, and/or disrupted brain bioenergetics.

CONCLUSION

There is very limited evidence that OSA plays a role in postoperative neurocognitive disorders because few studies have been conducted in the perioperative setting. Additional perioperative prospective observational cohort studies and randomized controlled trials of sleep apnea treatment are needed. These investigations should also assess potential underlying mechanisms that could predispose patients with OSA to postoperative neurocognitive disorders. This review highlights the need for more research to improve postoperative neurocognitive outcomes for patients with OSA.

Microvascular Changes of the Non-surgical Eye after General Anesthesia in Optical Coherence Tomography Angiography

Purpose: To investigate chorioretinal vascular changes in the non-surgical eyes of patients who underwent vitreoretinal surgery under general anesthesia using optical coherence tomography angiography (OCTA).Methods: Data from 40 patients who underwent retinal surgery were retrospectively analyzed. Ophthalmologic examinations (including OCTA) were performed in the morning before and after surgery. The presence of intraoperative hypotension (IOH; mean arterial pressure <70 mmHg) was determined based on medical records. The vessel density of superficial and deep retinal capillary plexus layers, choriocapillaris void features, and thickness of the choroid and retina were quantified after image processing. Associations between retinal OCTA parameters and anesthesia profiles were also assessed.Results: DCP vessel density was increased after general anesthesia (p < 0.05). Among the patients who experienced IOH, there was no statistical difference in chorioretinal vessel parameters before and after general anesthesia. Also, we did not observe a difference in chorioretinal vessel parameters after general anesthesia between healthy patients and patients with chronic disease, including hypertension and diabetes (p > 0.05). The duration of anesthesia and average size of the choriocapillaris void (p < 0.05, r = -0.32), and the intraoperative mean arterial pressure (MAP) fluctuation and DCP, showed statistically significant negative linear correlations (p < 0.05, r = -0.38). The choriocapillaris void size and intraoperative MAP fluctuation also displayed a significant negative correlation (p < 0.05, r = -0.37), while the average size signal void showed a weak positive linear correlation (p < 0.01, r = 0.41; and p < 0.01, r = 0.44, respectively).Conclusions: This is the first study to assess the effects of general anesthesia on chorioretinal vessels using OCTA. The Vessel density of the DCP was significantly increased in the non-surgical eye after total vitrectomy under general anesthesia. Furthermore, we found a correlation between MAP fluctuation and choriocapillaris void features. More studies are needed to confirm and expand on these observations.