Non-pulmonary infections but not specific pathogens are associated with increased risk of AKI in septic shock

Association of Causative Pathogens With Acute Kidney Injury in Adult Patients With Community-Onset Sepsis

IMPORTANCE

The influence of disease-causing pathogen on acute kidney injury (AKI) in septic patients is poorly understood.

OBJECTIVES

We examined the association of microbial pathogen with AKI among patients with community-onset sepsis.

DESIGN, SETTING, AND PARTICIPANTS

This was a retrospective cohort study. Patient data were acquired from the nationwide multicenter PINC AI Healthcare Database (2016-2020). Participants included adult patients with Centers for Disease Control and Prevention-defined community-onset sepsis.

MAIN OUTCOMES AND MEASURES

The primary exposure was pathogen type identified by culture growth. Microbial cultures from any site were included. The primary endpoint was development of AKI within 7 days of admission using the Kidney Disease: Improving Global Outcomes serum creatinine criteria. We used multilevel logistic regression to examine the association between pathogen type and AKI. Escherichia coli-positive cultures were used as the reference category.

RESULTS

We included 119,733 patients with community-onset sepsis. The median age was 67 years, 33.3% were mechanically ventilated, 36.1% received vasopressors, and hospital mortality was 13.1%. Forty-two thousand twenty-seven patients (35.1%) developed stage 1 AKI, 22,979 (19.2%) developed stage 2 AKI, and 25,073 (20.9%) developed stage 3 AKI. Relative to patients with E. coli infection (odds ratio [OR], 1.0), Proteus species (OR, 1.26; 95% CI, 1.06-1.50), and Streptococcus species (OR, 1.24; 95% CI, 1.10-1.41) were associated with increased odds of AKI. Meanwhile, Pseudomonas aeruginosa (OR, 0.56; 95% CI, 0.49-0.64) and Serratia species (OR, 0.70; 95% CI, 0.52-0.94) were associated with decreased odds of AKI.

CONCLUSIONS AND RELEVANCE

The causative pathogen in patients with sepsis may influence the development of AKI. Further mechanistic and clinical research is needed to confirm these findings and to explore how different pathogens may affect AKI risk in critically ill patients.

Effect of Respiratory Failure on Peripheral and Organ Perfusion Markers in Severe COVID-19: A Prospective Cohort Study

Microvascular dysfunction and inflammation caused by COVID-19 disrupt organ function. The study aimed to investigate the association between the severity of SARS-CoV-2 pneumonia and peripheral and organ perfusion as a consequence of altered microcirculation. A total of 116 patients hospitalized due to severe COVID-19 were enrolled in the study. On admission, the patients underwent a Capillary Refill Time (CRT) examination, finger oxygen saturation measurement, thermal imaging of the hand (FIT), and a kidney Doppler ultrasound. Medical data were collected from the medical history. From the evaluated perfusion parameters, only renal cortex perfusion (RCP) was substantially correlated with the CT score (p < 0.010). The peripheral perfusion parameters of Sat., FIT, CRT, and RCP correlated with the ARDS stages (p = 0.0021; p = 0.038; p < 0.0006; p < 0.0002, respectively). The Oxygenation Ratio value (p < 0.001) was significantly associated with all the perfusion parameters (saturation, CRT, FIT, and RCP) in the multivariable regression analysis model. According to the stepwise retrograde regression analysis, RCP was an independent parameter linked with the Oxygenation Ratio (p < 0.001). Severe COVID-19 can result in microvascular dysfunction influencing peripheral and organ perfusion, which can be measured with various methods. The staging of COVID-19 assessed by CT and the Oxygenation Ratio correlates with RCP, CRT, FIT, and oxygen saturation.

Factors associated with occurrence and severity of acute kidney injury in patients with Sepsis - A retrospective database study

PURPOSE

Sepsis remains the most common cause of acute kidney injury (AKI) and is associated with a high mortality. This study aims to identify laboratory, clinical and demographic factors that are associated with the different stages of AKI in sepsis.

METHODS

We studied patients >18 years who met Sepsis-3 criteria between July 10, 2009 and September 7, 2019 using ordinal logistic regression to determine the factors associated with different stages of AKI. Sensitivity analyses for development of any stage vs no AKI and, separately, the factors associated with receipt of kidney replacement therapy were also done.

RESULTS

Of 31,228 patients meeting Sepsis-3 criteria, 4684 (15%) developed AKI. Of the AKI patients, 53% were KDIGO stage 1, 9% stage 2, and 37% stage 3, with 27% of AKI patients receiving kidney replacement therapy (Stage 3b). Several comorbidities, mechanical ventilation, and pre-sepsis creatinine levels were associated with AKI occurrence and severity. Positive blood culture was associated with a higher risk (OR 1.10 [1.06, 1.15], p < 0.001), while positive respiratory, urine, and wound cultures were associated with lower risks of developing AKI and with lower severity.

CONCLUSION

Presepsis creatinine levels, mechanical ventilation, comorbidities, and positive blood cultures were associated with AKI.

New imaging techniques in AKI

PURPOSE OF REVIEW

Acute kidney injury (AKI) is a common complication in critically ill patients. Understanding the pathophysiology of AKI is essential to guide patient management. Imaging techniques that inform the pathogenesis of AKI in critically ill patients are urgently needed, in both research and ultimately clinical settings. Renal contrast-enhanced ultrasonography (CEUS) and multiparametric MRI appear to be the most promising imaging techniques for exploring the pathophysiological mechanisms involved in AKI.

RECENT FINDINGS

CEUS and MRI can be used to noninvasively and safely evaluate renal macrocirculation and microcirculation and oxygenation in critical ill patients. These techniques show that a decrease in renal blood flow, particularly cortical blood flow, may be observed in septic AKI and may contribute to its development. MRI may be a valuable method to quantify long-term renal damage after AKI that cannot currently be detected using standard clinical approaches.

SUMMARY

CEUS and multiparametric renal MRI are promising imaging techniques but more evidence is needed to show how they can first be more widely used in a research setting to test key hypotheses about the pathophysiology and recovery of AKI, and then ultimately be adopted in clinical practice to guide patient management.

Rates, predictors, and mortality of sepsis-associated acute kidney injury: a systematic review and meta-analysis

BACKGROUND

Due to the high incidence and mortality of sepsis-associated acute kidney injury, a significant number of studies have explored the causes of sepsis-associated acute kidney injury (AKI). However, the opinions on relevant predictive risk factors remain inconclusive. This study aimed to provide a systematic review and meta-analysis to determine the predisposing factors for sepsis-associated AKI.

METHOD

A systematic literature search was performed in the Medline, Embase, Cochrane Library, PubMed, and Web of Science, databases, with an end-date of 25th May 2019. Valid data were retrieved in compliance with specific inclusion and exclusion criteria.

RESULT

Forty-seven observational studies were included for analysis, achieving a cumulative patient number of 55,911. The highest incidence of AKI was caused by septic shock. Thirty-one potential risk factors were included in the meta-analysis. Analysis showed that 20 factors were statistically significant. The odds ratio (OR) and 95% confidence interval (CI), as well as the prevalence of the most frequently-seen predisposing factors for sepsis-associated AKI, were as follows: septic shock [2.88 (2.36-3.52), 60.47%], hypertension [1.43 (1.20-1.70), 38.39%], diabetes mellitus [1.59 (1.47-1.71), 27.57%], abdominal infection [1.44 (1.32-1.58), 30.87%], the administration of vasopressors [2.95 (1.67-5.22), 64.61%], the administration of vasoactive drugs [3.85 (1.89-7.87), 63.22%], mechanical ventilation [1.64 (1.24-2.16), 68.00%], positive results from blood culture [1.60 (1.35-1.89), 41.19%], and a history of smoking [1.60 (1.09-2.36), 43.09%]. Other risk factors included cardiovascular diseases, coronary artery diseases, liver diseases, unknown infections, the administration of diuretics and ACEI/ARB, the infection caused by gram-negative bacteria, and organ transplantation.

CONCLUSION

Risk factors of S-AKI arise from a wide range of sources, making it difficult to predict and prevent this condition. Comorbidities, and certain drugs, are the main risk factors for S-AKI. Our review can provide guidance on the application of interventions to reduce the risks associated with sepsis-associated acute kidney injury and can also be used to tailor patient-specific treatment plans and management strategies in clinical practice.

A pulmonary source of infection in patients with sepsis-associated acute kidney injury leads to a worse outcome and poor recovery of kidney function

BACKGROUND

Hospital mortality rates are higher among patients with sepsis-associated acute kidney injury (SA-AKI) than among patients with sepsis. However, the pathogenesis underlying SA-AKI remains unclear. We hypothesized that the source of infection affects development of SA-AKI. We aim to explore the relationship between the anatomical source of infection and outcome in patients with SA-AKI.

METHODS

Between January 2013 and January 2018, 113 patients with SA-AKI admitted to our Emergency Center were identified and divided into two groups: those with pulmonary infections and those with other sources of infection. For each patient, we collected data from admission until either discharge or death. We also recorded the clinical outcome after 90 days for the discharged patients.

RESULTS

The most common source of infection was the lung (52/113 cases, 46%), followed by gastrointestinal (GI) (25/113 cases, 22.1%) and urinary (22/113, 19.5%) sources. Our analysis showed that patients with SA-AKI had a significantly worse outcome (30/52 cases, P<0.001) and poorer kidney recovery (P=0.015) with pulmonary sources of infection than those infected by another source. Data also showed that patients not infected by a pulmonary source more likely experienced shock (28/61 cases, P=0.037).

CONCLUSION

This study demonstrated that the source of infection influenced the outcome of SA-AKI patients in an independent manner. Lung injury may influence renal function in an as-yet undetermined manner as the recovery of kidney function was poorer in SA-AKI patients with a pulmonary source of infection.

Acute kidney injury is associated with a decrease in cortical renal perfusion during septic shock

Background

Renal perfusion status remains poorly studied at the bedside during septic shock. We sought to measure cortical renal perfusion in patients with septic shock during their first 3 days of care using renal contrast enhanced ultrasound (CEUS).

Methods

We prospectively included 20 ICU patients with septic shock and 10 control patients (CL) without septic shock admitted to a surgical ICU. Cortical renal perfusion was evaluated with CEUS during continuous infusion of Sonovue (Milan, Italy) within the first 24 h (day 0), between 24 and 48 h (day 1) and after 72 h (day 3) of care. Each measurement consisted of three destruction replenishment sequences that were recorded for delayed analysis with dedicated software (Vuebox). Renal perfusion was quantified by measuring the mean transit time (mTT) and the perfusion index (PI), which is the ratio of renal blood volume (rBV) to mTT.

Results

Cortical renal perfusion was decreased in septic shock as attested by a lower PI and a higher mTT in patients with septic shock than in patients of the CL group (p = 0.005 and p = 0.03). PI values had wider range in patients with septic shock (median (min-max) of 74 arbitrary units (a.u.) (3–736)) than in patients of the CL group 228 a.u. (67–440)). Renal perfusion improved over the first 3 days with a PI at day 3 higher than the PI at day 0 (74 (22–120) versus 160 (88–245) p = 0.02). mTT was significantly higher in patients with severe acute kidney injury (AKI) (n = 13) compared with patients with no AKI (n = 7) over time (p = 0.005). The PI was not different between patients with septic shock with severe AKI and those with no AKI (p = 0.29).

Conclusions

Although hemodynamic macrovascular parameters were restored, the cortical renal perfusion can be decreased, normal or even increased during septic shock. We observed an average decrease in cortical renal perfusion during septic shock compared to patients without septic shock. The decrease in cortical renal perfusion was associated with severe AKI occurrence. The use of renal CEUS to guide renal perfusion resuscitation needs further investigation.

Clinical approach to the patient with AKI and sepsis

Sepsis and acute kidney injury (AKI) frequently are combined in critical care patients. They both are associated independently with increased mortality and morbidity. AKI may precede, coincide with, or follow a sepsis diagnosis. Risk factors for sepsis followed by AKI differ from those associated with AKI preceding or coinciding with sepsis, and the pathophysiologic mechanisms may be different. In this article, we review the available clinical, laboratory, and imaging tools available for the recognition of septic AKI. Early identification of high-risk patients and targeted preventive and therapeutic measures are key to reducing the mortality and morbidity of the complex syndrome of septic AKI.