Precursors to oliguria during major burn resuscitation: An analysis of a prospective observational trial at 5 major US burn centers.

Currently, urine output is the leading variable used to tailor fluid resuscitation in patients with large TBSA burns. However, this metric often lags with respect to resuscitation. Our group sought to identify derangements in variables that precede development of oliguria (<30 cc/hr) that we hypothesize will aid in more efficient resuscitation. We performed a retrospective analysis of 146 adult patients admitted within 4 h of a large TBSA (>20%) burn. We then divided them into two cohorts: those who developed oliguria within 6 h of admission and those who did not. Patients who experienced early oliguria had a higher incidence of invasive SBP < 90 (p = 0.02) or DBP < 40 (p = 0.009), lower minimum bicarbonate level (p = 0.04), more full thickness burns (p = 0.004), and higher TBSA (p = 0.01). More female patients were found in the oliguric group (p = 0.003). Multivariate analysis was used to develop a model to predict development of oliguria. When evaluated together, minimum DBP, sex, TBSA (or percent full thickness burn), and maximum base deficit constituted the most parsimonious model that significantly predicted oliguria (AUC = 0.92). Interestingly, the model lost significance when DBP was omitted, highlighting the importance of diastolic pressure in the development of oliguria.

Initial lactate levels linked to oliguria in term neonates with perinatal asphyxia.

BACKGROUND: Oliguria is a sign of impaired kidney function and has been shown to be an early predictor of adverse prognoses in patients with acute kidney injury. The relationship between urine output (UOP) and early lactate levels in neonates with perinatal asphyxia (PA) has not been extensively explored. This study aimed to investigate the link between oliguria during the first 24 h of life and early lactate levels in neonates with PA. METHODS: The medical records of 293 term neonates with asphyxia from 9216 hospitalized newborns were retrospectively analyzed, including 127 cases designated as the oliguria group and 166 cases as controls. Peripheral arterial blood gas after PA and UOP within 24 h after birth were analyzed. Logistic regression analyses and receiver operating characteristic curve analysis were conducted. RESULTS: Oliguria occurred in 43.34% of neonates with PA. The median UOP of the oliguria and control groups were 0.65 and 1.46 mL/kg/h, respectively. Elevated lactate levels after PA are an independent risk factor for oliguria in the following 24 h (p = 0.01; OR: 1.19; 95%CI: 1.04-1.35) and show a moderate discriminatory power for oliguria (AUC = 0.62). Using a cut off value of 8.15 mmol/L, the positive and negative predictive values and the specificity were 59.34%, 63.86%, and 78.30%, respectively. CONCLUSION: Neonates with elevated lactate levels after PA face a risk of oliguria in the following 24 h. Based on early elevated lactate levels after resuscitation, especially ≥ 8.15 mmol/L, meticulously monitoring UOP will allow this vulnerable population to receive early, tailored fluid management and medical intervention.

Predictors of oliguria in post-traumatic acute kidney injury.

BACKGROUND: Acute kidney injury is classified by urine output into non-oliguric and oliguric variants. Non-oliguric acute kidney injury has lower morbidity and mortality and accounts for up to 64% of acute kidney injury in hospitalized patients. However, the incidence of non-oliguric acute kidney injury in the trauma population and whether the 2 variants of acute kidney injury share the same risk factors is unknown. We hypothesized that oliguria would be present in the majority of acute kidney injury in severely injured trauma patients and that unique risk factors would predispose patients to the development of oliguria. METHODS: Patients admitted to the trauma intensive care unit and diagnosed with an acute kidney injury between 2016 to 2021 were identified. Cases were categorized based on urine output into oliguric (<400 mL per day) and non-oliguric (>400 mL per day) disease. Risk factors, management, and outcomes were compared. Logistic regression was used to identify risk factors associated with oliguria. RESULTS: A total of 227 patients met inclusion criteria. Non-oliguric acute kidney injury accounted for 74% of all cases and was associated with greater survival (78% vs 35.6%, P < .001). Using logistic regression, female sex, vasopressor use, and a greater net fluid balance at 48 hours were all predictive of oliguria (while controlling for age, race, shock index, massive transfusion, operative intervention, cardiac arrest, and nephrotoxic medication exposure). CONCLUSION: Non-oliguria accounts for the majority of post-traumatic acute kidney injury and is associated with improved survival. Specific risk factors for the development of oliguric acute kidney injury include female sex, vasopressor use, and a higher net fluid balance at 48 hours.

Early detection of oliguric events in critically ill patients in the ICU with a novel continuous urine flow measurement device: results of an initial validation study.

OBJECTIVES: Urine output is used to evaluate fluid status and is an important marker for acute kidney injury (AKI). Our primary aim was to validate a new automatic urine output monitoring device by comparison to the current practice - the standard urometer. METHODS: We conducted a prospective observational study in three ICUs. Urine flow measurements by Serenno Medical Automatic urine output measuring device (Serenno Medical, Yokneam, Israel) were compared to standard urometer readings taken automatically at 5-minutes intervals by a camera, and to hourly urometer readings by the nurses, both over 1 to 7 days. Our primary outcome was the difference between urine flow assessed by the Serenno device and reference camera-derived measurements (Camera). Our secondary outcome was the difference between urine flow assessed by the Serenno device and hourly nursing assessments (Nurse), and detection of oliguria. RESULTS: Thirty-seven patients completed the study, with 1,306 h of recording and a median of 25 measurement hours per patient. Bland and Altman analysis comparing the study device to camera measurements demonstrated good agreement, with a bias of -0.4 ml/h and 95% confidence intervals ranging from - 28 to 27ml/h. Concordance was 92%. The correlation between Camera and hourly nursing assessment of urine output was distinctly worse with a bias of 7.2 ml and limits of agreement extending from - 75 to + 107 ml. Severe oliguria (urine output < 0.3 ml/kg/h) lasting 2 h or more was common and observed in 8 (21%) of patients. Among the severe oliguric events lasting more than 3 consecutive hours, 6 (41%) were not detected or documented by the nursing staff. There were no device-related complications. CONCLUSION: The Serenno Medical Automatic urine output measuring device required minimal supervision, little ICU nursing staff attention, and is sufficiently accurate and precise. In addition to providing continuous assessments of urine output, it was considerably more accurate than hourly nursing assessments.

Association between intraoperative oliguria and postoperative acute kidney injury in non-cardiac surgical patients: a systematic review and meta-analysis.

PURPOSE: This systematic review and meta-analysis aimed to evaluate the association between intraoperative oliguria and the risk of postoperative acute kidney injury (AKI) in patients undergoing non-cardiac surgery. METHODS: The MEDLINE and EMBASE databases were searched up to August 2022 for studies in adult patients undergoing non-cardiac surgery, where the association between intraoperative urine output and the risk of postoperative AKI was assessed. Both randomised and non-randomised studies were eligible for inclusion. Study selection and risk of bias assessment were independently performed by two investigators. The risk of bias was evaluated using the Newcastle-Ottawa scale. We performed meta-analysis of the reported multivariate adjusted odds ratios for the association between intraoperative oliguria (defined as urine output < 0.5 mL/kg/hr) and the risk of postoperative AKI using the inverse-variance method with random effects models. We conducted sensitivity analyses using varying definitions of oliguria as well as by pooling unadjusted odds ratios to establish the robustness of the primary meta-analysis. We also conducted subgroup analyses according to surgery type and definition of AKI to explore potential sources of clinical or methodological heterogeneity. RESULTS: Eleven studies (total 49,252 patients from 11 observational studies including a post hoc analysis of a randomised controlled trial) met the selection criteria. Seven of these studies contributed data from a total 17,148 patients to the primary meta-analysis. Intraoperative oliguria was associated with a significantly elevated risk of postoperative AKI (pooled adjusted odds ratio [OR] 1.74; 95% confidence interval [CI] 1.36-2.23, p < 0.0001, 8 studies). Sensitivity analyses supported the robustness of the primary meta-analysis. There was no evidence of any significant subgroup differences according to surgery type or definition of AKI. CONCLUSIONS: This study demonstrated a significant association between intraoperative oliguria and the risk of postoperative AKI, regardless of the definitions of oliguria or AKI used. Further prospective and multi-centre studies using standardised definitions of intraoperative oliguria are required to define the thresholds of oliguria and establish strategies to minimise the risk of AKI.

Urine Output Monitoring for the Diagnosis of Early-Onset Acute Kidney Injury in Very Preterm Infants.

BACKGROUND AND OBJECTIVES: The current threshold used for oliguria in the definition of neonatal AKI has been empirically defined as 1 ml/kg per hour. Urine output criteria are generally poorly documented, resulting in uncertainty in the most accurate threshold to identify AKI in very preterm infants with known tubular immaturity. DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS: We conducted a bicentric study including 473 very preterm infants (240/7-296/7 weeks of gestation) born between January 2014 and December 2018 with urine output measurements every 3 hours during the first 7 days of life and two serum creatinine measurements during the first 10 days of life. AKI was defined using the neonatal Kidney Disease Improving Global Outcomes (KDIGO) definition. We tested whether higher urine output thresholds (1.5 or 2 ml/kg per hour) in modified AKI definitions may better discriminate neonatal mortality compared with the current definition. RESULTS: Early-onset AKI was developed by 101 of 473 (21%) very preterm infants. AKI was diagnosed on the basis of urine output criteria alone (no rise in creatinine) for 27 of 101 (27%) participants. Early-onset AKI was associated with higher risk of death before discharge (adjusted odds ratio, 3.9; 95% confidence interval, 1.9 to 7.8), and the AKI neonatal KDIGO score showed good discriminative performance for neonatal mortality, with an area under the receiver operating characteristic (ROC) curve of 0.68 (95% confidence interval, 0.61 to 0.75). Modified AKI definitions that included higher urine output thresholds showed significantly improved discriminative performance, with areas under the ROC curve of 0.73 (95% confidence interval, 0.66 to 0.80) for the 1.5-ml/kg per hour threshold and 0.75 (95% confidence interval, 0.68 to 0.81) for the 2-ml/kg per hour threshold. CONCLUSIONS: Early-onset AKI was diagnosed on the basis of urine output exclusively for a quarter of the cases. Furthermore, modified AKI definitions that included higher urine output improved the discriminative performance for predicting mortality.

External validation of a deep-learning model to predict severe acute kidney injury based on urine output changes in critically ill patients.

OBJECTIVES: The purpose of this study was to externally validate algorithms (previously developed and trained in two United States populations) aimed at early detection of severe oliguric AKI (stage 2/3 KDIGO) in intensive care units patients. METHODS: The independent cohort was composed of 10'596 patients from the university hospital ICU of Amsterdam (the "AmsterdamUMC database") admitted to their intensive care units. In this cohort, we analysed the accuracy of algorithms based on logistic regression and deep learning methods. The accuracy of investigated algorithms had previously been tested with electronic intensive care unit (eICU) and MIMIC-III patients. RESULTS: The deep learning model had an area under the ROC curve (AUC) of 0,907 (± 0,007SE) with a sensitivity and specificity of 80% and 89%, respectively, for identifying oliguric AKI episodes. Logistic regression models had an AUC of 0,877 (± 0,005SE) with a sensitivity and specificity of 80% and 81%, respectively. These results were comparable to those obtained in the two US populations upon which the algorithms were previously developed and trained. CONCLUSION: External validation on the European sample confirmed the accuracy of the algorithms, previously investigated in the US population. The models show high accuracy in both the European and the American databases even though the two cohorts differ in a range of demographic and clinical characteristics, further underlining the validity and the generalizability of the two analytical approaches.

Acute Kidney Injury and Renal Failure in Horses.

Nephrotoxic and hemodynamically mediated disorders are the most common causes of acute renal failure (ARF) in horses and foals. Leptospira spp. is the most common infectious cause of ARF. Initial treatments for ARF include elimination of nephrotoxic drugs, correction of predisposing disorders, and fluid therapy to promote diuresis. Horses and foals with polyuric ARF often have a good prognosis, while those with oliguric or anuric ARF have a guarded to poor prognosis. When fluid therapy is unsuccessful in improving urine production, various drugs treatments have been used in an attempt to increase urine production, but none are consistently effective in converting oliguria to polyuria.

The role of Cushing's reflex and the vasopressin-mediated oligoanuric response to intracranial hypertension in patients with abdominal compartment syndrome.

BACKGROUND: We examined the link between increased intra-abdominal pressure, intracranial pressure, and vasopressin release as a potential mechanism. Intra-abdominal pressure, produced by abdominal-cavity insufflation with carbon dioxide (CO2) during laparoscopic abdominal procedures to facilitate visualization, is associated with various complications, including arterial hypertension and oliguria. METHODS: Mean arterial pressure, optic nerve sheath diameter, measured as a proxy for intracranial pressure, plasma vasopressin, serum and urine osmolarity, and urine output were measured 4 times during laparoscopic sleeve gastrectomy in 42 patients: before insufflation with CO2 (T0); after insufflation to 15 cm water (H2O) pressure, with 5 cm H2O positive end-expiratory pressure (T1); after positive end-expiratory pressure was raised to 10 cm H2O (T2); and after a return to the baseline state (T3). Mean values at T0 to T3 and the directional consistency of changes (increase/decrease/ unchanged) were compared among the 4 data-collection points. RESULTS: Statistically significant elevations (all P ≤ .001) were noted from T0 to T1 and from T0 to T2 in mean arterial pressure, optic nerve sheath diameter, and vasopressin, followed by decreases at T3. For optic nerve sheath diameter and vasopressin, the increases at T1 and T2 occurred in 98% and 100% of patients, ultimately exceeding normal levels in 88 and 97%, respectively. Conversely, urine output fell from T0 to T1 and T2 by 60.9 and 73.4%, decreasing in 88.1% of patients (all P < .001). Patients with class II obesity exhibited statistically greater increases in optic nerve sheath diameter and vasopressin, but statistically less impact on urine output, than patients with class III obesity. CONCLUSION: Increased mean arterial pressure, intracranial pressure, and vasopressin release appear to be intermediary steps between increased intra-abdominal pressure and oliguria. Further research is necessary to determine any causative links between these physiological changes.

Association of Oliguria With Acute Kidney Injury Diagnosis, Severity Assessment, and Mortality Among Patients With Critical Illness.

Importance: The current definition and staging of acute kidney injury (AKI) considers alterations in serum creatinine (sCr) level and urinary output (UO). However, the relevance of oliguria-based criteria is disputed. Objective: To determine the contribution of oliguria, as defined by the Kidney Disease: Improving Global Outcomes (KDIGO) criteria, to AKI diagnosis, severity assessment, and short- and long-term outcomes. Design, Setting, and Participants: This cohort study included adult patients admitted to a multidisciplinary intensive care unit from January 1, 2010, to June 15, 2020. Patients receiving long-term dialysis and those who declined consent were excluded. Daily sCr level and hourly UO measurements along with sociodemographic characteristics and severity scores were extracted from electronic medical records. Long-term mortality was assessed by cross-referencing the database with the Swiss national death registry. The onset and severity of AKI according to the KDIGO classification was determined using UO and sCr criteria separately, and their agreement was assessed. Main Outcomes and Measures: Using a multivariable model accounting for baseline characteristics, severity scores, and sCr stages, the association of UO criteria with 90-day mortality was evaluated. Sensitivity analyses were conducted to assess how missing sCr, body weight, and UO values, as well as different sCr baseline definitions and imputations methods, would affect the main results. Results: Among the 15 620 patients included in the study (10 330 men [66.1%] with a median age of 65 [IQR, 53-75] years, a median Simplified Acute Physiology Score II score of 40.0 [IQR, 30.0-53.0], and a median follow-up of 67.0 [IQR, 34.0-100.0] months), 12 143 (77.7%) fulfilled AKI criteria. Serum creatinine and UO criteria had poor agreement on AKI diagnosis and staging (Cohen weighted κ, 0.36; 95% CI, 0.35-0.37; P < .001). Compared with the isolated use of sCr criteria, consideration of UO criteria enabled identification of AKI in 5630 patients (36.0%). Those patients had a higher 90-day mortality than patients without AKI (724 of 5608 [12.9%] vs 288 of 3462 [8.3%]; P < .001). On multivariable analysis accounting for sCr stage, comorbidities, and illness severity, UO stages 2 and 3 were associated with a higher 90-day mortality (odds ratios, 2.4 [95% CI, 1.6-3.8; P < .001] and 6.2 [95% CI, 3.7-10.5; P < .001], respectively). These results remained significant in all sensitivity analyses. Conclusions and Relevance: The findings of this cohort study suggest that oliguria lasting more than 12 hours (KDIGO stage 2 or 3) has major AKI diagnostic implications and is associated with outcomes irrespective of sCr elevations.

Hypocomplementemia (C3) as an independent predictor for children with acute post-streptococcal glomerulonephritis: a long-term observation.

OBJECTIVE: The aim of this study was to examine the altering patterns in clinical characteristics and severity of acute post-streptococcal glomerulonephritis (APSGN) in children. PATIENTS AND METHODS: We analyzed the medical records of 119 children who were diagnosed with APSGN from 1987 to 2018, retrospectively. The patients were divided into two groups: Group I (n=72, before 1998) and Group II (n=47, after 1998). Clinical, radiologic, and laboratory findings were compared between the two groups. RESULTS: The clinical manifestations, including vomiting (20.8% vs. 4.3%, p=0.014), oliguria (40.3% vs. 19.1%, p=0.016), and generalized edema (86.1% vs. 63.8%, p=0.005), were statistically less frequent since 1998. Pulmonary edema on chest X-ray (22.7% vs. 4.4%, p=0.014) was less frequent in Group II than in Group I. The level of BUN (23.3±19.3 vs. 18.8±11.2, p=0.009) was lower in Group II than in Group I, while that of creatinine was not significantly different between the two groups. C3 level was an independent factor for predicting the development of edema (odds ratio [OR]: 1.034, 95% CI: 1.010-1.060, p=0.006) and acute nephritic symptoms (≥2) (OR: 0.974, 95% CI: 0.952-0996, p=0.020). It was also negatively correlated with an increasing number of acute nephritic symptoms, including oliguria and edema, in patients with APSGN (R=-0.182, p=0.048). CONCLUSIONS: This study demonstrated that APSGN had favorable clinical manifestations and severity over the past 30 years. The monitoring of C3 levels can be used to assess the disease severity and risk of complications, including edema and oliguria, which are decreasing in South Korean children.

Automated versus manual urine output monitoring in the intensive care unit.

Acute kidney injury (AKI) is defined by changes in serum creatinine and urine output (UO). Significant limitations exist regarding accurate ascertainment of urine output even within the intensive care unit. We sought to evaluate an automated urine output collections system and compare it to nursing measurements. We prospectively collected urine output using an electronic urine monitoring system and compared it to charted hourly UO in 44 patients after cardiac surgery at a single university hospital ICU. We calculated UO and oliguria rates and compared them to data from the sensor and from nursing charting. A total of 187 hourly UO measurements were obtained and on average, UO was reported 47 min late, with a median of 18 min, and a maximum of almost 6 h. Patients had a mean hourly UO of 76.3 ml over the observation period. Compared to manual measurements by study personnel, nurses significantly overestimated hourly UO by 19.9 ml (95% CI: 10.3; 29.5; p = < 0.001). By contrast, the mean difference between the UO measured with the sensor and by study personnel was 2.29 ml (95% CI: - 6.7; 11.3), p = 0.61. Electronic UO monitoring is significantly more accurate than nurse-performed manual measurements in actual intensive care patients. Furthermore, timely ascertainment of UO is difficult to achieve with manual technique, resulting in important delays in detecting oliguria perhaps leading to missed cases of AKI.

Intraoperative oliguria does not predict postoperative acute kidney injury in major abdominal surgery: a cohort analysis / A oligúria intraoperatória não prediz lesão renal aguda pós-operatória em grandes cirurgias abdominais: Análise de uma coorte

Abstract Background: Acute kidney injury (AKI) is a common complication in patients undergoing major abdominal surgery and is associated with considerable morbidity and mortality. Several studies investigating the association between intraoperative urine output and postoperative AKI have shown conflicting results. Here, we investigated the association of intraoperative oliguria with postoperative AKI in a cohort of patients submitted to elective major abdominal surgery. Methods: This was a single-center retrospective analysis of adult patients who underwent elective major abdominal surgery from January 2016 to December 2018. AKI was defined according to the serum creatinine criteria of the KDIGO classification. Intraoperative oliguria was defined as urine output of less than 0.5 mL/kg/h. Risk factors were evaluated using multivariate logistic regression analysis. Results: A total of 165 patients were analyzed. In the first 48 h after surgery the incidence of AKI was 19.4%. Postoperative AKI was associated with hospital mortality (p=0.011). Twenty percent of patients developed intraoperative oliguria. There was no association between preexisting comorbidities and development of intraoperative oliguria. There was no correlation between the type of anesthesia used and occurrence of intraoperative oliguria, but longer anesthesia time was associated with intraoperative oliguria (p=0.007). Higher baseline SCr (p=0.001), need of vasoactive drugs (p=0.007), and NSAIDs use (p=0.022) were associated with development of intraoperative oliguria. Intraoperative oliguria was not associated with development of postoperative AKI (p=0.772), prolonged hospital stays (p=0.176) or in-hospital mortality (p=0.820). Conclusion: In this cohort of patients we demonstrated that intraoperative oliguria does not predict postoperative AKI in major abdominal surgery.

Resumo Introdução: Lesão renal aguda (LRA) é uma complicação comum em pacientes submetidos a grandes cirurgias abdominais, e está associada a considerável morbimortalidade. Vários estudos investigando a associação entre débito urinário intraoperatório e LRA pós-operatória mostraram resultados conflitantes. Neste trabalho investigamos a associação de oligúria intraoperatória com LRA pós-operatória em uma coorte de pacientes submetidos à grandes cirurgias abdominais. Métodos: Análise retrospectiva de centro único envolvendo pacientes adultos submetidos à grandes cirurgias abdominais, de janeiro de 2016 a dezembro de 2018. A LRA foi definida segundo critérios de creatinina da KDIGO. Definimos oligúria intraoperatória como débito urinário inferior a 0,5 mL/kg/h. Fatores de risco foram avaliados por análise de regressão logística multivariada. Resultados: Analisamos 165 pacientes. Nas primeiras 48 horas após a cirurgia, a incidência de LRA foi de 19,4%. LRA pós-operatória foi associada à mortalidade hospitalar (p = 0,011). 20% dos pacientes desenvolveram oligúria intraoperatória, sem associação com comorbidades preexistentes. Não houve correlação entre o tipo de anestesia e oligúria intraoperatória; entretanto, maior tempo de anestesia esteve associado à oligúria intraoperatória (p = 0,007). Maior creatinina sérica (Cr) inicial (p = 0,001), necessidade de drogas vasoativas (p = 0,007) e uso de AINEs (p = 0,022) foram associados à oligúria intraoperatória. Oligúria intraoperatória não foi associada ao desenvolvimento de LRA no pós-operatório (p = 0,772), à permanência hospitalar prolongada (p = 0,176) ou à mortalidade intra-hospitalar (p = 0,820). Conclusão: Demonstramos que a oligúria intraoperatória não prediz LRA pós-operatória em cirurgias abdominais de grande porte.