Renal Tissue Oxygen Saturation Research Articles

The relationship between trajectories of renal oxygen saturation and acute kidney injury: a prospective cohort study with a secondary analysis

BackgroundAcute kidney injury (AKI) is a major postoperative consequence, affecting prognosis of older patients. Effective prediction or intervention to predict or prevent the incidence of AKI is currently unavailable.AimsDynamic changes of renal tissue oxygen saturation (RSO2) during surgery process are understudied and we intended to explore the distinct trajectories and associations with postoperative AKI.MethodsThis was a secondary analysis including data for older patients who underwent open hepatectomy surgery with informed consent. Latent class mixed models (LCMM) method was conducted to generate trajectories of intraoperative renal tissue RSO2 through different time points. The primary outcome was postoperative 7-day AKI. The univariate and multivariate regression analysis were performed to identify the relationship between distinct trajectories of renal tissue RSO2 and the risk of AKI. Meanwhile, the prediction efficacy of renal tissue RSO2 at different time points was compared to find potential intervention timing.ResultsPostoperative AKI occurred in 14 (15.2%) of 92 patients. There are two distinct renal tissue RSO2 trajectories, with 44.6% generating "high-downwards" trajectory and 55.4% generating "consistently-high" trajectory. Patients with "high-downwards" trajectory had significantly higher risk of postoperative AKI than another group (Unadjusted OR [Odds Ratio] = 3.790, 95% CI [Confidence Interval]: 1.091–13.164, p = 0.036; Adjusted OR = 3.973, 95% CI 1.020–15.478, p = 0.047, respectively). Predictive performance was 71.4% sensitivity and 60.3% specificity for "high-downwards" trajectory of renal tissue RSO2 to identify AKI. Furthermore, the renal tissue RSO2 exhibited the lowest level and the best results in terms of the sensitivity during the hepatic occlusion period, may be considered as a "time of concern".ConclusionsOlder patients undergoing hepatectomy may show high-downwards trajectory of renal tissue RSO2, indicating a higher risk of AKI, and the lowest level was identified during the hepatic occlusion period. These findings may help to provide potential candidates for future early recognition of deterioration of kidney function and guide interventions.

Intraoperative renal desaturation and postoperative acute kidney injury in older patients undergoing liver resection: A prospective cohort study

Study objectiveTo determine the association between intraoperative renal tissue desaturation as measured using near-infrared spectroscopy and increased likelihood of developing postoperative acute kidney injury (AKI) in older patients undergoing hepatectomy. DesignA multicenter prospective cohort study. SettingThe study was conducted at two tertiary hospitals in China from September 2020 to October 2021. Patients157 older patients (≥ 60 years) undergoing open hepatectomy surgery. Interventions and measurementsRenal tissue oxygen saturation was continuously monitored during operation using near-infrared spectroscopy. The exposure of interest was intraoperative renal desaturation, defined as at least 20% relative decline in renal tissue oxygen saturation from baseline. The primary outcome was postoperative AKI, defined using the Kidney Disease: Improving Global Outcomes criteria according to the serum creatinine criteria. Main resultsRenal desaturation occurred in 70 of 157 patients. Postoperative AKI was observed in 23% (16/70) and 8% (7/87) of patients with versus without renal desaturation. Patients with renal desaturation were at higher risk of AKI than patients without renal desaturation (adjusted odds ratio 3.41, 95% confidence interval: 1.12–10.36, p = 0.031). Predictive performance was 65.2% sensitivity and 33.6% specificity for hypotension alone, 69.6% sensitivity and 59.7% specificity for renal desaturation alone, and 95.7% sensitivity and 26.9% specificity for combined use of hypotension and renal desaturation. ConclusionsIntraoperative renal desaturation occurred in >40% in our sample of older patients undergoing liver resection and was associated with increased risk of AKI. Intraoperative near-infrared spectroscopy monitoring enhances the detection of AKI.

Cerebral and Renal Oxygenation in Infants Undergoing Laparoscopic Gastrostomy Tube Placement

The aim of this study was to evaluate the effects of a carbon dioxide pneumoperitoneum on cerebral and renal oxygenation and oxygen extraction, in a cohort of infants from the neonatal intensive care unit, undergoing laparoscopic gastrostomy. After institutional review board approval, between February 2018 and June 2019, infants 0-3mo corrected age, undergoing laparoscopic gastrostomy tube placement, were included. Strict exclusion criteria created a homogeneous cohort. Cerebral and renal tissue oxygen saturation (rSO2) by near-infrared spectroscopy, skin surface oxygen saturation (SpO2), by pulse oximetry, and amplitude-integrated electroencephalography were measured. Monitoring was divided into preoperative, intraoperative and postoperative time periods. Cerebral and renal fractional tissue oxygen extraction was calculated using arterial (SpO2) and tissue oxygen saturation (rSO2): (SpO2-rSO2SpO2)X100. Data were averaged into one-minute epochs and significant changes from baseline during the intraoperative and postoperative periods were detected using one-way analysis of variance with repeated measures. This pilot study examined sixteen infants, born at a median gestational age of 34.2wk (range: 23.0-40.6) with a median corrected age of 42.9wk (range: 40.0-46.3) at operation. None had seizure activity or altered sleep-wake cycles. No statistically significant variations in cerebral and renal tissue oxygenation and extraction were observed. Pulse oximetry did demonstrate significant variation from baseline on analysis of variance, but post hoc analysis did not identify any one specific time point at which this difference was significant. During a short infant laparoscopic procedure, no significant alteration in cerebral or renal oxygenation or oxygen extraction was observed. No seizure activity or changes in infant sleep-wake cycles occurred.

Effect of pneumoperitoneum pressure and the depth of neuromuscular block on renal function in patients with diabetes undergoing laparoscopic pelvic surgery: study protocol for a double-blinded 2 \xd7 2 factorial randomized controlled trial

BackgroundPatients with diabetes mellitus are at a high risk of developing postoperative acute kidney injury. For patients receiving laparoscopic surgery, standard-pressure pneumoperitoneum (SPP) currently applied in clinical practice also undermines renal perfusion. Several studies have shown that low-pressure pneumoperitoneum (LPP) might reduce pressure-related ischemic renal injury. However, LPP may compromise the view of the surgical field. Previous studies have indicated that deep neuromuscular blockade (NMB) can ameliorate this issue. However, the conclusion is still uncertain. The hypothesis of this study is that the joint use of LPP and deep NMB can reduce perioperative renal injury in diabetic patients undergoing laparoscopic pelvic surgery without impeding the view of the surgical field.MethodsThis is a double-blinded, randomized controlled trial using a 2 × 2 factorial trial design. A total of 648 diabetes patients scheduled for major laparoscopic pelvic surgeries at Peking Union Medical College Hospital will be randomized into the following four groups: SPP (12–15 mmHg) + deep-NMB (post-tetanic count of 1–2) group, LPP (7–10 mmHg) + deep-NMB group, SPP + moderate-NMB (train-of-four of 1–2) group, and LPP + moderate-NMB group. The primary outcome is serum cystatin C level measured before insufflation, after deflation, 24 h postoperatively, and 72 h postoperatively. The secondary outcomes are serum creatinine level, intraoperative urine output, erythrocytes in urinary sediment, renal tissue oxygen saturation, Leiden’s surgical condition rating scale, surgery duration, and occurrence of bucking or body movement.DiscussionThis study will provide evidence for the effect of LPP on renal function protection in patients with diabetes undergoing laparoscopic pelvic surgery. The trial can also help us to understand whether deep NMB can improve surgical conditions.Trial registrationClinicalTrials.gov: NCT04259112. Prospectively registered on 5 February 2020.

Effects of blood transfusion on regional tissue oxygenation in preterm newborns are dependent on the degree of anaemia.

Most of the preterm infants are transfused at least once during their stay in the neonatal intensive care unit (NICU). The aims of this study were to demonstrate if packed red blood cell (pRBC) transfusion modulates regional (cerebral, abdominal, renal) tissue oxygen saturation measured by near-infrared spectroscopy (NIRS) and to demonstrate if we can use NIRS to guide transfusion decisions in neonates. A multi-probe NIRS device was applied to anaemic preterm infants of gestational age <33 weeks for 30-60 min before and 24 h after pRBC transfusion. We evaluated the results separately in the subgroup with a pre-transfusion haemoglobin (Hb) < 8 g/dL. Cerebral, abdominal and renal tissue oxygen saturation (rSO2 ) and abdominal/cerebral, abdominal/renal and renal/cerebral rSO2 ratios before and 24 h after transfusion were compared. There was no significant difference in cerebral rSO2 and abdominal/renal rSO2 ratios before and 24 h after transfusion, but abdominal and renal rSO2 and abdominal/cerebral and renal/cerebral rSO2 ratios at the 24th h following transfusion increased significantly. This increase was observed in the subgroup with pre-transfusion Hb < 8 g/dL. Although statistically significant, the increase in renal oxygenation was within the limits of variability. The increase in tissue oxygenation in abdominal region after pRBC transfusion suggests decreased tissue oxygenation of intestines during severe anaemia despite cerebral oxygenation being maintained at that particular Hb level. The impact of the increase on renal oxygenation with pRBC transfusion is unclear and might need further investigation. Increase in abdominal rSO2 may cause reperfusion injury, oxidative damage and trigger necrotising enterocolitis.

Elevated renal tissue oxygenation in premature fetal growth restricted neonates: An observational study.

BackgroundFetal growth restriction (FGR) is associated with an increased risk for kidney disease in later life. Studies reporting on early signs of renal disturbances in FGR are sparse and mostly include invasive measurements, which limit the possibility for early identification and prevention. We aim to investigate whether renal tissue oxygen saturation (rSO2) measured with near-infrared spectroscopy (NIRS) and the derived value fractional tissue oxygen extraction (FTOE) differ between premature FGR and control neonates in the first three days after birth.MethodsNine FGR and seven control neonates born <32 weeks of gestation were included. FGR was defined as biometry <p10 combined with prenatal signs of placental insufficiency. Renal rSO2 was measured continuously with NIRS for 72 hours. FTOE was calculated as: (arterial saturation-rSO2)/arterial saturation. Renal artery blood flow (pulsatility and resistance index) was measured within 24 hours after birth. A linear mixed model approach was used (intercept ± slope = r) to analyze the NIRS parameters.ResultsRenal rSO2 was higher in FGR neonates compared to controls (94% vs. 83%; pgroup = 0.002). During the first three days after birth, renal rSO2 decreased in FGR neonates and increased in controls (r = -0.25 vs. r = 0.03; pinteraction = 0.001). Renal FTOE was lower in FGR neonates (0.02 vs. 0.14; pgroup = 0.01) and increased slightly during three days after birth, while it remained stable in controls (r = 0.003 vs. r = -0.0001; pinteraction = 0.001). Renal artery blood flow was similar between groups.ConclusionsFGR neonate kidneys showed higher rSO2 as measured with NIRS and lower derived values of FTOE in the first three days after birth. We speculate that this was caused by either a reduced oxygen consumption due to impaired renal maturation or increased renal oxygen supply. How these observations correlate with short- and long-term renal function needs further investigation before renal NIRS can be implemented in screening and prevention in clinical practice.

Cerebral and Renal Oxygen Saturation Are Not Compromised in the Presence of Retrograde Blood Flow in either the Ascending or Descending Aorta in Term or Near-Term Infants with Left-Sided Obstructive Lesions

Background: In infants with left-sided obstructive lesions (LSOL), the presence of retrograde blood flow in either the ascending or descending aorta may lead to diminished cerebral and renal blood flow, respectively. Objectives: Our aim was to compare cerebral and renal tissue oxygen saturation (rSO₂) between infants with LSOL with antegrade and retrograde blood flow in the ascending aorta and with and without diastolic backflow in the descending aorta. Methods: Based on 2 echocardiograms, the study group was categorized according to the direction of blood flow in the ascending and descending aorta. We measured cerebral and renal rSO₂ using near-infrared spectroscopy and calculated fractional tissue oxygen extraction (FTOE). Results: Nineteen infants with LSOL, admitted to the NICU between 0 and 28 days after birth, were included. Infants with antegrade blood flow (n = 12) and infants with retrograde blood flow in the ascending aorta (n = 7) had similar cerebral rSO₂ and FTOE during both echocardiograms. Only during the first echocardiogram, infants with retrograde blood flow in the ascending aorta had lower renal FTOE (0.14 vs. 0.32, p = 0.04) and tended to have higher renal rSO₂ (80 vs. 65%, p = 0.09). The presence of diastolic backflow in the descending aorta was not associated with cerebral or renal rSO₂ and FTOE during the first (n = 8) as well as the second echocardiogram (n = 10). Conclusions: Retrograde blood flow in the ascending aorta was not associated with cerebral oxygenation, while diastolic backflow in the descending aorta was not associated with renal oxygenation in infants with LSOL.

OP21 - Urine partial oxygen pressure as early marker of acute kidney injury after paediatric cardiac surgery

Acute kidney injury (AKI) is the common and serious complication which occurs in open-heart surgery (HS) using cardiopulmonary bypass (CPB). The renal medulla is one the first affected tissues from decreased perfusion during the procedure of cardiopulmonary bypass. Partial pressure of the urine taken from the renal pelvis is related to the perfusion of renal medulla was shown. Neutrophil gelatinase-associated lipocalin (NGAL) is accepted as an early biomarker and a predictor of AKI in a variety of clinical settings. We sought to evaluate the relationship between urine pO2 and kidney function-injury biomarkers and contribution of glycocalyx derangement after paediatric cardiac surgery. Twenty paediatric patients with normal preoperative renal function as assessed by the creatinine level, undergoing HS with CPB were included in this prospective clinical observational study. Besides routine hemodynamics and cerebral tissue oxygen saturation monitoring, patients were assessed for the partial pressure of the bladder urine (PuO2) and renal tissue oxygen saturation monitoring by NIRS intraoperatively (after induction, before CPB, after CPB) and postoperative (admission of ICU, 3rd, 6th, 9th, 12th in ICU) periodically. Additionally, syndecan-1, hyaluronan, cystatin-c, and NGAL levels were measured in plasma and urine samples. PuO2 was found wavy throughout the operation (p>0.05) and increased at the 6th (p<0.05), 9th (p<0.001) and 12th (p<0.001) hours of ICU admission. Renal tissue oxygen saturation (rSO2) monitored by NIRS was found stable throughout the operation and postoperative 12 hours. Plasma NGAL and hyaluronan levels were significantly found to rise at the 12th hour of ICU admission compared to the anaesthesia induction (p<0.001); meanwhile syndecan and cystatin-c were remained constant (p>0.05). A significant correlation between PuO2 and other measurements as renal tissue oxygen saturation (rSO2), arterial blood lactate, NGAL and hyaluronan levels was not determined at any time points. Coexistence of urine pO2 fluctuations and increment of plasma NGAL-hyaluronan levels suggest that urine pO2 could be early marker of kidney injury in paediatric patients undergoing HS. Further investigation in the role of urine pO2 plays in ischemic organ injury and its potential diagnostic implications is needed. 1. Clin Exp Pharmacol Physiol. 2008 Sep;35(9):1109-12

Near-infrared spectroscopy as a predictor of clinical deterioration: a case report of two infants with duct-dependent congenital heart disease

BackgroundSome infants with congenital heart disease are at risk of in-hospital cardiac arrest. To better foresee cardiac arrest in infants with congenital heart disease, it might be useful to continuously assess end-organ perfusion. Near-infrared spectroscopy is a non-invasive method to continuously assess multisite regional tissue oxygen saturation.Case presentationWe report on two infants with duct-dependent congenital heart disease who demonstrated a gradual change in cerebral and/or renal tissue oxygen saturation before cardiopulmonary resuscitation was required. In both cases, other clinical parameters such as heart rate, arterial oxygen saturation and blood pressure did not indicate that deterioration was imminent.ConclusionsThese two cases demonstrate that near-infrared spectroscopy might contribute to detecting a deteriorating clinical condition and might therefore be helpful in averting cardiopulmonary collapse and need for resuscitation in infants with congenital heart disease.

Use of renal near-infrared spectroscopy measurements in congenital diaphragmatic hernia patients on ECMO

IntroductionThis study tests the hypothesis that renal tissue oxygen saturation as measured by Near Infrared Spectroscopy (NIRS) would correlate with urine output in neonates with congenital diaphragmatic hernia (CDH) on extracorporeal membrane oxygenation (ECMO). MethodsBetween 2012 and 2015, neonates with CDH were enrolled as part of a comprehensive study that provided renal/cerebral/abdominal NIRS monitoring for the duration of ECMO support. Continuous NIRS measurements, mean arterial pressure, and urine output were recorded. Periods of anuria (NU), adequate urine output >1ml/kg/h (AU), and low urine output <1ml/kg/h (LU) were noted and analyzed. ResultsOver 1500h of continuous renal NIRS were obtained from six neonates. NIRS values were significantly different during periods of AU, LU, and anuria (84±6%, 76±3%, and 67±6%, p<0.01). ROC curves identified NIRS >76% as highly predictive of adequate urine output (AUC=0.96). MAP was significantly lower only in anuric patients, 36.42±10.26, compared to patients with AU and LU - 42.99±5.25 and 42.85±7.4, respectively (p<0.001). ConclusionRenal NIRS measurements correlate with urine production. Lower values are noted as urine output declines and precedes a decline in MAP. Renal NIRS may have promise as a non-invasive means of determining adequacy of renal perfusion and urine output in neonates with complex fluid shifts. Level of evidenceIIb.

Is renal tissue oxygen desaturation during severe hypoxia underestimated? An observational study in term newborn piglets.

The kidney is an organ highly susceptible to injury by regional tissue oxygen desaturation during hypoxic episodes. Transcutaneous monitoring of renal tissue oxygen saturation is therefore of increasing interest. The aim of the present study was to compare renal tissue oxygen saturation measured by near-infrared spectroscopy (NIRS) during acute hypoxia in neonates directly on the kidney and transcutaneously. We hypothesized that transcutaneous renal tissue oxygen saturation measurements would be influenced by superficial tissue. Five term newborn piglets were anesthetized, instrumented and exposed to normocapnic hypoxia at an inspired oxygen concentration of 0.14. Regional tissue oxygen saturation (rSO₂) was simultaneously measured for comparison with the sensor of NIRS (Invos 5100, Somanetics Corp., Troy, MI, USA) applied directly on the left kidney (renaldirect rSO₂) and on the skin of right flank above the right kidney (renalskin rSO₂). Cerebral regional tissue oxygenation (cerebralskin rSO₂), arterial oxygen saturation, heart rate (HR) and mean arterial pressure (MAP) were also monitored. NIRS parameters were analyzed in 5 s intervals during first 2 min of hypoxia. Hypoxia was achieved with an arterial oxygen desaturation from median (range) 95.3% (86.8-98.0) to 23.5% (13.0-41.0) after 2 min. HR and MAP did not change significantly during hypoxia. There were pronounced and lower renaldirect rSO₂ readings when compared with those of renalskin rSO₂ with significant differences from 25 to 55 s after initiation of hypoxia. Changes of cerebralskin rSO₂ and renalskin rSO₂ were similar. Transcutaneous monitoring of renal tissue oxygen saturation may underestimate acute oxygen desaturation of the kidney during hypoxia in neonates.

PS-026 Cerebral And Renal Oxygen Saturation And Extraction In Neonates With Left Ventricular Outflow Tract Obstruction

Background and aim Neonates with left ventricular outflow tract obstruction (LVOTO) are at risk of developing brain damage, due to either ischemia or hypoxemia. Our aim was to explore the differences in cerebral and renal tissue oxygen saturation (rSO 2 ) and extraction (FTOE) between neonates with LVOTO with or without compromised antegrade ascending aortic flow. Methods We included fourteen neonates with LVOTO and categorised them into neonates with compromised antegrade ascending aortic flow (hypoplastic left heart syndrome (n = 6)) and neonates without compromised antegrade ascending aortic flow (coarctatio aortae (n = 7)/non-critical aortic valve stenosis (n = 1)). We measured cerebral and renal rSO 2 using near-infrared spectroscopy during 72 h. Simultaneously, we measured preductal arterial oxygen saturation (SpO 2 ) and calculated FTOE. Results On day 1, neonates with compromised antegrade ascending aortic flow had lower cerebral rSO 2 than neonates without compromised antegrade ascending aortic flow (median rSO 2 68.5% vs. 79.4%, p-value = 0.032). Furthermore, cerebral FTOE tended to be higher in neonates with compromised antegrade ascending aortic flow on day 1 (median FTOE 0.30 vs. 0.14, p-value = 0.086). Significant differences in cerebral rSO 2 and FTOE disappeared the following days. There were no differences in SpO 2 , renal rSO 2 and FTOE between both groups. Conclusions Because there were no differences in SpO 2 between both groups, and cerebral FTOE tended to be higher in neonates with compromised antegrade ascending aortic flow, the lower cerebral oxygen saturation might be due to ischemia rather than hypoxemia. Furthermore, in neonates with antegrade ascending aortic flow, cerebral oxygenation might be spared.

Acute Kidney Injury and Renal Regional Oxygen Saturation During Aortic Arch Reconstruction in Infants

Acute kidney injury is a serious postoperative complication following cardiac surgery. The aortic arch repair technique using antegrade selective cerebral perfusion has been used, but it is unclear whether subdiaphragmatic organs such as the kidneys are perfused adequately. The authors compared intraoperative renal regional oxygen saturation using near-infrared spectroscopy between infants with and without postoperative acute kidney injury after undergoing aortic arch reconstruction. Retrospective medical records review. University medical center. Elective cardiac surgical infants. The author reviewed the perioperative clinical records of infants who underwent aortic arch reconstruction surgery using antegrade selective cerebral perfusion. During the operation, prestenotic (right radial or right brachial artery) and poststenotic (femoral or umbilical artery) invasive arterial blood pressure and cerebral and renal regional oxygen saturation were monitored continuously. Development of acute kidney injury within 72 hours of surgery was investigated. A total of 47 patients were enrolled in this study. Postoperative acute kidney injury occurred in 19 patients (40.4%). Intraoperative renal regional oxygen saturation was similar between patients with and without acute kidney injury. Intraoperative prestenotic and poststenotic mean arterial blood pressure and cerebral regional oxygen saturation also were similar between the 2 groups. The intraoperative renal tissue oxygen saturation was not different between the groups with or without postoperative acute kidney injury in infants who underwent aortic arch repair using antegrade selective cerebral perfusion.