Renal Near-infrared Spectroscopy Research Articles

The Effects of High Frequency Oscillatory Ventilation (HFOV) with Volume Guarantee (VG) on Left Ventricular Function, Systemic and Regional Oxygenation, and Ventilation When Compared to HFOV and Conventional Mechanical Ventilation (CMV) in A Newborn Piglet Model of Respiratory Distress Syndrome (RDS)

Abstract BACKGROUND: RDS due to surfactant deficiency is commonly seen in preterm infants. These infants often require ventilatory support such as CMV and HFOV. HFOV with VG (HFOV+VG) is an alternative mode that delivers a set tidal volume. There is limited data on either HFOV mode regarding the effects on left ventricular (LV) function, systemic and regional oxygenation, and ventilation. OBJECTIVES: We primarily compared the effects of CMV with VG, HFOV, and HFOV+VG on cardiac index (CI). Secondary parameters included heart rate (HR), mean arterial pressure (MAP), LV ejection fraction (EF), stroke volume (SV), dP/dt max, LV end-systolic volume and pressure (ESV, ESP), end-diastolic volume and pressure (EDV, EDP), and measures of oxygenation and ventilation. Oxygenation parameters included cerebral and renal near-infrared spectroscopy (NIRS), partial pressure of arterial oxygen (PaO2), and carotid artery flow index (CAFI). Ventilation parameters included partial pressure of arterial carbon dioxide (PaCO2) and minute ventilation (MV). DESIGN/METHODS: Piglets (1.4-2.4 kg; 1-3 days old) were acutely anesthetized and instrumented with the placement of a right femoral arterial catheter for blood gas analysis, NIRS probes (Invos®), Transonic® flow probe on right common carotid artery, and Millar® catheter in the LV. Warm saline lung lavage was performed to achieve an AaDO2 of 300-450 mmHg to simulate moderate to severe RDS. Piglets were then block-randomized to CMV, HFOV or HFOV+VG for 4 hours using a Fabian HFO ventilator (Acutronic Medical Systems AG, Switzerland)(n=8 per group). Sham-operated piglets without RDS were monitored for the same duration under CMV (n=6). Two-way repeated measures ANOVA was used to analyze the data between modes or time points. RESULTS: Piglets developed moderately severe RDS with comparable AaDO2 and Paw along with stable hemodynamic parameters. Both HFOV and HFOV+VG groups had similar PaCO2 whereas the CMV group had elevated PaCO2 when compared to that of the Sham (p<0.01). Switching to HFOV resulted in a higher MV than its baseline. HFOV+VG but not HFOV or CMV groups had lower regional oxygenation and CAFI than its respective normoxic baseline (all p<0.01). HFOV and HFOV+VG had higher CI, EF, and SV than CMV at 4 hours of recovery (p<0.05) with similar HR, MAP, dP/dt max, ESV, ESP, EDV and EDP. CONCLUSION: In our piglet model of RDS, HFOV shows benefits to LV function and ventilation when compared to CMV. HFOV+VG does not show benefits compared to HFOV.

A Decline in Intraoperative Renal Near-Infrared Spectroscopy Is Associated With Adverse Outcomes in Children Following Cardiac Surgery.

Renal near-infrared spectroscopy is known to be predictive of acute kidney injury in children following cardiac surgery using a series of complex equations and area under the curve. This study was performed to determine if a greater than or equal to 20% reduction in renal near-infrared spectroscopy for 20 consecutive minutes intraoperatively or within the first 24 postoperative hours is associated with 1) acute kidney injury, 2) increased acute kidney injury biomarkers, or 3) other adverse clinical outcomes in children following cardiac surgery. Prospective single center observational study. Pediatric cardiac ICU. Children less than or equal to age 4 years who underwent cardiac surgery with the use of cardiopulmonary bypass during the study period (June 2011-July 2012). None. A reduction in near-infrared spectroscopy was not associated with acute kidney injury. Nine of 12 patients (75%) with a reduction in renal near-infrared spectroscopy did not develop acute kidney injury. The remaining three patients had mild acute kidney injury (pediatric Risk, Injury, Failure, Loss, End stage-Risk). A reduction in renal near-infrared spectroscopy was associated with the following adverse clinical outcomes: 1) a longer duration of mechanical ventilation (p = 0.05), 2) longer intensive care length of stay (p = 0.05), and 3) longer hospital length of stay (p < 0.01). A decline in renal near-infrared spectroscopy in combination with an increase in serum interleukin-6 and serum interleukin-8 was associated with a longer intensive care length of stay, and the addition of urine interleukin-18 to this was associated with a longer hospital length of stay. In this cohort, the rate of acute kidney injury was much lower than anticipated thereby limiting the evaluation of a reduction in renal near-infrared spectroscopy as a predictor of acute kidney injury. A greater than or equal to 20% reduction in renal near-infrared spectroscopy was significantly associated with adverse outcomes in children following cardiac surgery. The addition of specific biomarkers to the model was predictive of worse outcomes in these patients. Thus, real-time evaluation of renal near-infrared spectroscopy using the specific levels of change of a 20% reduction for 20 minutes may be useful in predicting prolonged mechanical ventilation and other adverse outcomes in children undergoing cardiac surgery.

Clinical Factors Associated with Dose of Loop Diuretics After Pediatric Cardiac Surgery: Post Hoc Analysis.

A post hoc analysis of a randomized controlled trial comparing the clinical effects of furosemide and ethacrynic acid was conducted. Infants undergoing cardiac surgery with cardiopulmonary bypass were included in order to explore which clinical factors are associated with diuretic dose in infants with congenital heart disease. Overall, 67 patients with median (interquartile range) age of 48 (13-139) days were enrolled. Median diuretic dose was 0.34 (0.25-0.4) mg/kg/h at the end of postoperative day (POD) 0 and it significantly decreased (p=0.04) over the following PODs; during this period, the ratio between urine output and diuretic dose increased significantly (p=0.04). Age (r -0.26, p=0.02), weight (r -0.28, p=0.01), cross-clamp time (r 0.27, p=0.03), administration of ethacrynic acid (OR 0.01, p=0.03), and, at the end of POD0, creatinine levels (r 0.3, p=0.009), renal near-infrared spectroscopy saturation (-0.44, p=0.008), whole-blood neutrophil gelatinase-associated lipocalin levels (r 0.30, p=0.01), pH (r -0.26, p=0.02), urinary volume (r -0.2755, p=0.03), and fluid balance (r 0.2577, p=0.0266) showed a significant association with diuretic dose. At multivariable logistic regression cross-clamp time (OR 1.007, p=0.04), use of ethacrynic acid (OR 0.2, p=0.01) and blood pH at the end of POD0 (OR 0.0001, p=0.03) was independently associated with diuretic dose. Early resistance to loop diuretics continuous infusion is evident in post-cardiac surgery infants: Higher doses are administered to patients with lower urinary output. Independently associated variables with diuretic dose in our population appeared to be cross-clamping time, the administration of ethacrynic acid, and blood pH.

Intraoperative renal near-infrared spectroscopy indicates developing acute kidney injury in infants undergoing cardiac surgery with cardiopulmonary bypass: a case-control study.

IntroductionAcute kidney injury (AKI) is a frequent complication after cardiac surgery with cardiopulmonary bypass in infants. Renal near-infrared spectroscopy (NIRS) is used to evaluate regional oximetry in a non-invasive continuous real-time fashion, and reflects tissue perfusion. The aim of this study was to evaluate the relationship between renal oximetry and development of AKI in the operative and post-operative setting in infants undergoing cardiopulmonary bypass surgery.MethodsIn this prospective study, we enrolled 59 infants undergoing cardiopulmonary bypass surgery for congenital heart disease for univentricular (n = 26) or biventricular (n = 33) repair. Renal NIRS was continuously measured intraoperatively and for at least 24 hours postoperatively and analysed for the intraoperative and first 12 hours, first 24 hours and first 48 hours postoperatively. The renal oximetry values were correlated with the paediatric risk, injury, failure, loss, end (pRIFLE) classification for AKI, renal biomarkers and the postoperative course.ResultsTwenty-eight (48%) infants developed AKI based on pRIFLE classification. Already during intraoperative renal oximetry and further in the first 12 hours, 24 hours and 48 hours postoperatively, significantly lower renal oximetry values in AKI patients compared with patients with normal renal function were recorded (P < 0.05). Of the 28 patients who developed AKI, 3 (11%) needed renal replacement therapy and 2 (7%) died. In the non-AKI group, no deaths occurred. Infants with decreased renal oximetry values developed significantly higher lactate levels 24 hours after surgery. Cystatin C was a late parameter of AKI, and neutrophil gelatinase-associated lipocalin values were not correlated with AKI occurrence.ConclusionOur results suggest that prolonged low renal oximetry values during cardiac surgery correlate with the development of AKI and may be superior to conventional biochemical markers. Renal NIRS might be a promising non-invasive tool of multimodal monitoring of kidney function and developing AKI in infants undergoing cardiac surgery with cardiopulmonary bypass.

Combined Cerebral and Renal Near-Infrared Spectroscopy After Congenital Heart Surgery.

The maintenance of an adequate oxygen supply to tissues after congenital heart surgery is essential for good outcomes. The objective of this study was to assess the usefulness of near-infrared spectroscopy (NIRS) for estimating central venous oxygen saturation (ScvO2) using both cerebral and renal measurements, explore its relation with cardiac output measurements and check its ability to detect low cardiac output. A prospective observational pilot study was conducted in patients weighing <10 kg undergoing cardiopulmonary bypass surgery. Spectroscopy probes were placed on the forehead and renal area, and serial cardiac output measurements were obtained by femoral transpulmonary thermodilution over the first 24 h after surgery. In the 15 patients studied, ScvO2 was correlated with cerebral (r = 0.58), renal (r = 0.60) and combined (r = 0.71) measurements. Likewise, the systolic index was correlated with the NIRS signals: cerebral (r = 0.60), renal (r = 0.50) and combined (r = 0.66). Statistically significant differences were found in the NIRS measures registered in the 29 low cardiac output events detected by thermodilution: cerebral: 62 % (59-65) versus 69 % (63-76); renal: 83 % (70-89) versus 89 % (83-95); and combined 64 % (60-69) versus 72 % (67-76). In our series, combined cerebral and renal monitoring was correlated with central venous oxygen saturation and cardiac output; low cardiac output detection associated a different spectroscopy pattern.

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Background and aims: Acute kidney injury (AKI) is a frequent complication after cardiac surgery with cardiopulmonary bypass in infants. Renal near-infrared spectroscopy (NIRS) evaluates regional oximetry in a non-invasive continuous fashion and reflects tissue perfusion. Aims: The aim of this study was to evaluate the relation between renal oximetry and development of AKI in infants undergoing cardiopulmonary surgery. Methods: We prospectively enrolled 59 infants undergoing cardiopulmonary bypass surgery for uni- (n = 26) or biventricular (n = 33) repair. IRB approval was given and parents signed written informed consent. Renal NIRS was continuously measured intraoperatively and at least 24 hours postoperatively. Renal oximetry values were correlated with the pediatric Renal-Injury-Failure-Loss-End (pRIFLE) classification for AKI, renal biomarkers and the postoperative course. Results: 28 (48 %) infants developed AKI. Already in the intraoperative renal oximetry and further in the first 12, 24 and 48 hours postoperatively significantly lower renal oximetry values in AKI patients as compared to patients with normal renal function could be shown (p < 0.05). 11 % (3/28) of infants with AKI needed renal replacement therapy and 2/28 (7 %) died. In the non AKI group no fatal course occurred. Infants with decreased renal oximetry values developed significantly higher lactate levels 24 hours after surgery. NGAL values were not correlated with AKI. Conclusions: Our results suggest that prolonged lower renal oximetry values during cardiac surgery correlate with the development of AKI and are superior to conventional biomarkers. Renal NIRS is a promising tool to develop kidney-protective strategies during cardiac surgery with cardiopulmonary bypass in infants.

Inferior Vena Cava Oxygen Saturation Monitoring After the Norwood Procedure

Superior vena cava oxygen saturation monitoring in the early postoperative period after the Norwood procedure (NP) has been associated with improved survival and decreased adverse events (AE). There is no data describing inferior vena cava saturation (Sivo2) monitoring after NP. We sought to investigate the utility of intermittent Sivo2 monitoring after NP and to assess the correlation of Sivo2 with renal near-infrared spectroscopy (rNIRS). We hypothesized failure to achieve Sivo2 greater than 45% within the first 4 hours after NP is predictive of AE, and that rNIRS correlates with Sivo2. A retrospective study of 26 consecutive NP patients who received postoperative management with Sivo2 monitoring according to a strict protocol was conducted. Primary outcome was AE, defined as cardiopulmonary resuscitation, extracorporeal membrane oxygenation, death before discharge, or residual surgical defects. Ten (38%) patients had one or more AE; mortality was 23%. On admission to the cardiac intensive care unit, patients with AE had lower Sivo2 (45% ± 9.4% versus 62% ± 12.0%; p < 0.001) and lower rNIRS (56 ± 6.5 versus 77 ± 7.2; p < 0.001). At 4 hours, 90% of AE patients had an Sivo2 less than 45% versus 6% of non-AE patients. Both Sivo2 and rNIRS were highly predictive of AE: the area under the receiver-operating characteristic curve was greater than 0.86 and 0.95, respectively. Two hours after admission, an Sivo2 less than 45% predicted AE with a specificity of 93%, a sensitivity of 70%, and a positive predictive value of 82%. The Sivo2 was strongly correlated with rNIRS (r = 0.81). Intermittent Sivo2 can be used to guide early postoperative NP management; rNIRS is an accurate continuous, noninvasive surrogate for Sivo2. An Sivo2 of less than 45% in the first 4 hours after the NP is predictive of AE.

Urinary biomarkers and renal near-infrared spectroscopy predict intensive care unit outcomes after cardiac surgery in infants younger than 6 months of age

To assess the ability of urinary acute kidney injury biomarkers and renal near-infrared spectroscopy (NIRS) to predict outcomes in infants after surgery for congenital heart disease. Urinary levels of neutrophil gelatinase-associated lipocalin (NGAL), interleukin-18 (IL-18), kidney injury molecule-1 (KIM-1), and cystatin C were measured preoperatively and postoperatively in 49 infants younger than 6 months of age. Renal NIRS was monitored for the first 24 hours after surgery. A composite poor outcome was defined as death, the need for renal replacement therapy, prolonged time to first extubation, or prolonged intensive care unit length of stay. Forty-two (86%) patients had acute kidney injury as indicated by at least Acute Kidney Injury Network/Kidney Disease: Improving Global Outcomes (AKIN/KDIGO) stage 1 criteria, and 17 (35%) patients had poor outcomes, including 3 deaths. With the exception of KIM-1, all biomarkers demonstrated significant increases within 24 hours postoperatively among patients with poor outcomes. Low levels of NGAL and IL-18 demonstrated high negative predictive values (91%) within 2 hours postoperatively. Poor outcome infants had greater cumulative time with NIRS saturations less than 50% (60 vs 1.5 minutes; P=.02) in the first 24 hours. Within the first 24 hours after cardiopulmonary bypass, infants at increased risk for poor outcomes demonstrated elevated urinary NGAL, IL-18, and cystatin C and increased time with low NIRS saturations. These findings suggest that urinary biomarkers and renal NIRS may differentiate patients with good versus poor outcomes in the early postoperative period, which could assist clinicians when counseling families and inform the development of future clinical trials.

Change in regional (somatic) near-infrared spectroscopy is not a useful indictor of clinically detectable low cardiac output in children after surgery for congenital heart defects

Near-infrared spectroscopy correlation with low cardiac output has not been validated. Our objective was to determine role of splanchnic and/or renal oxygenation monitoring using near-infrared spectroscopy for detection of low cardiac output in children after surgery for congenital heart defects. Prospective observational study. Pediatric intensive care unit of a tertiary care teaching hospital. Children admitted to the pediatric intensive care unit after surgery for congenital heart defects. None. We hypothesized that splanchnic and/or renal hypoxemia detected by near-infrared spectroscopy is a marker of low cardiac output after pediatric cardiac surgery. Patients admitted after cardiac surgery to the pediatric intensive care unit over a 10-month period underwent serial splanchnic and renal near-infrared spectroscopy measurements until extubation. Baseline near-infrared spectroscopy values were recorded in the first postoperative hour. A near-infrared spectroscopy event was a priori defined as ≥20% drop in splanchnic and/or renal oxygen saturation from baseline during any hour of the study. Low cardiac output was defined as metabolic acidosis (pH <7.25, lactate >2 mmol/L, or base excess ≤-5), oliguria (urine output <1 mL/kg/hr), or escalation of inotropic support. Receiver operating characteristic analysis was performed using near-infrared spectroscopy event as a diagnostic test for low cardiac output. Twenty children were enrolled: median age was 5 months; median Risk Adjustment for Congenital Heart Surgery category was 3 (1-6); median bypass and cross-clamp times were 120 mins (45-300 mins) and 88 mins (17-157 mins), respectively. Thirty-one episodes of low cardiac output and 273 near-infrared spectroscopy events were observed in 17 patients. The sensitivity and specificity of a near-infrared spectroscopy event as an indicator of low cardiac output were 48% (30%-66%) and 67% (64%-70%), respectively. On receiver operating characteristic analysis, neither splanchnic nor renal near-infrared spectroscopy event had a significant area under the curve for prediction of low cardiac output (area under the curve: splanchnic 0.45 [95% confidence interval 0.30-0.60], renal 0.51 [95% confidence interval 0.37-0.65]). Splanchnic and/or renal hypoxemia as detected by near-infrared spectroscopy may not be an accurate indicator of low cardiac output after surgery for congenital heart defects.

Near-Infrared Spectroscopy Monitoring to Predict Postoperative Renal Insufficiency Following Repair of Congenital Heart Disease

Infants undergoing repair or palliation of congenital heart disease are at risk of renal insufficiency. Development of renal insufficiency increases mortality. This project seeks to determine whether intra- and postoperative renal near-infrared spectroscopy (NIRS) monitoring can reliably predict renal insufficiency after cardiac surgery in infants. In this prospective, observational cohort study 48 patients undergoing repair or palliation of congenital heart disease in the first 6 months of life were studied intraoperatively and on postoperative day 1 and 2. The NIRS mean and nadir were recorded for the 3 time periods, as were urine output, fluid balance, and serum creatinine. Renal insufficiency was defined as rise in creatinine ≥40% from baseline or oliguria for >4 hours. Near-infrared spectroscopy data were compared to creatinine increase, oliguria, and fluid balance on postoperative day 0, 1, and 2 by regression analysis. Mean renal regional saturation on postoperative day 1 has a strong correlation with increase in creatinine (P < .001 and R (2) = .6). Mean renal saturation less than 80% predicts renal insufficiency with a sensitivity of 100% and a specificity of 75% (P < .001). Monitoring of intra- and postoperative renal regional saturation may provide an early, noninvasive marker of renal insufficiency after cardiac surgery in infants. This would be clinically significant if interventions to improve renal regional saturation prevent renal insufficiency.