Splanchnic Oxygen Saturation Research Articles

Changes in adequacy of splanchnic oxygen delivery and splanchnic artery doppler after bolus feedings in infants: a systematic review and meta-analysis

BackgroundCurrent practice regarding timing of feed initiation and feed tolerance largely relies on anecdotal practice and protocols. This study aims to provide an objective measure to guide clinical practice by analyzing changes in splanchnic regional oxygen saturation and Doppler patterns with feeds. MethodsA systematic review was performed. Inclusion criteria were: 1) patients under 1 year of age; 2) splanchnic regional oxygen saturation with near infrared spectroscopy before and after feeds or mesenteric Doppler findings before and after feeds; and 3) clinical parameters must have been presented as either mean and standard deviation or median and range. Endpoints of interest included splanchnic regional oxygen saturation, splanchnic systolic velocity, and splanchnic diastolic velocity. Meta-analyses were conducted using an inverse-variance model. The pooled effects are reported as mean difference and 95% confidence interval. Meta-regression was conducted for each endpoint with the following independent variables entered into the model: study year, gestational age, birth weight, time to measurement, and age at time of study. ResultsThis study included 8 studies with a total of 240 patients. Splanchnic regional oxygen saturation did not significantly differ after feeds (mean difference +1.0, 95% CI -2.9 to 4.9, p-value 0.62). Sensitivity analyses demonstrated that gestational age under 28 weeks was associated with a significant decrease in splanchnic regional oxygen saturation and GA over 30 weeks was not. Splanchnic artery systolic velocity was significantly higher after feeds (mean difference +34.0 cm/s, 95% CI 11.1 to 57.0 cm/s, p-value < 0.01). Sensitivity analyses for gestational age and birth weight did not find any significant difference in pooled effect. ConclusionSplanchnic regional oxygen saturation was significantly decreased after feeds in those patients under 28 weeks of gestation compared to those over 30 weeks. Systolic and diastolic Doppler velocities were significantly higher after feeds without differences in gestational age.

Safety of different concentrations of glycerine enema for meconium evacuation in preterm infants: study protocol for a randomised controlled trial

IntroductionVarious approaches are employed to expedite the passage of meconium in preterm infants within the neonatal intensive care unit (NICU), with glycerine enemas being the most frequently used. Due to...

Ischemia modified albumin as a marker of hypoxia in preterm infants in the first week after birth

BackgroundTissue hypoxia remains a leading cause of morbidity and mortality in preterm infants. Current biomarkers often detect irreversible hypoxic cellular injury (i.e. lactate) and are non-specific. A new biomarker is needed which detects tissue hypoxia before irreversible damage occurs. AimsTo investigate the relation between serum ischemia modified albumin (IMA), a marker of hypoxia; and analytic variables, patient related variables and conditions associated with hypoxia, in preterm infants. Study designRetrospective cohort study. SubjectsInfants with a gestational age < 30 weeks and/or birth weight < 1000 g. Outcome measuresWe collected two remnant blood samples in the first week after birth and measured IMA. IMA/albumin ratio (IMAR) was used to adjust for albumin. We assessed correlations between IMA(R) and analytic variables (albumin, lipemia- and haemolysis index); mean-2 h SpO2; mean-2 h variability of regional splanchnic oxygen saturation (rsSO2), measured using near-infrared spectroscopy; and patent ductus arteriosus (PDA). ResultsSixty-five infants were included. Albumin, the lipemia- and haemolysis index correlated negatively with IMA (r:-0.620, P<0.001; r:-0.458, P<0.001; and r:-0.337, P=0.002). IMAR correlated negatively with SpO2 (rho:-0.614, P<0.001). Lower rsSO2 variability correlated with higher IMAR values (rho:-0.785, n=14, P=0.001 and rho:-0.773, n=11, P=0.005). Infants with a hemodynamic significant PDA (hsPDA) had higher IMAR values than infants without PDA (0.13 [0.11–0.28], n=16 vs. 0.11 [0.08–0.20], n=29, P=0.005 and 0.11 [0.09–0.18], n=13 vs. 0.09 [0.06–0.17], n=37, P=0.026). ConclusionsWhen adjusted for albumin, the lipemia- and haemolysis index, IMAR has potential value as a marker for systemic hypoxia in preterm infants, considering the associations with SpO2, variability of rsSO2, and hsPDA.

The short-term effects of RBC transfusions on intestinal injury in preterm infants.

BackgroundAnemic preterm infants may require red blood cell (RBC) transfusions to maintain sufficient oxygen supply to vital organs. Transfusion treatment, however, may have adverse intestinal effects. We aimed to investigate the short-term effects of RBC transfusions, hypothesizing to find signs of oxidative stress and intestinal injury, possibly related to levels of splanchnic (re-)oxygenation.MethodsWe prospectively included preterm infants (gestational age < 32 weeks). We measured urinary biomarkers for oxidative stress (8-isoprostane) and intestinal cell injury (intestinal fatty acid-binding protein, I-FABP) shortly before and after RBC transfusion. Splanchnic oxygen saturation (rsSO2) and rsSO2 variability were assessed simultaneously.ResultsTwenty-nine preterm infants received 58 RBC transfusions at various postnatal ages. Six of them developed necrotizing enterocolitis (NEC) after transfusion. Urinary 8-isoprostane and I-FABP increased following RBC transfusion (median 282–606 pg/ml and 4732–6968 pg/ml, p < 0.01), more pronounced in infants who developed NEC. Change in I-FABP correlated with change in 8-isoprostane (rho = 0.623, p < 0.01). Lower rsSO2 variability, but not higher mean rsSO2 was associated with higher 8-isoprostane and I-FABP levels after transfusion.ConclusionsPreterm RBC transfusions are associated with concomitant signs of oxidative stress and intestinal injury, parallel with lower variability in splanchnic oxygenation. This may represent the early pathogenetic process of transfusion-associated NEC.Impact Red blood cell (RBC) transfusions in preterm infants are associated with a near 2-fold increase in urinary biomarkers for oxidative stress (8-isoprostane) and intestinal cell injury (intestinal fatty acid-binding protein, I-FABP).Magnitude of change in I-FABP strongly correlated with the magnitude of 8-isoprostane change, suggesting a role for oxidative stress in the pathogenesis of intestinal injury.Lower splanchnic oxygen saturation variability following RBC transfusion was associated with higher 8-isoprostane and I-FABP levels.Loss of splanchnic variability after RBC transfusion may result from increased oxidative stress and its concomitant intestinal injury, possibly representing the early pathogenetic process of transfusion-associated necrotizing enterocolitis.

Regional cerebral and splanchnic tissue oxygen saturation in preterm infants – Longitudinal normative measurements

BackgroundTo investigate regional splanchnic and cerebral tissue oxygen saturation in preterm infants <30 weeks gestation. MethodsCerebral (cTOI) and splanchnic (sTOI) Tissue Oxygenation Index were measured weekly in 5 min epochs for a total period of 60 min using NIRS (NIRO-300) for the first 8 weeks of life, in 48 appropriately grown preterm infants born at <30 weeks gestation. Infants who developed HPI and/or NEC (n = 12) and those that died (n = 1) were excluded from our main outcome measure of regional gut and cerebral tissue oxygenation in healthy preterm infants <30 weeks gestation. ResultsMedian birthweight 789 g (460–1486), gestational age 25+6 weeks (23+0–29+1) and 51.4% female. 217 NIRS measurements were completed across the first 8 weeks of life. Mean weekly cTOI ranged from 56.8–65.4% and sTOI ranged from 36.7–46.0%. Mean cTOI was significantly higher than mean sTOI (p < 0.001) throughout the first 8 weeks of life. Mean cTOI decreased significantly with increasing postnatal age [−0.59% each week (−1.26% to −0.07%) p = 0.04]. None of the examined confounding factors had a significant effect. ConclusionsThis is the first report of regional cerebral and splanchnic tissue oxygen saturation ranges during the first 8 weeks of life for preterm infants born at <30 weeks gestation.

Neonatal anemia relates to intestinal injury in preterm infants.

BackgroundAnemia is associated with decreased tissue oxygenation in preterm infants and may contribute to developing necrotizing enterocolitis (NEC). We aimed to investigate whether hemoglobin level is associated with intestinal injury, by comparing anemic infants 10 days prior to red blood cell (RBC) transfusion with non-anemic controls.MethodsA nested case–control study in which we matched anemic preterms (gestational age (GA) < 32 weeks) with non-anemic controls (1:1), based on GA, birth weight (BW), and postnatal age. We measured urinary intestinal fatty acid-binding protein, I-FABP, marker for intestinal injury, twice weekly. Simultaneously, we assessed splanchnic oxygen saturation (rsSO2) and rsSO2 variability.ResultsThirty-six cases and 36 controls were included (median GA 27.6 weeks, BW 1020 grams). Median I-FABP level was higher in cases from 6 days to 24-h before transfusion (median ranging: 4749–8064 pg/ml versus 2194–3751 pg/ml). RsSO2 and rsSO2 variability were lower in cases than controls shortly before transfusion. Hemoglobin levels correlated negatively with rsSO2 and rsSO2 variability in cases, and negatively with I-FABP in cases and controls together.ConclusionsUrinary I-FABP levels were higher in anemic infants before RBC transfusion than in non-anemic matched controls, suggesting intestinal injury associated with anemia. This may predispose to NEC in some anemic preterm infants.Impact Anemia is a common comorbidity in preterm infants and may lead to impaired splanchnic oxygen saturation and intestinal tissue hypoxia, a proposed mechanism for NEC.Lower hemoglobin level is associated with higher urinary I-FABP levels, a marker for intestinal injury, both in anemic preterm infants and in cases and controls together.Lower splanchnic oxygen saturation and reduction of its variability are associated with higher urinary I-FABP levels in anemic preterm infants before their first RBC transfusion.These results support the hypothesis that anemia in very preterm infants results in intestinal cell injury, which may precede NEC development in some.

Splanchnic oxygen saturation during reoxygenation with 21% or 100% O2 in newborn piglets.

Increasing evidence recognizes the harm of excess oxygen to lungs, eyes, and brain of preterm infants, but not yet to the intestine. We assessed changes in splanchnic oxygenation during reoxygenation with 21% compared to 100% O2 in a newborn piglet model of perinatal asphyxia. We randomized 25 piglets to control or intervention. Intervention groups underwent global hypoxia until acidosis and hypotension occurred. Piglets were reoxygenated for 30 min with 21% or 100% O2 and observed for 9 h. We continuously measured regional splanchnic oxygen saturation (rsSO2) using near-infrared spectroscopy (NIRS). We calculated mean rsSO2 and rsCoVar (as SD/mean). We measured PaO2 and SaO2, sampled from the right carotid artery. Reoxygenation after global hypoxia restored rsSO2. Reoxygenation with 100% O2 increased rsSO2 to values significantly higher than baseline. In intervention groups, rsCoVar decreased during observation compared to baseline. We found a correlation between rsSO2 and PaO2 (r = 0.420, P < 0.001) and between rsSO2 and SaO2 (r = 0.648, P < 0.001) in pooled data from the entire experiment. Reoxygenation after global hypoxia improves splanchnic oxygenation, but is associated with reduced variability of rsSO2. Reoxygenation with 100% O2 exposes the intestine to hyperoxia. Splanchnic NIRS is able to detect intestinal hypoxia and hyperoxia. Splanchnic oxygenation improves during reoxygenation after global hypoxia, though reoxygenation with 100% O2 exposes the intestine to hyperoxia. Decreased variability of splanchnic oxygenation several hours after hypoxia and reoxygenation seems to be independent of the resuscitation strategy, and may indicate intestinal injury. Splanchnic NIRS monitoring was able to detect intestinal hypoxia and exposure to hyperoxia, as evidenced by a strong correlation between splanchnic oxygenation and arterial oxygen content.

Regional splanchnic oxygen saturation for preterm infants in the first week after birth: reference values.

Near-infrared spectroscopy is used in the assessment of regional splanchnic oxygen saturation (rsSO2), but solid reference values are scarce. We aimed to establish reference values of rsSO2 for preterm infants during the first week after birth, both crude and modeled based on predictors. We included infants with gestational age (GA) <32 weeks and/or birth weight <1200 g. We excluded infants who developed necrotizing enterocolitis or sepsis or who died. In the first week after birth, we determined a daily 2-h mean of rsSO2 to assess its associations with sex, GA, postnatal age (PNA), small-for-gestational age (SGA) status, patent ductus arteriosus, hemoglobin, nutrition, and head circumference at birth and translated those into a prediction model. We included 220 infants. On day 1, the mean ± SD rsSO2 value was 48.2% ± 16.6. The nadir of rsSO2 was on day 4 (38.7% ± 16.6 smoothed line) to 5 (37.4%±17.3, actual data), after which rsSO2 increased to 44.2% ± 16.6 on day 7. The final model of the reference values of rsSO2 included the following coefficients: rsSO2 = 3.2 - 7.0 × PNA + 0.8 × PNA2 - 4.0 × SGA + 1.8 × GA. We established reference values of rsSO2 for preterm infants during the first week after birth. GA, PNA, and SGA affect these values and need to be taken into account. Regional splanchnic oxygen saturation is lower in infants with a lower gestational age and in small-for-gestational age infants. Regional splanchnic oxygen saturation decreases with a higher postnatal age until day 4 after birth and then increases until day 7 after birth. Gestational age, postnatal age, and small-for-gestational age status affect regional splanchnic oxygen saturation and need to be taken into account when interpreting regional splanchnic oxygen saturations using NIRS. Reference values for infant regional splanchnic oxygen saturation can be computed with a formula based on these variables, as provided by this study.

Near-infrared spectroscopy as a diagnostic tool for necrotizing enterocolitis in preterm infants.

We aimed to investigate whether splanchnic tissue oxygen saturation (rsSO2) measured by near-infrared spectroscopy (NIRS) could contribute to the early diagnosis of necrotizing enterocolitis (NEC). We retrospectively included infants with suspected NEC, gestational age <32 weeks and/or birth weight <1200 g in the first 3 weeks after birth. We calculated mean rsSO2, cerebral tissue oxygen saturation (rcSO2), variability of rsSO2 (coefficients of variation [rsCoVAR] = SD/mean), and splanchnic-cerebral oxygenation ratio ([SCOR] = rsSO2/rcSO2) in the period around the abdominal radiograph to confirm or reject NEC. Of the 75 infants, 21 (28%) had NEC (Bell's stage ≥2). Characteristics of infants with and without NEC differed only on mechanical ventilation and nil-per-os status. RsSO2 tended to be higher and rcSO2 lower in infants with NEC. RsCoVAR (median [range]) was lower (0.11 [0.03-0.34]) vs. 0.20 [0.01-0.52], P = 0.002) and SCOR higher (0.64 [0.37-1.36]) vs. 0.47 [0.16-1.09], P = 0.004) in NEC infants. Adjusted for postnatal age, mechanical ventilation, and nil-per-os status, a 0.1 higher rsCoVAR decreased the likelihood of NEC diagnosis with likelihood ratio (LR) 0.38 (95% CI 0.18-0.78) and a 0.1 higher SCOR increased it with LR 1.28 (1.02-1.61). Using NIRS, high SCOR may confirm NEC and high variability of rsSO2 may rule out NEC, when suspicion arises. Near-infrared spectroscopy may contribute to the diagnosis of necrotizing enterocolitis. When clinical signs are present a high splanchnic-cerebral oxygenation may indicate necrotizing enterocolitis. A low splanchnic-cerebral oxygenation ratio and high variability of splanchnic tissue oxygen saturation may rule out necrotizing enterocolitis. Whether a bedside real-time availability of the splanchnic-cerebral oxygenation ratio and variability of splanchnic tissue oxygen saturation improves NEC diagnosis needs to be further investigated.

Influence of altitude on cerebral and splanchnic oxygen saturation in critically ill children during air ambulance transport.

The aim of the current study was to investigate how cerebral and splanchnic oxygen saturation (rSO2-C and rSO2-A) in critically ill children transported in air ambulance was affected by flight with cabin pressurization corresponding to ≥ 5000 feet. A second aim was to investigate any differences between cyanotic and non-cyanotic children in relation to cerebral and splanchnic oxygen saturation during flight ≥ 5000 feet. The variability of the cerebral and splanchnic Near Infrared Spectroscopy (NIRS) sensors was evaluated. NIRS was used to measure rSO2-C and rSO2-A during transport of critically ill children in air ambulance. rSO2 data was collected and stored by the NIRS monitor and extracted and analyzed off-line after the transport. Prior to evaluation of the NIRS signals all zero and floor-effect values were removed. The Pediatric Intensive Care Unit (PICU) at Astrid Lindgren Children's Hospital, Karolinska University Hospital in Stockholm, Sweden. In total, 44 critically ill children scheduled for inter-hospital transport by a specialized pediatric transport team were included in the study between January 2014 and January 2019 (convenience sampling). No interventions were conducted. All study patients were monitored with a cerebral NIRS-sensor placed over the forehead and an abdominal NIRS-sensor placed in the infra-umbilical area for cerebral and splanchnic regional oxygen saturation monitoring, rSO2-C and rSO2-A, respectively. Complete rSO2-C and rSO2-A data was obtained in 39 patients. Median age was 12 days. Cyanotic congenital heart malformations were present in 9 patients (23%). In 22 patients (56%) rSO2-C decreased at altitude ≥ 5000 feet and in 24 patients (61%) rSO2-A decreased at altitude ≥ 5000 feet compared to baseline (p<0.0001). In 25 patients (64%) the rSO2-C/rSO2-A ratio was greater at altitude ≥ 5000 feet than at baseline. A ratio ≥ 1 was seen in 77% of patients at altitude ≥ 5000 feet compared to in 67% of patients at baseline. Both cerebral and splanchnic oxygen saturation decreased at altitude ≥ 5000 feet compared to baseline. In most patients, both cyanotic and non-cyanotic, cerebral oxygen saturation was preserved more than splanchnic oxygen saturation.

Effects of Caffeine on Splanchnic Oxygenation in Preterm Infants

The aim of this study is to assess the effects of administering 20 mg/kg loading dose of caffeine citrate intravenously on splanchnic oxygenation in preterm infants. The infants with a gestational age (GA) of <34 weeks who were administered with a 20 mg/kg intravenous loading dose of caffeine citrate within 48 hours after birth were investigated prospectively. Regional splanchnic oxygen saturation (rsSO2) and splanchnic fractional tissue oxygen extraction rate (sFTOE) were measured using near-infrared spectroscopy before caffeine infusion, immediately after caffeine infusion and 1, 2, 3, 4, and 6 hours (h) after dose completion; postdose values were compared with predose values. A total of 41 infants with a mean GA of 29.2 ± 1.6 weeks and birth weight of 1,315 ± 257 g as well as postnatal age of 32.2 ± 10.8 hours were included in the study. rsSO2 significantly reduced from 63.1 to 57.5% immediately after caffeine infusion, 55.1% after 1 hour, and 55.2% after 2 hours with partial recovery at 3-hour postdose. sFTOE increased correspondingly. Caffeine reduces splanchnic oxygenation and increases splanchnic oxygen extraction for at least 2 hours with partial recovery to predose levels at 3-hour postdose.

Future evolution of intraoperative goal directed fluid and hemodynamic therapy in children

Background: Recently a systematic review and meta-analysis was conducted to determine the impact of intraoperative goal directed fluid and hemodynamic therapy (GDFHT) in children and postoperative outcome. This study is part of a vast and extended Thesis Project concerning the impact of Goal Directed therapies on postoperative outcome in the pediatric population. This systematic review and meta-analysis of 23 randomized and non randomized controlled trials in 3389 children, of which more than 90% of the studies (21 among the 23 studies) concerned pediatric cardiac surgical patients, revealed that trials where GDFHT aiming to determine the impact on postoperative outcome in children were not developed compared to what has been realized in adults. However this trial showed that a lot of studies concerning hemodynamic monitoring in children were prospective, retrospective, observational and non interventional. These studies demonstrated the existence of parameters or biomarkers of adverse postoperative outcome in pediatric cardiac surgical patients. Namely cerebral, renal, splanchnic regional oxygen saturation, serum lactate levels, mixed central venous oxygen saturation and arterial to venous carbon dioxide difference. Systematic reviews and meta-analysis with high level evidence studies can help to elaborate recommendations for improvement implementation programs for clinical practice. Objective of this Editorial: To analyze the results, conclusions and future perspective of this recent systematic review and meta-analysis of the impact of intraoperative GDFHT on postoperative outcome in children. Methods: Editorial concerning the recent systemetic review and meta-analysis of the impact of intraoperative GDFHT on postoperative outcome in children. Results and Conclusion: This systematic review and meta-analysis of 23 non randomized and randomized controlled trials (RCT) evidenced that randomized controlled trials concerning the impact on perioperative GDFHT on postoperative outcome in children are lacking. Secondly, unoptimal intraoperative parameters mentioned above were predictors of adverse postoperative outcome in pediatric cardiac surgical patients. Finally RCT using these parameters in GDFHT protocols should be developed to clarify the influence of this therapy on postoperative outcome in children in cardiac and non cardiac surgical pediatric populations. In the present time there are no answers concerning the effect of intraoperative GDFHT on postoperative outcome in children. Thus research in this field is highly recommended.

Low Abdominal NIRS Values and Elevated Plasma Intestinal Fatty Acid-Binding Protein in a Premature Piglet Model of Necrotizing Enterocolitis.

To identify early markers of necrotizing enterocolitis (NEC), we hypothesized that continuous abdominal near-infrared spectroscopy (A-NIRS) measurement of splanchnic tissue oxygen saturation and intermittent plasma intestinal fatty-acid binding protein (pI-FABP) measured every 6 hours can detect NEC prior to onset of clinical symptoms. Premature piglets received parenteral nutrition for 48-hours after delivery, followed by enteral feeds every three hours until death or euthanasia at 96-hours. Continuous A-NIRS, systemic oxygen saturation (SpO2), and heart rate were measured while monitoring for clinical signs of NEC. Blood samples obtained at 6-hour intervals were used to determine pI-FABP levels by ELISA. Piglets were classified as fulminant-NEC (f-NEC), non-fulminant-NEC (nf-NEC) and No-NEC according to severity of clinical and histologic features. Of 38 piglets, 37% (n=14) developed nf-NEC, 18% (n=7) developed f-NEC and 45% (n=17) had No-NEC. There were significant differences in baseline heart rate (p=0.008), SpO2 (p<0.001) and A-NIRS (p<0.001) among the three groups. A-NIRS values of NEC piglets remained lower throughout the study with mean for f-NEC of 69±3.8%, 71.9±4.04% for nf-NEC, and 78.4±1.8% for No-NEC piglets (p<0.001). A-NIRS <75% predicted NEC with 97% sensitivity and 97% specificity. NEC piglets demonstrated greater variability from baseline in A-NIRS than healthy piglets (10.1% vs. 6.3%; p=0.04). Mean pI-FABP levels were higher in animals that developed NEC compared to No-NEC piglets (0.66 vs. 0.09 ng/mL;p<0.001). In f-NEC piglets, pI-FABP increased precipitously after feeds (0.04 to 1.87 ng/mL;p<0.001). pI-FABP levels increased in parallel with disease progression and a value >0.25ng/mL identified animals with NEC (68% sensitivity and 90% specificity). NIRS is a real-time, non-invasive tool that can serve as a diagnostic modality for NEC. In premature piglets, low A-NIRS in the early neonatal period and increased variability during initial feeds are highly predictive of NEC, which is then confirmed by rising plasma I-FABP levels. These modalities may help identify neonates with NEC prior to clinical manifestations of disease.

Effects of sodium bicarbonate correction of metabolic acidosis on regional tissue oxygenation in very low birth weight neonates.

To determine the effects of sodium bicarbonate (NaHCO3) correction of metabolic acidosis on cardiopulmonary, laboratory, and cerebral, renal and splanchnic regional oxygen saturation (rSO2) and fractional tissue oxygen extraction (FTOE) in extremely premature neonates during the first postnatal week. Observational cohort data were collected from 500 to 1250 g neonates who received NaHCO3 'half' corrections (0.3 * Weight (kg) * Base Deficit (mmol l(-1))) for presumed renal losses. Twelve subjects with normal blood pressure and heart rate received 17 NaHCO3 corrections. Mean (±s.d.) gestational age was 27±2 week and birth weight was 912±157 g. NaHCO3 corrections provided a mean (±s.d.) 4.5±1.0 ml kg(-1) fluid bolus, shifted mean (±s.d.) base deficit from 7.6±1.8 to 3.4±2.1 mmol l(-1) (P<0.05), and increased median (±s.d.) pH from 7.23±0.06 to 7.31±0.05 (P<0.05). No significant changes in blood pressure, pulse oximetry, PCO2, lactate, sodium, blood urea nitrogen, creatinine or hematocrit were observed. Cerebral, renal and splanchnic rSO2 (74%, 66% and 44%, respectively, at baseline) and FTOE (0.21, 0.29 and 0.52, respectively, at baseline) were unchanged following NaHCO3 correction. NaHCO3 infusions decreased base deficits and increased pH though produced no discernible effects or benefits on cardiopulmonary parameters including rSO2 and FTOE. These findings warrant further prospective evaluation in larger populations with more significant metabolic acidosis to determine the utility of tissue oxygenation monitoring in differentiating metabolic acidosis due to oxygen delivery/consumption imbalance versus renal bicarbonate losses.

Abdominal near-infrared spectroscopy in preterm infants: A comparison of splanchnic oxygen saturation measurements at two abdominal locations

BackgroundSplanchnic tissue oxygenation monitoring has been performed at both the liver and the infra-umbilical regions. It is unknown whether these measurements could be substituted one for the other when interpreting splanchnic oxygenation since they have not been measured simultaneously before. AimsTo evaluate the feasibility and safety of liver and infra-umbilical near-infrared spectroscopy (NIRS) monitoring in preterm infants with suspected necrotizing enterocolitis (NEC) and to assess the correlation and agreement between NIRS measurements performed simultaneously at the two abdominal locations. Study design and subjectsThis study was part of a prospective observational cohort study. Preterm infants who were suspected of NEC or who had been diagnosed with NEC were included. Outcome measuresLiver oxygen saturation and infra-umbilical oxygen saturation were monitored simultaneously and continuously for 48h by NIRS. ResultsNIRS monitoring was performed in 20 out of 24 infants for the entire 48-hour study period. No adverse effects were observed. Values of liver and infra-umbilical oxygen saturation correlated weakly (Spearman's rho=0.244, P<.001). On the Bland–Altman plot liver oxygen saturation was higher than infra-umbilical oxygen saturation (mean difference 6.6%, SD 22.5%). ConclusionsUsing NIRS as method for monitoring oxygen saturation simultaneously in both the liver and infra-umbilical regions is safe and feasible. Additionally, we demonstrated that values of liver and infra-umbilical oxygen saturation cannot be randomly substituted one for the other for the purpose of assessing splanchnic oxygenation.

Splanchnic Oxygen Saturation Immediately After Weaning From Cardiopulmonary Bypass Can Predict Early Postoperative Outcomes in Children Undergoing Congenital Heart Surgery

This study compared the abilities of cerebral, renal, and splanchnic regional oxygen saturation (rSO2) immediately after weaning from cardiopulmonary bypass (CPB) to predict early postoperative outcomes for children undergoing congenital heart surgery. The study enrolled 73 children (ages 0.1-72 months) undergoing corrective or palliative cardiac surgery requiring CPB. Laboratory and hemodynamic variables were analyzed at the time of successful weaning from CPB. Using near-infrared spectroscopy, cerebral, renal, and splanchnic rSO2 values were obtained simultaneously. Early postoperative outcome measures included the maximum vasoactive inotropic score (VIS(max)) during the first 36 postoperative hours, the duration of mechanical ventilation, and the postoperative hospital length of stay. In the univariate analysis, cerebral, renal, and splanchnic rSO2 values correlated significantly with early postoperative outcomes. However, splanchnic rSO2 was the only independent factor predicting VIS(max) (β = -0.302, P = 0.021), duration of mechanical ventilation (β = -0.390, P = 0.002), and postoperative hospital length of stay (β = -0.340, P = 0.001) by multivariate analyses. Splanchnic rSO2 had a larger receiver operating characteristic area under the curve (AUC) for determining high VIS(max), prolonged mechanical ventilation, and longer postoperative hospital stay (AUC 0.775, 0.792, and 0.776, respectively) than cerebral (AUC 0.630, 0.638, and 0.632, respectively) and renal (AUC 0.703, 0.716, and 0.715, respectively) rSO2. After weaning from CPB, splanchnic rSO2 may be superior to rSO2 measured from brain and kidney in predicting an increased requirement for vasoactive inotropic support, a prolonged mechanical ventilation, and a longer postoperative hospital stay for children.

Cerebral, Renal, and Splanchnic Tissue Oxygen Saturation Values in Healthy Term Newborns

To determine cerebral regional tissue oxygen saturation (CrSO2), renal regional tissue oxygen saturation (RrSO2), and splanchnic regional tissue oxygen saturation (SrSO2) values in healthy term infants. Near-infrared spectroscopy was used to simultaneously measure CrSO2, RrSO2, and SrSO2 continuously for a 1-hour period on the first and second days of life. A total of 41 subjects were monitored out of which complete data were available for 38 subjects. Mean CrSO2 was 78.2 ± 7.9% on first day; 78.3 ± 6.1% on second day (p = 0.95). Mean RrSO2 was 92.1 ± 5.3% on first day; 88.9 ± 5.9% on second day (p < 0.01). Mean SrSO2 was 69.9 ± 12.1% on first day and 75.3 ± 12.4% on second day (p = 0.02). There appears to be consistency in rSO2 values in healthy newborns. CrSO2 was similar on both days. Differences observed in RrSO2 and SrSO2 between days may represent a shift in somatic blood flow distribution taking place during the first day of life.

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.

Investigation of photoplethysmographic signals and blood oxygen saturation values obtained from human splanchnic organs using a fiber optic sensor

A reliable, continuous method of monitoring splanchnic organ oxygen saturation could allow for the early detection of malperfusion, and may prevent the onset of multiple organ failure. Current monitoring techniques have not been widely accepted in critical care monitoring. As a preliminary to developing a continuous indwelling device, this study evaluates a new handheld fiber optic photoplethysmographic (PPG) sensor for estimating the blood oxygen saturation (SpO(2)) of splanchnic organs during surgery. A fiber optic splanchnic PPG sensor, instrumentation system and virtual instrument were developed to facilitate PPG and SpO(2) measurement from splanchnic organs. Following Local Research Ethics Committee approval, the sensor was evaluated on seventeen ASA 1 and 2 patients undergoing open laparotomy. PPG signals were obtained from the large bowel, small bowel, liver and stomach. Simultaneous PPG signals from the finger were also obtained using an identical fiber optic sensor. Good quality PPG signals with high signal-to-noise (SNR) ratios were obtained from all splanchnic sites under investigation. Analysis of the ac and dc amplitudes of the red and infrared PPG signals showed there to be a statistically significant difference between PPG signals obtained from splanchnic organs with those obtained from the finger (using fiber optic sensors). Estimated SpO(2) values from the splanchnic organs show good agreement with those obtained from the finger using both a fiber optic sensor and a commercial device. Furthermore, the results of a Bland and Altman analysis indicate that fiber optic splanchnic pulse oximetry, particularly of the bowel, may provide a suitable method for monitoring splanchnic organ perfusion. The evaluation of a new fiber optic sensor on anaesthetized patients undergoing laparotomy demonstrated that good quality PPG signals and SpO(2) estimates can be obtained from splanchnic organs. Such a sensor may provide a useful tool for the intraoperative assessment of splanchnic perfusion.

A new fibre optic pulse oximeter probe for monitoring splanchnic organ arterial blood oxygen saturation

A new, continuous method of monitoring splanchnic organ oxygen saturation (SpO2) would make the early detection of inadequate tissue oxygenation feasible, reducing the risk of hypoperfusion, severe ischaemia, and, ultimately, death. In an attempt to provide such a device, a new fibre optic based reflectance pulse oximeter probe and processing system were developed followed by an in vivo evaluation of the technology on seventeen patients undergoing elective laparotomy. Photoplethysmographic (PPG) signals of good quality and high signal-to-noise ratio were obtained from the small bowel, large bowel, liver and stomach. Simultaneous peripheral PPG signals from the finger were also obtained for comparison purposes. Analysis of the amplitudes of all acquired PPG signals indicated much larger amplitudes for those signals obtained from splanchnic organs than those obtained from the finger. Estimated SpO2 values for splanchnic organs showed good agreement with those obtained from the finger fibre optic probe and those obtained from a commercial device. These preliminary results suggest that a miniaturized ‘indwelling’ fibre optic sensor may be a suitable method for pre-operative and post-operative evaluation of splanchnic organ SpO2 and their health.