Mirjam Pocivalnik

Regional Oxygen Saturation of the Brain and Peripheral Tissue during Birth Transition of Term Infants

OBJECTIVE To evaluate regional tissue oxygenation of the brain and preductal and postductal peripheral (muscle) tissue during immediate transition after birth, and to correlate with peripheral preductal and postductal arterial oxygen saturation. STUDY DESIGN We conducted a prospective observational study. With near-infrared spectroscopy (NIRS), changes in regional oxygen saturation of the brain (rSO2brain), peripheral preductal tissue (rSO2pre), and peripheral postductal tissue (rSO2post) were measured during the first 10 minutes of life in 59 healthy term infants after elective caesarean delivery. Fractional tissue oxygen extraction was calculated for all 3 regions. RESULTS Mean rSO2brain increased rapidly from 44% (3 minutes) to 76% (7 minutes); thereafter no significant change occurred. Mean rSO2pre and rSO2post increased constantly from minute 3 to minute 10, from 36%(pre)/27%(post) to 66%(pre)/58%(post). Fractional tissue oxygen extraction decreased in all 3 regions during the first minutes of life. Fractional tissue oxygen extraction of the brain did not change significantly after 5 minutes, and preductal and postductal fractional tissue oxygen extraction did not change significantly after 8 minutes. CONCLUSIONS During transition, the brain had the highest saturation levels, indicating a preference of oxygen delivery to the brain. Fractional tissue oxygen extraction of the brain reached a plateau earlier compared with peripheral tissue.

Cerebral and Peripheral Regional Oxygen Saturation during Postnatal Transition in Preterm Neonates

OBJECTIVE To evaluate peripheral regional oxygen saturation (rpSO₂) and cerebral regional oxygen saturation (rcSO₂) during the immediate postnatal transition in late preterm infants with and without the need for respiratory support. STUDY DESIGN This was a prospective observational study using near-infrared spectroscopy to evaluate changes in rpSO₂ and rcSO₂. These variables were measured during the first 15 minutes of life after elective cesarean delivery. Peripheral oxygen saturation (SpO₂) and heart rate were measured continuously by pulse oximetry, and cerebral fractional tissue oxygen extraction (cFTOE) was calculated. Two groups were compared based on their need for respiratory support: a respiratory support group and a normal transition group. Positive-pressure ventilation was delivered with a T-piece resuscitator, and oxygen was adjusted based on SpO₂ values. A Florian respiratory function monitor was used to record the ventilation variables. RESULTS There were 21 infants in the normal transition group and 21 infants in the respiratory support group. Changes in heart rate over time were similar in the 2 groups. SpO₂, rcSO₂, and rpSO₂ values were consistently higher in the normal transition group. In the respiratory support group, cFTOE values remained significantly elevated for a longer period. CONCLUSION This systematic analysis of rpSO₂, rcSO₂, and cFTOE in late preterm infants found significantly lower oxygen saturation values in infants who received respiratory support compared with a normal transition group. We hypothesize that the elevated cFTOE values in the respiratory support group represent compensation for lower oxygen delivery.

Regional cerebral oxygen saturation in newborn infants in the first 15 min of life after vaginal delivery

The objective of this study was to evaluate regional oxygen saturation of the brain during immediate transition after birth, and to correlate it with pre-ductal arterial oxygen saturation in newborn infants. The prospective observational study including newborn infants in the first 15 min after spontaneous vaginal delivery and uncomplicated transitional period was undertaken. Regional cerebral oxygen saturation (rSO(2)brain) was measured using near-infrared spectroscopy. Arterial oxygen saturation (SpO(2)) and heart rate (HR) were measured on the right wrist by pulse oximetry. rSO(2)brain, SpO(2) and HR measurements were started immediately after birth and were performed in the first 15 min of life. Cerebral fractional tissue oxygen extraction (FTOE) was calculated for each minute. Of 145 newborn infants, 16 were included and the gender allocation was 31 females (49.2%) and 32 males (50.8%). rSO(2)brain increased rapidly from 39% (2 min) to 69% (5 min), SpO(2) increased from 72% (2 min) to 96% (14 min) and FTOE showed a significant decrease from minute 2 (0.47) until minute 4 (0.30) and an increase between 8 to 13 min. rSO(2)brain increased rapidly after vaginal delivery. Although SpO(2) increased within the first 14 min after delivery, rSO(2)brain showed no further significant changes after 5 min. FTOE decreased in the first 4 min and reached standard values subsequently.

A Left-to-Right Shunt via the Ductus Arteriosus Is Associated with Increased Regional Cerebral Oxygen Saturation during Neonatal Transition

Background: Oxygen delivery to the brain is dependent on cardiac output and arterial oxygen content. Objectives: The study was designed to investigate the influence of a left-to-right shunt via the ductus arteriosus (DA) on regional oxygen saturation (rSO2) of the brain and peripheral tissue during postnatal transition. Methods: Nested case-control study. In term neonates after elective cesarian section, rSO2 of the brain and pre- and postductal peripheral tissue were measured 15 min after uncomplicated postnatal transition. Two groups were formed according to shunt flow characteristics via the DA: shunt group (with a left-to-right shunt), and nonshunt group (no shunt). Results: Of 80 infants, in 58 (72%) a left-to-right shunt was identified, and in 22 (28%) no flow was seen via the DA. The 22 infants formed the nonshunt group. They were matched with 22 newborn infants with a left-to-right shunt via the DA (shunt group). Infants in the nonshunt group had significantly lower cerebral rSO2 values and higher fractional tissue oxygen extraction and heart rate values. There were no significant differences in regard to peripheral rSO2 values. Conclusion: During postnatal transition, term infants with a left-to-right shunt via the DA have significantly higher cerebral rSO2 values compared to infants without shunt flow.

C reactive protein: impact on peripheral tissue oxygenation and perfusion in neonates

Objective C reactive protein (CRP) is a sensitive marker of acute inflammation of infectious and non-infectious origin. Aim was to use near-infrared spectroscopy (NIRS) to analyse peripheral oxygenation and perfusion in term and preterm neonates with elevated CRP levels, at a time when routine haemodynamic variables are still normal. Design Prospective observational study. Settings Peripheral-muscle NIRS was performed in the first week of life. Tissue-oxygenation index (TOI), mixed venous oxygenation (SvO2), fractional oxygen extraction (FOE), haemoglobin flow (Hbflow), oxygen delivery (DO2) and oxygen consumption (VO2) were assessed. Blood samples were taken within 3 h of the NIRS measurements. Patients Cardiocirculatory stable term and preterm neonates with infection-related and infection-unrelated CRP elevations >10 mg/l were compared with neonates without CRP elevation. The two groups were matched for gestational and postnatal age. Results 33 neonates with CRP elevation (gestational age 37.7±2.9 weeks) were compared with 33 controls (gestational age 37.3±2.9 weeks). In neonates with CRP elevation, TOI (68.9±6.6%), SvO2 (66.9±7.3%) DO2 (39.2±16.1 µmol/100ml/min) and VO2 (10.9±3.4 µmol/100ml/min) were significantly lower compared with controls (TOI 72.9±3.8%, SvO2 70.2±4.7%, DO2 48.8±18.4 µmol/100ml/min, VO2 12.3±3.8 µmol/100ml/min). There was no significant difference in any other NIRS or routine haemodynamic parameter between the two groups. Conclusion Inflammatory processes with CRP elevation cause impaired peripheral oxygenation and perfusion in neonates even when routine haemodynamic variables are still normal. NIRS might offer a new non-invasive tool for the early recognition and diagnosis of infectious and non-infectious inflammatory processes.

The influence of perinatal asphyxia on peripheral oxygenation and perfusion in neonates

BACKGROUND Perinatal asphyxia influences peripheral oxygenation and perfusion in neonates. OBJECTIVES The aim was to investigate the influence of perinatal asphyxia on peripheral oxygenation and perfusion in neonates by using near-infrared spectroscopy (NIRS). METHODS Prospective observational study. Neonates with gestational age >34 weeks and birth weight >2000 g without infection or congenital malformations were included. Peripheral muscle NIRS measurements in combination with venous occlusion were performed once in the first 48 h of life. Tissue oxygenation index (TOI), mixed venous oxygenation (SvO2), fractional oxygen extraction (FOE), haemoglobin flow (Hbflow), oxygen delivery (DO2) and oxygen consumption (VO2) were assessed. Furthermore arterial oxygen saturation, heart rate, blood pressure and temperatures were measured. Neonates with a UapH≤7.15 and an Apgar 5≤6 were compared to neonates with a UapH≥7.15, an Apgar 5≥7 (control group) and a UapH was correlated to NIRS parameters. RESULTS 8 asphyxiated neonates were compared to 30 neonates in the control group. TOI (67.7±5.5%) and DO2 (29.0±14.2 μmol/100 mL/min) were significantly lower in asphyxiated neonates compared to the controls (TOI 71.8±4.9%, p=0.045; DO2 43.9±16.9 μmol/100 mL/min, p=0.028) and FOE was significantly higher (0.33±0.05) compared to the controls (0.28±0.06, p=0.028). Furthermore significant correlations between UapH and DO2 (r=0.78, p=0.022), VO2 (r=0.80, p=0.018) and FOE (r=-0.75, p=0.034) in the asphyxiated group were found. CONCLUSION Peripheral oxygenation and perfusion measured with NIRS are compromised in neonates with perinatal asphyxia with worsening of parameters and degree of acidosis in the umbilical cord blood.

Cerebral regional oxygen saturation (crSO2): are different sensors comparable?

Background:  For measurement of cerebral regional oxygen saturation (crSO2) in neonates, one of the frequently used near‐infrared spectroscopy devices is the INVOS 5100 with either the neonatal or pediatric sensor. Measurements between adult and pediatric sensors use different algorithms and differ by 10%. There are no published data comparing neonatal and pediatric sensors.

‘Multi-associations’: predisposed to misinterpretation of peripheral tissue oxygenation and circulation in neonates

Interpretation of peripheral circulation in ill neonates is crucial but difficult. The aim was to analyse parameters potentially influencing peripheral oxygenation and circulation. In a prospective observational cohort study in 116 cardio-circulatory stable neonates, peripheral muscle near-infrared spectroscopy (NIRS) with venous occlusion was performed. Tissue oxygenation index (TOI), mixed venous oxygenation (SvO(2)), fractional oxygen extraction (FOE), fractional tissue oxygen extraction (FTOE), haemoglobin flow (Hbflow), oxygen delivery (DO(2)), oxygen consumption (VO(2)), and vascular resistance (VR) were assessed. Correlation coefficients between NIRS parameters and demographic parameters (gestational age, birth weight, age, actual weight, diameter of calf, subcutaneous adipose tissue), monitoring parameters (heart rate, arterial oxygen saturation (SaO(2)), mean blood pressure (MAP), core/peripheral temperature, central/peripheral capillary refill time) and laboratory parameters (haemoglobin concentration (Hb-blood), pCO(2)) were calculated. All demographic parameters except for Hbflow and DO(2) correlated with NIRS parameters. Heart rate correlated with TOI, SvO(2), VO(2) and VR. SaO(2) correlated with FOE/FTOE. MAP correlated with Hbflow, DO(2), VO(2) and VR. Core temperature correlated with FTOE. Peripheral temperature correlated with all NIRS parameters except VO(2). Hb-blood correlated with FOE and VR. pCO(2) levels correlated with TOI and SvO(2). The presence of multiple interdependent factors associated with peripheral oxygenation and circulation highlights the difficulty in interpreting NIRS data. Nevertheless, these findings have to be taken into account when analysing peripheral oxygenation and circulation data.

Tilting the Head Changes Cerebral Haemodynamics in Neonates

Background: Tilting only the head influences cerebral haemodynamics in term and preterm neonates. Objective: To evaluate near-infrared spectroscopy (NIRS) as a method to detect changes of cerebral oxygenated (HbO2) and deoxygenated haemoglobin (Hb) and ‘cerebral tissue-oxygenation-index’ (cTOI) while tilting. Furthermore to investigate whether the comparison of cTOI and ‘cerebral mixed venous oxygen saturation’ (tiltSvO2), calculated out of the increase of HbO2 and Hb, improves reproducibility. Methods: During five ‘reapplication’ periods of NIRS optodes on the left forehead of 40 neonates, five tilting manoeuvres of the head were performed. Changes of NIRS parameters during tilting were analysed. The first quality criterion was defined by a linear increase of total haemoglobin (HbT; r2 > 0.95). The second quality criterion was: cTOI > tiltSvO2 (= cTOI – tiltSvO2> 0). Analysis of variance components and comparison of mean of standard deviations were applied to data after introduction of each quality criterion. Results: While HbO2, Hb and HbT showed a linear increase in all neonates during tilting, cTOI did not change. With the introduction of the second criterion, mean cTOI increased from 73.7 ± 6.9 to 75.1 ± 6.9%, mean tiltSvO2 decreased from 72.6 ± 7.1 to 65.3 ± 6.9% and mean of standard deviations of both parameters decreased. The analysis of variance components showed no significant change. Conclusion: A tilting-down manoeuvre of the head of term and preterm neonates can cause an increase of HbO2, Hb and HbT. tiltSvO2 can be calculated out of these changes. By introducing two quality criteria, reproducibility of cerebral NIRS measurements (cTOI and tiltSvO2) improved.

Causes of hematochezia and hemorrhagic antibiotic-associated colitis in children and adolescents.

Abstract Diseases causing hematochezia range from benign to potentially life-threatening. Systematic pediatric data on the causes of hematochezia are scarce. We studied the underlying causes and long-term outcome of hematochezia in children. We further investigated the relevance of antibiotic-associated hemorrhagic colitis in children, especially if caused by Klebsiella oxytoca. Infants, children, and adolescents with hematochezia were recruited prospectively. Patients were grouped according to age (<1 year, 1–5 years, 6–13 years, >14 years). In addition to routine diagnostics, K oxytoca stool culture and toxin analysis was performed. We collected data on history, laboratory findings, microbiological diagnostic, imaging, final diagnosis, and long-term outcome. We included 221 patients (female 46%; age 0–19 years). In 98 (44%), hematochezia was caused by infectious diseases. Endoscopy was performed in 30 patients (13.6%). No patient died due to the underlying cause of hematochezia. The most common diagnoses according to age were food protein-induced proctocolitis in infants, bacterial colitis in young children, and inflammatory bowel disease in children and adolescents. Seventeen (7.7%) had a positive stool culture for K oxytoca. Antibiotic-associated colitis was diagnosed in 12 (5%) patients: 2 caused by K oxytoca and 2 by Clostridium difficile; in the remaining 8 patients, no known pathobiont was identified. Infections were the most common cause of hematochezia in this study. In most patients, invasive diagnostic procedures were not necessary. Antibiotic-associated hemorrhagic colitis caused by K oxytoca was an uncommon diagnosis in our cohort. Antibiotic-associated colitis with hematochezia might be caused by pathobionts other than C difficile or K oxytoca.