End-tidal Carbon Monoxide Research Articles

Bilirubin production and hour-specific bilirubin levels.

We assessed the relative contributions of increased bilirubin production (indexed by end-tidal carbon monoxide (CO) concentrations, corrected for ambient CO (ETCOc)) to hour-specific total bilirubin (TB) levels in healthy late preterm and term newborns. Post hoc analyses of concurrent ETCOc and TB (at 30±6 h of age) and follow-up TB levels at age 96±12 h and up to 168 h after birth were performed in a cohort of 641 term and late preterm infants. Increased bilirubin production (hour-specific ETCOc ⩾1.7 p.p.m. at age 30±6 h) was noted in ~80%, 42% and 32% of infants in the high-, intermediate- and low-risk TB zones, respectively. One infant with TB <40th percentile and ETCOc <1.7 p.p.m. developed TB ⩾95th percentile at age 168 h, probably due to decreased bilirubin elimination. Infants in the high-risk quartile of the hour-specific bilirubin nomogram have a higher mean bilirubin production. Infants with TB levels ⩾95th percentile without increased bilirubin production have impaired bilirubin elimination.

Monitoring recovery from iron deficiency using total hemoglobin mass.

Using hemoglobin concentration ([Hb]) to diagnose borderline iron deficiency and monitor the progress of its treatment is difficult because of the confounding effects of plasma volume. Because hemoglobin mass (Hbmass) is not affected by plasma volume, it may be a more sensitive parameter. The aim of this study was to monitor Hbmass, iron storage, and maximal oxygen consumption (V˙O2max) during and after oral iron therapy in subjects with severe and moderate iron deficiency. Three groups of female recreational athletes were monitored for at least 22 wk, as follows: 1) severe iron deficiency group (SID) (n = 8; ferritin, ≤12 ng·mL), 2) moderate iron deficiency group (MID) (n = 14; ferritin, ≤25 ng·mL), and 3) control group (n = 8; ferritin, >25 ng·mL). Hbmass and iron status were determined before, during, and up to 12 wk after at least 10 wk of oral iron supplementation. In total, five V˙O2max tests were performed before, during, and after the supplementation period. Hbmass increased markedly in the SID group (15.6% ± 11.0%, P < 0.001) and slightly in the MID group (2.2% ± 3.7%, P < 0.05) by the end of the supplementation period and remained at this level for the following 12 wk. [Hb] and Hbmass were similarly affected, but Hbmass was more closely related to mean corpuscular volume and mean corpuscular hemoglobin than [Hb]. The SID group incorporated 534 ± 127 mg of iron into ferritin and hemoglobin, whereas the MID group incorporated 282 ± 68 mg of iron. V˙O2max increased only in the SID group by 0.20 ± 0.18 L·min (P < 0.05) and was closely related to Hbmass (P < 0.01). Hbmass is a sensitive tool for monitoring recovery from iron deficiency anemia and assessing the effectiveness of iron supplementation in individuals with severe or moderate iron deficiency.

Elevated End-Tidal Carbon Monoxide Concentration in Children with Sickle Cell Anemia

Background: Carbon monoxide (CO) produced during oxygen-dependent cleavage of porphyrin ring of heme is excreted in exhaled breath. The catabolism of heme is increased when red blood cells are destroyed at an accelerated rate. Thus, quantifying CO in exhaled breath could serve as an indicator of hemolysis. However, the requirement for forced breath sample has limited the measurement of exhaled CO in young children.Objective: To assess end-tidal CO concentration (ETCOc) in children with sickle cell anemia (SCA).Design/Methods: ETCOc was measured using the CoSense ETCO Monitor (Capnia Inc. Palo Alto, CA). Children between 5-14 years with SCA (Hb SS) who were not on chronic transfusions were eligible. Healthy children served as age-matched controls. Children with exposure to second-hand smoke, acute respiratory infection or symptomatic asthma were excluded. End-tidal breath samples were collected by placing the tip of a nasal cannula 5 mm into the nares. Up to 3 measurements were taken for each subject and the highest ETCOc value was used for analysis. (ClinicalTrials.gov: NCT01848691)Results: The mean (range) age of 16 children with SCA and 16 controls was 9.7 years (5-14 years) and 9.9 years (5-14 years), respectively. The mean (± s.d.) ETCOc for SCA was 4.85 ± 2.24 ppm versus 0.96 ± 0.54 ppm for control group (p<0.001). The ETCOc in the control group ranged from 0.2 to 2.3 ppm, but was ≤1.2 ppm in 14/16, which is suggested as the upper limit of normal for healthy children. In the SCA group, the ETCOc range was 1.8 to 9.7 ppm, with values ≥2.4 ppm in 15/16 subjects. A threshold ETCOc value of >2.1 ppm provided both sensitivity and specificity equal to 93.8% (69.8-99.8%) for distinguishing SCA from healthy children. Children with SCA who had higher absolute reticulocyte count also demonstrated higher ETCOc (r=0.62, p=0.011). Patients with severe anemia (hemoglobin <8 g/dL) had a higher mean ETCOc (5.43 ppm) than the rest (4.40 ppm) but the difference was not significant. ETCOc level tended to increase with age in SCA (r=0.45, p=0.08).Conclusions: Carbon monoxide in exhaled breath can be measured in young children in the clinic using a portable monitor. ETCOc may be a valuable tool for non-invasive monitoring of the severity of hemolysis in SCA. The mean ETCOc was 5-fold higher in SCA compared with controls, with little overlap seen between the groups. This suggests a potential use for ETCOc as a point-of-care screening test for SCA in children. [Display omitted] [Display omitted] DisclosuresLal:Capnia, Inc: Research Funding. Yen:Capnia, Inc. : Employment. Bhatnagar:Capnia, Inc: Employment.

End-tidal carbon monoxide as an indicator of the hemolytic rate.

In the first days of life, low grade jaundice is essentially universal. The source of the elevated bilirubin level giving rise to "physiological jaundice of the newborn" is only partly known. We hypothesized that it is, at least in part, the result of active and specific hemolysis involving a physiological mechanism to lower the high fetal hematocrit, appropriate for the relatively low oxygen environment in utero, to a lower level appropriate for the state of oxygen abundance after birth. We tested this by quantifying end tidal carbon monoxide (ETCO) as a marker of the rate of heme metabolism to bilirubin. We found that ETCO values of 20 neonates and children with known hemolytic disorders were higher than 20 age-matched healthy controls (p<0.0001), indicating that this instrumentation recognizes hemolysis in neonates and children. We also found that ETCO reference intervals were indeed higher in healthy neonates during the first three days after birth (5th to 95th percentile reference range, 1.4 to 1.7ppm) than after 1month of age (all ≤1.0ppm, p<0.0001). These results suggest to us that hemolysis is physiological during the first days after birth. The cellular and molecular mechanisms responsible for transient hemolysis after birth are topics of current investigation.

End-tidal carbon monoxide and hemolysis.

Hemolytic disease in newborns can result from a number of conditions, which can place such infants at an increased risk for the development of severe hyperbilirubinemia. Because the catabolism of heme produces equimolar amounts of carbon monoxide (CO) and bilirubin, measurements of end-tidal breath CO (corrected for ambient CO) or ETCOc can serve as an index of hemolysis as well as of bilirubin production from any cause. Elevated levels of ETCOc have been correlated with blood carboxyhemoglobin levels and thus hemolysis. However, the detection of hemolysis can be a clinically challenging problem in newborns. Here, we describe the importance of determining ETCOc levels and their application in identifying infants at risk for developing hyperbilirubinemia associated with hemolysis and other causes of increased bilirubin production.

Unmyelinated White Matter Loss in the Preterm Brain Is Associated with Early Increased Levels of End-Tidal Carbon Monoxide

ObjectiveIncreased levels of end-tidal carbon monoxide (ETCOc) in preterm infants during the first day of life are associated with oxidative stress, inflammatory processes and adverse neurodevelopmental outcome at 2 years of age. Therefore, we hypothesized that early ETCOc levels may also be associated with impaired growth of unmyelinated cerebral white matter.MethodsFrom a cohort of 156 extremely and very preterm infants in which ETCOc was determined within 24 h after birth, in 36 infants 3D-MRI was performed at term-equivalent age to assess cerebral tissue volumes of important brain regions.ResultsLinear regression analysis between cerebral ventricular volume, unmyelinated white matter/total brain volume-, and cortical grey matter/total brain volume-ratio and ETCOc showed a positive, negative and positive correlation, respectively. Multivariable analyses showed that solely ETCOc was positively related to cerebral ventricular volume and cortical grey matter/total brain volume ratio, and that solely ETCOc was inversely related to the unmyelinated white matter/total brain volume ratio, suggesting that increased levels of ETCOc, associated with oxidative stress and inflammation, were related with impaired growth of unmyelinated white matter.ConclusionIncreased values of ETCOc, measured within the first 24 hours of life may be indicative of oxidative stress and inflammation in the immediate perinatal period, resulting in impaired growth of the vulnerable unmyelinated white matter of the preterm brain.

Comparison of end tidal carbon monoxide (eCO) levels in shisha (water pipe) and cigarette smokers

BackgroundMeasuring eCo is rapid, non-invasive and inexpensive tool and correlate correctly with carboxyhemoglobin levels in blood. The aim of this study was to evaluate and compare the increase in end tidal carbon monoxide (eCO) levels in exhaled breath of passive smokers and healthy smokers after cigarette and shisha smoking.FindingsIn a cross sectional study eCO levels were measured in 70 subjects (24 cigarette smokers, 20 shisha smoker, 26 passive smokers) by use of portable device. Smokers were asked to smoke shisha for 30 mins in shisha cafe or to smoke 5 cigarettes in 30 mins in a restaurant. eCo levels were measured at baseline (30 mins), 35 mins, 60 mins and 90 mins in all groups after entry to the venue. The baseline mean eCO level among cigarette smokers was 3.5 +/- 0.6 ppm (part per million), passive cigarette smokers 3.7+/-1.0 ppm, shisha smokers 27.7+/-4.9 ppm and passive shisha smokers 18.3+/-8.4 ppm .The mean increase in eCO after 90 min among smokers was 9.4+/-4.6 (p < 0.005), passive cigarette smokers 3.5+/-2.5 (p < 0.05), shisha smokers 57.9+/-27.4 (p <0.005) and passive shisha smokers 13.3+/-4.6 (p = 0.03).ConclusionExposure to shisha smoke is a cause of elevated eCO in smokers and passive smokers and due to in-door pollution, sitting in shisha bar causes significant increase in eCO levels.

Early End-Tidal Carbon Monoxide Levels, Patency of the Ductus Arteriosus and Regional Cerebral Oxygenation in Preterm Infants

Background: Carbon monoxide (CO), a relaxant regulator of muscle tone and marker of oxidative stress and inflammation, can be measured in exhaled air by determination of end-tidal CO corrected for CO in ambient air (ETCOc). Objective: Increased endogenous production of CO may influence patency of the ductus arteriosus, cerebral perfusion and, subsequently, cerebral oxygenation. The aim was to study the relation between early ETCOc levels, hemodynamically significant patent ductus arteriosus (hsPDA) and cerebral oxygenation (rScO₂) in preterm infants <32 weeks' gestational age and determine predictive values of ETCOc for hsPDA. Methods: ETCOc was measured in 91 infants within the first 24 h after birth. A hsPDA was diagnosed according to echocardiographic indices. In 78/91 infants, rScO₂ was monitored with near-infrared spectroscopy to assess cerebral oxygenation. Results: ETCOc values were significantly higher in infants who subsequently developed hsPDA (2.3 ± 0.7 ppm) vs. no-hsPDA (1.7 ± 0.6 ppm), p < 0.001. With a cut-off value of 2.5 ppm, positive and negative predictive values of ETCOc for hsPDA were 55 and 88%, respectively. rScO₂ values were not different between the two groups (64 ± 1 vs. 65 ± 3%, NS). Conclusions: The higher ETCOc values in hsPDA infants early after birth reflect the early relaxant state of ductal muscular tone. ETCOc <2.5 ppm within 24 h after birth may predict the subsequent absence of hsPDA. ETCOc showed no correlation with cerebral oxygenation in both groups.

Early biomarkers as predictors for bronchopulmonary dysplasia in preterm infants: a systematic review

Bronchopulmonary dysplasia (BPD) is usually diagnosed in preterm infants at least 28 days after birth. Great interest lies in the potential to identify biomarkers that predict development of the disease and future neurodevelopmental outcomes. We have reviewed the existing literature on early biomarkers as predictors for BPD in preterm infants. Two reviewers independently searched the databases of PubMed, EMBASE, and Google Scholar for studies pertaining to biomarkers for BPD. Studies were assessed using Quality Assessment of Diagnostic Accuracy Studies criteria. We identified 46 relevant articles that are summarized in the review. These studies assessed over 30 potential biomarkers. Sensitivity and specificity of biomarkers were reported or could be calculated for only 16 articles, and ranged from 0 to 100 %. Based on the nine highest quality studies, serum KL-6, CC16, neutrophil gelatinase-associated lipocalin, and end-tidal carbon monoxide (etCO) perform extremely well in predicting the early diagnosis of established BPD, highlighting these biomarkers as promising candidates for future research. Published data from studies on serum biomarkers and etCO suggest that biomarkers may have great potential to predict the subsequent BPD and neurodevelopmental outcomes. These biomarkers need validation in larger studies, and the generalizability of biomarkers for predicting BPD, as well as the neurodevelopmental outcomes, needs to be further explored.

Chronic carbon monoxide inhalation during pregnancy augments uterine artery blood flow and uteroplacental vascular growth in mice

End-tidal breath carbon monoxide (CO) is abnormally low in women with preeclampsia (PE), while women smoking during pregnancy have shown an increase in CO levels and a 33% lower incidence of PE. This effect may be, in part, due to lowered sFLT1 plasma levels in smokers, and perhaps low-level CO inhalation can attenuate the development of PE in high-risk women. Our previous work showed maternal chronic CO exposure (<300 ppm) throughout gestation had no maternal or fetal deleterious effects in mice. Our current study evaluated the uteroplacental vascular effects in CD-1 maternal mice that inhaled CO (250 ppm) both chronically, gestation day (GD) 0.5 to 18.5, and acutely, 2.5 h on each of GD 10.5 and 14.5. We demonstrated, using microultrasound measurements of blood velocity and microcomputed tomography imaging of the uteroplacental vasculature, that chronic maternal exposure to CO doubled uterine artery blood flow and augmented uteroplacental vascular diameters and branching. This finding may be of benefit to women with PE, as they exhibit uteroplacental vascular compromise. The ratio of VEGF protein to its FLT1 receptor was increased in the placenta, suggesting a shift to a more angiogenic state; however, maternal circulating levels of VEGF, sFLT1, and their ratio were not significantly changed. Doppler blood velocities in the maternal uterine artery and fetal umbilical artery and vein were unaltered. This study provides in vivo evidence that chronic inhalation of 250 ppm CO throughout gestation augments uterine blood flow and uteroplacental vascular growth, changes that may protect against the subsequent development of preeclampsia.

End-Tidal Breath Carbon Monoxide Measurements: Current Directions

Because heme catabolism leads to the formation of equimolar amounts of carbon monoxide (CO) and bilirubin, a variety of techniques have been developed to correlate CO production rates as indices of bilirubin production. The use of end-tidal breath CO measurements for estimating rates of bilirubin production in infants has been well documented and validated in a number of clinical studies for its use and predictive value in identifying infants who are high producers of bilirubin and hence at risk for developing pathologic neonatal hyperbilirubinemia. Recently, end-tidal breath CO has been suggested as a marker for chronic lung disease and developmental problems. Trace gas analysis remains an area for interesting investigation in the future.

Self-reported cigarette smoking status imprecisely quantifies exposure in pregnancy

Objective: We sought to determine the validity of self-reported smoking activity versus two quantitative measurements of tobacco exposure in pregnancy. We hypothesized that pregnant women would under-report their daily smoking amounts, due to the negative social stigmas associated with such a behavior. Methods: Cigarette-smoking and non-smoking pregnant women were recruited as part of a larger research study. Pregnant women with a singleton baby (>24 weeks) were recruited at a clinical appointment or prior to an elective caesarian section. Self-reported smoking status, including time since last cigarette, was recorded. End-tidal breath carbon monoxide (ETCO) levels and urine cotinine levels were measured and compared. Results: Both normotensive non-smoking (NTN) (n = 44) and normotensive smoking (NTS) (n = 24) pregnant women were recruited. A strong correlation was found between ETCO levels and urine cotinine measurements (r = 0.6566, p 0.05). Conclusion: Self-reported smoking status accurately identifies women who smoke in pregnancy, but not their level of tobacco exposure. Urine cotinine or ETCO are much better quantitative measurements of nicotine and carbon monoxide, respectively, and should be measured for a more precise indicator of smoking activity. These devices will allow for better counseling and monitoring of women who are trying to quit smoking and/or who enter into smoking cessation programs.

End-Tidal Carbon Monoxide and Regional Cerebral Oxygenation Saturation in Preterm Neonates with and Without a Patent Ductus Arteriosus

Background: Carbon monoxide (CO), an inflammatory marker, can be measured in exhaled air as end-tidal(et)CO. High levels of CO can induce vasodilatation and may alter cerebral perfusion/oxygenation. The inflammatory state can also influence the persistence of a patent ductus arteriosus (PDA). Cerebral oxygenation can be monitored by near-infrared spectrometry (NIRS). Aim: To study the predictive value of etCO measured within 24 hours after birth for a PDA as well as the relationship between etCOc and NIRS on the first day of life in preterm infants. Patients and Methods: 91 preterm neonates (< 32 weeks GA) admitted to the neonatal intensive care unit of the Wilhelmina children's hospital were included. EtCOc was measured within 24 hours after birth. 78 of the included infants were NIRS-monitored for regional cerebral oxygen saturation (rScO2) during the first day of life. PDA was diagnosed according to standard echocardiographic indices. Results: EtCOc measured within 24 hours after birth was significantly higher in preterm neonates who developed PDA (mean 2.34 PPM ± 0.71SD) compared to infants who did not develop PDA (mean 1.74 ± 0.63SD) (p< 0.001). Measuring etCOc within 24 hours after birth has a sensitivity of 60% and a specificity of 86% in predicting PDA. High values of etCOc are determined by a cut-off value of 2,4 PPM. No statistically significant correlation could be found between etCOc and NIRS-measured rScO2. Conclusion: High values of etCOc are related with PDA. EtCOc seems not to be related to rScO2 on the first day of life.

End-Tidal Carbon Monoxide (ETCOC) at Day One Predicts Unmyelinated White Matter (UNMWM) Volume at Term Equivalent Age of Very Preterm Neonates

Background: Increased levels of ETCOc in preterm infants during the1st day of life are associated with inflammatory processes, oxidative stress and adverse neurodevelopmental outcome at 2 years of life (Krediet et al, Acta Pediatr 2006) Objective: To investigate the relation between early ETCOc levels and unmyelinated white matter volume. Design/methods: From a cohort of 156 extremely and very preterm infants in which ETCOc was determined within 24 h after birth, 30 infants had volumetric MR imaging at term equivalent age for determination of different cerebral tissue classes. Results: Median [range] of GA, BW and ETCOc, were 26.4 [25.0-29.9] wk, 972 [680-1700] g and 2.2 [0.7-5.5] ppm. Ventricular volume (VV) ranged from 3.0-to-28.9 ml and UnmWM/Total brain volume (TBV) ratio from 0.32-to-0.53. Linear Regression-analysis between VV and ETCOc and between UnmWM/TBV ratio and ETCOc showed a positive and negative correlation respectively (r=0.56, p< 0.02 and r= -0.73, p< 0.0001). Mulitple LR analysis (dependent Variable: UnmWM/TBV ratio; independent variables: ETCOc; GA; amnionitis; smoking; PIVH; and PDA) showed that only ETCOc was (inversely) related to the UnmWM/TBV ratio (Part F-test: 11.3), suggesting a relation between the height of ETCOc and loss of unmyelinated WM. Suggestion: ETCOc levels shortly after birth, may express oxidative stress and inflammation in the perinatal period, were related with damage of the vulnerable unmyelinated white matter in the preterm infant.

Early end-tidal carbon monoxide levels and neurodevelopmental outcome at 3 years 6 months of age in preterm infants

Increased end-tidal carbon monoxide (ETCOc) and cytokines in preterm infants are related to bronchopulmonary dysplasia and intraventricular haemorrhages. The aim was to study the predictive value of ETCOc and cytokine levels for long-term outcome. This study comprised 105 very preterm infants (57 males, 48 females; gestational age range 25 wks 5d-31 wks 4d; birthweight 610-2100 g) who were admitted to a neonatal intensive care unit between 1 February and 31 December 2002. ETCOc, plasma tumour necrosis factor alpha (TNF-α) and interleukins (IL) 6 and 8, and malondialdehyde (MDA, a marker of lipid peroxidation), were measured at days 1, 3, and 5 of life and related to outcome at 3 years 6 months of age (Griffiths Mental Developmental Scales). Of the 105 infants, 69 were eligible for follow-up (37 males; 32 females; bronchopulmonary dysplasia, n = 12). ETCOc at 0 to 24 hours was higher in infants with adverse outcome (Griffiths developmental quotient <85, n = 15) compared with favourable outcome (2.7SD 0.7 vs 2.0SD 0.5; p < 0.05). MDA and cytokines did not differ between groups. Regression analysis with bootstrapping of independent variables (gestational age, birthweight, ETCOc, TNF-α, IL-6, IL-8, and bronchopulmonary dysplasia) showed that ETCOc was the only parameter that correlated with outcome. The sensitivity and negative predictive value of ETCOc for adverse outcome were 93% and 85% respectively. Adverse neurodevelopmental outcome is associated with increased endogenous carbon monoxide. ETCOc less than 2.0 ppm during the first day indicates a favourable outcome.

Prediction of bronchopulmonary dysplasia

ObjectiveTo determine whether elevation of a biological marker of inflammation would be a better predictor of bronchopulmonary dysplasia (BPD) development than lung function measurement results.DesignProspective study.SettingTertiary neonatal intensive care unit.Patients78...

ELEVATED EXHALED CARBON MONOXIDE CONCENTRATION IN HEMOGLOBINOPATHIES AND ITS RELATION TO RED BLOOD CELL TRANSFUSION THERAPY

In this study, the authors examined a possible role of measurements of end-tidal carbon monoxide (CO), corrected for inhaled CO (ETCOc), as a noninvasive screening tool for hemoglobinopathies and as an indicator for when transfusions would be required in patients receiving chronic transfusions. ETCOc measurements were obtained in subjects with sickle cell disease (n = 18), thalassemia (n = 21), and healthy controls (n = 62). ETCOc values less than 3 parts per million (ppm) yielded a positive predictive value of 93% and negative predictive value of 94% in identifying hemoglobinopathies. Subsequently, 7 subjects with thalassemia had laboratory parameters and ETCOc measured over 2 transfusion cycles. ETCOc values were 4.90 ± 0.32 ppm (mean ± SD), with 89% of values being above normal (≥3 ppm). Pretransfusion ETCOc levels significantly correlated with pretransfusion reticulocyte count (r = .96, P <.001), but not with pretransfusion hemoglobin (r = .44, P = .16) or pretransfusion soluble transferrin receptors (sTfR, r = .52, P = .10). In conclusion, we found that patients with hemoglobinopathies have ETCOc values above the range for healthy controls and ETCOc measurements can be used as an adjunct to hemoglobin measurements to determine the proper timing of transfusions.

Cardiopulmonary Bypass Increases Endogenous Carbon Monoxide Production

Endogenous carbon monoxide (CO) production results from heme metabolism catalyzed by heme oxygenase (HO) enzymes of which HO-1 is inducible by oxidative stress. Cardiopulmonary bypass provokes oxidative stress associated with systemic and pulmonary inflammatory responses. Therefore, the authors hypothesized that cardiopulmonary bypass is associated with an increase in endogenous carbon monoxide production. A prospective, observational study. A cardiothoracic operating room. Forty patients undergoing cardiac surgery with cardiopulmonary bypass. None. End-tidal CO levels and arterial carboxyhemoglobin concentrations were measured before and after cardiopulmonary bypass. End-tidal CO concentrations and carboxyhemoglobin levels were increased significantly after cardiopulmonary bypass as compared with prebypass values (median [interquartile range]: end-tidal CO levels: 33 [20-42] ppm v 22 [16-32] ppm, p < 0.01; carboxyhemoglobin 1.3% [1.0%-1.3%] v 0.9% [0.6%-1.0%], p < 0.01). To exclude that the observed increases were caused by CO accumulation during CPB, the authors also assessed carboxyhemoglobin concentrations in the arterial and venous limb of the oxygenator, indicating that CO is eliminated across the membrane oxygenator during CPB. Cardiac surgery with cardiopulmonary bypass is associated with an increase in endogenous CO production.

Oxidative Stress and Proinflammatory Cytokine Levels are Increased in Premature Neonates of Preeclamptic Mothers with HELLP Syndrome

Background: Respiratory distress syndrome (RDS) incidence is increased in infants of preeclamptic mothers with hemolysis, elevated liver enzymes, low platelets (HELLP) syndrome. RDS and HELLP syndrome have been associated with oxidative stress and inflammatory processes. Objectives: We hypothesize that end-tidal carbon monoxide corrected for inhaled CO (ETCOc), malondialdehyde (MDA) (markers of oxidative stress) and proinflammatory cytokine (IL-6, IL-8) production are higher in infants of preeclamptic mothers with HELLP syndrome than in those of preeclamptic mothers without HELLP syndrome. Methods: Prospective study of 36 infants of preeclamptic mothers (GA <32 weeks) admitted to the Neonatal Intensive Care Unit. ETCOc was measured at 0–12, 48–72 and 168 h postnatally using the CO-Stat™ End-Tidal Breath Analyzer. Simultaneously, blood was sampled for MDA, IL-8 and IL-6. Results: At 0–12 h, ETCOc, MDA and IL-8 values (median[range]) were significantly higher in HELLP infants than in infants from preeclamptic mothers without HELLP (ETCOc 2.2 [1.5–3.9] vs. 1.8 [0.5–2.9] ppm; MDA 2.3 [1.3–4.1] vs. 1.5 [0.4–3.1] µmol/l; IL-8 145 [24–606] vs. 62 [26–397] pg/ml; all p <0.05). MDA remained significantly higher during the first 168 h of life (2.3 [0.8–5.8] vs. 1.1 [0.8–3.7] µmol/l, p = 0.02). Conclusion: Oxidative stress and proinflammatory cytokine levels are increased in infants of preeclamptic mothers with HELLP syndrome. These processes may cause inactivation of surfactant explaining the increased RDS incidence in these infants.

End Tidal Carbon Monoxide: A New Method to Detect Hyperbilirubinemia in Newborns

Jaundice is the most common medical condition affecting term and preterm infants. Hyperbilirubinemia, if left untreated can have devastating neurological outcomes in the infant. Current methods used to detect hyperbilirubinemia include visual inspection, transcutaneous testing and blood sampling. This article will discuss end tidal carbon monoxide testing and its use in determining hyperbilirubinemia. A brief review of hyperbilirubinemia and bilirubin physiology will be addressed. A review of the literature will examine the accuracy and efficacy of end tidal carbon monoxide testing and its use in the Neonatal Intensive Care Unit (NICU).