Comparison of Local and Systemic Inflammation During Invasive Versus Noninvasive Ventilation in Rats

The impact of noninvasive ventilation (NIV) on local and systemic inflammation is poorly characterized, particularly when compared with invasive mechanical ventilation (IMV). We sought to quantify the local and systemic inflammatory response of these 2 respiratory treatments in rats with lipopolysaccharide (LPS)-induced lung injury (LPS-injured) and healthy rats. Animals were subjected to 4 h of NIV or IMV treatments at noninjurious settings, or 4 h of control treatment in which healthy or LPS-injured animals remained spontaneously breathing under isoflurane anesthesia with no respiratory support. Cytokines were then quantified in the serum and lung tissue by multiplex enzyme-linked immunosorbent assay. Contrary to our hypothesis, there were no significant differences in cytokine levels in serum or lung when comparing the NIV- and IMV-treated groups; this was true in both LPS-injured and healthy rats. However, within the LPS-injured group, pulmonary levels of interleukin (IL)-1α, IL-6, and tumor necrosis factor α were significantly lower in the NIV-treated group than in control but not in the IMV-treated group compared with control. We conclude that NIV, unlike IMV, could attenuate local inflammation.

Oxidative Stress Biomarker Decreased in Preterm Neonates Treated With Kangaroo Mother Care

OBJECTIVE

Due to physiological and metabolic immaturity, prematurely born infants are at increased risk because of maternal separation in many neonatal intensive care units (NICUs). The stress induced from maternal-infant separation can lead to well-documented short-term physiologic instability and potentially lifelong neurological, sociological, or psychological sequelae. Based on previous studies of kangaroo mother care (KMC) that demonstrated improvement in physiologic parameters, we examined the impact of KMC on physiologic measures of stress (abdominal temperature, heart rate, oxygen saturation, perfusion index, near-infrared spectrometry), oxidative stress, and energy utilization/conservation in preterm infants.

METHODS

In this randomized, stratified study of premature neonates, we compared the effects on urinary concentrations of biomarkers of energy utilization and oxidative stress of 1 hr of KMC versus incubator care on Day 3 of life in intervention-group babies (n = 26) and control-group babies (n = 25), respectively. On Day 4, both groups received 1 hr of KMC. Urinary samples were collected 3 hr before and 3 hr after intervention/incubator care on both days. Energy utilization was assessed by measures of adenosine triphosphate (ATP) degradation (i.e., hypoxanthine, xanthine, and uric acid). Oxidative stress was assessed using urinary allantoin. Mixed-models analysis was used to assess differences in purine/allantoin.

RESULTS

Mean allantoin levels over Days 3 and 4 were significantly lower in the KMC group than in the control group (p = .026).

CONCLUSIONS

Results provide preliminary evidence that KMC reduces neonatal oxidative stress processes and that urinary allantoin could serve as an effective noninvasive marker for future studies.

Oral dextrose reduced procedural pain without altering cellular ATP metabolism in preterm neonates: a prospective randomized trial

OBJECTIVE

To examine the effects of 30% oral dextrose on biochemical markers of pain, adenosine triphosphate (ATP) degradation, and oxidative stress in preterm neonates experiencing a clinically required heel lance.

STUDY DESIGN

Utilizing a prospective study design, preterm neonates that met study criteria (n = 169) were randomized to receive either (1) 30% oral dextrose, (2) facilitated tucking, or (3) 30% oral dextrose and facilitated tucking 2 min before heel lance. Plasma markers of ATP degradation (hypoxanthine, uric acid) and oxidative stress (allantoin) were measured before and after the heel lance. Pain was measured using the premature infant pain profile-revised (PIPP-R).

RESULTS

Oral dextrose, administered alone or with facilitated tucking, did not alter plasma markers of ATP utilization and oxidative stress.

CONCLUSION

A single dose of 30% oral dextrose, given before a clinically required heel lance, decreased signs of pain without increasing ATP utilization and oxidative stress in premature neonates.

Referral for Ophthalmology Evaluation and Visual Sequelae in Children With Primary Brain Tumors

IMPORTANCE

Visual impairment in children with brain tumors has received limited attention, as most pediatric neuro-oncology clinical trials neither require ophthalmologic evaluation on enrollment nor monitor effects of treatment on visual function during and after treatment.

OBJECTIVE

To investigate ophthalmology referral patterns for children with primary brain tumors, the prevalence of visual sequelae, and the association between tumor characteristics and vision-related diagnoses.

DESIGN, SETTING, AND PARTICIPANTS

This retrospective cohort study included 141 children with primary brain tumors treated at Loma Linda University Children's Hospital and Eye Institute, a university-based tertiary referral center, between January 2013 and September 2017. Data analysis was completed in March 2019.

INTERVENTION

Comprehensive ophthalmologic evaluation for children with primary brain tumors.

MAIN OUTCOMES AND MEASURES

Percentage of patients with ophthalmology evaluation, prevalence of abnormal ophthalmic findings, and their association with tumor characteristics.

RESULTS

A total of 141 children (73 [52%] male; median [range] age, 7 [0-18] years) with primary brain tumors were enrolled in this study. Seventy-three patients (41 [52%] male; median [range] age, 8 [0-17] years) never had formal ophthalmologic evaluation. Sixty-eight patients (32 [48%] male; median [range] age, 7 [0-18] years) were evaluated by 1 of 4 board-certified, fellowship-trained pediatric and/or neuro-ophthalmologists for any visual impairment over a total of 222 visits. Five-year overall survival for patients who had eye examination was not significantly different from those who did not (mean [SD] survival, 78.3% [6.2%] vs 84.9% [4.7%]). Median (range) time from tumor diagnosis to initial ophthalmologic evaluation was 9 (0-94) months. Only 10 of 68 children (15%) presented with visual symptoms at tumor diagnosis, while 61 of 68 (90%) had abnormal findings on examination, including strabismus (41 [60%]), visual acuity impairment (37 [54%]), amblyopia (26 [38%]), papilledema (24 [35%]), visual field defects (13 [19%]), optic atrophy (12 [18%]), and keratopathy (10 [15%]). Strabismus occurred more frequently in patients with posterior fossa tumors (26 of 68 in posterior fossa vs 15 of 68 in other locations; P = .02). The presence of visual field defects in patients with no visual symptoms was 15% (9 of 58). Radiation was significantly associated with amblyopia (odds ratio, 4.5; 95% CI, 1.2-15.7; P = .02).

CONCLUSIONS AND RELEVANCE

In this study, more than 50% of children with primary brain tumors were not referred for ophthalmologic evaluation. Although visual symptoms were uncommon, visual impairments occurred more frequently than previously reported. Ophthalmologic evaluation is recommended to identify and manage visual impairment and prevent permanent vision loss in children with brain tumors.

Cerebral autoregulation is minimally influenced by the superior cervical ganglion in two- week-old lambs, and absent in preterm lambs immediately following delivery

Cerebral vessels in the premature newborn brain are well supplied with adrenergic nerves, stemming from the superior cervical ganglia (SCG), but their role in regulation of blood flow remains uncertain. To test this function twelve premature or two-week-old lambs were instrumented with laser Doppler flow probes in the parietal cortices to measure changes in blood flow during changes in systemic blood pressure and electrical stimulation of the SCG. In lambs delivered prematurely at ∼129 days gestation cerebral perfusion and driving pressure demonstrated a direct linear relationship throughout the physiologic range, indicating lack of autoregulation. In contrast, in lambs two-weeks of age, surgical removal of one SCG resulted in ipsilateral loss of autoregulation during pronounced hypertension. Electrical stimulation of one SCG elicited unilateral increases in cerebral resistance to blood flow in both pre-term and two-week-old lambs, indicating functioning neural pathways in the instrumented, anesthetized lambs. We conclude cerebral autoregulation is non-functional in preterm lambs following cesarean delivery. Adrenergic control of cerebral vascular resistance becomes effective in newborn lambs within two-weeks after birth but SCG-dependent autoregulation is essential only during pronounced hypertension, well above the normal range of blood pressure.

Prevention of postpartum smoking relapse in mothers of infants in the neonatal intensive care unit

OBJECTIVE

Approximately 40% of women who smoke tobacco quit smoking during pregnancy, yet up to 85% relapse after delivery. Those who resume smoking often do so by 2 to 8 weeks postpartum. Smoking mothers are more than twice as likely to quit breastfeeding by 10 weeks postpartum. The hospitalization of a newborn, while stressful, is an opportunity to emphasize the importance of a smoke-free environment for babies. Supporting maternal-infant bonding may reduce maternal stress and motivate mothers to remain smoke free and continue breastfeeding. The objective of this study was to reduce postpartum smoking relapse and prolong breastfeeding duration during the first 8 weeks postpartum in mothers who quit smoking just before or during pregnancy and have newborns admitted to the Neonatal Intensive Care Unit (NICU).

STUDY DESIGN

This study was an Institutional Review Board-approved prospective randomized clinical trial. After informed consent, mothers of newborns admitted to the NICU were randomized to a control or intervention group. Both groups received weekly encouragement to remain smoke free and routine breastfeeding support. Mothers in the intervention group were also given enhanced support for maternal-infant bonding including information about newborn behaviors, and were encouraged to frequently hold their babies skin-to-skin.

RESULT

More mothers were smoke free (81 vs 46%, P<0.001) and breastfeeding (86 vs 21%, P<0.001) in the intervention than in the control group at 8 weeks postpartum.

CONCLUSION

Interventions to support mother-infant bonding during a newborn's hospitalization in the NICU are associated with reduced rates of smoking relapse and prolonged duration of breastfeeding during the first 8 weeks postpartum.

Inhaled nitric oxide therapy increases blood nitrite, nitrate, and s-nitrosohemoglobin concentrations in infants with pulmonary hypertension

OBJECTIVE

To measure the circulating concentrations of nitric oxide (NO) adducts with NO bioactivity after inhaled NO (iNO) therapy in infants with pulmonary hypertension.

STUDY DESIGN

In this single center study, 5 sequential blood samples were collected from infants with pulmonary hypertension before, during, and after therapy with iNO (n = 17). Samples were collected from a control group of hospitalized infants without pulmonary hypertension (n = 16) and from healthy adults for comparison (n = 12).

RESULTS

After beginning iNO (20 ppm) whole blood nitrite levels increased approximately two-fold within 2 hours (P<.01). Whole blood nitrate levels increased to 4-fold higher than baseline during treatment with 20 ppm iNO (P<.01). S-nitrosohemoglobin increased measurably after beginning iNO (P<.01), whereas iron nitrosyl hemoglobin and total hemoglobin-bound NO-species compounds did not change.

CONCLUSION

Treatment of pulmonary hypertensive infants with iNO results in increases in levels of nitrite, nitrate, and S-nitrosohemoglobin in circulating blood. We speculate that these compounds may be carriers of NO bioactivity throughout the body and account for peripheral effects of iNO in the brain, heart, and other organs.

Direct equilibrium dialysis compared with two non-dialysis free T4 methods in premature infants

OBJECTIVE

To compare the incidence of low free T4 values reported by a direct equilibrium dialysis method to their incidence reported by 2 non-dialysis methods.

STUDY DESIGN

Ninety-five infants, < or = 33 weeks gestational age at birth, admitted to Loma Linda University Children's Hospital before day 3 of life were studied. Infants were grouped by gestational age ranges: < or = 27, 28-30, and 31-33 weeks. Free T4 determinations were measured at 3, 7, and 14 days of life with 3 different free T4 methods. Gestational age-specific newborn reference ranges were available for the direct equilibrium dialysis method only. The only reference ranges available for the non-dialysis free T4 methods were not gestational age specific. Using available reference ranges we classified free T4 values as either low or not low. The incidence of low free T4 values was compared at 3, 7, and 14 days of life.

RESULTS

Low direct equilibrium dialysis free T4 values were substantially less frequent than non-dialysis free T4 values.

CONCLUSION

Substantial free T4 inconsistencies occur between dialysis and non-dialysis free T4 methods in preterm infants. It is unclear how much of this inconsistency is method dependent and how much is reference range dependent.

Elevated total peripheral leukocyte count may identify risk for neurological disability in asphyxiated term neonates

OBJECTIVE

The present study investigated the relationship between neurologic outcome and total circulating white blood cell (WBC) and absolute neutrophil counts (ANCs) in the first week of life in term infants with hypoxic-ischemic encephalopathy (HIE).

STUDY DESIGN

Long-term neurologic outcome at 18 months was measured retrospectively in 30 term neonates with HIE using the Pediatric Cerebral Performance Category Scale (PCPCS) score with outcomes dichotomized as either good or poor. We then compared white blood cell and ANC levels during the first 4 days of life and magnetic resonance imaging (MRI) obtained within the first month life between the two PCPCS groups. MRI was quantified using a validated scoring system.

RESULTS

Neonates with good long-term outcomes had significantly lower MRI scores (indicating lesser injury) than neonates with poor outcomes. More importantly, neonates with poor outcomes had significantly higher WBC and ANC levels as early as12 h after birth and up to 96 h after birth compared to those with good outcomes. These data suggest that elevated peripheral neutrophil counts in the first 96 h of life may signal or predict adverse long-term outcome.

CONCLUSIONS

Our findings suggest that elevated peripheral neutrophil counts in the first 96 h of life in term infants with HIE may contribute to abnormal neurodevelopmental outcome.

Use of opioids in asphyxiated term neonates: effects on neuroimaging and clinical outcome

Perinatal asphyxia is a common cause of neurologic morbidity in neonates who are born at term. Asphyxiated neonates are frequently treated with analgesic medications, including opioids, for pain and discomfort associated with their care. On the basis of previous laboratory studies suggesting that opioids may have neuroprotective effects, we conducted a retrospective review of medical records of 52 neonates who were admitted to our neonatal intensive care unit between 1995 and 2002 and had undergone magnetic resonance imaging (MRI) of the brain. Our review revealed that 33% of neonates received morphine or fentanyl. The neonates who received opioids also had experienced hypoxic/ischemic insults of greater magnitude as suggested by higher plasma lactate levels and lower 5-min Apgar scores. It is interesting that the MRI studies of neonates who were treated with opioids during the first week of life demonstrated significantly less brain injury in all regions studied. More important, follow-up studies of a subgroup of opioid-treated neonates whose MRI scans were obtained in the second postnatal week had better long-term neurologic outcomes. Our results suggest that the use of opioids in the first week of life after perinatal asphyxia have no significant long-term detrimental effects and may increase the brain's resistance to hypoxic-ischemic insults.

Incidence of low free T4 values in premature infants as determined by direct equilibrium dialysis

BACKGROUND

The incidence of transient reductions in serum free T(4) (FT(4)) in premature infants may be overestimated because certain FT(4) analytical methods underestimate FT(4) concentrations. Transient reductions of FT(4) measurements have been reported in the majority of premature newborn infants. Direct equilibrium dialysis (DED) does not underestimate FT(4) concentrations and is the best available technique to measure serum FT(4) in the premature infant.

OBJECTIVE

To evaluate the incidence of low FT(4) concentrations in premature infants using DED to measure FT(4).

DESIGN/METHOD

We measured FT(4) by DED in infants with birth weight <1500 g. Infants were excluded if the following conditions were present: congenital anomalies or maternal thyroid disorders. Free T(4) was measured at 14 days of life. Low FT(4) was defined using a statistical definition of FT(4) measurements <10.3 pmol/l (0.8 ng/dl).

RESULTS

Free T(4) was measured by DED in 114 infants. Low FT(4) levels were seen in nine infants (7.9%).

CONCLUSION

The incidence of low FT(4) was much lower than previously reported when FT(4) was measured using DED indicating that methodological issues are involved in the variability among estimates of the frequency of transient reduction in FT(4).

Moderate acute rejection detected during annual catheterization in pediatric heart transplant recipients

BACKGROUND

Acute rejection commonly occurs within the first year after heart transplantation, and then decreases in frequency with time. Recently, the long-term utility of endomyocardial biopsy during routine annual catheterization has been questioned. The purpose of this study was to retrospectively review the prevalence of biopsy-proven rejection during routine annual catheterization in our patient population, determine whether biopsies late after transplant are useful, and identify factors that correlate with late unsuspected rejection.

METHODS

Biopsy results from the annual catheterization were evaluated from 1986 to August 2000. The prevalence of moderate rejection was evaluated and compared with the patient's immunosuppressive regimen; the prevalence of late rejection; and how late rejection correlated with recipient age, number of first-year rejections and presence of sub-therapeutic cyclosporine.

RESULTS

A total of 1108 biopsies were performed in 269 children with a mean follow-up of 5 +/- 3 years (median 5 years, range 1 to 11 years). Three-drug immunosuppressive therapy, including steroids, was used in 93 patients. There was a persistent 8% to 10% prevalence of moderate rejection at up to 10 years post-transplantation. Moderate rejection was more likely in patients: (1). on 3-drug immunosuppressive therapy; (2). with a recipient age >1 year; and (3). with a relatively lower cyclosporine level.

CONCLUSIONS

These data suggest that continued surveillance of pediatric transplant patients for acute rejection is indicated for long-term follow-up.

Comparison of 2 iron doses in infants receiving recombinant human erythropoietin therapy

OBJECTIVE

To compare iron sufficiency in premature infants receiving high-dose recombinant human erythropoietin (r-HuEPO), 1200 IU/kg per week, supplemented with 6 or 12 mg/kg per day of enteral iron.

DESIGN

We conducted a prospective, double-blind, controlled study of premature infants receiving r-HuEPO therapy, randomly assigned to receive 2 different doses of iron. Measurements of ferritin, iron, total iron-binding capacity, reticulocyte count, hemoglobin level, and hematocrit were obtained at baseline, 4, and 6 weeks. Transferrin saturation was calculated; the number of blood transfusions and the incidences of sepsis were recorded.

SETTING

This study was performed in the neonatal intensive care unit at Loma Linda University Children's Hospital, Loma Linda, Calif.

SUBJECTS

Infants with a gestational age of 32 weeks or younger, older than 7 days, and receiving r-HuEPO therapy from March 1, 1997, to June 30, 1998, were eligible for the study. Infants were randomly assigned to receive 6 mg/kg per day or 12 mg/kg per day of enteral iron during a course of r-HuEPO therapy for 4 to 6 weeks.

RESULTS

Sixty-four infants were enrolled in the study. Twelve infants did not complete the study; 52 completed 4 weeks and 41 completed 6 weeks of the study. While ferritin levels and transferrin saturation decreased in both groups over the study period, there were no differences between the 2 study groups.

CONCLUSIONS

Infants receiving high-dose r-HuEPO therapy (1200 IU/kg per week) decrease their ferritin levels (measure of iron stores) even when receiving high enteral iron supplementation. Given that the ferritin levels were similar between the 2 groups, we speculate that the additional iron either was not absorbed or was not stored.

QTc interval in infants receiving cisapride

OBJECTIVE

To examine the effect of cisapride on the corrected QT (QTc) interval in infants over a 14-day period.

STUDY DESIGN

A prospective cohort study of infants receiving cisapride (0.8 mg/kg per day). Twelve-lead electrocardiograms were obtained before and 3, 5, 7, and 14 days after cisapride initiation.

RESULTS

Fifty infants completed the study; none had arrhythmias. Fifteen of 50 infants (30%) developed QTc interval > or =450 msec; QTc interval normalized in 13 of 15 infants. Infants with QTc interval on day 3 > or =2 standard deviations above the mean baseline QTc interval (401+40 msec) were more likely to develop prolonged QTc interval (p<0.0001).

CONCLUSION

QTc interval prolongation was noted in 30% of infants. Subsequently, the majority of those infants had QTc interval normalization by day 14 of cisapride therapy. QTc interval 3 days following cisapride initiation may identify infants at risk for transient QTc interval prolongation. With appropriate monitoring, hospitalized infants receiving cisapride may have improved gastrointestinal motility without cardiac morbidity.

Evaluation of the safety of short-acting nifedipine in children with hypertension

Concerns regarding the safety of nifedipine emerged in 1995 with the report of an increased risk of myocardial infarction associated with adult patients receiving short-acting calcium channel blockers. There have been few case reports of adverse events in children. The purpose of this study is to investigate the effect on blood pressure (BP) and the incidence of adverse events associated with nifedipine in our pediatric population. We conducted a retrospective chart review of pediatric patients who received nifedipine. We recorded the dose administered, all BP measurements and all adverse events reported within six hours of a nifedipine dose regardless of the likelihood that those events were related to the nifedipine dose. 1,746 doses of nifedipine in 166 pediatric patients were reviewed. Systolic BP decreased by a mean of 17% and a maximum of 63%. Diastolic BP decreased by a mean of 28% and a maximum of 89%. Adverse events included: a) change in neurologic status, six cases; b) hypotension, two cases; c) oxygen desaturation, 16 cases. Neurologic events occurred in 33% of patients with acute CNS injury and 3.6% of all patients. Short-acting nifedipine is an important and effective oral antihypertensive agent which can be safely used for the treatment of hypertensive emergencies in children. It should be used with caution in children with acute CNS injury.

Reference ranges for thyroid function tests in premature infants beyond the first week of life

OBJECTIVES

To establish reference ranges for the more sensitive assays of thyrotropin and the best available assays of free thyroxine in premature infants after the first week of life.

STUDY DESIGN

Free thyroxine measurements by direct equilibrium dialysis and thyrotropin measurements by third generation immunometric assay were measured in 120 healthy premature infants 25 to 36 weeks' gestation at birth and every 3 weeks until hospital discharge. Infants were stratified by postconceptional age. Differences in free thyroxine and thyrotropin levels among groups were determined by ANOVA. Correlations between hormone measurements and gestational and postnatal ages were sought by linear regression analysis. Reference ranges were determined as arithmetic (free thyroxine) and geometric (thyrotropin) mean+/-2 SD ranges.

RESULTS

From 120 infants, 164 samples were obtained and grouped by postconceptional age at sampling. Free thyroxine was not different among postconceptional age groups and did not correlate with gestational or postnatal age. The free thyroxine reference range based on these data was 10 to 33 pmol/l (0.8 to 2.6 ng/dl). Thyrotropin did not correlate with gestational age. There was a clinically trivial but statistically significant (r(2)=0.03, p<0.05) correlation of thyrotropin with postnatal age. The thyrotropin reference based on these data was 0.8 to 12 mU/l.

CONCLUSIONS

Free thyroxine was closely regulated in these premature infants and levels were similar to those in older children and adults, once the natal surge in thyrotropin has subsided. After the first week of life a single range for each hormone appeared appropriate for all premature infants until 40 weeks postconceptional age.

The medium-term findings in coronary arteries by intravascular ultrasound in infants and children after heart transplantation

OBJECTIVES

The study purposes were to determine 1) whether intravascular ultrasound (IVUS) was more sensitive than angiography for the detection of post-transplant coronary artery disease (PTCAD) in pediatric patients; and 2) whether those transplanted as neonates reacted differently than older patients.

BACKGROUND

Experience with IVUS for the diagnosis of PTCAD in children is limited.

METHODS

Patients were divided into two groups: those transplanted as neonates (early group) and those transplanted in infancy or childhood (late group). Morphometric analysis was performed, including maximal intimal thickness (MIT) and intimal index (II). Stanford classification was used to grade lesion severity. Acute rejection and cytomegalovirus (CMV) status were correlated with MIT and II.

RESULTS

Thirty children were studied (early group, n = 13; late group, n = 17). All segments studied were angiographically normal. Mean MIT and mean II were significantly greater in the late group (0.26 +/- 0.14 vs. 0.13 +/- 0.04 mm, p < 0.001 and 0.11 +/- 0.07 vs. 0.07 +/- 0.03 mm, p = 0.04, respectively). There was a significant correlation between MIT and II in those who had acute rejection in the late group. Patients in the late group who were CMV-positive had a significantly higher MIT compared with those in the late group with negative serology (p = 0.04).

CONCLUSIONS

Intravascular ultrasound was more sensitive than angiography in detecting PTCAD after pediatric heart transplantation. There is a possible role for acute rejection and CMV in the development of PTCAD.

Extracorporeal membrane oxygenation for perioperative support in neonatal and pediatric cardiac transplantation

Currently there is a lack of consensus on guidelines in the clinical application of extracorporeal membrane oxygenation (ECMO) in neonatal and pediatric cardiac transplantation patients. In this context, given the limited data presently available through the Extracorporeal Life Support Organization (ELSO) Registry, we conducted a preliminary survey to specifically evaluate the practice of using ECMO as a bridge to cardiac transplantation or as posttransplantation therapy for failure to wean from cardiopulmonary bypass or graft failure. We received responses to our questionnaire from 95 of 118 (81%) centers located in the U.S.A. and abroad. Of the 95 centers that responded, 36 were performing neonatal/pediatric cardiac transplants, with 29 centers reporting the concomitant use of ECMO to support cardiac transplant patients. There was wide variability in the responses from the 29 centers to a selected list of relative ECMO contraindications. However, only 7 centers had specific ECMO entry criteria for cardiac transplant patients. Fifteen of the 29 centers provided relevant data on cardiac transplant patients including the proportions of neonatal (11 of 37) and pediatric (63 of 217) patients requiring ECMO; neonatal (2 of 5) and pediatric (16 of 27) patients surviving to transplant; and neonatal (1 of 5) and pediatric (12 of 27) patients surviving to hospital discharge. These findings confirm the important role of ECMO in providing perioperative support in neonatal and pediatric cardiac transplantation patients. However, the lack of consensus among centers contributes to uncertainty in the decision making process to offer ECMO and to utilize ECMO effectively in this high risk population. We recommend that institution-specific information be collected, either using the ELSO Registry (or by a similar multicentric database) to develop specific guidelines for ECMO applications in cardiac transplant patients, and to carefully monitor and follow up EMCO treated patients to further evaluate the efficacy of this limited resource.

Serum free thyroxine concentration is not reduced in premature infants with respiratory distress syndrome

OBJECTIVE

We used improved methods of assay to determine whether pituitary-thyroid function is altered in premature infants with respiratory distress syndrome (RDS) during the first week of postnatal life.

METHODS

Serum free thyroxine (T4) was measured by direct equilibrium dialysis, total thyroxine (TT4) by radioimmunoassay, and thyrotropin by a sensitive immunometric assay in 90 premature infants (45 healthy control subjects and 45 with RDS) during their first week of life after 25 to 30 weeks of gestation. Infants in the RDS group received exogenous surfactant therapy.

RESULTS

Free T4 and thyrotropin concentrations of infants were not significantly different between RDS and control groups. As expected, infants with RDS had significantly lower serum total T4 concentrations compared with control infants (p < 0.001). This difference was present even after stratification for gestational age (25- to 27-week group, p = 0.012; 28- to 30-week group, p = 0.002). Lower total T4 concentrations were attributable to lower T4 binding to serum proteins among infants with RDS compared with control subjects, especially in the 25- to 27-week gestation group (p = 0.0075).

CONCLUSION

These data indicate that pituitary-thyroid function is not altered in premature infants with RDS. The low total T4 state in these premature infants is attributable solely to reduced serum T4 binding, as is often seen in acute nonthyroidal illnesses.

Infrared end-tidal CO2 measurement does not accurately predict arterial CO2 values or end-tidal to arterial PCO2 gradients in rabbits with lung injury

End-tidal PCO2 (PETCO2) measurements from two commercially available neonatal infrared capnometers with different sampling systems and a mass spectrometer were compared with arterial PCO2 (PaCO2) to determine whether the former could predict the latter in mechanically ventilated rabbits with and without lung injury. The effects of tidal volume, ventilator frequency and type of lung injury on the gradient between PETCO2 and PaCO2 (delta P(a-ET)CO2) were evaluated. Twenty rabbits were studied: 10 without lung injury, 5 with saline lavage and 5 with lung injury by meconium instillation. Paired measurements of PETCO2 by two infrared capnometers and a mass spectrometer were compared to PaCO2. In the rabbits without lung injury, the values from the infrared capnometers and mass spectrometer correlated strongly with PaCO2 (r > or = 0.91) despite differences in the slopes of the linear regression between PETCO2 and PaCO2 and in delta P(a-ET)CO2 (P < 0.05). Values from the mainstream IR-capnometer more closely approximated the line of identity than the regression between the sidestream IR-capnometer values or the mass spectrometer and PaCO2, but tended to overestimate PaCO2. The delta P(a-ET)CO2 was similar at all tidal volumes and ventilator frequencies, regardless of capnometer type. In the rabbits with induced lung injury, while there was a positive correlation between the slopes of the regression between PETCO2 and PaCO2 for both capnometers (r > or = 0.70), none of the regression slopes approximated the line of identity. The delta P(a-ET)CO2 was greater in rabbits with injured than noninjured lungs (P < 0.05). The delta P(a-ET)CO2 was similar among capnometers regardless of tidal volume, ventilator frequency, or type of lung injury. The 95% confidence interval of plots PaCO2 against PETCO2 was large for rabbits with injured and noninjured lungs.(ABSTRACT TRUNCATED AT 250 WORDS)

Sudden infant death syndrome in infants evaluated by apnea programs in California

Home apnea/bradycardia monitoring is frequently used in the management of infants at increased risk for sudden infant death syndrome (SIDS). However, some infants have died despite evaluation by infant apnea programs, and the benefits of home monitoring remain unproven. To determine the SIDS rate and risk factors of infants evaluated by infant apnea programs, 31 apnea programs and ten home monitor vendors in California were surveyed. Eleven (35%) of the apnea programs and four (40%) of the vendors responded. Information was obtained on 26 infants who died. Thirteen (50%) deaths were due to SIDS. Abnormal sleep studies did not predict death. Fifteen infants died despite a recommendation for home monitoring. Seven deaths occurred in association with technical errors or noncompliance with monitoring. Four deaths were due to nonaccidental trauma. The apnea programs evaluated 3,406 infants during a 5-year period; 1,841 had monitoring recommended. Term infants with apnea, subsequent siblings of SIDS victims, and infants evaluated at referral centers were more likely to have monitoring recommended than premature infants with apnea or infants evaluated at nonreferral centers (P less than .0001). Infants who had monitoring recommended were at equal risk of dying of SIDS as those who did not.

Controlled trial of furosemide therapy in infants with chronic lung disease

To study the effects of furosemide therapy in infants with chronic lung disease (CLD), a double-blind controlled trial was designed. Seventeen infants with evidence of CLD (oxygen requirements greater than 30% at greater than 3 weeks of age and chest radiographic findings consistent with CLD) were studied. Pulmonary function was measured immediately before, and after 48 hours and 7 days of treatment with furosemide (1 mg/kg/12 hr intravenously or 2 mg/kg/12 hr orally) or placebo. Clinical status improved in six of seven infants who received furosemide and in two of 10 infants who received placebo (P less than 0.002). In the furosemide group, ventilator and oxygen requirements decreased (P less than 0.003); minute ventilation, alveolar ventilation, and dynamic compliance increased; and venous admixture decreased (P less than 0.05). There were no significant changes in the placebo group. Our findings suggest that furosemide significantly improves lung function during therapy in infants with CLD and allows earlier weaning from ventilatory support and supplemental oxygen.

Neonatal endotracheal flowmeter for tidal volume, airway pressure, and end-tidal gas

We have designed a new endotracheal flowmeter to measure tidal volume, phasic and mean airway pressures, inspiratory time, and end-tidal PCO2 and PO2 in intubated infants. The flowmeter is light (11 g) and adds minimal dead space (1.0 ml) and resistance (2 cmH2O X 100 ml- X s) to the infant's airway. The volume signal (less than or equal to 10 ml) is linear to 7 Hz, and end-tidal gases can be measured at respiratory rates of 90 breaths/min. This flowmeter is particularly valuable for evaluation of rapid mechanical ventilation of very low birth weight infants.