211 ASSOCIATION OF PLASMA ANTIOXIDANTS AND COGNITIVE OUTCOMES IN NORTHERN IRISH MEN FROM PROSPECTIVE EPIDEMIOLOGICAL STUDY OF MYOCARDIAL INFARCTION (PRIME) STUDY

Background

Oxidative stress and chronic inflammation have been demonstrated to contribute to cognitive decline in older age and the development of neurodegenerative disorders. Antioxidants have been revealed to help mitigate the effects of the damage caused by oxidative stress and inflammation, but their relationship with cognitive decline is not yet fully understood. The aim of this study was to investigate the association between various plasma antioxidant levels and cognitive status in participants from the Prospective Epidemiological Study of Myocardial Infarction (PRIME) study.

Methods

10,600 men were recruited to the PRIME study between 1991-1993 and have been followed up across eleven time points. Baseline health and lifestyle characteristics were assessed, and plasma antioxidants were obtained and quantified. Baseline cognitive status was screened in 2000 using Mini-Mental State Examination (MMSE). Follow up assessment of cognitive status was performed in 2015 with MMSE and Addenbrooke’s Cognitive Examination-Revised (ACE-R) examinations.

Results

2,009 men underwent cognitive assessment in 2000 and 873 men in 2015. At both 2000 and 2015 with the use of the MMSE and ACE-R examinations to assess cognitive status, serum concentration of all the antioxidants except for gamma-tocopherol and lycopene were higher in the men with better cognitive performance at a significant level of p<0.05. Better cognitive performance was associated with more time spent in education and higher level of education achieved at a statistically significant level (p<0.01). Furthermore, those with cognitive impairment were more likely to be older. After adjustments for lifestyle variables with a linear regression model, the only significant variable associated with cognition was time spent in education (B = 0.521, p= 0.02).

Conclusion

The findings suggest that the concentration of plasma antioxidants is associated with cognitive status. Smoking and education, as well as other lifestyle factors were, demonstrated to have an impact on cognitive status.

Evaluation of prognostic risk models for postoperative pulmonary complications in adult patients undergoing major abdominal surgery: a systematic review and international external validation cohort study

BACKGROUND

Stratifying risk of postoperative pulmonary complications after major abdominal surgery allows clinicians to modify risk through targeted interventions and enhanced monitoring. In this study, we aimed to identify and validate prognostic models against a new consensus definition of postoperative pulmonary complications.

METHODS

We did a systematic review and international external validation cohort study. The systematic review was done in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. We searched MEDLINE and Embase on March 1, 2020, for articles published in English that reported on risk prediction models for postoperative pulmonary complications following abdominal surgery. External validation of existing models was done within a prospective international cohort study of adult patients (≥18 years) undergoing major abdominal surgery. Data were collected between Jan 1, 2019, and April 30, 2019, in the UK, Ireland, and Australia. Discriminative ability and prognostic accuracy summary statistics were compared between models for the 30-day postoperative pulmonary complication rate as defined by the Standardised Endpoints in Perioperative Medicine Core Outcome Measures in Perioperative and Anaesthetic Care (StEP-COMPAC). Model performance was compared using the area under the receiver operating characteristic curve (AUROCC).

FINDINGS

In total, we identified 2903 records from our literature search; of which, 2514 (86·6%) unique records were screened, 121 (4·8%) of 2514 full texts were assessed for eligibility, and 29 unique prognostic models were identified. Nine (31·0%) of 29 models had score development reported only, 19 (65·5%) had undergone internal validation, and only four (13·8%) had been externally validated. Data to validate six eligible models were collected in the international external validation cohort study. Data from 11 591 patients were available, with an overall postoperative pulmonary complication rate of 7·8% (n=903). None of the six models showed good discrimination (defined as AUROCC ≥0·70) for identifying postoperative pulmonary complications, with the Assess Respiratory Risk in Surgical Patients in Catalonia score showing the best discrimination (AUROCC 0·700 [95% CI 0·683-0·717]).

INTERPRETATION

In the pre-COVID-19 pandemic data, variability in the risk of pulmonary complications (StEP-COMPAC definition) following major abdominal surgery was poorly described by existing prognostication tools. To improve surgical safety during the COVID-19 pandemic recovery and beyond, novel risk stratification tools are required.

FUNDING

British Journal of Surgery Society.

Racial and geographic variation in effects of maternal education and neighborhood-level measures of socioeconomic status on gestational age at birth: Findings from the ECHO cohorts

Preterm birth occurs at excessively high and disparate rates in the United States. In 2016, the National Institutes of Health (NIH) launched the Environmental influences on Child Health Outcomes (ECHO) program to investigate the influence of early life exposures on child health. Extant data from the ECHO cohorts provides the opportunity to examine racial and geographic variation in effects of individual- and neighborhood-level markers of socioeconomic status (SES) on gestational age at birth. The objective of this study was to examine the association between individual-level (maternal education) and neighborhood-level markers of SES and gestational age at birth, stratifying by maternal race/ethnicity, and whether any such associations are modified by US geographic region. Twenty-six ECHO cohorts representing 25,526 mother-infant pairs contributed to this disseminated meta-analysis that investigated the effect of maternal prenatal level of education (high school diploma, GED, or less; some college, associate's degree, vocational or technical training [reference category]; bachelor's degree, graduate school, or professional degree) and neighborhood-level markers of SES (census tract [CT] urbanicity, percentage of black population in CT, percentage of population below the federal poverty level in CT) on gestational age at birth (categorized as preterm, early term, full term [the reference category], late, and post term) according to maternal race/ethnicity and US region. Multinomial logistic regression was used to estimate odds ratios (OR) and 95% confidence intervals (CIs). Cohort-specific results were meta-analyzed using a random effects model. For women overall, a bachelor's degree or above, compared with some college, was associated with a significantly decreased odds of preterm birth (aOR 0.72; 95% CI: 0.61-0.86), whereas a high school education or less was associated with an increased odds of early term birth (aOR 1.10, 95% CI: 1.00-1.21). When stratifying by maternal race/ethnicity, there were no significant associations between maternal education and gestational age at birth among women of racial/ethnic groups other than non-Hispanic white. Among non-Hispanic white women, a bachelor's degree or above was likewise associated with a significantly decreased odds of preterm birth (aOR 0.74 (95% CI: 0.58, 0.94) as well as a decreased odds of early term birth (aOR 0.84 (95% CI: 0.74, 0.95). The association between maternal education and gestational age at birth varied according to US region, with higher levels of maternal education associated with a significantly decreased odds of preterm birth in the Midwest and South but not in the Northeast and West. Non-Hispanic white women residing in rural compared to urban CTs had an increased odds of preterm birth; the ability to detect associations between neighborhood-level measures of SES and gestational age for other race/ethnic groups was limited due to small sample sizes within select strata. Interventions that promote higher educational attainment among women of reproductive age could contribute to a reduction in preterm birth, particularly in the US South and Midwest. Further individual-level analyses engaging a diverse set of cohorts are needed to disentangle the complex interrelationships among maternal education, neighborhood-level factors, exposures across the life course, and gestational age at birth outcomes by maternal race/ethnicity and US geography.

A review of maternal prenatal exposures to environmental chemicals and psychosocial stressors-implications for research on perinatal outcomes in the ECHO program

Exposures to environmental chemicals and psychosocial stressors during pregnancy have been individually associated with adverse perinatal outcomes related to birthweight and gestational age, but are not often considered in combination. We review types of psychosocial stressors and instruments used to assess them and classes of environmental chemical exposures that are known to adversely impact perinatal outcomes, and identify studies relevant studies. We discuss the National Institutes of Health's Environmental influences on Child Health Outcomes (ECHO) program that has combined existing longitudinal cohorts that include more than 50,000 children across the U.S. We describe future opportunities for investigators to use this important new resource for addressing relevant and critical research questions to maternal health. Of the 84 cohorts in ECHO, 38 collected data on environmental chemicals and psychosocial stressors and perinatal outcomes. The diverse ECHO pregnancy cohorts provide capacity to compare regions with distinct place-based environmental and social stressors.

The Burden of Pediatric Neurocritical Care in the United States

BACKGROUND

Disorders requiring pediatric neurocritical care (PNCC) affect thousands of children annually. We aimed to quantify the burden of PNCC through generation of national estimates of disease incidence, utilization of critical care interventions (CCI), and hospital outcomes.

METHODS

We performed a retrospective cohort analysis of the Kids Inpatient Database over three years to evaluate pediatric traumatic brain injury, neuro-infection or inflammatory diseases, status epilepticus, stroke, hypoxic ischemic injury after cardiac arrest, and spinal cord injury. We evaluated use of CCI, death, length of stay, hospital charges, and poor functional outcome defined as receipt of tracheostomy or gastrostomy or discharge to a medical care facility.

RESULTS

At least one CCI was recorded in 67,058 (23%) children with a primary neurological diagnosis, and considered a PNCC admission. Over half of PNCC admissions had at least one chronic condition, and 23% were treated in children's hospitals. Mechanical ventilation was the most common CCI, but utilization of CCIs varied significantly by diagnosis. Among PNCC admissions, 8110 (12%) children died during hospitalization and 14,067 (21%) children had poor functional outcomes. PNCC admissions cumulatively accounted for over 1.5 million hospital days and over $4 billion in hospital costs in the study years. Most PNCC admissions, across all diagnoses, had prolonged hospitalizations (more than one week) with an average cost of $39.9 thousand per admission.

CONCLUSIONS

This large, nationally representative study shows PNCC diseases are a significant public health burden with substantial risk to children's health. More research is needed to improve outcomes in these vulnerable children.

Quantification of nutritive sucking among preterm and full-term infants

Purpose

We developed summaries of oral bottle-feeding skills among preterm (<37 gestational weeks) and full-term (≥37 gestational weeks) infants using a mechanical device (Orometer) to measure intraoral pressure changes, with accompanying automated software and analytics. We then compared the rates of change in feeding skills over several weeks (feeding trends) between preterm and full-term infants. We also compared group means at 40 weeks post menstrual age (PMA).

Patients and methods

Healthy full-term and preterm infants capable of oral feeding were recruited from the Pediatric Outpatient Clinic at University of California San Francisco, Fresno, and from the Oregon Health & Science University Doernbecher Neonatal Critical Care Unit, respectively. Feeding skill was quantified using an Orometer and automated suck-analysis software. Factor analysis reduced the >40 metrics produced by the Orometer system to the following seven factors that accounted for >99% of the sample covariance: suck vigor, endurance, resting, irregularity, frequency, variability, and bursting. We proposed that these factors represent feeding skills and they served as the dependent variables in linear models estimating trends in feeding skills over time for full-term and preterm infants (maturation). At approximately 40 weeks PMA we compared mean feedings skills between infants born preterm and those born full-term using predictions from our models.

Results

Feeding skills for 117 full-term infants and 82 preterm infants were first captured at mean PMA of 42.3 and 36.0 weeks, respectively. For some feeding skills, preterm and full-term infants showed different trends over time. At 37-40 weeks PMA, preterm infants took approximately 15% fewer sucks than infants born full-term (p=0.06) and generally had weaker suck vigor, greater resting, and less endurance than full-term babies. Preterm infant-feeding skills appeared similar to those of full-term infants upon reaching ≥40 weeks PMA, although preterm infants showed greater variability for all factors.

Conclusion

The Orometer device, accompanying software, and analytic methods provided a framework for describing trends in oral feeding, thereby allowing us to characterize differences in maturation of feeding between healthy preterm and full-term infants.

Monitoring neonates for ototoxicity

OBJECTIVES

Neonates admitted to the neonatal intensive care unit (NICU) are at greater risk of permanent hearing loss compared to infants in well mother and baby units. Several factors have been associated with this increased prevalence of hearing loss, including congenital infections (e.g. cytomegalovirus or syphilis), ototoxic drugs (such as aminoglycoside or glycopeptide antibiotics), low birth weight, hypoxia and length of stay. The aetiology of this increased prevalence of hearing loss remains poorly understood.

DESIGN

Here we review current practice and discuss the feasibility of designing improved ototoxicity screening and monitoring protocols to better identify acquired, drug-induced hearing loss in NICU neonates.

STUDY SAMPLE

A review of published literature.

CONCLUSIONS

We conclude that current audiological screening or monitoring protocols for neonates are not designed to adequately detect early onset of ototoxicity. This paper offers a detailed review of evidence-based research, and offers recommendations for developing and implementing an ototoxicity monitoring protocol for young infants, before and after discharge from the hospital.

Effect of gentamicin and levels of ambient sound on hearing screening outcomes in the neonatal intensive care unit: A pilot study

OBJECTIVE

Hearing loss rates in infants admitted to neonatal intensive care units (NICU) run at 2-15%, compared to 0.3% in full-term births. The etiology of this difference remains poorly understood. We examined whether the level of ambient sound and/or cumulative gentamicin (an aminoglycoside) exposure affect NICU hearing screening results, as either exposure can cause acquired, permanent hearing loss. We hypothesized that higher levels of ambient sound in the NICU, and/or gentamicin dosing, increase the risk of referral on the distortion product otoacoustic emission (DPOAE) assessments and/or automated auditory brainstem response (AABR) screens.

METHODS

This was a prospective pilot outcomes study of 82 infants (<37 weeks gestational age) admitted to the NICU at Oregon Health & Science University. An ER-200D sound pressure level dosimeter was used to collect daily sound exposure in the NICU for each neonate. Gentamicin dosing was also calculated for each infant, including the total daily dose based on body mass (mg/kg/day), as well as the total number of treatment days. DPOAE and AABR assessments were conducted prior to discharge to evaluate hearing status. Exclusion criteria included congenital infections associated with hearing loss, and congenital craniofacial or otologic abnormalities.

RESULTS

The mean level of ambient sound was 62.9 dBA (range 51.8-70.6 dBA), greatly exceeding American Academy of Pediatrics (AAP) recommendation of <45.0 dBA. More than 80% of subjects received gentamicin treatment. The referral rate for (i) AABRs, (frequency range: ∼1000-4000 Hz), was 5%; (ii) DPOAEs with a broad F2 frequency range (2063-10031 Hz) was 39%; (iii) DPOAEs with a low-frequency F2 range (<4172 Hz) was 29%, and (iv) DPOAEs with a high-frequency F2 range (>4172 Hz) was 44%. DPOAE referrals were significantly greater for infants receiving >2 days of gentamicin dosing compared to fewer doses (p = 0.004). The effect of sound exposure and gentamicin treatment on hearing could not be determined due to the low number of NICU infants without gentamicin exposure (for control comparisons).

CONCLUSION

All infants were exposed to higher levels of ambient sound that substantially exceed AAP guidelines. More referrals were generated by DPOAE assessments than with AABR screens, with significantly more DPOAE referrals with a high-frequency F2 range, consistent with sound- and/or gentamicin-induced cochlear dysfunction. Adding higher frequency DPOAE assessments to existing NICU hearing screening protocols could better identify infants at-risk for ototoxicity.

Respiratory morbidity and lung function in preterm infants of 32 to 36 weeks' gestational age

Normal lung development follows a series of orchestrated events. Premature birth interrupts normal in utero lung development, which results in significant alterations in lung function and physiology. Increasingly, there are reports documenting the broad range of complications experienced by infants aged 34 to 36 weeks' gestational age (GA). Our objective was to summarize the evidence demonstrating respiratory system vulnerability in infants aged 34 to 36 weeks' GA and to review the developmental and physiologic principles that underlie this vulnerability. A comprehensive search for studies that reported epidemiologic data and respiratory morbidity was conducted on the PubMed, Medline, Ovid Biosis, and Embase databases from 2000 to 2009 by using medical subject headings "morbidity in late preterm infants," "preterm infants and lung development," "prematurity and morbidity," and "prematurity and lung development." Because the number of studies exclusive to infants aged 34 to 36 weeks' GA was limited, selected studies also included infants aged 32 to 36 weeks' GA. Of the 24 studies identified, 16 were retrospective population-based cohort studies; 8 studies were observational. These studies consistently revealed that infants born at 32 to 36 weeks' GA, including infants of 34 to 36 weeks' GA, experience substantial respiratory morbidity compared with term infants. Levels of morbidity were, at times, comparable to those observed in very preterm infants. The developmental and physiologic mechanisms that underlie the increased morbidity rate and alterations in respiratory function are discussed. We also present evidence to demonstrate that the immaturity of the respiratory system of infants 34 to 36 weeks' GA at birth results in increased morbidity in infancy and leads to deficits in lung function that may persist into adulthood.

Estimates and relationships between aboveground and belowground resource exchange surface areas in a Sitka spruce managed forest

Our knowledge of the nature of belowground competition for moisture and nutrients is limited. In this study, we used an earth impedance method to determine the root absorbing area of Sitka spruce (Picea sitchensis (Bong.) Carr.) trees, making measurements in stands of differing density (2-, 4- and 6-m inter-tree spacing). We compared absorbing root area index (RAI(absorbing); based on the impedance measure) with fine root area index (RAI(fine); based on estimates of total surface area of fine roots) and related these results to investment in conductive roots. Root absorbing area was a near-linear function of tree stem diameter at 1.3 m height. At the stand level, RAI(absorbing), which is analogous to and scaled with transpiring leaf area index (maximum stomatal pore area per unit ground area; LAI(transpiring)), increased proportionally with basal area across the three stands. In contrast, RAI(fine) was inversely propotional to basal area. The ratio of RAI(absorbing) to LAI(transpiring) ranged from 7.7 to 17.1, giving an estimate of the relative aboveground versus belowground resource exchange areas. RAI(absorbing) provides a way of characterizing ecosystem functioning as a physiologically meaningful index of belowground absorbing area.

Functional residual capacity and passive compliance measurements after antenatal steroid therapy in preterm infants

Studies in preterm animal models have shown that antenatal corticosteroids enhance lung maturation by improving a variety of physiologic variables, including lung volumes. Changes in lung volume of preterm infants treated with a full course of antenatal steroids have not been investigated. We hypothesized that a full course of antenatal steroids would significantly increase functional residual capacity (FRC) in treated vs. untreated preterm infants. The objective of our study was to compare FRC and respiratory mechanics in steroid treated vs. untreated preterm infants. FRC and passive respiratory mechanics were prospectively studied within 36 hr of life in 20 infants (25-34 weeks of gestation) who had received a full course of antenatal steroids and in 20 matched untreated preterm infants. FRC was measured with the nitrogen washout method, and respiratory mechanics with the single-breath occlusion technique. Preterm infants who received steroids (n = 20; mean birth weight = 1,230 g; gestational age = 28.8 weeks) had a significantly higher FRC (29.5 vs. 19.3 mL/kg; P < 0.001) than untreated infants (n = 20; birth weight = 1,202 g; gestational age = 28.5 weeks). Passive respiratory system compliance was also increased in treated vs. untreated infants (P < 0.05). In conclusion, FRC and passive respiratory system compliance were significantly improved in preterm infants (25-34 weeks gestation) treated with a full course of antenatal steroids, compared to matched untreated infants. Although this study was not randomized, it confirms that antenatal steroids have important effects on pulmonary function that may contribute to a decreased risk of respiratory distress syndrome in treated preterm infants.

Timing of antenatal corticosteroids and neonatal pulmonary mechanics

OBJECTIVE

We sought to compare lung mechanics in infants treated with multiple courses of antenatal corticosteroids with those in matched control infants delivered >7 days from dosing and those of matched untreated infants.

STUDY DESIGN

Eighteen infants who received multiple courses of corticosteroids and were delivered within 7 days of dosing were matched with 18 infants who received 1 course of corticosteroids >7 days before delivery (remote) and 18 untreated infants. Respiratory compliance and functional residual capacity were measured within 36 hours. Differences were compared by analysis of variance.

RESULTS

Infant demographics were similar. Respiratory compliance was higher in the multiple-course group than in the remote or untreated group (P <.02). Functional residual capacity was higher in the multiple-course group than in the untreated group (P <.05) but similar to that found in the remote group.

CONCLUSION

Babies delivered after multiple courses of corticosteroids and within 7 days of dosing demonstrated improved respiratory compliance compared with untreated and remotely treated infants. This suggests that the enzyme system responsible for surfactant production can be repetitively induced despite prior treatment with corticosteroids. The increased functional residual capacity in remotely treated infants may reflect a maturation of lung architecture independent of surfactant production.

(+) 3,4-methylenedioxymethamphetamine ('ecstasy') transiently increases striatal 5-HT1B binding sites without altering 5-HT1B mRNA in rat brain

(+) 3,4-Methylenedioxymethamphetamine (MDMA) is a psychedelic drug of abuse that causes selective degeneration of serotonergic fibers of dorsal raphe neurons that project throughout the forebrain. Previous studies using pharmacological and behavioral approaches suggested that MDMA treatment leads to desensitization of 5-HT1B receptors. We proposed to test whether this occurs by downregulation of 5-HT1B messenger RNA in dorsal raphe, striatum or CA1 hippocampal neurons and/or 5-HT1B binding site density in hippocampus and basal ganglia. In Experiment I, rats were treated with MDMA using several dosing protocols (2.5 or 10 mg kg-1 day-1 s.c. given a single time or twice daily for 4 days). The animals were killed 24 h after the last dose. [3H]-citalopram binding to serotonin transporters in hippocampus was reduced in the high dose protocol, indicating degeneration of forebrain serotonergic fibers. Despite the extensive reduction in serotonergic content, 5-HT1B mRNA did not change from control levels in any region when measured by in situ hybridization. [125I]-Iodocyanopindolol binding to 5-HT1B sites in hippocampus was also not changed. In Experiment II, high dose MDMA had no effect on 5-HT1B mRNA in any brain region either 1 or 14 days after treatment. However, [125I]-iodocyanopindolol binding more than doubled in striatum 1 day after MDMA treatment but returned to control levels by 14 days. This may have been a transient compensation to early neuronal damage caused by MDMA exposure. These results suggest that previously described changes in 5-HT1B function following MDMA treatment involve only posttranscriptional changes in receptor regulation and do not alter 5-HT1B mRNA levels.

Prone positioning decreases episodes of hypoxemia in extremely low birth weight infants (1000 grams or less) with chronic lung disease

Extremely low birth weight infants with chronic lung disease (CLD) have frequent episodes of desaturation (hypoxemia). We quantified oxygenation and episodes of hypoxemia in 55 infants (birth weight < or = 1000 gm) with CLD in the supine versus prone position, for 1-hour time intervals. Oxygen saturation was measured with the Nellcor N-200 pulse oximeter and a computer program. Prone positioning increased oxygen saturation from 92.0% to 94.1% (p < 0.001) and significantly decreased episodes of hypoxemia to oxygen saturation levels of less than 90%, 85%, and 80% (p < 0.001). Our findings support prone positioning for the extremely low birth weight infant with CLD in an intensive care setting.

Pulse oximetry in newborn infants with birth weights of 620 to 4285 grams receiving dopamine and dobutamine

The reliability of pulse oximetry in neonates receiving inotropic drugs because of hypotension and microcirculatory perfusion failure has not been well documented. Signal loss of the pulse oximeter in adult patients receiving dopamine infusions has been reported. To evaluate the relationship between pulse oximeter oxygen saturation (SaO2) and co-oximeter directly measured oxygen saturation, we studied 30 infants in the first 4 days of life (birth weight 620 to 4285 gm, gestational age 26 to 43 weeks) receiving dopamine (30 patients) and dobutamine (10 infants). Infants had normal blood pressures at the time of the study. To minimize motion artifact a Nellcor N-200 (Nellcor Incorporated, Hayward, Calif.) oximeter with electrocardiographic synchronization was used. We compared pulse oximeter values with simultaneous arterial samples analyzed for oxygen saturation with an IL 282 co-oximeter (Instrumentation Laboratory, Inc., Lexington, Mass.). The values were corrected for spuriously elevated carboxyhemoglobin levels and fetal hemoglobin level was quantitatively measured. The partial pressure of oxygen at 90% hemoglobin saturation for each patient was calculated. The dosage of dopamine ranged from 4 to 28 micrograms/kg per minute and the dosage of dobutamine varied from 4 to 24 micrograms/kg per minute. Over a wide range of values for mean blood pressure (23 to 66 mm Hg), partial pressure of oxygen at 90% hemoglobin saturation (43.1 to 70.2 mm Hg), and oxygen saturation (SaO2 80% to 100%), linear regression analysis revealed a close correlation between pulse oximeter SaO2 and co-oximeter SaO2 values (r = 0.83, standard error of the estimate 2.2%, p < 0.0001). Our findings indicate that pulse oximetry can be used reliably for continuous oxygen monitoring in normotensive neonates with an SaO2 of 80% to 100% who are receiving dopamine and dobutamine.

Neonatal pulmonary mechanics and oxygenation after prophylactic amnioinfusion in labor: a randomized clinical trial

OBJECTIVE

Amnioinfusion has been reported to improve the perinatal outcome of pregnancies complicated by decreased amniotic fluid volume, but detailed information on its possible adverse effects on neonatal pulmonary mechanics and oxygenation is not available.

STUDY DESIGN

We evaluated 42 infants with birth weights of 2600 to 4320 g and gestational ages of 36 to 44 weeks, who were born to mothers enrolled in a prospective, randomized trial of amnioinfusion for oligohydramnios in labor. Maternal entry criteria were gestational age 36 weeks or older, estimated fetal weight more than 2500 g, oligohydramnios defined as an amniotic fluid index of 5 cm or less, and a normal fetal heart rate pattern. Evaluation of pulmonary mechanics and oxygen saturation (SaO2) was done with the infants breathing room air between birth and day 3 of life. Transpulmonary pressure, flow, and tidal volume were recorded simultaneously, and pulmonary resistance and lung compliance were calculated. SaO2 was measured for 30 minutes with the Nellcor N-200 oximeter and IBM computer oximetry software.

RESULTS

Evaluation of the data revealed no significant difference between the two groups for tidal volume, lung compliance, pulmonary resistance, or work of breathing. There were no differences between the two groups in the number of desaturation episodes or in percent of desaturations to less than 90%, 85%, or 80% SaO2.

CONCLUSION

Prior studies have shown amnioinfusion to improve perinatal outcome. Our findings demonstrate that amnioinfusion for oligohydramnios in labor does not adversely affect neonatal pulmonary mechanics or oxygenation.

Effects of early dexamethasone therapy on pulmonary mechanics and chronic lung disease in very low birth weight infants: a randomized, controlled trial

OBJECTIVE

To determine the changes in pulmonary mechanics before and during early dexamethasone therapy, and to evaluate the effect of dexamethasone on the duration of mechanical ventilation in very low birth weight (VLBW) ventilator-dependent infants at risk for chronic lung disease (CLD).

METHODS

A prospective randomized trial was conducted. Forty-three patients (birth weight 600 to 1500 g, gestational age 24 to 32 weeks) who failed to be weaned from the respirator at 7 to 14 days of age were enrolled; 23 infants received a 7-day course of dexamethasone (0.5 mg/kg/day intravenously for 3 days, 0.25 mg/kg/day for 3 days, and 0.1 mg/kg/day for 1 day), and 20 patients were in the control group. At similar mean airway pressure (MAP) and fractional inspired oxygen concentration (FiO2), respiratory system mechanics were measured before and on days 2, 5, and 7 of the study. Airway pressure, flow and tidal volume (VT) were recorded and only mechanical breaths were analyzed. Respiratory compliance (Crs) and respiratory resistance (Rrs) were calculated by two factor least mean square analysis.

RESULTS

Eighty-three percent of infants in the dexamethasone group and 90% in the control group received surfactant in the first 24 hours of life. There was a significant increase in Crs and VT in the dexamethasone group as compared with the control group (P < .001). No major changes in Rrs were observed. Dexamethasone therapy significantly decreased FiO2 and MAP P < .001) and facilitated successful weaning from mechanical ventilation. In addition to a shorter duration of mechanical ventilation (P < .01), the occurrence of CLD (FiO2 > 0.21 at 36 weeks of corrected gestational age, chest radiograph changes) was significantly decreased in the dexamethasone group (P < .01). Except for a transient increase in blood pressure and serum glucose, there were no significant differences in infection rates, intraventricular hemorrhage, or retinopathy of prematurity. Thirteen patients in the control group received dexamethasone at a later age.

CONCLUSIONS

Our findings indicate that: 1) early dexamethasone therapy in VLBW infants markedly improves respiratory compliance and tidal volume, reduces FiO2 and MAP requirements, and facilitates extubation in these infants; 2) early dexamethasone therapy reduces the duration of mechanical ventilation and decreases CLD (at 28 days and 36 weeks) in a population of VLBW infants largely treated with surfactant.

Acute pancreatitis associated with acute hepatitis A in a young child

Acute hepatitis A infection is an unusual cause of pancreatitis in adults and has not been reported previously in young children. We describe a 4-year-old girl with acute pancreatitis associated with hepatitis A infection.

Episodes of spontaneous desaturations in infants with chronic lung disease at two different levels of oxygenation

The optimal range of pulse oximeter oxygen saturation (SaO2) for infants with chronic lung disease (CLD) has not been well established. We quantified episodes of spontaneous desaturation, at two different ranges of SaO2. For 1 hr each, we alternatively administered inspired O2 concentrations (FiO2) necessary to maintain an SaO2 of 94-96% or 87-91% to 21 patients (mean birth weight, 865 g; gestational age, 27.3 weeks; postnatal age 40.6 days) with CLD (defined by FiO2 > 0.21 at > or = 28 days and radiographic evidence). SaO2 was monitored with the Nellcor N-200 oximeter and analyzed by a computer program (SatMaster). The percentage of time the infants desaturated to levels of SaO2 < 85 and < 80% revealed significantly fewer spontaneous episodes during the hour of higher baseline SaO2 (P < 0.0002). Comparison of episodes of spontaneous desaturation to SaO2 < 80 and < 85%, lasting 0-15, 16-30, 31-45 sec also showed significant differences between the two levels of SaO2. We conclude that when infants with CLD are maintained at a higher SaO2 they probably experience fewer episodes of spontaneous desaturations, because of less alveolar hypoxia. We believe that attempts at weaning the FiO2 should be tempered with the need of maintaining an adequate SaO2. Therefore, prolonged monitoring of oxygenation in infants with CLD at different levels of SaO2 could be helpful during the weaning process.

Spontaneous desaturations in intubated very low birth weight infants with acute and chronic lung disease

Patients with chronic lung disease (CLD) have frequent episodes of spontaneous desaturations. Utilizing computerized pulse oximetry (CPO) we quantified the frequency and severity of spontaneous desaturations in very low birth weight (VLBW) infants with CLD. Thirty-four studies by CPO were performed in intubated infants for 4 hours; 17 patients (birth weight, 550-980 g; postnatal age 28-85 days) had CLD, and 17 (birth weight, 520-980 g; postnatal age, 1-7 days) had acute lung disease. Oxygen saturation (SaO2) was measured with the Nellcor N-200 oximeter, its serial output (updated once a second) captured by a computer. Pulse rate, pulse amplitude, and heart rate were also monitored continuously. We measured respiratory system mechanics in 23 patients. Tidal volume (VT), respiratory system compliance (Crs), and resistance (Rrs) were obtained by the PeDS system. Spontaneous desaturation to SaO2 less than 90% occurred for 4.5% of the time in acute patients vs. 27.1% of the time in chronic patients (P less than 0.0001); to SaO2 less than 85%, 0.7% vs. 7.6% of the time in acute vs. chronic patients (P less than 0.002); and to SaO2 less than 80%, 0.4% vs. 2.6% of the time in acute vs. CLD patients (P less than 0.05). Rrs was significantly higher in the ventilated patients with CLD (174 cmH2O/L/s) than in the ventilated patients with acute lung disease (94 cmH2O/L/s, P less than 0.0001). The mean Crs values of the two groups were comparable. Our preliminary data indicate that VLBW infants with CLD receiving assisted ventilation have a greater number of spontaneous desaturation episodes, as compared to patients with acute lung disease.