Colorimetric end-tidal carbon dioxide detectors in the delivery room: strengths and limitations. A case report

Clinical assessment and end-tidal carbon dioxide (ETCO2) detectors are used to verify tracheal intubation in newborn infants. A case is presented in which an ETCO2 detector was misleading in determining endotracheal tube (ETT) position but useful in determining the efficacy of ventilation in an extremely preterm infant.     

Relationship of the ventilatory response to hypoxia with neonatal apnea in preterm infants

OBJECTIVE: Correlate the ventilatory response of preterm infants to hypoxic exposure with incidence of neonatal apnea.Study design Seventeen stable convalescing premature infants underwent bedside cardiorespiratory monitoring of respiration using respiratory inductance plethysmography, heart rate, and oxygen saturation (SaO(2)) for a 12-hour period. These studies were scored for number of apneas > or =15 and > or =20 seconds. Infants then underwent a 3-minute hypoxic exposure. Minute ventilation (V(E)) was calculated for 30-second epochs from the time inspired oxygen reached 15%. Linear regression analysis was used to correlate the change in V(E) normalized for decrease in SaO(2) (DeltaV(E)/DeltaSaO(2)) during the first and third minutes of hypoxic exposure with the number of apneic episodes during the 12-hour study. RESULTS: The majority of infants exhibited an anticipated biphasic ventilatory response to hypoxia. There was a significant positive correlation between DeltaV(E)/DeltaSaO(2) during the first and third minutes of hypoxic exposure and number of apneic episodes > or =15 and > or =20 seconds during the preceding 12 hours. CONCLUSIONS: Preterm infants with a greater number of apneic episodes exhibit an increased ventilatory response to hypoxic exposure, suggesting that apnea of prematurity may be associated with enhanced peripheral chemoreceptor activity.     

Randomized trial of high-frequency oscillatory ventilation versus conventional ventilation: effect on systemic blood flow in very preterm infants

OBJECTIVE: Low superior vena cava (SVC) flow is common in very preterm infants in the first day and strongly associated with periventricular hemorrhage and disability. We examined the effect of high-frequency oscillatory ventilation (HFOV) compared with conventional ventilation (CV) on SVC flow and right ventricular output. METHODS: Forty-five infants <29 weeks were randomized before 1 hour of age to HFOV or CV. Echocardiography was performed on 43 infants at 3, 10, and 24 hours of age. Infants with low SVC flow (<50 mL/kg/min) or hypotension (mean blood pressure < or =20) were treated with volume and inotrope. RESULTS: Infants allocated to HFOV (n=23) and to CV (n=20) were well matched. There was a nonsignificant trend toward more infants on HFOV having SVC flow <50 mL/kg/min (48% vs 20%) and receiving volume and inotropes (61% vs 40%). There were no significant differences in mean SVC flow or right ventricular output at 3, 10, or 24 hours. Infants on HFOV had a significantly higher calculated upper body vascular resistance at 10 hours and mean blood pressure at 24 hours. CONCLUSIONS: There were no significant adverse effects of HFOV on systemic blood flow in very preterm infants during the first 24 hours of life.     

Growth hormone and body composition in children younger than 2 years with Prader-Willi syndrome

OBJECTIVES: To assess body composition of infants with Prader-Willi syndrome (PWS) by using deuterium dilution and investigating the efficacy of early institution of growth hormone (GH) therapy in increasing lean mass (LM) and preventing massive obesity. STUDY DESIGN: One group of 11 children with PWS <2 years before and during 30-month GH therapy (GH group) was compared with 6 infants administered only coenzyme Q(10) for 1 year (Q10 group). LM adjusted for height (LM(Ht)) and relative fat mass (%FM(Age)) standard deviation scores (SDS) were calculated from data of 95 healthy children. RESULTS: Initially, LM(Ht) of all patients was below the normal average. LM(Ht) decreased by -0.46 +/- 0.3 SD (P=.03) per year in the Q10 group but rose by 0.25 +/- 0.3 SD (P=.02) per year during GH therapy, normalizing after 30 months (-0.70 +/- 1.0 SD). Despite low to normal weight for height (WfH), %FM(Age) was above the normal average (GH group, 31.0% +/- 4.5%, Q10 group, 32.4% +/- 9.5%). In the Q10 infants, %FM(Age) increased by 0.71 +/- 0.7 SD per year, whereas in the GH group, %FM(Age) remained more stable up to 30 months. CONCLUSIONS: Diminished LM(Ht) found in infants with PWS further declines during the early years. Early institution of GH therapy lifts LM(Ht) into the normal range and delays fat tissue accumulation.     

Does bronchodilator responsiveness in infants with bronchiolitis depend on age?

OBJECTIVE: To assess the relation between age and bronchodilator responsiveness in infants with bronchiolitis. STUDY DESIGN: In 41 infants (age, 2 to 18 months) with bronchiolitis, lung function was measured with the raised volume rapid thoracoabdominal compression technique before and after salbutamol inhalation. Lung function was quantified in terms of timed volumes (FEV(0.5), FEV(0.75), and FEV(1.0)). A significant change was defined as a postbronchodilator value that differed from baseline by more than twice the within-subject coefficient of variation. RESULTS: For the group, postbronchodilator values did not differ significantly from baseline (DeltaFEV(0.5), 3.8% +/- 9.3%; DeltaFEV(0.75), 3.5% +/- 9.5%; and DeltaFEV(1.0), 4.0 +/- 9.8%). Eleven subjects showed significantly increased timed volumes; 3 presented with a decreased lung function; the remaining patients failed to show a significant change. The mean age of subjects with improved lung function did not differ significantly from the mean age of those with no or paradoxical responses (9.7 +/- 4.7 vs 8.1 +/- 4.1 months); there was no correlation of age with the size of the bronchodilator response. CONCLUSIONS: The results of the current study indicate that bronchodilator responsiveness in infants with bronchiolitis is not age-dependent.     

Oxygen saturation in healthy infants immediately after birth

OBJECTIVE: Because the optimal concentration of oxygen (FiO2) required for stabilization of the newly born infant has not been established, the FiO2 is commonly adjusted according to the infant's oxygen saturation (SpO2). We aimed to determine the range of pre-ductal SpO2 in the first minutes of life in healthy newborn infants. STUDY DESIGN: We applied an oximetry sensor to the infant's right palm or wrist of term and preterm deliveries immediately after birth. Infants who received any resuscitation or supplemental oxygen were excluded. SpO2 was recorded at 60 second intervals for at least 5 minutes and until the SpO2 was >90%. RESULTS: A total of 205 deliveries were monitored; 30 infants were excluded from the study. SpO2 readings were obtained within 60 seconds of age from 92 of 175 infants (53%). The median (interquartile range) SpO2 at 1 minute was 63% (53%-68%). There was a gradual rise in SpO2 with time, with a median SpO2 at 5 minutes of 90% (79%-91%). CONCLUSION: Many newborns have an SpO2 <90% during the first 5 minutes of life. This should be considered when choosing SpO2 targets for infants treated with supplemental oxygen in the delivery room.     

The safety and efficacy of nitric oxide therapy in premature infants

OBJECTIVES: To assess the safety-efficacy balance of low-dose inhaled nitric oxide (iNO) in hypoxemic premature infants because no sustained beneficial effect has been demonstrated clearly and there are concerns about side effects. STUDY DESIGN: Eight hundred and sixty infants <32 weeks were randomized at birth to receive 5 ppm iNO or placebo when they presented with hypoxemic respiratory failure (HRF) defined by a requirement for mechanical ventilation, fraction of inspired oxygen (FIO 2 ) >40%, and arterio-alveolar ratio in oxygen (aAO 2 ) <0.22. The primary end point was intact survival at 28 days of age. RESULTS: Sixty-one of 415 infants presented with HRF and were compared with 84 of 445 controls who presented with HRF. There was no difference in the primary end point (61.4% in infants [23% with HRF who were treated with iNO] vs 61.1% in controls [21.4% in controls with HRF]; P = .943). For the infants with HRF who were treated with iNO, there was no significant difference from controls for intraventricular hemorrhage (IVH) (6% vs 7%), necrotizing enterocolitis (8% vs 6 %), or patent ductus arteriosus (PDA) (34% vs 37%). Compared with nonhypoxemic infants, the risk of bronchopulmonary displasia (BPD) increased significantly in HRF controls (OR = 3.264 [CI 1.461-7.292]) but not in infants with HRF who were treated with iNO (OR = 1.626 [CI 0.633-4.178]). CONCLUSIONS: iNO appears to be safe in premature infants but did not lead to a significant improvement in intact survival on day 28.     

Mechanical ventilation of very low birth weight infants: is volume or pressure a better target variable?

OBJECTIVE: To compare the efficacy and safety of volume-controlled (VC) ventilation to time-cycled pressure-limited (TCPL) ventilation in very low birth weight infants with respiratory distress syndrome (RDS). STUDY DESIGN: Newborns weighing between 600 and 1500 g and with a gestational age of 24 to 31 weeks who had RDS were randomized to receive either VC or TCPL ventilation and treated with a standardized protocol. The 2 modalities were compared by determining the time required to achieve a predetermined success criterion, on the basis of either the alveolar-arterial oxygen gradient <100 mm Hg or the mean airway pressure <8 cm H(2)O. Secondary outcomes included mortality, duration of mechanical ventilation, and complications commonly associated with ventilation. RESULTS: The mean time to reach the success criterion was 23 hours in the VC group versus 33 hours in the TCPL group (P = .15). This difference was more striking in babies weighing <1000g (21 versus 58 hours; P = .03). Mean duration of ventilation with VC was 255 hours versus 327 hours with TCPL (P = .60). There were 5 deaths in the VC group and 10 deaths in the TCPL group (P = .10). The incidence of other complications was similar. CONCLUSION: VC ventilation is safe and efficacious in very low birth weight infants and may have advantages when compared with TCPL, especially in smaller infants.     

Bradycardia and desaturation during skin-to-skin care: no relationship to hyperthermia

OBJECTIVE: We recently found increased temperature and increased bradycardia and desaturation during skin-to-skin care (SSC). We wanted to determine if these effects were related. STUDY DESIGN: Twenty-two infants (median gestational age at birth 28.5 weeks [range 24-31], median age at study 25.5 days [range 10-60 days], median birth weight 1025 g [range 550-1525 g], median weight at study 1320 g [range 900-2460 g]) underwent three 2-hour recordings of breathing movements, nasal airflow, heart rate, and pulse oximeter saturation (SpO 2 ): at thermoneutrality (TN) during incubator care, at TN during SSC, and at elevated temperature (ET) during incubator care. Core temperature was measured via a rectal probe. Recordings were analyzed for the summed rate of bradycardia and desaturation (heart rate <2/3 of baseline; SpO 2 相似文献   

Oxygen saturation as a predictor of prolonged, frequent bronchodilator therapy in children with acute asthma

OBJECTIVES: To examine if the initial oxygen saturation (SaO2) in the Emergency Department is a useful predictor of prolonged frequent bronchodilator therapy (FBT) in children with acute asthma. STUDY DESIGN: Prospective cohort study of 273 children, 1 to 17 years of age, requiring systemic corticosteroids. Patients were categorized as needing FBT for >4 hours (n=166) versus >4 hours (n=107) and >12 hours (n=79) versus >12 hours (n=194). Multiple logistic regression determined the association between SaO2 and these outcomes. RESULTS: Baseline SaO2 remains a significant independent predictor of FBT for >4 hours (OR=0.81) and >12 hours (OR=0.84); 91% of patients with SaO2 of 90% to 91% had FBT >4 hours and 80% of patients with SaO2 of < or =89% had FBT >12 hours. Children with SaO2 of < or =91% are 14.7 and 12.0 times more likely to require FBT for >4 hours and >12 hours, respectively, than those with SaO2 of 98% to 100%. The interval likelihood ratios for FBT >4 hours were 12.3 for SaO2 of < or =89%, 6.5 for 90% to 91%, but only 1.8 for 92% to 93%. The likelihood ratios for FBT >12 hours decreased from 9.8 for SaO2 of < or =89% to 3.5 for SaO2 of 90% to 91%. CONCLUSIONS: SaO2 is a useful predictor of FBT >4 hours if it is < or =91% and of FBT >12 hours if it is < or =89%.     

Noninvasive therapy with helium-oxygen for severe bronchiolitis

OBJECTIVE: To determine whether noninvasive therapy using a helium-oxygen mixture reduces the use of positive-pressure ventilation in the treatment of respiratory failure caused by severe bronchiolitis. STUDY DESIGN: This was a multicenter, randomized, double-blind, placebo-controlled trial that recruited infants in 4 pediatric intensive care units (PICUs). A total of 39 nonintubated infants with severe bronchiolitis caused by respiratory syncytial virus (RSV) were randomly assigned within 8 hours of PICU admission to receive a helium-oxygen mixture (helium group) or an air-oxygen mixture (control group) through an inflatable head hood. The primary study outcome was the requirement for positive pressure mechanical ventilation. Results were compared using Fisher's exact test. RESULTS: No differences were noted between the control and helium groups with respect to age (1.0 vs 1.1 months), prematurity, or family history of asthma or smoking. Positive pressure ventilation was judged necessary for 4 of the 21 (19.0%) infants in the control group and in 4 of the 18 (22.2%) in the helium group (relative risk = 1.17; 95% confidence interval = 0.34 to 4.01). CONCLUSIONS: This study did not detect any differences between the patients in the helium group and the control group with respect to the rate of positive-pressure ventilation.     

Surfactant phosphatidylcholine metabolism in neonates with meconium aspiration syndrome

OBJECTIVE: Because meconium directly inhibits surfactant function, we sought to determine the effect of meconium on endogenous surfactant synthesis and clearance. STUDY DESIGN: We studied surfactant phosphatidylcholine kinetics with the use of stable isotopes in 11 newborn infants with meconium aspiration syndrome (MAS) who required extracorporeal membrane oxygenation (ECMO). For comparison we studied 6 neonates with persistent pulmonary hypertension (PPHN) on ECMO and 10 term neonates ventilated for non-pulmonary indications and not on ECMO. All patients received a 24-hour [U- 13C]glucose infusion as precursor for the palmitic acid in surfactant phosphatidylcholine. RESULTS: In the meconium group, the maximal 13C-incorporation in phosphatidylcholine (PC) was half of that in controls (0.09 +/- 0.01 vs 0.18 +/- 0.03 atom percent excess [APE], P = .027). There was a trend toward lower surfactant synthesis in the MAS group (3.3 +/- 0.7%/day) and PPHN group (2.6 +/- 0.3%/day) compared with controls 8.0 +/- 2.4%/day, P = .058). Significantly lower PC concentrations in tracheal aspirates were found in the MAS group (4.4 +/- 2.6 mg/mL) and PPHN group (3.6 +/- 2.0 mg/mL) compared with controls (12.8 +/- 2.6 mg/mL, P = .01). Endogenously synthesized surfactant had a similar half-life in all groups, ranging from 63 to 98 hours. CONCLUSION: We conclude that surfactant synthesis is disturbed and that surfactant PC concentrations are low in infants with MAS on ECMO.     

Variables associated with the early failure of nasal CPAP in very low birth weight infants

OBJECTIVE: To identify risk factors and neonatal outcomes associated with the early failure of "bubble" nasal continuous positive airway pressure (CPAP) in very low birth weight (VLBW) infants with respiratory distress syndrome (RDS). STUDY DESIGN: Following resuscitation and stabilization at delivery, a cohort of 261 consecutively inborn infants (birth weight < or = 1250 g) was divided into three groups based on the initial respiratory support modality and outcome at 72 hours of age: "ventilator-started" group, "CPAP-failure" group, and "CPAP-success" group. RESULTS: CPAP was successful in 76% of infants < or = 1250 g birth weight and 50% of infants < or = 750 g birth weight. In analyses adjusted for postmenstrual age (PMA) and small for gestational age (SGA), CPAP failure was associated with need for positive pressure ventilation (PPV) at delivery, alveolar-arterial oxygen tension gradient (A-a DO2) >180 mmHg on the first arterial blood gas (ABG), and severe RDS on the initial chest x-ray (adjusted odds ratio [95% CI] = 2.37 [1.02, 5.52], 2.91 [1.30, 6.55] and 6.42 [2.75, 15.0], respectively). The positive predictive value of these variables ranged from 43% to 55%. In analyses adjusted for PMA and severe RDS, rates of mortality and common premature morbidities were higher in the CPAP-failure group than in the CPAP-success group. CONCLUSION: Although several variables available near birth were strongly associated with early CPAP failure, they proved weak predictors of failure. A prospective controlled trial is needed to determine if extremely premature spontaneously breathing infants are better served by initial management with CPAP or mechanical ventilation.     

Lifestyle-only intervention attenuates the inflammatory state associated with obesity: a randomized controlled study in adolescents

OBJECTIVES: The primary goals were to understand the relationship among the inflammatory factors, C-reactive protein (CRP), interleukin-6 (IL-6), and fibrinogen, and indices of obesity in normoglycemic, insulin-resistant adolescents and to investigate the impact of a lifestyle-only intervention on these nontraditional risk factors for cardiovascular disease (CVD). STUDY DESIGN: Randomized controlled lifestyle-only intervention study in adolescents. Of the 21 adolescents studied, 15 obese subjects (body mass index [BMI] = 37.6 +/- 3.3 kg/m 2 ) were randomized to either a lifestyle intervention program or usual care. The lean controls were studied only at baseline. Analysis of variance (ANOVA) for repeated measures was used to study intervention effect and t test, one-way ANOVA, and discriminant function analysis for baseline comparisons. RESULTS: The intervention group maintained weight, whereas the control group gained weight (P = .02). A redistribution of body composition and a decrease in insulin resistance were observed. Elevated circulating concentrations of CRP, fibrinogen, and IL-6 were significantly reduced (all P 相似文献   

Prenatal tobacco exposure influences cerebral oxygenation in preterm infants

Aim

Our aim was to determine the influence of prenatal tobacco exposure on regional cerebral tissue oxygen saturation (r_cSO₂) and fractional tissue oxygen extraction (FTOE) in preterm infants. We hypothesized that as a result of vasoconstriction caused by prenatal tobacco exposure r_cSO₂ would be lower and FTOE would be higher during the first days after birth in infants exposed to tobacco during pregnancy.

Methods

Sixty preterms were included in this prospective, observational cohort study (median gestational age 29.9 weeks, range 26.0-31.8, median birth weight 1248 g, range 615-2250). Fourteen infants had been exposed to tobacco during pregnancy. All mothers smoked more than five cigarettes a day till delivery. We measured r_cSO₂ and transcutaneous arterial oxygen saturation (tcSaO₂) in all infants on days 1-5, 8, and 15. FTOE was calculated: FTOE = (tcSaO₂ − r_cSO₂) / tcSaO₂.

Results

In preterm infants exposed to tobacco during pregnancy, r_cSO₂ was lower during days 1, 2, and 8 after birth, median 73% versus 81%, 73% versus 80% and 71% versus 78% respectively. FTOE was higher during days 1 and 8 after birth, median 0.24 versus 0.15 and 0.26 versus 0.19 respectively. On the second day, FTOE tended to be higher, 0.18 versus 0.14.

Conclusions

During the first two days and day 8 after birth cerebral oxygen saturation is lower and oxygen extraction higher in preterm infants following prenatal tobacco exposure. Our data suggest that prenatal tobacco exposure may have an effect on cerebral oxygenation of the infant.     

Cardiopulmonary fitness and muscle strength in patients with osteogenesis imperfecta type I

OBJECTIVE: To evaluate cardiopulmonary function, muscle strength, and cardiopulmonary fitness (VO 2 peak) in patients with osteogenesis imperfecta (OI). STUDY DESIGN: In 17 patients with OI type I (mean age 13.3 +/- 3.9 years) cardiopulmonary function was assessed at rest using spirometry, plethysmography, electrocardiography, and echocardiography. Exercise capacity was measured using a maximal exercise test on a bicycle ergometer and an expired gas analysis system. Muscle strength in shoulder abductors, hip flexors, ankle dorsal flexor, and grip strength were measured. All results were compared with reference values. RESULTS: Cardiopulmonary function at rest was within normal ranges, but when it was compared with normal height for age and sex, vital capacities were reduced. Mean absolute and relative VO 2 peak were respectively -1.17 (+/- 0.67) and -1.41 (+/- 1.52) standard deviations lower compared with reference values ( P < .01). Muscle strength also was significantly reduced in patients with OI, ranging from -1.24 +/- 1.40 to -2.88 +/- 2.67 standard deviations lower compared with reference values. CONCLUSIONS: In patients with OI type I, no pulmonary or cardiac abnormalities at rest were found. The exercise tolerance and muscle strength were significantly reduced in patients with OI, which might account for their increased levels of fatigue during activities of daily living.     

Sleep-disordered breathing in Prader-Willi syndrome and its association with neurobehavioral abnormalities

OBJECTIVES: To determine the prevalence and type of sleep-disordered breathing among patients with Prader-Willi syndrome (PWS) and its relationship to such neurobehavioral abnormalities as mental retardation, obsessive-compulsive behavior, and conduct disorders. STUDY DESIGN: Polysomnography (PSG) studies were conducted in 13 unselected subjects with PWS (age 1.5 to 28 years). PSG results were compared with tests of behavior and cognition (Development Behavior Checklist [DBC], Auditory Continuous Performance Test [ACPT], and Wechsler Intelligence Scale appropriate for age). RESULTS: Nine of 13 (69%) subjects had > 10 apneas and hypopneas per hour of sleep. Apart from a 2-year-old subject with normal body weight who demonstrated severe central hypopnea in rapid eye movement sleep, the sleep-breathing disturbance was due to upper airway obstruction. Age-adjusted body mass index was associated with more severe hypoxemia during sleep (min SaO2, r = -.87, P < .005) and more sleep disruption (arousals/hour of sleep, r = .62, P < .05; sleep efficiency, r = -.66, P < .05). Increasing severity of obstructive sleep apnea (OSA) or sleep disturbance was associated with daytime inactivity/sleepiness and autistic-relating behavior (DBC) and with impulsiveness (ACPT). Unexpectedly, sleep hypoxemia appeared to be predictive of increased performance IQ. CONCLUSIONS: OSA is prevalent among subjects with PWS and is associated with increased body mass, daytime inactivity/ sleepiness, and some behavioral disturbances.