The use of electrical cardiometry for continuous cardiac output monitoring in preterm neonates: a validation study.

BACKGROUND: Electrical cardiometry (EC) is a continuous noninvasive method for measuring cardiac output (CO), but there are limited data on premature infants. We evaluated the utility of EC monitoring by comparing the results obtained using EC to measurements of CO and systemic blood flow using echocardiography (ECHO). METHODS: In this prospective observational study, 40 preterm neonates underwent 108-paired EC and ECHO measurements. RESULTS: There were correlations between EC-CO and left ventricular output (LVO, p < 0.005) and right ventricular output (RVO, p < 0.005) but not with superior vena cava (r = 0.093, p = 0.177). Both RVO and LVO correlated with EC with and without a hemodynamically significant ductus arteriosus (p = 0.001 and 0.008, respectively). The level of agreement was decreased in infants ventilated by high-frequency oscillation ventilators (HFOV). The bias in HFOV was also positive compared with the negative biases found in other modes of ventilation. CONCLUSION: Given the correlation of EC with LVO, RVO, and lack of confounding effects of the ductus, our results suggest that EC has promise for trending CO in the preterm infant. However, given the limitations with mode of ventilation and the lack of correlation at low LVO values, further study is needed before this technology can be for routine use.

Early prediction of a significant patent ductus arteriosus in infants <32 weeks gestational age.

BACKGROUND: The optimal thresholds for identification of preterm infants at greatest risk for adverse sequelae related to patent ductus arteriosus have not been well delineated. Our aim was to determine hemodynamic parameters in the first 24 hours using continuous non-invasive vital and structural measurements to predict which infants required PDA treatment in our institution. METHODS: Retrospective secondary analysis of data from infants born 23 to 32 weeks gestational age with cardiac output and stroke volume via electrical cardiometry, cerebral tissue oximetry measurements, mean arterial blood pressure (BP), heart rate, and oxygen saturation and functional echocardiography results at 12 hours of life were recorded when available (93 percent of subjects). RESULTS: A total of 292 infants, of which 55 (26±2 weeks, 862±268 grams) were treated for PDA. Treated infants demonstrated increased left ventricular output (p < 0.001) and lower mean BP (p = 0.010). The optimal area under the receiver operating characteristic curve (AUC) for predicting PDA treatment in our all gestations cohort is a mean BP at 15 hours of life of <33 mm Hg (AUC = 0.854, p < 0.001, 95% CI 0.792, 0.916). For infants <28 weeks a mean BP at 13 hours of life of <33 mm Hg (AUC = 0.741, p < 0.050, 95% CI 0.642, 0.839). CONCLUSIONS: In our cohort increased left ventricular output and lower mean BP predicted a clinically significant PDA requiring treatment.

Inhaled nitric oxide for respiratory failure in preterm infants.

BACKGROUND: Inhaled nitric oxide (iNO) has been proven to be effective in term infants with hypoxic respiratory failure. The pathophysiology of respiratory failure, and the potential risks, differ substantially in preterm infants. Therefore, analysis of the efficacy and toxicities of iNO in infants born before 35 weeks is necessary. OBJECTIVES: To determine the effect of treatment with iNO on the rates of death, bronchopulmonary dysplasia (BPD), intraventricular haemorrhage (IVH), or neurodevelopmental disability in preterm newborn infants (< 35 weeks gestation) with respiratory disease. SEARCH STRATEGY: Standard methods of the Cochrane Neonatal Review Group were used. MEDLINE, EMBASE, Healthstar and the Cochrane Central Register of Controlled Trials (CENTRAL, The Cochrane Library) were searched, using the following keywords: nitric oxide, clinical trial, and newborn covering the years from 1985 to 2006. In addition, the abstracts of the Pediatric Academic Societies were also searched. SELECTION CRITERIA: Randomised and quasi-randomised studies in preterm infants with respiratory disease that compared the effects of administration of iNO gas compared to control, with or without placebo are included in this review. DATA COLLECTION AND ANALYSIS: Data regarding clinical outcomes including death, BPD (defined as oxygen dependence at 36 weeks postmenstrual age), IVH, periventricular leukomalacia (PVL), long term neurodevelopmental outcome and short term effects on oxygenation were excerpted from the trial reports by the investigators. Standard methods of the Cochrane Neonatal Review Group were used. Two investigators extracted, assessed and coded separately all data for each study. Any disagreement was resolved by discussion. MAIN RESULTS: Eleven randomised controlled trials of inhaled nitric oxide therapy in preterm infants were found. The trials have been grouped post hoc into three categories depending on the entry criteria; entry in the first three days of life based on oxygenation criteria (Kinsella 1999; Hascoet 2004; INNOVO 2005; Van Meurs 2004; Mercier 1999; Dani 2006), routine use in intubated preterm babies (Schreiber 2003; Kinsella 2006) and later enrolment based on an increased risk of BPD (Subhedar 1997; Ballard 2006). The usefulness of the overall analyses was considered limited by the differing characteristics of the studies, and only subgroup analyses were performed. Trials of early rescue treatment of infants based on oxygenation criteria demonstrated no significant effect of iNO on mortality or BPD. The subgroup of studies with routine use of iNO in intubated preterm infants demonstrated a marginally significant reduction in the combined outcome of death or BPD [typical RR 0.91 (95% CI 0.84, 0.99); typical RD -0.06 (95% CI -0.12, -0.01)]. Later treatment with iNO based on the risk of BPD demonstrated no significant benefit for this outcome in our analysis. Studies of early rescue treatment with iNO demonstrated a trend toward increased risk of severe IVH, whereas the subgroup of studies with routine use in intubated preterm infants seems to show a reduction in the risk of having either a severe IVH or PVL [typical RR 0.70 (95% CI 0.53, 0.91); typical RD -0.07 (95% CI -0.12, -0.02)]. Later iNO treatment of infants at risk of BPD is given after the major risk period for IVH, and does not appear to lead to progression of old lesions. Two studies (Schreiber 2003; INNOVO 2005) presented data on long term neurodevelopmental outcome. The early routine treatment study (Schreiber 2003) showed an improved outcome at two years corrected age, while the rescue treatment study (INNOVO 2005) showed no effect of iNO. AUTHORS' CONCLUSIONS: iNO as rescue therapy for the very ill ventilated preterm infant does not appear to be effective and may increase the risk of severe IVH. Later use of iNO to prevent BPD also does not appear to be effective. Early routine use of iNO in mildly sick preterm infants may decrease serious brain injury and may improve survival without BPD. Further studies are needed to confirm these findings, to define groups most likely to benefit, and to describe long term outcomes.

Effects of delivery room quality improvement on premature infant outcomes.

OBJECTIVE: Delivery room management interventions have been successfully implemented via collaborative quality improvement (QI) projects. However, it is unknown whether these successes translate to reductions in neonatal morbidity and mortality. STUDY DESIGN: This was a prospective pre-post intervention study of three nonrandomized hospital groups within the California Perinatal Quality Care Collaborative. A collaborative QI model (Collaborative QI) was compared with a single-site QI model (NICU QI) and a non-participant population when implementing evidence-based delivery room practices. The intervention period was between June 2011 and May 2012. Infants born with gestational age between 22 weeks 0 days and 29 weeks 6 days and birth weight ⩽1500 g were included. Outcomes were mortality and select morbidities (bronchopulmonary dysplasia (BPD), intraventricular hemorrhage (IVH), retinopathy of prematurity (ROP) and necrotizing enterocolitis (NEC)). Outcomes were compared between the baseline (January 2010 to May 2011) and post-intervention period (June 2012 to May 2013) within each comparison group. RESULTS: Ninety-five hospitals were included with 4222 infants in the baseline period and 4186 infants in the post-intervention period. The Collaborative QI group had significantly reduced odds of developing BPD post-intervention (odds ratio (OR) 0.8, 95% confidence interval (CI) 0.65 to 0.99) or composite BPD-death (OR 0.83, 95% CI 0.69 to 1.00). In both the Collaborative QI and non-participants there were also reductions in IVH, severe IVH, composite severe IVH-death, severe ROP and composite severe ROP-death. CONCLUSION: Hospitals dedicated to improving delivery room practices can impact neonatal outcomes.

Nitric oxide for respiratory failure in infants born at or near term.

BACKGROUND: Nitric oxide is a major endogenous regulator of vascular tone. Inhaled nitric oxide gas has been investigated as a treatment for persistent pulmonary hypertension of the newborn. OBJECTIVES: To determine whether treatment of hypoxaemic term and near-term newborn infants with inhaled nitric oxide (iNO) improves oxygenation and reduces the rates of death, the requirement for extracorporeal membrane oxygenation (ECMO), or affects long term neurodevelopmental outcomes. SEARCH STRATEGY: Electronic and hand searching of pediatric/neonatal literature and personal data files. In addition we contacted the principal investigators of articles which have been published as abstracts to ascertain the necessary information. SELECTION CRITERIA: Randomized and quasi-randomized studies of inhaled nitric oxide in term and near term infants with hypoxic respiratory failure. Clinically relevant outcomes, including death, requirement for ECMO, and oxygenation. DATA COLLECTION AND ANALYSIS: Trial reports were analysed for methodologic quality using the criteria of the Cochrane Neonatal Review Group. Results of mortality, oxygenation, short term clinical outcomes (particularly need for ECMO), and long term developmental outcomes were tabulated. STATISTICS: For categorical outcomes, typical estimates for relative risk and risk difference were calculated. For continuous variables, typical estimates for weighted mean difference were calculated. 95% confidence intervals were used. A fixed effect model was assumed for meta-analysis. MAIN RESULTS: Fourteen eligible randomized controlled studies were found in term and near term infants with hypoxia. Seven of the trials compared iNO to control (placebo or standard care without iNO) in infants with moderate or severe severity of illness scores. Four of the trials compared iNO to control, but allowed back up treatment with iNO if the infants continued to satisfy the same criteria for severity of illness after a defined period of time. Two trials enrolled infants with moderate severity of illness score (OI or AaDO2) and randomized to immediate iNO treatment or iNO treatment only if they deteriorated to more severe criteria. One trial studied only infants with congenital diaphragmatic hernia (Ninos 1997), and one trial enrolled both preterm and term infants (Mercier 1998), but reported the majority of the results separately for the two groups. Inhaled nitric oxide appears to improve outcome in hypoxaemic term and near term infants by reducing the incidence of the combined endpoint of death or need for ECMO. The reduction seems to be entirely a reduction in need for ECMO; mortality is not reduced. Oxygenation improves in approximately 50% of infants receiving nitric oxide. The Oxygenation Index decreases by a (weighted) mean of 15.1 within 30 to 60 minutes after commencing therapy and PaO2 increases by a mean of 53 mmHg. Whether infants have clear echocardiographic evidence of persistent pulmonary hypertension of the newborn (PPHN) or not does not appear to affect outcome. The outcome of infants with diaphragmatic hernia was not improved; indeed there is a suggestion that outcome was slightly worsened. The incidence of disability, incidence of deafness and infant development scores are all similar between tested survivors who received nitric oxide or not. AUTHORS' CONCLUSIONS: On the evidence presently available, it appears reasonable to use inhaled nitric oxide in an initial concentration of 20 ppm for term and near term infants with hypoxic respiratory failure who do not have a diaphragmatic hernia.

Inhaled nitric oxide for respiratory failure in preterm infants.

BACKGROUND: Inhaled nitric oxide has been proven effective in term infants with hypoxic respiratory failure. The pathophysiology of respiratory failure, and the potential risks, differ substantially in preterm infants. Analysis of the efficacy and toxicities of inhaled nitric oxide in infants born before 35 weeks is therefore necessary. OBJECTIVES: To determine whether, in preterm newborn infants (< 35 weeks gestation) who have hypoxic respiratory failure, treatment with inhaled nitric oxide improves oxygenation within 2 hours and reduces the rates of death, bronchopulmonary dysplasia, intraventricular haemorrhage, or neurodevelopmental disability SEARCH STRATEGY: Standard methods of the Cochrane Neonatal Review Group were used. We searched MEDLINE, EMBASE, Healthstar and the Cochrane Central Register of Controlled Trials (CENTRAL, The Cochrane Library), using the following keywords: nitric oxide, clinical trial, newborn, and covering years from 1985 to 2005. In addition, we searched the abstracts of the Pediatric Academic Societies. SELECTION CRITERIA: Randomised and quasi randomised studies in preterm infants with hypoxic respiratory failure. Administration of inhaled nitric oxide compared to control with or without placebo. Clinically relevant outcomes that were analysed included death, bronchopulmonary dysplasia (defined as oxygen dependence at 36 weeks postconceptional age), intraventricular haemorrhage, long term neurodevelopmental outcome and short term effects on oxygenation. DATA COLLECTION AND ANALYSIS: Standard methods of the Cochrane Neonatal Review Group were used. Two investigators extracted, assessed and coded separately all data for each study. Any disagreement was resolved by discussion. MAIN RESULTS: Seven randomised controlled trials of inhaled nitric oxide therapy in preterm infants were found. One study consisted of infants determined to have a high risk of developing bronchopulmonary dysplasia (Subhedar 1997). One study studied routine use of inhaled NO in all ventilated preterm infants (Schreiber 2003). The remaining studies consisted of infants with high predicted mortality based on poor oxygenation (Kinsella 1999; Hascoet 2005; INNOVO 2005; Van Meurs 2005; Mercier 1999). No significant effect of inhaled nitric oxide on mortality or bronchopulmonary dysplasia was demonstrated. There was no evidence of effect on the risk of intraventricular haemorrhage. There may be short term improvements in oxygenation. Two studies (Schreiber 2003; INNOVO 2005) have so far presented data on long term neurodevelopmental outcome, one of which demonstrated improved outcome at two years corrected age. AUTHORS' CONCLUSIONS: The currently published evidence from randomised trials does not support the use of inhaled nitric oxide in preterm infants with hypoxic respiratory failure. Further studies may need to be performed to evaluate the potential benefit of routine use of this therapy in infants with milder forms of respiratory failure, and these trials will need to be designed to evaluate not only neonatal survival, and the occurrence of neonatal morbidities, but should be powered to evaluate neurodevelopmental outcome at a minimum of two years of age.

Chest physiotherapy in the neonate: a controlled study.

The effect of postural drainage alone was compared to postural drainage with chest percussions on the arterial blood gases of 20 neonates with respiratory distress. There was no significant alteration in the arterial PO2 following postural drainage alone, with a significant increase (14.5 mm Hg) following postural drainage with chest percussions. The PO2 midway through postural drainage with percussions showed a small (5 mm Hg) but nonsignificant rise in the PO2, suggesting a gradual improvement throughout the use of this form of therapy. There was no significant change in the pH or PCO2 with either procedure. Appropriately performed chest percussions will result in an improvement in oxygenation in neonates with respiratory distress.

Controlled evaluation of muscle relaxation in the ventilated neonate.

To assess the effects of muscle relaxation on the critically ill ventilated neonate, pancuronium bromide was administered for a 12-hour period to ten low-birth-weight neonates (960 to 2,000 gm) of 26 to 34 weeks gestation, all whom required mechanical ventilation and were studied within 48 hours of birth (six to 39 hours). The infants were also studied for a 12-hour period during which no pancuronium bromide was administered. During both study periods, the order of which was randomized, heart rate, blood pressure, PO2, and intracranial pressure were continuously measured. The amounts of handling during the pancuronium and control periods were similar. The results revealed a significantly greater duration of hypoxia (PO2 less than 50 torr) (56.1 vs 23.6 minutes, P less than .001) and hyperoxia (PO2 greater than 70 torr) during the control period (92.5 vs 13 minutes, P less than .001). Durations of intracranial pressure elevation 10 cm H2O above the infant's baseline were significantly less during paralysis (6.7 vs 58.8 minutes, P less than .001) as were spikes of intracranial pressure to greater than 25 cm H2O (1.6 vs 24.4, P less than .05). There was no significant improvement in blood gas values, fractional inspiratory oxygen, or ventilator settings during muscle relaxation. Pancuronium reduced periods of nonoptimal oxygenation and elevated intracranial pressure and may therefore help to decrease adverse sequelae for the low-birth-weight, ventilated neonate.

Neonatal data base and automated discharge summary using a personal computer and proprietary software.

A computerized neonatal data base and a program to develop automated neonatal discharge summaries were developed using a personal computer and proprietary software. The system has been relatively inexpensive, simple to operate, and easy to expand. The current program can produce a discharge summary in less than five minutes, as well as provide detailed summary statistics regarding patients admitted to the intensive care facility. The personal computer and proprietary software are a cost-effective mechanism of improving efficiency in obtaining neonatal statistics and discharge summaries.

Changing attitudes and practices regarding local analgesia for newborn circumcision.

STUDY OBJECTIVE: To change physician attitudes and practices regarding the routine use of local and regional anesthesia for newborn circumcision. DESIGN: Interventional study, followed by an audit of physician practice over a 1-month period, 1 year following interventions. SETTING: The newborn nurseries of the Women's Pavilion, Royal Alexandra Hospital, Edmonton. INTERVENTIONS: A broad range of awareness and educational programs were directed at physicians who perform newborn circumcisions, including posters, newsletters, presentations at grand rounds, video recordings, and practical "hands-on" demonstration of the techniques of local anesthesia to the prepuce and dorsal penile nerve block. RESULTS: Only one physician was using local analgesia for newborn circumcision prior to the introduction of the educational program. The audit, performed 12 months later, documented 46 circumcisions performed by 22 physicians, each performing between 1 and 6 circumcisions (median = 1). Sixteen of the 22 physicians (73%) used either local anesthesia to the prepuce (19 cases) or dorsal penile nerve block (13 cases) during circumcisions. Thus, local analgesia was used in 66% (32/48) of all circumcisions. Six physicians, performing 16 circumcisions, do not use any form of analgesia. CONCLUSIONS: This simple educational program has been associated with a remarkable change in attitudes and practice regarding local analgesia for neonatal circumcision. Our ideal objective, which we hope to achieve through repeated education and practical demonstrations of the techniques to interested physicians, is that all newborn circumcisions are performed under local or regional anesthesia in our institution.

Prolonged periodic breathing: significance in sleep studies.

Periodic breathing (PB) is a pattern of breathing that is frequently recognized in infants being studied for possible sleep apnea. Infants presenting to a sleep laboratory over a 3 1/2-year period who had evidence on their initial study of prolonged (greater than 15% of total sleep time) PB were prospectively studied in an effort to determine the significance of this pattern of breathing. Of the 331 infants studied, 40 demonstrated prolonged PB. Sixteen of these infants, who were of 37 weeks' gestation or greater at birth and did not receive pharmacologic therapy, were studied on at least two occasions (group 1). Of the remaining 24 infants, 11 were treated with methylxanthines by their attending physician (group 2), and 13 did not return for sequential studies (group 3). All infants who were of less than 37 weeks' gestation at birth were separately evaluated (group 4). For group 1, who were studied at a mean age of 15 postnatal weeks, there was a mean of 36.4% periodicity which decreased on the second study to 18.0%. By the fourth study, this had decreased to 9.2%. In group 2, there was a mean of 41.3% periodicity during the first study which decreased to 6.4% on the second study. Infants of group 3 had a mean of 31.4% PB on their initial study and the premature infants, group 4, had 30.1% PB. All infants showed a decrease in PB with sequential studies and no infant was known to have died of sudden infant death syndrome or any other disorder in the first year of life.(ABSTRACT TRUNCATED AT 250 WORDS)

Neonatal apnea: diagnosis by nurse versus computer.

In an effort to characterize significant neonatal apnea and evaluate the nursing diagnosis of apnea, apnea type and frequency were determined in 27 infants by continuous computer recording of heart rate, respiratory impedance, end-tidal CO2, and either or both transcutaneous oxygen and pulse oximetry. Of the 1,266 recorded apneas, 46% were central, 44% were mixed, and 10% were obstructive. Mixed apnea was associated with a longer mean duration and greater mean decrease in heart rate than central apnea. Apnea duration was positively correlated with both a decrease in heart rate and oxygen saturation (P less than .001), and a lower baseline saturation was associated with a greater decrease in oxygen saturation during apnea (P = .002). Theophylline therapy had no effect on apnea duration or oxygen desaturation but resulted in a decrease in the mean heart rate decrease associated with apnea. Overall, nurses diagnosed 54% of all apneic episodes and were significantly poorer at detecting mixed and obstructive events. Nursing detection of apnea improved with increasing apnea duration and was always associated with a greater decrease in heart rate. Nurses diagnosed significantly fewer mixed apnea following theophylline therapy. Improved monitoring techniques, particularly for mixed and obstructive apnea, are essential to increase apnea detection in the nursery.

Vitamin E and necrotizing enterocolitis.

Although vitamin E has been shown to reduce the incidence of severe sequelae from retrolental fibroplasia, there have been recent suggestions that its use may be associated with an increased incidence of necrotizing enterocolitis (NEC). A review was made of experience with vitamin E, both intramuscular and oral, and NEC over a 4 1/2-year period. Of 418 infants of birth weight less than 1,500 g admitted during this period, 28/209 infants who had received vitamin E had definite NEC (13.4%) compared with 12/209 who had not received vitamin E (5.74%, chi 2 = 7.07, P = .008). For infants of birth weight less than 1,250 g, 16/103 infants who received vitamin E developed NEC v 1/159 who had not (chi 2 = 21.1, P less than .001); the incidence of NEC was not significantly different between the two groups for infants with birth weight between 1,250 to 1,500 g. The early mortality (less than seven days) for infants with birth weight of 1,500 g or less was significantly greater for those who had not received vitamin E (43.5% v 13.8%, chi 2 = 44.9, P less than .001), most probably a reflection of the omission of this drug for the most critically ill infants in this retrospective review. The incidence of NEC was not different for infants with birth weight of 1,500 g or less who received intramuscular vitamin E compared with control infants from the same period. For those infants for whom serum tocopherol levels were available, no infant who developed NEC and who had received only oral vitamin E had a serum tocopherol levels of greater than 3.5 mg/100 mL.(ABSTRACT TRUNCATED AT 250 WORDS)

Effects of alterations of inspiratory and expiratory pressures and inspiratory/expiratory ratios on mean airway pressure, blood gases, and intracranial pressure.

Twenty neonates requiring mechanical ventilation for respiratory failure, including 13 with hyaline membrane disease, were studied to assess the effects of alterations in ventilator settings on mean airway pressure (MAP), blood gases, and intracranial pressure (ICP). The study involved random alterations in peak inspiratory pressure (PIP), positive end-expiratory pressure (PEEP), and inspiratory/expiratory ratio while MAP, PaO2, ICP, and end-tibal PCO2 were continuously monitored. The results showed a significant relationship between MAP and PaO2 that was expressed as the change in PaO2 per millimeter of mercury change in MAP (delta PaO2/delta MAP) with a mean delta PaO2/delta MAP of 4.92. The delta PaO2/delta MAP was highest for changes in PEEP (6.08), followed by PIP (5.07), and inspiratory/expiratory ratio (1.9). There was a significant relationship between alterations in PEEP and PIP vs PaCO2 and pH. Increases in PEEP and decreases in PIP resulted in an elevated PaCO2 and a lowered pH, and decreases in PEEP and increases in PIP resulted in a decreased PaCO2 and an elevated pH. There was no significant relationship between MAP and ICP, but there was a significant association between delta ICP and delta PaCO2 during alterations in PIP (r = .64, P less than .001). Increases in PEEP will lead to the greatest increase in PaO2 per change in MAP, followed by increase in PIP and inspiratory/expiratory ratio using a pressure-limited ventilator.

Cardiopulmonary resuscitation in the very low birth weight infant: the Vermont Oxford Network experience.

OBJECTIVE: The limited literature available to date suggests that the use of delivery room cardiopulmonary resuscitation (DR-CPR) is associated with very poor outcomes, especially for extremely low birth weight infants. We reviewed the cumulative experience of the Vermont Oxford Network to determine the actual utilization of DR-CPR and the neonatal outcomes of such infants. METHODS: A retrospective review of information available in the Vermont Oxford Network Database for the years 1994 to 1996. The data set was collected from 196 neonatal units who participate in the Network (data for infants 401 to 500 g were from 1996 only). Infants were eligible for study if they received DR-CPR defined as the administration of chest compressions and/or epinephrine in the delivery room as noted on the Vermont Oxford Network Database record. RESULTS: Information regarding survival was available for 27 707 newborns with birth weights from 501 to 1500 g, and 497 infants with birth weights from 401 to 500 g. There were 24 001 (86.6%) survivors. Overall DR-CPR was given to 9.3% of infants from 401 to 500 g and 6% of infants from 501 to 1500 g, 82.1% receiving chest compressions, and 66.7% receiving epinephrine. Survival of infants receiving DR-CPR was 23. 9% for infants of 401 to 500 g, and 63.3% for infants of 501 to 1500 g, compared with 16.7% and 87.9% for infants in these weight groups not receiving DR-CPR. Survival was greater for infants of 501 g or greater without DR-CPR compared with those who received this intervention within each 250-g birth weight subgroup. For infants of <1000 g, survival was 53.8% with DR-CPR compared with 74.9% without. Head ultrasounds were available for 95.5% of all surviving infants and 96.7% of infants who received DR-CPR. Overall, any grade of intraventricular hemorrhage (IVH) occurred more frequently in infants who received DR-CPR (38%) than in those who did not (21%). Grade 3 or 4 (severe) IVH was seen in 15.3% of infants who received DR-CPR compared with 4.9% of the infants who did not. Overall, survival without severe IVH occurred in 52.2% of DR-CPR infants compared with 81.3% of infants who did not require this intervention. CONCLUSION: The majority of very low birth weight and extremely low birth weight infants who receive DR-CPR survive, and at least half of such infants who survive do not have evidence of severe IVH. Further follow-up studies are required to determine the long-term neurodevelopmental outcome of such infants. The current study does not support the previously noted poor outcome in extremely low birth weight infants who receive DR-CPR.

Contralateral pneumothoraces in the newborn: incidence and predisposing factors.

A prospective study was performed to ascertain the incidence of, and risk factors for, the development of a contralateral pneumothorax in 32 neonates with respiratory distress, without evidence of pulmonary hypoplasia, who had an initial unilateral air leak requiring pleural drainage. The mean postnatal age of occurrence of the first pneumothorax was 31.04 hours (range 0.1 to 92 hours); a subsequent contralateral pneumothorax developed in 14 infants (44%) at a mean postnatal age of 61.5 hours (range 8 to 106 hours). Thirteen of the 14 infants with a subsequent contralateral pneumothorax had pulmonary interstitial emphysema visible on the chest radiograph taken immediately after drainage of the first pneumothorax, compared with eight of the 18 infants without a contralateral pneumothorax (P less than .005). Other factors significantly associated with a contralateral pneumothorax were alveolar-arterial oxygen gradient (P less than .01) and FiO2 (P less than .005), both measured one hour after the pneumothorax, and gestational age (P less than .05). Multivariate discriminant function analysis did not usefully add to the predictive power of pulmonary interstitial emphysema alone. Infants with pulmonary interstitial emphysema at the time of an initial unilateral pneumothorax are at significant risk for the development of a contralateral pneumothorax.

Limitations of self-inflating resuscitators.

In an effort to characterize the performance of self-inflating resuscitators, three examples of three models were subjected to laboratory testing: the Ohio Hope II resuscitator (Ohio Medical Products, Madison, WI), the PMR-2 resuscitator (Puritan Medical Products, Lenexa, KS), and the Laerdal resuscitator (AS Laerdal, Stavanger, Norway). The devices were connected to a test lung and compressed at frequencies of from 10 to 60 and at greater than 60 breaths per minute at 5, 10, and 15 L/min of flow. These devices were used with and without a reservoir and were compressed at less than and more than the pop-off valve pressures. The results revealed that all devices equipped with reservoirs delivered a significantly higher oxygen concentration than those without (P less than .001), and that activation of the pop-off valve significantly reduced Fio2 under all conditions (P less than .005). The pop-off valves for each device were activated throughout a wide range of pressures, the Laerdal 41 to 72 cm H2O, PMR-2 51 to 97 cm H2O, and the Ohio Hope II 38 to 106 cm H2O, well in excess of the manufacturer's specifications. Only the Laerdal with reservoir was able to deliver an Fio2 of greater than 0.9 when compressed at more than the pop-off valve pressure at rates of up to 30 breaths per minute using flows of 10 L/min, and it was the only device to produce Fio2 values of greater than 0.9 at all rates to 60 breaths per minute when compressed at less than the pop-off valve pressure.(ABSTRACT TRUNCATED AT 250 WORDS)

Dose-response relationship of doxapram in the therapy for refractory idiopathic apnea of prematurity.

Eighteen infants with idiopathic apnea of prematurity refractory to therapeutic levels of aminophylline were treated with incremental doses of doxapram beginning at 0.5 mg/kg/h. Continuous recording of heart rate, thoracic impedance, and transcutaneous PO2 demonstrated that 47% of the infants satisfied objective response criteria at the lowest dose, 53% responded at 1.0 mg/kg/h, 65% at 1.5 mg/kg/h, 82% at 2.0 mg/kg/h, and 89% at the highest allowed dose of 2.5 mg/kg/h. The mean serum doxapram concentration at the response dose was 2.9 +/- 1.3 micrograms/mL, and all infants who responded had levels greater than 1.5 micrograms/mL. BP was significantly elevated at doses higher than 1.5 mg/kg/h (P less than .05). Minute ventilation significantly increased and PCO2 significantly decreased as the doxapram dosage was increased (P = .02). Terminal elimination half-life was 9.9 +/- 2.9 hours. When doxapram is used for treatment of refractory neonatal apnea the starting dosage should be no more than 0.5 mg/kg/h.

Discordance of signs in monozygotic twins concordant for the Goldenhar anomaly.

Concordance for Goldenhar anomaly has been described in monozygotic (MZ) twins on 2 occasions but never in dizygotic (DZ) twins. In both cases the twins were similarly, although not identically, affected. We report on a pair of probably monozygotic twins (8% probability of DZ) who presented with extremely diverse manifestations of this anomaly complex. One of them required a tracheostomy because of obstructive apnea due to severe micrognathia and subsequently died. This twin had a midline lower lip cleft which has not previously been described in the Goldenhar anomaly.

The hemodynamic effects of prolonged respiratory alkalosis in anesthetized newborn piglets.

OBJECTIVE: To test the hypothesis that prolonged alkalosis decreases cardiac output and, furthermore, exacerbates hypoxic pulmonary vasoconstriction, as respiratory alkalosis is frequently induced as a therapy for persistent pulmonary hypertension of the newborn despite a lack of controlled evidence of improved outcomes. Potential adverse effects of prolonged alkalosis have been demonstrated. METHOD: Two groups (control, n = 6, and hypocapnic alkalosis, n = 6) of 1-3 day old fentanyl-anesthetized, vecuronium-paralyzed piglets were instrumented to measure cardiac index (CI) and mean systemic (MAP) and pulmonary (PAP) arterial pressures. Baseline values were recorded. Alveolar hypoxia was then induced to achieve an arterial oxygen saturation of between 50 and 60% for 15 min. Respiratory alkalosis was then induced, by increasing ventilation to achieve a pH between 7.55-7.60, and was continued for 240 min. Inspired carbon dioxide was used with hyperventilation in the control group to maintain pressure of arterial carbon dioxide (PaCO2) at 35-45 mmHg and pH of 7.35-7.45. Hypoxia was induced again at 15 and 240 min. Pulmonary and systemic vascular resistances (PVR and SVR) were calculated. RESULTS: Prolonged alkalosis led to a significant and progressive fall in mean MAP from 61 (SD 7) mmHg at the start of the study falling to 50 (SD 6.9, p = 0.043), with no effect on CI. Calculated SVR decreased (0.45 SD 0.03 vs 0.36 SD 0.05). There were no statistically significant changes in any of the variables in the control group. Neither acute nor prolonged respiratory alkalosis had a significant effect on hypoxic pulmonary vasoconstriction. CONCLUSIONS: Prolonged hyperventilation leads to systemic hypotension, however it does not exacerbate hypoxic pulmonary vasoconstriction.