Longitudinal follow-up of a cohort of newborn infants treated with inhaled nitric oxide for persistent pulmonary hypertension

Association of Right Ventricular Dysfunction with Risk of Neurodevelopmental Impairment in Infants with Pulmonary Hypertension

(1) Background: Pulmonary hypertension (PH) increases pulmonary vascular resistance and right ventricular (RV) afterload. Assessment of RV systolic function in PH using RV fractional area change (RV FAC) as a marker directly correlates with mortality and the need for extracorporeal membrane oxygenation (ECMO). However, few studies have assessed neurodevelopmental outcomes. We hypothesize that cardiac RV systolic dysfunction with lower RV FAC is associated with worse neurodevelopmental impairment (NI). (2) Methods: Retrospective study of 42 subjects with PH to evaluate neurodevelopmental outcomes in the first two years of life based on (i) subjective assessment of RV systolic function and (ii) RV FAC, a specific echocardiographic marker for RV function. (3) Results: Subjects from the initial study cohort (n = 135) with PH who had long-term follow-up were divided into RV dysfunction (study, n = 20) and non-RV dysfunction (control, n = 22) groups. RV FAC in the study vs. control group (0.18 vs. 0.25) was lower (p = 0.00017). There was no statistically significant difference in NI either with RV dysfunction or lower RV FAC. Although not significant, RV dysfunction was associated with longer mean duration of mechanical ventilation, time on ECMO, and length of stay. In the initial cohort (135), mortality was 16.3% and the percentage of NI was 62%. (4) Conclusions: Neonatal pulmonary hypertension is associated with a high degree of neurodevelopment impairment. Early RV systolic dysfunction, as identified by RV FAC, was not an optimal predictive biomarker for infants with PH and neurodevelopmental impairment.

Clinical Characteristics and Risk Factors for Developing Pulmonary Hypertension in Children with Down Syndrome

OBJECTIVES

To determine the incidence, characteristics of, and risk factors contributing to the development of pulmonary hypertension in children with Down syndrome.

STUDY DESIGN

This retrospective, review of a large cohort (n = 1242) of children with Down syndrome receiving care at a specialized referral center evaluated clinical data and serial echocardiograms from a clinic database and electronic medical records. Pulmonary hypertension characteristics and comorbidities were reviewed. Pulmonary hypertension was considered transient if echocardiographic evidence of pulmonary hypertension resolved without recurrence, persistent if no resolution, and recurrent if evidence of pulmonary hypertension returned after a period of resolution.

RESULTS

The incidence of pulmonary hypertension in children with Down syndrome was 28% (n = 346). Median age at initial diagnosis was 5 days (range: 0-7067 days). Pulmonary hypertension was differentiated into transient (70%), persistent (15%), and recurrent (15%) disease. Median duration of transient pulmonary hypertension was 8 months (range: 0.1-130.2 months). Median age at recurrence was 2.5 years (range 0.2-11.5 years). Initial pulmonary hypertension diagnosis was classified as World Health Organization group I disease in 82%, with 45% associated with congenital heart disease (CHD), and 38% persistent pulmonary hypertension of the newborn (PPHN). The pulmonary hypertension recurrence rate was significant and similar for both those with initial PPHN (12%) and non-PPHN (16%). A majority (87%) of patients with recurrent pulmonary hypertension were classified as World Health Organization group III. Frequently identified comorbid conditions included CHD, obstructive sleep apnea, intermittent hypoxia, and recurrent pneumonia.

CONCLUSIONS

Pulmonary hypertension is common in children with Down syndrome, is typically transient, and related to CHD or PPHN but can recur in the setting of respiratory disease such as obstructive sleep apnea, intermittent hypoxia, and recurrent pneumonia.

Pulmonary hypertension's variegated landscape: a snapshot

The many types of pulmonary hypertension (PH) are so protean in their biological origin, histological expression, and natural history that it is difficult to create a summary picture of the disease, or to easily compare and contrast characteristics of one type of PH with another. For newcomers to the field, however, such a picture would facilitate a broad understanding of PH. In this paper, we suggest that four characteristics are fundamental to describing the nature of various types of PH, and that taken together they define a number of patterns of PH expression. These characteristics are histopathology, developmental origin, associated clinical conditions, and potential for resolution. The “snapshot” is a way to concisely display the ways that these signal characteristics intersect in select specific types of PH, and is an effort to summarize these patterns in a way that facilitates a “big picture” comprehension of this disease.

Management of Supplemental Oxygen for Infants with Persistent Pulmonary Hypertension of Newborn: A Survey

Objective To evaluate practice variations amongst neonatologists regarding oxygen management in neonates with persistent pulmonary hypertension of newborn (PPHN). Study Design An online survey was administered to neonatologists to assess goal oxygenation targets and oxygen titration practices in PPHN. Response variations were assessed and intergroup comparisons performed. Results Thirty-three percent (492) of neonatologists completed the survey. Twenty-eight percent reported using specific oxygen titration guidelines. Majority of respondents used a combination of oxygen saturation (SpO₂) and arterial oxygen tension (PaO₂) initially to titrate oxygen. Seventy percent of the respondents used higher goal SpO₂ > 95% or 95 to 98% and thirty-eight percent of the respondents used PaO₂ > 80 mm Hg. Physicians with extracorporeal membrane oxygenation experience and those with greater than ten years neonatal intensive care unit experience inclined toward use of SpO₂ alone for oxygen titration and aimed for lower range of SpO₂ and PaO₂ targets. Greater proportion of neonatologists who employed specific oxygen titration guidelines used lower SpO₂ targets. Conclusion Wide practice variations exist amongst neonatologists regarding optimal SpO₂ and PaO₂ targets and oxygen titration practices in the management of PPHN.

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

BACKGROUND

Nitric oxide (NO) is a major endogenous regulator of vascular tone. Inhaled nitric oxide (iNO) gas has been investigated as treatment for persistent pulmonary hypertension of the newborn.

OBJECTIVES

To determine whether treatment of hypoxaemic term and near-term newborn infants with iNO improves oxygenation and reduces rate of death and use of extracorporeal membrane oxygenation (ECMO), or affects long-term neurodevelopmental outcomes.

SEARCH METHODS

We used the standard search strategy of the Cochrane Neonatal Review Group to search the Cochrane Central Register of Controlled Trials (CENTRAL; 2016, Issue 1), MEDLINE via PubMed (1966 to January 2016), Embase (1980 to January 2016) and the Cumulative Index to Nursing and Allied Health Literature (CINAHL; 1982 to January 2016). We searched clinical trials databases, conference proceedings and reference lists of retrieved articles for randomised controlled trials and quasi-randomised trials. We contacted the principal investigators of studies published as abstracts to ascertain the necessary information.

SELECTION CRITERIA

Randomised studies of iNO in term and near-term infants with hypoxic respiratory failure, with clinically relevant outcomes, including death, use of ECMO and oxygenation.

DATA COLLECTION AND ANALYSIS

We analysed trial reports to assess methodological quality using the criteria of the Cochrane Neonatal Review Group. We tabulated mortality, oxygenation, short-term clinical outcomes (particularly use of ECMO) and long-term developmental outcomes.

STATISTICS

For categorical outcomes, we calculated typical estimates for risk ratios and risk differences. For continuous variables, we calculated typical estimates for weighted mean differences. We used 95% confidence intervals and assumed a fixed-effect model for meta-analysis.

MAIN RESULTS

We found 17 eligible randomised controlled studies that included term and near-term infants with hypoxia.Ten trials compared iNO versus control (placebo or standard care without iNO) in infants with moderate or severe severity of illness scores (Ninos 1996; Roberts 1996; Wessel 1996; Davidson 1997; Ninos 1997; Mercier 1998; Christou 2000; Clark 2000; INNOVO 2007; Liu 2008). Mercier 1998 compared iNO versus control but allowed back-up treatment with iNO for infants who continued to satisfy the same criteria for severity of illness after two hours. This trial enrolled both preterm and term infants but reported most results separately for the two groups. Ninos 1997 studied only infants with congenital diaphragmatic hernia.One trial compared iNO versus high-frequency ventilation (Kinsella 1997).Six trials enrolled infants with moderate severity of illness scores (oxygenation index (OI) or alveolar-arterial oxygen difference (A-aDO2)) and randomised them to immediate iNO treatment or iNO treatment only after deterioration to more severe criteria (Barefield 1996; Day 1996; Sadiq 1998; Cornfield 1999; Konduri 2004; Gonzalez 2010).Inhaled nitric oxide appears to have improved outcomes in hypoxaemic term and near-term infants by reducing the incidence of the combined endpoint of death or use of ECMO (high-quality evidence). This reduction was due to a reduction in use of ECMO (with number needed to treat for an additional beneficial outcome (NNTB) of 5.3); mortality was not affected. Oxygenation was improved in approximately 50% of infants receiving iNO. The OI was decreased by a (weighted) mean of 15.1 within 30 to 60 minutes after the start of therapy, and partial pressure of arterial oxygen (PaO2) was increased by a mean of 53 mmHg. Whether infants had clear echocardiographic evidence of persistent pulmonary hypertension of the newborn (PPHN) did not appear to affect response to iNO. Outcomes of infants with diaphragmatic hernia were not improved; outcomes were slightly, but not significantly, worse with iNO (moderate-quality evidence).Infants who received iNO at less severe criteria did not have better clinical outcomes than those who were enrolled but received treatment only if their condition deteriorated. Fewer of the babies who received iNO early satisfied late treatment criteria, showing that earlier iNO reduced progression of the disease but did not further decrease mortality nor the need for ECMO (moderate-quality evidence). Incidence of disability, incidence of deafness and infant development scores were all similar between tested survivors who received iNO and those who did not.

AUTHORS' CONCLUSIONS

Inhaled nitric oxide is effective at an initial concentration of 20 ppm for term and near-term infants with hypoxic respiratory failure who do not have a diaphragmatic hernia.

High prevalence of minor neurologic deficits in a long-term neurodevelopmental follow-up of children with severe persistent pulmonary hypertension of the newborn: a cohort study

BACKGROUND

Persistent pulmonary hypertension of the newborn (PPHN) is a severe condition that determines a profound brain hypoxia. Inhaled nitric oxide was approved for the treatment of PPHN since the end of the 1990s. The debate upon the long term outcome of these children is still open. Our aim was to investigate the incidence of minor long-term neurodevelopmental problems in a cohort of children affected by severe PPHN.

METHODS

All neonates with severe PPHN treated with inhaled nitric oxide in our facility between 01.01.02 and 31.12.07 were seen in a follow up visit and evaluated with a neurodevelopmental scale, according to their age at the time of observation.

RESULTS

in the study period 31 children were diagnosed with severe PPHN. 29 survived. 27 accepted to come for follow-up. Mean age: 41 months (range 12 - 70 months).26% of the evaluated children had some behavioural problems, while 22% had some language disturbances.

CONCLUSIONS

This is the first neurodevelopmental follow-up of neonates with PPHN in which children older than 36 months have been evaluated.There is an unexpected high incidence of minor neurological deficits, mainly regarding the fields of language and behaviour. These deficits seem to be related to the severity of illness rather than to the treatment. Language and behaviour are considered "higher functions" in humans and their integrity can be better defined in older children.

School-age outcomes of newborns treated for persistent pulmonary hypertension

OBJECTIVE

The aim of this study was to describe the school-age outcome of a cohort of children treated with intensive care support for persistent pulmonary hypertension of the newborn (PPHN).

STUDY DESIGN

From 187 term newborns treated for PPHN as neonates, 109 were seen at school age (73% of 150 survivors and 58.2% of the original cohort). Of these 109 term newborns, 77 were treated with inhaled nitric oxide (iNO); of which 12 received extracorporeal membrane oxygenation (ECMO). The remaining 32 received conventional management with no exposure to iNO. Patients were seen at school age (mean 7.1 years). A medical history and physical exam were completed, growth was measured, and chest X-ray and echocardiogram were performed. Psychometric assessments included the Wechsler Scales (Preschool or Child), Vineland Adaptive Behavior Scales, Kaufman Test of Educational Achievement, Children's Category Test, Wisconsin Card Sorting Test and Achenbach Child Behavior Checklist.

RESULT

Medical, neurodevelopmental and social/emotional/behavioral outcome did not differ between children treated with iNO, with or without ECMO, and those managed with no exposure to iNO. Overall, 24% had respiratory problems, 60% had abnormal chest X-rays and 6.4% had some sensorineural hearing loss. The cohort performed at the average level for full scale IQ, adaptive function, academic achievement, higher-order cognition and executive functioning, and social/behavioral/emotional functioning. Overall, 9.2% of the cohort had a full scale IQ less than 70 and 7.4% had an IQ from 70 to 84.

CONCLUSION

The outcome for this cohort of children treated as newborns for PPHN, which included a large group of infants exposed to iNO, was comparable to previous reports of children treated with ECMO or conventionally.

Follow-up of 5- to 11-year-old children treated for persistent pulmonary hypertension of the newborn

AIM

Determine the prevalence of sensorineural hearing loss (SNHL) and relate this to cumulative exposure to hypoxia, hypocapnia and hypotension. Describe chronic health problems among 5- to 11-year-old children treated for persistent pulmonary hypertension of the newborn (PPHN).

METHODS

The index group consisted of 85 children and a reference group was matched for age, sex and municipality of current residence. Questionnaires were sent to the families. The families in the index group were asked to participate in an examination of their child's hearing.

RESULTS

Seven children (11%) had SNHL. SNHL was not associated with hypoxia, hypocapnia or hypotension during treatment for PPHN. In the index group chronic health problems were reported in 42% compared with 17% in the reference group (chi-square test, p = 0.001). Twenty-one percent in the index group were treated with bronchodilator therapy compared with 8% in the reference group (chi-square test, p = 0.028). In the index group five children had cerebral palsy and two had developmental delay. Nineteen percent in the index group and 5% in the reference group had remedial education (chi-square test, p = 0.008).

CONCLUSION

Children treated for PPHN are at high risk for SNHL. Exposure to hypoxia, hypocapnia or hypotension did not predict SNHL. The incidence of chronic health problems and use of remedial education was high.

Developmental outcomes in persistent pulmonary hypertension treated with nitric oxide therapy

BACKGROUND

The aim of the present study was to assess 3 year auditory and neurodevelopmental outcomes of persistent pulmonary hypertension of the newborn (PPHN) before and after introducing inhaled nitric oxide (i-NO) therapy, and to detect the clinical factors affecting poor outcome.

METHODS

A retrospective historical cohort study of 26 survivors with PPHN with oxygenation index (OI) >or=25 (13 infants without i-NO therapy, control group; 13 with i-NO therapy, i-NO group) was performed. Auditory brainstem response (ABR) at 6 and 12 months and neurodevelopmental outcomes at 3 years of age were evaluated.

RESULTS

ABR abnormalities at 6 months were observed in one infant in the i-NO group and six in the control group (P = 0.04). At 1 year, one infant in the i-NO group and two of six infants in the control group still had ABR abnormality. In the i-NO group, two children had abnormal neurodevelopmental outcomes, as compared with five children in the control group at 3 year follow up. Two children in the control group and no children in the i-NO group had hearing loss at 3 years of age. Hypocapnea (P = 0.04) and elevated creatine phosphokinase (P = 0.04) were found to be most predictive for neurodevelopmental abnormality.

CONCLUSION

Avoidance of excessive hypocapnea via introduction of i-NO therapy might reduce both ABR and neurodevelopmental abnormalities.

Respiratory function during infancy in survivors of the INNOVO trial

RATIONALE

Despite encouraging reports suggesting that inhaled nitric oxide (iNO) appear to improve outcome in hypoxemic term and near term infants by improving oxygenation and reducing need for ECMO, the long-term benefits of iNO remain unclear. This study aimed to compare lung function at approximately 1 year in infants who were and were not randomly allocated to iNO as part of their neonatal management for severe respiratory failure at birth. Furthermore, results were compared to lung function of healthy infants.

METHODS

Maximal expiratory flow at functional residual capacity (V'maxFRC) was measured at approximately 1 year of age (corrected for any prematurity) in survivors of the INNOVO trial. Results were expressed as Z-scores, adjusted for sex and body size, based on data from healthy controls using identical techniques.

RESULTS

Technically satisfactory results were obtained in 30 infants (53% < 34 weeks gestation), 19 of whom were randomized to receive iNO V'maxFRC. Z-score was significantly reduced in infants with prior respiratory failure, whether or not they had been allocated to iNO (mean (SD) Z-score: -2.0 (1.2) and -2.6 (1.1), respectively, 95% CI difference; iNO vs. no iNO: -0.3; 1.6, P = 0.2). There was significant respiratory morbidity in both groups during the first year of life.

CONCLUSIONS

These results suggest that airway function remains reduced at 1 year of age following severe respiratory failure at birth, whether or not iNO is administered.

Neurodevelopmental outcome of infants with meconium aspiration syndrome: report of a study and literature review

There is a paucity of information on long-term outcome of infants who have suffered from meconium aspiration syndrome (MAS) in the neonatal period. We analyzed long-term developmental outcome data of 35 infants who were admitted to the neonatal intensive care unit (NICU) at the University of Illinois Hospital at Chicago (UICMC) with a diagnosis of MAS, and we reviewed the literature pertinent to the subject. The objective of the study was to assess the neurodevelopment status of MAS infants and compare the possible effects of different variables that are known to affect the later developmental outcome. The variables included mode of delivery, APGAR score, cord pH, mode of treatment, and neurological findings during the course of NICU. The infants were enrolled in the developmental follow-up program (DFUP) after discharge from the nursery for assessment of long-term developmental status and neurodevelopmental outcome. In order to assess the impact of the treatment on long-term outcome and compare our findings with previously published reports, we also reviewed the previously published literature on neurodevelopment outcome of infants treated for MAS (with different modalities) during the last three decades. Total of 35 infants with a diagnosis of MAS admitted to the NICU at UICMC were followed in the DFUP clinic for 3 years during January 1999 to September 2001. The medical records of these infants were reviewed for the mode of delivery, APGAR score, birth weight (BW), gestational age, mode of treatment during the neonatal period, and neurodevelopment status. 19/35 (54%) infants were delivered vaginally, 16/35 (46%) by cesarean section (C-section). All were treated in the delivery room using the standard resuscitation protocol. Following initial resuscitation, all except three required intubation and ventilation for varying duration. One infant required inhaled nitric oxide therapy, and two required extracorporeal membrane oxygenation treatment. Subsequent to discharge, the infants were evaluated in the clinic at 2 months of age, and then every 4 months up to 3 years. The developmental assessment of mental development index (MDI), psychomotor development index (PDI), and behavior rating scale (BRS) were obtained using the Bayley II infant motor scale, and neurodevelopment evaluation was performed using the Amiel-Tison technique. Speech evaluation was performed in infants >18 months using the Rossetti Infant-Toddler language scale. Infants were considered normal when MDI and PDI scores were >85 to 110; mildly delayed when scores were >70 to 84; and severely delayed if the scores were <69. In addition, neurological evaluation also confirmed the disability. The report is based on the final analysis of 29 infants. Data of six infants were not included in the final analysis because of incomplete information. The mean BW of the infants was 3269+/-671 g; mean gestational age was 39.5+/-3.1 weeks. The median APGAR score at 1' was 4, and at 5' was 6. Out of 29, 11 (38%) infants were normal. Out of 29, 2 infants (7%) had cerebral palsy (CP) and 4 (14%) had severe delay at 12 months of age. Out of 29, 2 who were neurologically disabled had PDI <69. Out of 29, 12 (41%) had mild delay in speech. No statistical difference in neurodevelopment was found in infants born vaginally or by C-section. Our findings show poor outcome (CP and global delay) in 21% of infants who suffered MAS, even though the majority of the infants (26/29) responded to conventional ventilator support alone. No difference was found in the outcome of infants between NSVD vs C-section delivery. These findings suggest that infants with the diagnosis of MAS manifest later neurodevelopmental delays, even if they respond well to conventional treatment. This abstract was presented at the Society for Pediatric Research Annual Meeting, 2000.

Airway function in infants treated with inhaled nitric oxide for persistent pulmonary hypertension

RATIONALE

Inhaled nitric oxide (iNO), used for treatment of persistent pulmonary hypertension of newborn (PPHN), is an oxygen free radical with potential for lung injury. Deferring ECMO with iNO in these neonates could potentially have long-term detrimental effects on lung function. We studied respiratory morbidity (defined as occurrence of respiratory infections requiring treatment, episodes of wheezing, and/or need for ongoing medications following discharge) and airway function at 1 year postnatal age in term neonates treated with iNO but not ECMO for PPHN, and compared data from similar infants recruited to the UK ECMO Trial randomized to receive ECMO or conventional management (CM).

METHODS

Maximal expiratory flow at FRC (V(') (maxFRC)) was measured in infants treated with iNO for PPHN (oxygenation index >or=25) at birth.

RESULTS

V(') (maxFRC) was measured in 23 infants and expressed as z-scores, to adjust for sex and body size and compared to data from 71 (46 ECMO, 25 CM) infants studied at a similar age in the ECMO Trial. Respiratory morbidity was low in iNO group. V(') (maxFRC) z-score was lower than predicted in all groups (P < 0.001), with no significant difference between those treated with iNO [mean (SD) z-score: -1.65 (1.2)] and those treated with ECMO [-1.59 (1.2)] or CM [-2.1(1.0)]. Within iNO, ECMO and CM groups; 26%, 37% and 56%, respectively, had V(') (maxFRC) z-scores below normal.

CONCLUSIONS

Respiratory outcome at 1 year in iNO treated neonates with moderately severe PPHN is encouraging, with no apparent increase in respiratory morbidity when compared to the general population. Sub-clinical reductions in airway function are evident at 1 year, suggesting that continuing efforts to minimize lung injury in the neonatal period are warranted to maximize lung health in later life.

Early inhaled nitric oxide therapy for term and near-term newborn infants with hypoxic respiratory failure: neurodevelopmental follow-up

OBJECTIVE

To report the neurodevelopmental outcome of infants enrolled in a randomized multicenter trial of early inhaled nitric oxide (iNO) in term and near-term neonates with hypoxic respiratory failure and pulmonary hypertension.

STUDY DESIGN

Neonates born at > or = 34 weeks gestation who required assisted ventilation and had an oxygenation index > or = 15 and < 25 were randomized to an early iNO group or a control group. A comprehensive neurodevelopmental assessment of survivors was performed at age 18 to 24 months.

RESULTS

The trial enrolled 299 infants, of which 266 (89%) survived to age 18 to 24 months (136 in the early iNO group and 130 in the control group). Follow-up evaluations were done on 234 (88%) of surviving infants. There were no differences between the 2 groups in the incidence of neurodevelopmental impairment (early iNO, 27%; control, 25%) and hearing impairment (early iNO, 23%; control, 24%). Mental development index scores were similar in the 2 groups; however, psychomotor developmental index scores were significantly higher in the control group (early iNO, 89 +/- 17.7; control, 93.5 +/- 18.4).

CONCLUSIONS

Early iNO therapy for hypoxic respiratory failure in term and near-term infants is not associated with an increase in neurodevelopmental impairment or hearing loss at 18 to 24 months postnatal age.

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.

Cesarean section upon request: is it appropriate for everybody?

The request for cesarean section without medical indication has become one of the dilemmas faced by the obstetrician. Most recent studies that compare vaginal delivery with elective cesarean section find them equally safe. This comparison is lacking in the option of trial of labor, which may result in an assisted vaginal delivery or intrapartum cesarean section, both with increased morbidity and mortality for the mother and newborn. When considering elective cesarean section, the obstetrician has to take into account improved anesthetic techniques and the decrease in morbidity and mortality after cesarean section with the trend toward patient autonomy to decide on her own treatment. On the other hand, the obstetrician has to advise his patient of the best treatment with respect to possible complications in future pregnancies, such as placental complications and increased morbidity and mortality resulting from repeated cesarean sections. The advantage of cesarean section for pelvic floor protection does not exist after three consecutive cesarean sections and equals the rate of urinary incontinence after consecutive three vaginal deliveries. In countries such as ours, where most women wish for several children, the risk-benefit balance is toward repeated spontaneous vaginal deliveries.

Meconium aspiration induces oxidative injury in the hippocampus of newborn piglets

BACKGROUND

Meconium aspiration-induced hypertensive lung injury has been associated with neuronal damage in the newborn, but the mechanisms of the injury are poorly known.

AIMS

The aim of the study was to determine the contribution of oxidative stress to the brain damage after pulmonary meconium contamination.

STUDY DESIGN

Sixteen anesthetized and ventilated newborn piglets were studied for 6 h. Eight piglets were instilled with a bolus of human meconium intratracheally and eight piglets with saline instillation served as controls. Brain tissue lipid peroxidation products (TBARS), reduced glutathione (GSH), myeloperoxidase activity and oxidized DNA were analyzed as indicators of oxidative stress.

RESULTS

Meconium aspiration did not change the systemic or carotid hemodynamics, but caused a well-established pulmonary hypertensive response. Sustained increase in additional oxygen demand was also observed after meconium insult, but no actual hypoxemia or hypercarbia was evident during the whole study period. Myeloperoxidase activity was elevated in the cerebellum after pulmonary meconium instillation, whereas concentrations of peroxidation products and glutathione were similar in the cortical, cerebellar and hippocampal regions of the two groups. Still, the amount of oxidized DNA was increased in the hippocampus of the meconium-aspirated piglets when compared to controls.

CONCLUSIONS

Our data thus suggest that oxidative injury associated with pulmonary, but not systemic, hemodynamic disturbances may contribute to hippocampal damage after meconium aspiration in newborns.

Pulmonary vasodilator therapy in congenital diaphragmatic hernia: acute, late, and chronic pulmonary hypertension

Pulmonary hypertension complicates the course of many newborns with congenital diaphragmatic hernia. In the most severe cases, the fetal condition of markedly elevated pulmonary vascular resistance persists after birth and is associated with hypoxemic respiratory failure and severe disturbances in cardiac performance. Late pulmonary hypertension (weeks to months after birth) is increasingly recognized in this population, and chronic pulmonary vascular abnormalities (months to years after birth) are now being discovered. In this review, we will discuss the pathophysiology of acute, late, and chronic pulmonary hypertension in patients with congenital diaphragmatic hernia. We will also review the role of currently available pulmonary vasoactive drugs in the management of pulmonary hypertension in this population.

Three-year follow up of term and near-term infants treated with inhaled nitric oxide

BACKGROUND

The present study describes the outcome at 3 years in term and near-term infants treated with inhaled nitric oxide (iNO) for persistent pulmonary hypertension of the newborn (PPHN).

METHODS

The study population consisted of 18 infants delivered at 34 weeks by best obstetric estimate who were admitted to the neonatal intensive care units with a diagnosis of PPHN.

RESULTS

Eighteen infants (mean gestational age 38.5 +/- 2.6 weeks, mean birthweight 3015 +/- 587 g) were treated with iNO. The mean oxygenation index before iNO was 27.2 +/- 15.2. Responses to iNO were classified into three groups: (i) early response in eight infants; (ii) late response in two; and (iii) poor response in eight infants. Three infants died within seven postnatal days. Fifteen surviving infants were followed up to 3 years. The mean developmental scale was 98.4 +/- 9.0. One infant was diagnosed with severe neurodevelopmental disability due to cerebral palsy. Another infant was diagnosed with mild neurodevelopmental disability because of a low developmental scale. No infant showed significant hearing loss. Five infants had reactive airway disease (RAD) at 18 months, these infants required a significantly longer duration of mechanical ventilation in their neonatal period than non-RAD infants (P = 0.02). The frequency of survival with normal neurodevelopmental outcome was significantly higher in the early response group than the late or poor response groups (P = 0.03).

CONCLUSION

In iNO-treated PPHN, mortality and neurodevelopmental outcome were associated with response to iNO, and pulmonary outcome was associated with duration of mechanical ventilation.

Inhaled nitric oxide and gentle ventilation in the treatment of pulmonary hypertension of the newborn--a single-center, 5-year experience

OBJECTIVE

To evaluate the effect of inhaled nitric oxide (INO) in pulmonary hypertension of the newborn (PH) in a single center over 5 years using gentle ventilation (GV), without hyperventilation or induced alkalosis.

METHODS

Data from 229 consecutive infants with PH of varied etiology treated with INO and GV, and from 67 infants with meconium aspiration syndrome (MAS) and primary PH (PPHN) treated with GV alone were reviewed over a 5-year period (86% outborn). INO was initiated at 25 ppm when PH and severe hypoxemia persisted despite maximal optimal ventilation. Hyperventilation or systemic alkalosis were not attempted.

RESULTS

Mean duration of ventilation was 9.9 +/- 14 days (median 6.5 days). Average mean airway pressure (MAP) dropped from 17.7 +/- 4.3 cm H(2)O at the referral hospital to 13.2 +/- 2.5 cm H(2)O (p < 0.001) following admission to our unit using conventional settings and GV, before starting INO. Mean oxygenation index (OI) dropped from 46.8 +/- 24.5 to 22.7 +/- 21.4 within 24 hours of INO therapy (p < 0.001). Infants with higher baseline pH and lower baseline OI responded better to INO (p < 0.02). Overall survival was 72%. Patients with MAS and PPHN had the best response, 92% survived and there was a 46% reduction in need for extracorporeal membrane oxygenation (ECMO) compared to historical pre-INO period controls (23.9% vs. 12.8%, p < 0.01). In the infants treated with GV alone, the MAP dropped from 17.2 +/- 4.3 cm H2O at the referral hospital to 12.6+/-2.4 after GV was started in our unit.

CONCLUSIONS

We conclude that INO is an effective and well-tolerated therapy for PH in infants receiving GV.

Feasibility of nitric oxide administration by oxygen hood in neonatal pulmonary hypertension

OBJECTIVE

To test the hemodynamic efficacy and feasibility of nitric oxide (NO) administration by oxygen hood in neonatal pulmonary hypertension.

STUDY DESIGN

A double-hood apparatus was used in which a combination of NO, O(2), and N(2) was introduced into the inner hood and suctioned from the outer hood. Chronically instrumented non-intubated piglets were exposed to 10% O(2) (hypoxia; n=8) or group B streptococci infusion (GBS; n=5) to produce pulmonary hypertension and were then exposed to 20 ppm NO.

RESULTS

NO decreased (>50%) pulmonary artery pressure and vascular resistance in both hypoxia- and GBS-induced pulmonary hypertension, with minimal effects on systemic arterial pressure and cardiac output. NO administration could be performed without detectable environmental leakage.

CONCLUSION

Hood NO administration is feasible and shows hemodynamic efficacy in neonatal piglets with pulmonary hypertension.

Persistent pulmonary hypertension of the newborn. Rational therapy based on pathophysiology

Persistent pulmonary hypertension of the newborn is a common disorder among near-term gestation newborns. Persistent pulmonary hypertension of the newborn is characterized by hypoxemia that is frequently refractory to conventional management. This article describes the pathophysiologic basis of the disorder and the current therapy that is based on this knowledge.

Extracorporeal membrane oxygenation 2001. The odyssey continues

Extracorporeal membrane oxygenation was established as a standard of care by demonstrating its ability to save lives in moribund infants. The designs of early studies provided no living cohorts of similarly ill patients by which to measure accurately other (and perhaps to many more important) outcomes of interest: long-term neurodevelopmental outcomes or cost. Prospective cohort studies of neurodevelopmental outcomes post-ECMO demonstrate: (1) because ECMO, as used, saves lives, there will be an increase in the absolute number of handicapped children surviving; (2) there is little evidence that ECMO creates a relative increase in the percent of handicapped children surviving severe respiratory failure. The high direct costs of an ECMO program are measured and well publicized. When such costs are compared with similar therapies in other fields (in such terms as cost per survivor), the cost of ECMO does not seem to be an outlier. Trials of newer therapies, such as iNO, show the capacity to decrease the use of ECMO but have failed to demonstrate either cost-effectiveness or better long-term outcomes. It has not been shown that either society or individual patients have benefited from the decreased need for ECMO.

Child health status, neurodevelopmental outcome, and parental satisfaction in a randomized, controlled trial of nitric oxide for persistent pulmonary hypertension of the newborn

OBJECTIVE

To describe health and neurodevelopmental outcomes and parental satisfaction with hospital care among surviving intervention and control enrollees in a randomized, controlled trial of nitric oxide for persistent pulmonary hypertension of the newborn (PPHN).

METHODS

All surviving enrollees 1 to 4 years of age were eligible for follow-up. Outcomes were assessed by telephone using a trained interviewer and standardized instruments. Domains assessed included parental report of specific conditions and hospital use, rating of general health, cognitive and motor development, behavior problems, temperament, and satisfaction with the hospital stay. Fisher's exact test and the Wilcoxon rank sum test assessed differences between intervention and control infants.

RESULTS

Interviews were completed on 60 of 83 survivors (72%). Eighteen families (22%) could not be located, 2 (2%) were non-English-speaking, and 3 (4%) declined participation. No postdischarge deaths were ascertained. Among those interviewed, race, income, and education of parents of intervention and controls were comparable, as were entry oxygenation index, extracorporeal oxygenation utilization, and days of hospitalization. No differences were found in pulmonary, neurologic, cognitive, behavioral, or neurosensory outcomes; hospital readmission rates; or parental ratings of child's health. The overall neurologic handicap rate was 15%. The rate of hearing deficit was 7%. The rate of significant behavioral problems was 26%. Levels of satisfaction expressed were high for each group. No differences in parental ratings were found between the 2 groups.

CONCLUSIONS

No adverse health or neurodevelopmental outcomes have been observed among infants treated with nitric oxide for PPHN. The parents of the critically ill infants enrolled in our clinical trial welcomed their child's inclusion and all expressed satisfaction with the care that their child received while at a tertiary care hospital. Enrollment in either arm of this randomized, controlled trial did not seem to affect parental satisfaction with the hospital care that their child received.

Echocardiographic outcome of infants treated as newborns with inhaled nitric oxide for severe hypoxemic respiratory failure

OBJECTIVE

To determine the cardiovascular outcome of a group of term newborns treated with inhaled nitric oxide (iNO) for severe hypoxemic respiratory failure with associated persistent pulmonary hypertension.

STUDY DESIGN

We performed echocardiographic evaluations in 40 survivors treated for severe neonatal hypoxemic respiratory failure. Each of the 40 had at least 2 follow-up echocardiograms at 3 or 6 and 24 months. These studies were compared with echocardiograms done in infants in a normal, age-matched control group.

RESULTS

Three of 31 infants met echocardiographic criteria for pulmonary hypertension at the 3-month examination. Two of the 3 had associated structural heart disease (1 with an atrial septal defect and 1 with a ventricular septal defect). At 24 months only 1 patient had pulmonary hypertension. This infant had an atrial septal defect that was surgically closed shortly after the 24-month echocardiogram because of the pulmonary hypertension. Group comparisons of 3- and 24-month echocardiographic variables showed no differences between the study and control groups. In the 31 infants in whom serial studies were completed, expected age-related changes were demonstrated between the 3- and 24-month examinations.

CONCLUSIONS

The incidence of residual pulmonary hypertension in infants treated as newborns for severe hypoxemic respiratory failure is low. The group at highest risk is those with structural heart disease.

Decreased use of neonatal extracorporeal membrane oxygenation (ECMO): how new treatment modalities have affected ECMO utilization

OBJECTIVE

Over the last decade, several new therapies, including high-frequency oscillatory ventilation (HFOV), exogenous surfactant therapy, and inhaled nitric oxide (iNO), have become available for the treatment of neonatal hypoxemic respiratory failure. The purpose of this retrospective study was to ascertain to what extent these modalities have impacted the use of neonatal extracorporeal membrane oxygenation (ECMO) at our institution.

METHODS

Patients from 2 time periods were evaluated: May 1, 1993 to November 1, 1994 (group 1) and May 1, 1996 to November 1, 1997 (group 2). During the first time period (group 1), HFOV was not consistently used; beractant (Survanta) use for meconium aspiration syndrome (MAS), persistent pulmonary hypertension of the newborn (PPHN), and pneumonia was under investigation; and iNO was not yet available. During the second time period (group 2), HFOV and beractant treatment were considered to be standard therapies, and iNO was available to patients with oxygenation index (OI) >/=25 x 2 at least 30 minutes apart, or on compassionate use basis. Patients were included in the data collection if they met the following entry criteria: 1) OI >15 x 1 within the first 72 hours of admission; 2) EGA >/=35 weeks; 3) diagnosis of MAS, PPHN or sepsis/pneumonia; 4) <5 days of age on admission; and 5) no congenital heart disease, diaphragmatic hernia, or lethal congenital anomaly.

RESULTS

Of the 49 patient in group 1, 21 (42.8%) required ECMO therapy. Of these ECMO patients, 14 (66.6%) had received diagnoses of MAS or PPHN. Only 3 of the patients that went on to ECMO received beractant before the initiation of bypass (14.3%). All ECMO patients in group 1 would have met criteria for iNO had it been available. Of all patients in group 1, 18 (36.7%) were treated with HFOV, and 13 (26.5%) received beractant. Of the 47 patients in group 2, only 13 (27.7%) required ECMO therapy (compared with group 1). Of these ECMO patients, only 5 (38.5%) had diagnoses of MAS or PPHN, with the majority of patients (61.5%) requiring ECMO for sepsis/pneumonia, with significant cardiovascular compromise. Only 5 of these ECMO patients, all outborn, did not receive iNO before cannulation because of the severity of their clinical status on admission. Of all patients in group 2, 41 (87.2%) were treated with HFOV (compared with group 1), 42 (89.3%) received beractant (compared with group 1), and 18 (44.7%) received iNO.

CONCLUSIONS

The results indicate that ECMO was used less frequently when HFOV, beractant and iNO was more commonly used. The differences in treatment modalities used and subsequent use of ECMO were statistically significant. We speculate that, in this patient population, the diagnostic composition of neonatal ECMO patients has changed over time.

Inhaled nitric oxide in the neonatal period

Pulmonary hypertension of the newborn is an important cause of hypoxaemia, particularly in the at term or near term neonate. It can occur as a primary condition or secondary to a variety of other diseases. Endogenous nitric oxide is an important modulator of vascular tone in pulmonary circulation. Initial uncontrolled studies indicated that inhalation of nitric oxide resulted in a reduction in pulmonary hypertension, with improvement in oxygenation, but no change in the systemic vascular resistance. There have now been a number of randomised trials performed exploring the efficacy of inhaled nitric oxide. These trials have demonstrated that in at term or near term infants, inhaled nitric oxide reduces the combined end point of death or the need for extracorporeal membrane oxygenation. The significant effect seems due to the reduced extracorporeal membrane oxygenation requirement. No such beneficial effect has been consistently reported in infants with congenital diaphragmatic hernia. Randomised trials have failed to highlight long-term positive results in preterm infants. Inhaled nitric oxide has side effects, although those due to nitrogen dioxide and methaemoglobin formation can be minimised by appropriate nitric oxide delivery. It is important to use the smallest effective nitric oxide dose, continuous nitric oxide and nitrogen dioxide monitoring and frequent methaemoglobin analyses. Careful patient selection should be undertaken, avoiding those at high risk of haemorrhagic complications. Longer term follow-up studies are required to determine the real risk:benefit ratio of inhaled nitric oxide treatment.

Inhaled nitric oxide in term and near-term infants: neurodevelopmental follow-up of the neonatal inhaled nitric oxide study group (NINOS)

BACKGROUND

Inhaled nitric oxide (INO) improved oxygenation and reduced the occurrence of death or extracorporeal membrane oxygenation in term and near-term hypoxic neonates. We report the results of neurodevelopmental follow-up of infants enrolled in the NINOS trial.

METHODS

Hypoxic infants >/=34 weeks' gestation and <14 days of age were randomized to 20 ppm INO or 100% oxygen as control. Comprehensive neurodevelopmental assessment of survivors occurred at 18 to 24 months of age.

RESULTS

A total of 235 infants were enrolled in the original trial. There were 36 deaths, 20 of 121 infants in the control group and 16 of 114 infants in the INO-treated group. Of the 199 surviving infants, 173 (86.9%) were seen for follow-up (88 members of the control group and 85 members of the INO-treated group), and 135 infants were normal (69 [79.3%] members of the control group and 66 [77.6%] members of the INO-treated group). Twenty-two infants had sensorineural hearing loss (12 members of the control group and 10 members of the INO-treated group). Moderate to severe cerebral palsy occurred in 13 infants (7 infants in the control group and 6 infants in the INO-treated group). Mental developmental index scores (87 +/- 18.7 in the control group vs 85 +/- 21.7 in the INO-treated group) and psychomotor developmental index scores (93.6 +/- 17.5 in the control group vs 85.7 +/- 21.2 in the INO-treated group) were not different. A total of 29.6% of the control group compared with 34.5% of the INO-treated group had at least one disability. Infants with congenital diaphragmatic hernia, enrolled in a separate but parallel trial, had similar outcomes with a higher incidence of sensorineural hearing loss.

CONCLUSION

Inhaled nitric oxide is not associated with an increase in neurodevelopmental, behavioral, or medical abnormalities at 2 years of age.

Nitric oxide therapy for the newborn infant

Inhaled nitric oxide (INO) is a novel selective pulmonary vasodilator without significant effects on the systemic circulation. Initial case studies of near-term newborn infants with hypoxic respiratory failure and persistent pulmonary hypertension of the newborn showed that INO was associated with improvements in oxygenation. There have now been at least 11 prospective randomized controlled trials evaluating the use of INO in the near-term neonate with hypoxic respiratory failure, 10 of which have been published. A meta-analysis of these trials provides evidence that INO improved the PaO2 in the INO treated infants by 46.4 torr (weighted mean difference) compared with controls (95% CI, 34.2, 58.5) and significantly decreased the oxygenation index by 10.7 compared with controls (95% CI, -14.1, -7.4). The incidence of death or need for extracorporeal membrane oxygenation (ECMO) was significantly reduced by treatment with INO, relative risk (RR) 0.72 compared to control (95% CI, 0.6, 0.87) with the majority of the improvement seen in the reduction in the need for ECMO. Infants with congenital diaphragmatic hernia do not appear to benefit from early INO therapy. The only prospective trials evaluating INO in premature infants to date have not found that this therapy is associated with significant clinical benefit. The long-term evaluations of near-term and full-term infants who have received INO suggest that this therapy does not increase the incidence of adverse neurodevelopmental sequelae in these high-risk infants. INO is an effective therapy for the hypoxic term neonate and will reduce the occurrence of death or the need for ECMO in this population. Further research is required to evaluate the benefit of this therapy in the hypoxic preterm infant.

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

BACKGROUND

This section is under preparation and will be included in the next issue.

OBJECTIVES

To determine whether treatment of hypoxemic newborn infants with inhaled nitric oxide (INO) improves oxygenation and reduces the rates of death, or the requirement for ECMO.

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 in term and near term infants. Administration of inhaled nitric oxide. Clinically relevant outcomes, including death, requirement for ECMO, and oxygenation.

DATA COLLECTION AND ANALYSIS

Eight randomized controlled studies were found in term and near term infants with hypoxia. Entry criteria were reasonably consistent except for the one trial that studied only infants with congenital diaphragmatic hernia (Ninos 1997).

MAIN RESULTS

Inhaled nitric oxide appears to improve outcome in hypoxemic 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. It does not appear to affect outcome whether infants have clear echocardiographic evidence of PPHN or not. The outcome of infants with diaphragmatic hernia was not improved; indeed there is a suggestion that outcome was slightly worsened.

REVIEWER'S CONCLUSIONS

On the evidence presently available, it appears reasonable to use inhaled nitric oxide in a concentration of 20 ppm for term and near term infants with hypoxic respiratory failure who do not have a diaphragmatic hernia. Longterm neurodevelopmental and pulmonary followup of surviving infants enrolled in randomized trials of INO are required to establish more firmly the role of INO in the treatment of neonatal respiratory failure.

Infant lung function after inhaled nitric oxide therapy for persistent pulmonary hypertension of the newborn

Our objectives were to determine whether the use of inhaled nitric oxide (iNO) for severe persistent pulmonary hypertension of the newborn (PPHN) causes impaired lung function during infancy. We therefore performed a prospective study of lung function in 22 infants after neonatal intensive care unit (NICU) discharge who had been treated for severe persistent pulmonary hypertension of the newborn (PPHN) with (n = 15) or without (n = 7) iNO, and compared these findings in lung function to those of healthy control infants (n = 18). Five infants with interstitial lung disease (ILD) were included to assure that the pulmonary function tests (PFT) were sensitive enough to detect abnormalities of lung function in this age group. We measured passive respiratory mechanics and functional residual capacity (FRC) using a commercially available system. All data were expressed as means and standard deviation. Statistical analysis was performed by analysis of variance (ANOVA). A Bonferroni multiple comparisons test was used for variables that showed overall group differences. Twenty-two infants were studied during follow-up 4-12 months after NICU discharge. None of the infants were actuely ill, and only one infant was on 0.25 L of oxygen per minute at the time of study. We found no differences in lung function between the treatment groups (iNO + mechanical ventilation (MV), or MV alone), or between either treatment group and healthy control infants of the same age. We were able to detect significant differences in functional residual capacity adjusted for weight or height, and compliance of the respiratory system adjusted for weight or lung volume in the ILD infants compared to the healthy controls or infants who had PPHN, indicating that these PFTs were sensitive enough to determine abnormal lung function in this age group. We conclude that inhaled nitric oxide therapy for the treatment of severe PPHN does not alter lung function as determined by lung volume and passive respiratory mechanics measurements during early infancy.

Recognition and management of pulmonary hypertension

Pulmonary hypertension (mean pulmonary arterial pressure > 20mm Hg at rest or > 30mm Hg during exercise) occurs (i) as primary pulmonary hypertension (no known underlying cause), (ii) as persistent pulmonary hypertension of the newborn or (iii) secondary to a variety of lung and cardiovascular diseases. In the last 10 to 15 years there have been significant advances in the medical management of this debilitating and life-threatening disorder. The main drugs in current use are anticoagulants (warfarin, heparin) and vasodilators, especially oral calcium antagonists, intravenous prostacyclin (prostaglandin I2; epoprostenol) and inhaled nitric oxide. Calcium antagonists, (e.g. nifedipine, diltiazem) are used chiefly in primary pulmonary hypertension. They are effective in patients who give a pulmonary vasodilator response to an acute challenge with a short acting vasodilator (e.g. prostacyclin, nitric oxide or adenosine), and are used in doses greater than are usual in the treatment of other cardiovascular disorders. Prostacyclin, given by continuous intravenous infusion, is effective in patients even if they do not respond to an acute vasodilator challenge. The long term benefit in these patients is thought to reflect the antiproliferative effects of the drug and/or its ability to inhibit platelet aggregation. It is used either as long term therapy or as a bridge to transplantation. Inhaled nitric oxide, which is used mainly in persistent pulmonary hypertension of the newborn, has the particular benefit of being pulmonary selective, due to its route of administration and rapid inactivation. Anticoagulants have a specific role in the treatment of pulmonary thromboembolic pulmonary hypertension and are also used routinely in patients with primary pulmonary hypertension. Nondrug treatments for pulmonary hypertension include (i) supplemental oxygen (> or = 15 h/day), which is the primary therapy in patients with pulmonary hypertension secondary to chronic obstructive pulmonary disease and (ii) heart-lung or lung transplantation, which nowadays is regarded as a last resort. Different types of pulmonary hypertension require different treatment strategies. Future advances in the treatment of pulmonary hypertension may come from the use of drug combinations, the development of new drugs, such as endothelin antagonists, nitric oxide donors and potassium channel openers, or the application of gene therapy.

The outcome of very low birth weight neonates (</=1500 g) rescued by inhaled nitric oxide: neurodevelopment in early childhood

Although inhaled nitric oxide (INO) improves oxygenation in critically ill neonates, the neurodevelopmental outcome of premature neonates with severe hypoxemic respiratory failure treated with INO has not been reported. Mortality and prospective neurodevelopmental assessment in early childhood were studied in a cohort of 24 very low birth weight neonates (</=1500 g) consecutively admitted from 1993 to 1997 and rescued with INO because of severe hypoxemic respiratory failure (oxygenation index 28 to 52) unresponsive to aggressive conventional treatment. Significant improvements in arterial oxygen tension and oxygenation index with lower inspired oxygen concentration and less ventilator support after initiating INO were observed (P <.05, analysis of variance). Despite the dramatic improvement in systemic oxygenation, the mortality rate was high (14 of 24, 58%). Only 6 of 23 had normal cranial ultrasonographies. At 13 to 40 (22 +/- 10) months of adjusted age, 10 survivors had Bayley Scales mental and psychomotor developmental indexes of 81 +/- 21 and 64 +/- 22, respectively. Of the 10 children, 5 (50%) were disabled, 2 (20%) were developmentally delayed, and 3 (30%) had normal development. In view of the poor outcome in very low-birth-weight neonates rescued by INO, randomized controlled trials are required to examine the role of INO in premature neonates. Before, during, and after INO therapy, cranial ultrasonography is recommended.

Cardiac surgery and inhaled nitric oxide: indication and follow-up (2-4 years)

We studied the effect of inhaled nitric oxide (NO) on 80 patients who had undergone cardiac surgery in our center. The indications for receiving NO inhalation and the number of patients were as follows: Pp/Ps > 0.5 for pulmonary hypertension (PH) (n = 32; 21 children and 11 adults), severe PH crisis (n = 9), high pulmonary vascular tone (Glenn pressure more than 18 mm Hg after bidirectional Glenn operation) or arterial oxygen saturation (SaO2) less than 70% despite an FiO2 of 1.0 after Blalock-Taussig shunt (n = 6), mean pulmonary artery pressure (PAP) > 15 mm Hg and transpulmonary gradient (TPG) (mean PAP - left atrial pressure [LAP]) > 8 mm Hg after Fontan-type operation (n = 18), elevated pulmonary vascular tone (mean PAP > 30 mm Hg and left ventricular assist system [LVAS] flow rate < 2.5 L/min/m2) in patients with LVAS (n = 3), and impaired oxygenation (PaO2/FiO2 < 100 under positive end-expiratory pressure [PEEP] > 5 cm H2O) (n = 12). Low dose inhaled NO (10 ppm) had the following effects. In adult PH patients, it significantly reduced the mean PAP (from 37.3 to 27.0 mm Hg; average values are given) and increased the mean systemic arterial pressure (SAP) (64.7 to 75.3 mm Hg). In infant PH patients, it increased the mean SAP (51.8 to 56.1 mm Hg). In patients with a PH crisis, it significantly reduced the central venous pressure (CVP) (13.3 to 8.8 mm Hg) while increasing both the mean SAP (49.4 to 57.9 mm Hg) and PaO2/FiO2 (135 to 206). In patients after a Fontan-type operation, it significantly reduced the mean PAP (16.8 to 13.8 mm Hg) and TPG (9.5 to 5.8 mm Hg). In patients under LVAS, it reduced the CVP (11.7 to 8.0 mm Hg) and mean PAP (32.0 to 24.7 mm Hg). In impaired oxygenation patients, PaO2/FiO2 was increased (75 to 106). Sixty-five patients were all followed for 2.0-4.3 years (average, 3.1 years). All 65 patients remained free from oxygen requirement, and possible chronic adverse effects including the occurrence of malignant tumors or chronic inflammation in the respiratory tract were not observed.

Advances in neonatal care and surgery

Neonatology has seen many advances over the past decade. Exogenous surfactant therapy is now a mainstay treatment for respiratory distress syndrome. Partial liquid ventilation, high-frequency ventilation, and inhaled nitric oxide are all relatively new modalities, which have enabled neonatologists to treat with varying degrees of success ever younger and smaller patients. The purpose of this review is to examine studies regarding the long-term outcome of high-risk neonates, the various treatment modalities, and current neonatal surgical techniques, all of which will influence our care of the neonate.