Decision-making for extremely preterm infants with severe hemorrhages on head ultrasound: Science, values, and communication skills

Severe intracranial hemorrhages are not rare in extremely preterm infants. They occur early, generally when babies require life-sustaining interventions. This may lead to ethical discussions and decision-making about levels of care. Prognosis is variable and depends on the extent, location, and laterality of the lesions, and, importantly also on the subsequent occurrence of other clinical complications or progressive ventricular dilatation. Decision-making should depend on prognosis and parental values. This article will review prognosis and the uncertainty of outcomes for different lesions and provide an outline of ways to conduct an ethically appropriate discussion on the decision of whether to continue life sustaining therapy. It is possible to communicate in a compassionate and honest way with parents and engage in decision-making, focussing on personalized information and decisions, and on function, as opposed to diagnosis.

A tiny baby intubation team improves endotracheal intubation success rate but decreases residents' training opportunities

OBJECTIVE

To assess the educational and clinical impact of a tiny baby intubation team (TBIT).

STUDY DESIGN

Retrospective study comparing endotracheal intubation (ETI) performed: pre-implementation of a TBIT (T1), 6 months post-implementation (T2), and 4 years post-implementation (T3).

RESULTS

Post-implementation (T2), first-attempt success rate in tiny babies increased (44% T1; 59% T2, p = 0.04; 56% T3, p = NS) and the proportion of ETIs performed by residents decreased (53% T1; 37% T2, p = 0.001; 45% T3, p = NS). After an educational quality improvement intervention (prioritizing non-tiny baby ETIs to residents, systematic simulation training and ETI using videolaryngoscopy), in T3 residents' overall (67% T1; 60% T2, p = NS; 79% T3, p = 0.02) and non-tiny baby ETI success rate improved (72% T1; 60% T2, p = NS; 82% T3, p = 0.02).

CONCLUSION

A TBIT improves success rate of ETIs in ELBW infants but decreases educational exposure of residents. Educational strategies may help maintain resident procedural competency without impacting on quality of care.

Neonates with hypoxic-ischemic encephalopathy treated with hypothermia: Observations in a large Canadian population and determinants of death and/or brain injury

BACKGROUND

Birth asphyxia in term neonates remains a serious condition that causes significant mortality and long-term neurodevelopmental sequelae despite hypothermia treatment. The objective of this study was to review therapeutic hypothermia practices in a large population of neonates with hypoxic-ischemic encephalopathy (HIE) across Canada and to identify determinants of adverse outcome.

METHODS

Our retrospective observational cohort study examined neonates≥36 weeks, admitted to the Canadian Neonatal Network NICUs between 2010 and 2014, diagnosed with HIE, and treated with hypothermia. Adverse outcome was defined as death and/or brain injury. Maternal, birth, and postnatal characteristics were compared between neonates with adverse outcome and those without. The association between the variables which were significantly different (p < 0.05) between the two groups and adverse outcome were further tested, while adjusting for gestational age, birth weight, gender, and initial severity of encephalopathy.

RESULTS

A total of 2187 neonates were admitted for HIE; 52% were treated with hypothermia and 40% developed adverse outcome. Initial severity of encephalopathy (moderate, p = 0.006; severe, p < 0.0001), hypotension treated with inotropes (p = 0.001), and renal failure (p = 0.007) were significantly associated with an increased risk of death and/or brain injury.

CONCLUSIONS

In asphyxiated neonates treated with hypothermia, not only their initial severity of encephalopathy on admission, but also their cardiac and renal complications during the first days after birth were significantly associated with risk of death and/or brain injury. Careful monitoring and cautious management of these complications is warranted.

Norepinephrine infusion improves haemodynamics in the preterm infants during septic shock

AIM

This study evaluated the clinical and haemodynamic effects of norepinephrine infusion in preterm infants.

METHODS

The effects of norepinephrine therapy for refractory hypotension were evaluated in preterm infants between April 2009 and April 2011 at the neonatal intensive care unit of Sainte-Justine Hospital, Montreal, Quebec. Changes in haemodynamics and clinical parameters were analysed eight hours before and eight hours after the start of norepinephrine infusion, and eight hours after its cessation.

RESULTS

During the study, 30 preterm infants at a mean gestational age of 26.5 ± 2.6 weeks (median: 25.7, 23.4-34) and birthweight of 903 ± 437 g (median 827, 450-2550) received norepinephrine infusion for neonatal septic shock. After eight hours of treatment, mean blood pressure, urine output and FiO₂ significantly improved. Eight hours after cessation of norepinephrine infusion, the number of patients treated with other inotropes decreased significantly, 24 patients (80%) had normal mean blood pressure and 27 patients (90%) had normal urine output.

CONCLUSION

Norepinephrine therapy could be considered to improve blood pressure and urine output during neonatal septic shock in preterm infants. Further studies are needed to prove the efficacy and safety of norepinephrine infusion in neonates.

Preventing postnatal growth restriction in infants with birthweight less than 1300 g

AIM

To examine nutritional and growth outcomes in very preterm infants with a birthweight (BW) of ≤1300 g before and after the introduction of enhanced enteral and parenteral nutrition protocols.

METHODS

A comparison of two historical cohorts.

RESULTS

There were 153 infants in cohort 1 and 118 in cohort 2. A total of 19% were growth restricted at birth in both cohorts. Feeds advanced more quickly in cohort 2, with decreased duration of central lines and TPN; breastmilk fortification occurred sooner. Calorie and protein intakes were increased during all of the first 14 days of life. Adverse clinical outcomes were unchanged, including NEC. The proportion of infants discharged <10th percentile of expected weight, decreased from 23% to 9%. In cohort 2, the z-score for body weight decreased by 0.39, compared to an average 1.03 in cohort 1 (p < 0.001). Head circumference and body weight were also significantly improved at discharge (p < 0.01), but length was improved to a lesser degree.

CONCLUSION

Early and enhanced postnatal intravenous and enteral feeding can provide good postnatal growth among very immature infants without adverse effects. Calorie and particularly protein intake in early life could probably be further optimised.

Management of hypotension in preterm infants (The HIP Trial): a randomised controlled trial of hypotension management in extremely low gestational age newborns

BACKGROUND

Extremely preterm babies (delivered at <28 completed weeks of gestation) are frequently diagnosed with hypotension and treated with inotropic and pressor drugs in the immediate postnatal period. Dopamine is the most commonly used first-line drug. Babies who are treated for hypotension more frequently sustain brain injury, have long-term disability or die compared to those who are not. Despite the widespread use of drugs to treat hypotension in such infants, evidence for efficacy is lacking, and the effect of these agents on long-term outcomes is unknown.

HYPOTHESIS

In extremely preterm babies, restricting the use of dopamine when mean blood pressure (BP) values fall below a nominal threshold and using clinical criteria to determine escalation of support ('restricted' approach) will result in improved neonatal and longer-term developmental outcomes. RESEARCH PLAN: In an international multi-centre randomised trial, 830 infants born at <28 weeks of gestation, and within 72 h of birth, will be allocated to 1 of 2 alternative treatment options (dopamine vs. restricted approach) to determine the better strategy for the management of BP, using a conventional threshold to commence treatment. The first co-primary outcome of survival without brain injury will be determined at 36 weeks' postmenstrual age and the second co-primary outcome (survival without neurodevelopmental disability) will be assessed at 2 years of age, corrected for prematurity.

DISCUSSION

It is essential that appropriately designed trials be performed to define the most appropriate management strategies for managing low BP in extremely preterm babies.

Intestinal absorption of lipid emulsion in premature infants: a pilot study

BACKGROUND

Adequate nutritional intake is essential in the very-low-birth-weight infant, but difficult to achieve in the first few postnatal days. Can lipids be given enterally in the first few days of life in sick preterm infants?

OBJECTIVE

To determine tolerance and absorption of lipid emulsion when fed enterally to very-low-birth-weight infants.

DESIGN/METHODS

Infants had a birth weight <1,500 g, an appropriate weight for gestational age, and were receiving parenteral nutrition. We performed a progressive series of studies, enrolling 5 infants in each group. Group 1 infants were fed enteral lipid emulsion at 1 g/kg/day for 4 days, starting when 60 ml/kg/day of breast milk was tolerated enterally. Simultaneously, a matched control group which received no oral lipid emulsion was enrolled. We then enrolled group 2 infants who were fed 3 g/kg/day with the same protocol as group 1. Group 3 infants were fed enteral lipid emulsion starting in the first 72 h of life. The infants were fed 1, 2 and 3 g/kg/day subsequently for 48 h each. Fat absorption was measured.

RESULTS

Gestational age was 24.6-30.8 weeks and birth weight was 620-1,400 g. One infant (group 1) developed necrotizing enterocolitis 1 week after the study. There were no other adverse clinical findings. On average, enteral lipid emulsion was started on day 8 of life in groups 1 and 2, and on day 2 in group 3. The intestinal lipid absorption was 93.6% (min. = 76%). There was no difference in fat absorption between the 4 groups (p > 0.05).

CONCLUSIONS

Lipid emulsions are an isotonic high-calorie source which can be given safely enterally instead of intravenously in the immediate neonatal period of very-low-birth-weight infants without clinical adverse effects and with almost complete absorption. There are potential advantages to oral administration of a lipid emulsion starting in early life which require further investigation.

Permissive hypotension in the extremely low birthweight infant with signs of good perfusion

INTRODUCTION

Many practitioners routinely treat infants whose mean arterial blood pressure in mm Hg is less than their gestational age in weeks (GA).

OBJECTIVE

To assess the effectiveness of utilising a combined approach of clinical signs, metabolic acidosis and absolute blood pressure (BP) values when deciding to treat hypotension in the extremely low birthweight (ELBW) infant.

METHODS

Retrospective cohort study of all live born ELBW infants admitted to our neonatal intensive care unit over a 4-year period. Patients were grouped as either normotensive (BP never less than GA), hypotensive and not treated (BP<GA but signs of good perfusion; we termed this permissive hypotension) and hypotensive treated (BP<GA with signs of poor perfusion).

RESULTS

118 patients were admitted during this period. Blood pressure data were available on 108 patients. 53% of patients were hypotensive (mean BP in mm Hg less than GA in weeks). Treated patients had lower birth weight and GA, and significantly lower blood pressure at 6, 12, 18 and 24 h. Normotensive patients and patients designated as having permissive hypotension had similar outcomes. Mean blood pressure in the permissive group increased from 26 mm Hg at 6 h to 31 mm Hg at 24 h. In a logistic regression model, treated hypotension is independently associated with mortality, odds ratio 8.0 (95% CI 2.3 to 28, p<0.001).

CONCLUSIONS

Blood pressure spontaneously improves in ELBW infants during the first 24 h. Infants hypotensive on GA criteria but with clinical evidence of good perfusion had as good an outcome as normotensive patients. Treated low blood pressure was associated with adverse outcome.

Evaluation and treatment of hypotension in the preterm infant

A large proportion of very preterm infants receive treatment for hypotension. The definition of hypotension is unclear, and, currently, there is no evidence that treating it improves outcomes or, indeed, which treatment to choose among the available alternatives. Assessment of circulatory adequacy of the preterm infant requires a careful clinical assessment and may also require ancillary investigations. The most commonly used interventions, fluid boluses and dopamine, are problematic: fluid boluses are statistically associated with worse clinical outcomes and may not even increase blood pressure, whereas dopamine increases blood pressure mostly by causing vasoconstriction and may decrease perfusion. For neither intervention is there any reliable data showing clinical benefit. Prospective trials of intervention for hypotension and circulatory compromise are urgently required.

Management of respiratory failure in the preterm infant

Respiratory failure is common in the preterm infant. Support of the infant with oxygen, positive pressure, and assisted ventilation are among the commonest interventions required in neonatal care. This article is an overview of many features of respiratory care of the preterm infant, including the goals of therapy, continuous positive airways pressure (CPAP), non-invasive ventilation, various modes of ''conventional'' ventilation, high frequency ventilation and inhaled nitric oxide use. The proven benefits and limitations of various interventions are discussed, and areas requiring further investigation are highlighted. Although it is clear that respiratory support is life-saving, there is a lack of good evidence to choose one mode of support over another. Many prospective trials have been performed which, in general, have failed to demonstrate a significant additional benefit of any newer mode of ventilation over conventional time-cycled pressure limited ventilation. Many of the currently available modes of respiratory support have never been subjected to adequate study. Newer modes of respiratory support including such innovations as volume targeted ventilation, pressure support ventilation, and inhaled nitric oxide use in the preterm, require further investigation prior to their adoption for routine clinical use.

Caregivers attitudes for very premature infants: what if they knew?

BACKGROUND

Decisions about resuscitation of extremely premature babies are controversial. Such decisions may reflect poor understanding of outcomes.

OBJECTIVE

To compare caregivers' attitudes towards the resuscitation of a premature infant if they are only told the infant's gestational age or if they are only given prognostic information for infants at that gestational age.

DESIGN/METHODS

Residents and nurses involved in perinatal care were asked whether they would resuscitate a depressed AGA 24-week gestation infant at birth. In another question they were asked whether they would resuscitate a depressed preterm infant with a 50% chance of survival, knowing that of those who survived, 50% would have a development 'within normal limits', 20-25% a serious handicap and 40% with behavioural and/or learning disability.

RESULTS

Two hundred and seventy-nine caregivers responded (91% response rate). In the scenario that only presented gestational age, 21% of respondents would resuscitate. In the scenario that only presented prognostic statistics, 51% of respondents would resuscitate (p<0.05).

CONCLUSIONS

Providers of perinatal health care respond to vignettes differently depending upon the format in which information is provided. The relative unwillingness to resuscitate a baby of 24-week gestation is surprising since outcomes for such babies are the same or better than those we described in the scenario that provided only outcome data without specifying gestational age. Two explanations are possible: (1) respondents have irrational negative associations with low gestational ages or (2) respondents are unaware of actual outcomes.

Treating hypotension in the preterm infant: when and with what: a critical and systematic review

A very large proportion of extremely preterm infants receive treatments for hypotension. There are, however, marked variations in indications for treatment, and in the interventions used, between neonatal intensive care units and between neonatologists.

METHODS

We performed systematic reviews of the literature in order to determine which preterm infants may benefit from treatment with interventions to elevate blood pressure (BP), and which interventions improve clinically important outcomes.

RESULTS

Our review was not able to define a threshold BP that was significantly predictive of a poor outcome, nor whether any interventions for hypotensive infants improved outcomes, nor which interventions were more likely to be beneficial.

CONCLUSIONS

There is a distinct lack of prospective research of this issue, which prevents good clinical care. It is possible that a simple BP threshold that indicates the need for therapy does not exist, and other factors, such as the clinical status or systemic blood flow measurements, may be much more informative. Such a paradigm shift will also require careful prospective study.

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.

Moral distress in the neonatal intensive care unit: caregiver's experience

BACKGROUND

The Neonatal Intensive Care Unit (NICU) can be ethically charged, which can create challenges for health-care workers.

OBJECTIVE

To determine the frequency with which nurses and residents have experienced ethical confrontations and what factors are associated with increased frequency.

DESIGN/METHODS

An anonymous questionnaire was distributed to nurses in a university center, a high-risk obstetric service, a maternity hospital NICU with 85% in-born patients and an outborn NICU, most of whose preterm admissions are those with surgical complications. Obstetric and pediatric residents in the four universities of the province also received the questionnaire, which included demographics, opinions regarding the gestational age threshold at which resuscitation of a premature infant with bradycardia was appropriate, knowledge of cerebral palsy (CP) outcomes (as an indicator of knowledge about long-term sequelae of prematurity) and questions about ethical confrontation in the NICU.

RESULTS

Two hundred and seventy-nine caregivers participated (115 full time nurses and 164 residents). All the distributed questionnaires were completed. Frequent ethical confrontation was reported by 35% of the nurses and 19% of the residents. Among the nurses, moral distress differed significantly between work environments. Nurses working in an out-born NICU and obstetric nurses were more likely to overestimate CP prevalence (P<0.05). Nurses who overestimated CP rates had higher thresholds for resuscitation and were more likely to experience ethical confrontations. Of the residents, 60% were pediatric and 40% obstetric. All groups of residents frequently overestimated the prevalence of CP, and knowledge differed significantly by residency program (P<0.05). The residents who overestimated CP rates had higher thresholds for resuscitation, had more incorrect answers regarding prematurity outcomes and were less likely to have ethical confrontations.

CONCLUSIONS

A large proportion of nurses and residents report frequent ethical confrontations. Many residents and nurses have limited knowledge of outcomes and high threshold for resuscitation. Ethical confrontation is more common among nurses with poor knowledge about outcomes, and less common in residents with poor knowledge about outcomes.

Diagnostic criteria and therapeutic interventions for the hypotensive very low birth weight infant

INTRODUCTION

The diagnosis and management of hypotension in the very low birth weight (VLBW) is a controversial area.

OBJECTIVE

To establish if there is any consensus in the diagnostic criteria and therapeutic interventions in the hypotensive VLBW among neonatologists in Canada.

METHODS

A postal questionnaire was sent to neonatologists in all level II and III neonatal intensive care units throughout Canada.

RESULTS

In total, 120 questionnaires were sent. Ninety-five completed questionnaires were returned. Seventy-six percent of respondents work in units where at least 50 VLBWs and 43% where at least 100 VLBWs are cared for annually. Fifty-seven percent of the respondents have at least 10 years experience as practicing neonatologists. 25.8% rely on blood pressure values alone when intervening, the most common being a blood pressure less than gestational age in weeks. Ninety-seven percent of respondents commence therapy with a fluid bolus. Normal saline is the predominant volume administered (95%). Dopamine remains the pressor of choice. Great variation exists in starting doses and total amount administered. Similar variation exists with epinephrine, with tenfold differences in starting doses (0.01-0.1 mcg/kg/min) and tenfold differences in maximum dose (0.4-4 mc/kg/min) administered. Steroid doses used ranged from 0.1 mg/kg/dose of hydrocortisone to 5 mg/kg/dose. Bicarbonate is rarely used. Three predominant therapeutic regimes exist. These include (i) volume followed by dopamine then a steroid (32%), (ii) volume, dopamine, dobutamine (29%), (iii) volume, dopamine, epinephrine (22%).

CONCLUSION

This is the first large study of practices among neonatologists addressing hypotension in the VLBW infant. There is wide variation in practice, which is a reflection of the lack of good evidence currently available for this very common problem.

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.

Facilitation of neonatal endotracheal intubation with mivacurium and fentanyl in the neonatal intensive care unit

BACKGROUND

Endotracheal intubation in the neonate is painful and is associated with adverse physiological effects. Some premedication regimens have been shown to reduce these effects, but the optimal regimen is not yet determined.

METHOD

Data on semi-elective intubations were prospectively collected in the neonatal intensive care unit over a six month period. Patients received 20 microg/kg atropine, 200 microg/kg mivacurium (a non-depolarising muscle relaxant) followed by 5 microg/kg fentanyl.

RESULTS

Thirty three patients were electively intubated during this time period. The primary reason for intubation was surfactant administration (53%). Median (range) birth weight, gestational age, and age at intubation were 1360 g (675-4200), 29 weeks (25-38), and 33 hours (1-624) respectively. Twenty two of the infants were intubated on the first attempt. Median duration from initial insertion of the laryngoscope to successful intubation was 60 seconds (15 seconds to 20 minutes). In 18 cases, the first attempt was by a trainee with no previous successful intubation experience, 10 of whom intubated within two attempts. Muscle relaxation occurred at a mean (SD) of 94 (51) seconds, and mean (range) time to return of spontaneous movements was 937 seconds (480-1800). Intubation conditions were scored as excellent using a validated intubation scale.

CONCLUSION

Effective analgesia can be administered and intubation performed with some brief desaturations, even when junior personnel are being taught their first intubation. In this first report of mivacurium for intubation in the newborn, effective bag and mask ventilation was easily achieved during muscle relaxation and was associated with excellent intubation conditions, permitting a high success rate for inexperienced personnel.

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.

Sequential analysis for quality control in the neonatal intensive care unit

OBJECTIVE

This article describes a novel application of a statistical technique for continuous quality assurance in the NICU.

METHODS

We used prospective analysis of rates of survival to 28 days of life, without major IVH in ELBW infants in a single tertiary NICU, before and after the introduction of an evidence-based treatment protocol. By using the CUSUM function, each infant's results were sequentially plotted, and significant changes in outcomes were noted when the plot crossed predetermined boundary lines.

RESULTS

Significant changes in outcomes were evident with this method sooner than traditional analyses on the basis of year-end or other arbitrary intervals. The introduction of the ELBW protocol was temporally associated with significant improvement in intact short-term survival.

CONCLUSION

Sequential analysis techniques are useful tools for ongoing quality assurance; deviations in outcomes may be detected more quickly, which should assist in the identification of improvements or decrements in performance of the NICU.

Randomized, prospective study of low-dose versus high-dose inhaled nitric oxide in the neonate with hypoxic respiratory failure

OBJECTIVE

There is little information on the response to very low doses of inhaled nitric oxide (iNO) in hypoxic near-term infants. The potential toxicities of iNO are dose related; thus, the ability to use lower doses safely and effectively may be advantageous. We hypothesized that there is no difference in the acute improvement in oxygenation between treatment with inhaled nitric oxide at 1 to 2 parts per million (ppm) or 10 to 20 ppm.

METHODS

We randomized near-term and term infants with hypoxic respiratory failure with oxygenation indices (OIs) of >/=10 and PaO(2) <100 on 2 separate blood gases taken at least 30 minutes apart. Infants with congenital diaphragmatic hernia were excluded. After parental consent was obtained, patients were randomized to receive a starting nitric oxide (iNO) dose of either 1 to 2 ppm (low-dose group, n = 15) or 10 to 20 ppm (high-dose group, n = 21). The response to iNO was assessed according to the increase in arterial PaO(2) and decrease in OI 30 to 60 minutes after exposure to the initial starting concentration. A response of <10% increase on PaO(2) and a <10% decrease in OI resulted in a doubling of iNO within the dose range protocol (1, 2, 4, and 8 ppm for the low-dose group; 10, 20, 40, and 80 ppm for the high-dose group).

RESULTS

Thirty minutes after the study gas was initiated, PaO(2) increased significantly overall in the low-dose (90.7 +/- 41 torr to 166.8 +/- 95.6 torr) and high-dose (76.2 +/- 32.7 torr to 198.7 +/- 142.8 torr) groups; the maximal increase was seen in the infants who initially were treated with 10 ppm. The OI also decreased significantly overall and also was significant in the high-dose group (21.0 +/- 13.7 to 11.4 +/- 10.4; low-dose: 18.3 +/- 7.1 to 13.2 +/- 12.3). There was a nonsignificant fall of PaCO(2) with iNO treatment (low dose 35 +/- 7.3 to 30 +/- 8.5 torr vs high dose 35.2 +/- 9.9 to 32.4 +/- 10.7 torr). A sustained response (ie, maintaining a PaO(2) and OI gain greater than 20% for the duration of the study gas administration) was greater in the high-dose group (53.3% vs 30.0%). In addition, dose increases were required more often in the low-dose group than in the high-dose group (80.0% vs 57.1%). Among patients who did not respond to the initial iNO dose, 100.0% and 83.3% responded at higher doses of iNO for the low- and high-dose groups, respectively. There were no differences for death, need for extracorporeal membrane oxygenation, or other outcomes between the groups.

CONCLUSIONS

We did not find any significant difference in response to low- versus high-dose iNO. An initial exposure to low-dose iNO does not compromise the response to higher doses if required and may result in less toxicity.

TBC3711, an ET(A) receptor antagonist, reduces neonatal hypoxia-induced pulmonary hypertension in piglets

The pulmonary vasculature of newborns with persistent pulmonary hypertension is characterized by active vasoconstriction and vascular remodeling. It has been suggested that endothelin-1 (ET-1), a potent vasoconstrictor and growth promoter, may be involved in the pathogenesis of persistent pulmonary hypertension of the newborn. To determine whether treatment with an ET(A) receptor antagonist can reverse pulmonary hypertension in the neonate, 1-d-old piglets were exposed to hypoxia for 3 d to induce pulmonary hypertension and then treated for the remainder of the 14 d with an orally active, nonpeptidic ET(A) antagonist (TBC3711, 22 mg x kg(-1) x d(-1)). At the end of the exposure, Hb, pulmonary artery pressure, right ventricle to left ventricle plus septum weight ratio, percentage wall thickness, ET-1 circulating levels, perfusion pressure, and dilator response to the nitric oxide (NO) donor, SIN-1 (3-morpholinosydnonimine-N-ethylcarbamide) in isolated perfused lungs were determined. Exhaled NO and hemodynamic variables were also examined in an intact anesthetized animal preparation that had undergone the same treatment. By 3 d of exposure to hypoxia, piglets had already developed significant pulmonary hypertension as estimated by their pulmonary artery pressure (24.0 +/- 1.3 mm Hg versus 14.2 +/- 3.4 mm Hg) and percentage wall thickness (26.6 +/- 5.9% versus 18.7 +/- 2.4% for vessels 0-30 microm). Whereas further exposure to hypoxia for 14 d did not enhance the increase in pulmonary artery pressure and percentage wall thickness, it did augment the right ventricle to left ventricle plus septum weight ratio (0.71 +/- 0.09 versus 0.35 +/- 0.01). ET-1 circulating levels were increased only when exposure to hypoxia was prolonged to 14 d (5.1 +/- 2.4 pg/mL versus 1.0 +/- 0.4 pg/mL). Treatment with TBC3711 from d 3 to d 14, once pulmonary hypertensive changes were established and while hypoxic exposure persisted, caused significant reduction in the right ventricle to left ventricle plus septum weight ratio (0.60 +/- 0.06), pulmonary artery pressure (20.0 +/- 4.8 mm Hg), and percentage wall thickness (18.5 +/- 3.3%) and restored the dilator response to the NO donor SIN-1. Prolonged hypoxia markedly reduced exhaled NO concentrations (0.3 +/- 0.6 ppb), although treatment of hypoxic animals with TBC3711 restored the concentration of exhaled NO (4.4 +/- 2.8 ppb) to the level of normoxic controls (4.9 +/- 3.0 ppb). Lastly, treatment with TBC3711 increased ET-1 circulating levels in both the normoxic (5.4 +/- 2.8 pg/mL) and hypoxic (13.0 +/- 6.3 pg/mL) groups. In conclusion, the specific ET(A) receptor antagonist, TBC3711, can significantly ameliorate the morphologic changes encountered in hypoxia-induced pulmonary hypertension in the newborn piglet and may improve the dilator response to NO.

Intravenous lipid composition affects hypoxic pulmonary vasoconstriction in the newborn piglet

To examine the effects of altering the fatty acid (FA) composition of intravenous (IV) lipid emulsions on pulmonary vascular resistance (PVR) and thromboxane production, we studied three groups of newborn piglets after three days of either sow's milk (milk), or total parenteral nutrition (TPN) with either iv soy bean oil (SBO, 52% n-6 and 8% n-3 FA) or fish oil (FO, 5% n-6 and 51% n-3 FA) emulsions. At baseline, and during hypoxia at 20 min and 2 h, cardiac output (Q) was measured, PVR calculated and plasma levels of a prostacyclin metabolite (6-keto-PgF1alpha) and thromboxane B2 (TxB2) were measured. Fatty acid composition of the lung phospholipids was analyzed. There was an exaggerated increase in PVR and decrease in Q during prolonged hypoxia in the TPN-SBO group as compared with the other two groups. There was no difference in PVR and Q between the milk and TPN-FO groups. FA of lung phospholipids reflected the high dietary level of long chain n-3 FA in the TPN-FO group. However, no differences in plasma levels of 6-keto-PgF1alpha or TxB2 were found. Intravenous emulsions made from SBO reduced cardiac output and increased pulmonary vascular resistance in the hypoxic newborn piglet, whereas iv FO emulsions did not. When subjects with pulmonary hypertension are receiving TPN iv SBO may be detrimental; iv FO may be beneficial, giving similar responses as in a milk-fed subject.

Randomized trial of nasal synchronized intermittent mandatory ventilation compared with continuous positive airway pressure after extubation of very low birth weight infants

OBJECTIVE

To determine whether noninvasive, nasal synchronized intermittent mandatory ventilation (nSIMV) improves the likelihood that very low birth weight infants will be successfully extubated.

METHODS

Infants of <1251-g birth weight who were due to be extubated before 6 weeks of age were eligible once they were receiving <35% oxygen and were on a ventilator rate of <18 breaths per minute (bpm). Extubation was performed following intravenous loading with aminophylline, after a successful trial of 12 hours of endotracheal synchronized intermittent mandatory ventilation at a rate of 8. Infants were randomized to either nasal continuous positive airway pressure (nCPAP) at 6 cm H(2)O or nSIMV after extubation. nSIMV was commenced at a rate of 12 bpm with pressure on the ventilator set to achieve a delivered pressure of at least 12 cm H(2)O and a peak end expiratory pressure of 6 cm H(2)O. Continuous recording for diagnosis of apnea was performed for 72 hours after extubation. Objective criteria for failure of extubation were as follows: a PaCO(2) >70; FIO(2) >0.7; or severe recurrent apnea (>2 apneas requiring intermittent positive-pressure ventilation in 24 hours or >6 apneas >20 seconds per day). The study ended after 72 hours postextubation or when infants satisfied failure criteria. A sample size of 54 was determined by power analysis.

RESULTS

Mean birth weight (831 standard deviation [SD]: 193 g) and gestation (26.3 SD: 1.8 weeks) did not differ between groups. Mean age at extubation was 7.6 (SD: 9.7) days, range 1 to 40 days. The nSIMV group had a lower incidence of failed extubation 4/27 compared with the continuous positive airway pressure group, 12/27. This was attributable to both a decreased incidence of apnea and a decreased incidence of hypercarbia. There was no increase in the incidence of abdominal distension or feeding intolerance.

DISCUSSION

nSIMV is effective in preventing extubation failure in very low birth weight infants in the first 72 hours after extubation. Noninvasive ventilation may have other roles in the care of the very low birth weight infant.

The adverse neuro-developmental effects of postnatal steroids in the preterm infant: a systematic review of RCTs

BACKGROUND

Recent reports have raised concerns that postnatal steroids may cause neuro-developmental impairment in preterm infants. This systematic review was performed with the objective of determining whether glucocorticoid therapy, to prevent or treat bronchopulmonary dysplasia, impairs neuro-developmental outcomes in preterm infants.

METHOD

A systematic review of the literature was performed. Medline was searched and articles retrieved using predefined criteria. Data from randomized controlled trials with adequate neuro-developmental follow up (to at least one year) were entered into a meta-analysis to determine the effects of postnatal treatment of preterm infants with glucocorticoids. Cerebral palsy rates, and neuro-developmental impairment (developmental score more than 2SD below the mean, or cerebral palsy or blindness) were analyzed. The studies were divided into 2 groups according to the extent of contamination of the results by treatment of controls with steroids after the initial study period, those with less than 30% contamination, and those with more than 30% contamination or size of contamination not reported.

RESULTS

Postnatal steroid therapy is associated with an increase in cerebral palsy and neuro-developmental impairment. The studies with less contamination show a greater effect of the steroids, consistent with a real direct toxic effect of steroids on the developing central nervous system. The typical relative risk for the development of cerebral palsy derived from studies with less than 30% contamination is 2.86 (95% CI 1.95, 4.19). The typical relative risk for the development of neuro-developmental disability among followed up infants from studies with less than 30% contamination is 1.66 (95% CI 1.26, 2.19). From this subgroup of studies, the number of premature infants who need to be treated to have one more infant with cerebral palsy (number needed to harm, NNH) is 7; to have one more infant with neuro-developmental impairment the NNH is 11.

CONCLUSIONS

Postnatal pharmacologic steroid treatment for prevention or treatment of bronchopulmonary dysplasia is associated with dramatic increases in neuro-developmental impairment. As there is no clear evidence in the literature of long term benefit, their use for this indication should be abandoned.

Effects of a continuous epinephrine infusion on regional blood flow in awake newborn piglets

OBJECTIVE

To determine the effects of a continuous epinephrine infusion on renal and mesenteric blood flow in both healthy newborn piglets and animals subjected to hemorrhagic shock.

METHODS

Superior mesenteric artery (SMA) and left renal artery ultrasonic flow probes were implanted into 16 1- to 3-day-old piglets. Two days later, the effects of epinephrine on SMA and renal blood flow, mean arterial pressure (MAP) and central venous pressure were measured in conscious, non-sedated normovolemic piglets. Epinephrine doses of 0.2, 0.4, 0.8, 1.6 and 3.2 microg/kg.min were used in random order. Piglets were subsequently hemorrhaged (20 ml/kg) to mild hypotension and again received epinephrine infusion in the same doses.

RESULTS

Doses of epinephrine less than 3.2 microg/kg.min had no significant effects on renal or mesenteric arterial flow. At 3.2 microg/kg.min of epinephrine during normovolemia, there was a significant decrease in SMA blood flow (34% [SD 42], p < 0.05) and increase in SMA vascular resistance (147% [SD 114], p < 0.05). Similar results were shown during hypovolemia, SMA flow decreased by 32% (SD 33), and SMA vascular resistance increased by 220.3% (SD 177). At 3.2 microg/kg.min renal artery flow decreased by 43% (SD 21) during normovolemia and a similar decrease occurred during hypovolemia, 37% (SD 31). Renal vascular resistance increased by about 200% at this dose (normovolemia 211% [SD 185], hypovolemia 186% [SD 150], p < 0.01). Low-to-moderate dose epinephrine caused no significant change in SMA or renal blood flow. During hypovolemia low dose epinephrine infusion was associated with a trend to increased SMA blood flow.

CONCLUSION

Low-dose epinephrine does not cause vasoconstriction in the renal or mesenteric circulations during normovolemia or hypovolemia. High doses of epinephrine above 1.6 microg/kg.min may cause renal or mesenteric ischemia, in either the normovolemic or hypovolemic neonate.

Effects of magnesium sulfate in a newborn piglet meconium aspiration model

OBJECTIVE

To examine the hemodynamic effects of magnesium sulfate (MgSO4) in a neonatal model of meconium aspiration syndrome.

DESIGN

A prospective animal study.

PATIENTS AND PARTICIPANTS

Eight anesthetized neonatal piglets.

METHODS

Animals were instrumented under fentanyl anesthesia for the determination of pulmonary and systemic blood pressures and cardiac index. A model of meconium aspiration was produced by instilling 6 to 7 ml of 20% fresh human meconium in normal saline down the endotracheal tube, resulting in hypoxemia (mean arterial O2 saturation 73 SD, 10%), respiratory acidosis (mean pH 7.08, SD 0.04; PaCO2 89, SD 2 torr), and pulmonary arterial hypertension (mean pulmonary artery pressure 52 SD, 5 mm Hg). A total of four aliquots of MgSO4 (25 mg/kg equivalent to 0.1 mM/kg of magnesium) were administered intravenously to five animals (total of 100 mg/kg MgSO4). Three animals served as controls and did not receive MgSO4.

RESULTS

Each dose of MgSO4 was associated with a transient decrease in heart rate, cardiac index, pulmonary and systemic arterial pressures, and SaO2, followed by a partial gradual recovery of all these variables within 2 to 3 minutes. According to measurements taken after MgSO4 therapy, there was a significant decrease in arterial saturations (from 73 SD (10%) to 63 SD (13%); p < 0.05), mean systemic blood pressure (from 77 SD (16 mm Hg) to 74 SD (15 mm Hg); p < 0.05) and pulmonary artery pressure (to 52 SD (5 mm Hg); p < 0.05). The ratio between pulmonary and systemic vascular resistance was not significantly affected by MgSO4 therapy. There were no changes in the control animals.

CONCLUSION

The administration of magnesium sulfate is associated with increased hypoxemia in this model of meconium aspiration syndrome, probably because of worsening ventilation perfusion mismatch. These data do not provide any physiological support for the use of MgSO4 in the neonate with meconium aspiration and pulmonary hypertension and suggest that this agent should be used cautiously, if at all, in such situations.

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.

The hemodynamic effects of inhaled nitric oxide and endogenous nitric oxide synthesis blockade in newborn piglets during infusion of heat-killed group B streptococci

OBJECTIVE

To determine the effects of therapy with inhaled nitric oxide (NO) gas and partial or complete blockade of endogenous NO synthesis with N(omega)nitro-L-arginine (L-NA) on the hemodynamic responses to group B streptococci infusion in newborn piglets.

DESIGN

Randomized, acute intervention study.

SETTING

Animal research laboratory.

SUBJECTS

Twenty-five anesthetized piglets younger than 3 days of age divided into five groups.

INTERVENTIONS

Heat-killed group B streptococci (GBS) were infused systemically until a 50% increase in pulmonary artery pressure (PAP) was obtained, and the infusion was continued for another 2 hrs. The five groups were designed as follows: group 1, sepsis control: continuous GBS infusion, with two brief trials (10 mins) of inhaled NO given after the initial development of pulmonary hypertension and again 2 hrs later; group 2, continuous inhaled NO: NO was given at 40 ppm for 2 hrs during GBS infusion; group 3, high-dose L-NA pretreatment: 10 mg/kg L-NA bolus followed by 1 mg/kg/min before, and continuing throughout, GBS infusion; group 4, high-dose L-NA: same dose as in group 3, but given after the start of the GBS infusion with continuous inhaled NO at 40 ppm; and group 5, low-dose L-NA: 3 mg/kg bolus given after start of GBS infusion with continuous inhaled NO at 40 ppm.

MEASUREMENTS AND MAIN RESULTS

The sepsis controls, group 1, had an increase in PAP, which took 15-45 mins to develop, from a mean of 3.4 (SD 0.7) to 5.9 (1.9) kPa (p < .05), at which time the cardiac index had decreased from 169 (28) to 146 (46) mL/kg/min (p < .05). Brief inhaled NO during the early phase decreased PAP to normal. Two hours later, PAP had increased to 6.1 (0.2) kPa and cardiac index had decreased to 88 (31) mL/kg/min. Inhaled NO after 2 hrs decreased PAP to 3.2 (0.5) kPa and increased cardiac index to 106 (44) ml/kg/min (p < .05). Continuous inhaled NO (group 2) ameliorated the deterioration in cardiac index, which at 2 hrs was 140 (30) mL/kg/min (significantly greater than in the sepsis controls) (p < .05). The L-NA-pretreated animals (group 3) had a greater increase in PAP and pulmonary vascular resistance index when GBS infusion was started. PAP increased from 3.0 (0.7) to 7.3 (1.5) kPa within 15 mins, and cardiac index simultaneously decreased to 68 (20) mL/kg/min. Cardiac index subsequently rapidly deteriorated to 48 (21) mL/kg/min, and only one of five animals survived for 2 hrs. Group 4 animals also developed a rapid deterioration in cardiac output, and only two of five survived for 2 hrs. Group 5 animals had results indistinguishable from group 2 animals.

CONCLUSION

Pulmonary hypertension and shock resulting from GBS infusion in newborn piglets are much worse if endogenous NO production is completely inhibited. Continuous inhaled NO with or without low-dose L-NA inhibits the decrease in cardiac output.

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.

Inhaled nitric oxide for respiratory failure in preterm infants

BACKGROUND

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

OBJECTIVES

To determine whether, in preterm newborn infants who have hypoxic respiratory failure, treatment with inhaled nitric oxide improves oxygenation and reduces the rates of death, or adverse neurodevelopmental outcome.

SEARCH STRATEGY

Electronic and hand searching of pediatric/neonatal literature and personal data files.

SELECTION CRITERIA

Randomized and quasi randomized studies in preterm infants with hypoxic respiratory failure. Administration of inhaled nitric oxide. Clinically relevant outcomes, including death, oxygenation, intraventricular haemorrhage.

DATA COLLECTION AND ANALYSIS

One randomized controlled trial of nitric oxide therapy was found in preterm infants with a high risk of developing bronchopulmonary dysplasia (Subhedar 1997).

MAIN RESULTS

No significant effect of inhaled nitric oxide on any outcome variable was found. In particular there was no effect on the primary outcome variable of death or bronchopulmonary dysplasia.

REVIEWER'S CONCLUSIONS

There is currently no published information to support the use of inhaled nitric oxide in preterm infants. Preterm infants should not be treated with inhaled nitric oxide except in the context of prospective, randomized controlled trials.

Umbilical artery catheters in the newborn: effects of heparin

BACKGROUND

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

OBJECTIVES

To determine whether the use of heparin in fluids infused through an umbilical arterial catheter in newborn infants influences the frequency of clinical ischemic events, catheter occlusion, aortic thrombosis, intraventricular hemorrhage, hypertension, death, or the duration of catheter usability.

SEARCH STRATEGY

Randomized and quasi randomized controlled trials of umbilical catheterization use were obtained from the following sources: 1. Effective Care of the Newborn Infant, edited by JC Sinclair and MB Bracken. 2. Medline Search using Melvyl Medline Plus and the keyword headings 'Umbilic#', 'Catheter#' and subject heading 'Infant, Newborn' 3. Search of personal data files

SELECTION CRITERIA

Randomized trials in newborn infants of any birthweight or gestation. Comparison of heparinised to non heparinised infusion fluids, including comparison of heparin in the infusate to heparin just in the flush solution. Clinically important end points such as catheter occlusion or aortic thrombosis.

DATA COLLECTION AND ANALYSIS

There were five randomized controlled trials retrieved. All gave details of the incidence of catheter occlusion. Two also reported the incidence of aortic thrombosis. The intervention was reasonably consistent: heparin in the infusate at a concentration of 1 unit/mL was investigated in all trials except one which used a concentration of 0.25 units/mL. Studies generally included both term and preterm infants.

MAIN RESULTS

Heparinization of the infusate decreases the incidence of catheter occlusion but does not affect the frequency of aortic thrombosis. Heparinization of the flush solution is not an adequate alternative. There does not appear to be an effect on frequency of intraventricular hemorrhage, death or clinical ischemic phenomena.

REVIEWER'S CONCLUSIONS

Heparinization of the fluid infused through an umbilical arterial catheter decreases the likelihood of umbilical arterial catheters occluding. The lowest concentration tested so far (0.25 units/mL) has been shown to be effective. Heparinization of flushes without heparinizing the infusate is ineffective. The frequency of aortic thrombosis has not been shown to be affected; however, the confidence intervals for this effect are very wide. The frequency of intraventricular hemorrhage has not been shown to be affected by heparinization of the infusate, but again the confidence intervals are very wide and even a major increase in the incidence of grade 3 and 4 intraventricular hemorrhage would not have been detected.

Umbilical artery catheters in the newborn: effects of catheter design (end vs side hole)

BACKGROUND

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

OBJECTIVES

To determine whether the design of an umbilical arterial catheter influences the frequency of ischemic events, aortic thrombosis, intraventricular hemorrhage, mortality or necrotising enterocolitis in newborn infants.

SEARCH STRATEGY

Randomized and quasi randomized controlled trials of umbilical catheterization use were obtained from the following sources: 1. Effective Care of the Newborn Infant, edited by JC Sinclair and MB Bracken. 2. Medline Search using Melvyl Medline Plus and the keyword headings 'Umbilic#', 'Catheter#' and subject heading 'Infant, Newborn' 3. Search of personal data files

SELECTION CRITERIA

Randomized trials in newborn infants of any birthweight or gestation. Comparison of end hole catheters with side hole catheters. Clinically important end points such as ischemic events or aortic thrombosis.

DATA COLLECTION AND ANALYSIS

There appears to be only a single trial which has addressed this issue (Wesstrom 1979).

MAIN RESULTS

End hole catheters are associated with a much decreased risk of aortic thrombosis compared to side hole catheters. RR = 0.27 (95% CI 0.11, 0.67)

REVIEWER'S CONCLUSIONS

Side hole catheters should be avoided for umbilical arterial catheterisation in the newborn.

Umbilical artery catheters in the newborn: effects of position of the catheter tip

BACKGROUND

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

OBJECTIVES

To determine whether the position of the tip of an umbilical arterial catheter influences the frequency of ischemic events, aortic thrombosis, intraventricular hemorrhage, mortality or necrotising enterocolitis in newborn infants.

SEARCH STRATEGY

Randomized and quasi randomized controlled trials of umbilical catheterization use were obtained from the following sources: 1. Effective Care of the Newborn Infant, edited by JC Sinclair and MB Bracken. 2. Medline Search using Melvyl Medline Plus and the keyword headings 'Umbilic#', 'Catheter#' and subject heading 'Infant, Newborn' 3. Search of personal data files

SELECTION CRITERIA

Randomized trials in newborn infants of any birthweight or gestation. Comparison of high catheter placement with the tip above the diaphragm to a lower position just above the aortic bifurcation. Clinically important end points such as ischemic events or aortic thrombosis.

DATA COLLECTION AND ANALYSIS

Five randomized controlled trials and one alternate assignment study had sufficiently detailed data to allow interpretation.

MAIN RESULTS

High placed umbilical artery catheters are associated with a lower incidence of clinical vascular complications, without an increase in any adverse sequelae. Intraventricular hemorrhage rates, death and necrotising enterocolitis are not more frequent with high compared to low catheters.

REVIEWER'S CONCLUSIONS

There appears to be no evidence to support the use of low placed umbilical artery catheters. High catheters should be used exclusively.

Vancomycin for prophylaxis against sepsis in preterm neonates

BACKGROUND

Nosocomial, late onset sepsis occurs in up to 50% of infants of less than 1000gm at birth. The commonest organism isolated is coagulase negative staphylococcus (CoNS). A number of studies have evaluated the efficacy or prophylactic low dose vancomycin given either as a continuous infusion added to the infant's hyperalimentation fluid or by intermittent intravenous administration and these studies in very low birth weight infants are the subject of this review.

OBJECTIVES

To evaluate the safety and efficacy of vancomycin prophylaxis for the prevention of late-onset sepsis, coagulase negative staphylococcal sepsis, mortality, and effects on length of stay, total vancomycin exposure, evidence of vancomycin toxicity, and the development of vancomycin resistant organisms in the preterm neonate.

SEARCH STRATEGY

Searches were made of Medline, (MeSH terms: Vancomycin and Sepsis; limits: age groups, newborn infants), HealthStar and EMBase, electronic abstracts, personal files and conference proceedings.

SELECTION CRITERIA

Randomized controlled trials which compared the incidence of sepsis and mortality in preterm neonates receiving vancomycin prophylaxis versus a control group receiving no prophylaxis.

DATA COLLECTION AND ANALYSIS

Data regarding clinical outcomes including the overall incidence of sepsis, the incidence of coagulase negative staphylococcal sepsis, mortality, length of stay, total vancomycin exposure, evidence of vancomycin toxicity, and the development of vancomycin resistant organisms were excerpted from previous clinical trials. Data analysis was done in accordance with the standards of the Cochrane Neonatal Review Group.

MAIN RESULTS

The administration of prophylactic vancomycin reduced the incidence of both total neonatal nosocomial sepsis and coagulase negative staphylococcal sepsis in eligible preterm infants. Mortality, length of stay, and evidence of vancomycin toxicity were not significantly different between the two groups. There was insufficient evidence to ascertain the risks of development of vancomycin resistant organisms in the nurseries involved in these trials.

REVIEWER'S CONCLUSIONS

The use of prophylactic vancomycin in low doses reduces the incidence of nosocomial sepsis in the neonate. The methodologies of these studies may have contributed to the low rate of sepsis in the treated groups, as the blood cultures drawn from central lines may have failed to grow due to the low levels of vancomycin in the infusate. Although there is a theoretical concern regarding the development of resistant organisms with the administration of prophylactic antibiotic, there is insufficient evidence to ascertain the risks of development of vancomycin resistant organisms. Few clinically important benefits have been demonstrated for very low birth weight infants treated with prophylactic vancomycin. It therefore appears that routine prophylaxis with vancomycin should not be undertaken at present.

Umbilical artery catheters in the newborn: effects of catheter materials

BACKGROUND

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

OBJECTIVES

To determine whether the material used for construction of an umbilical arterial catheter influences the frequency of ischemic events, aortic thrombosis, mortality or necrotising enterocolitis in newborn infants.

SEARCH STRATEGY

Randomized and quasi randomized controlled trials of umbilical catheterization use were obtained from the following sources: 1. Effective Care of the Newborn Infant, edited by JC Sinclair and MB Bracken. 2. Medline Search using Melvyl Medline Plus and the keyword headings "Umbilic#", "Catheter#" and subject heading "Infant, Newborn" 3. Search of personal data files

SELECTION CRITERIA

Randomized studies in newborn infants of any birthweight or gestation. Comparison of different catheter materials. Clinically important end points such as ischemic events, aortic thrombosis, or catheter occlusion.

DATA COLLECTION AND ANALYSIS

One non-randomized and one randomized study were retrieved.

MAIN RESULTS

There were no significant effects of substituting a heparin bonded polyurethane catheter for the standard PVC catheter. The non-randomized study suggested that there may possibly be a benefit of using a catheter constructed from Silastic, with a reduction in aortic thrombosis.

REVIEWER'S CONCLUSIONS

There are no demonstrated clinically relevant differences in outcomes between the use of PVC catheters and other materials. Therefore, other considerations such as price and ease of availability may dictate the catheter chosen. An adequately powered randomized comparison of silastic to PVC should be performed.