Parental concerns and vaccine hesitancy against COVID-19 vaccination for children in Greece: A cross-sectional survey

INTRODUCTION

Parental hesitancy against children's COVID-19 vaccination remains a challenge globally. Although many studies have explored parental hesitancy, less is known about parental intentions towards COVID-19 vaccination of 6-month to 4-year-old children who were the last age group that became eligible for vaccination and for older children throughout the Omicron predominance period.

METHODS

We conducted a nationwide cross-sectional survey from November to December 2022 in Greece. We aimed to explore parental COVID-19 vaccination intentions for their children, reasons against vaccination, and to estimate the association between parents' intentions and child and parental characteristics and parental attitudes towards COVID-19 vaccination.

RESULTS

Of 431 parents, 243 (56.4 %) had not or did not intend to vaccinate their children against COVID-19. Most parents were vaccinated against COVID-19 (64.7 % no booster; 14.2 % at least one booster). Among parents with children under the age of 5, 13.0 % intended to vaccinate their children against COVID-19, while 47.3 % of parents with children 5 years of age or older reported intention or had already completed vaccination. The most common reasons against COVID-19 vaccination were fear of side effects (32.9 %), perceived short length of clinical trials (29.2 %), and the child having previously contracted COVID-19 (12.0 %). The strongest factors associated with intention or already completed vaccination were parental own vaccination against COVID-19, using a pediatrician or a healthcare professional as the main source of vaccine-related information for their children, agreeing with their pediatrician regarding COVID-19 vaccination, and trusting official healthcare guidelines. Stratified analyses by the two children's age groups (<5 and 5 to 17) yielded similar estimates. Among parents who had not or did not intend to vaccinate their children, 11.9 % would do so if recommended by a pediatrician.

CONCLUSIONS

Our findings highlight the need to incentivize healthcare professionals and pediatricians to inform parents about vaccines, clarify misconceptions and address concerns.

Impact of COVID-19 vaccination on parental and childhood stress levels in Greece

OBJECTIVE

The impact of COVID-19 vaccination on parental and childhood stress levels has not been thoroughly investigated. Our aim was to explore the above relationship and identify factors that may influence the dissemination of stress within the family during the pandemic.

SUBJECTS AND METHODS

A cross-sectional e-survey was conducted among a nationwide sample of parents in May 2021 in Greece. Parental stress was assessed using the Perceived Stress Scale (PSS) and the Revised Impact of Event Scale (IES-R) tools. Childhood mental well-being was evaluated with the Children's Revised Impact of Event 13 (CRIES 13) scale.

RESULTS

1,703 unique questionnaires were analyzed; 19.5% of responders were completely vaccinated, 23.7% were partially vaccinated, 38.3% were awaiting vaccination, and 18.5% were classified as vaccine-hesitant (15.2% would delay, and 3.3% refused the vaccination). Stress levels were significantly lower in completely or partially vaccinated parents than in vaccine-hesitant ones (p<0.001 for PSS/IES-R). Vaccination status emerged as a strong and independent predictor of PSS and IES-R. A significant decrease in PSS and IES-R scores was observed in 991 participants between March 2020 and May 2021 (p<0.001 for PSS/IES-R). Vaccine uptake was associated with lower PSS and IES-R scores, irrespective of the phase of the pandemic or other sociodemographic factors. The CRIES 13 score of the participant's children (n=2,969) was 19.4 ±14.9 and positively correlated with the PSS and IES-R scores. Children whose parents were vaccinated had lower stress levels than those of vaccine-hesitant parents (p<0.001).

CONCLUSIONS

Parental vaccination against COVID-19 is a significant stress and anxiety predictor for both parents and their offspring. Parental and childhood stress levels were correlated, while the effect of vaccination was independent of the pandemic phase. The campaigns to promote vaccine uptake against COVID-19 should also highlight its potential benefit on the psychological well-being of the family.

Child abuse experience, training, knowledge, and attitude of healthcare professionals in sixty hospitals in Greece

OBJECTIVE

This study aims to record the overall perception of healthcare professionals on child abuse and identify potential affecting factors in a nationwide scale in Greece as well as to provide information that might be useful for future educational actions.

MATERIALS AND METHODS

A total of 1,185 healthcare professionals in 60 hospitals with pediatric departments across Greece participated in this cross-sectional study. Participants included pediatricians, pediatric surgeons, residents, nurses, psychiatrists, psychologists, and social workers. Sections under investigation involved experience and training in child abuse, knowledge of formal and judicial issues, clinical knowledge, and self-assessment.

RESULTS

Although more than half of the participants had confronted child abuse (n=712, 60.08%), only 273 (38.34% of them) submitted reports. One third of participants reported that they had received some training (n=440, 37.13%), mainly of postgraduate nature and based on personal initiative. Of those who reported child abuse, 175 (64.10%) had been trained. Each professional category was aware of topics regarding its own interest, without adequate knowledge of other disciplines. One third of psychiatrists, psychologists, and social workers felt confident in discussing with children and parents. Relevant scores were lower in the other categories. The lower scores were recorded among nurses and residents. The training deficit and reluctance to engage with judicial issues were the main causes of avoidance to deal with child abuse.

CONCLUSIONS

Focused and organized training in child abuse is crucial to create reliable professionals in the field. The internet is a considerably helpful tool. Professionalism must characterize knowledge and practice in child abuse at the same level as in other medical topics. Motivation to engage should be early inspired and developed during the graduate years.

A novel presentation of an ATP1A3 gene mutation - case report and literature review

OBJECTIVE

Mutations in the ATP1A3 gene cause the classical disorders of rapid-onset dystonia-parkinsonism (RDP), alternating hemiplegia of childhood (AHC) and cerebellar ataxia, areflexia, pes cavus, optic atrophy, and sensorineural hearing loss (CAPOS). However, intermediate phenotypes have also been described, making the range of clinical manifestations associated with mutations in the ATP1A3 gene wider. A rare case of an ATP1A3 gene mutation is presented.

CASE REPORT

Genetic testing was performed in a neonate who presented with neurological abnormalities on day 2 of life, severe electrolytic disturbances a few days later and developmental delay and epilepsy a few months later. A pathogenic heterozygous missense mutation in the ATP1A3 gene (c.2482G>A, E828K(p.Glu828Lys) was detected on clinical exome sequencing.

CONCLUSIONS

The present case report extends the already described phenotypic variation observed in individuals with ATP1A3 gene mutations. It also illustrates the importance of genetic testing in the case of complex and not straightforward clinical scenarios, particularly when present from a very young age, before clinical criteria for known diagnoses are met.

Prediction of complicated appendicitis risk in children

OBJECTIVE

We aimed to predict the risk of complicated appendicitis in children, constructing a risk-based prediction tool with the optimal combination of sensitivity and specificity outcomes.

PATIENTS AND METHODS

This is a prospective study on a random sample of children with acute appendicitis who underwent appendectomy. Clinical examination, history, routine laboratory tests, Alvarado and pediatric appendicitis scores, operative and histopathological findings were taken into consideration. The predictive ability of the outcome variables was assessed by the Receiver Operating Characteristics (ROC) analysis. The overall predictive ability and determination of the best cut-off value (the higher sum of sensitivity plus specificity) were calculated. A Classification and Regression Tree (CRT) was used to create a multi-level classification algorithm. The model was set to predict the outcome of complicated appendicitis, considering as potential predictors the demographic characteristics, the clinical findings, and the outcome parameters.

RESULTS

The various combinations of clinical and laboratory parameters did not improve their overall diagnostic ability. However, the CRT analysis resulted in a short classification algorithm based on the Pediatric appendicitis score, neutrophils percentage and the CRP. This model yielded a significantly better predictive ability than all the other combinations of the outcome parameters. The application of the model would predict complicated appendicitis with 90% sensitivity and 78.6% specificity.

CONCLUSIONS

The constructed predictive model may be a useful tool for daily practical use by the clinician, especially in areas where modern diagnostic imaging facilities are absent or not always available. Clinical evaluation and close follow-up remain the more accurate preoperative method to decide the performance and timing of appendectomy.

Vaccination coverage among school children in Western Greece from 2016 to 2019

Vaccine hesitancy has increased, which has an effect on vaccine uptake. The aim of our study was to investigate childhood vaccination coverage in Western Greece and identify factors affecting it. We also aimed to assess trends in childhood vaccination coverage nationwide. A cross-sectional study was conducted (2016-2019) in all the primary schools in Patras, the third largest city in the country. Data collection was undertaken using child vaccination booklets and questionnaires on socio-demographics. Multiple regression analyses were performed to evaluate relevant associations. We also performed a systematic review of published data on childhood vaccination coverage in Greece during the last two decades. Data for 1657 children was collected and 371 questionnaires were returned. High vaccination coverage (>90%) was observed for the majority of the vaccines. For the pneumococcal conjugate vaccine (PCV), coverage with four doses, as recommended at the time of study, was suboptimal (39.2%). For human papillomavirus vaccines and the meningococcal serogroup B vaccine, full vaccination coverage was 2.6% and 6.5%, respectively. No association with socio-demographics was found for vaccines with high coverage. For PCV the number of doses given was related to Greek nationality (β = 0.185, p < .001) and parental employment status (β = -0.115, p = .043). Compared to previous studies (16 eligible), there was a trend toward higher coverage. Public health interventions should focus on increasing vaccine uptake of specific vaccines among populations with particular characteristics. A national network recording vaccine coverage is urgently required in the country to monitor vaccine uptake and assess trends over time.

Is rotation the mode of failure in pertrochanteric fractures fixed with nails? Theoretical approach and illustrative cases

PURPOSE

The present article reviews data from biomechanical and clinical studies which indicate that rotational instability can cause failure of fixation due to the particular characteristics of the fracture, the mechanical properties of the chosen implant or flaws in surgical technique.

METHODS

Although radiographs give a similar impression in failure of fractures fixed with cephalomedullary nails, different mechanisms involving rotation of the femoral head may play a key role.

RESULTS

The incidence of failure in pertrochanteric fracture fixation is decreasing as implants continue to evolve. It is possible that currently reported low failure rates do not apply equally to all subtypes of this diverse group of fractures. Since the introduction of sliding hip screws, "cut-out" due to varus collapse of the proximal fracture fragment has been the only reported mode of failure.

CONCLUSION

Excessive rotation leading to eventual "cut-out" has not been adequately studied, and thus, available evidence is not sufficient to definitely prove this theoretical approach. As nailing is gradually overtaking extramedullary fixation as the treatment of choice, especially for comminuted pertrochanteric fractures which can be rotationally unstable, further research is warranted to improve our understanding of the pathogenetic mechanisms of failure.

Pre-pregnancy maternal obesity in Greece: A case-control analysis

BACKGROUND-AIMS

Pre-pregnancy obesity may cause significant health implications for both mother and neonate. Our study aims to investigate the association between pre-pregnancy Body Mass Index and the risk for cesarean section, admission to Neonatal Intensive Care Unit, macrosomia and preterm delivery, in a Mediterranean country.

STUDY DESIGN

A matched retrospective case control analysis was conducted.

SUBJECTS

The study population included all pregnant women (with known Body Mass Index data) who gave birth in the University Hospital of Patras between 1st of January 2003 and 31st of December 2008.

OUTCOME MEASURES

Cases were defined as obese (338) or overweight (826) women.

RESULTS

Overweight and obese women were at higher risk for cesarean section, NICU admission and preterm delivery (χ(2)(2)=36.877, p<0.001, χ(2) Imes and Burke (2014) =6.586, p=0.037 and χ(2) Imes and Burke (2014) =7.227, p=0.027 respectively). Neonatal mean birthweight was higher among obese and overweight women (p<0.0001).

CONCLUSIONS

Both obese and overweight pregnancies should be considered as high risk pregnancies, due to more frequent adverse pregnancy outcomes (cesarean delivery, preterm delivery and NICU admission).

Pre-pregnancy obesity: maternal, neonatal and childhood outcomes

Nowadays, obesity rates have an increasing tendency, since the incidence of obesity in both developed and developing countries is still rising over the years. Maternal pre-pregnancy obesity seems to have an influence on both obstetrical and neonatal outcomes. Many researchers have focused on pregnancies of obese nulliparous, non diabetic women as well as on the medical profile of their neonates, with conflicting conclusions. Additionally, several studies have followed these neonates through their childhood and adult life in order to observe them for any occurrence towards specific diseases. In our study, literature was reviewed and results are presented, into two groups. The first group summarizes the correlation of high maternal prepregnancy Body Mass Index (BMI) with the rates of hypertensive disorders, fertility, cesarean section and maternal mortality, while the second group correlates maternal BMI to neonatal Apgar score, neonatal admission to NICU, preterm delivery, congenital defects, birthweight, and weight status after birth, child morbidity, respiratory problems as asthma and children's mortality. Maternal pre-pregnancy obesity tends to have an important negative impact on the above mentioned outcomes. However, further research, in certain fields, needs to be carried out in order to gain a clear image.

Synchronized mechanical ventilation for respiratory support in newborn infants

BACKGROUND

During synchronized mechanical ventilation, positive airway pressure and spontaneous inspiration coincide. If synchronous ventilation is provoked, adequate gas exchange should be achieved at lower peak airway pressures, potentially reducing baro/volutrauma, air leak and bronchopulmonary dysplasia. Synchronous ventilation can potentially be achieved by manipulation of rate and inspiratory time during conventional ventilation and employment of patient triggered ventilation.

OBJECTIVES

To compare the efficacy of: (i) synchronized mechanical ventilation, delivered as high frequency positive pressure ventilation (HFPPV) or patient triggered ventilation - assist control ventilation (ACV) or synchronous intermittent mandatory ventilation (SIMV)) with conventional ventilation (CMV) (ii) different types of triggered ventilation (ACV, SIMV, pressure regulated volume control ventilation (PRVCV) and SIMV plus pressure support (PS) SEARCH STRATEGY: Searches from 1985-2007 of the Cochrane Central Register of Controlled Trials (CENTRAL, The Cochrane Library, Issue 2, 2007),Oxford Database of Perinatal Trials, MEDLINE, previous reviews, abstracts and symposia proceedings; hand searches of journals in the English language and contact with expert informants.

SELECTION CRITERIA

Randomised or quasi-randomised clinical trials comparing synchronized ventilation delivered as high frequency positive pressure ventilation (HFPPV) or triggered ventilation (ACV/SIMV) to conventional mechanical ventilation (CMV) in neonates. Randomised trials comparing different triggered ventilation modes (ACV, SIMV, SIMV plus PS and PRVCV) in neonates.

DATA COLLECTION AND ANALYSIS

Data regarding clinical outcomes including mortality, air leaks (pneumothorax or pulmonary interstitial emphysema (PIE)), severe intraventricular haemorrhage (grades 3 and 4), bronchopulmonary dysplasia (BPD) (oxygen dependency beyond 28 days), moderate/severe BPD (oxygen/respiratory support dependency beyond 36 weeks postmenstrual age (PMA) and duration of weaning/ventilation. Four comparisons were made: (i) HFPPV vs. CMV; (ii) ACV/SIMV vs. CMV; (iii) ACV vs. SIMV or PRVCV vs. SIMV (iv) SIMV plus PS vs. SIMV. Data analysis was conducted using relative risk for categorical outcomes, weighted mean difference for outcomes measured on a continuous scale.

MAIN RESULTS

Fourteen studies were eligible for inclusion. The meta-analysis demonstrates that HFPPV compared to CMV was associated with a reduction in the risk of air leak (typical relative risk for pneumothorax was 0.69, 95% CI 0.51, 0.93). ACV/SIMV compared to CMV was associated with a shorter duration of ventilation (weighted mean difference -34.8 hours, 95% CI -62.1, -7.4). ACV compared to SIMV was associated with a trend to a shorter duration of weaning (weighted mean difference -42.4 hours, 95% CI -94.4, 9.6). Neither HFPPV nor triggered ventilation was associated with a significant reduction in the incidence of BPD. There was a non-significant trend towards a lower mortality rate using HFPPV vs. CMV and a non-significant trend towards a higher mortality rate using triggered ventilation vs. CMV. No disadvantage of HFPPV or triggered ventilation was noted regarding other outcomes. Since the last review, two new patient triggered modes have been included: pressure regulated volume control ventilation (PRVCV) and SIMV plus pressure support. Each of these methods of ventilation has only been tested in single randomised trials with no significant advantages in important outcomes.

AUTHORS' CONCLUSIONS

Compared to conventional ventilation, benefit is demonstrated for both HFPPV and triggered ventilation with regard to a reduction in air leak and a shorter duration of ventilation, respectively. In none of the trials was complex respiratory monitoring undertaken and thus it is not possible to conclude that the mechanism of producing those benefits is by provocation of synchronized ventilation. Further trials are needed to determine whether synchronized ventilation is associated with other benefits, but optimisation of trigger and ventilator design with respect to respiratory diagnosis is encouraged before embarking on further trials. It is essential newer forms of triggered ventilation are tested in adequately powered randomised trials with long-term outcomes before they are incorporated into routine clinical practice.

Antenatal steroids and fluid balance in very low birthweight infants

OBJECTIVES

To determine if insensible water loss (IWL) differed between infants exposed or not exposed antenatally to corticosteroids and to explore possible mechanisms for the early postnatal diuresis associated with antenatal steroid exposure.

DESIGN

Retrospective analysis of prospectively collected data.

SETTING

Level three neonatal intensive care unit.

PATIENTS

Ninety six infants, median gestational age 27.5 weeks (range 23-33).

MAIN OUTCOME MEASURES

Comparison of the IWL, urine output and osmolality, fluid input, electrolyte imbalance, respiratory illness severity (as assessed by surfactant requirement, maximum peak inspiratory pressure, and inspired oxygen concentration), and cardiovascular status (as assessed by inotrope requirement) between infants with antenatal corticosteroid exposure and gestational age matched controls.

RESULTS

The infants exposed to antenatal steroids differed significantly from the controls in having both a lower IWL (p = 0.0135) and a higher urine output (p = 0.0036) on day 1, and fewer developed hyponatraemia (p = 0.027) on day 2. Fewer of those exposed to antenatal steroids required inotropes (p = 0.06), but their respiratory status was similar to that of the controls.

CONCLUSIONS

Infants exposed to antenatal corticosteroids have a lower IWL. The results suggest that greater skin maturation, but also better perfusion rather than less severe respiratory status, explains the early diuresis in infants exposed to antenatal steroids.

Synchronized mechanical ventilation for respiratory support in newborn infants

BACKGROUND

During synchronized mechanical ventilation, positive airway pressure and spontaneous inspiration coincide. Thus, if synchronous ventilation is provoked, adequate gas exchange should be achieved at lower peak airway pressures, potentially reducing barotrauma and hence airleak and chronic lung disease. Synchronous ventilation can be achieved by manipulation of rate and inspiratory time during conventional ventilation and employment of patient assisted ventilation.

OBJECTIVES

To compare (i) the efficacy of synchronized mechanical ventilation, delivered as high frequency positive pressure ventilation or triggered ventilation (patient triggered ventilation (PTV) or synchronous intermittent mandatory ventilation (SIMV)) with conventional ventilation(ii) different types of triggered ventilation

SEARCH STRATEGY

Searches from 1985-2004 of the Cochrane Central Register of Controlled Trials (CENTRAL, The Cochrane Library, Issue 3, 2004), Oxford Database of Perinatal Trials, MEDLINE, previous reviews, abstracts and symposia proceedings; hand searches of journals in the English language and contact with expert informants.

SELECTION CRITERIA

Randomized or quasi randomized clinical trials comparing synchronized ventilation delivered as high frequency positive pressure ventilation (HFPPV) or triggered ventilation (PTV/SIMV) to conventional mechanical ventilation (CMV) in neonates. Randomized trials comparing different triggered ventilation modes (PTV and SIMV) in neonates.

DATA COLLECTION AND ANALYSIS

Data regarding clinical outcomes including mortality, airleaks (pneumothorax or pulmonary interstitial emphysema (PIE)), severe intracerebral haemorrhage (grades 3 and 4), chronic lung disease (oxygen dependency beyond 28 days) and duration of weaning/ventilation. Three comparisons were made: (i) HFPPV vs CMV; (ii) PTV/SIMV vs CMV; (iii) PTV vs SIMV. Data analysis was conducted using relative risk for categorical outcomes, weighted mean difference for outcomes measured on a continuous scale.

MAIN RESULTS

Eleven studies were eligible for inclusion. The meta-analysis demonstrate that HFPPV compared to CMV was associated with a reduction in the risk of airleak (typical relative risk for pneumothorax was 0.69, 95% CI 0.51, 0.93). PTV/SIMV compared to CMV was associated with a shorter duration of ventilation (weighted mean difference -34.8 hours, 95% CI -62.1, -7.4). PTV compared to SIMV was associated with a trend to a shorter duration of weaning (weighted mean difference -42.4 hours, 95% CI -94.4, 9.6). Neither HFPPV nor triggered ventilation was associated with a significant reduction in the incidence of chronic lung disease. There was a non-significant trend towards a lower mortality rate using HFPPV versus CMV, but a non-significant trend towards a higher mortality rate using triggered ventilation versus CMV. No disadvantage of HFPPV or triggered ventilation was noted regarding other outcomes.

REVIEWERS' CONCLUSIONS

Compared to conventional ventilation, benefit is demonstrated for both HFPPV and triggered ventilation with regard to a reduction in airleak and a shorter duration of ventilation, respectively. In none of the trials was complex respiratory monitoring undertaken and thus it is not possible to conclude that the mechanism of producing those benefits is by provocation of synchronized ventilation. Further trials are needed to determine whether synchronized ventilation is associated with other benefits, but optimization of trigger and ventilator design with respect to respiratory diagnosis is encouraged before embarking on further trials.

Lung volume and the response to high volume strategy, high frequency oscillation

BACKGROUND

Infants with severe respiratory failure are frequently transferred to high volume strategy, high frequency oscillation (HFO). Mean airway pressure (MAP) is then elevated, the aim being to open up atelectatic lungs and hence improve gas exchange.

AIM

To test the hypothesis that lung volume prior to transfer would predict the response to high volume strategy HFO and identify which factors related to poor outcome (death).

METHODS

Lung volume was assessed by measurement of functional residual capacity (FRC) and the response to HFO determined by the change in the alveolar arterial gradient (AaDO2) on transfer from conventional mechanical ventilation (CMV) to the optimal MAP on high volume strategy HFO.

PATIENTS

Forty-two infants with a median gestational age of 28 (range 23 to 40) wk were studied.

RESULTS

FRC prior to transfer correlated significantly with the change in MAP necessary to optimize oxygenation (p = 0.012), but not the change in AaDO2 in response to HFO. There were no significant differences in the lung volumes of survivors and non-survivors, but those who died were more immature (p = 0.0009) and had a smaller response to HFO (p = 0.035).

CONCLUSION

Lung volume prior to transfer to high volume strategy HFO might be helpful to guide oscillatory settings, but is a poor predictor of the response to high volume strategy HFO.

Effect of posture on oxygenation and respiratory muscle strength in convalescent infants

OBJECTIVE

To determine if differences in respiratory muscle strength could explain any posture related effects on oxygenation in convalescent neonates.

METHODS

Infants were examined in three postures: supine, supine with head up tilt of 45 degrees, and prone. A subsequent study was performed to determine the influence of head position in the supine posture. In each posture/head position, oxygen saturation (SaO2) was determined and respiratory muscle strength assessed by measurement of the maximum inspiratory pressure (PIMAX).

PATIENTS

Twenty infants, median gestational age 34.5 weeks (range 25-43), and 10 infants, median gestational age 33 weeks (range 30-36), were entered into the first and second study respectively.

RESULTS

Oxygenation was higher in the prone and supine with 45 degrees head up tilt postures than in the supine posture (p<0.001), whereas PIMAX was higher in the supine and supine with head up tilt of 45 degrees postures than in the prone posture (p<0.001). Head position did not influence the effect of posture on PIMAX or oxygenation.

CONCLUSION

Superior oxygenation in the prone posture in convalescent infants was not explained by greater respiratory muscle strength, as this was superior in the supine posture.

Metabolic acidosis, core-peripheral temperature difference and blood pressure response to albumin infusion in hypotensive, very premature infants

The aim of this study was to assess if albumin infusion in hypotensive, preterm infants improved blood pressure (BP), metabolic acidosis and core peripheral temperature difference, indicating that such infants had been hypovolemic. Thirty-seven infants, median gestational age 27 weeks (range 23-34) were studied. Their mean BP, core-peripheral temperature difference, pH and base deficit prior to and post albumin infusion were compared. Albumin infusion was associated with BP elevation (p < 0.01) and a small reduction in the base deficit (p < 0.01), but no significant changes overall in the pH or peripheral core temperature difference. Similar results were seen if only 34 infants less than or equal to 4 days of age treated for their first episode of hypotension were considered, although in that group there was also a modest rise in pH (p < 0.02). These data suggest clinically relevant hypovolemia is uncommon in hypotensive, preterm ventilated infants and hence volume expanders are inappropriate routine first therapy.

Prediction of extubation failure in preterm infants

OBJECTIVE

To identify whether the results of assessment of respiratory muscle strength or respiratory load were better predictors of extubation failure in preterm infants than readily available clinical data.

PATIENTS

Thirty six infants, median gestational age 31 (range 25-36) weeks and postnatal age 3 (1-14) days; 13 were < 30 weeks of gestational age.

METHODS

Respiratory muscle strength was assessed by measurement of maximum inspiratory pressure generated during airway occlusion, and inspiratory load was assessed by measurement of compliance of the respiratory system.

RESULTS

Overall, seven infants failed extubation-that is, they required reintubation within 48 hours. These infants were older (p < 0.01), had a lower gestational age (p < 0.01), and generated lower maximum inspiratory pressure (p < 0.05) than the rest of the cohort. Similar results were found in the infants < 30 weeks of gestational age. Overall and in those < 30 weeks of gestational age, gestational age and postnatal age had the largest areas under the receiver operator characteristic curves.

CONCLUSION

In very premature infants, low gestational age and older postnatal age are better predictors of extubation failure than assessment of respiratory muscle strength or respiratory load.

Effect of maturity on maximal transdiaphragmatic pressure in infants during crying

The aim of this study was to determine the effect of maturation on diaphragmatic function. In addition, we investigated whether noninvasive assessment yielded similar results to invasive measurement. Twenty-eight infants, median gestational age (GA) 35.5 wk (range, 25 to 42 wk) and postconceptional age (PCA), 37.6 wk (range, 32 to 44 wk), were examined. Diaphragmatic function was assessed by measuring the maximal transdiaphragmatic pressure during crying (cPdi) using balloon catheters in the midesophagus (Pes) and the stomach (Pgas). In 14 of the infants, a noninvasive measurement of inspiratory muscle strength, maximal inspiratory pressure (PImax), was also made. cPdi and PImax were recorded during a crying effort with the airway occluded at end-expiration. The median cPdi and Pes during crying (cPes), but not Pgas during crying (cPgas), were significantly lower in those studied at a PCA of less than term compared with those studied at an older age (p < 0.05). cPdi and cPes, but not cPgas, correlated significantly with PCA (r = 0.44, p < 0.02; r = 0.43, p < 0.03; respectively) and gestational age (r = 0.46, p < 0.02 and r = 0.56, p < 0.01; respectively). In the 14 infants, the median PImax was lower, but it correlated significantly with cPdi (r = 0.79, p < 0.01). We conclude maturation does affect diaphragm function, and PImax may provide a noninvasive index of diaphragm strength.

Comparison of airway pressure and airflow triggering systems using a single type of neonatal ventilator

The performances of two triggering systems using a single neonatal ventilator type (SLE) were compared. Eight infants, gestational age 27-30 wk, were each recorded during two 1-h periods of patient-triggered ventilation (PTVs), one with airway pressure and one with airflow triggering. The airflow trigger had a shorter trigger delay (p < 0.02), higher sensitivity (p < 0.02) and lower asynchrony rate (p < 0.02).

CONCLUSION

In immature infants with mild respiratory distress syndrome using the SLE ventilator with inflation times of 0.3 to 0.36 sec, airflow triggering is more appropriate than airway pressure triggering.

Routine daily chest radiographs in ventilated, very low birth weight infants

The aim of this study was to assess the frequency of new abnormalities on routine chest radiographs of ventilated, very low birth weight (VLBW) infants during the acute stage of their illness. Infants were identified who had had at least three daily routine chest radiographs. The appearance of their subsequent radiographs was compared to that obtained on the 1st day of ventilatory support and the timing of new abnormalities (malposition of the endotracheal or nasogastric tube, pulmonary interstitial emphysema, pleural effusion, pulmonary oedema, lobar collapse or consolidation) noted. A total of 100 radiographs were examined from 30 VLBW infants, median gestational age 27 weeks (range 23-32 weeks). New abnormalities were present on the radiographs of 24 infants and on 50% of the radiographs examined. The commonest abnormalities noted were pulmonary interstitial emphysema, collapse and consolidation. Conclusion. Routine daily chest radiographs in mechanically ventilated, very low birth weight infants during the acute stage of their respiratory illness can yield new information important in patient care, new abnormalities being demonstrated in 50% of radiographs examined.

Assessment of neonatal diaphragm function using magnetic stimulation of the phrenic nerves

A nonvolitional test to assess diaphragm strength in neonates has not been previously described. Our aim was to assess the feasibility of cervical (CMS) and anterior (AMS) magnetic stimulation of the phrenic nerves in neonates. Double circular stimulating coils (90-mm) were used. For CMS, one coil was placed over the cervical spine to bilaterally stimulate the phrenic nerve roots, whereas for AMS the coils were placed on the anterolateral aspect of the neck to allow unilateral and bilateral stimulation. Diaphragm contractility was assessed as transdiaphragmatic pressure (Pdi) measured with balloon catheters positioned in the midesophagus and stomach. Stimulus supramaximality was assessed by examining diaphragm twitch Pdi (TwPdi) across a range of stimulator outputs; 85, 90, 95, and 100% of maximum. Pressure signals were measured by differential pressure transducer and displayed in real time on a computer. Patients were studied supine during sleep. CMS was performed on seven neonates (mean gestational age [GA] 38 wk, range 33 to 40 wk) and AMS on 18 neonates (mean GA 37 wk, range 32 to 41 wk). The mean (SD) TwPdi with CMS was 2.5 (0.8) cm H(2)O. CMS was not supramaximal; reducing the stimulator output below 100% caused marked reductions in TwPdi, also the shape of the pressure waveforms suggested that CMS may not have activated the diaphragm alone. Mean (SD) TwPdi with AMS was 4.5 (1.3) cm H(2)O on the left, 4.1 (0.9) cm H(2)O on the right, and 8.7 (3.9) cm H(2)O for bilateral stimulation. The shape of the pressure waveforms suggested that AMS was more specific and a plateau in TwPdi at higher stimulator outputs indicated supramaximality. We conclude that AMS may provide a useful technique to assess diaphragm function in the neonate.

A comparison of arginine vasopressin levels and fluid balance in the perinatal period in infants who did and did not develop chronic oxygen dependency

Arginine vasopressin (AVP) levels on days 1, 3 and 5 and fluid balance in the perinatal period were assessed in 60 infants, median gestational age 27 weeks (range 24-33). Fluid input and output, urine osmolality and episodes of hyponatraemia were recorded on a daily basis. Forty-one infants subsequently developed chronic lung disease (CLD), they were more immature, of lower birthweight and had higher AVP levels on days 3 and 5 (p < 0.05) than the rest of the cohort. Despite similar levels of fluid input, compared to the non-CLD infants, those who developed CLD had higher urine osmolalities on days 1, 5, 6 and 7 (p < 0.05), but there were not significant differences between the two groups regarding urine output or episodes of hyponatraemia. Logistic regression analysis revealed AVP levels on day 3 were significantly correlated with the duration of oxygen dependency independent of other factors. We conclude elevated AVP levels in the perinatal period are associated with CLD development, but our results suggest they have little functional significance.

Randomised trial of fluid restriction in ventilated very low birthweight infants

BACKGROUND

Fluid restriction has been reported to improve survival of infants without chronic lung disease (CLD), but it remains unknown whether it reduces CLD in a population at high risk of CLD routinely exposed to antenatal steroids and postnatal surfactant without increasing other adverse outcomes.

AIM

To investigate the impact of fluid restriction on the outcome of ventilated, very low birthweight infants.

STUDY DESIGN

A randomised trial of two fluid input levels in the perinatal period was performed. A total of 168 ventilated infants (median gestational age 27 weeks (range 23-33)) were randomly assigned to receive standard volumes of fluid (60 ml/kg on day 1 progressing to 150 ml/kg on day 7) or be restricted to about 80% of standard input.

RESULTS

Similar proportions of infants on the two regimens had CLD beyond 28 days (56% v 51%) and 36 weeks post conceptional age (26% v 25%), survived without oxygen dependency at 28 days (31% v 27%) and 36 weeks post conceptional age (58% v 52%), and developed acute renal failure. There were no statistically significant differences between other outcomes, except that fewer of the restricted group (19% v 43%) required postnatal steroids (p < 0.01). In the trial population overall, duration of oxygen dependency related significantly to the colloid (p < 0.01), but not crystalloid, input level; after adjustment for specified covariates, the hazard ratio was 1.07 (95% confidence interval 1.02 to 1.13).

CONCLUSIONS

In ventilated, very low birthweight infants, fluid restriction in the perinatal period neither reduces CLD nor increases other adverse outcomes. Colloid infusion, however, is associated with increased duration of oxygen dependency.

Elective use of nasal continuous positive airways pressure following extubation of preterm infants

The aim of this study was to determine whether elective use of nasal continuous positive airways pressure (CPAP) following extubation of preterm infants was well tolerated and improved short- and long-term outcomes. A randomized comparison of nasal CPAP to headbox oxygen was undertaken and a meta-analysis performed including similar randomized trials involving premature infants less than 28 days of age. A total of 150 infants (median gestational age 30 weeks, range 24-34 weeks) were randomized in two centres. Fifteen nasal CPAP infants and 25 headbox infants required increased respiratory support post-extubation and 15 nasal CPAP infants and nine headbox infants required reintubation (non significant). Eight infants became intolerant of CPAP and were changed to headbox oxygen within 48 h of extubation; 19 headbox infants developed apnoeas and respiratory acidosis requiring rescue nasal CPAP, 3 ultimately were re-intubated. Seven other trials were identified, giving a total number of 569 infants. Overall, nasal CPAP significantly reduced the need for increased respiratory support (relative risk, 0.57, 95% CI 0.43-0.73), but not for re-intubation (relative risk 0.89, 95% CI 0.68-1.17). Nasal CPAP neither influenced significantly the intraventricular haemorrhage rate reported in four studies (relative risk 1.0, 95% CI 0.55, 1.82) nor that of oxygen dependency at 28 days reported in six studies (relative risk 1.0, 95% CI 0.8, 1.25). In two studies nasal CPAP had to be discontinued in 10% of infants either because of intolerance or hyperoxia.

CONCLUSION

Elective use of nasal continuous positive airways pressure post-extubation is not universally tolerated, but does reduce the need for additional support.

Evidence to suggest that the phosphodiesterase 4 isoenzyme is present and involved in the proliferation of umbilical cord blood mononuclear cells

BACKGROUND

The type 4 phosphodiesterase (PDE) isoenzyme is the main isoenzyme of PDE involved in the control of adult mononuclear cell proliferation.

OBJECTIVE

To establish whether PDE isoenzymes are present in umbilical cord blood mononuclear cells by the use of selective PDE inhibitors, and to identify which PDE isoenzymes are involved in controlling the proliferation of cord blood mononuclear cells.

METHODS

Cord blood was obtained from normal deliveries and mononuclear cells isolated as described previously [1] with some modifications. Mononuclear cells were then stimulated to proliferate with phytohaemagglutinin (PHA) (2 microg/mL) in the presence of selective PDE inhibitors. Proliferation was measured by [3H]-thymidine incorporation.

RESULTS

The type 4 PDE inhibitors (CDP840, rolipram and RO 20-1724), and the mixed PDE3/4 inhibitor, zardaverine, produced a concentration-related inhibition of PHA-stimulated cord blood mononuclear cell proliferation (P < 0.05, ANOVA). The non-selective PDE inhibitor, theophylline, also produced a concentration-related inhibition of proliferation (P < 0.05, ANOVA). In contrast, the PDE1 inhibitor, vinpocetine, the PDE3 inhibitor, siguazodan, and the PDE5 inhibitor, zaprinast, were unable to inhibit cord blood mononuclear cell proliferation.

CONCLUSION

PDE4 is present in umbilical cord mononuclear cells and is involved in the control of cord blood mononuclear cell proliferation.

Respiratory distress in a neonate with an enlarged thymus

Thymic hyperplasia, although not a rare condition in infancy, is usually asymptomatic. We describe an infant presenting in the perinatal period with marked tachypnoea. An enlarged thymus, demonstrated on chest radiograph and CT, was associated with small-volume, non-compliant lungs. Other causes of pulmonary malfunction and maldevelopment were excluded.

CONCLUSION

Thymic enlargement is unusually associated with neonatal respiratory distress but should be considered in the differential diagnosis.

The chest radiograph appearances of very premature infants at 36 weeks post-conceptional age

The chest radiograph of very premature infants at 36 weeks post-conceptional age (PCA) was evaluated with regard to the degree of hyperinflation and cardiomegaly, and the presence of fibrosis/interstitial shadowing, cystic elements, air bronchograms and opacification. The evolution of abnormalities was assessed by comparing the radiograph appearance at 36 weeks PCA with that at 28 days post-natal age (PNA). Three scoring systems were used to determine how any abnormalities present could be best quantified to reflect disease severity as determined by chronic dependency upon supplementary oxygen status. Chest radiographs at 36 weeks PCA from 60 infants (median gestational age 26 weeks (range 24-28)) were studied. 47 infants also had radiographs at 28 days PNA. Only three infants had no chest radiograph abnormalities at 36 weeks PCA, although 24 infants were not dependent upon supplementary oxygen. The most common abnormalities were interstitial shadowing and hyperinflation, while cystic elements and cardiomegaly were rare. The radiographic appearance had deteriorated from 28 days PNA to 36 weeks PCA (p < 0.05); more infants at 36 weeks PCA were hyperinflated (p < 0.01). The chest radiograph appearances of infants who were dependent upon supplementary oxygen scored higher than those who were not (p < 0.01) using all three scoring systems. The system that assessed only the presence of interstitial shadowing, cystic elements and hyperinflation had the highest specificity in identifying oxygen dependency beyond 36 weeks PCA and had the highest area under the respective receiver operator characteristic curve. In conclusion, the majority of very immature infants have an abnormal chest radiograph appearance at 36 weeks PCA. The appearance can, however, be meaningfully scored by evaluating only three abnormalities.

Effect on lung function of continuous positive airway pressure administered either by infant flow driver or a single nasal prong

The aim of this study was to assess if continuous positive airways pressure (CPAP) delivered by an infant flow driver (IFD) was a more effective method of improving lung function than delivering CPAP by a single nasal prong. A total of 36 infants (median gestational age 29 weeks, range 25-35 weeks) were studied, 12 who received CPAP via an IFD, 12 who received CPAP via a single nasal prong and 12 without CPAP. CPAP was administered post extubation if apnoeas and bradycardias or a respiratory acidosis developed or electively if the infant was of birth weight <1.0 kg. Lung function was assessed by the supplementary oxygen requirement and measurement of compliance of the respiratory system using an occlusion technique. Assessments were made immediately prior to and after 24 h of CPAP administration and at similar postnatal ages in the non-CPAP group. The infants who did not require CPAP had better lung function (non significant) than the other two groups before they received CPAP. After 24 h, lung function had improved in both CPAP groups to the level of the non CPAP infants. The supplementary oxygen requirements of all three groups decreased over the 24 h period, but this only reached significance in the single nasal prong group (P<0.05). Four infants supported by the IFD, but none with a single nasal prong, became hyperoxic.

CONCLUSION

Continuous positive airways pressure administration via the infant flow driver appears to offer no short-term advantage over a single nasal prong system when used after extubation in preterm infants.

Prediction of extubation failure in preterm neonates

The aim of this study was to compare the results of lung function measurements made before and after extubation and ventilator settings recorded immediately prior to extubation with regard to their ability to predict extubation success in mechanically ventilated, prematurely born infants. Immediately after extubation all infants were nursed in an appropriate amount of humidified oxygen bled into a headbox. Functional residual capacity, spontaneous tidal volume and compliance of the respiratory system were measured both within 4 h before and within 24 h after extubation. The peak inspiratory pressure and inspired oxygen concentration immediately prior to extubation were recorded. The results were related to extubation failure: requirement for continuous positive airways pressure or re-ventilation within 48 h of extubation. A total of 30 infants, median gestational age 29 weeks (range 25-33 weeks) were studied at a median postnatal age of 3 days (range 1-6 days). Extubation failed in ten infants, who differed significantly from the rest of the cohort with regard to their post extubation functional residual capacity (FRC) (median 23, range 15.6-28.7 ml/kg versus 28.6, range 18.1-39.2 ml/kg, P<0.01) and their requirement for a higher inspired oxygen concentration post extubation (median 0.30, range 0.21-0.40 versus 0.22, range 0.21-0.36, P<0.05). An FRC of less than 26 ml/kg post extubation had the highest positive predictive value in predicting extubation failure.

CONCLUSION

A low lung volume performed best in predicting extubation failure when compared to the results of other lung function measurements and commonly used 'clinical' indices, i.e. ventilator settings. A low gestational age, however, was a better predictor of extubation failure than a low lung volume.

Prediction of outcome by computer-assisted analysis of lung area on the chest radiograph of infants with congenital diaphragmatic hernia

BACKGROUND/PURPOSE

Pulmonary hypoplasia is a major cause of mortality and morbidity in infants with congenital diaphragmatic hernia (CDH). Pulmonary hypoplasia is characterized by low volume lungs, and affected infants are likely to have a low lung area on their chest radiograph. The authors assessed whether, in CDH infants, computer-assisted analysis of the chest radiograph lung area gave an accurate indication of lung volume, and if a low lung area was a better predictor of poor outcome (death or oxygen dependency at 28 days) than other test results.

METHODS

Comparisons were made of the radiographic lung area derived by computer-assisted analysis and lung volume, assessed by measurement of functional residual capacity (FRC) on day 1 before surgical intervention and on the first postoperative day. Compliance was measured, and the maximum and modified ventilation indices and maximum Paco2 also was noted. Twenty-five CDH infants with a median gestational age of 38 weeks were studied; 18 had FRC measurements preoperatively.

RESULTS

Both preoperatively and postoperatively, the lung areas and FRCs correlated significantly (r = 0.51, P<.05; r = 0.76, P<.02, respectively). Eleven infants had a poor outcome (5 infants died without an operation); that group preoperatively differed significantly from those with a good outcome with respect to having a lower compliance (P<.02) and higher maximum ventilation index (P<.01) and maximum modified ventilation index (P<.05). Only postoperatively did infants with a poor outcome versus good outcome have a significantly lower lung area (P<.05); they also had a lower increase in lung area preoperatively to postoperatively (P<.01). Receiver operator characteristic curves were constructed; comparison of the areas under the curves showed that preoperatively, a low compliance and high ventilation index were the best predictors of poor outcome. Postoperatively, a low lung area performed as well as the ventilation indices.

CONCLUSION

Computer-assisted analysis of the lung area on the chest radiograph is useful in predicting outcome in CDH infants postoperatively but not preoperatively.

Randomized trial of two levels of fluid input in the perinatal period--effect on fluid balance, electrolyte and metabolic disturbances in ventilated VLBW infants

The aim of this study was to determine whether fluid restriction does indeed significantly increase acute adverse effects. One-hundred-and-sixty-eight ventilated infants, median gestational age 27 wk (range 23-33) and birthweight 953 g (range 486-1500), entered into a randomized controlled trial of two fluid regimes. Infants on regime A were to be prescribed 60 ml/kg of fluids on day 1 which was gradually increased over the first week to 150 ml/kg, infants on fluid regime B were to be prescribed approximately 20% less fluid over the first week. Daily fluid input and output were recorded. Serum electrolytes, bilirubin, creatinine and urine osmolalities were measured daily. Arginine vasopressin levels were assessed on days 1, 3 and 5. Episodes of jaundice, hypoglycaemia and hypotension requiring treatment were noted. Infants on regime B actually received overall 11% and, in the first 4 days, 19% less fluid than those on regime A (p < 0.001). There were no statistically significant differences in the occurrence of episodes of jaundice, hypotension, hypoglycaemia, hypernatraemia or hyponatraemia between infants on the two regimes. Although the infants on regime B had significantly higher urine osmolalities and lower urine output for most of the perinatal period, their median creatinine and arginine vasopressin levels did not differ significantly from those on regime A. We conclude that fluid restriction to less than 90% of usual maintenance fluids is not associated with an excess of acute adverse effects.

Computer assisted analysis of the chest radiograph lung area and prediction of failure of extubation from mechanical ventilation in preterm neonates

Post-extubation chest radiographs (CXRs) are frequently requested on the neonatal intensive care unit, but it is controversial whether they generate useful information. A low lung volume assessed by measurement of functional residual capacity (FRC) post extubation has been demonstrated to predict extubation failure, which is a subsequent requirement for increased respiratory support. We have previously shown that the CXR lung area obtained by computer assisted analysis significantly correlated with FRC and, therefore, speculated that a low CXR lung area post extubation would reliably predict extubation failure. The aim of this study was to test the hypothesis by analysing CXRs from 20 infants, with median gestational age of 28 weeks (range 25-33 weeks) and postnatal age 4 days (range 1-11 days). CXRs were obtained within 4 h of extubation and were scanned and analysed using a Power Macintosh computer with a Wacom A5 Ultra pad and NIH image software. The cardiac, mediastinal and thymic shadows, and areas of perihilar and lobar consolidation were subtracted from the thoracic area to give the lung area. Seven infants failed extubation and differed significantly from the rest of the cohort only with regard to their CXR lung area, median gestational age, birth weight and postnatal age. Receiver operator characteristic (ROC) curves were constructed and the areas under each ROC curve were compared. Analysis demonstrated that a low CXR lung area and an older postnatal age were the best predictors of extubation failure. A post-extubation CXR lung area of < 8.5 cm2 had the highest specificity (100%) in predicting extubation failure. We conclude that routine post-extubation CXRs can have a useful role.

Maximal airway pressures during crying in healthy preterm and term neonates

Respiratory muscle strength can be assessed by measurement of maximal inspiratory (PIMAX) and maximal expiratory pressure (P(EMAX)) during crying. There are, however, relatively few data on P(IMAX) and P(EMAX) in infancy, particularly from those born preterm. Our aim was to investigate which factors influenced P(IMAX) and P(EMAX) in preterm and term infants. Forty infants, median gestational age 37 weeks (range 26-43) and birthweight 2.579 kg (range 0.956-5.180) were studied at a postconceptional age (PCA) of 38 weeks (range 32-44). None had respiratory problems. A facemask was placed firmly over the infant's mouth and nose and the infant studied during spontaneous crying. A pneumotachograph fitted snugly into the facemask and from a sideport airway pressure changes were measured. During crying, the distal end of the pneumotachograph was occluded for five breaths and at least three separate occlusions were made. The highest P(EMAX) value sustained for at least 1 s and the highest peak inspiratory pressure P(IMAX) were recorded. The mean P(IMAX) and P(EMAX) were higher in the term compared to the preterm infants (70 cmH2O +/-S.D. 19 versus 58 cmH2O +/-S.D. 17 P(IMAX) and 53 cmH2O +/-S.D. 13 versus 44 cmH2O +/-S.D. 19 P(EMAX), P< 0.05). Both P(IMAX) and P(EMAX) related significantly with postconceptional age, gestational age and weight, but not postnatal age. Stepwise regression analysis demonstrated P(IMAX) related independently with PCA and P(EMAX) with weight. These results suggest respiratory muscle strength is influenced by maturation at birth.

Neonatal lung function in very immature infants with and without RDS

Some infants, despite being born at low gestations (< 28 weeks gestational age) do not develop RDS and are not surfactant treated. The changes in lung function during the neonatal period in such infants have not been explored, hence it is unknown whether they are similar to those of surfactant treated infants with RDS of similar gestational age. Such data would facilitate assessment of the impact of surfactant administration on the lung function abnormalities of very immature infants with RDS. We, therefore, compared the results of neonatal lung function measurements from immature infants with RDS who received surfactant to those from infants with non-RDS respiratory distress not so treated and matched to the RDS infants for gestational age and within 10% of birthweight. Compliance and functional residual capacity (FRC) were measured daily for the first five days and then at 1, 2 and 4 weeks in 16 infants, median gestational age 27 weeks (range 25-27 weeks). Although exogenous surfactant administration to the immature infants with RDS was associated with improvements in lung function, the non RDS, non surfactant treated infants had both higher compliance (p < 0.05) and lung volumes (p < 0.01) throughout the perinatal period. These results demonstrate surfactant administration does not fully correct the perinatal lung function abnormalities of very immature infants with RDS.

Morbidity in infants with antenatally-diagnosed anterior abdominal wall defects

The aims of this study were to compare the morbidity of infants with gastroschisis (GS) with that of infants with exomphalos (EX) without lethal abnormalities and to identify factors predictive of adverse outcome: a requirement for parenteral nutrition (PN) for over 1 month and hospital admission for over 2 months. The medical records of 45 infants with anterior wall defects (32 with GS) diagnosed antenatally who consecutively received intensive care in one institution from 1993 were reviewed. Both the GS and EX infants had a median gestational age of 37 weeks, but the former were lighter at birth (P < 0.01). Fourteen infants (all with GS) were able to start feeds only after 2 weeks; 10 (8 with GS) developed liver dysfunction; and 5 (all with GS) died. The GS compared to the EX infants required a longer period of PN (median 20 vs 10 days, P < 0.01) and longer hospital admission (median 40 vs 25 days, P < 0.01). In the GS group the time to start feeding related independently to prolonged hospital stay, and the existence of structural bowel abnormalities (SBA) related independently to both measures of adverse outcome, with a positive predictive value of 100%. We conclude that infants with GS, particularly those with SBA, suffer greater morbidity than infants with EX without lethal abnormalities.

Synchronized mechanical ventilation for respiratory support in newborn infants

BACKGROUND

During synchronous ventilation, positive pressure ventilation and spontaneous inspiration coincide. Thus, if synchronous ventilation is provoked, it is likely that adequate gas exchange should be achieved at lower peak pressures, reducing barotrauma and hence airleak and chronic lung disease. Synchronous ventilation can be achieved by manipulation of rate and inspiratory time during conventional ventilation and employment of patient assisted ventilation.

OBJECTIVES

To compare (i) the efficacy of synchronized mechanical ventilation, delivered as high frequency positive pressure ventilation or triggered ventilation (patient triggered ventilation (PTV) or synchronous intermittent mandatory ventilation (SIMV)) with conventional ventilation (ii) different types of triggered ventilation

SEARCH STRATEGY

Searches were made of the Oxford Database of Perinatal Trials, Medline (MESH terms: mechanical ventilation; triggered ventilation; newborn infant); previous reviews, abstracts, symposia proceedings, hand searching of journals in the English language and contacting expert informants.

SELECTION CRITERIA

Randomized or quasi randomized clinical trials comparing synchronized ventilation delivered as high frequency positive pressure ventilation (HFPPV) or triggered ventilation (PTV/SIMV) to conventional ventilation (CMV) in neonates. Randomized trials comparing different triggered ventilation modes (PTV and SIMV) in neonates.

DATA COLLECTION AND ANALYSIS

Data regarding clinical outcomes including mortality, airleaks (pneumothorax or pulmonary interstitial emphysema (PIE)), severe intracerebral haemorrhage (grades 3 and 4), chronic lung disease (oxygen dependency beyond 28 days) and duration of weaning/ventilation. Data subdivided into three groups: (i) HFPPV vs CMV; (ii) PTV/SIMV vs CMV; (iii) PTV vs SIMV. Data analysis was conducted according to the standards of the Neonatal Cochrane Review Group.

MAIN RESULTS

The meta-analysis demonstrates that HFPPV compared to CMV was associated with a reduction in the risk of airleak (typical relative risk 0.68, 95% CI 0.55, 0.68). PTV/SIMV compared to CMV was associated with a shorter duration of ventilation (Weighted mean difference -45.2 hours, 95% CI -78.3, -12.1). PTV compared to SIMV was associated with a trend to a shorter duration of weaning (Weighted mean difference 42.4 hours, 95% CI -9.6,94.4). No disadvantage to HFPPV or triggered ventilation was noted regarding other outcomes.

REVIEWER'S CONCLUSIONS

Compared to conventional ventilation, benefit is demonstrated for both HFPPV and triggered ventilation with regard to a reduction in airleak and a shorter duration of ventilation respectively. In none of the trials was complex respiratory monitoring undertaken and thus it is not possible to conclude that the mechanism of producing those benefits is by provocation of synchronized ventilation. Further trials are needed to determine whether synchronized ventilation is associated with a reduction in chronic oxygen dependency.

Early prediction of chronic oxygen dependency by lung function test results

Chronic oxygen dependency (COD) is a common sequela to very premature birth. Steroid therapy may reduce COD if given within the first 2 weeks, but has important side effects. It is, therefore, crucial to identify an accurate predictor of COD and hence only expose high-risk infants to intervention therapy. The aim of this study was to determine if, within 48 hr of birth, abnormal lung function predicted COD and whether such results performed better than readily available clinical data. Results from 100 consecutive, very low birth-weight infants, median gestation age 28 weeks (range, 24-33), who were ventilated within 6 hr of birth and survived beyond 36 weeks postconceptional age (PCA), were analyzed. Lung volume was assessed by measurement of functional residual capacity (FRC) using a helium gas dilution technique, and compliance was measured using either a passive inflation or an occlusion technique. The maximum peak inflating pressure and inspired oxygen concentration within the first 48 hr were recorded. The infants who remained oxygen-dependent beyond 28 days (n = 58) and 36 weeks PCA (n = 24) differed from the rest in being more immature (P < 0.001), more had a patent ductus arteriosus, and they had both a lower median lung volume (P < 0.001) and lower compliance (P < 0.01) on day 2. An FRC <19 mL/kg and a low gestational age were the most accurate predictors of COD at 28 days. An FRC <19 mL/kg on day 2 remained the best predictor of COD beyond 28 days if only the 50 infants whose gestational age was < or = 28 weeks were considered. We conclude that demonstration of a low lung volume in the first 48 hr helps to identify infants who might benefit from therapy aimed at preventing COD.

Plasma arginine levels and the response to inhaled nitric oxide in neonates

Inhaled nitric oxide (iNO) can be an effective vasodilator in pulmonary hypertension of the newborn (PHN). The aim of this study was to determine whether differences in arginine levels, from which endogenous NO is produced, explain the variability in response to NO and whether the arginine levels were lower in term and preterm infants with PHN than in infants without PHN (controls). We prospectively studied 30 infants (17 born preterm) with clinically diagnosed PHN and treated with iNO and 22 controls (14 born preterm). Three NO levels (10, 20, 40 ppm) were administered to the PHN infants to identify that associated with maximum oxygenation. Twenty-seven infants with PHN improved following iNO and had lower arginine levels than those infants who did not respond to iNO (p < 0. 05). No significant relationship, however, was noted between the arginine levels and either the magnitude of change in the oxygenation index in response to iNO or the NO level associated with maximum oxygenation. The median plasma arginine level prior to iNO of the PHN infants was 12.5 (range 2-53) mu mol/l, but not significantly lower than that of the controls (median 24, range 3-82 mu mol/l). We conclude that differences in plasma arginine levels are unlikely to explain the variation in response to iNO and that, although arginine levels tended to be lower in infants with PHN, this is not a consistent finding in either the term or preterm infants.

Comparison of the effect of two fluid input regimens on perinatal lung function in ventilated infants of very low birthweight

Fluid overload worsens respiratory failure; conversely, fluid restriction has been associated with a higher survival rate without chronic lung disease. We therefore hypothesised that fluid restriction in the perinatal period might improve lung function in ventilated, prematurely born infants of very low birthweight. As a consequence, we compared in a randomised trial the effect of two fluid regimes on perinatal lung function. On one regime infants were to receive 60 ml/kg on day 1, increasing to 150 ml/kg by day 7, and on the other regime approximately 25% less fluid was to be prescribed. Lung function was assessed by measurement of functional residual capacity (FRC) and compliance. Measurements were made daily on days 1 to 5 and then on day 7. Ninety infants, median gestational age 28 weeks (range 23-33), were included in the study. There were no significant differences between the two groups regarding their gestational age or birthweight, or in the proportions who received antenatal steroids or postnatal surfactant. The infants on the restricted regime received significantly less fluid (P < 0.01). The only significant differences in lung function between the two groups, however, were that the infants on the restricted regime had a higher mean compliance on day 3, but thereafter the difference was reversed. Colloid intake, however, unfavourably affected lung function, total colloid intake being negatively correlated with both the area under the curve of birth-adjusted FRC (P=0.003) and compliance (P=0.001).

CONCLUSION

We conclude that early fluid restriction appears to have very little impact on perinatal lung function.

Appropriate positive end expiratory pressure level in surfactant-treated preterm infants

Positive end expiratory pressure (PEEP) is routinely used when ventilating preterm infants, and high levels are recommended in those with severe respiratory distress syndrome (RDS). Elevation of PEEP increases lung volume, as does surfactant administration. We postulated that in surfactant-treated infants even modest PEEP levels could result in overdistension and (CO(2)) retention. To test that hypothesis, lung volume, compliance and arterial blood gases were measured in eight preterm infants (median gestational age 28 weeks, range 26-35 weeks) at three PEEP levels. The infants, all with RDS, were studied at a median time of 18 h, (range 12-68 h) after their last dose of surfactant. Infants were routinely nursed at 3 cmH(2)O of PEEP, the PEEP level was then raised to 6 cmH(2)O or lowered to 0 cmH(2)O in random order. The new setting was maintained for 20 min; the PEEP level was then changed to the third level (0 or 6 cmH(2)O) again for 20 min. At the end of each 20-min period, lung volume, compliance and blood gases were measured. Lung volume was assessed by measuring functional residual capacity (FRC) using a helium dilution technique. Compliance was measured by relating the volume change from a positive pressure inflation maintained until no further volume change occurred to the pressure drop (peak inflating pressure PEEP). Increasing PEEP from 0 to 3 cmH(2)O and particularly to 6 cmH(2)O resulted in increases in FRC (P < 0.05), oxygenation (ns) and paCO(2) (P < 0.02). Specific compliance (compliance/FRC) (P < 0.05) and pH (P < 0.02) fell.

CONCLUSION

Following surfactant treatment, relatively low levels of positive end expiratory pressure (</=3 cmH(2)O) may be appropriate.

Neonatal outcome following early onset preterm premature rupture of the membranes--a case controlled study

A case-controlled study was performed to determine whether preterm premature rupture of the membranes (PPROM), particularly if occurring in the second trimester, increased the duration of ventilatory support or hospital admission. Infants born after membrane rupture of at least 24 hours duration and prior to 37 weeks of gestation were identified. It was possible to match for gestational age and birthweight 40 PPROM infants, 15 of whom had onset of rupture of the membranes (ROM) prior to 27 weeks of gestation, with a control (an infant whose mother had not suffered PPROM). A greater proportion of the mothers of the PPROM infants had received antenatal steroids (p<0.01), had an antepartum hemorrhage (p=0.06) or delivered vaginally (p<0.02). More PPROM infants had pulmonary hypoplasia (p<0.03) or infection (p<0.01). Overall, however, and if only those matched pairs where membrane rupture had occurred prior to 27 weeks of gestation were considered, there were no statistically significant differences in the duration of ventilatory support or hospital admission. Step-wise regression analysis confirmed that in the study population overall and in the matched pairs where membrane rupture had occurred at less than 27 weeks of gestation, neither the duration of ventilation nor hospital admission significantly related to PPROM. These findings have implications when counselling parents.

Comparison of two inspiratory: expiratory ratios during high frequency oscillation

The aim of this study was to compare gas exchange and volume delivery during high frequency oscillation at two frequently used inspiratory:expiratory (I:E) ratios: 1:2 and 1:1, other oscillatory settings being kept constant. A group of 13 infants with respiratory distress syndrome, median gestational age 28 weeks (range 23-36) and postnatal age 1 day (range 1-8) were studied. At the I:E ratio of 1:1 compared to 1:2 the median paCO(2) was lower, P < 0.05 (30 mmHg, range 22-47 vs 34 mmHg, range 27-46) and the volume delivered higher, P < 0.01 (2.6 ml/kg, range 1.2-5.6 vs 2.0 ml/kg, range 1.0-3.9). There was no significant difference in oxygenation levels at the two I:E ratios. In a related in vitro study, changing the I:E ratio from 1:2 to 1:1 increased the mean airway pressure by a median of 8.6% (range 2.9-28.1%).

CONCLUSION

Routinely maintained longer expiratory than inspiratory times during high frequency oscillation should be discouraged.

Blood pressure rhythms during the perinatal period in very immature, extremely low birthweight neonates

The aim of this study was to investigate if blood pressure (BP) rhythms were present in the perinatal period in very immature infants. Twenty-two infants, median gestational age 24-28 weeks, who had indwelling arterial lines with undamped arterial BP waveforms, were studied. The infants were all receiving intensive care under constant conditions. The hourly mean, systolic and diastolic BPs on days 2 and 7 were examined. A cosinor analysis of the mean BP was performed examining period lengths of 4, 8, 12, 16, 20, and 24 h to determine whether ultradian and/or circadian rhythms existed. On day 2, but not day 7, the mean and systolic BPs showed significant variation and circadian and ultradian rhythms were demonstrated. We suggest that maternal influences may be responsible for the BP rhythms noted in very immature infants on day 2.