Cardiopulmonary Exercise Performance of Children Born Non-Extremely Preterm.

Data on exercise tolerance of children born non-extremely preterm are sparse. We aimed to explore the cardiopulmonary exercise testing (CPET) characteristics in this population. We studied 63 children (age 7-12 years) born at 290/7-366/7 weeks of gestation (34 were late preterm, 29 were preterm) and 63 age-matched, term-born controls. All performed spirometry and CPET (cycle ergometry). There were no differences in activity levels and spirometric parameters between the group of preterm-born children and controls. A peak oxygen uptake (VO2peak) of <80% was noted in 25.4% of the term-born and 49.2% of preterm-born children (p = 0.001). Term-born participants presented similar VO2peak to late-preterm children but higher than those born at <340/7 weeks of gestation (p = 0.002). Ventilatory limitation was noted in 4.8% of term and 7.9% of preterm participants, while only one preterm child presented cardiovascular limitation. Children born before 34 weeks of gestation had higher respiratory rates and smaller tidal volumes at maximum exercise, as well as lower oxygen uptake for the level of generated work. We conclude that school-age children born at 29-34 weeks of gestation may present decreased exercise performance attributed to an altered ventilatory response to exercise and impaired O2 utilization by their skeletal muscles rather than other cardiopulmonary limiting factors.

Flow-resistive loading and diaphragmatic muscle function in term and preterm infants.

PURPOSE: We aimed to assess diaphragmatic function in term and preterm infants with and without history of bronchopulmonary dysplasia (BPD), before and after the application of inspiratory flow resistive loading. METHODS: Forty infants of a median (range) gestational age of 34 (25-40) weeks were studied. BPD was defined as supplemental oxygen requirement for >28 days of life. Seventeen infants were term, 17 preterm without history of BPD, and six preterm with a history of BPD. The diaphragmatic pressure-time index (PTIdi) was calculated as the mean to maximum trans-diaphragmatic pressure ratio times the inspiratory duty cycle. The PTIdi was calculated before and after the application of an inspiratory-flow resistance for 120 s. Airflow was measured by a pneumotachograph and the transdiaphragmatic pressure by a dual pressure catheter. RESULTS: The median (interquartile range [IQR]) pre-resistance PTIdi was higher in preterm infants without BPD (0.064 [0.050-0.077]) compared with term infants (0.052 [0.044-0.062], p = .029) and was higher in preterm infants with BPD (0.119 [0.086-0.132]) compared with a subgroup of preterm infants without BPD (0.062 [0.056-0.072], p = .004). The median (IQR) postresistance PTIdi was higher in preterm infants without BPD (0.101 [0.084-0.132]) compared with term infants (0.067 [0.055-0.083], p < .001) and was higher in preterm infants with BPD [0.201(0.172-0.272)] compared with the preterm subgroup without BPD (0.091 [0.081-0.108],p = .004). The median (IQR) percentage change of the PTIdi after the application of the resistance was higher in preterm infants without BPD (65 [51-92] %) compared with term infants (34 [20-39] %, p < .001). CONCLUSIONS: Preterm infants, especially those recovering from BPD, are at increased risk of diaphragmatic muscle fatigue under conditions of increased inspiratory loading.

Diaphragmatic muscle function in term and preterm infants.

We aimed to assess the determinants of diaphragmatic function in term and preterm infants. 149 infants (56 term; 93 preterm, of whom 14 were diagnosed with bronchopulmonary dysplasia-BPD) were studied before discharge. Diaphragmatic function was assessed by measurement of the maximum transdiaphragmatic pressure (Pdimax)-a measure of diaphragmatic strength, and the pressure-time index of the diaphragm (PTIdi)-a measure of the load-to-capacity ratio of the diaphragm. The Pdimax was higher in term than preterm infants without BPD (90.1 ± 16.3 vs 81.1 ± 11.8 cmH2O; P = 0.001). Term-born infants also had lower PTIdi compared to preterms without BPD (0.052 ± 0.014 vs 0.060 ± 0.017; P = 0.006). In term and preterm infants without BPD, GA was the most significant predictor of Pdimax and PTIdi, independently of the duration of mechanical ventilation and oxygen support. In infants with GA < 32 weeks (n = 30), the Pdimax was higher in infants without BPD compared to those with BPD (76.1 ± 11.1 vs 65.2 ± 11.9 cmH2O; P = 0.015). Preterms without BPD also had lower PTIdi compared to those with BPD (0.069 ± 0.016 vs 0.109 ± 0.017; P < 0.001). In this subgroup, GA was the only significant independent determinant of Pdimax, while BPD and the GA were significant determinants of the PTIdi.  Conclusions: Preterm infants present lower diaphragmatic strength and impaired ability to sustain the generated force over time, which renders them prone to diaphragmatic fatigue. In very preterm infants, BPD may further aggravate diaphragmatic function. What is Known: • The diaphragm of preterm infants has limited capacity to undertake the work of breathing effectively. • The maximum transdiaphragmatic pressure (a measure of diaphragmatic strength) and the pressure-time index of the diaphragm (a measure of the load-to-capacity ratio of the muscle) have not been extensively assessed in small infants. What is New: • Preterm infants have lower diaphragmatic strength and impaired ability to sustain the generated force over time, which renders them prone to diaphragmatic fatigue. • In very preterm infants, bronchopulmonary dysplasia may further impair diaphragmatic function.

Post-Traumatic Stress as a Psychological Effect of Mild Head Injuries in Children.

BACKGROUND: Head trauma is one of the most common pediatric emergencies. While the psychological effects of severe head injuries are well studied, the psychological consequences of mild head injuries often go overlooked. Head injuries with a Glasgow Coma Scale score of 13-15, with symptoms such as headache, vomiting, brief loss of consciousness, transient amnesia, and absence of focal neurological signs, are defined as mild. The aim of this study is to evaluate the stress of children with mild head injuries and their parents' relevant perception during the early post-traumatic period. METHODS: This is a prospective cross-sectional study on a cohort of children with mild head injuries and their parents. Two questionnaires were implemented, the Child Trauma Screening Questionnaire (CTSQ) which was compiled by the children, and the Children's Revised Impact of Event Scale (CRIES-13), compiled by their parents. Both questionnaires are widely used and reliable. The first presents an excellent predictive ability in children with a risk of post-traumatic stress disorder, while the second is a weighted self-completed detecting instrument for the measurement of post-traumatic stress in children and adolescents, with a detailed evaluation of their reactions to the traumatic incident. The participants responded one week and one month after the traumatic event. RESULTS: A total of 175 children aged 6-14 years and 174 parents participated in the study. Stress was diagnosed in 33.7% of children after one week, and in 9.9% after one month. Parental responses suggesting stress presence in their children were 19.0% and 3.9%, respectively. These outcomes showed that mild head injuries are not so innocent. They are often underestimated by their parents and may generate a psychological burden to the children during the early post-traumatic period. CONCLUSIONS: Mild head injuries may affect the emotional welfare of children. Healthcare providers should understand the importance of the psychological effect of this overlooked type of injury. They should be trained in the psychological effect of trauma and be aware of this probability, promptly notify the parents accordingly, and provide psychological assistance beyond medical treatment. Follow-up and support are needed to avoid the possibility of future post-traumatic stress disorder. More extensive research is needed as the outcomes of this study regarded a limited population in numbers, age, and survey period. Furthermore, many children with mild head injuries do not ever visit the emergency department and stay at home unrecorded. Community-based research on the topic should therefore be considered.

Association of the Bacteria of the Vermiform Appendix and the Peritoneal Cavity with Complicated Acute Appendicitis in Children.

BACKGROUND: Primary infection has been questioned as the pathogenetic cause of acute appendicitis. We attempted to identify the bacteria involved and to investigate if their species, types, or combinations affected the severity of acute appendicitis in children. METHODS: Samples from both the appendiceal lumen and the peritoneal cavity of 72 children who underwent appendectomy were collected to perform bacterial culture analysis. The outcomes were studied to identify if and how they were associated with the severity of the disease. Regression analysis was performed to identify any risk factors associated with complicated appendicitis. RESULTS: Escherichia coli, Pseudomonas aeruginosa, and Streptococcus species were the most common pathogens found in the study population. The same microorganisms, either combined or separate, were the most common in the appendiceal lumen and the peritoneal cavity of patients with complicated appendicitis. Gram-negative bacteria and polymicrobial cultures in the peritoneal fluid and in the appendiceal lumen were associated with complicated appendicitis. Polymicrobial cultures in the peritoneal cavity presented a four times higher risk of complicated appendicitis. CONCLUSIONS: Polymicrobial presentation and Gram-negative bacteria are associated with complicated appendicitis. Antibiotic regimens should target the combinations of the most frequently identified pathogens, speculating the value of early antipseudomonal intervention.

Early Diagnosis of Late-Onset Neonatal Sepsis Using a Sepsis Prediction Score.

Sepsis represents a common cause of morbidity in the Neonatal Intensive Care Unit (NICU). Our objective was to assess the value of clinical and laboratory parameters in predicting septicemia (positive blood culture) in NICU infants. In the first part of the present study (derivation cohort) we retrospectively reviewed the clinical files of 120 neonates with symptoms of suspected sepsis and identified clinical and laboratory parameters associated with proven sepsis on the day the blood culture was taken, as well as 24 h and 48 h earlier. These parameters were combined into a sepsis prediction score (SPS). Subsequently (validation study), we prospectively validated the performance of the SPS in a cohort of 145 neonates. The identified parameters were: temperature instability, platelet count < 150,000/mm3, feeding volume decrease > 20%, changes in blood glucose > 50%, CRP > 1 mg/dL, circulatory and respiratory deterioration. In the retrospective cohort, on the day the blood culture was obtained, a SPS ≥ 3 could predict sepsis with 82.54% sensitivity, 85.96% specificity, 5.88 PLR (Positive Likelihood Ratio), 0.20 NLR (Negative Likelihood Ratio), 86.67% PPV (Positive Predictive Value), 81.67% NPV (Negative Predictive Value) and 84.17% accuracy. In the prospective cohort, on the day the blood culture was obtained, a SPS ≥ 3 could predict sepsis with 76.60% sensitivity, 72.55% specificity, 2.79 PLR, 0.32 NLR, 83.72% PPV, 62.71% NPV and 75.17% accuracy. We concluded that this combination of clinical and laboratory parameters may assist in the prediction of septicemia in NICUs.

Clinical outcome in newborns of perinatally COVID-19 infected women.

OBJECTIVE: Maternal COVID-19 infection during pregnancy has been associated with adverse neonatal outcomes, such as prematurity and neonatal morbidity. Those adverse events are mainly attributed to maternal factors, rather than to the neonatal infection itself. Our aim is to add our experience and present the neonatal outcome of neonates born to mothers with perinatal SARS-CoV-2 infection. METHODS: This is a prospective case-control study with data from two Academic Tertiary Referral Hospitals in Greece. Electronic records of all births from SARS-CoV-2 positive mothers between March 2020 and April 2021 were analyzed. Demographic data, the severity of maternal COVID-19 disease, gestational age (GA), mode of delivery, birth weight (BW), need for resuscitation and/or supplemental oxygen and duration of hospitalization were recorded. A comparison with 2:1 matched neonates according to sex, GA, and BW born to SARS-CoV-2 negative mothers during the same period was performed. Chi-square and Mann-Whitney U test were used for categorical and non-categorical variables respectively. RESULTS: A total of eighty-one neonates were born to SARS-CoV-2 positive mothers during this period. Forty-three percent of pregnant mothers were asymptomatic. Median GA and median BW were 38 weeks (Interquantile range (IQR): 36-39 weeks) and 2940 gr (IQR: 2560-3340 gr) respectively. Prematurity was observed in 24.7% of the cases. Only 2 (2.4%) neonates were PCR positive after delivery. SARS-CoV-2 positive women were more likely to undergo Cesarean section. APGAR score at 5 min and the need for resuscitation did not differ between the two groups. In comparison with the control group, neonates born to SARS-CoV-2 positive mothers presented with gastrointestinal symptoms (53.6% vs 5.1%, p-value= <.001) and hospitalization was longer, mostly due to maternal factors. CONCLUSION: In our study neonatal positivity was limited and no vertical transmission was noted. Neonatal outcomes were comparable to the control group. However, the presence of gastrointestinal symptoms in neonates born to PCR-positive women compared to controls needs further investigation.

Validation of a non-invasive pressure-time index of the inspiratory muscles in spontaneously breathing newborn infants.

To validate the pressure-time index of the inspiratory muscles as a non-invasive index of inspiratory muscle function in spontaneously breathing infants by comparing it against the gold-standard pressure-time index of the diaphragm. Prospective observational cohort study of consecutive infants breathing unsupported in room air in a tertiary neonatal intensive care unit, studied prior to discharge from neonatal care. The invasive pressure-time index of the diaphragm was calculated using a transdiaphragmatic dual-pressure catheter that measured transdiaphragmatic pressure by subtraction of the oesophageal from the gastric pressure. The non-invasive pressure-time index of the inspiratory muscles was calculated using pressure measurements at the level of the mouth via a differential pressure transducer connected to a face mask. Both indices were calculated as the product of the ratio of the mean inspiratory pressure divided by the maximum inspiratory pressure and the ratio of the inspiratory time divided by the total time of a respiratory cycle. One hundred and thirty infants (79 male) were included with a mean (SD) gestational age of 35.2 (3.2) weeks, studied at a median (IQR) postnatal age of 9 (6-20) days. The mean (SD) pressure-time index of the diaphragm was 0.063 (0.019) and the mean (SD) pressure-time index of the inspiratory muscles was 0.065 (0.023). The correlation coefficient for the two indices was 0.509 (p < 0.001). The mean (SD) absolute difference between the pressure-time index of the inspiratory muscles and pressure-time index of the diaphragm was 0.002 (0.021). In convalescent infants, the non-invasive pressure-time index of the inspiratory muscles had a moderate degree of correlation with the invasively derived pressure time index of the diaphragm measured with a transdiaphragmatic catheter.

Parental and Pediatricians' Attitudes towards COVID-19 Vaccination for Children: Results from Nationwide Samples in Greece.

Although many studies have examined factors associated with COVID-19 vaccination and healthcare professionals' attitudes towards vaccines, less is known about parents' and pediatricians' attitudes towards COVID-19 vaccination for children. Using two cross-sectional surveys from November to December 2021 in Greece, we aimed to assess parental intention to vaccinate their 5 to 17 years old children against COVID-19 and to evaluate pediatricians' attitudes towards children's vaccination against COVID-19. Overall, 439 parents and 135 pediatricians participated. Of them, 240 (54.7%) intended to vaccinate their children against COVID-19. The most commonly reported reasons for non-intention were the short length of clinical trials and the fear of side effects. Only 16.6% of non-intenders would vaccinate their children if the pediatrician recommended it. The factors associated with higher intention to get vaccinated were a parent's own vaccination against COVID-19, trust in official healthcare guidelines, increased trust in the state and the healthcare system during the pandemic, and older age. Of the pediatricians, 92.6% recommended children's vaccination, and 75.6% agreed with mandating the vaccine. These findings suggest the need to tailor easy-to-understand messages by well-informed pediatricians to address safety concerns, educate, and clarify misconceptions through targeted interventions among those who currently do not wish to vaccinate their children.

Hearing Outcomes of Infants Born to Mothers With Active COVID-19 Infection.

Introduction COVID-19, caused by SARS-CoV-2, is a highly contagious respiratory tract infection. A major concern of SARS-CoV-2 infection in pregnant women is vertical maternal-fetal transmission and the ramifications on infant hearing. This retrospective study aims to investigate whether perinatal exposure to SARS-CoV-2 has an impact on the hearing of the offspring. Materials The study population included neonates born to unvaccinated COVID-19 positive mothers in the University Hospital of Patras, Greece from March 2020 to January 2021. Polymerase chain reaction (PCR) tests were performed on the neonates on the first, second,, and seventh day of life. All neonates underwent transient evoked otoacoustic emissions (TEOAEs) within the first three months of life and were all examined at the age of nine months. Results Thirty-two neonates (21 male) were born within the study period and all were transferred to the Neonatal Intensive Care Unit (NICU). Their mean (SD) gestational age was 36.9 (+2.23) weeks and their birth weight was 2,943 (+537) g. Nine of them were preterm and six of them had a low birth weight. Apgar scores calculated at 1' and 5', were in the normal range for 31 (97%) out of 32 neonates. One infant required urgent intubation at birth with an Apgar score of 1' 3 and 5' 4. Four neonates required mechanical ventilatory support, two neonates required nasal CPAP and eight neonates required supplementary oxygen. All infants were negative for TORCH infections. PCR tests were performed within the first day of life and repeated at 48 hours and on the seventh day of life. All PCR tests came back negative. Out of 32 neonates, seven failed the TEOAE test and were tested again a month later with a positive outcome. At nine months of follow-up, all 32 infants passed the TEOAE test. Conclusion In conclusion, in our study, there was no evidence of vertical transmission of SARS-CoV-2 from mothers infected during the third trimester or hearing impairment of the offspring.

Predictive Scores for Late-Onset Neonatal Sepsis as an Early Diagnostic and Antimicrobial Stewardship Tool: What Have We Done So Far?

BACKGROUND: Late-onset neonatal sepsis (LOS) represents a significant cause of morbidity and mortality worldwide, and early diagnosis remains a challenge. Various 'sepsis scores' have been developed to improve early identification. The aim of the current review is to summarize the current knowledge on the utility of predictive scores in LOS as a tool for early sepsis recognition, as well as an antimicrobial stewardship tool. METHODS: The following research question was developed: Can we diagnose LOS with accuracy in neonates using a predictive score? A systematic search was performed in the PubMed database from 1982 (first predictive score published) to December 2021. RESULTS: Some (1352) articles were identified-out of which, 16 were included in the review. Eight were original scores, five were validations of already existing scores and two were mixed. Predictive models were developed by combining a variety of clinical, laboratory and other variables. The majority were found to assist in early diagnosis, but almost all had a limited diagnostic accuracy. CONCLUSIONS: There is an increasing need worldwide for a simple and accurate score to promptly predict LOS. Combinations of the selected parameters may be helpful, but until now, a single score has not been proven to be comprehensive.

Persistent Coagulase-Negative Staphylococcal Bacteremia in Neonates: Clinical, Microbiological Characteristics and Changes within a Decade.

Atypical outbreaks of persistent coagulase-negative staphylococci (CoNS) bacteremias, defined as three or more consecutive positive blood cultures with the same CoNS species, at least 48 h apart, have been reported in neonatal intensive-care units (NICUs). Our aim was to describe the profile of these cases in our NICU over a two-year period with the objective of assessing possible changes within a decade. Demographics, clinical and microbiological data were recorded for all CoNS bacteremias in our tertiary NICU during 2016-2017 and compared with the results of the same study in 2006-2007. Fifty-six cases of CoNS sepsis were recorded. Fourteen (25%) of them were persistent. There were no significant differences in demographic and clinical characteristics between cases with persistent vs. non-persistent bacteremia. Staphylococcus epidermidis was the most common species. In logistic regression analysis, biofilm production (ß = 2.464, p = 0.04) was the most significant determinant for the development of persistent CoNS bacteremia. Our isolates were less likely to produce biofilm and carry ica operon as compared to those of 2006-2007. The cases of persistent CoNS sepsis have decreased within a decade, which could be attributed to the implementation of intensive infection control practices. Biofilm production remains the most important risk factor.

Parental attitudes towards vaccination against COVID-19 of children 5-11 years old in Greece.

RATIONALE: Vaccinating children against COVID-19 is critical to contain the ongoing pandemic. AIMS/OBJECTIVES: The aim of the present study was to assess parents' and caregivers' intention to vaccinate their 5-11 years old children against COVID-19 and to estimate the association between vaccination intention and sociodemographic, clinical and contextual factors. METHOD: We conducted a questionnaire-based survey on a convenience sample of parents in Patras, Western Greece. RESULTS: Out of 366 study participants, around 48% reported their intention to vaccinate their child. The main factors associated with positive attitudes were paediatrician recommendation, parental vaccination, and reliance on the healthcare providers for decision making. Of note, 80% of the 190 parents who did not intend to vaccinate their children would vaccinate them if the paediatrician recommended it. CONCLUSION: Interventions to further train healthcare professionals to establish rapport with parents, and to provide adequate information about vaccinations are crucial to address concerns related to COVID-19 vaccine benefits for children.

Respiratory muscle function in the newborn: a narrative review.

Our aim was to summarise the current evidence and methods used to assess respiratory muscle function in the newborn, focusing on current and future potential clinical applications. The respiratory muscles undertake the work of breathing and consist mainly of the diaphragm, which in the newborn is prone to dysfunction due to lower muscle mass, flattened shape and decreased content of fatigue-resistant muscle fibres. Premature infants are prone to diaphragmatic dysfunction due to limited reserves and limited capacity to generate force and avoid fatigue. Methods to assess the respiratory muscles in the newborn include electromyography, maximal respiratory pressures, assessment for thoraco-abdominal asynchrony and composite indices, such as the pressure-time product and the tension time index. Recently, there has been significant interest and a growing body of research in assessing respiratory muscle function using bedside ultrasonography. Neurally adjusted ventilator assist is a novel ventilation mode, where the level of the respiratory support is determined by the diaphragmatic electrical activity. Prolonged mechanical ventilation, hypercapnia and hypoxia, congenital anomalies and systemic or respiratory infection can negatively impact respiratory muscle function in the newborn, while caffeine and synchronised or volume-targeted ventilation have a positive effect on respiratory muscle function compared to conventional, non-triggered or pressure-limited ventilation, respectively. IMPACT: Respiratory muscle function is impaired in prematurely born neonates and infants with congenital anomalies, such as congenital diaphragmatic hernia. Respiratory muscle function is negatively affected by prolonged ventilation and infection and positively affected by caffeine and synchronised compared to non-synchronised ventilation modes. Point-of-care diaphragmatic ultrasound and neurally adjusted ventilator assist are recent diagnostic and therapeutic technological developments with significant clinical applicability.

Parental Knowledge, Attitude, and Practices on Antibiotic Use for Childhood Upper Respiratory Tract Infections during COVID-19 Pandemic in Greece.

This cross-sectional study aims to assess parents' knowledge, attitude, and practices on antibiotic use for children with URTIs symptoms in Greece in the era of the COVID-19 pandemic. We distributed a questionnaire to a random sample of parents who visited primary health care centers in Patras, Greece. Out of 412 participants, 86% believed that most infections with common cold or flu symptoms were caused by viruses, although 26.9% believed that antibiotics may prevent complications. Earache was the most common symptom for which antibiotics were needed. Most of them (69%) declare being considerably anxious about their children's health during the COVID-19 pandemic. The majority (85%) knew that COVID-19 was of viral origin, yet half of them declared uncertain whether antibiotics were needed. All demographic characteristics, except for gender, were found to have a significant effect on parents' knowledge, attitude, and practices on antibiotic use for URTIs and COVID-19. Factor analysis revealed six groups of parents with common characteristics associated with misuse of antibiotics. Our findings highlight the need to decrease misconceptions regarding antibiotic use by providing relevant education for parents targeting particular characteristics, especially during the COVID-19 pandemic. Continuous education of healthcare providers in the field is also of paramount importance.

Changing trends in the prevalence of childhood asthma over 40 years in Greece.

BACKGROUND: A series of repeated questionnaire surveys among 8- to 9-year-old school children in the city of Patras, Greece, demonstrated a continuous rise in the prevalence of wheeze/asthma from 1978 to 2003, with a plateau between 2003 and 2008. We further investigated wheeze/asthma trends within the same environment over the last decade. METHODS: Two follow-up surveys were conducted in 2013 (N = 2554) and 2018 (N = 2648). Physician-diagnosed wheeze and asthma were analyzed in relation to their occurrence (recent-onset: within the last 2 years; noncurrent: before 2 years; persistent: both prior and within the last 2 years). In 2018, spirometry was also performed in participants reporting symptoms and in a sample of healthy controls. RESULTS: The prevalence of current wheeze/asthma declined from 6.9% in 2008% to 5.2% in 2013% and 4.3% in 2018. The persistent and noncurrent wheeze/asthma groups followed this overall trend (P-for-trend <0.001), while the prevalence of recent-onset wheeze/asthma remained unchanged (P-for-trend >0.05). Persistent and noncurrent wheezers were also more frequently diagnosed with asthma, in contrast to those with recent-onset wheeze. The FEV1 z-score was less than -1 in 32.1% of children with recent-onset and in 22.4% of those with persistent wheeze/asthma; both rates were higher than those of the Noncurrent wheeze/asthma group (7.1%; p < .05) and of healthy controls (3.5%; p < .001). CONCLUSIONS: The prevalence of childhood wheeze/asthma has declined significantly during the last decade in Greece. The reversing trend may in part be attributed to changing asthma perceptions among physicians and/or parents, especially in the case of younger children with troublesome respiratory symptoms.

Effect of prone and supine positioning on the diaphragmatic work of breathing in convalescent preterm infants.

OBJECTIVES: To compare the work of breathing in the prone and supine positions in convalescent prematurely born infants. WORKING HYPOTHESIS: The work of breathing would be lower in the prone compared to the supine position. STUDY DESIGN: Prospective observational cohort study. PATIENT-SUBJECT SELECTION: Consecutive preterm infants breathing unsupported in room air with a gestational age of 28-34 weeks in a tertiary neonatal intensive care unit were studied before discharge from neonatal care. METHODOLOGY: The diaphragmatic pressure time product (PTPdi) was used to assess the work of breathing, calculated as the integration of transdiaphragmatic pressure over the inspiratory time. The PTPdi was measured in prone, supine, and supine with 45° head-up tilt (supine-tilt) positions. RESULTS: The mean (SD) PTPdi was lower in the prone (259 [68] cm H2 O*s/min) compared with the supine position (320 [78] cm H2 O*s/min, p= .005). The mean (SD) PTPdi was lower in the supine-tilt position (262 [76] cm H2 O*s/min) compared with the supine position (p = .032). The PTPdi was not different between the prone and supine-tilt positions (p = .600). The difference in PTPdi between prone and supine was not independently associated with gestational age (standardized coefficient = 0.262, adjusted p= .335), birth weight (standardized coefficient = -0.249, adjusted p= .394) or postmenstrual age at study (standardized coefficient = -0.025, adjusted p= .902). CONCLUSIONS: In convalescent preterm neonates, the work of breathing may be lower in the prone and supine-tilt positions, compared with supine.

Does a brief trial of endotracheal CPAP before extubation increase the work of breathing in preterm infants?

A brief period of endotracheal continuous positive airway pressure (ETT-CPAP) can predict extubation outcome but longer periods are associated with increased work of breathing and extubation failure. In ventilated preterm infants, brief ETT-CPAP does not increase the work of breathing and can be used to predict the outcome of extubation.

Work of Breathing in Mechanically Ventilated Preterm Neonates.

OBJECTIVES: To compare the imposed work of breathing by means of pressure-time product of the diaphragm in newborn infants receiving different modes of mechanical ventilation. DESIGN: Prospective observational crossover study. SETTING: Tertiary care neonatal unit. PATIENTS: Forty preterm newborns (gestational age ≤ 37 wk) in the phase of weaning from mechanical ventilation. INTERVENTIONS: Participants were ventilated in assist control, synchronized intermittent mandatory ventilation, and intermittent mandatory ventilation mode, in a crossover manner. The combination synchronized intermittent mandatory ventilation-pressure support (SIMV-PS) at 50% (SIMV-PS50) and 75% (SIMV-PS75) of the difference between peak inflating and positive end-expiratory pressure, was also applied in a subset of infants (n = 11). Each mode was maintained for 30 minutes. Transdiaphragmatic pressure was obtained by digital subtraction of esophageal from gastric pressure (both measured using a dual pressure-tipped catheter), and pressure-time product of the diaphragm was computed by integration of transdiaphragmatic pressure over inspiratory time. MEASUREMENTS AND MAIN RESULTS: The pressure-time product of the diaphragm was 224.2 ± 112.8 in the intermittent mandatory ventilation mode, 165.8 ± 58.8 in the synchronized intermittent mandatory ventilation mode, and 125.5 ± 61.8 cm H2O × s × min in the assist control mode; all values were significantly different to each other (p < 0.0001). The pressure-time product of the diaphragm difference between assist control and intermittent mandatory ventilation, and assist control and synchronized intermittent mandatory ventilation was negatively related to postmenstrual age (regression coefficient, -0.365; p = 0.020 and -0.341; p = 0.031, respectively). In the SIMV-PS subcohort, the pressure-time product of the diaphragm was significantly higher in the intermittent mandatory ventilation mode as compared with assist control (p < 0.0001) or SIMV-PS75 (p = 0.0027), and in the synchronized intermittent mandatory ventilation mode as compared with assist control (p = 0.0301). CONCLUSIONS: In preterm infants, patient-triggered ventilation modalities result in lower work of breathing than intermittent mandatory ventilation, while the assist control mode is also associated with lower pressure-time product of the diaphragm compared with synchronized intermittent mandatory ventilation. The difference in the imposed diaphragmatic workload between these ventilation modalities was inversely related to postmenstrual age, implying that less mature infants benefit more from assist control-based ventilation strategies.

Prediction of extubation outcome in preterm infants by composite extubation indices.

OBJECTIVE: To determine whether composite extubation indices can predict extubation outcome in preterm infants. DESIGN: Prospective observational study. SETTING: Level III neonatal intensive care unit. PATIENTS: Fifty-six preterm infants cared for in the neonatal intensive care unit of a tertiary teaching hospital during 2007 and 2008. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: The study consisted of two parts. In the first part, different extubation indices were evaluated in a group of 28 neonates (derivation group). These indices included the diaphragmatic pressure-time index, the respiratory muscle pressure-time index, the maximal transdiaphragmatic pressure, the maximal inspiratory pressure, the airway pressure generated 100 milliseconds after an occlusion/maximal transdiaphragmatic pressure ratio, the airway pressure generated 100 milliseconds after an occlusion/maximal inspiratory pressure ratio, the tidal volume, and the respiratory rate to tidal volume ratio. After exploratory analysis, the best performing indices and the optimal threshold values to predict extubation outcome were selected. In the second part of the study, these indices were validated at the predetermined threshold values in an additional group of 28 preterm neonates (validation group). Four infants (14.3%) in the derivation group and four in the validation group (14.3%) failed extubation. Receiver operator characteristic curve analysis revealed that a diaphragmatic pressure-time index of ≤0.12, a respiratory muscle pressure-time index ≤0.10, a airway pressure generated 100 milliseconds after an occlusion/maximal transdiaphragmatic pressure of ≤0.14, and a airway pressure generated 100 milliseconds after an occlusion/maximal inspiratory pressure of ≤0.09 were the most accurate predictors of extubation outcome in the derivation group. In the validation group, a diaphragmatic pressure-time index of ≤0.12 and a respiratory muscle pressure-time index of ≤0.10 both had zero false-positive results, predicting with accuracy successful extubation. CONCLUSION: Composite extubation indices such as the diaphragmatic pressure-time index and the noninvasive respiratory muscle pressure-time index can accurately predict extubation outcome in preterm neonates.