Early Respiratory Physiotherapy versus an Individualized Postural Care Program for Reducing Mechanical Ventilation in Preterm Infants: A Randomised Controlled Trial

BACKGROUND

Tactile stimulation manoeuvres stimulate spontaneous breathing in preterm newborns. The aim of this study is to evaluate the effect of early respiratory physiotherapy on the need for mechanical ventilation during the first week of life in preterm infants with respiratory failure.

METHODS

This is a monocentric, randomised controlled trial. Preterm infants (gestational age ≤ 30 weeks) not intubated in the delivery room and requiring non-invasive respiratory support at birth were eligible for the study. The intervention group received early respiratory physiotherapy, while the control group received only a daily physiotherapy program (i.e., modifying the infant's posture in accordance with the patient's needs).

RESULTS

between October 2019 and March 2021, 133 preterm infants were studied, 68 infants in the study group and 65 in routine care. The study group showed a reduction in the need for mechanical ventilation (not statistically significant) and a statistically significant reduction in hemodynamically significant patent ductus arteriosus with respect to the control group (19/68 (28%) vs. 35/65 (54%), respectively, p = 0.03).

CONCLUSIONS

early respiratory physiotherapy in preterm infants requiring non-invasive respiratory support at birth is safe and has proven to be protective against haemodynamically significant PDA.

The future of neonatal lung ultrasound: Validation of an artificial intelligence model for interpreting lung scans. A multicentre prospective diagnostic study

BACKGROUND

Artificial intelligence (AI) is a promising field in the neonatal field. We focused on lung ultrasound (LU), a useful tool for the neonatologist. Our aim was to train a neural network to create a model able to interpret LU.

METHODS

Our multicentric, prospective study included newborns with gestational age (GA) ≥ 33 + 0 weeks with early tachypnea/dyspnea/oxygen requirements. For each baby, three LU were performed: within 3 h of life (T0), at 4-6 h of life (T1), and in the absence of respiratory support (T2). Each scan was processed to extract the region of interest used to train a neural network to classify it according to the LU score (LUS). We assessed sensitivity, specificity, positive and negative predictive value of the AI model's scores in predicting the need for respiratory assistance with nasal continuous positive airway pressure and for surfactant, compared to an already studied and established LUS.

RESULTS

We enrolled 62 newborns (GA = 36 ± 2 weeks). In the prediction of the need for CPAP, we found a cutoff of 6 (at T0) and 5 (at T1) for both the neonatal lung ultrasound score (nLUS) and AI score (AUROC 0.88 for T0 AI model, 0.80 for T1 AI model). For the outcome "need for surfactant therapy", results in terms of area under receiver operator characteristic (AUROC) are 0.84 for T0 AI model and 0.89 for T1 AI model. In the prediction of surfactant therapy, we found a cutoff of 9 for both scores at T0, at T1 the nLUS cutoff was 6, while the AI's one was 5. Classification accuracy was good both at the image and class levels.

CONCLUSIONS

This is, to our knowledge, the first attempt to use an AI model to interpret early neonatal LUS and can be extremely useful for neonatologists in the clinical setting.

Endobronchial ultrasound: a pictorial essay

BACKGROUND AND AIM

endobronchial ultrasound has gained widespread popularity in the last decade, becoming the primary technique for minimally invasive evaluation of the mediastinum and staging of lung cancer. Several tertiary and quaternary care institutes use this method, performed by trained and accredited specialists. Its main indications are (I) diagnosis and staging of lung cancer, (II) mediastinal lymphadenopathy diagnosis (III) sampling peripheral pulmonary lesions.

CONCLUSIONS

this manuscript aims to describe the operational potential of both convex endobronchial ultrasound probe and radial endobronchial ultrasound probe technology, focusing on lung cancer. This narrative review is complemented with by the description of peculiar clinical cases in which endobronchial ultrasound played a pivotal role in reaching the diagnosis.

Early lung ultrasound score to predict noninvasive ventilation needing in neonates from 33 weeks of gestational age: A multicentric study

OBJECTIVE

To propose an early lung ultrasound (LUS) score for the prediction of the need for respiratory assistance in newborns of gestational age (GA) ≥ 33 weeks presenting respiratory distress.

STUDY DESIGN AND SETTING

Multicenter, prospective observational study in third-level neonatal intensive care units.

PATIENT SELECTION

Infants with GA ≥ 33 + 0 weeks with respiratory distress within 3 h of life.

METHODS

Three LUS for each patient were collected: within 3 h of life (T0), at 4-6 h of life (T1), and at the resolution of symptoms (T2). The primary aim was to assess the validity of the early LUS score in predicting the need for continuous positive airway pressure (CPAP). We also evaluated the validity of the score in predicting the need for surfactant, the scores' trend in our population, and any correlation with the duration of ventilation and oxygen therapy.

RESULTS

Sixty-two patients were enrolled in the study. The mean GA was 36 weeks. The receiver operating characteristic analysis for the LUS T0 and T1 yielded area under the curves of 0.91 and 0.82 in predicting the need for CPAP, respectively. LUS score cut off of 6 (sensitivity 84.8%, specificity 86.2%) and 5 (sensitivity 66.7%, specificity 100%) were calculated at T0 and T1, respectively. We found significant correlations between LUS score and respiratory assistance, surfactant administration, and SpO₂ /FiO₂ ratio.

CONCLUSION

An early LUS score is a good noninvasive predictor of the need for respiratory assistance with CPAP and surfactant administration in newborns with GA ≥ 33 weeks.

Lowering of the Neonatal Lung Ultrasonography Score after nCPAP Positioning in Neonates over 32 Weeks of Gestational Age with Neonatal Respiratory Distress

Respiratory distress (RD) is one of the most common causes of admission to the neonatal intensive care unit. Correct diagnosis and timely intervention are crucial. Lung ultrasonography (LU) is a useful diagnostic tool for the neonatologist in the diagnosis of RD; the neonatal lung ultrasonography score (nLUS) can be used in the diagnostic process, but some authors hypothesise that it is also useful for the management of some neonatal RD. The aim of this study is to analyse the changes in nLUS score before (T0) and after (T1) the start of respiratory support with nasal CPAP in neonates over 32 weeks of age with RD. Thirty-three newborns were enrolled in this retrospective study. LU was performed before and after the start of CPAP. The median nLUS scores at T0 and T1 were 9 (IQR 7−12) and 7 (IQR 4−10), respectively, and showed a significant difference (p < 0.001). The magnitude of reduction in nLUS score, expressed as a percentage, was inversely related to the need for subsequent administration of exogenous surfactant. The study suggests the usefulness of the nLUS score in assessing the response to CPAP in neonates over 32 weeks gestational age.

The Relationship Between Maternal and Neonatal Microbiota in Spontaneous Preterm Birth: A Pilot Study

The newborn's microbiota composition at birth seems to be influenced by maternal microbiota. Maternal vaginal microbiota can be a determining factor of spontaneous Preterm Birth (SP^PTB), the leading cause of perinatal mortality. The aim of the study is to investigate the likelihood of a causal relationship between the maternal vaginal microbiota composition and neonatal lung and intestinal microbiota profile at birth, in cases of SP^PTB. The association between the lung and/or meconium microbiota with the subsequent development of bronchopulmonary dysplasia (BPD) was also investigated. Maternal vaginal swabs, newborns' bronchoalveolar lavage fluid (BALF) (1st, 3rd, 7th day of life) and first meconium samples were collected from 20 women and 23 preterm newborns with gestational age ≤ 30 weeks (12 = SP^PTB; 11 = Medically Indicated Preterm Birth-MI^PTB). All the samples were analyzed for culture examination and for microbiota profiling using metagenomic analysis based on the Next Generation Sequencing (NGS) technique of the bacterial 16S rRNA gene amplicons. No significant differences in alpha e beta diversity were found between the neonatal BALF samples of SP^PTB group and the MI^PTB group. The vaginal microbiota of mothers with SP^PTB showed a significant difference in alpha diversity with a decrease in Lactobacillus and an increase in Proteobacteria abundance. No association was found between BALF and meconium microbiota with the development of BPD. Vaginal colonization by Ureaplasma bacteria was associated with increased risk of both SP^PTB and newborns' BPD occurrence. In conclusion, an increase in α-diversity values and a consequent fall in Lactobacillus in vaginal environment could be associated to a higher risk of SP^PTB. We could identify neither a specific neonatal lung or meconium microbiota profiles in preterm infants born by SP^PTB nor a microbiota at birth suggestive of subsequent BPD development. Although a strict match has not been revealed between microbiota of SP^PTB mother-infant couples, a relationship cannot be excluded. To figure out the reciprocal influence of the maternal-neonatal microbiota and its potential role in the pathogenesis of SP^PTB and BPD further research is needed.

Weaning from the Ventilator in Bronchopulmonary Dysplasia

For the newborns needing respiratory support at 36 weeks postmenstrual age, regardless of the type of ventilation used, it is critical to take into account the mechanics properties of both airways and lungs affected by severe bronchopulmonary dysplasia (sBPD). Ventilator strategies, settings, and weaning must change dramatically after sBPD is established, but to date there is almost no high-quality evidence base supporting a specific approach to guide the optimal ventilator management and weaning in patients with sBPD. Weaning from invasive mechanical ventilation, management of the immediately postextubation period, and weaning from noninvasive ventilation in patients with sBPD are the topics covered in this chapter.

Effects of early respiratory physiotherapy on spontaneous respiratory activity of preterm infants: study protocol for a randomized controlled trial

Background

Tactile maneuvers stimulating spontaneous respiratory activity in preterm infants are recommended since birth, but data on how and how often these maneuvers are applied in clinical practice are unknown. In the last years, most preterm newborns with respiratory failure are preferentially managed with non-invasive respiratory support and by stimulating spontaneous respiratory activity from the delivery room and in neonatal intensive care unit (NICU), in order to avoid the risks of intubation and prolonged mechanical ventilation.

Methods

Preterm infants with gestational age < 31 weeks not intubated in the delivery room and requiring non-invasive respiratory support at birth will be eligible for the study. They will be randomized and allocated to one of two treatment groups: (1) the study group infants will be subject to the technique of respiratory facilitation within the first 24 h of life, according to the reflex stimulations, by the physiotherapist. The newborn is placed in supine decubitus and a slight digital pressure is exerted on a hemithorax. The respiratory facilitation technique will be performed for about three minutes and repeated for a total of 4/6 times in sequence, three times a day until spontaneous respiratory activity is achieved; thus, no respiratory support is required; (2) the control group infants will take part exclusively in the individualized postural care program. They will perform the technique of respiratory facilitation and autogenous drainage.

Objective

To evaluate the efficacy of early respiratory physiotherapy in reducing the incidence of intubation and mechanical ventilation in the first week of life (primary outcome).

Discussion

The technique of respiratory facilitation is based on reflex stimulations, applied early to preterm infant. Slight digital pressure is exerted on a “trigger point” of each hemithorax, to stimulate the respiratory activity with subsequent increase of the ipsilateral pulmonary minute ventilation and to facilitate the contralateral pulmonary expansion. This mechanism will determine the concatenation of input to all anatomical structures in relation to the area being treated, to promote spontaneous respiratory activity and reducing work of breathing, avoiding or minimizing the use of invasive respiratory support.

Trial registration

UMIN-CTR Clinical Trial UMIN000036066. Registered on March 1, 2019. Protocol 1. https://www.umin.ac.jp/ctr

Effects of High-Frequency Oscillatory Ventilation With Volume Guarantee During Surfactant Treatment in Extremely Low Gestational Age Newborns With Respiratory Distress Syndrome: An Observational Study

OBJECTIVE

To evaluate the effect of volume guarantee (VG) combined with high-frequency oscillatory ventilation (HFOV) on respiratory and other physiological parameters immediately after lung recruitment and surfactant administration in HFOV elective ventilated extremely low gestational age newborns (ELGAN) with respiratory distress syndrome (RDS).

DESIGN

Observational study.

SETTING

Tertiary neonatal intensive care unit.

PATIENTS

Twenty-two ELGANs of 25.5 ± 1.1 weeks of gestational age requiring invasive mechanical ventilation and surfactant administration for RDS during the first 6 h of life.

INTERVENTIONS

All infants intubated in delivery room, were managed with elective HFOV and received surfactant after a lung recruitment manoeuver. Eleven infants received HFOV + VG and were compared with a control group of 11 infants receiving HFOV alone. HFOV was delivered in both groups by Dräger Babylog VN500 ventilator (Dräger, Lubeck, Germany).

MAIN OUTCOME MEASURES

Variations and fluctuations of delivered high-frequency tidal volume (VT_hf), fluctuation of pressure amplitude (ΔP) and partial pressure of CO₂ (pCO₂) levels after recruitment manoeuver and immediately after surfactant administration, in HFOV + VG vs. HFOV ventilated infants.

RESULTS

There were no significant differences in the two groups at starting ventilation with or without VG. The mean applied VT_hf per kg was 1.7 ± 0.3 ml/kg in the HFOV group and 1.7 ± 0.1 ml/kg in the HFOV + VG group. Thirty minutes after surfactant administration, HFOV group had a significant higher VT_hf/Kg than HFOV + VG (2.1 ± 0.3 vs. 1.6 ± 0.1 ml/kg, p < 0.0001) with significantly lower pCO₂ levels (43.1 ± 3.8 vs. 46.8 ± 1.5 mmHg, p = 0.01), 54.4% of patients having pCO₂ below 45 mmHg. Measured post-surfactant ΔP values were higher in HFOV group (17 ± 3 cmH₂O) than in HFOV + VG group (13 ± 3 cmH₂O, p = 0.01).

CONCLUSION

HFOV + VG maintains pCO₂ levels within target range and reduces VT_hf delivered variations more consistently than HFOV alone after surfactant administration.

Oxidative and Proteolytic Inactivation of Alpha-1 Antitrypsin in Bronchopulmonary Dysplasia Pathogenesis: A Top-Down Proteomic Bronchoalveolar Lavage Fluid Analysis

The study investigates the role of the oxidative and proteolytic inactivation of alpha-1 antitrypsin (AAT) in the pathogenesis of bronchopulmonary dysplasia (BPD) in premature infants. Bronchoalveolar lavage fluid (BALF) samples were collected on the 3rd day of life from mechanically ventilated neonates with gestational age ≤ 30 weeks and analyzed without previous treatment (top-down proteomics) by reverse-phase high-performance liquid chromatography-electrospray ionization mass spectrometry. AAT fragments were identified by high-resolution LTQ Orbitrap XL experiments and the relative abundances determined by considering the extracted ion current (XIC) peak area. Forty preterm neonates were studied: 20 (50%) did not develop BPD (no-BPD group), 17 (42.5%) developed mild or moderate new-BPD (mild + moderate BPD group), and 3 (7.5%) developed severe new-BPD (severe BPD group). Eighteen fragments of AAT and a fragment of AAT oxidized at a methionine residue were identified: significantly higher values of AAT fragments 25-57, 375-418, 397-418, 144-171, and 397-418 with oxidized methionine were found in the severe BPD group. The significantly higher levels of several AAT fragments and of the fragment 397-418, oxidized in BALF of preterm infants developing BPD, underlie the central role of an imbalance between proteases and protease inhibitors in exacerbating lung injury and inducing most severe forms of BPD. The study has some limitations, and between them, the small sample size implies the need for further confirmation by larger studies.

HPLC-ESI-MS top-down analysis of salivary peptides of preterm newborns evidenced high activity of some exopeptidases and convertases during late fetal development

To have information on the proteolytic activity of convertases and exo-peptidases on human salivary proteins, this study investigated the relative amounts of the truncated proteoforms in the saliva of preterm newborns and compared them with the relative amounts measured in saliva of at-term newborns, of babies (0-10 years old) and of adults. Results indicated that convertase(s), acting on acidic proline-rich proteins and histatin 3, and carboxypeptidase(s) acting on acidic proline-rich proteins, P-C peptide, histatin 6 and statherin were many folds more active in preterm newborns than in the other groups. Conversely, the aminopeptidase responsible for the removal of the N-terminal Asp residue of statherin was not active in preterm newborns, becoming active only several months after the normal term of delivery. The high activity of convertases determined in preterm newborns suggests that it is required for the molecular events connected to the fetus development, and encourages further studies devoted to the characterization of their specific substrates.

Effect of Different Milk Diet on the Level of Fecal Calprotectin in Very Preterm Infants

Objective: To evaluate the course of fecal calprotectin (FC) in very preterm infants over the first 15 days of life in relation to the type of milk diet. Methods: This study was part of a randomized controlled trial comparing two different ways of integrating the own mother's milk (OMM) for the evaluation of feeding tolerance in very preterm infants. In infants with gestational age of ≤ 32 weeks randomized to receive preterm formula (PF group) or pasteurized donor human milk (PDHM group) as a supplement to the OMM insufficient or unavailable, FC level was planned to be measured at the first meconium passage and at days 8 and 15 of life (T0, T1, and T2, respectively). Results: FC data were available for all the 70 infants randomized, 35 in the PF group, and 35 in the PDHM group. The mean FC levels were similar in the two study groups at T0 and T1, whereas they were significantly higher in the PF group than the PDHM group at T2. FC values decreased over the first week of life in both groups and significantly increased over the second week of life only in the PF group. Conclusions: Our study demonstrates a significant increase in FC levels when PF is used as a supplement to the OMM compared to the use of PDHM. Further studies are needed to establish if the higher FC levels in infants receiving PF are the expression of a normal immunological maturation rather than an initial inflammatory process.

Gut and Lung Microbiota in Preterm Infants: Immunological Modulation and Implication in Neonatal Outcomes

In recent years, an aberrant gastrointestinal colonization has been found to be associated with an higher risk for postnatal sepsis, necrotizing enterocolitis (NEC) and growth impairment in preterm infants. As a consequence, the reasons of intestinal dysbiosis in this population of newborns have increasingly become an object of interest. The presence of a link between the gut and lung microbiome's development (gut-lung axis) is emerging, and more data show as a gut-brain cross talking mediated by an inflammatory milieu, may affect the immunity system and influence neonatal outcomes. A revision of the studies which examined gut and lung microbiota in preterm infants and a qualitative analysis of data about characteristic patterns and related outcomes in terms of risk of growing impairment, Necrotizing Enterocolitis (NEC), Bronchopulmonary Dysplasia (BPD), and sepsis have been performed. Microbiota take part in the establishment of the gut barrier and many data suggest its immune-modulator role. Furthermore, the development of the gut and lung microbiome (gut-lung axis) appear to be connected and able to lead to abnormal inflammatory responses which have a key role in the pathogenesis of BPD. Dysbiosis and the gut predominance of facultative anaerobes appear to be crucial to the pathogenesis and subsequently to the prevention of such diseases.

A modified physiologic test for bronchopulmonary dysplasia: a clinical tool for weaning from CPAP and/or oxygen-therapy the premature babies?

Background

A physiologic test for estimating BPD rate has been developed by Walsh and collaborators. Actually there are not standard criteria for weaning from CPAP and/or oxygen therapy the premature babies. Aim of this study was to verify if a physiologic test, modified respect to that developed by Walsh and collaborators for estimating BPD rate, can be used as a clinical tool for weaning the premature babies from CPAP and/or oxygen therapy.

Methods

Neonates with BW 500–1250 g and GA ≤ 32 weeks, receiving FiO₂ ≤ 0.30 by hood or CPAP, were prospectively studied at 28 days of life and at 36 weeks of postmestrual age. The test was performed in 3 steps: baseline, challenge (FiO₂ and CPAP reduction to room air) and post test (room air). Monitoring of transcutaneous CO₂ was added to SpO₂ and the newborns passing the test were left in room air.

Results

Six of 23 tested babies (26%) passed the challenge at 28 days of life, 4 of 10 tested babies (40%) passed the challenge at 36 weeks. Median values of SpO₂ were significantly higher in the neonates passing the test, respect to the failing patients. At the same time median values of TcPCO₂ were significantly higher in the latter babies.

Conclusion

TcPCO₂ monitoring appeared to be a new useful parameter for failure prediction of weaning. The test represented a clinical guide because the newborns passing it were left in room air.

Oxidative Stress and Bronchopulmonary Dysplasia: Evidences From Microbiomics, Metabolomics, and Proteomics

Bronchopulmonary dysplasia is a major issue affecting morbidity and mortality of surviving premature babies. Preterm newborns are particularly susceptible to oxidative stress and infants with bronchopulmonary dysplasia have a typical oxidation pattern in the early stages of this disease, suggesting the important role of oxidative stress in its pathogenesis. Bronchopulmonary dysplasia is a complex disease where knowledge advances as new investigative tools become available. The explosion of the "omics" disciplines has recently affected BPD research. This review focuses on the new evidence coming from microbiomics, metabolomics and proteomics in relation to oxidative stress and pathogenesis of bronchopulmonary dysplasia. Since the pathogenesis is not yet completely understood, information gained in this regard would be important for planning an efficacious prevention and treatment strategy for the future.

Nasal high-frequency oscillatory ventilation and CO2 removal: A randomized controlled crossover trial

OBJECTIVE

To compare short-term application of nasal high-frequency oscillatory ventilation (nHFOV) with nasal continuous positive airway pressure (nCPAP).

WORKING HYPOTHESIS

nHFOV improves CO₂ removal with respect to nCPAP in preterm infants needing noninvasive respiratory support and persistent oxygen supply after the first 72 h of life.

STUDY DESIGN

Multicenter non-blinded prospective randomized crossover study.

PATIENT SELECTION

Thirty premature infants from eight tertiary neonatal intensive care units, of mean ± SD 26.4 ± 1.8 weeks of gestational age and 921 ± 177 g of birth weight.

METHODOLOGY

Infants were randomly allocated in a 1:1 ratio to receive a starting treatment mode of either nCPAP or nHFOV delivered by the ventilator CNO (Medin, Germany), using short binasal prongs of appropriate size. A crossover design with four 1-h treatment periods was used, such that each infant received both treatments twice. The primary outcome was the mean transcutaneous partial pressure of CO₂ (TcCO₂ ) value during the 2-h cumulative period of nHFOV compared with the 2-h cumulative period of nCPAP.

RESULTS

Significantly lower TcCO₂ values were observed during nHFOV compared with nCPAP: 47.5 ± 7.6 versus 49.9 ± 7.2 mmHg, respectively, P = 0.0007. A different TcCO₂ behavior was found according to the random sequence: in patients starting on nCPAP, TcCO₂ significantly decreased from 50.0 ± 8.0 to 46.6 ± 7.5 mmHg during nHFOV (P = 0.001). In patients starting on nHFOV, TcCO₂ slightly increased from 48.5 ± 7.8 to 49.9 ± 6.7 mmHg during nCPAP (P = 0.13).

CONCLUSIONS

nHFOV delivered through nasal prongs is more effective than nCPAP in improving the elimination of CO₂ .

Extubation from high-frequency oscillatory ventilation in extremely low birth weight infants: a prospective observational study

OBJECTIVE

To evaluate if weaning from high-frequency oscillatory ventilation (HFOV) directly to a non-invasive mode of respiratory support is feasible and results in successful extubation in extremely low birth weight (ELBW) infants.

DESIGN

Prospective observational study.

SETTING

Tertiary neonatal intensive care unit.

PATIENTS

One hundred and eight ELBW infants of 26.2±1.4 weeks of gestational age (GA) directly extubated from HFOV.

INTERVENTIONS

All infants were managed with elective HFOV and received surfactant after a recruitment HFOV manoeuvre. Extubation was attempted at mean airways pressure (MAP) ≤6 cm H₂O with FiO₂ ≤0.25. After extubation, all infants were supported by nasal continuous positive airway pressure (6-8 cm H₂O).

MAIN OUTCOME MEASURES

Extubation failure (clinical deterioration requiring reintubation) was defined as shorter than 7 days.

RESULTS

Ninety patients (83%) were successfully extubated and 18 (17%) required reintubation. No significant differences were found between the two groups in terms of birth weight, day of life and weight at the time of extubation. Multivariable analysis showed that GA (OR 1.71; 95% CI 1.04, 2.08) and higher MAP prior to surfactant (OR 1.51; 95% CI 1.06, 2.15) were associated with successful extubation.

CONCLUSIONS

In ELBW infants, direct extubation from HFOV at MAP ≤6 cm H₂O with FiO₂ ≤0.25 is feasible. Our extubation success rate (83%) is higher than conventional mechanical ventilation in this very vulnerable class of infants.

Management of pneumothorax in hemodynamically stable preterm infants using high frequency oscillatory ventilation: report of five cases

Background

Despite an increased use of non-invasive ventilatory strategies and gentle ventilation, pneumothorax remains a common complication in preterm infants. The ventilator management of infants with air leaks remains challenging in terms of both prevention and treatment. Recently the safety and efficacy of expectant management avoiding chest tube drainage to treat large air leak in preterm infants hemodynamically stable has been reported.

Case presentation

In the present study, we report five cases of preterm infants with birth weight ≤ 1250 g affected by respiratory distress syndrome and treated with nasal continuous positive airway pressure as first intention. They were intubated for worsening of respiratory distress with increasing oxygen requirement and concomitant increase of respiratory rate and P_CO2 values due to occurrence of pneumothorax, and they were successfully treated using high-frequency oscillatory ventilation without chest tube insertion.

Conclusion

In our experience high-frequency oscillatory ventilation provided a conservative management of a significant pneumothorax in preterm newborns hemodynamically stable and requiring mechanical ventilation. This approach allowed us to avoid the increasing of air leak and the insertion of chest tube drainage and all the subsequent associated risks.

Fetal Doppler velocimetry and bronchopulmonary dysplasia risk among growth-restricted preterm infants: an observational study

OBJECTIVE

To investigate whether fetal growth restriction (FGR) diagnosis, based on pathological prenatal fetal Doppler velocimetry, is associated with bronchopulmonary dysplasia (BPD) independently of being small for gestational age (SGA) per se at birth among very preterm infants.

DESIGN

Prospective, observational study. FGR was defined as failing fetal growth in utero and fetal Doppler velocimetry abnormalities.

SETTING

Policlinico Universitario Agostino Gemelli, Roma, Italy.

PATIENTS

Preterm newborns with gestational age ≤30 weeks and birth weight (BW) ≤1250 g.

MAIN OUTCOME MEASURES

Bronchopulmonary dysplasia.

RESULTS

In the study period, 178 newborns were eligible for the study. Thirty-nine infants (22%) were considered fetal growth-restricted infants. Among the 154 survived babies at 36 weeks postmenstrual age, 12 out of 36 (33%) of the FGR group developed BPD versus 8 out of 118 (7%) of the NO-FGR group (p<0.001). BPD rate was sixfold higher among the SGA-FGR infants compared with the SGA-NO-FGR infants. In a multivariable model, FGR was significantly associated with BPD risk (OR 5.1, CI 1.4 to 18.8, p=0.01), independently from BW z-score that still remains a strong risk factor (OR 0.5, CI 0.3 to 0.9, p=0.01).

CONCLUSION

Among SGA preterm infants, BPD risk dramatically increases when placenta dysfunction is the surrounding cause of low BW. Antenatal fetal Doppler surveillance could be a useful tool for studying placenta wellness and predicting BPD risk among preterm babies. Further research is needed to better understand how FGR affects lung development.

Efficacy of a new technique - INtubate-RECruit-SURfactant-Extubate - "IN-REC-SUR-E" - in preterm neonates with respiratory distress syndrome: study protocol for a randomized controlled trial

Background

Although beneficial in clinical practice, the INtubate-SURfactant-Extubate (IN-SUR-E) method is not successful in all preterm neonates with respiratory distress syndrome, with a reported failure rate ranging from 19 to 69 %. One of the possible mechanisms responsible for the unsuccessful IN-SUR-E method, requiring subsequent re-intubation and mechanical ventilation, is the inability of the preterm lung to achieve and maintain an “optimal” functional residual capacity. The importance of lung recruitment before surfactant administration has been demonstrated in animal studies showing that recruitment leads to a more homogeneous surfactant distribution within the lungs. Therefore, the aim of this study is to compare the application of a recruitment maneuver using the high-frequency oscillatory ventilation (HFOV) modality just before the surfactant administration followed by rapid extubation (INtubate-RECruit-SURfactant-Extubate: IN-REC-SUR-E) with IN-SUR-E alone in spontaneously breathing preterm infants requiring nasal continuous positive airway pressure (nCPAP) as initial respiratory support and reaching pre-defined CPAP failure criteria.

Methods/design

In this study, 206 spontaneously breathing infants born at 24⁺⁰–27⁺⁶ weeks’ gestation and failing nCPAP during the first 24 h of life, will be randomized to receive an HFOV recruitment maneuver (IN-REC-SUR-E) or no recruitment maneuver (IN-SUR-E) just prior to surfactant administration followed by prompt extubation. The primary outcome is the need for mechanical ventilation within the first 3 days of life. Infants in both groups will be considered to have reached the primary outcome when they are not extubated within 30 min after surfactant administration or when they meet the nCPAP failure criteria after extubation.

Discussion

From all available data no definitive evidence exists about a positive effect of recruitment before surfactant instillation, but a rationale exists for testing the following hypothesis: a lung recruitment maneuver performed with a step-by-step Continuous Distending Pressure increase during High-Frequency Oscillatory Ventilation (and not with a sustained inflation) could have a positive effects in terms of improved surfactant distribution and consequent its major efficacy in preterm newborns with respiratory distress syndrome. This represents our challenge.

Trial registration

ClinicalTrials.gov identifier: NCT02482766. Registered on 1 June 2015.

Chrono-proteomics of human saliva: variations of the salivary proteome during human development

An important contribution to the variability of any proteome is given by the time dimension that should be carefully considered to define physiological modifications. To this purpose, whole saliva proteome was investigated in a wide age range. Whole saliva was collected from 17 preterm newborns with a postconceptional age at birth of 178-217 days. In these subjects sample collection was performed serially starting immediately after birth and within about 1 year follow-up, gathering a total of 111 specimens. Furthermore, whole saliva was collected from 182 subjects aged between 0 and 17 years and from 23 adults aged between 27 and 57 years. The naturally occurring intact salivary proteome of the 316 samples was analyzed by low- and high-resolution HPLC-ESI-MS platforms. Proteins peculiar of the adults appeared in saliva with different time courses during human development. Acidic proline-rich proteins encoded by PRH2 locus and glycosylated basic proline-rich proteins encoded by PRB3 locus appeared following 180 days of postconceptional age, followed at 7 months (±2 weeks) by histatin 1, statherin, and P-B peptide. The other histatins and acidic proline-rich proteins encoded by PRH1 locus appeared in whole saliva of babies from 1 to 3 weeks after the normal term of delivery, S-type cystatins appeared at 1 year (±3 months), and basic proline-rich proteins appeared at 4 years (±1 year) of age. All of the proteinases involved in the maturation of salivary proteins were more active in preterm than in at-term newborns, on the basis of the truncated forms detected. The activity of the Fam20C kinase, involved in the phosphorylation of various proteins, started around 180 days of postconceptional age, slowly increased reaching values comparable to adults at about 2 years (±6 months) of age. Instead, MAPK14 involved in the phosphorylation of S100A9 was fully active since birth also in preterm newborns.

Lung recruitment strategies and surfactant in neonatal intensive care unit

Several studies in the lamb model have shown that hyperinflation of the lungs early in life may cause a blunted response to surfactant with signs of lung injury and any attempt to recruit lung volume in the surfactant deficient preterm infant by large lung inflations at birth should be potentially dangerous. As regards the situation when surfactant is given later, as rescue treatment for established RDS, the evidence for a clinically beneficial effect of a recruitment maneuver is yet insufficient and, hopefully, future studies will gather more data on this aspect.

Adrenocortical insufficiency is not a problem in preterm infants treated with antifungal prophylaxis with fluconazole

AIM

Fluconazole prophylaxis of invasive fungal infections is a cornerstone of neonatal care, but in vitro studies have shown that it inhibits corticosteroid production. This study assessed whether preterm infants demonstrated an association between fluconazole administration, and its duration, and symptoms of adrenocortical insufficiency.

METHODS

We compared two groups who were treated before and after we introduced the use of fluconazole to our neonatal intensive care unit. Infants with a gestational age of ≤27 weeks or with a birth weight of ≤750 g were considered for the retrospective analysis. In order to assess whether the duration of prophylaxis was related to adrenocortical insufficiency, regression models were performed in all preterm infants in the fluconazole group.

RESULTS

The fluconazole group (n = 37) and nonfluconazole group (n = 41) were compared. No differences were found in the percentage of infants with symptoms of adrenocortical insufficiency, such as hypotension or need of vasopressor therapy. The incidence of hypotension and the use of vasopressor therapy were not related to duration of fluconazole prophylaxis.

CONCLUSION

Fluconazole and it duration were not associated with the incidence of symptoms related to adrenocortical insufficiency. Further prospective trials are needed to better define the relationship between fluconazole and adrenocortical insufficiency.

Top-down platform for deciphering the human salivary proteome

Proteomic platforms can be classified in bottom-up strategies, which analyze the sample after proteolytic digestion, and top-down strategies, which analyze the intact naturally occurring proteome. Bottom-up platforms are high-throughput because they can investigate a large number of proteins, regardless of their dimension. Nonetheless, information on post-translational modifications (PTMs) can be lost, especially those regarding naturally occurring cleavages and alternative splicing. Top-down platforms cannot cover vast proteomes, however, they can disclose subtle structural variations occurring during protein maturation and allow label-free relative quantifications in an unlimited number of samples. A repertoire of 256 masses belonging to naturally occurring proteins and peptides consistently detected by RP-HPLC-ESI-MS analysis of the acidic soluble fraction of human whole saliva is presented in this study. Of them, 233 have been identified, while 23 are still pending for the definitive characterization. The present review reports average and mono-isotopic masses of the peptides and proteins detected, RP-HPLC elution times, PTMs, origin and quali-quantitative variations observed in several physiological and pathological conditions. The information reported can be a reference for users of top-down RP-HPLC-ESI-MS proteomic platforms applied to the study of the human salivary proteome as well as of other human bodily fluids.

Top-down HPLC-ESI-MS detection of S-glutathionylated and S-cysteinylated derivatives of cystatin B and its 1-53 and 54-98 fragments in whole saliva of human preterm newborns

Analysis by a HPLC-ESI-MS top-down proteomic platform of specimens of human preterm newborn whole saliva evidenced high relative amounts of cystatin B and its S-glutathionylated,S-cysteinylated, and S-S 2-mer (on Cys(3)) derivatives, decreasing as a function of postconceptional age (PCA). The percentage of S-unmodified cystatin B was higher than the S-modified isoforms in the early PCA period, differently from adults where cystatin B was detectable only as S-modified derivatives. The percentage of S-modified derivatives increased as a function of PCA, reaching at the normal term of delivery values similar to those determined in at-term newborns, babies, and adults. Moreover, in the early PCA period, high relative amounts of the 1-53 and 54-98 cystatin B fragments were detected, decreasing as a function of PCA and disappearing at the normal term of delivery. In agreement with intact cystatin B, fragment 1-53 was detectable as S-unmodified and S-modified derivatives, and their percentages changed accordingly with the percentages of intact proteins, suggesting that the fragmentation process could be subsequent to and independent from the S-modification of the protein. This study highlights specific enzymatic activity in the oral cavity of preterm newborns not present in at-term newborns and adults, which can be a clue to specialized pathways occurring during fetal oral development.

Efficacy of exogenous surfactant during conventional and high-frequency oscillatory ventilation in preterm infants with RDS

INTRODUCTION

The immediate effects of exogenous surfactant on lung volume and hemodynamics in preterm infants have been poorly studied.

MATERIALS AND METHODS

Lung volume, SpO2, perfusion index, regional SO2, transcutaneous partial pressure of CO2 were simultaneously monitored and recorded ten minutes after surfactant tracheal instillation in elective HFOV ventilated preterm infants with RDS.

OUTCOMES

Despite a reduction in gas exchange during the first 5 minutes post surfactant instillation, most likely dependent on airway obstruction, lung volume increases rapidly in HFOV preterm infants with RDS. After 5 minutes from administration of surfactant, lung volume, gas exchange and PI reach stable values and CDP can be safely reduced.

Target fraction of inspired oxygen during open lung strategy in neonatal high frequency oscillatory ventilation: a retrospective study

BACKGROUND

There is no agreement to define the target FiO2 to adopt in the lung recruitment phase during HFOV in preterm infants. We report our experience of an optimal lung volume strategy (OLVS), defined as FiO2≤0.25 during the recruitment phase, in a cohort of neonates with gestational age (GA) ≤27 weeks treated with elective HFOV for respiratory distress syndrome (RDS) between July 2006 and September 2008.

METHODS

FiO2 used during the recruitment phase was different according to physician' evaluation. 51 newborns were then divided into two groups: patients reaching FiO2≤0.25 (OLVS Group, N.=28), and patients reaching FiO2>0.25 (No-OLVS Group, N.=23).

RESULTS

Prior to surfactant administration OLVS Group, respect to No-OLVS Group, received a significantly higher continuous distending pressure (CDP): 12.8±1.1 cmH2O vs 11.2±1.3 cmH2O (P<0.0001) and a significantly lower FiO2: 0.25±0.01 vs 0.35±0.06 (P<0.0001). A multivariate modeling approach confirmed that OLVS was significantly associated to the need for less surfactant doses (OR 0.19[95% CI 0.05-0.84]), a decreased risk of ductus arteriosus surgically ligated (OR 0.13[95% CI 0.02-0.86]) and to a lower number of ventilation hours before extubation: -152 (95% CI -284- -20).

CONCLUSION

OLVS to fully recruit the lungs achieving FiO2≤0.25 during elective HFOV is associated with better short-term pulmonary outcomes respect to a strategy where the patients received a FiO2>0.25 during the recruitment phase. Utilizing HFOV in this way provides a more effective means to recruit and protect acutely injured lungs.

Effectiveness of treatment with surfactant in premature infants with respiratory failure and pulmonary infection

INTRODUCTION

Surfactant inactivation is present in neonatal pneumonia.

MATERIALS AND METHODS

One hundred thirty-nine preterm babies with Birth Weight (BW) < or = 1250 grams were studied and subdivided in two groups: RDS Group, with a diagnosis of "simple" RDS (N 80) and RDS with Pneumonia Group, consisting of babies with a diagnosis of RDS and a positive BALF culture in the first 24-48 h of life (N 59).

OUTCOMES

Surfactant administration seems less effective in the latter group, because a significantly higher number of infants needed a second dose of surfactant, compared to the patients suffering from RDS alone. (www.actabiomedica.it).

The surprising composition of the salivary proteome of preterm human newborn

Saliva is a body fluid of a unique composition devoted to protect the mouth cavity and the digestive tract. Our high performance liquid chromatography (HPLC)-electrospray ionization-MS analysis of the acidic soluble fraction of saliva from preterm human newborn surprisingly revealed more than 40 protein masses often undetected in adult saliva. We were able to identify the following proteins: stefin A and stefin B, S100A7 (two isoforms), S100A8, S100A9 (four isoforms), S100A11, S100A12, small proline-rich protein 3 (two isoforms), lysozyme C, thymosins β(4) and β(10), antileukoproteinase, histone H1c, and α and γ globins. The average mass value reported in international data banks was often incongruent with our experimental results mostly because of post-translational modifications of the proteins, e.g. acetylation of the N-terminal residue. A quantitative label-free MS analysis showed protein levels altered in relation to the postconceptional age and suggested coordinate and hierarchical functions for these proteins during development. In summary, this study shows for the first time that analysis of these proteins in saliva of preterm newborns might represent a noninvasive way to obtain precious information of the molecular mechanisms of development of human fetal oral structures.

Early mannan detection in bronchoalveolar lavage fluid with preemptive treatment reduces the incidence of invasive Candida infections in preterm infants

BACKGROUND

Candida colonization is an important predictor for development of invasive fungal infection (IFI). We investigated whether early detection of Candida mannan (Mn) in bronchoalveolar lavage fluid (BALF) reduces IFI among preterm infants.

METHODS

We conducted an observational study of infants with gestational age of < or =28 weeks, where a group undergoing Candida surveillance cultures (pre-Mn detection group) was compared with a group defined after the initiation of routine use of Candida Mn detection in BALF (Mn detection group). Antifungal treatment was started based on positive microbiologic (surveillance culture or Mn-antigen assay) results.

RESULTS

No significant differences were detected when the groups were compared for several predictors of IFI. IFI was observed for 12 (23%) of 51 infants in the pre-Mn detection group, and for 0 (0%) of 29 infants in the Mn detection group (P = 0.003). Surveillance cultures in the pre-Mn detection group became positive at 15.0 +/- 7.2 days after birth, whereas the mean age at time of positive Mn antigen results in the Mn detection group was 4.3 +/- 3.1 days (P < 0.0001). Among 16 infants positive for surveillance cultures, 12 (75%) developed IFI (P < 0.0001).

CONCLUSIONS

This study suggests that Candida Mn detection in BALF may be useful for earlier identification and preemptive therapy targeting preterm infants at high risk of IFI.

Correlation of levels of alpha-defensins determined by HPLC-ESI-MS in bronchoalveolar lavage fluid with the diagnosis of pneumonia in premature neonates

The presence of alpha-defensins in bronchoalveolar lavage fluid (BALF) was investigated in a cohort of preterm newborns with gestational age (GA) < or =30 wk. Specimens were collected during the first week of life from 24 preterm neonates mechanically ventilated. The studied population was divided into two groups: pneumonia group of nine neonates suffering from pulmonary infection (GA: 26.1 +/- 2.1 wk; birth weight: 787.4 +/- 309.9 g), with or without associated bloodstream infection, and nonpneumonia group of 15 neonates (GA: 27.7 +/- 2.0 wk; birth weight: 1019.0 +/- 319.8 g). BALF culture was positive for CONS (n = 5), Staphylococcus aureus (n = 1), and Candida spp (n = 3). BALF samples were analyzed by HPLC-electrospray Ionization-mass spectrometer. The alpha-defensins 1-4 concentration, absolute and differential white cells count were measured. Relative amounts of alpha-defensins 1-4 and the absolute number of neutrophils were found significantly higher in the pneumonia group with respect to the nonpneumonia group (p < 0.05). Moreover, positive significant correlations between the number of neutrophils and the alpha-defensins 1-3 levels were observed. In conclusion, our data show that preterm newborns, also at the lower GA, are able to produce alpha-defensins, underlining that their innate defense system is already active before the at-term delivery date.

Proteomics and neonatal infection

Antimicrobial peptides plays an important role in the host innate defence network, even in humans. Recent studies demonstrated the capacity of human airways epithelial cells to synthesize antimicrobial peptides, and their multifunctional role in the primary immunity. The presence of ct-defensins in bronchoalveolar lavage fluid (BALF) was investigated in a cohort of preterm newborns with gestational age (GA) < or =30 weeks. BALF samples were analysed by High Performance Liquid Chromatography Electrospray Ionization Mass Spectrometer. Our data show that preterm newborns, also at the lower GA, are able to produce defenses, underlining that their innate defence system is already active before the at-term delivery date.

Bronchoalveolar lavage fluid peptidomics suggests a possible matrix metalloproteinase-3 role in bronchopulmonary dysplasia

BACKGROUND

Bronchoalveolar lavage fluid (BALF) is an important diagnostic source to investigate molecular changes occurring in lung disorders. The objective of this study was to assess and compare the peptidomic profiles of BALF from premature neonates with and without bronchopulmonary dysplasia (BPD).

METHODS

Samples were obtained on the 3rd day of life from 34 neonates with gestational age <or=32 weeks. Two pools of samples from patients with and without BPD were analyzed by high performance liquid chromatography. Several differentially expressed peptides were collected and sequenced. Moreover, samples from single donors were analyzed by liquid chromatography-electrospray ionization mass spectrometry to define the molecular mass values of various peptides and to quantify their expression. Levels of some matrix metalloproteinases and their tissue inhibitors were also determined in single samples.

RESULTS

Neonates of the BPD group (N = 16) showed significantly lower mean gestational age and birth weight with respect to the no-BPD group (N = 18; P < 0.0001). Levels of six peptides were significantly higher in BPD patients (P < 0.05). Two of them were identified as the albumin fragments 1-21 (2,428 Da) and 399-406 (956 Da). Levels of matrix metalloproteinase-3 (MMP-3) enzyme probably involved in albumin fragment generation were also significantly higher in the BPD group compared to the no-BPD group (P < 0.05), whereas the levels of tissue inhibitor of metalloproteinases-1 were significantly lower (P < 0.05). Levels of albumin fragments and MMP-3 showed a significant correlation (P < 0.05).

CONCLUSIONS

This study shows that proteomic techniques can be applied to investigate the involvement of proteolytic enzymes on the airways of mechanically ventilated premature infants.

Epithelial lining fluid neutrophil-gelatinase-associated lipocalin levels in premature newborns with bronchopulmonary dysplasia and patency of ductus arteriosus

Patency of the ductus arteriosus (PDA) and bronchopulmonary dysplasia (BPD) development represent severe affections for premature newborns, therefore the research of early markers for these two conditions is really important. The aim of this study is to analyze epithelial lining fluid (ELF) Neutrophil-gelatinase-associated lipocalin (NGAL) levels for prediction of lung injury or possible involvement of this molecule in PDA. Only scarce and contrasting results have previously been published in this field. In contrast, this molecule, included in a large macromolecular complex together with matrix metalloproteinase-9 (MMP-9), is considered an acceptable marker of infectious/inflammatory processes, cancer monitoring and induction of apoptotic pathway. NGAL was detected in 28 pre-term newborns by means of a commercially available kit in bronchoalveolar lavage fluid (BALF). The results have been corrected to ELF levels, by the urea method, to eliminate bias due to BALF collection. ELF NGAL levels were found significantly increased both in infants developing BPD or in those affected by PDA. By means of multivariate logistic regression analysis the significances were confirmed after adjusting for possible interfering variables such as gestational age and concomitant presence of both PDA and BPD. Our results stress the involvement of NGAL in the mechanisms leading to BPD and also suggest a possible association with PDA, which is often linked to prematurity and BPD development, probably due to the involvement of inflammatory and angiogenetic processes in both pathologies.

[Use of Meropenem in preterm newborns. Survey of the literature and case series]

AIM

The aim of this paper was to evaluate usefulness and safety of Meropenem in severe infections in neonatal intensive care unit (NICU) patients. New broad spectrum carbapenem class of -lactam antibiotics has been investigated for the treatment of a wide range of infections, including nosocomial infections with cephalosporin-resistant pathogens, an emergent problem in NICU, and meningitis. Meropenem represents the first cabapenem-class that has received Food and Drug Administration (FDA) approval for use in children 3 months of age and older. The pharmacokinetics of Meropenem has been well studied in preterm neonates.

METHODS

We report the use of Meropenem in 26 neonates with median gestational age (GA) of 27 weeks (25-32) and median birth weight of 940 g (510-1900), with severe infections due to Gram-negative or Gram-positive organisms, from 2001 to 2004. The median postnatal age was 21 days (4-75). Meropenem was administrated intravenously in 30 min at dosage of 20 mg/kg every 12 h (every 8 h in Pseudomonas Aeruginosa infections).

RESULTS

In all cases Meropenem has been used as second choice. No adverse effects (eosinophilia, trombocytosis or thrombocytopenia, increase in liver enzyme, increase in creatinine, diarrhea, vomiting and seizures) were observed. Clinical and bacterial response was ontaine in all cases but one.

CONCLUSIONS

This report suggests that Meropenem may be a useful and safe antimicrobial agent in neonatal infections caused by resistant organisms and in meningitis. Further studies are needed to confirm these results.

Mannose-binding lectin polymorphisms and pulmonary outcome in premature neonates: a pilot study

OBJECTIVE

Mannose-binding lectin (MBL2) is a collectin molecule able to activate the complement system and the subsequent inflammatory mechanisms. Several MBL2 genetic variants have been described, including the six variants studied in this report, which are those analyzed in most detail in the medical literature.

DESIGN

The present study analyzes the prevalence of MBL2 gene variants in preterm newborns and associates individual genotypes with pulmonary outcome variables. All polymorphisms were analyzed by means of a commercially available reverse dot-blot kit.

SETTING

Tertiary neonatal intensive care unit.

PATIENTS AND PARTICIPANTS

Seventy-five consecutive preterm newborns.

MEASUREMENTS AND RESULTS

Two variants were particularly analyzed: -550G > C and R52C. The first one is known to be associated with lower protein synthesis when included in specific haplotypes. The homozygous and heterozygous -550G > C mutations were significantly associated with protective effects regarding different lung outcome variables, including shorter duration of mechanical ventilation, hours of continuous positive airway pressure and lower number of hemotransfusions. In contrast, the heterozygous R52C mutation was associated with unfavorable outcome, including higher bronchopulmonary dysplasia prevalence. Multivariate logistic regression analysis showed that these associations were independent of gestational age and birth weight. In addition, four groups of patients were defined on the basis of haplotype combinations. Those known to be associated with low serum MBL2 levels were linked to a better outcome in terms of factors such as hours of mechanical ventilation, continuous positive airway pressure, number of hemotransfusions and bronchopulmonary disease development.

CONCLUSIONS

The four haplotype combination groups may have a potential diagnostic use as opposite risk factors for lung disease of prematurity.

[Pulmonary infections in preterm newborns]

AIM

The aim of this study was to evaluate retrospectively the incidence and etiology of connatal pneumonia and ventilator-associated pneumonia (VAP) in preterm newborns who had birth weight = or < 1250 g and required intubation for at least 12 h.

METHODS

We have reported data about preterm newborns who had birth weight = or < 1250 g and required intubation for at least 12 h with diagnosis of connatal pneumonia and VAP, admitted to the neonatal intensive care unit from 1994 to 2004. We divided these 11 years into 4 periods. For each period we determined etiology associated with connatal pneumonia or VAP.

RESULTS

A total of 417 patients were studied; 311 (74.6%) required mechanical ventilation (MV) for more than 48 h (the least for the diagnosis of VAP). Connatal pneumonia occurred in 35/417 patients (8.4%). VAP incidence did not change over time showing a slight increase in the last 2 years (from 27% to 33%). Mycoplasma and Chlamydia as causative organisms of connatal pneumonia dissapear during years. Gram-negative micro-organisms were isolated more frequently in last years in VAP episodes.

CONCLUSIONS

The incidence of VAP does not decrease over time although length of MV was reduced. Additional studies are needed to improve criteria for the diagnosis and prevention of VAP in NICU patients.