Impact on cerebral hemodynamics of the use of volume guarantee combined with high frequency oscillatory ventilation in a neonatal animal respiratory distress model.

High-frequency oscillatory ventilation (HFOV) is an alternative to conventional mechanical ventilation (CMV). Recently, the use of volume guarantee (VG) combined with HFOV has been suggested as a safe strategy capable of reducing the damage induced by ventilation in immature lungs. However, the possible impact of this new ventilation technique on cerebral hemodynamics is unknown. To evaluate the cerebral hemodynamics effect of HFOV combined with VG in an experimental animal model of neonatal respiratory distress syndrome (RDS) due to surfactant deficiency compared with HFOV and CMV+VG (control group). Eighteen newborn piglets were randomized, before and after the induction of RDS by bronchoalveolar lavage, into 3 mechanical ventilation groups: CMV, HFOV and HFOV with VG. Changes in cerebral oxygen transport and consumption and cerebral blood flow were analyzed by non-invasive regional cerebral oxygen saturation (CrSO2), jugular venous saturation (SjO2), the calculated cerebral oxygen extraction fraction (COEF), the calculated cerebral fractional tissue oxygen extraction (cFTOE) and direct measurement of carotid artery flow. To analyze the temporal evolution of these variables, a mixed-effects linear regression model was constructed. After randomization, the following statistically significant results were found in every group: a drop in carotid artery flow: at a rate of -1.7 mL/kg/min (95% CI: -2.5 to -0.81; p < 0.001), CrSO2: at a rate of -6.2% (95% CI: -7.9 to -4.4; p < 0.001) and SjO2: at a rate of -20% (95% CI: -26 to -15; p < 0.001), accompanied by an increase in COEF: at a rate of 20% (95% CI: 15 to 26; p < 0.001) and cFTOE: at a rate of 0.07 (95% CI: 0.05 to 0.08; p < 0.001) in all groups. No statistically significant differences were found between the HFOV groups. CONCLUSION: No differences were observed at cerebral hemodynamic between respiratory assistance in HFOV with and without VG, being the latter ventilatory strategy equally safe. WHAT IS KNOWN: • Preterm have a situation of fragility of cerebral perfusion wich means that any mechanical ventilation strategy can have a significant influence. High-frequency oscillatory ventilation (HFOV) is an alternative to conventional mechanical ventilation (CMV). Recently, the use of volume guarantee (VG) combined with HFOV has been suggested as a safe strategy capable of reducing the damage induced by ventilation in immature lungs. Several studies have compared CMV and HFOV and their effects at hemodynamic level. It is known that the use of high mean airway pressure in HFOV can cause an increase in pulmonary vascular resistance with a decrease in thoracic venous return. WHAT IS NEW: • The possible impact of VAFO + VG on cerebral hemodynamics is unknown. Due the lack of studies and the existing controversy, we have carried out this research project in an experimental animal model with the aim of evaluating the cerebral hemodynamic repercussion of the use of VG in HFOV compared to the classic strategy without VG.

Effect of a new respiratory care bundle on bronchopulmonary dysplasia in preterm neonates.

The development of devices that can fix the tidal volume in high-frequency oscillatory ventilation (HFOV) has allowed for a significant improvement in the management of HFOV. At our institution, this had led to the earlier use of HFOV and promoted a change in the treatment strategy involving the use of higher frequencies (above 15 Hz) and lower high-frequency tidal volumes (VThf). The purpose of this observational study was to assess how survival without bronchopulmonary dysplasia grades 2 and 3 (SF-BPD) is influenced by these modifications in the respiratory strategy applied to preterm infants (gestational age < 32 weeks at birth) who required mechanical ventilation (MV) in the first 3 days of life. We compared a baseline period (2012-2013) against a period in which this strategy had been fully implemented (2016-2017). A total of 182 patients were exposed to MV in the first 3 days of life being a higher proportion on HFOV at day 3 in the second period 79.5% (n 35) in 2016-2017 vs 55.4% (n 31) in 2012-2013. After adjusting for perinatal risk factors, the second period is associated with an increased rate of SF-BPD (OR 2.28; CI 95% 1.072-4.878); this effect is more evident in neonates born at a gestational age of less than 29 weeks (OR 4.87; 95% CI 1.9-12.48).Conclusions : The early use of HFOV combined with the use of higher frequencies and very low VT was associated with an increase in the study population's SF-BPD. What is Known: • High-frequency ventilation with volume guarantee improve ventilation stability and has been shown to reduce lung damage in animal models. What is New: • The strategy of an earlier use of high-frequency oscillatory ventilation combined with the use of higher frequencies and lower tidal volume is associated to an increase in survival without bronchopulmonary dysplasia in our population of preterm infants.

DCO2/PaCO2 correlation on high-frequency oscillatory ventilation combined with volume guarantee using increasing frequencies in an animal model.

To examine the correlation DCO2/PaCO2 on high-frequency oscillatory ventilation (HFOV) combined with volume guarantee (VG) throughout increasing frequencies in two different respiratory conditions, physiological and low compliance. Neonatal animal model was used, before and after a bronchoalveolar lavage (BAL). HFOV combined with VG was used. The frequency was increased from 10 to 20 Hz, and high-frequency tidal volume (VThf) was gradually decreased maintaining a constant DCO2. Arterial partial pressure of carbon dioxide (PaCO2) was evaluated after each frequency and VThf change. Six 2-day-old piglets were studied. A linear decrease in PaCO2 was observed throughout increasing frequencies in both respiratory conditions while maintaining a constant DCO2, showing a significant difference between the initial PaCO2 (at 10 Hz) and the PaCO2 obtained at 18 and 20 Hz. A new DCO2 equation (corrected DCO2) was calculated in order to better define the correlation between DCO2 and the observed PaCO2.Conclusion: The correlation DCO2/PaCO2 throughout increasing frequencies is not linear, showing a greater CO2 elimination efficiency at higher frequencies, in spite of maintaining a constant DCO2. So, using frequencies close to the resonant frequency of the respiratory system on HFOV combined with VG, optimizes the efficiency of gas exchange.What is Known: • The efficacy of CO2removal during high-frequency oscillatory ventilation (HFOV), described as the diffusion coefficient of CO2(DCO2) is related to the square of the high-frequency tidal volume (VThf) and the frequency (f), expressed as DCO2= VThf2× f.What is New: • The correlation between DCO2and PaCO2throughout increasing frequencies is not linear, showing a greater CO2elimination efficiency at higher frequencies. So, using very high frequencies on HFOV combined with volume guarantee optimizes the efficiency of gas exchange allowing to minimize lung injury.

Effect of the I/E ratio on CO2 removal during high-frequency oscillatory ventilation with volume guarantee in a neonatal animal model of RDS.

UNLABELLED: The objective of this study was to analyze the effect of I/E ratio on carbon dioxide (CO2) elimination during high-frequency oscillatory ventilation (HFOV) combined with volume guarantee (VG). Five 2-day-old piglets were studied before and after a bronchoalveolar lavage (BAL). The effect of an I/E ratio of 1:1 and 1:2 with (VG-ON) and without VG (VG-OFF) on PaCO2, as well as delta and mean airway pressures at the airway opening (∆Phf-ao, mPaw-ao) and at the tracheal level (∆Phf-t, mPaw-t) were evaluated at frequencies of 5, 8, 11, and 14 Hz. With the VG-ON, PaCO2 was significant lower with the I/E ratio of 1:2 at 5 Hz compared with the 1:1. mPaw-t was higher than mPaw-ao, with 1:1 I/E ratio, and on VG-ON, this difference was statistically significant. CONCLUSION: "In this animal study and with this ventilator, the I/E ratio of 1:1 compared to 1:2 in HFOV and VG-ON did not produce a higher CO2 lavage as when HFOV was used without the VG modality. Even more, a lower PaCO2 was found when using the lower frequency and 1:2 ratio compared to 1:1. So in contrast to non-VG HFOV mode, using a fixed tidal volume, no significant changes on CO2 elimination are observed during HFOV when the I/E ratios of 1:1 and 1:2 are compared at different frequencies." WHAT IS KNOWN: •The tidal volume on HFOV is determinant in CO 2 removal, and this is generated by delta pressure and the length of the inspiratory time. What is New: •HFOV combined with VG, an I/E ratio of 1:2 is more effective to remove CO 2 , and this is not related to the tidal volume.

Health care-associated infections in neonatology.

Health care-associated infections are common in neonatology, but there is no consensus on their definitions. This makes it difficult to compare their incidence or assess the effectiveness of prevention bundles. This is why we think it is very important to achieve a consensus on the definitions and diagnostic criteria for one of the most frequent causes of morbidity in hospitalised neonates. This document aims to standardise the definitions for the most frequent health care-associated infections, such as catheter-associated bloodstream infection, ventilator-associated pneumonia and surgical wound infection, as well as the approach to their diagnosis and treatment.

Effect of Donated Premature Milk in the Prevention of Bronchopulmonary Dysplasia.

INTRODUCTION: Breastfeeding is one of the strategies that has been shown to be effective in preventing severe forms of bronchopulmonary dysplasia (BPD). When mother's own milk (MOM) is not available, pasteurized donor milk (DM) is the best alternative. However, the evidence is inconclusive on the difference in the incidence of bronchopulmonary dysplasia (BPD) between patients fed MOM and those fed with DM. As standard DM is usually mature pooled milk donated by mothers who have delivered their babies at term, the potential benefits of preterm milk may be lost. MATERIALS AND METHODS: An observational, retrospective, single-center study was conducted in the neonatology department of a high-complexity hospital. The study included newborns <32 weeks of gestational age born between January 2020 and December 2022. When supplemental milk was needed, non-pooled preterm pasteurized donor milk (PDM) matched for gestational age and moment of lactation was used in this study, classifying preterm infants in two groups: mainly MOM (>50% of the milk) or mainly PDM (>50% of the milk). Two groups were established: those who received >50% MOM and those who received >50% PDM. They were also classified according to the diagnosis of DBP: one group included no BPD or grade 1 BPD (noBPD/1), while the other included grade 2 or 3 BPD (BPD 2-3). The objectives of this study were, firstly, to evaluate the incidence of BPD 2-3 among patients who predominantly received PDM versus MOM. Secondly, to analyze differences in the type of human milk received and its nutritional components, as well as to study the growth in patients with or without BPD. RESULTS: One hundred ninety-nine patients were included in the study. A comparison of noBPD/1 versus BPD 2-3 groups between those receiving mainly MOM versus PDM showed no significant differences (19% vs. 20%, p 0.95). PDM colostrum in BPD 2-3 compared to noBPD/1 was higher in protein content (2.24 g/100 mL (SD 0.37) vs. 2.02 g/100 mL (SD 0.29) p < 0.01), although the statistical significance decreased after adjustment for gestational age and birth weight z-score (OR 3.53 (0.86-14.51)). No differences were found in the macronutrients in the mature milk of patients feeding more than 50% PDM in both study groups. Growth of BPD 2-3 showed a greater decrease in the difference in z-scores for height at birth and at discharge compared to noBPD/1 (-1.64 vs. -0.43, p 0.03). CONCLUSIONS: The use of mainly MOM or PDM demonstrates a similar incidence of noBPD/1 or BPD 2-3. Non-pooled and matched by gestational age and time of lactation preterm donor milk can probably be an alternative when mother's own milk is not available, with a similar protective effect in the prevention of severe BPD.

Care levels in neonatal units in Spain: an updated vision for a new reality.

The Spanish Society of Neonatology established the care levels of the Neonatal Units in Spain in 2013. Since then, the birth rate in our country, as well as the universalization of knowledge, techniques and patient treatment devices, has evolved significantly. This situation forces a redefinition of the current levels of care based on quality criteria that allow better comparability between the Units and represents a challenge to improve the care of our newborns.

Lung protection strategy with high-frequency oscillatory ventilation improves respiratory outcomes at two years in preterm respiratory distress syndrome: a before and after, quality improvement study.

INTRODUCTION: Bronchopulmonary dysplasia (BPD) remains one of the major challenges of extreme prematurity. High-frequency oscillatory ventilation (HFOV) with volume guarantee (HFOV-VG) can be used as an early-rescue ventilation to protect developing lungs. However, the studies exploring the impact of this ventilatory strategy on neonatal respiratory morbidity are very limited. This study aimed at documenting the improvement in respiratory outcomes in mechanically ventilated preterm newborns, after the implementation of a new mechanical ventilation respiratory bundle. METHODS: A prospective, quality improvement study was conducted between January 2012 and December 2018 in a third level NICU in Madrid, Spain. Infants born <32 weeks of gestation with severe respiratory distress syndrome (RDS) and requiring invasive mechanical ventilation were included. The intervention consisted of a new ventilation respiratory care bundle, with HFOV as early rescue therapy using low high-frequency tidal volumes (Vthf) and higher frequencies (15-20 Hz). Criteria for HFOV start were impaired oxygenation or ventilation on conventional ventilation, or peak inspiratory pressures >15 cmH2O. Two cohorts of mechanically ventilated patients were compared, cohort 1 (2012-2013, baseline period) and cohort 2 (2016-2018, after implementation of the new bundle). Clinical outcomes at 36 weeks and 2 years of postmenstrual age were compared between the groups. RESULTS: A total of 216 patients were included, the median gestational age was 26 weeks (IQR 25-28) and median birth weight was 895 g (IQR 720-1160). There were no significant differences in survival between the groups, but patients with the protective ventilation strategy (cohort 2) had higher survival without BPD 2-3 (OR 2.93, 95%CI 1.41-6.05). At 2 years of postmenstrual age, patients in cohort 2 also had a higher survival free of baseline respiratory treatment and hospital respiratory admissions than the control group (adjusted OR 2.33, 95%CI 1.10-4.93, p=.03). The results did not suggest significant differences in neurologic development. CONCLUSIONS: In extreme premature related severe respiratory failure, the use of a lung protective HFOV-VG strategy was proven to be a useful quality improvement intervention in our unit, leading to better pulmonary outcomes at 36 weeks and additional improved respiratory prognosis at two years of age.

Recommendations for transfusion of blood products in neonatology.

The scant evidence on the use of transfusions in neonatal care explains the limitations of current clinical guidelines. Despite this, in this document we explore the most recent evidence to make recommendations for the clinical practice. The prevention of anaemia of prematurity, the use of protocols and restrictive transfusion strategies constitute the best approach for clinicians in this field. In the case of platelet transfusions, the risk of bleeding must be assessed, combining clinical and laboratory features. Lastly, fresh frozen plasma is recommended in neonates with coagulopathy and active bleeding, with congenital factor deficiencies for which there is no specific treatment or with disseminated intravascular coagulation. All blood products have adverse effects that warrant a personalised and thorough assessment of the need for transfusion.

Perinatal palliative care.

Perinatal Palliative Care is a model of care designed to prevent and treat the physical, spiritual, emotional, and social needs of fetuses and newborn infants with life-threatening or life-limiting conditions. The care extends to the infant's family. It is delivered by an interdisciplinary team to improve the quality of life from the time of diagnosis (possibly in utero) into death and bereavement (days, months or years later). To guarantee the access of this vulnerable population to high quality palliative care, structured programs and protocols need to be further developed in tertiary hospitals that treat highly complex obstetric and neonatal pathologies. Basic training is required for all the professionals involved.

Lung recruitment in neonatal high-frequency oscillatory ventilation with volume-guarantee.

BACKGROUND AND OBJECTIVES: The optimal lung volume strategy during high-frequency oscillatory ventilation (HFOV) is reached by performing recruitment maneuvers, usually guided by the response in oxygenation. In animal models, secondary spontaneous change in oscillation pressure amplitude (ΔPhf) associated with a progressive increase in mean airway pressure during HFOV combined with volume guarantee (HFOV-VG) identifies optimal lung recruitment. The aim of this study was to describe recruitment maneuvers in HFOV-VG and analyze whether changes in ΔPhf might be an early predictor for lung recruitment in newborn infants with severe respiratory failure. DESIGN AND METHODS: The prospective observational study was done in a tertiary-level neonatology department. Changes in ΔPhf were analyzed during standardized lung recruitment after initiating early rescue HFOV-VG in preterm infants with severe respiratory failure. RESULTS: Twenty-seven patients were included, with a median gestational age of 24 weeks (interquartile range [IQR]: 23-25). Recruitment maneuvers were performed, median baseline mean airway pressure (mPaw) was 11 cm H2 O (IQR: 10-13), median critical lung opening mPaw during recruitment was 14 cm H2 O (IRQ: 12-16), and median optimal mPaw was 12 cm H2 O (IQR: 10-14, p < 0.01). Recruitment maneuvers were associated with an improvement in oxygenation (FiO2 : 65.0 vs. 45.0, p < 0.01, SpO2/FiO2 ratio: 117 vs. 217, p < 0.01). ΔPhf decreased significantly after lung recruitment (mean amplitude: 23.0 vs. 16.0, p < 0.01). CONCLUSION: In preterm infants with severe respiratory failure, the lung recruitment process can be effectively guided by ΔPhf on HFOV-VG.

High-frequency Ventilation.

High-frequency ventilation (HFV) is an alternative to conventional mechanical ventilation, with theoretic benefits of less risk of ventilator lung injury and more effectivity in washout CO2. Previous clinical studies have not demonstrated advantages of HFV in preterm infants compared with conventional ventilation, so rescue HFV has been used when severe respiratory insufficiency needs aggressive ventilator settings in immature infants. Today it is possible to measure, set directly, and fix tidal volume, which can protect the immature lung from large volumes and fluctuations of the tidal volume. This strategy can be used in preterm infants with respiratory failure needing invasive ventilation.

Target volume-guarantee in high-frequency oscillatory ventilation for preterm respiratory distress syndrome: Low volumes and high frequencies lead to adequate ventilation.

BACKGROUND AND OBJECTIVES: Respiratory distress syndrome (RDS) and ventilation-induced lung injury lead to significant morbidity in preterm infants. High-frequency oscillatory ventilation with volume-guarantee (HFOV-VG) has been used as a rescue therapy and might lead to lower rates of death and bronchopulmonary dysplasia, especially when using low tidal volumes and high frequencies. The aim of the study was to define HFOV-VG parameters leading to adequate ventilation in the first 72 h of preterm RDS using a low volume and high-frequency strategy. DESIGN AND METHODS: Retrospective cohort study in a tertiary-level neonatology unit. Infants <32 weeks with severe respiratory insufficiency needing HFOV-VG were included. Patients were ventilated following a standard mechanical ventilation aiming for low tidal volumes and high frequencies. Clinical data, perinatal characteristics and high-frequency parameters corresponding with adequate ventilation were recorded. RESULTS: 116 patients were included. Median gestational age was 25 weeks (interquartile range [IQR] = 24-27), median birth weight 724 g (IQR = 600-900 g). HFOV-VG was started at 2 h, median high-frequency tidal volume was 1.63 ml/kg (IQR = 1.44-1.84) and median frequency was 16 Hz (IQR = 15-18). Weight-adjusted tidal volumes did not depend on gestational age, antenatal corticosteroids nor chorioamnionitis, and were inversely correlated with frequencies (R 2 = -0.10, p = .001). CONCLUSION: HFOV-VG can reach adequate ventilation at high frequencies when using adequate volumes, providing a feasible ventilation strategy that might be of help in preterm infants with RDS.

Sedoanalgesia in neonatal units.

Pain recognition and management continues to be a challenge for health professionals in Neonatal Intensive Care Units. Many of the patients are routinely exposed to repeated painful experiences with demonstrated short- and long-term consequences. Preterm babies are a vulnerable high-risk population. Despite international recommendations, pain remains poorly assessed and managed in many Neonatal Intensive Care Units. Due to there being no general protocol, there is significant variability as regards the guidelines for the approach and treatment of pain between the different Neonatal Intensive Care Units. The objective of this article is to review and assess the general principles of pain in the initial stages of development, its recognition through the use of standardised scales. It also includes its prevention and management with the combination of pharmacological and non-pharmacological measures, as well as to establish recommendations that help alleviate pain in daily clinical practice by optimising pain and stress control in the Neonatal Intensive Care Units.

Three-year perinatal outcomes of less invasive beractant administration in preterm infants with respiratory distress syndrome.

Objective: To assess the impact of beractant treatment using the less invasive surfactant administration (LISA) technique on perinatal outcomes in a prospective cohort of preterm infants with respiratory distress syndrome (RDS).Design: Single-center prospective study conducted in a Department of Neonatology of a tertiary care university-affiliated hospital in Madrid, Spain.Methods: Preterm infants born at <31 + 6 weeks' gestation attended in the neonatal intensive care unit (NICU) between 2012 and 2016. The main outcome was the need of invasive mechanical ventilation during the first 3 days of life. Beractant (100 mg; 4 mL/kg) was administered using the intubation-surfactant-extubation (INSURE) method during 2012 and 2013, and using the LISA procedure between 2014 and 2016.Results: The study population included 512 infants, 232 in the first period and 280 in the second period. Mechanical ventilation exposure during hospitalization showed a significant reduction in the second study period, with an adjusted OR of 0.61, 95% CI 0.39-0.96. Also, an increase of free-bronchopulmonary dysplasia (BPD) survival was found (adjusted OR 2.14, 95% CI 1.29-3.55). These significant differences in perinatal outcomes were observed only in the group of infants of 26 + 0 to 28 + 6 gestational weeks. The success rate of the first dose of beractant using LISA regarding no need of intubation during the first 3 days of life was 54% increasing to 69% in the group of 26 + 0-28 + 6 weeks of gestation. The success rate regarding free-BPD survival was 63.5% in the whole series of LISA treated patients and 72.4% in the group of 26 + 0-28 + 6 weeks. Oxygen reduction after surfactant administration (OR 39.6, 95% CI 6.1-255.8, p < .001) was predictor of LISA success, whereas LISA failure was an independent factor for air leak (OR 18.92, 95% CI 1.31-272.32, p = .031) and Death or BPD outcome (OR 19.3, 95% IC 2.5-147.4, p = .004). Gestational age was inversely associated with the need of intubation after LISA (OR 0.53, 95% CI 0.32-0.87, p = .013).Conclusions: Beractant administration by LISA technique effective reduced the need of intubation during the first 3 days of life and was associated with an increase in survival-free BPD in the group of infants born at 26 + 0 and 28 + 6 weeks' gestation.

Home births: A growing phenomenon with potential risks.

Home birth is a controversial issue that raises safety concerns for paediatricians and obstetricians. Hospital birth was the cornerstone to reduce maternal and neonatal mortality. This reduction in mortality has resulted in considering pregnancy and childbirth as a safe procedure, which, together with a greater social awareness of the need for the humanisation of these processes, have led to an increase in the demand for home birth. Studies from countries such as Australia, the Netherlands, and United Kingdom show that home birth can provide advantages to the mother and the newborn. It needs to be provided with sufficient material means, and should be attended by trained and accredited professionals, and needs to be perfectly coordinated with the hospital obstetrics and neonatology units, in order to guarantee its safety. Therefore, in our environment, there are no safety data or sufficient scientific evidence to support home births at present.

[Home births: A growing phenomenon with potential risks]. / Parto domiciliario: un fenómeno creciente con potenciales riesgos.

Home birth is a controversial issue that raises safety concerns for paediatricians and obstetricians. Hospital birth was the cornerstone to reduce maternal and neonatal mortality. This reduction in mortality has resulted in considering pregnancy and childbirth as a safe procedure, which, together with a greater social awareness of the need for the humanisation of these processes, have led to an increase in the demand for home birth. Studies from countries such as Australia, the Netherlands, and United Kingdom show that home birth can provide advantages to the mother and the newborn. It needs to be provided with sufficient material means, and should be attended by trained and accredited professionals, and needs to be perfectly coordinated with the hospital obstetrics and neonatology units, in order to guarantee its safety. Therefore, in our environment, there are no safety data or sufficient scientific evidence to support home births at present.

New indicators for optimal lung recruitment during high frequency oscillator ventilation.

Previous research has demonstrated the potential benefit derived from the combination of high frequency oscillatory ventilation and volume guarantee mode (HFOV-VG), a procedure that allows us to explore and control very low tidal volumes. We hypothesized that secondary spontaneous change in oscillation pressure amplitude (∆Phf), while increasing the mean airway pressure (MAP) using HFOV-VG can target the lung recruitment. METHODS: A two-step animal distress model study was designed; in the first-step (ex vivo model), the animal's lungs were isolated to visually check lung recruitment and, in the second one (in vivo model), they were checked through arterial oxygen partial pressure improvement. Baseline measurements were performed, ventilation was set for 10 min and followed by bronchoalveolar lavage with isotonic saline to induce depletion of surfactant and thereby achieve a low compliance lung model. The high-frequency tidal volume and frequency remained constant and the MAP was increased by 2 cmH2 O (ex vivo) and 3 cmH2 O steps (in vivo) every 2 min. Changes in ΔPhf to achieve the fixed volume were recorded at the end of each interval to describe the maximum drop point as the recruitment point. RESULTS: Fourteen Wistar Han rats were included, seven on each sub-study described. After gradual MAP increments, a progressive decrease in ΔPhf related to recruited lung regions was visually demonstrated. In the in vivo model we detected a significant comparative decrease of ΔPhf, when measured against the previous value, after reaching a MAP of 11 cmH2 O up to 17 cmH2 O, correlating with a significant improvement in oxygenation. CONCLUSION: The changes in ∆Phf, linked to a progressive increase in MAP during HFOV-VG, might identify optimal lung recruitment and could potentially be used as an additional lung recruitment marker.

Use of very low tidal volumes during high-frequency ventilation reduces ventilator lung injury.

The use of volume guarantee (VG) on high-frequency oscillatory ventilation (HFOV) allows to use fixed very low high-frequency tidal volume (VThf), maintaining adequate CO2 removal while potentially reducing the risk of ventilator-induced lung injury. OBJECTIVE: To demonstrate that the use of very low VThf can be protective compared with standard VThf on HFOV combined with VG in a neonatal animal model. STUDY DESIGN: Experimental study in 2-day-old piglets with induced respiratory distress syndrome ventilated with two different HFOV strategies combined with VG (10 Hz with high VThf versus 20 Hz with very low VThf at similar PaCO2). After 12 h of mechanical ventilation, the pulmonary histologic pattern was analyzed. RESULTS: We found in the 10 Hz group with the higher VThf compared with the 20 Hz and very low VThf group more evident and more severe histological lesions with inflammatory infiltrate within the alveolar wall and alveolar space, as well as large areas of parenchyma consolidation and areas of alveolar hemorrhage in the more severe cases. CONCLUSION: The use of very low VThf compared with higher VThf at similar CO2 removal reduces lung injury in a neonatal animal model of lung injury after prolonged mechanical ventilation with HFOV combined with VG.

Less invasive beractant administration in preterm infants: a pilot study.

OBJECTIVES: The aims of this study were to assess the efficacy and feasibility of a new, less invasive surfactant administration technique for beractant replacement using a specifically designed cannula in preterm infants born at <32 weeks of gestation and to compare short- and long-term outcomes between this approach and standard treatment, consisting of intubation, administration of surfactant and early extubation to nasal continuous positive airway pressure. METHOD: This was a single-center, prospective, open-label, non-randomized, controlled pilot study with an experimental cohort of 30 patients treated with less invasive surfactant administration and a retrospective control group comprising the 30 patients most recently treated with the standard approach. Beractant (4 ml/kg) was administered as an exogenous surfactant in both groups if patients on nasal continuous positive airway pressure during the first three days of life were in need of more than 30% FiO2. Clinicaltrials.gov: NCT02611284. RESULTS: In the group with less invasive surfactant administration, beractant was successfully administered in all patients. Thirteen patients (43.3%) in the group with less invasive surfactant administration required invasive mechanical ventilation for more than 1 hour during the first 3 days of life, compared with 22 (73%) in the control group (p<0.036). The rate of requiring invasive mechanical ventilation for more than 48 hours was similar between the infants in the two groups (46% vs. 40%, respectively). There were no differences in other outcomes. CONCLUSION: The administration of beractant (4 ml/kg) using a less invasive surfactant administration technique with a specifically designed cannula for administration is feasible. Moreover, early invasive mechanical ventilation exposure is significantly reduced by this method compared with the strategy involving intubation, surfactant administration and early extubation.