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.

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.

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.

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.

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.

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]

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.

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.

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.

New Ventilator Strategies: High-Frequency Oscillatory Ventilation Combined with Volume Guarantee

High-frequency oscillatory ventilation (HFOV) has been proposed as an alternative method of invasive ventilation in immature infants to prevent ventilator lung injury. To better control the size of the high-frequency tidal volume and to prevent large tidal volumes, a new strategy of controlling the tidal volume during HFOV (VThf) has been developed, HFOV-volume guarantee (VG). Data from preclinical, neonatal animal studies in normal and surfactant-depleted lungs have demonstrated the feasibility of this technique to directly control the VThf in the normal compliance and low compliance situations. Different I:E ratios also can modify the effect of CO₂ washout during HFOV combined with VG in a different way as without the VG modality. Finally, clinical use of this technique in newborn infants has demonstrated the possibility of using very high frequency combined with constant very low VThf to decrease the risk of lung trauma related to the ventilator.

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

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.

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.