Silvia Bianchi

Volume guarantee versus high frequency ventilation: lung inflammation in preterm infants

Background: Appropriate ventilation together with improvement of clinical care of premature babies can contribute to reducing lung inflammation, known to represent the “primum movens” of bronchopulmonary dysplasia (BPD). High-frequency oscillatory ventilation (HFOV) and volume-guarantee (VG) ventilation are effective in the treatment of neonatal respiratory distress syndrome (RDS). Objective: To assess the potential of HFOV and VG to prevent BPD in the acute phase of RDS, by a randomised clinical study evaluating lung inflammation in premature infants. Study design: Forty infants (gestational age 25–32 weeks) with RDS were assigned to assist-control ventilation plus VG (Vt = 5 ml/kg) or HFOV (both with a Dräger Babylog 8000 plus ventilator). Levels of interleukin (IL) 6, IL8 and tumour necrosis factor were determined in tracheal aspirate on days 1, 3 and 7 of life. Results: In the HFOV group IL6 levels were significantly higher on day 3 (0.5 (0.2) vs assisted-control ventilation plus VG group 0.1 (0.2) ng/ml) and oxygen dependency was significantly longer (36 (23) vs assisted-control ventilation plus VG group 19 (11) days). Conclusion: VG ventilation is an effective lung-protective strategy to be used in acute RDS, inducing a lower expression of early inflammation markers than HFOV. Whether the use of this initial ventilatory strategy contributes to the prevention of BPD requires further studies.

Bronchoalveolar lavage with diluted porcine surfactant in mechanically ventilated term infants with meconium aspiration syndrome.

AbstractBackground: To evaluate the efficacy and safety of bronchoalveolar lavage (BAL) with diluted porcine surfactant in mechanically ventilated term infants with severe acute respiratory distress syndrome (ARDS) due to meconium aspiration syndrome (MAS). Methods: Eight consecutive mechanically ventilated term infants with severe ARDS due to MAS underwent BAL with 15 mL/kg of diluted (5.3mg phospholipid/mL) surfactant saline suspension (porcine surfactant [Curosurf®]). Treatment was administered slowly in aliquots of 2.5mL. The mean age of neonates at treatment was 3.5 (range 1–8) hours. Heart rate, systemic blood pressure and oxygen saturation were monitored continuously. Arterial blood gases were measured immediately before treatment, and again at 3 and 6 hours post-treatment. Chest x-rays were taken 6 and 24 hours after treatment. Results: Radiological improvement was evident in all eight patients 6 hours post-treatment. Compared with pre-BAL values, significant improvements (p < 0.05) in mean values for partial pressure of oxygen in arterial blood, partial pressure of carbon dioxide in arterial blood, pH, arterial/alveolar O2 ratio and oxygenation index were documented at 3 and 6 hours after BAL. In all patients, tracheal fluids that had been meconium-stained prior to BAL were clear of meconium after BAL. Only one patient required nitric oxide therapy for transient pulmonary hypertension. No adverse sequelae of treatment occurred during the study. Conclusions: BAL with dilute porcine surfactant administered slowly in 2.5mL aliquots improved oxygenation and chest x-ray findings, without causing major adverse effects, in mechanically ventilated term infants with ARDS due to MAS.

Alveolar recruitment in the delivery room

Most preterm babies with a gestational age less than 23–27 weeks need a respiratory support in the delivery room (DR); the aim of ventilation is to create and maintain a functional residual capacity (FRC); to facilitate gas exchange and to minimize acute lung injury. The application of a continuous positive airway pressure (CPAP) from the first breaths helps in obtaining a lung volume stabilization. Efficacy and safety of the application of a sustained lung inflation (SLI) at birth is still under careful evaluation. The prompt increase of the hearth rate and oxygen saturation in the preliminary studies at the moment available in the literature are signs of the good efficacy of the manoeuvre but the effects of the SLI on oxygenation and hemodynamics are undetermined. When preterm infants need respiratory assistance in the DR, respiratory function monitoring is desirable to apply adequate and gentle resuscitation manoeuvres. Clinical large trials taking place in the DR are needed but they are also extremely difficult to be designed and performed.

ELBW infants: to intubate or not to intubate in the delivery room?

Few years ago, elective tracheal intubation in the delivery room was considered as the routine approach in managing respiratory failure in extremely-low-birth-weight infants (ELBW), at least in terms of surfactant administration. Over recent years, the indications and principles of neonatal resuscitation of ELBW infants have been partially reviewed: many randomized clinical trials (RCT) have demonstrated that these infants do not die quickly without intubation in the delivery room, and many infants only need a little help in completing foetal-neonatal transition through the use of lung recruitment manoeuvres in the delivery room (e.g. sustained lung inflation, CPAP) and then only non-invasive ventilation support. Tracheal intubation and mechanical ventilation can be reserved solely for depressed or ELBW, although further RCTs are needed to provide additional information and to provide a conclusive response to the eternal debate as to whether intubation at birth can influence outcome for ELBW infants.

Ventilatory management of asphyxiated infant during hypothermia

Hypothermia is used for its neuroprotective effect in perinatal asphyxia. Mechanical ventilation is often used as a supportive therapy for severe asphyxiated infants who can present various degrees of respiratory failure. Animal studies demonstrated a protective effect of cooling on the lungs due to reduced ventilatory requirements. Even if actual knowledge on the effects of hypothermia and rewarming on respiratory parameters during mechanical ventilation is limited, nevertheless human studies seem to demonstrate that hypothermia is safe and does not cause significant changes in the level of respiratory supports.

Velocity time integral for right upper pulmonary vein in VLBW infants with patent ductus arteriosus

OBJECTIVE: Early diagnosis of significant patent ductus arteriosus reduces the risk of clinical worsening in very low birth weight infants. Echocardiographic patent ductus arteriosus shunt flow pattern can be used to predict significant patent ductus arteriosus. Pulmonary venous flow, expressed as vein velocity time integral, is correlated to ductus arteriosus closure. The aim of this study is to investigate the relationship between significant reductions in vein velocity time integral and non-significant patent ductus arteriosus in the first week of life. METHODS: A multicenter, prospective, observational study was conducted to evaluate very low birth weight infants (<1500 g) on respiratory support. Echocardiography was used to evaluate vein velocity time integral on days 1 and 4 of life. The relationship between vein velocity time integral and other parameters was studied. RESULTS: In total, 98 very low birth weight infants on respiratory support were studied. On day 1 of life, vein velocity time integral was similar in patients with open or closed ductus. The mean vein velocity time integral significantly reduced in the first four days of life. On the fourth day of life, there was less of a reduction in patients with patent ductus compared to those with closed patent ductus arteriosus and the difference was significant. CONCLUSIONS: A significant reduction in vein velocity time integral in the first days of life is associated with ductus closure. This parameter correlates well with other echocardiographic parameters and may aid in the diagnosis and management of patent ductus arteriosus.