Vincent Rigo

Secretory phospholipase A2 pathway in various types of lung injury in neonates and infants: a multicentre translational study

BackgroundSecretory phospholipase A2 (sPLA2) is a group of enzymes involved in lung tissue inflammation and surfactant catabolism. sPLA2 plays a role in adults affected by acute lung injury and seems a promising therapeutic target. Preliminary data allow foreseeing the importance of such enzyme in some critical respiratory diseases in neonates and infants, as well. Our study aim is to clarify the role of sPLA2 and its modulators in the pathogenesis and clinical severity of hyaline membrane disease, infection related respiratory failure, meconium aspiration syndrome and acute respiratory distress syndrome. sPLA2 genes will also be sequenced and possible genetic involvement will be analysed.Methods/DesignMulticentre, international, translational study, including several paediatric and neonatal intensive care units and one coordinating laboratory. Babies affected by the above mentioned conditions will be enrolled: broncho-alveolar lavage fluid, serum and whole blood will be obtained at definite time-points during the disease course. Several clinical, respiratory and outcome data will be recorded. Laboratory researchers who perform the bench part of the study will be blinded to the clinical data.DiscussionThis study, thanks to its multicenter design, will clarify the role(s) of sPLA2 and its pathway in these diseases: sPLA2 might be the crossroad between inflammation and surfactant dysfunction. This may represent a crucial target for new anti-inflammatory therapies but also a novel approach to protect surfactant or spare it, improving alveolar stability, lung mechanics and gas exchange.

Newborns Need Another Tune: “I Will Survive” Sets Neonatal Resuscitation Rhythm

We read with interest D. Matlock’s abstract 1 testing The Bee Gees song “Stayin’ Alive” to set the pace of adult CPR . Since 2005, recommendations for performing CPR in infants, children and adults have been standardized, in part to ease memorization of the 100 beat per minute (bpm) chest compressions rate . However, advanced neonatal resuscitation is conducted at a rhythm of 120 events per minute, with 30 insufflations and 90 chest compressions . Providers of this procedure will not be helped by The Bee Gees. Disco music still offers songs with a tempo closer to 120 bpm. Gloria Gaynor’s “I Will Survive” (Polydor Records, 1978), at 117 bpm, could set the pace for the neonatal resuscitation team.

Automated respiratory cycles selection is highly specific and improves respiratory mechanics analysis.

Objective: Selected optimal respiratory cycles should allow calculation of respiratory mechanic parameters focusing on patient–ventilator interaction. New computer software automatically selecting optimal breaths and respiratory mechanics derived from those cycles are evaluated. Design: Retrospective study. Setting: University level III neonatal intensive care unit. Subjects: Ten mins synchronized intermittent mandatory ventilation and assist/control ventilation recordings from ten newborns. Intervention: The ventilator provided respiratory mechanic data (ventilator respiratory cycles) every 10 secs. Pressure, flow, and volume waves and pressure-volume, pressure-flow, and volume-flow loops were reconstructed from continuous pressure-volume recordings. Visual assessment determined assisted leak-free optimal respiratory cycles (selected respiratory cycles). New software graded the quality of cycles (automated respiratory cycles). Respiratory mechanic values were derived from both sets of optimal cycles. We evaluated quality selection and compared mean values and their variability according to ventilatory mode and respiratory mechanic provenance. To assess discriminating power, all 45 “t” values obtained from interpatient comparisons were compared for each respiratory mechanic parameter. Measurements and Main Results: A total of 11,724 breaths are evaluated. Automated respiratory cycle/selected respiratory cycle selections agreement is high: 88% of maximal &kgr; with linear weighting. Specificity and positive predictive values are 0.98 and 0.96, respectively. Averaged values are similar between automated respiratory cycle and ventilator respiratory cycle. C20/C alone is markedly decreased in automated respiratory cycle (1.27 ± 0.37 vs. 1.81 ± 0.67). Tidal volume apparent similarity disappears in assist/control: automated respiratory cycle tidal volume (4.8 ± 1.0 mL/kg) is significantly lower than for ventilator respiratory cycle (5.6 ±1.8 mL/kg). Coefficients of variation decrease for all automated respiratory cycle parameters in all infants. “t” values from ventilator respiratory cycle data are two to three times higher than ventilator respiratory cycles. Conclusions: Automated selection is highly specific. Automated respiratory cycle reflects most the interaction of both ventilator and patient. Improving discriminating power of ventilator monitoring will likely help in assessing disease status and following trends. Averaged parameters derived from automated respiratory cycles are more precise and could be displayed by ventilators to improve real-time fine tuning of ventilator settings.

Rigid catheters reduced duration of less invasive surfactant therapy procedures in manikins.

Different catheters can be used for less invasive surfactant therapy (LIST): feeding tubes inserted with or without Magill forceps, different angiocatheters and centre specific devices, such as umbilical catheters affixed to a stylet. This study compared the effectiveness of LIST devices and endotracheal tubes (ETT).

Distances from vocal cords to mid-trachea for optimizing endotracheal tubes depth markers according to gestational age.

Adequate endotracheal tube positioning in preterm infants is complicated by the short length of the airway. Distal markers were designed to help with the insertion of endotracheal tubes at an appropriate depth below the vocal cords. However, those markers are not standardized between manufacturers, each tube size displays only one (sometimes 2) markers to provide information for infants of various gestational ages, and indicated distances are often too long for extremely preterm infants.

Five-country manikin study found that neonatologists preferred using the LISAcath rather than the Angiocath for less invasive surfactant administration.

Less invasive surfactant administration (LISA) has been shown to decrease the risk of death and bronchopulmonary dysplasia in preterm neonates. The LISAcath is the first catheter to be specifically developed for LISA, and we compared the clinical impressions of neonatologists using the LISAcath and the commonly used Angiocath in a simulated setting.

Mathematical bias in assessment of placental residual blood volume

We read with interest the randomized controlled trial by Mercer et al. Their study adds valuable information to the debated question of the ideal timing to clamp the cord for term infants. However, in their description of early outcomes, we consider that the formula used to evaluate the relative placental residual blood volume (rPRBV) is prone to ‘mathematical’ bias: as delayed cord clamping allows blood to be transfused from the placenta to the baby, the birth weight (BW) is increased by the intervention, as found in their report and previous studies. Therefore, using an intervention dependant-BW as a denominator to compute rPRBV (rPRBV= PRBV/BW) will amplify differences between immediate and delayed cord clamping groups. The sum of BW and absolute PRBV would not be affected by the timing of cord clamping; this sum could then be used as the fraction’s denominator (rPRBV = PRBV/(PRBV+BW)) to allow a more robust estimation of rPRBV difference. CONFLICT OF INTEREST

Devices for less invasive surfactant therapy: a manikin study

Developmental problems in extremely preterm children with borderline intellectual functioning and free from neurosensory disabilities at 6.5 years in Sweden (the EXPRESS study)THE EXPRESS/CHARM STUDY : 6.5 YEAR OLD CHILDREN BORN EXTREMELY PRETERM ARE LESS PHYSICALLY ACTIVE THAN TERM PEERSEarly-life hyperglycemia in extremely preterm infants affects neurodevelopment at 6 years of age

The Effect of Positive End Expiratory Pressure (PEEP) on the Pulmonary to Systemic Blood Flow Ratio (QP/QS) in Neonates with Hypoplastic Left Heart Syndrome (HLHS)

DESIGN/METHODS: Neonates with HLHS and arterial saturation >85% were randomized in a cross-over design to low (4-0 cm H20) or high (8-14 cm H20) PEEP to achieve sat 75 85% and maintaining same tidal volume. Vessel diameter and flow velocity integral in the main pulmonary artery (QMPA) and ductus arteriosus (QPDA) were obtained using 2D Echo before and 1 hour after PEEP changes. Doppler flow velocity were performed in Celiac (CA), superior mesenteric (SMA) and anterior cerebral arteries (ACA). Other data collected inotropic score (INS), lactate (L), urine output (UO), systolic BP (SBP) and gases. Calculation: QP = QMPA QPDA, QPDA = QS. Average velocity (AV) was calculated in CA, SMA, ACA. All measurements were recorded and later analyzed blindly by an independent investigator.