Structural and haemodynamic evaluation of less invasive surfactant administration during nasal intermittent positive pressure ventilation in surfactant-deficient newborn piglets.

The most recent approaches to the initial treatment of respiratory distress syndrome (RDS)- involve non-invasive ventilation (NIV) and less-invasive surfactant (SF) administration (LISA). Combining these techniques has been proven a useful treatment option for SF-deficient neonates. The objective of this study was to explore the impact on the brain (using cerebral near infrared spectroscopy, NIRS) of different LISA methods during NIV, using nasal intermittent positive pressure ventilation (NIPPV) for treating neonatal RDS. For this, we used five groups of spontaneously breathing newborn piglets (n = 6/group) with bronchoalveolar lavage (BAL)-induced respiratory distress which received NIPPV only (controls), poractant-alfa using the INSURE-like method (bolus delivery) followed by NIPPV, or poractant-alfa using one of three LISA devices, 1) a nasogastric tube (NT), 2) a vascular catheter (VC) or 3) the LISAcath® catheter. We assessed pulmonary, hemodynamic and cerebral effects, and performed histological analysis of lung and brain tissue. Following BALs, the piglets developed severe RDS (pH<7.2, PaCO2>70 mmHg, PaO2<70 mmHg, dynamic compliance<0.5 ml/cmH2O/kg at FiO2 = 1). Poractant-alfa administration using different LISA techniques during NIPPV was well tolerated and efficacious in newborn piglets. In our study, although all groups showed normal physiological ranges of total lung injury score and biochemical lung analysis, VC and LISAcath® catheters were associated with better values of lung compliance and lower values of lung damage than NIPPV, NT or INSURE-like methods. Moreover, neither of the SF administration methods used (LISA or INSURE-like) had a significant impact on the histological neonatal brain injury score. Of note, the LISAcath® has been recently withdrawn from the market.

Cerebral oxygenation associated with INSURE versus LISA procedures in surfactant-deficient newborn piglet RDS model.

BACKGROUND: Nasal continuous-positive airway pressure (nCPAP) with the INSURE (INtubation-SURfactant-Extubation) or LISA (Less-Invasive Surfactant Administration) procedures are increasingly being chosen as the initial treatment for neonates with surfactant deficiency. Our objective was to compare the effects on cerebral oxygenation of different methods for surfactant administration: INSURE and LISA, using a nasogastric tube (NT) or a LISAcath® catheter, in spontaneously breathing SF-deficient newborn piglets. METHODS: Eighteen newborn piglets with SF-deficient lung injury produced by repetitive bronchoalveolar lavages were randomly assigned to INSURE, LISA-NT, or LISAcath® groups. We assessed pulmonary (gas exchange, lung mechanics, lung histology) and hemodynamic (mean arterial blood pressure, heart rate) changes, cerebral oxygenation (cTOI) and cerebral fractional tissue extraction (cFTOE), with near-infrared spectroscopy, carotid blood flow and brain histology. RESULTS: SF-deficient piglets developed respiratory distress (FiO2 = 1, pH <7.2, PaCO2 >70 mmHg, PaO2 <70 mmHg, Cdyn <0.5 mL/cmH2 O/kg). Rapid improvements in pulmonary status were observed in all surfactant-treated groups without hemodynamic alterations. In the INSURE group, a transient decrease in cTOI occurred during and immediately after surfactant administration, while cTOI only decreased during surfactant administration in the LISA-NT group and did not change significantly in the LISAcath® group. Brain injury scores were low in all surfactant-treated groups. CONCLUSION: In spontaneously breathing SF-deficient newborn piglets, short-lasting decreases in cerebral oxygenation are associated with surfactant administration by the INSURE method or LISA using an NT, while no cerebral oxygenation changes occurred with LISA using a LISAcath®. Notably, none of treatments studied seems to have a negative impact on the neonatal brain.

Epidemiological surveillance using information technologies in Paraguay.

This article presents the early work on a project in Paraguay for epidemiological surveillance using information technologies. This project is a response of our university to a governmental request to establish links of cooperation and development between academic public sectors of Spain and Paraguay. The overall project objective is the promotion ofa healthy citizenry through the application of information and communication technologies to the monitoring of populations vulnerable to febrile syndromes (FS). The goal of this project is to create the infrastructure that will allow the population of the country to easily communicate with health centers and provide information on cases of FS. The telephone network will be the main physical support for this communication. The project was formally initiated in January 2009 with the implementation of the prototype system. During the first half of 2010, the pilot project will be implemented in Asunción, Paraguay.

Dynamic and quasi-static lung mechanics system for gas-assisted and liquid-assisted ventilation.

Our aim was to develop a computerized system for real-time monitoring of lung mechanics measurements during both gas and liquid ventilation. System accuracy was demonstrated by calculating regression and percent error of the following parameters compared to standard device: airway pressure difference (Delta P(aw)), respiratory frequency (f(R) ), tidal volume (V(T)), minute ventilation (V'(E)), inspiratory and expiratory maximum flows (V'(ins,max), V'(exp,max)), dynamic lung compliance (C(L,dyn) ), resistance of the respiratory system calculated by method of Mead-Whittenberger (R(rs,MW)) and by equivalence to electrical circuits (R(rs,ele)), work of breathing (W(OB)), and overdistension. Outcome measures were evaluated as function of gas exchange, cardiovascular parameters, and lung mechanics including mean airway pressure (mP(aw)). Delata P(aw), V(T), V'(ins,max), V'(exp,max), and V'(E) measurements had correlation coefficients r = 1.00, and %error < 0.5%. f(R), C(L,dyn), R(rs,MW), R(rs,ele), and W(OB) showed r > or = 0.98 and %error < 5%. Overdistension had r = 0.87 and %error < 15%. Also, resistance was accurately calculated by a new algorithm. The system was tested in rats in which lung lavage was used to induce acute respiratory failure. After lavage, both gas- and liquid-ventilated groups had increased mP(aw) and W(OB), with decreased V(T), V'(E), C(L,dyn), R(rs,MW), and R(rs,ele) compared to controls. After 1-h ventilation, both injured group had decreased V(T), V'(E) , and C(L,dyn), with increased mP(aw), R(rs,MW), R(rs,ele), and W(OB) . In lung-injured animals, liquid ventilation restored gas exchange, and cardiovascular and lung functions. Our lung mechanics system was able to closely monitor pulmonary function, including during transitions between gas and liquid phases.