High Frequency Oscillatory Ventilation In Preterm Infants Research Articles

Lung Recruitment Strategies During High Frequency Oscillatory Ventilation in Preterm Lambs

Background: High frequency oscillatory ventilation (HFOV) is considered a lung protective ventilation mode in preterm infants only if lung volume is optimized. However, whilst a “high lung volume strategy” is advocated for HFOV in preterm infants this strategy is not precisely defined. It is not known to what extent lung recruitment should be pursued to provide lung protection. In this study we aimed to determine the relationship between the magnitude of lung volume optimization and its effect on gas exchange and lung injury in preterm lambs.Methods: 36 surfactant-deficient 124–127 d lambs commenced HFOV immediately following a sustained inflation at birth and were allocated to either (1) no recruitment (low lung volume; LLV), (2) medium- (MLV), or (3) high lung volume (HLV) recruitment strategy. Gas exchange and lung volume changes over time were measured. Lung injury was analyzed by post mortem pressure-volume curves, alveolar protein leakage, gene expression, and histological injury score.Results: More animals in the LLV developed a pneumothorax compared to both recruitment groups. Gas exchange was superior in both recruitment groups compared to LLV. Total lung capacity tended to be lower in the LLV group. Other parameters of lung injury were not different.Conclusions: Lung recruitment during HFOV optimizes gas exchange but has only modest effects on lung injury in a preterm animal model. In the HLV group aiming at a more extensive lung recruitment gas exchange was better without affecting lung injury.

High-Frequency Oscillatory Ventilation Versus Synchronized Intermittent Mandatory Ventilation Plus Pressure Support in Preterm Infants With Severe Respiratory Distress Syndrome

Mechanical ventilation and surfactants are the standard treatment of preterm respiratory distress syndrome (RDS). The effects of the primary ventilation model on bronchopulmonary dysplasia (BPD) and long-term neurodevelopment outcomes are controversial. The purpose of this study was to compare the efficacy and safety of high-frequency oscillatory ventilation (HFOV) and synchronized intermittent mandatory ventilation plus pressure support ventilation (SIMV-PSV) in preterm infants with severe RDS. A total of 366 eligible preterm infants were randomly assigned to treatment with HFOV (n = 184) or SIMV-PSV (n = 182). Surfactant was applied if PaO2/FIO2 was < 200 mm Hg after 2 hours of ventilation. Primary outcomes were mortality or incidence of BPD. Secondary outcomes were duration of ventilation and hospitalization, surfactant requirements, pneumothorax, retinopathy of prematurity ≥ stage 2, and neurodevelopment at 18 months of corrected age. Survival and complete outcome data were available for 288 infants at 18 months of corrected age. The incidence of death or BPD was significantly higher in the SIMV-PSV group (P = .001). The duration of mechanical ventilation and hospitalization was shorter and the incidence of surfactant requirement and retinopathy of prematurity was lower in the HFOV group (P < .001, P = .002, P = .04, respectively). Moderate or severe neurological disability was less frequent in the HFOV group than in the SIMV-PSV group at 18 months (P = .03). The combination of HFOV and surfactant dramatically reduced negative outcomes in preterm infants with severe RDS. Initial ventilation with HFOV in preterm infants with severe RDS reduces the incidence of death and BPD, and improves long-term neurodevelopment outcomes. (ClinicalTrials.gov NCT01496508).

Unexpected effect of recruitment procedure on lung volume measured by respiratory inductive plethysmography (RIP) during high frequency oscillatory ventilation (HFOV) in preterm neonates with respiratory distress syndrome (RDS)

Background: In clinical practice, one of the major problems in optimizing recruitment or lung volume during HFOV in preterm infants is the inability to accurately measure direct changes in lung volume at bedside. Objective: To evaluate changes in lung volume during the recruitment phase of elective HFOV in preterm infants with RDS using respiratory inductive plethysmography. Material and methods: The preliminary results of an observational prospective study were reported. Newborns with GA ≤ 27 weeks requiring elective HFOV for a diagnosis of RDS were studied within the first 6 hours of life using RIP technology, before surfactant instillation. HFOV was performed with Draeger Babylog 8000 plus ventilator with “optimum lung volume strategy “(continuous distending pressure (CDP) increased step-by-step until FiO2 ≤ 0.25 was reached). Data on ventilator settings, gas exchange and RIP volume were collected and analyzed. The analysis package used in this study visualizes measured data from the Bicore-II device (CareFusion), Pulse Oximeter Masimo, AX300 FiO2 monitor device and TCM4 shuttle (TCM4, Radiometer, Copenaghen, Denmark). Results: Four preterm infants (two females) with mean ± SD gestational age of 26.5 ± 1.0 weeks and mean ± SD birth weight of 978 ± 188 grams were studied. Relative FRC slightly increased during the first steps of the recruitment phase, while deeply decreased at higher CDP values (≥ 15 cm H2O). Notwithstanding FiO2 decreased until 0.25 in all the newborns except one. Conclusions: Because RIP cannot differentiate between changes in lung fluid or intrathoracic gas, we hypothesized that as CDP increases and total lung capacity is approached, pulmonary vascular resistance increases as a consequence of the compression of intra-alveolar vessels. This increases right ventricular afterload which, combined with re-establishment of right-to left shunting, results in decreased pulmonary blood flow and then decreased lung volume. Caution should then be used when using high CDP values during the recruitment procedure.

Recently published papers: of head injuries, high frequencies and haemodynamic optimization.

Recently published papers: of head injuries, high frequencies and haemodynamic optimization.

Efficacité et limites de la ventilation par oscillations à haute fréquence après échec de la ventilation conventionnelle chez des prématurés atteints de maladie des membranes hyalines sévère

Conflicting reports of high-frequency oscillatory ventilation (HFOV) use as an alternative to conventional mechanical ventilation have been published. This retrospective study has evaluated the efficacy and safety of rescue HFOV in preterm infants with severe hyaline membrane disease (HMD) after the failure of conventional mechanical ventilation (CMV). All newborns hospitalized in our neonatal intensive care unit (NICU) from 10.1.1993 to 15.4.1995 with CMV failure, defined as the need for more than 55% FiO2 without any improvement for at least six hours, have been retrospectively studied. The infants were shared according to the absence (Gr I) or the presence (Gr II) of persistent pulmonary hypertension of neonate (PPHN) in addition to HMD before HFOV. Gestational age (GA) was 29.2 +/- 3.7 weeks (mean +/- SD) in Gr I and 30.3 +/- 2.8 in Gr II. Birth weight was 1379 +/- 750 g and 1471 +/- 612 g, respectively. As soon as three hours after the onset of HFOV in both groups, a dramatic improvement was observed with a FiO2 drop from 82 +/- 20% to 64.8 +/- 25.5% (P < 0.01). Among the infants, 62% survived without any major disability and 28% died (46% in Gr II vs 12% in Gr I, P < 0.01). A trend towards a worsening of pre-existing brain lesions has been noticed. An increased risk of mortality was observed when a secondary worsening in O2 requirements occurred 24 hours after the onset of HFOV, despite an initial significant improvement. SGA was also associated with a poor prognosis (46% of the deaths vs 29% for AGA infants, P < 0.05). HFOV has been successfully used in premature infants with severe respiratory disease and failure of CMV. Criteria of poor prognosis were PPHN and SGA, or a secondary worsening in oxygen requirements after initial improvement. A trend towards aggravation of pre-existing brain lesions has been noticed after HFOV. This aggravation is more frequent when PPHN is associated with HMD. This observation suggests caution for HFOV use when these conditions are present in premature infants.