Volume guarantee pressure support ventilation in extremely preterm infants and neurodevelopmental outcome at 18 months

Comparison of ventilation techniques for compensation of mask leakage using a ventilator and a regular full-face mask: A bench study

Background

The use of noninvasive ventilation (NIV) during and after extubation is common. We designed this study to determine the optimal strategy to compensate for mask leaks and achieve effective ventilation during NIV by comparing commonly used operating room ventilator systems and a regular facemask.

Methods

We tested four operating room ventilator systems (Dägger Zeus, Dägger Apollo, Dägger Fabius Tiro, and General Electric Healthcare Carestation 650) on a lung model with normal compliance and airway resistance and evaluated pressure control ventilation (PCV), volume control ventilation (VCV), and AutoFlow mode (VAF). We set the O2 flow at 10 L/min and the maximal flow at 13, 16, or 26 L/min. We simulated five leak levels, from no leak to over 40 L/min (I to V levels), using customized T-pieces placed between the lung model and the breathing circuit. We recorded the expired tidal volume (Vte) from the lung model and peak inspiratory pressure via two flow/pressure sensors that were placed distally and proximally to the T-pieces.

Results

1. Comparison of four ventilators: with any given ventilation mode, an increase in leak level caused a decrease in Vte. With PCV, only Zeus produced Vte larger than 150 ml at leak level V. 2. Effect of ventilation mode on Vte: across all four ventilators, PCV resulted in a higher Vte than VCV and VAF (P < 0.01). PCV mode with all ventilators at leak level II provided Vte values that were equal to or greater than those obtained with no leak. 3. Effect of O2 flow on Vte Using PCV mode: only Carestation 650 Vte at leak level II during PCV were significantly greater with 16 L/min O2 flow compared with 10 L/min O2 flow (P < 0.01). 4. Actual leak: increasing the O2 flow from 10 L/min to the maximum O2 flow dramatically increased the real leak with all 4 ventilators at any fixed leak level (P < 0.01). 5. Preset PIP vs. actual PIP with PCV: at low preset PIP and leak levels such as leak II and III, the discrepancy between preset PIP and actual PIP was small. The disparity between the preset and actual PIP grew when the target PIP and the leak level were raised.

Conclusion

For NIV using a mask, the ventilator is preferred whose Pressure generator is Turbine, the PCV mode is preferred in the ventilation mode and the oxygen flow is set to 10 L/min or maximum oxygen flow.

Volume-targeted ventilation vs pressure-controlled ventilation for very low birthweight infants: a protocol of a randomized controlled trial

BACKGROUND

Mechanical ventilation (MV) is essential in the management of critically ill neonates, especially preterm infants. However, inappropriate or prolonged use of invasive MV may result in ventilator-associated lung injury. A systemic review comparing pressure control ventilation (PCV) with volume-targeted ventilation mode (VTV) approved that VTV reduces the incidence of death or bronchopulmonary dysplasia (BPD) in neonates; however, this study did not analyze subgroups of very low birthweight (VLBW) infants. Therefore, the aim of this study was to compare the use of VTV and PCV in VLBW infants and to provide clinical evidence for reducing mortality and complications of MV in VLBW infants.

METHOD

A single-center randomized controlled trial will be performed. All eligible infants will be randomized and assigned to either VTV or PCV group with 1:1 ratio using sealed envelopes. Death or BPD at 36 weeks' postmenstrual age will be used as the primary outcome. Secondary outcomes include BPD, death, length of invasive MV, noninvasive mechanical ventilation, and oxygen use, length of hospital stay, failure of conventional MV, rate of using high-frequency oscillatory ventilation (HFOV) as rescue therapy, rate of reintubation within 48 h, and hospital expenses.

DISCUSSION

Systemic review suggested that VTV decreases the incidence of death or BPD in neonates compared to PLV; however, this study did not specifically analyze subgroups of VLBW infants. We designed this single-center randomized controlled trials (RCT) to add a significant contribution regarding the benefits of VTV for VLBW patients.

Ventilator Management in Extremely Preterm Infants

Advances in ventilation strategies for infants in the NICU have led to increased survival of extremely preterm infants. More than 75% of infants born at less than or equal to 27 weeks' gestation require initial mechanical ventilation for survival due to developmental immaturity of their lungs and respiratory drive. Various ventilators using different technologies and involving multiple management strategies are available for use in this population. Centers across the world have successfully used conventional, high-frequency oscillatory and high-frequency jet ventilation to manage respiratory failure in extremely preterm infants. This review explores the existing evidence for each mode of ventilation and the importance of individualizing ventilator management strategies when caring for extremely preterm infants.

Effect of high-frequency oscillatory ventilation combined with volume guarantee on preterm infants with hypoxic respiratory failure

BACKGROUND

The aim of this study was to assess the effect of volume guarantee (VG) on high-frequency oscillatory ventilation (HFOV) compared with HFOV alone in preterm infants with hypoxic respiratory failure (HRF).

METHODS

Fifty-two preterm infants with HRF refractory to conventional mechanical ventilation (CMV) were enrolled in this study. Between June 2012 and February 2016, HFOV alone was used as rescue therapy when CMV failed for 34 infants, whereas HFOV combined with VG was used as rescue therapy for the other 18 infants between March 2016 and December 2017.

RESULTS

HFOV combined with VG resulted in a reduction in the combined outcome of death or bronchopulmonary dysplasia (BPD) (p = 0.017) and also a reduction in episodes of hypercarbia (p = 0.010) compared with HFOV alone.

CONCLUSION

In this study, the preterm infants with HRF ventilated using HFOV combined with VG had a reduced combined outcome of death or BPD and hypercarbia compared with those who received HFOV alone.

Volume-targeted versus pressure-limited ventilation in neonates

BACKGROUND

Damage caused by lung overdistension (volutrauma) has been implicated in the development of bronchopulmonary dysplasia (BPD). Modern neonatal ventilation modes can target a set tidal volume as an alternative to traditional pressure-limited ventilation (PLV) using a fixed inflation pressure. Volume-targeted ventilation (VTV) aims to produce a more stable tidal volume in order to reduce lung damage and stabilise the partial pressure of carbon dioxide (pCO2).

OBJECTIVES

To determine whether VTV compared with PLV leads to reduced rates of death and death or BPD in newborn infants and to determine whether use of VTV affected outcomes including air leak, cranial ultrasound findings and neurodevelopment.

SEARCH METHODS

We used the standard search strategy of Cochrane Neonatal to search the Cochrane Central Register of Controlled Trials (CENTRAL 2016, Issue 12), MEDLINE via PubMed (1966 to 13 January 2017), Embase (1980 to 13 January 2017) and CINAHL (1982 to 13 January 2017). We also searched clinical trials databases, conference proceedings and the reference lists of retrieved articles for randomised controlled trials and quasi-randomised trials. We contacted the principal investigators of studies to obtain supplementary information.

SELECTION CRITERIA

Randomised and quasi-randomised trials comparing VTV versus PLV in infants of less than 44 weeks' postmenstrual age and reporting clinically relevant outcomes.

DATA COLLECTION AND ANALYSIS

We assessed risk of bias for each trial using Cochrane methodology. We evaluated quality of evidence for each outcome using GRADE criteria. We tabulated mortality, rates of BPD, short-term clinical outcomes and long-term developmental outcomes.

STATISTICS

for categorical outcomes, we calculated typical estimates for risk ratios (RR), risk differences (RD) and number needed to treat for an additional beneficial outcome (NNTB). For continuous variables, we calculated typical estimates for mean differences (MD). We used 95% confidence intervals (CI) and assumed a fixed-effect model for meta-analysis.

MAIN RESULTS

Twenty randomised trials met our inclusion criteria; 16 parallel trials (977 infants) and four cross-over trials (88 infants). No studies were blinded and the quality of evidence for outcomes assessed varied from moderate to low.We found no difference in the primary outcome, death before hospital discharge, between VTV modes versus PLV modes (typical RR 0.75, 95% CI 0.53 to 1.07; low quality evidence). However, there was moderate quality evidence that the use of VTV modes resulted in a reduction in the primary outcome, death or BPD at 36 weeks' gestation (typical RR 0.73, 95% CI 0.59 to 0.89; typical NNTB 8, 95% CI 5 to 20) and the following secondary outcomes: rates of pneumothorax (typical RR 0.52, 95% CI 0.31 to 0.87; typical NNTB 20, 95% CI 11 to 100), mean days of mechanical ventilation (MD -1.35 days, 95% CI -1.83 to -0.86), rates of hypocarbia (typical RR 0.49, 95% CI 0.33 to 0.72; typical NNTB 3, 95% CI 2 to 5), rates of grade 3 or 4 intraventricular haemorrhage (typical RR 0.53, 95% CI 0.37 to 0.77; typical NNTB 11, 95% CI 7 to 25) and the combined outcome of periventricular leukomalacia with or without grade 3 or 4 intraventricular haemorrhage (typical RR 0.47, 95% CI 0.27 to 0.80; typical NNTB 11, 95% CI 7 to 33). VTV modes were not associated with any increased adverse outcomes.

AUTHORS' CONCLUSIONS

Infants ventilated using VTV modes had reduced rates of death or BPD, pneumothoraces, hypocarbia, severe cranial ultrasound pathologies and duration of ventilation compared with infants ventilated using PLV modes. Further studies are needed to identify whether VTV modes improve neurodevelopmental outcomes and to compare and refine VTV strategies.

Lung-protective ventilatory strategies in intubated preterm neonates with RDS

This article provides a narrative review of lung-protective ventilatory strategies (LPVS) in intubated preterm infants with RDS. A description of strategies is followed by results on short-and long-term respiratory and neurodevelopmental outcomes. Strategies will include patient-triggered or synchronized ventilation, volume targeted ventilation, the technique of intubation, surfactant administration and rapid extubation to NCPAP (INSURE), the open lung concept, strategies of high-frequency ventilation, and permissive hypercapnia. Based on this review single recommendations on optimal LPVS cannot be made. Combinations of several strategies, individually applied, most probably minimize or avoid potential serious respiratory and cerebral complications like bronchopulmonary dysplasia and cerebral palsy.

[Efficacy of volume-targeted ventilation for the treatment of neonatal respiratory distress syndrome]

OBJECTIVE

To investigate the efficacy of volume-targeted ventilation (VTV) for the treatment of neonatal respiratory distress syndrome (NRDS).

METHODS

Fifty-two neonates with NRDS between August 2013 and August 2015 were randomly divided into two groups: VTV and pressure-controlled ventilation (PCV) (n=26 each ). A/C+Vc+ ventilation model was applied in the VTV group, and A/C+PCV ventilation model was applied in the PCV group. Arterial blood gas analysis was performed at 6, 24, and 48 hours after ventilation. The following parameters were observed: time of invasive ventilation, duration of oxygen therapy, mortality, and the incidence rates of hypocapnia, pneumothorax, ventilator-associated pneumonia (VAP), grade III-IV periventricular-intraventricular hemorrhage (PVH-IVH), periventricular leukomalacia (PVL), bronchopulmonary dysplasia (BPD), and retinopathy of prematurity (ROP).

RESULTS

Compared with the PCV group, the VTV group had a significantly shorter time of invasive ventilation (P<0.05) and significantly lower incidence rates of hypocapnia, VAP, and PVL (P<0.05); however, there were no significant differences in the duration of oxygen therapy, mortality, and incidence rates of pneumothorax, grade III-IV PVH-IVH, BPD, and ROP.

CONCLUSIONS

VTV has a better efficacy than PCV in the treatment of NRDS, and is worthy of clinical promotion and application.