Longitudinal assessment of the lung mechanics of very low birth weight preterm infants with and without bronchopulmonary dysplasia

How to ventilate preterm infants with lung compliance close to circuit compliance: real-time simulations on an infant hybrid respiratory simulator

Circuit compliance close to lung compliance can create serious problems in effective and safe mechanical ventilation of preterm infants. We considered what ventilation technique is the most beneficial in this case. A hybrid (numerical-physical) simulator of infant respiratory system mechanics, the Bennett Ventilator and NICO apparatus were used to simulate pressure-controlled ventilation (PC) and volume-controlled ventilation with constant flow (VCV_CF) and descending flow (VCV_DF), under permissive hypercapnia (PHC) (6 ml kg^-1) and normocapnia (SV) (8 ml kg^-1) conditions. Respiratory rate (RR) was 36 or 48 min^-1 and PEEP was 0.3 or 0.6 kPa. Peak inspiratory pressure (PIP), mean airway pressure (MAP), and work of breathing by the ventilator (WOB) were lower (P < 0.01, 1 - β = 0.9) using the PHC strategy compared to the SV strategy. The WOB increased (P < 0.01; 1 - β = 0.9) when the RR increased. The PC, VCV_CF, and VCV_DF modes did not differ in minute ventilation produced by the ventilator (MV_V), but the PC mode delivered the highest minute ventilation to the patient (MV_T) (P < 0.01; 1 - β = 0.9) at the same PIP, MAP, and WOB. The most beneficial ventilation technique appeared to be PC ventilation with the PHC strategy, with lower RR (36 min^-1). Graphical abstract The effectiveness of an infant ventilation depending on circuit compliance to lung compliance ratio (C_v C_L ^-1) and inspiration time (T_i). V_V, V_T, tidal volume set on the ventilator and delivered to patient, respectively.

Cognitive performance of premature infants: association between bronchopulmonary dysplasia and cognitive skills. Cross-sectional study

CONTEXT AND OBJECTIVE:

Children born prematurely often have worse cognitive performance than those born at term regarding skills such as memory, attention and processing speed. Bronchopulmonary dysplasia may compromise cognitive development. The aims here were: a) To describe the cognitive performance of preterm infants with very low birth weight; b) To investigate its association with bronchopul-monary dysplasia adjusted for sociodemographic, neonatal and post-neonatal factors.

DESIGN AND SETTING:

Cross-sectional study developed in a public tertiary-care hospital.

METHODS:

To evaluate cognition among 112 children, we applied an intelligence scale (Wechsler scale). The average scores for children with and without bronchopulmonary dysplasia were compared across the fve domains of the scale. Associations with bronchopulmonary dysplasia were investigated for domains that showed signifcant diferences between the two groups. Associations between exposure and outcome were estimated via multivariate logistic regression.

RESULTS:

There were no diferences in averages for the full-scale intelligence quotient, verbal intelligence quotient, performance intelligence quotient and general language composite domains. The processing speed quotient was the only domain that presented a signifcant diference between the two groups (P = 0.02). Among the children with bronchopulmonary dysplasia, low full-scale intelligence quotient was observed in 28.1%. In the multivariate analysis, bronchopulmonary dysplasia (odds ratio: 3.1; 95conf-dence interval: 1.1-8.7) remained associated with the outcome of processing speed quotient.

CONCLUSION:

Bronchopulmonary dysplasia was an independent risk factor for alteration of the processing speed quotient.

[Effect of caffeine citrate on early pulmonary function in preterm infants with apnea]

OBJECTIVE

To investigate the effect of caffeine citrate treatment on early pulmonary function in preterm infants with apnea.

METHODS

Forty preterm infants with apnea were randomly divided into aminophylline treatment group (20 infants) and caffeine citrate treatment group (20 infants). When the preterm infants experienced apnea after birth, they were given aminophylline or caffeine citrate in addition to assisted ventilation with continuous positive airway pressure (NCPAP). After drug discontinuation, pulmonary function was measured and compared between the two groups.

RESULTS

After treatment, compared with the aminophylline treatment group, the caffeine citrate treatment group had significantly higher tidal volume, minute ventilation volume, ratio of time to peak tidal expiratory flow to total expiratory time, ratio of volume to peak tidal expiratory flow to total expiratory volume, peak expiratory flow, and breathing flow at 75%, 50%, and 25% of tidal volume (P<0.05). The caffeine citrate treatment group had a significantly shorter time of oxygen use and NCPAP support than the aminophylline treatment group (P<0.01). Compared with the aminophylline treatment group, the caffeine citrate treatment group had a significantly lower frequency of apnea attacks (P<0.01).

CONCLUSIONS

In the treatment of apnea in preterm infants, caffeine citrate can improve early pulmonary function and reduce the incidence of apnea.