Feasibility and physiological effects of noninvasive neurally adjusted ventilatory assist in preterm infants.

BackgroundNoninvasive neurally adjusted ventilator assist (NIV-NAVA) was introduced to our clinical practice via a pilot and a randomized observational study to assess its safety, feasibility, and short-term physiological effects.MethodsThe pilot protocol applied NIV-NAVA to 11 infants on nasal CPAP, high-flow nasal cannula, or nasal intermittent mandatory ventilation (NIMV), in multiple 2- to 4-h periods of NIV-NAVA for comparison. This provided the necessary data to design a randomized, controlled observational crossover study in eight additional infants to compare the physiological effects of NIV-NAVA with NIMV during 2-h steady-state conditions.

Evaluation of Ultrasound-Based Sensor to Monitor Respiratory and Nonrespiratory Movement and Timing in Infants.

Goal: To describe and validate a noncontacting sensor that used reflected ultrasound to separately monitor respiratory, nonrespiratory, and caretaker movements of infants.

Methods: An in-phase and quadrature (I & Q) detection scheme provided adequate bandwidth, in conjunction with postdetection filtering, to separate the three types of movement. The respiratory output was validated by comparing it to the electrical activity of the diaphragm (Edi) obtained from an infant ventilator in 11 infants.

Impulse oscillometry versus spirometry in a long-term study of controller therapy for pediatric asthma.

Background: Determination of the benefits and limitations of specific physiologic tests has not been well studied in long-term clinical pediatric trials.

Objective: We sought to determine the utility of impulse oscillometry in a long-term comparison of 3 controller regimens in children with persistent asthma.

Methods: Children 6 to 14 years of age with mild-to-moderate persistent asthma were characterized with oscillometry and spirometry before entry into a clinical trial and then serially during 48 weeks of therapy with either an inhaled corticosteroid, a combination inhaled corticosteroid with a long-acting beta-agonist, or a leukotriene receptor antagonist.

Virulence role of group B Streptococcus beta-hemolysin/cytolysin in a neonatal rabbit model of early-onset pulmonary infection.

We examined the virulence role of group B Streptococcus (GBS) beta-hemolysin/cytolysin (beta h/c) in a neonatal-rabbit model of GBS pulmonary infection. Rabbits infected intratracheally with wild-type (wt) GBS developed focal pneumonia and, by 18 h after infection, had 100-fold more bacteria in lung tissue than did rabbits infected with a delta beta h/c mutant. Mortality (40% vs.

Increased fragility of pulmonary capillaries in newborn rabbit.

The pulmonary capillaries of neonatal lungs are potentially vulnerable to stress failure because of the complex changes in the pulmonary circulation that occur at birth. We perfusion fixed the lungs from nine anesthetized newborn rabbits at capillary transmural pressures (P(tm)) of 5 +/- 5, 10 +/- 5, and 15 +/- 5 cmH(2)O. Normal microscopic appearances were seen at P(tm) values of 5 +/- 5 and 10 +/- 5 cmH(2)O, but massive airway edema was observed in lungs perfused at a P(tm) of 15 +/- 5 cmH(2)O.

Thickness of the blood-gas barrier in premature and 1-day-old newborn rabbit lungs.

The pulmonary capillaries of neonatal lungs are potentially vulnerable to stress failure because of the complex changes in the pulmonary circulation that occur at birth. We studied the ultrastructure of the blood-gas barrier (BGB) in premature and 1-day-old rabbit lungs and compared it with the ultrastructure of adult lungs. Normal gestation of rabbits is 30 days.