Effect of Nitric Oxide Delivery Device on Tidal Volume Accuracy During Mechanical Ventilation at Small Tidal Volumes.

Background: Inhaled nitric oxide (INO) is used in infants as a therapy for elevated pulmonary vascular resistance. When INO is delivered at low tidal volumes, displayed inspiratory and expiratory volumes vary widely. We hypothesize that volume is removed by the sampling line during the ventilation cycle, and this results in a net volume loss at low tidal volumes.

Comparison of Work of Breathing Between Noninvasive Ventilation and Neurally Adjusted Ventilatory Assist in a Healthy and a Lung-Injured Piglet Model.

Background: Noninvasive ventilation (NIV) is commonly used in neonates. A mode of NIV called neurally adjusted ventilatory assist (NAVA) offers patient-ventilator interactions by using electrical activity of the diaphragm to control mechanical breaths. We hypothesized that the work of breathing (WOB) would decrease with NIV-NAVA.

Effect of ventilator mode on patient-ventilator synchrony and work of breathing in neonatal pigs.

Background: Patient-ventilator asynchrony can result in increased work of breathing (WOB) and need for increased sedation, as well as respiratory muscle fatigue and prolonged mechanical ventilation. Different ventilator modes may result in varying degrees of asynchrony and WOB.

Objective: The objectives of this study were to assess the incidence of asynchrony and the effect of asynchrony on WOB in three modes of ventilation: pressure regulated volume control (PRVC), synchronized intermittent mandatory ventilation/volume control plus pressure support (SIMV/VC plus PS), and SIMV/PRVC plus PS.

Reliability of Displayed Tidal Volume in Healthy and Surfactant-Depleted Piglets.

Background: Volutrauma has been established as the key factor in ventilator-induced lung injury and can only be avoided if tidal volume (V) is accurately displayed and delivered. The purpose of this study was to investigate the accuracy of displayed exhaled V in a ventilator commonly used in small infants with or without a proximal flow sensor and using 3 methods to achieve a target V in both a healthy and lung-injured neonatal pig model.

Methods: This was a prospective animal study utilizing 8 male pigs, approximately 2.

Application of mid-frequency ventilation in an animal model of lung injury: a pilot study.

Background: Mid-frequency ventilation (MFV) is a mode of pressure control ventilation based on an optimal targeting scheme that maximizes alveolar ventilation and minimizes tidal volume (VT). This study was designed to compare the effects of conventional mechanical ventilation using a lung-protective strategy with MFV in a porcine model of lung injury. Our hypothesis was that MFV can maximize ventilation at higher frequencies without adverse consequences.

Validation of the accuracy of a transport ventilator utilizing a pediatric animal model.

Objective: The objective of this study was to evaluate 2 transport ventilators utilizing both a test lung and a pediatric animal model.

Methods: Two transport ventilators were utilized for evaluations. A test lung or intubated, sedated pigs (n = 9) with healthy and injured lungs were ventilated using control and support modes.

Validation of volume delivery with the use of heliox in mechanical ventilation.

Using a mixture of helium and oxygen (heliox) while mechanically ventilating patients to relieve lower airway obstruction is commonly practiced in intensive care units. The use of heliox with commercially available mechanical ventilators is usually accomplished by connecting the heliox mixture to the air inlet of the ventilator. Since most ventilators do not compensate for the difference in gas densities, particular attention to the delivered tidal volume (V ) is required.

Accuracy of small tidal volume measurement comparing two ventilator airway sensors.

Goals of modern mechanical ventilation in infants focus on preventing over-distention by limiting tidal volume. Accurate measurement of these volumes is essential. We hypothesized that tidal volume accuracy differs dependent upon the type of airway sensor utilized in tidal volumes less than 10 mL.

Accuracy of displayed volume with three airway sensors in an animal model.

Optimal mechanical ventilation in infants and pediatrics depends on the reliability of flow sensors to correctly measure flow and integrate it into accurately displayed tidal volumes (V ). However, reliability of these devices has not been established. We hypothesize that reliability would be affected by both the type of flow sensors and ventilator controllers utilized.

Neurally triggered breaths have reduced response time, work of breathing, and asynchrony compared with pneumatically triggered breaths in a recovering animal model of lung injury.

Objective: Our objective was to compare response time, pressure time product as a reflection of work of breathing, and incidence and type of asynchrony in neurally vs. pneumatically triggered breaths in a spontaneously breathing animal model with resolving lung injury.

Design: Prospective animal study.

Neurally triggered breaths reduce trigger delay and improve ventilator response times in ventilated infants with bronchiolitis.

Purpose: Neurally adjusted ventilatory assist (NAVA) is a mode of ventilation designed to improve patient-ventilator interaction by interpreting a neural signal from the diaphragm to trigger a supported breath. We hypothesized that neurally triggered breaths would reduce trigger delay, ventilator response times, and work of breathing in pediatric patients with bronchiolitis.

Methods: Subjects with a clinical diagnosis of bronchiolitis were studied in volume support (pneumatic trigger) and NAVA (pneumatic and neural trigger) in a crossover design.

Reliability of displayed tidal volume in infants and children during dual-controlled ventilation.

Objective: Previous studies have shown a significant difference between ventilator-measured tidal volume and actual-delivered tidal volume. However, these studies used external methods for measurement of compression volume. Our objective was to determine whether tidal volume could be accurately measured at the expiratory valve of a conventional ventilator using internal computer software to compensate for circuit compliance with a dual control mode of ventilation.

WITHDRAWN: Reliability of displayed tidal volume in infants and children during dual controlled ventilation.

Ahead of Print article withdrawn by publisher: OBJECTIVE:: Previous studies have shown significant difference between ventilator-measured tidal volume and actual-delivered tidal volume. However, these studies utilized external methods for measurement of compression volume. Our objective was to determine whether tidal volume could be accurately measured at the expiratory valve of a conventional ventilator using internal computer software to compensate for circuit compliance, with a dual control mode of ventilation.

Repeated measurements of respiratory mechanics in developing rats utilizing a forced oscillation technique.

The ability to successfully intubate the trachea of rats repeatedly over time, recover them, and perform repeated measures of changes in respiratory mechanics is important. The authors performed experiments utilizing 2 groups of rats at various ages in their development. Rats in the single-measurement group were studied at 1 age only.

Reliability of measured tidal volume in mechanically ventilated young pigs with normal lungs.

Objective: This study examined whether volumes can be accurately measured at the expiratory valve of a conventional ventilator using pressure support ventilation and positive end expiratory pressure with software compensation for circuit compliance available in the Servo iota ventilator.

Design And Setting: Comparison of two methods for measuring tidal volume in an animal laboratory.

Subjects: Twenty healthy, intubated, sedated, spontaneously breathing pigs.

Validation of a noninvasive blood pressure monitoring device in normotensive and hypertensive pediatric intensive care patients.

Objective: To evaluate the performance and to define limitations of a noninvasive blood pressure monitoring device in the critically ill pediatric population.

Method: Patients were included in the study if they were admitted to the Pediatric Intensive Care Unit, were between the ages of 1 month and 18 years with wrist circumferences of > or =10 cm, and had an indwelling arterial line. Patients were excluded if their systolic blood pressure differed by > or =7.