Gabriel Musante

Proportional assist ventilation in low birth weight infants with acute respiratory disease: A comparison to assist/control and conventional mechanical ventilation ☆ ☆☆ ★

OBJECTIVESnTo compare the physiologic efficacy and safety aspects of proportional assist (PA), assist/control (A/C), and intermittent mandatory ventilation (IMV) in very low birth weight infants with acute respiratory illness and to test the hypothesis that ventilatory pressure requirements are lower and arterial oxygenation is improved during PA when compared with IMV or A/C at an equivalent inspired oxygen fraction.nnnSTUDY DESIGNnRandomized, 3-period, crossover design.nnnMETHODSnThirty-six infants were stratified by birth weight (600 to 750, 751 to 900, and 901 to 1200 g) and exposed to consecutive 45-minute epochs of the 3 modalities in a sequence chosen at random. Tidal volumes of 4 to 6 mL/kg were targeted during A/C and IMV. The IMV rate was matched to the rate during an A/C test period. PA was adjusted to unload the resistance of the endotracheal tube and the disease-related increase in lung elastic recoil.nnnRESULTSnCompared with A/C and IMV, PA maintained similar arterial oxygenation with lower airway and transpulmonary pressures (15% to 44% reduction depending on the index variable). The oxygenation index decreased by 28% during PA. No adverse events were observed. The number and severity of apneic episodes and periods of arterial oxygen desaturations were similar with the 3 modes. Similar results were obtained within each birth weight subgroup.nnnCONCLUSIONSnPA safely maintains gas exchange with smaller transpulmonary pressure changes compared with A/C and IMV. It may therefore offer a way of reducing the incidence of chronic lung disease in low birth weight infants.

Proportional Assist Ventilation Decreases Thoracoabdominal Asynchrony and Chest Wall Distortion in Preterm Infants

Thoracoabdominal asynchrony (TAA) and chest wall distortion (CWD) are commonly seen in preterm infants secondary to a highly compliant rib cage and poor compensation of distorting forces by inspiratory rib cage muscles. Continuous positive airway pressure (CPAP) reduces TAA and CWD by stenting the chest wall. We hypothesized that application of positive airway pressure only during inspiration and in proportion to an infants inspiratory effort should have a similar but more pronounced effect than CPAP alone. A ventilator providing airway pressure changes in proportion to flow and volume generated by an infant (proportional assist ventilation) was used to unload the respiratory pump during inspiration. Ten preterm infants were studied [birth weight, 745 (635–1175) g; gestational age, 26.5 (24–31) wk; postnatal age 3 (1–7) d; medium (range)]. TAA and CWD were determined by respiratory inductive plethysmography. TAA was expressed as the phase angle between the rib cage and abdominal motion and CWD as the total compartmental displacement ratio. In addition, we measured tidal volume with a pneumotachograph and esophageal and airway pressure deflections with pressure transducers. Measurements were obtained during alternating periods of CPAP and two different degrees of support (Gain 1 = 1.09 ± 0.68, Gain 2 = 1.84 ± 0.84 cm H2O/mL) that were provided by a proportional assist ventilator. Phase angle and the total compartmental displacement ratio decreased with increasing gain compared with CPAP alone. Peak airway pressure increased from 0.6 to 3.8 to 7.6 cm H2O above positive end-expiratory pressure (PEEP) with CPAP, Gain 1, and Gain 2, respectively, as tidal volume increased from 2.8 to 4.1 to 4.7 mL/kg. Esophageal pressure changes decreased only little with increasing gain. Chest wall excursion increased and abdominal movement decreased, indicating a redistribution of tidal volume between chest and abdomen. We conclude that proportional assist ventilation reduces TAA and CWD by generating a small increase in airway pressure that occurs in synchrony and in proportion to each inspiratory effort.

Randomized, Crossover Study of Volume Guarantee (VG) Versus Synchronized Intermittent Mandatory Ventilation (SIMV) in Very Low Birth Weight (VLBW) Infants Recovering from Respiratory Failure

Randomized, Crossover Study of Volume Guarantee (VG) Versus Synchronized Intermittent Mandatory Ventilation (SIMV) in Very Low Birth Weight (VLBW) Infants Recovering from Respiratory Failure

Computer Controlled Inspired Oxygen Concentration in Mechanically Ventilated Very Low Birthweight Infants

Computer Controlled Inspired Oxygen Concentration in Mechanically Ventilated Very Low Birthweight Infants

Respiratory Mechanical Unloading Decreases Thoraco-Abdominal Asynchrony and Chest Wall Distortion In Very Low Birth Weight Preterm Infants. |[dagger]| 1552

Respiratory Mechanical Unloading Decreases Thoraco-Abdominal Asynchrony and Chest Wall Distortion In Very Low Birth Weight Preterm Infants. † 1552

Proportional Assist Ventilation (PAV): A New Strategy for Mechanical Ventilation in Low Birth Weight Infants. |[dagger]| 1038

During PAV, the airway pressure increases in proportion to inspiratory flow and tidal volume throughout each spontaneous inspiration such that partial respiratory unloading of airway resistance and lung elastic recoil are induced. In contrast, fixed inflation pressure and timing profiles are imposed during Assist/Control (AC) and Conventional Mechanical Ventilation (CV). We compared PAV, AC, and CV in a randomized, three period crossover study.

Branched-Chain Amino Acids (BCAA) and Respiratory Center Function in the Preterm Neonate: A Prospective, Randomized, Double-Blind Trial. † 1480

Branched-Chain Amino Acids (BCAA) and Respiratory Center Function in the Preterm Neonate: A Prospective, Randomized, Double-Blind Trial. † 1480