Delivery of a Nebulized Aerosol to a Lung Model during Mechanical Ventilation: Effect of Ventilator Settings and Nebulizer Type, Position, and Volume of Fill

Abstract Purpose Admixture of nitric oxide (NO) to the gas inspired with mechanical ventilation can be achieved through continuous, timed, or pulsed injection of NO into the inspiratory limb. The dose and timing of NO injection govern the inspired and intrapulmonary effect site concentrations achieved with different administration modes. Here we test the effectiveness and target reliability of a new mode injecting pulsed NO boluses exclusively during early inspiration. Methods An in vitro lung model was operated under various ventilator settings. Admixture of NO through injection into the inspiratory limb was timed either (i) selectively during early inspiration (“pulsed delivery”), or as customary, (ii) during inspiratory time or (iii) the entire respiratory cycle. Set NO target concentrations of 5–40 parts per million (ppm) were tested for agreement with the yield NO concentrations measured at various sites in the inspiratory limb, to assess the effectiveness of these NO administration modes. Results Pulsed delivery produced inspiratory NO concentrations comparable with those of customary modes of NO administration. At low (450 ml) and ultra-low (230 ml) tidal volumes, pulsed delivery yielded better agreement of the set target (up to 40 ppm) and inspiratory NO concentrations as compared to customary modes. Pulsed delivery with NO injection close to the artificial lung yielded higher intrapulmonary NO concentrations than with NO injection close to the ventilator. The maximum inspiratory NO concentration observed in the trachea (68 ± 30 ppm) occurred with pulsed delivery at a set target of 40 ppm. Conclusion Pulsed early inspiratory phase NO injection is as effective as continuous or non-selective admixture of NO to inspired gas and may confer improved target reliability, especially at low, lung protective tidal volumes.

Download Full-text

Aerosol Delivery During Mechanical Ventilation: A Predictive In-Vitro Lung Model

Journal of Aerosol Medicine ◽

10.1089/jam.1992.5.251 ◽

1992 ◽

Vol 5 (4) ◽

pp. 251-259 ◽

Cited By ~ 26

Author(s):

H.D. FULLER ◽

M.B. DOLOVICH ◽

C. CHAMBERS ◽

M.T. NEWHOUSE

Keyword(s):

Mechanical Ventilation ◽

Lung Model ◽

Aerosol Delivery

Download Full-text

Emergency Pediatric Noninvasive Ventilation and Invasive Mechanical Ventilation

Pediatric Emergencies ◽

10.1093/med/9780190073879.003.0006 ◽

2020 ◽

pp. 51-63

Author(s):

Garrett S. Pacheco

Keyword(s):

Mechanical Ventilation ◽

Emergency Physician ◽

Oxygen Therapy ◽

Invasive Mechanical Ventilation ◽

Noninvasive Positive Pressure Ventilation ◽

Positive Pressure ◽

Supportive Treatment ◽

Airway Clearance Therapy ◽

Respiratory Complaints ◽

Ventilator Settings

Respiratory complaints are common conditions for children to present to emergency departments. Typically, patients respond to simple supportive treatment, whether it is airway clearance therapy, oxygen therapy, or bronchodilators. When these patients are critically ill, they often require aggressive oxygenation/ventilation with noninvasive strategies, or even tracheal intubation. The use of noninvasive positive pressure ventilation has led to a significant reduction in the necessity for endotracheal intubation in children. The emergency physician should be familiar with the indications and appropriate application of these modalities. Furthermore, when patients require invasive mechanical ventilation, the emergency physician should have an understanding of initial ventilator settings, troubleshooting alarms, and an approach to the decompensating pediatric ventilated patient.

Download Full-text

Accurate Measurement of Functional Residual Capacity and Oxygen Consumption of Patients on Mechanical Ventilation

Anaesthesia and Intensive Care ◽

10.1177/0310057x8301100212 ◽

1983 ◽

Vol 11 (2) ◽

pp. 151-157 ◽

Cited By ~ 4

Author(s):

Kevin R. Cooper ◽

Peter A. Boswell

Keyword(s):

Intensive Care Unit ◽

Mechanical Ventilation ◽

Intensive Care ◽

Oxygen Consumption ◽

Functional Residual Capacity ◽

Lung Model ◽

Capacity Measurement ◽

Icu Patients ◽

Residual Capacity

We developed an apparatus and technique for the simultaneous measurement of functional residual capacity and oxygen uptake (V̇O2) for use in intensive care unit (ICU) patients. The accuracy of the functional residual capacity measurement was proven using an in vitro lung model and the reproducibility of this measurement was established by use in ICU patients. We tested the accuracy of the V̇O2 measurement in comparison with two other methods in common use among ICU patients and our method proved accurate. We conclude that this technique for measurement of functional residual capacity and V̇O2 is highly accurate and easily applied to patients on any mode of mechanical ventilation.

Download Full-text