Implementation of an Inhaled Nitric Oxide Weaning Protocol and Stewardship in a Level 4 NICU to Decrease Inappropriate Use.

OBJECTIVE: Inhaled nitric oxide (iNO) is an effective but expensive treatment of pulmonary hypertension in newborns, with limited data regarding weaning. Our institution implemented a multidisciplinary iNO weaning protocol and stewardship to reduce inappropriate use of iNO. The objective of this study was to evaluate our institutional iNO usage before and after implementation. METHODS: Single-center study comparing a retrospective control group to a prospective cohort after implementation of an iNO weaning protocol. All infants in the neonatal intensive care unit (NICU) who received iNO during the study timeframe were included. The primary outcome was duration of iNO per course. RESULTS: A total of 47 courses of iNO occurred during the pre-protocol timeframe compared with 37 courses in the post-protocol timeframe. Median iNO usage per course was 149 hours (IQR, 63-243) in the pre-protocol group versus 59 hours (IQR, 37-122) in the post-protocol group (p = 0.008). Length of stay was significantly longer in the pre-protocol group (p = 0.02), likely related to significantly longer ventilator days in the pre-protocol group (p = 0.02). Compliance with initiation of weaning when recommended per the protocol was 72%, and the incidence of successful weaning was 74%. CONCLUSIONS: The implementation of an iNO weaning protocol in the NICU significantly decreased iNO usage by approximately 60% with no notable negative effects.

Preparing for an Influenza Pandemic: Hospital Acceptance Study of Filtering Facepiece Respirator Decontamination Using Ultraviolet Germicidal Irradiation.

OBJECTIVES: Predictions estimate supplies of filtering facepiece respirators (FFRs) would be limited in the event of a severe influenza pandemic. Ultraviolet decontamination and reuse (UVDR) is a potential approach to mitigate an FFR shortage. A field study sought to understand healthcare workers' perspectives and potential logistics issues related to implementation of UVDR methods for FFRs in hospitals. METHODS: Data were collected at three hospitals using a structured guide to conduct 19 individual interviews, 103 focus group interviews, and 285 individual surveys. Data were then evaluated using thematic analysis to reveal key themes. RESULTS: Data revealed noteworthy variation in FFR use across the sample, along with preferences and requirements for the use of UVDR, unit design, and FFR reuse. Based on a scale of 1 (low) to 10 (high), the mean perception of safety in a high mortality pandemic wearing no FFR was 1.25 of 10, wearing an FFR for an extended period without decontamination was 4.20 of 10, and using UVDR was 7.72 of 10. CONCLUSIONS: In addition to technical design and development, preparation and training will be essential to successful implementation of a UVDR program. Ultraviolet decontamination and reuse program design and implementation must account for actual clinical practice, compliance with regulations, and practical financial considerations to be successfully adopted so that it can mitigate potential FFR shortages in a pandemic.

Variability in expiratory flow requirements among oscillatory positive expiratory pressure.

INTRODUCTION: Oscillatory positive expiratory pressure (OPEP) devices facilitate secretion clearance by generating positive end expiratory pressure. However, different device designs may produce different levels of expiratory pressure with the same expiratory flow rate. We bench tested four devices to determine the relationship between expiratory flow and expiratory pressure in each. METHODS: A bench model was created to test the gas flow rates required by different OPEP devices to generate target expiratory pressure. Four different devices were tested: Acapella® (DH Green, Smiths Medical), AerobiKa® (Monaghan Medical Corporation), VibraPEP® (Curaplex), and vPEP™ (D R Burton Healthcare). Each OPEP device was tested to determine the expiratory flow needed to generate expiratory pressure thresholds considered appropriate for OPEP therapy. RESULTS: The expiratory flow required to generate the same expiratory pressure thresholds varied considerably among devices. Valved OPEP devices such as the VibraPEP required less flow than mechanical devices such as the vPEP, Aerobika, and Acapella. DISCUSSION: In this bench test of OPEP devices, we found considerable variability in expiratory flow requirements needed to generate an expiratory pressure of >10 cm H2O. Our finding suggests that smaller patients or those with limited expiratory airflow due to diseases such as COPD, obesity, chronic congestive heart failure, and restrictive lung disease may have better results when matched to OPEP devices requiring less expiratory airflow.

High-Flow Nasal Cannula and Aerosolized ß Agonists for Rescue Therapy in Children With Bronchiolitis: A Case Series.

Asthma and bronchiolitis are episodic obstructive pulmonary diseases characterized by bronchoconstriction, airway wall inflammation, increased mucus production, and air-flow obstruction. We present the cases of 5 infants treated for acute bronchiolitis with respiratory distress using a combination of high-flow nasal cannula oxygen (HFNC) and an Aerogen nebulizer to deliver aerosolized ß-agonist therapy. In all infants, we found that HFNC resulted in a greater heart rate increase than delivery via a facemask. We also found that patients tolerated inhaled therapy better with HFNC than a facemask.

Use of heliox delivered via high-flow nasal cannula to treat an infant with coronavirus-related respiratory infection and severe acute air-flow obstruction.

Heliox, a helium-oxygen gas mixture, has been used for many decades to treat obstructive pulmonary disease. The lower density and higher viscosity of heliox relative to nitrogen-oxygen mixtures can significantly reduce airway resistance when an anatomic upper air-flow obstruction is present and gas flow is turbulent. Clinically, heliox can decrease airway resistance in acute asthma in adults and children and in COPD. Heliox may also enhance the bronchodilating effects of ß-agonist administration for acute asthma. Respiratory syndromes caused by coronavirus infections in humans range in severity from the common cold to severe acute respiratory syndrome associated with human coronavirus OC43 and other viral strains. In infants, coronavirus infection can cause bronchitis, bronchiolitis, and pneumonia in variable combinations and can produce enough air-flow obstruction to cause respiratory failure. We describe a case of coronavirus OC43 infection in an infant with severe acute respiratory distress treated with heliox inhalation to avoid intubation.

Direct comparison of the effects of nebulized nitroprusside versus inhaled nitric oxide on pulmonary and systemic hemodynamics during hypoxia-induced pulmonary hypertension in piglets.

OBJECTIVE: To test the hypothesis that nebulized nitroprusside and inhaled nitric oxide would not differ in producing selective pulmonary vasodilation during hypoxia-induced pulmonary hypertension in piglets. SETTING: University laboratory. SUBJECTS: Five piglets. INTERVENTIONS: Piglets (n = 5) were anesthetized and instrumented to monitor systemic arterial pressure, pulmonary artery pressure, and cardiac output continuously. Hypoxia was induced (DeltaFio2 from 0.5 to 0.08), and either nebulized nitroprusside (5 mg/mL at 4 L/min flow; total dose 25 mg) or inhaled nitric oxide (20 ppm) was introduced into the ventilator circuit for 15 mins. Normoxia was then restored, and a repeat cycle of hypoxia followed by the alternate vasodilator treatment was initiated. MEASUREMENTS AND MAIN RESULTS: Hypoxia significantly reduced Pao2 (from 206 to 30 torr) and elevated pulmonary artery pressure (from 18 to 33 torr) while not significantly affecting systemic arterial pressure or cardiac output. During hypoxia, inhaled nitric oxide reduced pulmonary artery pressure from 33 to 21 torr (p <.01), whereas systemic arterial pressure and cardiac output were unchanged. During hypoxia, nebulized nitroprusside also reduced pulmonary artery pressure from 33 to 23 mm Hg (p <.01; p = nonsignificant vs. inhaled nitric oxide), whereas systemic arterial pressure and cardiac output again remained constant. The time course of the reduction in pulmonary artery pressure during inhaled nitric oxide was roughly ten-fold more rapid (<5 secs) than during nebulized nitroprusside ( approximately 1 min). Neither inhaled nitric oxide nor nebulized nitroprusside altered pH, Pao2, or Paco2. CONCLUSION: Both inhaled nitric oxide and nebulized nitroprusside produced prompt, significant, selective reduction of pulmonary artery pressure and pulmonary vascular resistance in piglets with hypoxia-induced pulmonary hypertension, without apparent effects on systemic hemodynamics or pulmonary gas exchange. The equivalence of the two effects in this animal model suggests that cautious extrapolation of the use of nebulized nitroprusside as a convenient bridge to inhaled nitric oxide in selected clinical contexts for human infants may be warranted.

Modeling the effect of progressive endotracheal tube occlusion on tidal volume in pressure-control mode.

UNLABELLED: A recognized hazard of prolonged endotracheal intubation is progressive airway occlusion resulting from deposition of secretions on the inner surface of the endotracheal tube (ETT). When volume-controlled ventilation is used, progressive ETT occlusion may be detected by monitoring the difference between peak and plateau airway pressures. In pressure-controlled modes, however, inspiratory airway pressures are preset and thus cannot act as a warning indicator. Instead, changes in delivered tidal volumes may aid the diagnosis of ETT occlusion. To determine whether tidal volume monitoring effectively detects progressive ETT occlusion, we mathematically modeled the response of a ventilator operating in pressure-controlled mode to increasing airway resistance. To corroborate our model, we then bench-tested the Siemens 300 and Puritan-Bennett 7200 ventilators by using a test lung and a series of ETTs ranging in size from 9.0 to 3.5 mm inner diameter to simulate progressive occlusion. We found that when pressure-controlled mode was used, progressive ETT occlusion did not reduce delivered tidal volumes until occlusion was nearly complete. We conclude that prolonged use of pressure-controlled mode may allow significant ETT obstruction to build up undetected, risking complete ETT occlusion and complicating the perioperative care of patients ventilated with this mode. IMPLICATIONS: Although increasing airway pressures during volume-controlled ventilation allow early recognition of endotracheal tube (ETT) obstruction, airway pressures with pressure-controlled ventilation are fixed. We found during tests of two intensive care unit ventilators that although ETT obstruction reduces delivered tidal volumes during pressure-controlled ventilation, reductions do not occur until occlusion is advanced.

Modification of a critical care ventilator for use during magnetic resonance imaging.

INTRODUCTION: The unique electromagnetic environment of the magnetic resonance imaging (MRI) scanner presents particular problems for critically ill patients requiring mechanical ventilation during MRI. Most currently available MRI-compatible ventilators are limited in scope and function and thus may not be suitable for patients requiring high peak inspiratory pressure or flow. METHODS: To determine whether a standard critical care ventilator could be used under MRI conditions, we modified a Siemens Servo 900C by replacing the standard oxygen blender with an MRI-compatible blender. We then calibrated the ventilator and tested it on a mechanical lung during active MRI scanning at magnetic fields up to 1.5 tesla. After verifying adequate function, we used the ventilator to support 21 critically ill patients requiring mechanical ventilation during MRI. RESULTS: In all cases we found no alterations in ventilator performance resulting from the electromagnetic interference typical of an MRI scan. We also found no abnormalities in the alarm systems for fraction of inspired oxygen, high inspiratory pressure, or minute volume. Finally, we found no degradation of MRI image quality resulting from ventilator operation during test scanning. CONCLUSIONS: We conclude that with minor modifications the Siemens 900C ventilator can safely ventilate critically ill patients during MRI.