ABSTRACT
Inadequate gas conditioning during non-invasive ventilation (NIV) can impair the anatomy and function of nasal mucosa. The resulting symptoms may have a negative effect on patients' adherence to ventilatory treatment, especially for chronic use. Several parameters, mostly technical aspects of NIV, contribute to inefficient gas conditioning. Factors affecting airway humidity during NIV include inspiratory flow, inspiratory oxygen fraction, leaks, type of ventilator, interface used to deliver NIV, temperature and pressure of inhaled gas, and type of humidifier. The correct application of a humidification system may avoid the effects of NIV-induced drying of the airway. This brief review analyses the consequences of airway dryness in patients receiving NIV and the technical tools necessary to guarantee adequate gas conditioning during ventilatory treatment. Open questions remain about the timing of gas conditioning for acute or chronic settings, the choice and type of humidification device, the interaction between the humidifier and the underlying disease, and the effects of individual humidification systems on delivered humidity.
Subject(s)
Humidity , Nebulizers and Vaporizers , Positive-Pressure Respiration/methods , Humans , Humidity/standards , Nasal Mucosa/pathology , Nasal Mucosa/physiology , Nebulizers and Vaporizers/standards , Positive-Pressure Respiration/standards , Sleep Apnea, Obstructive/physiopathology , Sleep Apnea, Obstructive/therapyABSTRACT
OBJECTIVE: We designed a multicenter randomized trial to compare 3 approaches to the initial respiratory management of preterm neonates: prophylactic surfactant followed by a period of mechanical ventilation (prophylactic surfactant [PS]); prophylactic surfactant with rapid extubation to bubble nasal continuous positive airway pressure (intubate-surfactant-extubate [ISX]) or initial management with bubble continuous positive airway pressure and selective surfactant treatment (nCPAP). DESIGN/METHODS: Neonates born at 26 0/7 to 29 6/7 weeks' gestation were enrolled at participating Vermont Oxford Network centers and randomly assigned to PS, ISX, or nCPAP groups before delivery. Primary outcome was the incidence of death or bronchopulmonary dysplasia (BPD) at 36 weeks' postmenstrual age. RESULTS: 648 infants enrolled at 27 centers. The study was halted before the desired sample size was reached because of declining enrollment. When compared with the PS group, the relative risk of BPD or death was 0.78 (95% confidence interval: 0.59-1.03) for the ISX group and 0.83 (95% confidence interval: 0.64-1.09) for the nCPAP group. There were no statistically significant differences in mortality or other complications of prematurity. In the nCPAP group, 48% were managed without intubation and ventilation, and 54% without surfactant treatment. CONCLUSIONS: Preterm neonates were initially managed with either nCPAP or PS with rapid extubation to nCPAP had similar clinical outcomes to those treated with PS followed by a period of mechanical ventilation. An approach that uses early nCPAP leads to a reduction in the number of infants who are intubated and given surfactant.
Subject(s)
Continuous Positive Airway Pressure/methods , Infant, Premature , Pulmonary Surfactants/administration & dosage , Respiratory Distress Syndrome, Newborn/therapy , Confidence Intervals , Drug Administration Schedule , Female , Follow-Up Studies , Gestational Age , Humans , Infant, Newborn , Intubation, Intratracheal/methods , Male , Odds Ratio , Pregnancy , Respiration, Artificial/methods , Respiratory Distress Syndrome, Newborn/diagnosis , Respiratory Distress Syndrome, Newborn/mortality , Risk Assessment , Severity of Illness Index , Survival Rate , Time Factors , Treatment OutcomeABSTRACT
Humidified high-flow nasal cannula (HHFNC) therapy for neonates has become increasingly popular in recent years. It is frequently used in circumstances when continuous positive airway pressure (CPAP) might otherwise have been used. Limited evidence is available to support the specific role, efficacy, and safety of HHFNC in newborns. This evidence suggests that HHFNC provides inconsistent and relatively unpredictable positive airway pressure, but may be effective in the treatment of some neonatal respiratory conditions while being more user-friendly for caregivers than conventional CPAP. Concerns regarding infection risks have resulted in one major HHFNC device being withdrawn from the market before being recently reintroduced. Caution should be exercised in the use of HHFNC in neonates (eg, by limiting its use to relatively lower flows and to relatively larger neonates, while collecting and closely monitoring safety and efficacy data) until further evidence is available to clearly delineate its role, as well as to support its safety and efficacy.
