Background
Noninvasive ventilation (NIV) can be defined as a ventilation modality that supports breathing by delivering mechanically assisted breaths without the need for intubation or surgical airway. [1] It is a popular method of adult respiratory management in both the emergency department (ED) and the intensive care unit (ICU), and it is increasingly used in the care of pediatric patients. [2] Besides avoiding the adverse effects of invasive ventilation, NIV has the added advantage of patient comfort. It has become an important mechanism of ventilator support both inside and outside the ICU. [3, 4, 5]
NIV is divided into two main types, negative-pressure ventilation (NPV) and noninvasive positive-pressure ventilation (NIPPV); the latter is further subdivided into several subtypes, including continuous positive airway pressure (CPAP), bilevel positive airway pressure (BiPAP), and volume-assured pressure support (VAPS). This article addresses these methods and briefly discusses heliox adjunct therapy.
Indications
NIV is indicated in neonates and infants as follows:
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Weaning from the ventilator
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Preventing collapse of the lung
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Minimal need for respiratory support, with good respiratory drive
NIV is indicated in children as follows:
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Impending respiratory muscle fatigue
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Chronic conditions (eg, Duchenne muscular dystrophy, other myopathies)
NIV is indicated in adults as follows:
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Chronic obstructive pulmonary disease with exacerbation
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Bilateral pneumonia
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Acute congestive heart failure with pulmonary edema
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Neuromuscular disorders
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Acute lung injury
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Weaning from ventilator - A 2009 meta-analysis indicated that NIV, as a method of weaning critically ill adults from invasive ventilation, was significantly associated with reduced mortality and ventilator-associated pneumonia [7] ; although NIV is currently employed for weaning from invasive ventilation in the acute setting, its use for weaning from prolonged ventilation is still occasional and has not been standardized [8]
A systematic review and meta-analysis by Glenardi et al compared NIV with high-flow nasal oxygen therapy in COVID-19 patients with acute respiratory failure (ARF). [9] NIV was found to have a higher success rate but also a significantly higher mortality. The authors suggested that high-flow nasal oxygen therapy should be considered before NIV in ARF associated with COVID-19 but noted that larger studies would be needed for better definition of the benefits of the former in this setting.
Contraindications
Absolute contraindications for NIV are as follows:
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Respiratory arrest or unstable cardiorespiratory status
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Uncooperative patients
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Inability to protect airway (impaired swallowing and cough)
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Trauma or burns involving the face
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Facial, esophageal, or gastric surgery
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Apnea (poor respiratory drive)
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Reduced consciousness
Relative contraindications for NIV are as follows:
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Extreme anxiety
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Morbid obesity
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Copious secretions
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Need for continuous or nearly continuous ventilatory assistance
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Lack of respiratory drive
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Diseases with air trapping (eg, asthma) - In a child on CPAP, periodic monitoring is required; if the clinical condition and arterial blood gases deteriorate despite CPAP support, intubation should be considered
Outcomes
A large retrospective cohort study by Lindenauer et al found that patients with severe COPD exacerbations who were treated with NIV at the time of hospitalization had lower inpatient mortality, shorter length of stay, and lower costs than patients who were treated with invasive mechanical ventilation. [10]
Another large retrospective cohort study found that in 1254 patients hospitalized with asthma exacerbation and receiving ventilatory support in the form of NIV or invasive mechanical ventilation, those successfully treated with NIV appeared to have better outcomes than those treated with invasive mechanic ventilation. [11] However, it is possible that NIV may have been used selectively in a lower-risk group.
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Nasal and nasopharyngeal prongs for continuous positive airway pressure (CPAP).
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Nasal prongs.
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Bilevel positive airway pressure (BiPAP) vision ventilator.
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Continuous positive airway pressure (CPAP) administered on adult patient.
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NIPPY ventilator (B&D Electromedical, Warwickshire, UK).
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Infant flow driver.
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Cuirass.
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Hayek oscillator.
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Heliox cylinders.
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Continuous positive airway pressure (CPAP) administered on child.
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Noninvasive ventilation. Video courtesy of Therese Canares, MD, and Jonathan Valente, MD, Rhode Island Hospital, Brown University.
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This whole-face mask for noninvasive ventilation is very useful, especially with pediatric patients, in that it covers entire face while maintaining transparency so that children can appreciate presence of parents or caregivers. It helps improve compliance and reduce anxiety.
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This full-face mask is suitable for noninvasive ventilation in that it provides seal over nose and mouth with minimal tension. Forehead cushion helps stabilize mask over front of forehead, thereby releasing pressure over nasal bridge.
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This cushioned nasal mask (least invasive mask available) provides comfort by covering only nostrils. Stretchable strap around neck helps secure mask in place. Pressure over nasal cartilages and nasal septum should be preventing by checking frequently.
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Noninvasive ventilation face mask that covers nose and mouth is shown with attachments, prior to fixation on patient’s face. Straps help secure mask tightly onto forehead and along sides of cheeks going around head, thereby maintaining tight seal.
