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Ventilación mecánica III: ventilación no invasiva
La ventilación con presión positiva no invasiva (NIPPV), la presión positiva continua en las vías respiratorias (CPAP) y la presión positiva binivel e…
La ventilación no invasiva, o VNI, proporciona soporte ventilatorio sin insertar una vía respiratoria artificial.
Este tipo de ventilación se utiliza en pacientes con insuficiencia respiratoria que están conscientes y pueden respirar de forma independiente, pero requieren asistencia para mejorar el intercambio de gases.
Los dos tipos de VNI son los ventiladores de presión negativa y la ventilación con presión positiva no invasiva (PPPPN).
Un ventilador de presión negativa, que se asemeja a una coraza, crea un vacío alrededor del pecho o el cuerpo para llevar aire a los pulmones, simulando la respiración.
Reduce de forma intermitente la presión intratorácica, precipitando aire hacia las vías respiratorias superiores, seguido de una espiración pasiva cuando la máquina se apaga.
El siguiente es el NIPPV, que utiliza mascarillas o dispositivos nasales para mantener la presión prescrita.
Dos tipos de NIPPV son la presión positiva continua en las vías respiratorias, o CPAP, y la presión positiva de dos niveles en las vías respiratorias, o BiPAP.
La CPAP proporciona presión positiva continua en las vías respiratorias, manteniendo los alvéolos abiertos y previniendo la insuficiencia respiratoria.
Por el contrario, BiPAP controla las presiones inspiratorias y espiratorias, proporcionando ventilación de soporte de presión.
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Q1: What is noninvasive ventilation and how does it differ from invasive ventilation?
Noninvasive ventilation (NIV) provides ventilatory support without inserting an artificial airway, making it suitable for conscious patients with respiratory failure who can breathe independently. Unlike mechanical ventilation invasive ventilation, NIV uses facemasks or nasal devices to deliver pressure support, reducing infection risk and allowing patients to maintain natural airway protection while receiving respiratory assistance.
Q2: What are the two main types of noninvasive ventilation?
The two main types of noninvasive ventilation are negative-pressure ventilators and noninvasive positive-pressure ventilation (NIPPV). Negative-pressure ventilators create a vacuum around the chest to draw air into the lungs, simulating natural breathing. NIPPV uses facemasks or nasal devices to maintain prescribed pressure and is further divided into continuous positive airway pressure (CPAP) and bilevel positive airway pressure (BiPAP).
Q3: How does continuous positive airway pressure (CPAP) work?
CPAP delivers continuous positive airway pressure throughout the breathing cycle, keeping alveoli open and preventing respiratory failure. This constant pressure maintains airways in an open state, making CPAP especially beneficial for treating obstructive sleep apnea and other conditions where airway collapse occurs during breathing.
Q4: What is the key difference between CPAP and BiPAP?
CPAP maintains constant positive pressure throughout the entire breathing cycle, while bilevel positive airway pressure (BiPAP) independently controls inspiratory and expiratory pressures. BiPAP provides two distinct pressure levels via a nasal or oral mask, offering greater comfort and flexibility for patients requiring ventilatory assistance, particularly at night.
Q5: What patient conditions benefit from noninvasive positive-pressure ventilation?
Noninvasive positive-pressure ventilation (NIPPV) is suitable for patients with acute or chronic respiratory failure, acute pulmonary edema, chronic obstructive pulmonary disease (COPD), chronic heart failure, and sleep-related breathing disorders. NIPPV reduces nosocomial infection risk compared to invasive methods while providing adequate respiratory support without requiring intubation.
Q6: How does a negative-pressure ventilator function?
A negative-pressure ventilator, resembling a cuirass, creates a vacuum around the chest or body to draw air into the lungs. It intermittently reduces intrathoracic pressure, rushing air into the upper airway, followed by passive expiration when the machine cycles off, thereby simulating natural breathing mechanics.
Q7: What factors determine the choice between different noninvasive ventilation methods?
The choice between noninvasive ventilation methods depends on the patient's clinical condition, comfort level, and healthcare provider expertise. Each type has distinct advantages and disadvantages; CPAP suits constant pressure needs, BiPAP offers dual-pressure flexibility, and negative-pressure ventilators provide an alternative for specific patient populations requiring different support mechanisms.