Non-invasive Ventilation (NIV)
In non-invasive ventilation, a non-invasive ventilator maintains a continuous positive pressure in the lungs. The positive pressure can increase oxygen uptake and support the expiration of CO₂.
Definition: What is non-invasive ventilation (NIV)?
Non-invasive ventilation, or NIV for short, is a form of respiratory therapy for patients who have difficulty taking in enough oxygen or releasing enough carbon dioxide. It is a method for supporting breathing that works without securing the airways.
Difference between invasive and non-invasive ventilation
Unlike invasive ventilation, where a tracheal tube or supraglottic airway device is inserted into the trachea for airway management, NIV uses a full face mask that fits the patient’s face.
Indications for non-invasive ventilation
NIV can be used for a variety of respiratory disorders, such as:
- (Exacerbated) chronic obstructive pulmonary disease (COPD)
- Acute pulmonary failure
- Cardiac pulmonary edema
- Asthma
- Carbon monoxide poisoning
Contraindications
NIV is not suitable for all patient groups. The most important absolute contraindications include:
- Serious impairment of consciousness (e.g. non-hypercapnic coma), as the protective reflexes (e.g. cough reflex) are absent and the risk of aspiration increases.
- No spontaneous breathing or gasping, as invasive ventilation is required in these cases.
- Fixed or functional obstruction of the airways, as NIV cannot guarantee a flow of air across the obstruction.
- Gastrointestinal bleeding or ileus.
Advantages of non-invasive ventilation
The advantage of NIV is that it avoids intubation, which is an invasive procedure. Because it is minimally invasive, early out-of-hospital use, for example in the treatment of acute respiratory insufficiency, can reduce the intubation rate and mortality1 as well as the risk of complications such as those caused by sedation.
As no invasive interventions in the airways are necessary, the likelihood of infections or ventilator-associated pneumonia (VAP) is also significantly lower.2
Early non-invasive ventilation makes sense even if the patient is only a short distance from hospital3 Prehospital administration improves patient outcomes4 and helps to keep patients stable by correcting hypoxia or hypercapnia at an early stage.5
Risks of non-invasive ventilation
NIV is an effective method of treating acute or chronic respiratory failure and has several advantages over invasive ventilation. However, NIV also poses specific risks and possible complications that must be taken into account when using it.
Firstly, there is a risk of gastric bloating (aerophagia), which can cause nausea or even vomiting. In rare cases, this may lead to the patient’s stomach contents being aspirated.8
Secondly, dry airways and secretion retention can occur as a result of the air flow, and this can increase the risk of pneumothorax in previously damaged lungs.9
Forms of non-invasive ventilation offered by WEINMANN devices
All WEINMANN ventilators offer the option of NIV: Accordingly, the MEDUMAT Standard² and MEDUVENT Standard ventilators from WEINMANN offer the following forms of non-invasive ventilation:
- CPAP (Continuous Positive Airway Pressure)
- CPAP + ASB (Continuous Positive Airway Pressure + Assisted Spontaneous Breathing)
- BiLevel + ASB, aPCV (Assisted Pressure-Controlled Ventilation) and PCV (Pressure-Controlled Ventilation)
Continuous Positive Airway Pressure (CPAP)
One of the most frequent forms of non-invasive ventilation is continuous positive airway pressure (CPAP) therapy.
With CPAP therapy, positive airway pressure is maintained at all times. CPAP can be used in the case of cardiac pulmonary edema or chronic obstructive pulmonary disease (COPD). CPAP therapy can also eliminate carbon monoxide (CO) more quickly than pure oxygen inhalation in the event of carbon monoxide poisoning.10
The CPAP/PEEP setting is used to increase the pressure level of respiration in order to raise the functional residual capacity (FRC) of spontaneously breathing patients. Such patients are capable of breathing spontaneously at the specified pressure level without any kind of restriction. The CPAP mode is therefore only used when spontaneous breathing is sufficient.
CPAP with Assisted Spontaneous Breathing (ASB)
Assisted spontaneous breathing (ASB) is another form of non-invasive ventilation. It supports patients who can breathe spontaneously but have difficulty taking in sufficient oxygen and/or releasing CO2 due to respiratory distress or respiratory muscle weakness. If CPAP and ASB are combined, then the ventilator automatically switches on pressure support at the moment of inspiration.
CPAP with pressure support (ASB) can be used for various diseases and conditions such as exacerbated COPD, acute respiratory distress, and heart failure.11
BiLevel + ASB or BiPAP
Biphasic positive airway pressure (BIPAP), also known as BiLevel, is a non-invasive form of airway support in which one device generates two different airway pressures: a higher pressure during inspiration (inspiratory pressure) and a lower one during expiration (expiratory pressure).
BIPAP/BiLevel is frequently used in combination with adjustable pressure support (ASB). The two-stage positive pressure ventilation mode together with ASB (BiLevel + ASB) facilitates pressure-controlled ventilation in combination with free spontaneous breathing and adjustable pressure support. This mode can be used both with or without spontaneous breathing. During a predefined trigger window, the patient initiates a pressure-controlled breath. Otherwise, breathing can be spontaneous or with pressure support.
BiLevel may be indicated for acute respiratory failure or exacerbated COPD.12
Pressure-Controlled Ventilation (PCV)/assisted Pressure-Controlled Ventilation (aPCV)
Pressure-controlled ventilation is another form of NIV. The PCV mode facilitates pressure-controlled ventilation at fixed pressure levels for patients with or without spontaneous breathing. If there is spontaneous breathing, the patient can breathe freely during expiration.
The aPCV mode facilitates assisted pressure-controlled ventilation at a specified respiratory rate. If there is spontaneous breathing, the patient can increase its frequency, and ventilation is synchronized with breathing.
Non-invasive ventilation (NIV) with MEDUVENT Standard
Our video shows how NIV effectively provides respiratory support, minimizes risks and helps patients recover quickly. Ideal for respiratory therapy and emergency medicine practitioners looking for innovative solutions.
Oxygen therapy modes from WEINMANN as a solution
Airway management and ventilation are among the most important but also the most demanding measures in the emergency medical services.
Oxygen therapy, where the patient inhales oxygen via a mask or nasal cannula without ventilator support, is possible with MEDUMAT Standard². The Demand function saves oxygen, as the oxygen is exclusively administered during inhalation.
Demand mode for oxygen therapy
In Demand mode, MEDUMAT Standard2 switches to respiratory-controlled O2 inhalation. Inhalation can be carried out with a ventilation mask. A small inhalation (trigger) pulse causes oxygen to flow until a slight overpressure interrupts the flow and expiration takes place via the patient valve. This saves oxygen, as it is supplied exclusively during inspiration.
1 Mehta, S., & Hill, N. S. (2001). American Journal of Respiratory and Critical Care Medicine, 163(2), 540-577.
2www.thieme-connect.com/products/ejournals/pdf/10.1055/a-0760-7092.pdf
3 Goodacre S et al.: Prehospital noninvasive ventilation for acute respiratory failure: systematic review, network meta-analysis and individual patient data meta-analysis. Acad Emerg Med 21: 960-970, 2014
5 Hensel M et al.: Prehospital non invasive ventilation in acute respiratory failure is justified even if the distance to hospital is short. Multicenter, prospective, observational study, 2019
6 Bourdarias, J. P., Meignan, M., Huchon, G. J., et al. (2001). Noninvasive ventilation in the prehospital setting for acute respiratory failure. Intensive Care Medicine, 27(11), 1789-1795.
7 Brochard, L., Mancebo, J., Wysocki, M., et al. (1995). Noninvasive ventilation for acute exacerbations of chronic obstructive pulmonary disease. New England Journal of Medicine, 333(13), 817-822.
8 Chandra, D., & Kacmarek, R. M. (2012). Noninvasive positive pressure ventilation. Chest, 142(6), 1701-1711.
10 Caglar B et al: The Impact of Treatment with Continuous Positive Airway Pressure on Acute Carbon Monoxide Poisoning. Prehosp Disaster Med Dec: 588-591, 2019.
11 Rochwerg B et al.: Official ERS/ATS clinical practice guidelines:noninvasive ventilation for acute respiratory failure. Guideline, 2017
12 Rochwerg B et al.: Official ERS/ATS clinical practice guidelines:noninvasive ventilation for acute respiratory failure. Guideline, 2017