Non-invasive Ventilation (NIV)
Non-invasive ventilation (NIV for short) is a form of respiratory therapy for patients with difficulty absorbing enough oxygen or expelling carbon dioxide. It is a method for supporting breathing that manages without securing the airways. In contrast to invasive ventilation in which users introduce an endotracheal tube or a supraglottic airway device into the trachea for airway management, non-invasive ventilation uses an NIV/CPAP mask.
Non-invasive ventilation and its benefits
Compared to pure oxygen therapy, in non-invasive ventilation, a non-invasive ventilator maintains a continuous positive pressure in the lung. This pressure is normally applied via a face or nasal mask which fits the patient’s face. The positive pressure supports increased oxygen absorption and expulsion of CO₂.
At the same time, non-invasive ventilation has the advantage that it manages without the invasive measure of intubation. Early out-of-hospital use of non-invasive ventilation when treating acute respiratory failure may reduce both intubation rate and mortality1and thus reduce the risk of complications. Even if the hospital is only a short distance away, early non-invasive ventilation is a sensible step.2
Clinical pictures for treatment with non-invasive ventilation
Emergency medical services can use non-invasive ventilation for a variety of respiratory diseases, such as:
- (Exacerbated) chronic obstructive pulmonary disease (COPD)
- Acute pulmonary failure
- Cardiac pulmonary edema
- Asthma
- Carbon monoxide (CO) poisoning
WEINMANN Emergency’s modes of non-invasive ventilation as a solution
All WEINMANN Emergency ventilators (apart from MEDUMAT EasyCPR) offer the option of non-invasive ventilation (NIV): The WEINMANN NIV devices MEDUMAT Transport, MEDUMAT Standard² and MEDUVENT Standard have the following ventilation modes as non-invasive forms of ventilation via a mask:
- 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 therapy (CPAP).
In CPAP therapy, positive airway pressure is continuously maintained. CPAP can be used in the case of cardiac pulmonary edema or chronic obstructive pulmonary disease (COPD). CPAP therapy can likewise eliminate carbon monoxide (CO) more quickly than pure oxygen inhalation in carbon monoxide poisoning.3
The value set for CPAP/PEEP 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. CPAP mode is used exclusively on patients with adequate spontaneous breathing.
CPAP with Assisted Spontaneous Breathing (ASB)
Assisted Spontaneous Breathing (ASB) is another form of non-invasive ventilation. It supports patients who are able to breathe spontaneously but who have difficulty absorbing enough oxygen and/or expelling CO2 due to dyspnea 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 different diseases and conditions, such as exacerbated COPD, acute dyspnea or heart failure4.
BiLevel + ASB or BiPAP
BiPAP (Biphasic Positive Airway Pressure), 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 mode of two-stage pressure ventilationtogether with ASB (BiLevel + ASB) facilitates pressure-controlled ventilation in combination with free spontaneous breathing and adjustable pressure support. This mode is suitable for patients both with and without spontaneous breathing. During a predefined trigger time slot, the patient initiates a pressure-controlled breath. Otherwise it is possible to breathe either spontaneously or with pressure support.
Non-invasive BiLevel ventilation may be indicated in patients with acute pulmonary failure or exacerbated COPD.5
Pressure-Controlled Ventilation (PCV)/assisted Pressure-Controlled Ventilation (aPCV)
Pressure-Controlled Ventilation is another form of non-invasive ventilation. PCV mode facilitates Pressure-Controlled Ventilation at fixed pressure levels for patients with or without spontaneous breathing. In the case of spontaneous breathing, it is possible to breathe freely during expiration.
aPCV mode facilitates assisted Pressure-Controlled Ventilation at a specified respiratory rate. In the case of spontaneous breathing, the patient can increase the ventilation rate and ventilation is synchronized with breathing.
This mode is often used in patients being ventilated in a domestic setting.
WEINMANN Emergency’s modes of oxygen therapy as a solution
Airway management and ventilation are among the most important but also the most demanding measures in the emergency medical services.
WEINMANN Emergency ventilators permit oxygen therapy in which the patient inhales oxygen via a mask or a nasal cannula without breathing support. The demand or pre-oxygenation function saves oxygen, as it is administered exclusively during inspiration.
The following functions are available for pre-oxygenation or oxygen therapy:
- MEDUMAT Transport: Pre-oxygenation mode
- MEDUMAT Standard²: Inhalation mode, RSI Demand and Demand mode
- MEDUMAT EasyCPR: Demandflow mode
Demandflow mode for oxygen therapy and pre-oxygenation
In Demandflow mode, the devices switch to breath-controlled O2 inhalation. Inhalation can be carried out using a ventilation mask. A low inhalation (trigger) pulse causes oxygen to flow until a slight overpressure interrupts the flow; expiration then takes place via the patient valve. This saves oxygen, as it is administered exclusively during inspiration.
1Goodacre 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
2Hensel 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
3Caglar B et al: The Impact of Treatment with Continuous Positive Airway Pressure on Acute Carbon Monoxide Poisoning. Prehosp Disaster Med Dec: 588-591, 2019.
4Rochwerg B et al.: Official ERS/ATS clinical practice guidelines:noninvasive ventilation for acute respiratory failure. Guideline, 2017
5Rochwerg B et al.: Official ERS/ATS clinical practice guidelines:noninvasive ventilation for acute respiratory failure. Guideline, 2017