Non-Invasive Ventilation: The Right Settings

With the correct settings, NIV is essential for effective prehospital emergency care. In critical situations, it alleviates the patient’s shortness of breath and minimizes the risk of potential complications. 

Find out in this article how correctly setting the NIV ventilator can significantly improve patient outcome.

How important is the correct setting for NIV?

Precise adjustment of the ventilation parameters for non-invasive ventilation is essential for successful therapy and patient safety. Incorrectly set parameters can lead to discomfort or ineffective ventilation.

NIV is particularly important in prehospital care, as it can avoid or delay endotracheal intubation. This reduces the risk of complications associated with invasive procedures.¹

NIV can also improve long-term survival: in acute respiratory insufficiency (ARI) in the context of acute exacerbated chronic obstructive pulmonary diesease (AECOPD), NIV reduces the mortality rate by up to 46%.² In addition, correctly set NIV usually leads to clinical improvement, for example by relieving respiratory distress and normalizing the respiratory and heart rate.³

The most important benefits of optimally set NIV are:

NIV settings

The NIV settings must be individually adapted to the pathophysiological conditions of the underlying respiratory insufficiency and the patient’s current clinical status. 

Depending on the clinical picture, the CPAP and BiLevel modes with or without pressure support (ASB/PSV) may be relevant for prehospital settings. 

During ongoing ventilation, continuous patient communication is important in order to make fine adjustments to the ventilation parameters as required and to improve patient comfort.

Generally, the recommendation is to initially set a moderate CPAP pressure (PEEP) in CPAP + ASB mode. If oxygenation and ventilation are not sufficient, pressure support (ASB/PSV) ) can be added in mode to ensure effective CO₂ elimination. A low trigger threshold makes it easier for the patient to initiate breathing support and thus reduces the work of breathing (WOB).

In addition, the expiratory trigger (ExTr) or inspiratory termination should be set to ≥ 25% of the peak flow. This ensures that the patient can breathe out promptly without having to “fight” against the ventilator.

An initial standard setting for NIV ventilation can be as follows:

• Spontaneous breathing mode, e.g. CPAP + ASB or PSV
• PEEP: 3-5 mbar, maximum 10 mbar
• ASB/PSV: 8-12 mbar (depending on indication)
• Increase ASB/PSV to 10-20 mbar, maximum 25 mbar⁶

Once NIV has been initially set, the ventilation parameters should be monitored continuously. Values such as respiratory rate, oxygen saturation (SpO₂) and end-tidal carbon dioxide (etCO₂) can provide information about the success of the therapy. 

NIV settings with COPD

As COPD is a common cause of hypercapnic acute respiratory insufficiency, there are specific settings for NIV in COPD.

We recommend a CPAP + ASB/PSV mode that supports spontaneous breathing. At the same time, a rapid rate of pressure increase (ramp) should be selected to make breathing easier for patients.⁷ The following parameters also apply to NIV: 

• High inspiratory pressures to ASB: 15-25 mbar
• PEEP: 6-8 mbar⁸
• I:E ratio: 1:2, 1:3 or 1:5
• Inspiratory time: 0.8-1.2 s⁹
• Aim: SpO₂ 88-92%

Starting NIV

Starting NIV in the emergency medical services is time-critical and requires the utmost care when setting the ventilation parameters. Accordingly, a structured approach makes a decisive contribution to the success of the therapy:

1. Check indications and contraindications
2. Consider sedation if agitation is severe
3. Identify the problem (ventilation or oxygenation disorder?) and adjust NIV with specific parameters¹⁰
4. Position the mask in a sitting or semi-sitting position
5. Looser fitting of the mask
6. Attach the mask after synchronization with the ventilator
7. Continuous assessment of NIV and settings based on clinical parameters, blood gas analysis and patient comfort

Close monitoring is essential in order to control NIV and recognize termination criteria at an early stage. The receiving hospital must also be informed in good time.

How long is non-invasive ventilation indicated for?

NIV is indicated as long as it brings about clinical improvement and can compensate for respiratory insufficiency. Increased alveolar ventilation and oxygenation or a subjective improvement in dyspnea indicate that therapy should be continued. 

If there is no improvement or clinical deterioration – such as increasing hypercapnia, progressive respiratory exhaustion or hemodynamic instability – a re-evaluation is required in order to escalate to invasive ventilation if necessary.

In prehospital emergency care, NIV is particularly indicated for acute respiratory insufficiency (ARI). A distinction is made between two types of clinical picture: hypoxemic and hypocapnic acute respiratory insufficiency.

Hypoxemic acute respiratory insufficiency – partial insufficiency

Hypoxaemic acute respiratory insufficiency (ARI), also known as partial insufficiency, is characterized by inadequate oxygenation in which the arterial oxygen partial pressure (paO₂) drops to < 60 mmHg, while the arterial carbon dioxide partial pressure (paCO₂) is normal or reduced.¹¹

The cause of hypoxemic ARI is a disturbance of pulmonary gas exchange, which can be caused by diffusion problems, a disturbed ventilation-perfusion ratio or a right-left shunt. In the latter case, venous, deoxygenated blood enters the arterial circulation without being enriched with oxygen by the lungs. Therefore, the primary therapeutic measure is the administration of oxygen.

In the case of a shunt, the primary therapy is oxygen administration, as NIV therapy alone remains ineffective without adequate oxygenation.

Settings for NIV of hypoxemic ARI in the prehospital setting 

Modified in accordance with the AGNN’s 2022 treatment recommendations for emergency medicine (AGNN = Arbeitsgemeinschaft in Norddeutschland tätiger Notärzte e.V. - Working group of emergency physicians working in North Germany)

In order to adapt NIV with settings for hypoxemic ARI (e.g. cardiac pulmonary edema), the following parameters should be set for WEINMANN ventilators:

• Mode: CPAP (without pressure support)
• Initial PEEP: 5 mbar
• Initial FiO₂: 100%

The aim of NIV with this setting is to achieve an oxygen saturation (SpO₂) of at least 94%. If the SpO₂ increases too much, the inspiratory oxygen concentration (FiO₂) can be gradually reduced. If the SpO₂ rise is insufficient, the PEEP should be increased to 7-10 mbar.

If the tidal volume is too low, the following measures are possible:

• Switch on pressure support of 5 mbar and increase gradually as required
• Set the inspiratory trigger as low as possible to facilitate spontaneous breathing

Hypercapnic acute respiratory insufficiency – global insufficiency

Hypercapnic acute respiratory insufficiency, also known as global insufficiency, is characterized by a reduced oxygen partial pressure < 60 mmHg and an increased carbon dioxide partial pressure paCO₂ > 45 mmHg,¹² causing the pH value to fall below 7.35.¹³ This leads to combined hypoxemia and hypercapnia.¹⁴

The causes are usually disorders of the respiratory pump, the respiratory drive or the respiratory mechanics.¹⁵ In order to support ventilation and improve CO₂ elimination, NIV is set with the aim of reducing the increased paCO₂ value and correcting the respiratory acidosis.

Settings for NIV of hypercapnic ARI in the prehospital setting

Modified in accordance with the AGNN’s 2022 treatment recommendations for emergency medicine (AGNN = Arbeitsgemeinschaft in Norddeutschland tätiger Notärzte e.V. - Working group of emergency physicians working in North Germany)

For NIV, the settings for hypercapnic ARI (e.g. COPD, asthma) on WEINMANN ventilators MEDUMAT Standard² and MEDUVENT Standard are as follows:

If SpO₂ increases, the FiO₂ value should be reduced accordingly. An insufficient tidal volume of less than 6 ml/kg can be corrected in two ways:

• Increasing the pressure support in small steps up to a maximum of 20 mbar
• In the case of pronounced ventilatory insufficiency, a switch to BiLevel/BIPAP ventilation can be considered.

Other indications

In addition, NIV ventilation is indicated in the following cases:

• Neuromuscular diseases
• OHS and OSAS¹⁶
• Prevention of extubation failure
• Weaning¹⁷
• Palliative care¹⁸

Optimal setting of NIV: indicators for effective therapy

Several signs and parameters indicate NIV and ventilator settings are being successful: 

• Increase in ventilation: decrease in etCO₂/paCO₂
• Increase in oxygenation: SpO2 > 85%
• Respiratory pump relief: reduction in respiratory rate and heart rate
• Subjective improvement
• Increase in pH value
• Increase in vigilance
• Reduction in dyspnea¹⁹

Deterioration or contraindications are regarded as termination criteria for NIV.

Termination criteria for NIV

Whether NIV can be performed or not depends on various contraindications. A distinction is made between absolute and relative contraindications. 

Absolute contraindications rule out NIV, while relative contraindications may still allow it under certain conditions. In these cases, however, staff must be on standby for intubation at all times.

Non-invasive ventilation – WEINMANN ventilator settings

NIV is optimally supported with the following settings on the WEINMANN ventilators MEDUMAT Standard² and MEDUVENT Standard: 

• MEDUMAT Standard² is our all-rounder with a wide range of ventilation modes. Thanks to its low weight, the ability to ventilate patients weighing as little as 3 kg, and a battery runtime of up to 10 hours, the device is ideal for emergency response.
• MEDUVENT Standard is a small and lightweight turbine-powered emergency ventilator that can ventilate for up to 7.5 hours at typical adult ventilaton settings, even without an external compressed gas supply. FiO₂ values of 21% to 100% are achieved, so that every form of respiratory insufficiency can be optimally treated. 

On the ventilators, NIV is set as follows:

1. Switch on ventilator
2. Select “New patient”
3. Set sex and height
4. Select ventilation mode
5. Set ventilation parameters PEEP, pMax and ΔpASB and start ventilation via “Start”
6. Connect the patient to the ventilator

With WEINMANN ventilators, ventilation is guaranteed to be in line with the guidelines. Would you like to find out more about ventilators and how they can be used? 

¹https://www.thieme-connect.com/products/ejournals/pdf/10.1055/a-0760-7092.pdf

²https://register.awmf.org/assets/guidelines/020-004l_Nichtinvasive-Beatmung-Therapie-akute-respiratorische-Insuffizienz_2024-01.pdf, p. 13.

³https://www.klinikum.uni-heidelberg.de/fileadmin/medizinische_klinik/Abteilung_4/pdf/Notarztkongress_5/08_Schulze-Schleithoff_NIV.pdf, p. 12.

⁴https://register.awmf.org/assets/guidelines/001-021l_S3_Invasive_Beatmung_2017-12.pdf, p. 14.

⁵https://www.klinikum.uni-heidelberg.de/fileadmin/medizinische_klinik/Abteilung_4/pdf/Notarztkongress_5/08_Schulze-Schleithoff_NIV.pdf, p. 5.

⁶ Lang, Hartmut (2020), Beatmung für Einsteiger, Theorie und Praxis für die Gesundheits- und Krankenpflege. [Ventilation for beginners, theory and practice for healthcare.] Berlin Heidelberg: Springer-Verlag, p. 73f.

⁷ Larsen, R. & Mathes, A. (2023): Beatmung [Ventilation]. 7th edition, Berlin Heidelberg: Springer Verlag, p. 97.

⁸ Lang, Hartmut (2020), Beatmung für Einsteiger, Theorie und Praxis für die Gesundheits- und Krankenpflege. [Ventilation for beginners, theory and practice for healthcare.] Berlin Heidelberg: Springer-Verlag, p. 75.

⁹ https://www.thieme-connect.com/products/ejournals/pdf/10.1055/a-0760-7092.pdf

¹⁰ https://nerdfallmedizin.blog/2019/12/07/nichtinvasive-beatmung-niv-ganz-neu-und-2019/

¹¹https://flexikon.doccheck.com/de/Hypoxische_respiratorische_Insuffizienz

¹²https://flexikon.doccheck.com/de/Hyperkapnische_respiratorische_Insuffizienz

¹³ Lang, Hartmut (2020), Beatmung für Einsteiger, Theorie und Praxis für die Gesundheits- und Krankenpflege. [Ventilation for beginners, theory and practice for healthcare.] Berlin Heidelberg: Springer-Verlag, p. 66.

¹⁴https://www.thieme-connect.de/products/ebooks/lookinside/10.1055/b-0034-35948#

¹⁵https://www.klinikum.uni-heidelberg.de/fileadmin/medizinische_klinik/Abteilung_4/pdf/Notarztkongress_5/08_Schulze-Schleithoff_NIV.pdf, p. 3.

¹⁶https://kem-med.com/wp-content/uploads/2024/08/SOP-Einleitung-einer-nicht-invasiven-Beatmung-NIV.pdf

¹⁷ http://thieme-connect.com/products/ejournals/pdf/10.1055/a-0760-7092.pdf

¹⁸ Lang, Hartmut (2020), Beatmung für Einsteiger, Theorie und Praxis für die Gesundheits- und Krankenpflege. [Ventilation for beginners, theory and practice for healthcare.] Berlin Heidelberg: Springer-Verlag, p. 62.

¹⁹ Larsen, R. & Mathes, A. (2023): Beatmung [Ventilation]. 7th edition, Berlin Heidelberg: Springer Verlag, p. 307.

²⁰ Lang, Hartmut (2020), Beatmung für Einsteiger, Theorie und Praxis für die Gesundheits- und Krankenpflege. [Ventilation for beginners, theory and practice for healthcare.] Berlin Heidelberg: Springer-Verlag, p. 62.