Types of Ventilation

Ventilation is a vital medical procedure to support or take over gas exchange in the lungs when the body is no longer capable of doing so. A wide variety of types or modes of ventilation makes it possible to cover a broad spectrum of medical conditions requiring ventilation.

Particular ventilation modes are available from WEINMANN Emergency depending on the ventilator selected and on the corresponding options.

Types of ventilation at WEINMANN Emergency

WEINMANN Emergency covers the following types of ventilation:

  • Volume-controlled ventilation
  • Pressure-controlled ventilation
  • Hybrid ventilation modes
  • Spontaneous ventilation modes
  • Special ventilation functions

The available types of ventilation include both standard types, such as IPPV or non-invasive CPAP therapy, and ventilation modes exclusive to WEINMANN, such as CCSV. A series of special ventilation functions uses preconfigured settings to facilitate work in emergency situations. RSI and CPR modes are examples of this, as are the emergency modes for infants, adults, and children.

Volume-controlled ventilation modes

IPPV, S-IPPV, SIMV, SIMV + ASB

In the context of volume-controlled ventilation (VCV), the patient is administered a previously specified minute volume up to a maximum ventilation pressure limit (pMax).

Tidal volume, respiratory rate, maximum ventilation pressure (pMax), and positive end-expiratory pressure (PEEP) can be set. Volume is supplied to the lungs as a function of these parameters until peak pressure (pPeak) is reached. In the subsequent plateau phase, pressure drops slightly until the end of the inspiration phase.

Tidal volume remains constant, even in instances where lung compliance changes quickly.

Indications for volume-controlled ventilation include neurological, muscular or lung diseases in which the respiratory musculature becomes weak, with the result that external support is required.

The methods of volume-controlled ventilation include: 

  • Intermittent Positive Pressure Ventilation (IPPV),
  • Synchronized Intermittent Positive Pressure Ventilation (S-IPPV), and
  • Synchronized Intermittent Mandatory Ventilation (SIMV). entilator does some of the work of breathing whilst the patient does the rest.

In S-IPPV and SIMV, the ventilator does some of the work of breathing whilst the patient does the rest.

  • + Guarantees constant ventilation 
  • + Allows accurate control of respiratory volume
  • - Potentially provides less protection to the lungs
  • - Risk of elevated peak pressure values if compliance is limited

Pressure-controlled ventilation modes

PCV, aPCV, BiLevel, BiLevel + ASB, CCSV

Pressure-controlled ventilation (PCV) specifies the pressure level to be reached during inspiration and expiration. Ventilation pressure (pInsp), respiratory rate, maximum ventilation pressure (pMax), and positive end-expiratory pressure (PEEP) can be set by the user. In pressure-controlled ventilation, the tidal volume administered results from the patient’s resistance (airway resistance) and compliance (degree to which the lung can expand). In the event of increased resistance and/or reduced compliance, it is possible for reduced volume to be administered whilst pressure remains the same, for example (this is compared to a situation with normal values for resistance and compliance).

The starting point for the ventilation cycle is a specified pressure level – positive end-expiratory pressure (PEEP) – which is to be maintained and which keeps the airway open. In the case of inspiration, the patient is supplied with respiratory gas until a specified inspiratory pressure (pInsp) has been reached. This pressure is maintained for the duration of inspiration. On expiration, the pressure level is reduced back to PEEP level and the ventilation cycle begins again.

The decelerating inspiratory flow in this process ensures better oxygenation and lower airway pressures.

Pressure-controlled ventilation is indicated in the case of neurological or muscular diseases which weaken the respiratory musculature and in the case of lung diseases such as acute respiratory distress syndrome (ARDS).

Particular types of pressure-controlled ventilation are Assisted Pressure-Controlled Ventilation (aPCV), BiLevel Positive Airway Pressure (BiLevel, also called BiPAP) and Chest Compression Synchronized Ventilation (CCSV) developed especially for resuscitation.

  • + Stops the set pressure being exceeded
  • + Guarantees lower airway pressures
  • + Cuts the risk of barotrauma
  • + Prevents harmful peak pressures [1]
  • - Lack of reliability with regard to the tidal volumes administered, which is why flow measurement is mandatory in pressure-controlled ventilation

Hybrid ventilation modes

PRVC, PRVC + ASB

The hybrid type of ventilation Pressure-Regulated Volume-Controlled Ventilation (PRVC) was developed to benefit from the advantages of both volume-controlled and pressure-controlled ventilation.

This combines volume-controlled ventilation with the decelerating flow of pressure-controlled ventilation. Tidal volume, respiratory rate, maximum ventilation pressure (pMax), and positive end-expiratory pressure (PEEP) can be set by the user.

Within a test breath, the ventilator is used to select inspiratory pressure such that target tidal volume is achieved by pressure-controlled mechanical breaths.

The pressure level is constantly adapted “breath-by-breath” and set to the lowest level. PRVC can be used in combination with Assisted Spontaneous Breathing (ASB) to support inadequate spontaneous breathing with pressure.

  • + More consistent ventilation of the lung
  • + Constant tidal volume
  • + Patient can largely determine ventilation rhythm, ventilation cycle, and duration of inspiration themselves
  • + Reduces the risk of barotrauma
  • - Quantity of ventilation remains constant, regardless of the patient’s own breathing
  • - Not particularly widespread, so may be a lack of practical experience

Spontaneous ventilation modes

CPAP, CPAP + ASB

Spontaneous ventilation modes such as Continuous Positive Airway Pressure (CPAP) are frequently used by emergency medical services in the context of non-invasive ventilation.

In CPAP, breathing is not controlled, but effected independently via a ventilation mask or helmet. The ventilator simply supports spontaneous breathing. The set PEEP level is always reached at the end of every ventilation cycle. CPAP is usually used in the case of oxygenation and ventilation disorders.

A distinction is made here between the following modes:

  1. CPAP: In pure CPAP, a positive inspiratory flow is delivered continuously, regardless of the patient’s spontaneous breathing. The patient can breathe independently at the set CPAP pressure level.
  2. CPAP + ASB: CPAP in combination with Assisted Spontaneous Breathing (ASB) detects the patient’s efforts to breathe in, and synchronizes delivery of pressure support with them, making it easier for the patient to breathe.

In both modes, it is possible to add mechanical apnea ventilation which is initiated whenever the patient does not breathe spontaneously.

  • + Compared to pure oxygen inhalation, improves oxygenation and decarboxylation
  • + Relieves the patient of respiratory effort
  • + Can be used non-invasively via the mask
  • - Cannot be used on unconscious patients

You can find a clear infographic on modes of mechanical ventilation here.
Download infographic

Special ventilation functions

CPR, RSI, Manual

WEINMANN Emergency has developed special ventilation functions to support the workflow in particular emergency situations. These functions are used particularly in emergency situations such as resuscitation or anesthesia induction.

Manual mode is used mainly in cardiopulmonary resuscitation (CPR) and in anesthesia induction (Rapid Sequence Induction, RSI). It allows the patient to be supplied with mechanical breaths on an individual basis as required. The mechanical breaths in WEINMANN Emergency ventilators are initiated by a button (MEDUtrigger) instead of a bag-valve mask. This special function can thus replace bag mask ventilation.

[1] Larsen R. Maschinelle Beatmung und NIV [Mechanical ventilation and NIV]. Anästhesie und Intensivmedizin für die Fachpflege. 2016 Jun 14:745–95. German. doi: 10.1007/978-3-662-50444-4_56. PMCID: PMC7531439; see objectives of ventilation: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7531439/