Guaranteed Tidal Volume with Volume Control Ventilation

Paramedic pushes the stretcher with the patient

Volume control ventilation defines the volume administered to the patient (tidal volume Vt as the control variable). Airway pressure results from the compliance of the lungs and the inhaled volume. 

A volume-controlled mode thus ensures that the patient will receive a specific tidal volume. The pressure limit ensures that there are no peak pressures that could harm the lungs.

WEINMANN Ventilators feature the following volume control ventilation modes:

  • IPPV (Intermittent Positive Pressure Ventilation): Volume control mandatory ventilation
  • S-IPPV (Synchronized Intermittent Positive Pressure Ventilation): Assisted volume control ventilation with a trigger time slot of 100% of the expiratory time
  • SIMV (Synchronized Intermittent Mandatory Ventilation): Assisted volume control ventilation with a trigger time slot of 20% of the expiratory time
  • SIMV + ASB (Synchronized Intermittent Mandatory Ventilation + Assisted Spontaneous Breathing): Assisted volume control ventilation with optional pressure support

IPPV: Intermittent Positive Pressure Ventilation

Curve diagram IPPV mode

The IPPV mode is used for mandatory, volume control ventilation with a fixed tidal volume and fixed frequency. This mode is used on patients who have no spontaneous respiration. However, a spontaneously breathing patient can breathe deeply and freely during expiration.

Once the maximum ventilation pressure (pMax) has been reached, the device maintains the pMax until the end of the inspiratory time and then switches to expiration. It is therefore possible that the set tidal volume will not be fully applied if the maximum ventilation pressure (pMax) has been reached during inspiration.

The following ventilation parameters can be set:

Vt: Tidal volume (breathing volume) in ml
Freq.: Ventilation rate in 1/min
PEEP: Positive end-expiratory pressure in mbar
pMax: Maximum inspiratory pressure in mbar
I:E: Inspiratory-expiratory time ratio

The volume-controlled IPPV ventilation mode is included with the following devices:

S-IPPV: Synchronized Intermittent Positive Pressure Ventilation

Diagram with ventilation curve for S-IPPV mode

The S-IPPV mode is a volume control ventilation mode with variable mandatory minute volume (MV). Throughout the entire expiratory phase, a trigger is active which enables the patient to trigger a new mechanical breath.

This means the patient has the option of increasing the respiratory rate and therefore the minute volume MV, and adapting these to his/her needs. As a rule this mode is used on patients who have inadequate spontaneous respiration.

Ventilation in the S-IPPV mode corresponds to ventilation in the IPPV mode with the difference that it is possible to synchronize ventilation with the patient's efforts to inhale. Since the setting for the respiratory rate is lower, the patient can trigger mandatory mechanical breaths spontaneously. A trigger time slot extending throughout the expiratory time is available for this synchronization. 

The following ventilation parameters can be set:

Vt: Tidal volume (breathing volume) in ml
Freq.: Ventilation rate in 1/min
PEEP: Positive end-expiratory pressure in mbar
InTr: Inspiratory trigger
pMax: Maximum inspiratory pressure in mbar
I:E: Inspiratory-expiratory time ratio

S-IPPV is available for:

SIMV: Synchronized Intermittent Mandatory Ventilation

Curve diagram for SIMV ventilation

The SIMV mode is used for volume control ventilation with a fixed mandatory minute volume. The patient can breathe spontaneously between the mandatory mechanical breaths and thereby increase the minute volume. During spontaneous respiration, the mandatory mechanical breath is synchronized with the patient’s breathing. The mandatory minute volume and the mandatory respiratory rate remain unchanged.

Once the maximum ventilation pressure (pMax) has been reached, the device maintains the pMax until the end of the inspiratory time and then switches to expiration. It is therefore possible that the set tidal volume will not be fully applied if the maximum ventilation pressure (pMax) has been reached during inspiration.

The following ventilation parameters can be set:

Vt: Tidal volume (breathing volume) in ml
Freq.: Ventilation rate in 1/min
PEEP: Positive end-expiratory pressure in mbar
pMax: Maximum inspiratory pressure in mbar
I:E: Inspiratory-expiratory time ratio

SIMV + ASB: Synchronized Intermittent Mandatory Ventilation + Assisted Spontaneous Breathing

Diagram with ventilation curve for SIMV+ASB mode

The SIMV + ASB mode is used for volume control ventilation with a fixed mandatory minute volume (MV). The patient can breathe spontaneously between the mandatory mechanical breaths and thereby increase the minute volume.

During spontaneous respiration, the mandatory mechanical breath is synchronized with the patient’s breathing. The mandatory minute volume and the mandatory respiratory rate remain unchanged.

The set maximum pressure limit (pMax) ensures the safety of the patient. The SIMV + ASB ventilation mode is also used as a mode for apnea ventilation. The patient can trigger a mandatory, pressure-controlled mechanical breath during a predetermined trigger time slot. The trigger time slot is available in the final 20% of expiratory time Te. For the rest of the time, the patient can breathe spontaneously or spontaneously with the aid of pressure support.

The following ventilation parameters can be set:

Vt: Tidal volume (breathing volume) in ml
Freq.: Ventilation rate in 1/min
PEEP: Positive end-expiratory pressure in mbar
pMax: Maximum inspiratory pressure in mbar
Δ pASB: Pressure support (relative to the set PEEP)
InTr: Inspiratory trigger
ExTr: Expiratory trigger
I:E: Inspiratory-expiratory time ratio

SIMV + ASB is available for: