Philips Comprehensive Guide on Ventilation Control for V200 Vent Models

Ventilation Modes Common to VCV and

PCV

Chapter 7

Operating Theory

In Volume Control Ventilation and Pressure Control Ventilation, the operator can select between ventilation modes of Assist/Control, SIMV, and CPAP.

Assist Control Ventilation (A/C)

With the Assist/Control mode (refer to Figure 7-1or Figure 7-2), a minimal rate and tidal volume (or inspiratory pressure) are set by the operator. The patient can trigger the ventilator at a more rapid rate, but the operator set tidal volume (or inspiratory pressure) is delivered during each breath. The ventilator delivers only mandatory breaths. Assisted breaths may be either pressure or flow triggered. If the trigger setting is adjusted so that the patient cannot trigger the ventilator, all breaths will be delivered by the ventilator at the operator set rate and tidal volume (or pressure).

Synchronized Intermittent Mandatory Ventilation (SIMV)

SIMV is a ventilation mode where the patient is allowed to breathe spontaneously and the machine attempts to deliver volume (VCV) or pressure (PCV) mandatory breaths in synchrony with the patient’s effort at the operator set rate and volume (or pressure). This is accomplished by a combination of spontaneous and mandatory windows that open and close. The type of breath delivered depends upon whether the event during the window is patient initiated, operator initiated or time initiated. This logic is illustrated in Table 7- 1: “SIMV Logic”.

SIMV Logic

Current			Next
SIMV State	Inputs	Ventilator Response	SIMV State
Mand	Time Trigger	Deliver mandatory breath using operator	Mand
Window	(breath period	settings for mandatory breath type; Restart	Window
	timer expires)	breath period
Mand	Patient Trigger;	Deliver mandatory breath using operator	Spont
Window	Operator Trigger	settings for mandatory breath type	Window
Spont	Patient Trigger	Deliver a spontaneous breath using	Spont
Window		operator settings for spontaneous breath	Window
		type
Spont	Operator Trigger	Deliver a mandatory breath using operator	Spont
Window		settings for mandatory breath type	Window
Spont	Time Trigger	Restart breath period timer	Mand
Window	(breath period		Window
	elapses)

Table 7-1: SIMV Logic

REF 1057983 A Respironics V200 Ventilator Operator’s Manual 7-3