6
H
a
rv
a
rd
A
p
p
a
ra
tu
s
In
s
p
ir
a
A
d
v
a
n
c
e
d
S
a
fe
ty
V
e
n
ti
la
to
r
U
s
e
r'
s
M
a
n
u
a
l
Publication 5404-001-REV-C
Introduction
Pressure Control Mode (Inspira ASVp Only)
The ventilator delivers gas to the patient until the user-selected pressure limit is
reached. Flow rate is automatically adjusted by the machine so that the pressure limit
is reached near the end of the inspiration time. Respiration frequency and I:E Ratio
determine the amount of time for inspiration and expiration phases.
Adjustable I:E Ratio
This option allows the user to select the ratio of inhalation to exhalation times when
advanced respiratory control is needed. This feature is intended to allow greater res-
piratory control for research. The default I:E Ratio is 50%.
Flow-Rate Monitoring (Future Feature)
Flow-rate monitoring will allow continuous monitoring of the rate at which the gas
is being delivered to the animal. This feature will also aid respiratory research.
Programmable Sigh Breath
Continuous, long-term ventilation combined with the force of gravity will cause the
animal’s lungs to begin to collapse. Introducing a larger than normal tidal volume
over-inflates the animal’s lungs, replicating a natural sigh. It allows the lungs to
expand and opens the collapsed alveoli. Sigh breaths are supported in both modes.
In the volume-controlled mode, a sigh tidal volume is used. In the pressure-controlled
mode, a sigh pressure limit is used.The frequency and volume of the sigh breath are
user selectable in volume-controlled mode. In the pressure-controlled mode, the fre-
quency and pressure of the sigh breaths are selectable.
Respiratory Assist
The Inspira ventilator supports Respiratory Assist in both volume-and pressure-con-
trolled modes.This feature is used to wean an animal off the ventilator.When the ani-
mal attempts to initiate a breath on its own, a pressure sensor detects the drop in air-
way pressure.This drop initiates a ventilation cycle.The sensitivity of the Assist Mode
is adjustable from –1 to –10 cmH2O. The ventilator lets the animal initiate breaths
independently as long as its breathing rate is greater than the respiration rate set by
the user or calculated by the microprocessor. If the animal does not try to initiate a
breath, Inspira warns the user.
Airway Pressure Monitoring
The ventilator monitors the pressure of gas delivered to the animal being ventilated.
This safety feature prevents the operator from over or under pressurizing the lungs
of the animal. When Inspira detects an over-pressurization condition it sounds an
alarm, stops the inspiration stroke, and then cycles to expiration. Inspira continues
to ventilate but does not deliver enough gas to over-pressurize the lungs.
Overpressure conditions may result from occluded or restricted airways. When
Inspira detects an under-pressurization condition it sounds an alarm. This condition
could result from an airway disconnect or large leaks. Once again, Inspira continues
to ventilate while requesting user intervention. These features ensure that the animal
is kept safe from improper ventilator setup.
PEEP (Inspira ASVp Only)
Positive end-expiratory pressure (PEEP) is settable in the Inspira ASVp in both volume
-and pressure-controlled modes.The PEEP is adjustable from 0 to 10 cm H2O.
