NELLCOR PURITAN BENNETT LP6 Plus, Technical Manual, Page: 46 / 104

Operating Modes Operating Modes Operating Modes Operating Modes
LP6 Plus, LP10, and LP20 Technical Manual
November 2000
Page 4-6 Page 4-6 Page 4-6 Page 4-6
When the adequate level of negative pressure, caused by patient
inhalation effort and determined by the
BREATHING EFFORT BREATHING EFFORT BREATHING EFFORT BREATHING EFFORT
control, is
sensed by the microprocessor, appropriate signals are sent to ini-
tiate the breath. If spontaneous breathing rates fail to reach the pre-
set rate, the microprocessor circuitry initiates a controlled breath,
and continues controlled breaths at the preset rate until spontane-
ous breaths resume.
If spontaneous breathing or a controlled breath is not sensed once
every 10 seconds, (breath rate less than 6 BPM) the apnea alarm
sounds and the ventilator delivers the set volume at 10 BPM at the
set inspiratory time.
Should control settings in this or any other mode demand breathing
rates or flows beyond the capability of the ventilator, the setting
error alarm sounds. Regardless of settings, the machine prevents I/
E ratios greater than 1:1.
During operation in this or any other mode, ventilation data, includ-
ing waveforms of flow, volume, and pressure, are obtainable using
the optional printer module.
SIMV
SIMV SIMV
SIMV
In this mode, intermittent mandatory breaths are synchronized with
the patient’s breathing effort near the rate set on the
BREATH RATE BREATH RATE BREATH RATE BREATH RATE
con-
trol. Stacking, i.e., a mandatory breath immediately following a
spontaneous breath without adequate exhalation time, is elimi-
nated.
The ventilator delivers a mandatory breath when the
SIMV
SIMV SIMV
SIMV
mode is
entered. It then establishes a time period during which patient effort
is monitored, and readies itself to deliver a breath. If the patient
makes sufficient effort to trigger a breath during the time period
(determined by the BPM setting), then the ventilator synchronizes a
delivered breath to the effort. Any additional breaths taken by the
patient during the same time interval are not assisted by the ventila-
tor. If the patient does not make sufficient effort to trigger a breath
by the end of the time period, the ventilator delivers a mandatory
breath.
At the end of each time period, the ventilator starts a new time
period and monitors for the first patient effort sufficient to trigger a
breath.
At settings of 1-5 BPM, the ventilator will enter the apnea mode if
there is not sufficient patient effort for 20 seconds. At that time the
apnea alarm sounds and 10 breaths per minutes are delivered. If
the patient resumes breathing spontaneously, the ventilator auto-
matically shifts from apnea to the SIMV mode.