Physio-Control LIFEPAK CR Plus - Manual (Page 65)

LIFEPAK CR Plus and LIFEPAK EXPRESS Defibrillator Operating Instructions B-3
©2009-2010 Physio-Control, Inc.
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Shock Advisory System
Control of Shock Therapy
The Shock Advisory System causes the defibrillator to charge automatically when it detects the
presence of a shockable rhythm. When a shockable rhythm is detected, the defibrillator automatically
delivers a shock or instructs the user to deliver the shock by pressing the shock button.
Note: If the shock button is not pressed within 15 seconds, the system disarms and repeats the
analysis. The system also disarms if the patient impedance decreases suddenly or the patient
impedance goes outside the acceptable range for analysis. If none of these occur, the shockable rhythm
decision is not revised during charging or prior to shock.
Motion Detection
The Shock Advisory System detects victim motion independent of ECG analysis. A motion detector is
designed into the defibrillator
.
MOTION DETECTION can be configured to be ON or OFF . Refer to Section 6,
"Defibrillator Operating Settings".
A number of activities can create motion, including CPR, rescuer movement, patient movement, vehicle
movement, and some internal pacemakers. If variations in the transthoracic impedance signal exceed a
maximum limit, the Shock Advisory System determines that patient motion of some kind is present. If
motion is detected, the ECG analysis is inhibited. The operator is advised by a displayed message, a
voice prompt, and an audible alert. After 10 seconds, if motion is still present, the motion alert stops and
the analysis always proceeds to completion. This limits the delay in therapy in situations where it may
not be possible to stop the motion. However, the rescuer should remove the source of motion whenever
possible to minimize the chance of artifact in the ECG.
There are two reasons why ECG analysis is inhibited when the motion alert occurs, and why the rescuer
should remove the source of the motion whenever possible:
• Such motion may cause artifact in the ECG signal. This artifact may occasionally cause the Shock
Advisory System to reach an incorrect decision.
• The motion may be caused by a rescuer's interventions. To reduce the risk of inadvertently shocking
a rescuer, the motion alert prompts the rescuer to move away from the patient. This will stop the
motion and ECG analysis will proceed.
Nonshockable:
all other rhythms 433 >95% specificity 99.3% [98.5%]
Intermediate:
fine VF 4 Report only 100.0% [56.2%] sensitivity
Intermediate:
other VT 7 Report only 42.9% [17.0%] specificity
1 From Physio-Control ECG database.
2 Automatic External Defibrillators for Public Access Defibrillation: Recommendations for Specifying and Reporting
Arrhythmia Analysis Algorithm Performance, Incorporating New Waveforms, and Enhancing Safety. AHA Task Force on
Automatic External Defibrillation, Subcommittee on AED Safety and Efficacy. Circulation, 1997, Vol. 95, 1677-1682.
3 LCL = 90% exact one-sided lower confidence limit.
Table B-3 LIFEPAK CR Plus and LIFEPAK EXPRESS Defibrillator SAS Performance Table for Pediatric ECGs (Continued)
Rhythm Class
ECG Test 1
Sample Size
Performance Goal 2
Observed Performance
Sensitivity or Specificity [LCL] 3