Physio Control Lifepak 20

Monitor

The LP20 is the ideal portable monitoring device for moderately ill patients. It can monitor 3-Lead ECG and pulse-oximetry (SpO₂).

The internal nickel-metal hydride battery is rechargeable and intended to be used for standby operation. A new, fully charged battery provides approximately 90 360-joule discharges, 70 minutes of pacing, or approximately 120 minutes of continuous monitoring before the defibrillator turns off.

Defibrillator

The LIFEPAK 20 uses a biphasic waveform for defibrillation. Research has shown that it has greater shock efficacy in patients with ventricular fibrillation (Review by Nichol et al., JACC, Dec. 2017).

Depending on the operating team (BLS or ALS team) the Lp20 can be run in different modes:

• AED Mode
• Manual Mode
• Synchronized Cardioversion

AED Mode

While the front console is closed (see picture) a simple 1-2-3 operation guides the BLS user through the process of the defibrillation. The default settings are consistent with 2005 American Heart Association (AHA) and European Resuscitation Council (ERC) guidelines. Prior to following the commands, the BLS user must verify that the patient is in cardiac arrest (unconscious, no respiration, no pulse). The American Heart Association recommends that AEDs must not be used in pediatric patients younger than eight years of age.

The  ANALYZE  button activates the Shock Advisory System (SAS) and the AED mode which guides the user with voice and visual prompts through each step.

According to the LP20 manual, the electrodes must be placed in the anterior-lateral (Lead II) position. The shock advisory algorithm does not reliably work with electrodes in the anterior-posterior position.

Manual Mode

Manual mode can be entered by pressing the Manual button located in the lower left corner of the door. This opens the door and automatically provides access to manual defibrillation and pacing. The clear and instructive front panel provides all important buttons in one place.

For pediatric patients (younger than 8 years of age) the energy levels are calculated per kilogram body weight: First shock 2 J/kg, second shock 4 J/kg, subsequent shocks =4 J/kg, maximum 10 J/kg or adult dose. For further information, please refer to Pediatric Cardiac Arrest Algorithm - 2015 Update (PDF).

An illuminated  AED MODE  LED indicates that the Continuous Patient Surveillance System (CPSS) is activated. It automatically evaluates the patient's ECG for a potentially shockable rhythm, i.e. ventricular tachycardia (VT) or ventricular fibrillation (VF). If a shockable rhythm is detected, the PUSH ANALYZE prompt occurs.

In case of an in-hospital cardiac arrest, skilled personnel trained in ACLS must exclude contraindications as follows:

• Dysrhythmias due to enhanced automaticity (digitalis toxicity, catecholamine-induced arrhythmia)
• Multifocal atrial tachycardia

In these conditions cardioversion is associated with a higher incidence of post-shock VT and VF. (AHA Guideline 2015 Update for CPR and ECC)

Synchronized Defibrillation

The LP20 is also capable of synchronized defibrillation (SYNC ON) by discharging the shock with the next detected R wave. This helps to avoid the vulnerable T-wave segment of the cardiac cycle. Indications for electrical cardioversion include supraventricular tachycardia (SVT), atrial fibrillation or flutter, and VT with pulse.

CPR Assistance

cprMAX™ Technology

cprMAX technology is designed to allow resuscitation protocols to maximize the quantity of CPR administered during treatment with an AED. AED protocols are aligned with the AHA and ERC Guidelines when the setup options are set as follows:

• Initial CPR: OFF
• PreShock CPR Time: OFF
• CPR Times: Default setting is 120 seconds
• Stacked Shocks: OFF
• Pulse Check: NEVER

According to AHA 205 guidelines, CPR should be provided while the AED pads are applied and until the AED is ready to analyze the rhythm. For witnessed adult cardiac arrest when an AED is immediately available, it is reasonable that the defibrillator be used as soon as possible.

Depending on local hospital protocols, it might be useful to use CPR FIRST setting that prompts the user to perform CPR immediately after the defibrillator is powered on. The AED will also prompt, IF YOU WITNESSED THE ARREST, PUSH ANALYZE, which provides the opportunity to end CPR early and proceed directly to analysis.

After each delivery of a shock, the device will advise to START CPR again. A countdown timer continues for the duration specified in the CPR TIME setup option (default 120 sec). Afterwards, the PUSH ANALYZE command is displayed again.

The AHA recommends minimal interruptions of chest compressions. A pulse check should not take longer than 10 seconds. If the rescuer cannot detect a pulse within that time-period, chest compressions should be started. Ideally, the pulse check is performed simultaneously with the check for no breathing or only gasping.

Non-invasive Transcutaneous Pacing (NTP)

In case of severe bradycardia, the LIFEPAK Defibrillator can deliver two types of pacing:

1. Demand pacing
2. Non-demand (asynchronous) pacing

The QUIK-COMBO electrodes are attached to the thorax in an anterior-lateral (apical) or anterior (pre-cordial) and posterior position. The LP20 pacer allows for continuous adjustment of the output current between 0 and 200 mA. The pacing rate can be set between 40 and 170 pulses per minute (ppm).

Data Management and Transmission of Data

Typically, the data memory of the LP20 can store up to 100 single waveform reports. Patient reports are stored as a CODE SUMMARY™ Critical Event Record, which includes patient information, event and vital signs logs, and waveforms associated with events, e.g. defibrillation. Patient reports can be transmitted to a PC-compatible computer via wireless, infrared communication (IrDA). Alternatively, the report can be printed with the in-built 50 mm printer.