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Resuscitation 659

produce a systolic blood pressure peak of 60–80 mmHg generally held belief is that ECC alone is better than no
(in adults) and a cardiac output of 20–30% of normal. 27,41 CPR at all. 46-48
With external chest compressions it takes time to reach
optimal levels of coronary perfusion pressure and, ulti- Devices to augment compression
49
mately, bloodflow. Any interruption to chest compres- As ECC supplies only 30% of normal cardiac output
sions therefore decreases the coronary perfusion pressure and 15% of normal cerebral blood flow, there is a great
42
and resultant blood flow, ultimately reducing survival. need to find ways to improve ECC. While no circulatory
After 30 compressions open the airway and give two adjunct is currently recommended, several are being
breaths. 43 routinely used in the preadmittance and in-hospital
20
Survival potentially improves when an individual receives settings. A few of the recent devices are outlined in
a higher number of chest compressions during CPR, even Table 24.4.
if the person receives fewer ventilations. Because of this, Given the limited available information on the outcome
it is recommended that a 30 : 2 compression-to-ventila- of any of these devices and the absence of evidence to
tion ratio is used in adults, children and infants regardless demonstrate these devices are superior to conventional
of the number of rescuers, and 3 : 1 for neonates. Having manual CPR, no device is currently recommended as a
noted this, in the advanced life support paediatric setting, routine substitute for manual CPR. 20
the compression ratio changes to 15 : 2 and a ratio of 3 : 1
for the newborn with any number of rescuers (see Table
24.3). Studies note that the average person may not only Practice tip
be reluctant to initiate mouth-to-mouth resuscitation
44
but will also take eight seconds to deliver one breath. CPR should commence if the patient is unconscious, unrespon-
45
When a rescuer is reluctant to perform rescue breaths, sive, not moving and not breathing, even if the patient is taking
external cardiac compression (ECC) without expired the occasional gasp.
air resuscitation (EAR) should be encouraged, as the

TABLE 24.3 CPR for adults, children and infants

Age Airway Compression (CPR) 1 or 2 person
Infants <1 year Jaw support or chin-lift (no Two fingers or two overlying thumbs on 30 : 2
head-tilt) the lower end of the sternum with hands PALS 15 : 2
encircling the chest, 100 beats/min
Younger child: 1–8 years Head-tilt more than infants but less heel of one hand, 100 beats/min 30 : 2
than adults PALS 15 : 2
Older child: 9–14 years Head-tilt two hands, 100 beats/min 30 : 2
PALS 15 : 2
Adult Head-tilt two hands, 100 beats/min 30 : 2
PALS = paediatric advanced life support.

TABLE 24.4 Augment compression devices

Device Description
Active compression–decompression (ACD-CPR) l utilises a small portable device to compress and decompress the chest (‘plunger method’)
l enhances ventilation and venous return by raising the negative intrathoracic pressure
139
which facilitates venous return, thus priming the heart for subsequent compressions.
Interposed abdominal compression combined l least technical device
(IAC) with CPR (IAC-CPR) l the abdomen is compressed (midway between the xiphisternum and the umbilicus)
alternately with the rhythm of chest compression
l results in increased resistance in the descending aorta, thus raising the coronary
perfusion pressure 140
l receives the highest recommendation 140
Non-invasive automated chest compression l utilises a load-distributing band (LDB) to compress the anterior chest 141
device (AutoPulse) l the device is built around a backboard that contains a motor.
l the motor tightens or loosens LDB around the patient’s chest.
l has demonstrated better coronary perfusion when compared to manual CPR 141