Phases of CPR

Phase I: Basic Life Support (BLS)

It involves three steps: ‘ABC’

A: Airway Maintenance

1. Removal of foreign matter.
2. Head-tilt/chin-lift maneuver or jaw thrust maneuver.
3. Oropharyngeal airway.
4. Endotracheal intubation, as early as possible.

• Since the loss of consciousness abolishes the normal muscle tone, the tongue and epiglottis fall back against the posterior pharyngeal wall and block the airway. This can be overcome by moving the lower jaw forwards, which lifts the tongue from the back of the throat and opens the airway up (Fig A)

Steps

• Head-tilt/chin-lift manoeuvre should not be employed when a cervical spine injury is suspected (jaw thrust manoeuvre is safer in presence of cervical spine injury and it is done by keeping both hands behind the angles of the mandible; and with a forward “movement”, mandible is lifted out of its socket and brought forward)
• Use of oropharyngeal airway
• Plastic/metal oropharyngeal airway can be used when available
• Figs A to C: Loss of consciousness is often accompanied by loss of submandibular muscle tone,
• (A) Occlusion of the airway by the tongue can be relieved by head-tilt, (Chin-lift)
• (B) Or a jaw thrust
• (C). In patients with possible cervical spine injury, the angles of the jaw should be lifted anteriorly without hyperextending the neck (Courtesy AHA)
• Correct size of the oropharyngeal airway has to be selected, size '4' for average male and size '3' for average female (if this is inserted in the semiconscious patient, it can be dangerous by causing laryngospasm/by inducing vomiting, thereby promoting pulmonary aspiration).

B: Breathing

Steps

a. Steps for mouth-to-mouth breathing (Fig):

• Kneel down on the patient’s right side
• Maintain airway all through
• Preferably have a handkerchief or a piece of gauze over the patient’s mouth.
• With the thumb and index finger of the left hand (the heel of which is pressing on the forehead), pinch the nostrils and keep them closed (Fig.)
• Seal your lips against those of the patient Fig)
• Blow into the patient’s mouth while watching the chest and abdomen of the patient. The chest should expand as much as in a normal breath
• The epigastrium should not get full
• After a breath, take your head away so that you can take another breath, and the patient’s passive exhalation can proceed (Fig.).

b. Bag-to-mask breathing using Ambu bag is preferred to expired air resuscitation

c. Endotracheal intubation

d. Ventilation with 100% oxygen is the best

C: Circulation

If a major arterial pulsation is not palpable, circulation must be immediately re-established with external cardiac compression Technique of external cardiac compression It is performed by compressing the lower half of sternum, so that the heart is compressed between the two bones—the movable sternum and the fixed vertebral column. This requires depression of the sternum by 5-7 cm and requires a pressure of about 70 lb.

Steps

• Ensure that the patient is on a hard flat surface. If the patient is on a soft mattress, something hard, such as a wooden board, must be slipped under the patient’s chest
• Kneel or stand at an adequate height by the side of the patient
• Feel the xiphisternum; keep two fingers above the xiphisternum and heel of the other palm just above the two fingers
• Remove the two fingers and keep the heel of that palm on top of the other, so that they now rest on the lower half of the sternum
• Exert adequate direct posterior pressure, avoiding any pressure at all laterally on the chest wall, to avoid injuries to ribs. The arms should be kept straight and the pressure should come from the shoulder, so that your whole-body weight is transmitted to the patient’s sternum. Compression by flexing and extending elbows is likely to be ineffective (Fig)
• If there is only one rescuer, compression and inflation of lungs must be alternated at a ratio of 15:2.
• If there are two rescuers, compression-inflation ratio can be about 5:1
• Between compressions, the pressure must be released completely to allow venous blood to flow into the heart; compression-relaxation ratio should be 1:1
• Check the effectiveness of cardiac compression by palpating the carotid or femoral pulses
• During compression, the pupils may diminish in size and consciousness may return, while the patient is still in cardiac arrest.