Main stages of cardiopulmonary resuscitation
The resuscitation protocol is traditionally divided into four consecutive steps:
- I — Airway management.
- II — Artificial lung ventilation (mechanical ventilation).
- III — Chest compressions.
- IV — Differential diagnosis, pharmacotherapy, and defibrillation.
The specific feature of the procedure is that stages one through three can be performed in out-of-hospital settings. This basic care can be provided by bystanders without specialized medical training if they possess the relevant practical skills. The final, fourth stage is specialized: it is performed exclusively by ambulance team physicians and intensive care unit specialists.
Causes of obstruction and oropharyngeal clearance (Stage I)
The first stage is critically important, as further ventilation is pointless without free oxygen access. An unconscious victim frequently develops mechanical asphyxia. The main causes of upper airway obstruction include: accumulation of mucus, sputum, vomit, blood clots, foreign body aspiration, and tongue displacement.
Algorithm for initial mechanical oropharyngeal clearance:
- Positioning the patient. The victim must be placed strictly supine on a hard surface.
- Preparation for clearance. To facilitate fluid drainage, the patient's head should be turned to the side.
- Opening the mouth. Performed by opening the jaws using the crossed thumb and index finger of the left hand.
- Inspection and clearance. The rescuer mechanically removes contents from the oral cavity and pharynx. This is done using a handkerchief or gauze napkin wrapped around the index or middle finger of the right hand (the fabric is needed to improve grip and protect the fingers).
Relief of tongue displacement: Triple airway maneuver (Safar method)
Tongue displacement is the most common cause of complete airway obstruction during loss of consciousness. The pathogenesis of this condition is due to the sharp decrease in the muscle tone of the mandible and neck in an unconscious state. The base of the tongue shifts toward the posterior pharyngeal wall, completely blocking the air passage.
To restore patency, the patient's head is turned straight and the triple airway maneuver is applied, consisting of three actions:
- Head tilt. Extension of the cervical spine occurs. The rescuer places one hand on the victim's forehead (fixing the head) and places the other under the neck. During the tilt, the muscles of the floor of the mouth are stretched, and the mandible shifts along with the base of the tongue, opening the pathway for air.
- Jaw thrust. The angles of the mandible are gripped with both hands (or one hand on the chin) followed by traction of the jaw forward and upward. This maneuver additionally shifts the base of the tongue forward, reliably opening the entrance to the larynx.
- Opening the mouth. The final element of the maneuver, necessary to initiate artificial ventilation.
Use of airways
To maintain upper airway patency and reliably prevent recurrent tongue displacement, auxiliary devices are used, in particular, the oropharyngeal Guedel airway.
Functions of the device:
- Creates a rigid framework inside the victim's oral cavity.
- Physically presses down the base of the tongue, preventing it from blocking the airways.
- Provides a constant and free flow of air directly into the larynx.
The airway is inserted into the oral cavity taking into account the anatomical curvature of the tongue and palate. When properly placed, the distal end of the tube reaches the pharynx, while the proximal end (flange) remains outside at the patient's lips.
Briefly: answers to topical questions
What is the correct ratio of chest compressions to rescue breaths during basic CPR?
The correct ratio of chest compressions to rescue breaths depends on the patient's age.
| Patient category | Ratio (compressions : breaths) |
|---|---|
| Adults | 30:2 |
| Children during two-rescuer resuscitation | 15:2 |
| Neonates | 3:1 |
Also, one of the algorithms indicates a cycle of 3 chest compressions and 1 breath without specifying age.
What depth of chest compressions is required during external cardiac massage in adults?
The depth of chest compressions during external cardiac massage in adults varies depending on the applied standards. It should range from 3 to 5 cm, though a number of algorithms indicate a displacement of at least 5 cm. Additionally, compression depth may be determined anatomically and be approximately one-third of the anteroposterior diameter of the patient's chest.
What pharmacological agents are used at the specialized stage of cardiopulmonary resuscitation?
At the specialized stage of cardiopulmonary resuscitation, solutions of epinephrine, calcium chloride, and sodium bicarbonate are used.
- Epinephrine — 0.1% solution, 1 ml, diluted in 10 ml of 0.9% sodium chloride solution.
- Calcium chloride — 10% solution, 10 ml.
- Sodium bicarbonate — 2% solution, 20 ml.
Medicinal agents are administered intravenously or intracardially. Epinephrine can also be administered endotracheally — via an endotracheal tube or by tracheal puncture.
At what rate per minute should chest compressions be performed during external cardiac massage?
The rate of chest compressions varies depending on the applied algorithm and the patient's age.
| Category / Standard | Compression rate per minute |
|---|---|
| Universal standard | 100–120 |
| Adults | 60 or at least 100 |
| Children under 10 years | 80 |
| Neonates | 90 or 120 |
To maintain a stable rhythm, it is recommended to count aloud.
What methods of artificial lung ventilation exist at the pre-hospital stage?
At the pre-hospital stage, apparatus-free (expired air) and mechanical methods of artificial lung ventilation are used.
- Non-apparatus methods — air insufflation via "mouth-to-mouth", "mouth-to-nose", and "mouth-to-mouth and nose" methods in infants under 1 year of age.
- Apparatus methods — manual ventilation using a self-inflating bag (Ambu bag) as well as portable devices RPA-1 and RDA-1.
Mechanical ventilation can be performed using an S-shaped airway tube. For infection control purposes, manipulations must be performed using barrier devices.
What are the clinical signs of effective cardiopulmonary resuscitation?
The clinical signs of effective cardiopulmonary resuscitation are indicators of restored perfusion and oxygenation.
- Hemodynamics — appearance of a palpable pulse wave in major (carotid, femoral) and subsequently peripheral arteries.
- Microcirculation — regression of pallor and cyanosis, return of physiological pink coloration to the skin and visible mucous membranes.
- Neurological signs — pupillary constriction (miosis) and restoration of their reaction to light.
- Respiration — onset of spontaneous respiratory excursions.
For quick memorization of Safar's triple airway maneuver, use the algorithm: Head tilt, Chin lift, Open mouth. These three movements clear the entrance to the larynx.
Class and exam questions
Can CPR be performed without a medical education?
Yes, the first three steps (ensuring airway patency, artificial ventilation, cardiac massage) can be performed out-of-hospital by anyone with appropriate practical skills.
Why does mechanical asphyxia occur during loss of consciousness?
Due to a sharp decrease in the tone of the neck and lower jaw muscles, the tongue base shifts toward the posterior pharyngeal wall, completely blocking the airways.
How to properly clear the oral cavity mechanically before mechanical ventilation?
The head is turned to the side, and the mouth is opened using crossed fingers of the left hand. Clearance is performed with the second or third finger of the right hand, pre-wrapped in gauze or a handkerchief.
What else to study on this topic
- Stage II: Technique of artificial lung ventilation (mechanical ventilation)
- Stage III: Rules for performing external chest compressions
- Differential diagnosis in cardiac arrest (Stage IV)
- Drug therapy within resuscitation measures
- Indications and algorithms for performing defibrillation
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