Airway Management in CPR
- when ventilation is provided by mouth-to-mouth, a pocket mask, or a self-inflating bag-mask-valve circuit, then the ratio of ventilations to chest compressions should always be 2:30 irrespective of one or more rescuers. (1) Since the rescuer’s expired oxygen concentration is only 16-17%, oxygen rich ventilation must be substituted as soon as possible.
- once the airway has been secured by an endotracheal tube or combitube, then continuous ventilations and chest compressions should be given; ventilations at a rate of 2:30. This continuous, asynchronous basic life support is uninterrupted except for pulse checks, defibrillation or other procedures. There is no longer great emphasis in early tracheal intubation unless a skilled individual is present to prevent unnecessary delay of chest compression.
- if the arrest is due to an obstructed airway then ROSC may be impossible unless adequate oxygenation is achieved.
- in a witnessed cardiac arrest in the vicinity of a defibrillator, attempted defibrillation takes precedence over opening of the airway
- give high flow oxygen until ROSC
Alternative airway devices
Tracheal intubation attempted by untrained personal can lead to complication (such as oesophageal intubation) and cause prolonged pause in chest compression which will compromise coronary and cerebral perfusion. So alternative devices such as the classic laryngeal mask airway (cLMA), the laryngeal tube (LT) and the i-gel have been considered.
When using a laryngeal mask airway, continuous, asynchronous basic life support may be possible. However, if it is difficult to adequately ventilate whilst chest compressions are given, then basic life support must revert back to cycles of 2:30.
Tracheal Intubation
- do not interrupt chest compressions for more than 10 seconds to place tracheal tube.
- most important complication of tracheal intubation is unrecognised oesophageal intubation. So proper placement of tube must be confirmed by
- equal breath sounds over bilateral axillae
- no breath sounds over the epigastrium
- condensation in the tube
- symmetrical chest wall rising
- exhaled carbon dioxide (CO2) (does not differentiate bronchial intubation from tracheal). End-tidal CO2 detectors that include a waveform graphical display (capnographs) are the most reliable for verification of tracheal tube position during cardiac arrest. Initially due to insufficient pulmonary blood flow the exhaled CO2 might not be detected.
Cricothyroidotomy
If it is impossible to ventilate an apnoeic patient with a bag-mask, or to pass a tracheal tube or alternative airway device, delivery of oxygen through a cannula or surgical cricothyroidotomy may be life-saving.
Reference:
- Resuscitation Council (UK). Resuscitation Guidelines 2021.