Airway management and ventilation

Airway management and ventilation Patients requiring resuscitation often have an obstructed airway, usually secondary to loss of consciousness, but occasionally it may be the primary cause of cardiorespiratory arrest . Obstruction of the airway may be partial or complete. It may occur at any level, from the nose and mouth down to the trachea .

Oxigen Mask

Recognition of airway obstruction The ‘look, listen and feel’ approach is a simple, systematic method of detecting airway obstruction. • Look for chest and abdominal movements. • Listen and feel for airflow at the mouth and nose. Once any degree of of obstruction is recognised , aply first basic air management : head tilt and chin lift , an alternative is jaw trust .

Oropharyngeal airways An estimate of the size required is obtained by selecting an airway with a length corresponding to the vertical distance between the patient’s incisors and the angle of the jaw . If the glossopharyngeal and laryngeal reflexes are present, vomiting or laryngospasm may be caused by inserting an oropharyngeal airway; thus, insertion should be attempted only in comatose patients.

Nasopharyngeal airways In patients who are not deeply unconscious, a nasopharyngeal airway is tolerated better than an oropharyngeal airway. Sizes of 6—7mm are suitable for adults. Insertion can cause damage to the mucosal lining of the nasal airway, with bleeding in up to 30% of cases .

Oxygen Give oxygen whenever it is available. A standard oxygen mask will deliver up to 50% oxygen concentration, providing the flow of oxygen is high enough. A mask with a reservoir bag (nonrebreathing mask), can deliver an inspired oxygen concentration of 85% at flows of 10—15 l min

Suction Use a wide-bore rigid sucker (Yankauer) to remove liquid (blood, saliva and gastric contents) from the upper airway. The sucker can provoke vomiting.

The pocket resuscitation mask It is similar to an anaesthetic facemask, and enables mouth-to-mask ventilation. It has a unidirectional valve, which directs the patient’s expired air away from the rescuer . Use a two-hand technique to maximise the seal with the patient’s face . Give two ventilations after each sequence of 30 chest compressions.

Without supplemental oxygen, the self-inflating bag ventilates the patient’s lungs with ambient air (21% oxygen). This can be increased to about 45% by attaching oxygen directly to the bag. If a reservoir system is attached and the oxygen flow is increased to approximately 10 l min, an inspired oxygen concentration of approximately 85% can be achieved. Try to achieve a good seal between the mask and the patient’s face, and to maintain a patent airway with one hand while squeezing the bag with the other hand .

Laryngeal mask airway (LMA) It is a wide-bore tube with an elliptical inflated cuff designed to seal around the laryngeal opening . Ventilation using the LMA is more efficient and easier than with a bag-mask. Disadvantages of the LMA are the increased risk of aspiration and inability to provide adequate ventilation in patients with low lung and/or chestwall compliance , in comparision with endotracheal intubation .

I-Gel

The Combitube It is a double-lumen tube introduced blindly over the tongue, and provides a route for ventilation whether the tube has passed into the oesophagus or the trachea .

Tracheal intubation Tracheal intubation is the optimal method of providing and maintaining a clear and secure airway . The advantage is :maintenance of a patent airway, which is protected from aspiration of gastric contents or blood from the oropharynx; ability to provide an adequate tidal volume reliably even when chest compressions are uninterrupted; the potential to free the rescuer’s hands for other tasks; the ability to suction airway secretions; and the provision of a route for giving drugs.

Tracheal intubation No intubation attempt should take longer than 30 s; if intubation has not been achieved after this time, recommence bag-mask ventilation. After intubation, tube placement must be confirmed and the tube secured adequately . Unrecognised oesophageal intubation is the most serious complication . Primary assessment includes observation of chest expansion bilaterally, auscultation over the lung fields bilaterally in the axillae (breath sounds should be equal and adequate) and over the epigastrium (breath sounds should not be heard) , and secondary use an exhaled carbon-dioxide detection device .

Securing the tracheal tube Tracheal intubation Cricoid pressure During bag-mask ventilation and attempted intubation, cricoid pressure applied by a trained assistant should prevent passive regurgitation of gastric contents and the consequent risk of pulmonary aspiration. Securing the tracheal tube Accidental dislodgement of a tracheal tube can occur at any time, but may be more likely during resuscitation and during transport. Use either conventional tapes or ties, or purpose-made tracheal tube holders.

Cricothyroidotomy Occasionally, it will be impossible to ventilate an apnoeic patient with a bag-mask, or to pass a tracheal tube or alternative airway device (patients with extensive facial trauma or laryngeal obstruction due to oedema or foreign material). Needle cricothyroidotomy is a much more temporary procedure providing only short-term oxygenation. Surgical cricothyroidotomy provides a definitive airway that can be used to ventilate the patient’s lungs until semi-elective intubation or tracheostomy is performed .