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Procedural Skills (SLO6)
Question 8 of 141
You are completing your refresher Advanced Life Support (ALS) Course and discussing emergency airway management. Regarding emergency airway management, which of the following statements is true?
Answer:
- An estimate of the size of oropharyngeal airway required may be obtained by selecting an airway with a length corresponding to the vertical distance between the patient's incisors and the angle of the jaw. Too small an airway may be ineffective, too large an airway may cause laryngospasm (slightly too big is more beneficial than slightly too small).
- For nasopharyngeal airway, sizes 6 - 7 mm are suitable for most adults (traditional sizing methods are not accurate).
- Noisy breathing in partial airway obstruction
- Inspiratory stridor (suggests obstruction at or above laryngeal level)
- Expiratory wheeze (suggests obstruction of lower airways)
- Gurgling (suggests presence of foreign material in upper airways)
- Snoring (arises when pharynx is partially occluded by tongue or palate)
- Use jaw thrust or chin lift in combination with manual in-line stabilisation in possible C-spine injury.
- When using an i-gel airway, select appropriate size (size 4 for most adults, or size 3 for small females, and size 5 for tall men).
Advanced Airway Management: Acute Airway Obstruction
Procedural Skills (SLO6)
Last Updated: 14th April 2023
Causes of airway obstruction
- Loss of consciousness
- Vomit or blood following regurgitation of gastric contents or in trauma
- Foreign bodies
- Laryngeal oedema from burns, inflammation or anaphylaxis
- Laryngeal spasm from upper airway stimulation or inhalation of foreign material
- Direct injury to larynx
- Extrinsic compression of airway e.g. from trauma, haematoma or tumour
- Obstruction below larynx
- Excessive bronchial secretions
- Mucosal oedema
- Bronchospasm
- Pulmonary oedema
- Aspiration of gastric contents
Recognition of airway obstruction
- Hoarseness (suggests functional laryngeal obstruction)
- Noisy breathing in partial airway obstruction
- Inspiratory stridor (suggests obstruction at or above laryngeal level)
- Expiratory wheeze (suggests obstruction of lower airways)
- Gurgling (suggests presence of foreign material in upper airways)
- Snoring (arises when pharynx is partially occluded by tongue or palate)
- Use of accessory muscles of respiration; the neck and shoulder muscles contract to assist the movement of the thoracic cage; there may also be intercostal and subcostal recession and a tracheal tug
- Paradoxical chest and abdominal movements described as 'see-saw breathing'
- Silent breathing in complete airway obstruction
- During apnoea, when spontaneous breathing movements are absent, complete airway obstruction is recognised by failure to inflate lungs during attempted positive pressure ventilation
- Agitation or altered consciousness
- Cyanosis (late sign)
Basic airway management
- Remove any obvious obstructing foreign body
- Airway opening techniques (head tilt/chin lift, jaw thrust)
- Clear secretions with suction and/or airway position
- Carefully remove any obvious visible foreign body with Magills' forceps or suction under direct visualisation
- Where possible, give high-concentration oxygen during attempt to relieve airway obstruction
- Airway adjuncts can be used to open an airway or maintain an airway requiring active manoeuvres
Airway manoeuvres
Head tilt and chin lift manoeuvre:
- Place one hand on the patient's forehead and tilt head back gently.
- Place the fingertips of the other hand under the point of the patient's chin and gently lift to stretch the anterior neck structures.
- Avoid head tilt in possible C-spine injury.
Jaw-thrust manoeuvre:
- With the index and other fingers placed behind the angle of the mandible, apply steady upwards and forward pressure to lift the mandible.
- Using the thumbs, slightly open the mouth by downward displacement of the chin.
- Use jaw thrust or chin lift in combination with manual in-line stabilisation in possible C-spine injury.
Simple airway adjuncts
Oropharyngeal airway:
- Available in a variety of sizes (most common sizes 2, 3 and 4 for small, medium and large adults respectively).
- An estimate of the size required may be obtained by selecting an airway with a length corresponding to the vertical distance between the patient's incisors and the angle of the jaw.
- Too small an airway may be ineffective, too large an airway may cause laryngospasm (slightly too big is more beneficial than slightly too small).
- Insert the airway in the 'upside-down' position as far as the junction between the hard and soft palate and then rotate it through 180 degrees and advance over the tongue. This rotation technique minimises the chance of pushing the tongue backwards and downwards.
Nasopharyngeal airway:
- Often better tolerated than an oropharyngeal airway - can be used in patients with intact airway reflexes without the significant risk of gagging, vomiting or aspiration.
- Sizes 6 - 7 mm are suitable for most adults (traditional sizing methods are not accurate).
- Select the nostril that appears larger and insert into the nostril directed posteriorly along the transverse floor of the nose.
- Contraindicated in basal skull fractures or significant facial injury with damage to the cribriform plate.
- May cause significant haemorrhage from the vascular nasal mucosa.
- If tube is too long, it may stimulate laryngeal or glossopharyngeal reflexes to produce laryngospasm or vomiting.
Supraglottic airways (SGAs)
In comparison with bag-mask ventilation alone, use of SGAs may enable more effective ventilation and reduce the risk of gastric inflation, regurgitation and aspiration. Furthermore, SGAs are easier to insert than a tracheal tube, and unlike tracheal intubation, they can generally be positioned without interrupting chest compressions.
I-gel airway:
- Insertion of i-gel is faster than most other airway devices.
- Select appropriate size (size 4 for most adults, or size 3 for small females, and size 5 for tall men).
- Lubricate back, sides and front of i-gel cuff with thin layer of lubricant.
- Grasp i-gel firmly along the integral bite block and position device so that i-gel cuff outlet is facing towards the chin of the patient.
- Ensure the patient is in the 'sniffing the morning air' position with head extended and neck flexed. Press chin down before inserting i-gel.
- Introduce the leading soft tip in the mouth in a direction towards the hard palate, glide the device downwards and backwards along the hard palate with a continuous but gentle push until a definitive resistance is felt.
- At this point the tip of the airway should be located at the upper esophageal opening and the cuff should be located against the larynx. The incisors should be resting on the bite block.
- Limitations:
- In presence of high airway resistance or poor lung compliance, risk of significant leak around cuff causing hypoventilation
- Uninterrupted chest compressions are likely to cause at least some leak when ventilation is attempted; attempt continuous compressions initially but if gas leakage results in inadequate ventilation, pause compressions for ventilation using ratio of 30:2
- Theoretical risk of gastric aspiration
- Risk of coughing, straining or laryngeal spasm if patient is not fully unconscious
Laryngeal mask airway (LMA):
- Select appropriate size (size 5 for most men and size 4 for most women), deflate cuff fully and lubricate outer face of cuff area with water-soluble gel
- Flex patient's neck slightly and extend head.
- Holding the LMA like a pen, insert into the mouth, advance tip behind the upper incisors with the upper surface applied to the palate until it reaches the posterior pharyngeal wall.
- Press the mask backwards and downwards around the corner of the pharynx until a resistance is felt as it locates in the back of the pharynx.
- If possible get an assistant to apply a jaw thrust after the LMA has been inserted in the mouth to aid successful placement.
- Connect the inflating syringe and inflate cuff with air (up to 40 mL for size 5 LMA and up to 30 mL for size 4 LMA).
- If insertion is satisfactory, the tube will lift 1 - 2 cm out of the mouth as the cuff finds its correct position and the larynx is pushed forward.
Tracheal intubation
The decision to intubate or not is often the first key decision in treating a critically ill or injured patient.
Tracheal intubation with a cuffed tube secures the airway and enables oxygenation and ventilation of the lungs. It protects the lungs from aspiration of blood or vomit and enables sedation to be given safely without the risk of respiratory compromise. However, the procedure can be technically difficult and requires trained personnel, and failed intubation or a misplaced tracheal tube can be rapidly lethal. The injection of drugs to achieve intubation also carries a further set of pharmacological complications, and commits the patient to ventilatory support.
Basic airway care and supplemental oxygen alway forms the mainstay of the immediate emergency airway management, however briefly applied. Intubation is indicated when the risks of continuing with basic airway support are greater than the risks of intubation.
Indications
- Apnoeic patient (unconscious patient with no significant respiratory effort or patient in cardiorespiratory arrest)
- Patient with obstructed/partially obstructed airway where basic airway care is ineffective
- Patient requiring invasive respiratory support for oxygenation or ventilatory failure
- Patient in whom basic airway care is effective, BUT whose predicted clinical course includes a high probability of airway obstruction, aspiration or ventilatory failure
Tracheal intubation in cardiac arrest:
| Advantages | Disadvantages |
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- Biochemistry
- Blood Gases
- Haematology
| Biochemistry | Normal Value |
|---|---|
| Sodium | 135 – 145 mmol/l |
| Potassium | 3.0 – 4.5 mmol/l |
| Urea | 2.5 – 7.5 mmol/l |
| Glucose | 3.5 – 5.0 mmol/l |
| Creatinine | 35 – 135 μmol/l |
| Alanine Aminotransferase (ALT) | 5 – 35 U/l |
| Gamma-glutamyl Transferase (GGT) | < 65 U/l |
| Alkaline Phosphatase (ALP) | 30 – 135 U/l |
| Aspartate Aminotransferase (AST) | < 40 U/l |
| Total Protein | 60 – 80 g/l |
| Albumin | 35 – 50 g/l |
| Globulin | 2.4 – 3.5 g/dl |
| Amylase | < 70 U/l |
| Total Bilirubin | 3 – 17 μmol/l |
| Calcium | 2.1 – 2.5 mmol/l |
| Chloride | 95 – 105 mmol/l |
| Phosphate | 0.8 – 1.4 mmol/l |
| Haematology | Normal Value |
|---|---|
| Haemoglobin | 11.5 – 16.6 g/dl |
| White Blood Cells | 4.0 – 11.0 x 109/l |
| Platelets | 150 – 450 x 109/l |
| MCV | 80 – 96 fl |
| MCHC | 32 – 36 g/dl |
| Neutrophils | 2.0 – 7.5 x 109/l |
| Lymphocytes | 1.5 – 4.0 x 109/l |
| Monocytes | 0.3 – 1.0 x 109/l |
| Eosinophils | 0.1 – 0.5 x 109/l |
| Basophils | < 0.2 x 109/l |
| Reticulocytes | < 2% |
| Haematocrit | 0.35 – 0.49 |
| Red Cell Distribution Width | 11 – 15% |
| Blood Gases | Normal Value |
|---|---|
| pH | 7.35 – 7.45 |
| pO2 | 11 – 14 kPa |
| pCO2 | 4.5 – 6.0 kPa |
| Base Excess | -2 – +2 mmol/l |
| Bicarbonate | 24 – 30 mmol/l |
| Lactate | < 2 mmol/l |
