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Ventilation and Oxygenation Management 385

coils can however be irreversibly compressed by a strong PROCEDURE
bite that occludes the airway. Reinforced tubes also The patient is preoxygenated to minimise desaturation
increase the risk of tracheal damage and therefore should during apnoea and laryngoscopy, commonly via bag
be replaced with a standard endotracheal tube on arrival and mask, although other methods such as non-invasive
in the ICU. Most endotracheal tubes have a ‘Murphy eye’, ventilation have been suggested. Intubation in ICU is
24
an oval-shaped hole in the side of the tube between the usually performed via laryngoscopy with insertion of an
cuff and the end of the tube that provides a patent aper- oral ETT. Intubation may be performed using a fibreoptic
ture if the distal opening is occluded. 22
bronchoscope when difficulty is encountered, or for nasal
intubation.
PREPARATION FOR INTUBATION
Adequate preparation of the patient, equipment and Oral vs Nasal Intubation
environment, as well as strong knowledge of emergency Oral intubation is preferred unless there are specific indi-
procedures is important to ensure safe and efficient intu- cations for nasal intubation. Oral intubation is easier to
bation. Up to 50% of patients undergoing endotracheal perform and allows use of a larger diameter tube. While
intubation in ICU will experience a complication; 28% nasal intubation provides better splinting for the ETT and
will have a serious complication, including hypoxaemia, facilitates oral hygiene, it can damage nasal structures,
circulatory collapse, cardiac arrhythmia, cardiac arrest, is contraindicated in skull fractures and increases
oesophageal intubation, aspiration and death. 23 the risk of maxillary sinusitis and ventilator-associated
pneumonia. 25
Patient Preparation Cricoid Pressure
If appropriate, and time permits, explain the procedure
to the patient and family. Prepare the patient with: Cricoid pressure (Sellick manoeuvre) was introduced in
the 1960s to prevent aspiration of gastric contents during
● reliable intravenous access established to allow rapid intubation. The oesophagus lies behind and in line with
fluid and drug administration the trachea. The cricoid cartilage, situated below the
● accurate blood pressure monitoring (preferably thyroid prominence, is a closed tracheal ring which, when
intra-arterial) compressed, closes the oesophagus while the trachea
● continuous oxygen saturation and ECG monitoring remains open. Cricoid pressure is performed by placing
● nasogastric tube (if in situ) should be aspirated and your thumb on one side of the patient’s trachea, middle
placed on free drainage finger on the other side and index finger directly on the
● positioned supine in the ‘sniff’ position cricoid. Although widely used over the last 50 years, its
26
efficacy is being questioned as technique is frequently
Equipment and Drugs poor, and there is wide anatomical variation in the exact
27
All equipment should be checked immediately prior to orientation of the oesophagus in relation to the trachea. 28
intubation, including
Backwards, Upwards, Rightward
● oxygen supply Pressure Manoeuvre
● suction supply, with a range of Yankaeur and Y-suction The backwards, upwards, rightward pressure (BURP)
catheters manoeuvre on the thyroid cartilage was introduced in the
● laryngoscope blades and holder are compatible, with mid-1990s to improve visualisation during difficult laryn-
a functioning light goscopy. The patient’s jaw is thrust forward, so their head
● appropriately-sized face mask is in the ‘sniffing’ position. Place your thumb and third
● manual ventilation (ambubag™) available and finger on either side of the thyroid cartilage and index
attached to oxygen supply finger on top. Pressure is applied in the sequence back-
● ETT cuff inflated in sterile water to ensure no leaks and wards (towards the spine), upwards (towards the head),
even inflation rightward (towards the patient’s right side). This is
● water-based lubricant of tube and cuff (while main- easier to perform following administration of muscle
taining sterility) relaxants. 29,30
● capnography (chemical CO 2 detectors are often used
in emergency situations) Cuff Management
● ventilator and circuit
● emergency/resuscitation trolley at bedside Endotracheal and tracheostomy tube cuffs prevent airway
● gloves, eye protection contamination by pharyngeal secretions and gastric con-
● drugs (sedative and muscle relaxant) tents and loss of tidal volume during mechanical ventila-
tion. The cuff does not secure the tube in the trachea.
Cuff inflation pressures should be maintained at 20–
30 cmH 2 O. 31,32 Cuff inflation pressures ≤20 cmH 2 O
Practice tip (15 mmHg) are associated with an increased risk of aspi-
ration and a 2.5-fold increase in ventilator-associated
During intubation, know who to call for help, and do not hesi- pneumonia (VAP). Conversely, tracheal wall damage
33
tate to do so. may occur if cuff pressure exceeds the capillary perfusion
pressure in the trachea (27–40 cmH 2 O/20–30 mmHg).