Tag Archives: Tips

Cricoid pressure during mask ventilation

While cricoid pressure’s effectiveness at preventing passive regurgitation and aspiration during intubation is disputed, it may be effectively applied during bag-mask ventilation to prevent gastric insufflation of air in both adults and children.

The prevention of gastric inflation–a neglected benefit of cricoid pressure
Anaesth Intensive Care. 1988 May;16(2):139-43

The effect of cricoid pressure on preventing gastric insufflation in infants and children
Anesthesiology. 1993 Apr;78(4):652-6

Paediatric gastric tubes

A child with status epilepticus has been stabilised and intubated and is awaiting admission to the paediatric intensive care unit. You decide to insert a nasogastric tube. The nurse asks the following questions:

1. What size gastric tube would you like?

A general guide is twice the size of the uncuffed tracheal tube.
A four year old for example would usually need a tracheal tube size of 5.0mm internal diameter (age/4 +4), so would need a 10 Fr gastric tube.

2. To what length are you intending to insert it?

A formula based on height of the child can be used, so get your tape measure or length chart out:


For neonates < 2 weeks and children >8 years 4 months a method called NEMU (nose-ear-midxiphoid-umbilicus measurement) may be used.

3. How will you confirm placement?

It is very likely this child will get a post-intubation chest radiograph and the gastric tube tip can be visualised on that. However non-radiological tests should be used and pH testing of the aspirate is recommended, looking for pH<6

Further details on these measurements including positive and negative likelihood ratios of pH testing can be found in the evidence-based guideline from Cincinnati Children’s Hospital

Tying the tracheal tube

After intubation it is critical to securely fasten the tracheal tube so it does not dislodge during transfer. Dedicated devices are available for this although mostly cloth tape is used.

Different knots have been compared although not found be significantly different in terms of security1. One favoured knot, which is easy to learn and to teach, is the lark’s head (also called cow’s hitch)2.

The tape is folded in half so there is a loop at one end and two free ends at the other. The loop is wrapped around the tube and the two free ends are fed through the loop, and then taped around the patient’s head. It has been suggested that this results in the tape gripping the tube over the widest possible area, thereby reducing the potential for slippage and displacement.


larks head knot
larks head knot

1.The insecure airway: a comparison of knots and commercial devices for securing endotracheal tubes
BMC Emerg Med. 2006 May 24;6:7 Open Access

2. A knotty problem resolved
Anaesthesia. 2007 Jun;62(6):637