GUIDELINES

P1000580

Anaesthetic protocols have developed since this document from 2006, however this offers some perspective and will be updated.

SUGGESTED ANAESTHETIC PROTOCOL FOR EAR CAMPS

David Hill, 2006

These notes are intended as guidance for Anaesthetists who are confronted with Ear Camp conditions for the first time. There may be better techniques, but these have been developed over a number of camps and found to work. Because of the limited equipment (draw-over with Oxford Bellows and simple vapourisers for Halothane & Trilene) general anaesthesia is avoided at almost any cost.

SUGGESTED TECHNIQUE

1. An i.v. cannula is sited in the hand/arm opposite the operated ear.

2. For adults (& pro rata for children) Pentazocine 30mg + Diazepam 5 mg given, mixed in 2 ml syringe. The peak effect seems to be about 15-20 mins, so antibiotics are then given.

3. For adults (& pro rata for children) i.v. Gentamicin 160 mg (recently increased from a 80 mg, which seemed adequate) + Ampicillin 500 mg.

4. For small or anxious children (as young as 6 years have been done) we recently have given Ketamine 1-2 mg per kg to cover the painful injection of Local.

5. A mixture of about 7-8 ml 2% Lignocaine with 1:80,000 Adrenalin (we have recently reverted to 1:80,000 from 1:200,000) + 2-3 ml 0.5% Bupivacaine in a 10 ml syringe & a 27G 1 ½ in needle is used.

6. Starting behind the top of the pinna infiltrate fanwise the temporalis fascia (for donor graft), then down front of the ear for the auricular branch of the auriculo-temporal nerve (Mandibular V), supplying the anterior part of the auricle & skin of temple. It is also blocked in front of the tragus, posterior to the temporo-mandibular joint. Although it arises deep in the mandibular fossa, it becomes superficial, & if blocked deep, the facial nerve will also be blocked.

7. From the original injection site infiltrate behind the pinna in the usual line of incision for post-aural approach. This will also block the greater auricular nerve (C3) supplying the skin of the mastoid & both sides of the auricle, and the auricular branch of X. An injection at the anterior border of the mastoid process will block the branch supplying the surface of the mastoid. (It is said that the bone of the mastoid has no sensory supply).

8. With the tip of a finger in the external auditory meatus inject from a point about midway behind the pinna towards the meatus, but not into it.

9. The intra-aural injections are made in the quadrants - anterior for V, posterior for C3, superior for VII, and inferior for X. The injection must be just beneath the skin; it is tight and painful as the local spreads down to the drum. As a rule, if you can inject, it is probably in the wrong place; if you cannot, it is probably in the right place!

10. A difficult situation, particularly with children, is restlessness, especially if accompanied by some pain. We have latterly reverted to using small doses (or an infusion) of Ketamine to cover this. There is always the possibility of further disorientation, but it seems to be less of a problem after the Pentazocine /Diazepam mixture.



KETAMINE INFUSION
2006
Charlie Collins Consultant Anaesthetist

A. EQUIPMENT
1. Have ambu bag, correct size airway, sucker, oxygen, etc. ready
2. Add Ketamine to bottle of IV Dex/DNS/NS at concentrate 1mg/ml. I.e. to 500 ml bottle add 500 mg Ketamine i.e. 10mls of 50 mg/ml. Cover bottle.

NB Double Strength = 2mg/1ml i.e. 20 mls in 500 ml

B. PATIENT

1. Starved?
2. Check BP if possible
3. Secure good IV line
4. Pray for patient’s safety

PATIENT’S WEIGHT IN NEPAL
Child: 2mgm x age + 4 kg unless fat or very thin!
Adult female: 40-50 kg.
Adult male: 50-60 kg.

C. TECHNIQUE

1. Give IV ATROPINE 20 microg. (0.02) per kg. Max 0.6 mg in adult

2. Give IV DIAZEPAM 0.1 mg per kg.
e.g. Adult female: 7.5 mg
- Adult male: 10mg
- Child: approx 3-5 mg.
- Small child by weight
- Give ½ claculated dose slowly
- Wait 2 mins.
- Give 2nd ½ calculated dose slowly

3. Give IV KETAMINE 2mg/kg
- e. g. Adult female = 100 mg
- Adult male = 125 mg
- Child by weight
- Small child : Dilute Ketamine
- 1 ml of 50mgm/ml + 4 mls water = 10mg/ml

Give slowly over 2-3 mins.

4. Attach drip

Run at 1-2 ml per min in adult i.e. 20 to 40 drops per minute.
- 1 ml per min in child i.e. 20 drops per minute
- < 0.5 ml per min in small child i.e. < 10 drops per minute
- NB Double Strength
- 0.5-1 ml per min in adult i.e. 10-20 drops per min
- 0.5 ml per min in child i.e. 10 drops per minute
- < 0.25 ml per min in small child i.e. < 5 drops per min.

If patient is wakeful turn drip fast for 1 minute

5. Monitor patient

- Is airway ok? Use Collin’s respirometer (whisp of cotton wool taped to tip of nose!)
- Tape stethoscope to trache and listen
- Pulse monitor and check by hand
- Check BP if possible