Sux Apnoea- A Case Study

Karenne Nielsen

Clinical Nurse Specialist

West Gippsland Healthcare Group

Suxamethonium Chloride “Sux” “Scoline”

Short acting muscle relaxant Allows rapid intubation of trachea &

provides short periods of neuromuscular

blockade Main uses - difficult intubation

- emergency conditions

- brief procedures

Suxamethonium “Sux”

Dose = 1-2 mgs/kg IVI or IMI Rapid onset of muscle relaxation

- fasciculation 30-60 seconds Short duration of 5-10 minutes

- apnoea lasts ≈ 5 mins

- paralysis recovery another 5 mins

Suxamethonium – “Sux”

Metabolised by plasma cholinesterase

- an enzyme produced in the liver & present in the blood

Plasma cholinesterase is usually present in sufficient concentration to give a half-life of approx. 4 mins

No reversal agent

Side effects

Cardiovascular – bradycardia Hyperkalaemia Raised intraocular/pressure Allergic reaction → Anaphylaxis Malignant hyperthermia Muscle pains- calf & chest Prolonged muscle paralysis

“Sux apnoea”

Rare condition in 4-6% population Patients with abnormal plasma

cholinesterase are incapable of metabolising suxamethonium resulting in prolonged muscle paralysis and apnoea.

Inherited - often normal levels but abnormal plasma cholinesterase (up to 8hrs or more)

Acquired – lower levels of normal plasma cholinesterase

Case study

55 year old Female No significant medical/family history Nil current medications Non smoker Surgical & Anaesthetic history

- Varicose Vein Ligation 2002

- GA no muscle relaxants

Pre-Anaesthetic Assessment

Weight: 77.5 kgs / Height: 156cm Reflux lying flat in bed “High risk of gastric reflux” Undershot jaw – Airway Grade III “? Difficult intubation” ASA score 2 Anxious patient ++

Anaesthetic drugs

Midazolam 2mgs IVI Fentanyl 100µgs IVI Propofol 200mgs IVI Suxamethonium 100mgs IVI @ 1355 Nitrous/Oxygen 2:2 Sevoflurane 2% Cephazolin 1gm IVI

Anaesthetic/Operation

Ventral Hernia Repair with Mesh - surgery straightforward = 1hr No muscle movement noted

throughout the operation – end time 1hr & 10 mins after “sux”given

Sux apnoea or another diagnosis ? Assumption of Sux apnoea confirmed

by nerve stimulation

Management

Anaesthesia maintained - important to be patient - keep asleep and unaware Continuous monitoring Entropy monitoring Fluid and electrolyte balance Temperature BSL

Management

Urinary catheter Pressure area care Calf stimulation Eye care Wound/drain care Nerve stimulator

Plan for emergency surgery

Management

Relatives kept informed & to visit

- truthful explanation of condition

- reassure safe & waiting to wake

- ? Fresh Frozen Plasma Started to swallow @ 6½hrs Extubated 30 mins later Total time = 7 hours

Recovery

Drowsy Co-operative and talking No recollection Required narcotic analgesia Very dry mouth Puffy eyes Husband to visit

Post-op period

Hypokalaemia post op day 1& 2

- Potassium replaced IVI & orally Febrile post op day 2

- CXR ? pneumonia

- oral antibiotics Erythema of wound day 3 Discharged post op day 5

Follow up for Sux Apnoea

Review 1 month post-op Debriefing with family present - Sux Apnoea episode - Importance of alerting staff with

future anaesthetics - Pseudocholinesterase typing & Phenotype differentiation Patient and family tested

Follow up testing

Normal Dibucaine = over 70% Homozygous normal = (6.0-15.6) “K” – Dibucaine Inhibition = 15%

confirming susceptibility to “Sux” Genotype testing unavailable but

length of apnoea suggests rare clinical variant

Children 4/6 tested – all normal levels

The end!!

Thankyou very much for your attention.