Sux Apnoea - A Case Study

1. Sux Apnoea- A Case Study Karenne Nielsen Clinical Nurse Specialist West Gippsland Healthcare Group

2. 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

3. 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

4. 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

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

6. “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

7. 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

8. 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 ++

9. Anaesthetic drugs • Midazolam 2mgs IVI • Fentanyl 100µgs IVI • Propofol 200mgs IVI • Suxamethonium100mgs IVI @ 1355 • Nitrous/Oxygen 2:2 • Sevoflurane 2% • Cephazolin 1gm IVI

10. 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

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

12. Management • Urinary catheter • Pressure area care • Calf stimulation • Eye care • Wound/drain care • Nerve stimulator Plan for emergency surgery

13. 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

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

15. 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

16. 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

17. 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

18. The end!! Thankyou very much for your attention.