Management of Labor analgesia and CS anesthesia in a parturient with spinal muscular atrophy Type II, severe restrictive lung disease and Harrington rods
Abstract Number: 226
Abstract Type: Case Report/Case Series
Spinal muscular atrophy type 2 (SMAII, Werdnig Hoffmann), a severe inherited neuromuscular disorder characterized by degeneration of anterior horn cells of the spinal cord, presents in infancy and patients rarely survive to adulthood. There are few reported cases of pregnancy and labor management and only 1 detailed report of anesthesia for CS in SMAII 1. We report on the intrapartum anesthesia management of a woman with a molecular confirmation of SMAII.
A 30yo wheelchair-bound G1P0 with severe restrictive lung disease and Harrington rods (HR) from sacrum to mid-thoracic level desired vaginal delivery with induction of labor (IOL) at 38wks. The plan to perform an US-assisted placement of epidural catheter for labor analgesia proved useless, as the usual anatomic landmarks were unidentifiable. After IOL a CSE was attempted at L3-4 in the sitting position. LOR to saline was noted at 5cm but with no return of CSF (Sprotte 25G). Epidural catheter was threaded and tested with Lido2% 3ml+fentanyl 25mcg. There was no sensory level, but patient reported some comfort so PCEA was started (Bup 0.0625%-fentanyl 2mcg/ml: 10ml/h, 5ml q15). Later there were equivocal findings of a unilateral block but PCEA continued to provide comfort. Failed IOL was defined at >72h and CS was called. Testing of epidural catheter with Lido2% 5ml was equivocal for iv toxicity. Attempts at single shot or placement of spinal catheter failed and rapid-sequence GA was induced (PROP 2mg/kg, ROC 0.9mg/kg, SEVO 0.5MAC with N2O/O2, FENTA 2.5mcg/kg after delivery). As anticipated, delayed recovery of muscle tone following non-depolarizing neuromuscular blockade was noted. Patient was admitted to ICU and extubated 12h later. She reported generalized muscular weakness and difficulty swallowing for 1wk. The patient is now planning a 2nd pregnancy.
The request for vaginal delivery prompted the decision of IOL with early neuraxial analgesia rather than an elective CS. Labor analgesia proved to be challenging and a GA was inevitable when a CS was finally called for. Our learning points from this case are:
1) US guidance may not be useful in patients with HR and alternate radiological techniques may be considered when possible (neuraxial block under fluoroscopy)
2) We do not know the effects of SMAII on uterine contractility and success of IOL
3) SMAII causes prolonged muscular blockade after non-depolarizing agents; they should thus be avoided.
1. J Clin Anesth. 2004;16:217-9