///2009 Abstract Details
2009 Abstract Details2019-08-03T15:55:31-05:00

Unexpectedly low anesthetic dose requirements for cesarean delivery and post-operative hypoxia in a patient with Achondroplasia

Abstract Number: 106
Abstract Type: Case Report/Case Series

Andrea J Fuller M.D.1 ; Matthew Roberts M.B.2; Matthew Palcso M.D.3; Joy L Hawkins M.D.4

Introduction: Dwarfism is defined as an adult height of less than 147 cm. The most common form is Achondroplasia, affecting approximately 1 in 15,000 people. Regional anesthesia for cesarean delivery is possible in these patients but effective doses are highly variable.

Case Report: A G1P0 patient at 35 weeks gestation with achondroplasia presented to the OB service at 2am with spontaneous rupture of membranes. Her height and weight were 119cm and 50kg. She had a past medical history significant for tracheostomy at age 1 for obstructive sleep apnea (OSA), which resolved in early childhood. An echocardiogram at 17 weeks gestation was normal. She had a large tongue, small chin, and a Mallampati Class II airway. Cesarean delivery was necessary due to cephalopelvic disproportion. Epidural catheter placement was performed in the sitting position at L2-3. Loss of resistance was obtained with saline and an 18GT needle. There was no evidence of intravascular or intrathecal catheter placement. After negative aspiration, 2ml of 1.5% lidocaine with 1:200,000 epinephrine was administered as a test dose. The patient developed a complete motor block and sensory level to T4. A male infant was delivered. Towards the end of surgery she began to experience some pain and was given fentanyl 25mcg and 0.5ml of bupivicaine 0.5% through the catheter to good effect. Postoperatively, she was given hydromorphone IV PCA on a demand basis. Neuraxial morphine was not given due to the uncertainty of the appropriate dosage. She received 0.8mg of IV hydromorphone over 2 hours and subsequently developed extreme hypoxia and somnolence. CT angiogram showed a pericardial effusion and a pleural-based opacity at the right costophrenic recess suggestive of pneumonia or aspiration pneumonitis. EKG showed right axis deviation. Echocardiogram revealed mild pulmonary hypertension. Episodes of airway obstruction and apnea were observed while she was sleeping. The PCA was discontinued and CPAP was administered. Her hypoxia resolved and she was discharged on post-operative day 4.

Discussion: Regional anesthesia is an established technique for cesarean section in patients with Achondroplasia. Many of these patients have spinal stenosis at various levels, rendering aspiration for CSF negative when the catheter is in fact intrathecal. This may have been the case with our patient. This report highlights the importance of a catheter-based technique and incremental dosing in patients with dwarfism. Furthermore, OSA can be a significant co-morbidity. Careful preoperative evaluation including obstructive symptoms, presence of OSA, and any end-organ damage should be established. Vigilant postoperative monitoring for hypoxia and obstruction is imperative for the best possible outcome.

(1) Obstetric Anesthesia and Uncommon Disorders; 2008,pp. 115-28. (2) IJOA 1993;2(2):96-7.

SOAP 2009