Dexmedetomidine for Awake Fiberoptic Intubation in a Parturient With Spinal Muscular Atrophy Type III for Cesarean Delivery

Abstract

S pinal muscular atrophy (SMA), an inherited motor neuron disease, causes progressive degeneration of the spinal cord anterior horn cells and leads to muscle atrophy, respiratory muscle insufficiency, and scoliosis. Although the disease is rare in parturients, when present, it causes multiple problems, including airway difficulties, respiratory compromise, and spinal abnormalities. Dexmedetomidine has been used to facilitate awake fiberoptic intubation but the effect of the drug in parturients is less known. This case report describes the successful use of dexmedetomidine to facilitate fiberoptic intubation in a parturient with SMA before cesarean delivery.The 35-year-old patient with SMA type III presented at 35 weeks of gestation for urgent cesarean section after premature spontaneous rupture of membranes. She had anemia, asthma, and severe restrictive lung disease and had previously undergone a thoracosacral spinal fusion. She had a Mallampati class 4 airway, with a 12-mm mouth opening, limited cervical spine movement, complete airway obstruction when her head was turned to the left, and severe scoliosis. She consented to awake fiberoptic intubation using dexmedetomidine for sedation to avoid benzodiazepines and opioids before delivery. She had normal cardiac function and an ejection fraction of 70%. Pulmonary function tests confirmed severe restrictive lung disease and a severe decrease in diffusing capacity. She was placed in the right lateral position with her head turned to the right to obtain maximal airway patency. Standard monitors and an intra-arterial catheter were used along with supplemental oxygen. Intravenous dexmedetomidine 1 mg/kg was administered over 10 minutes, followed by an infusion of 1 mg/kg/h. She became anxious during the initial intubation attempt so a bolus of dexmedetomidine, 0.5 mg/kg, was given. She was successfully intubated on the third attempt. A total of 1.84 mg/kg dexmedetomidine was administered over 38 minutes. The patient was hypertensive before initiation of dexmedetomidine and had normal to elevated blood pressures during the intubation attempts. She did become hypotensive after induction of general anesthesia, which was treated successfully with two 5-mg doses of intravenous ephedrine. Intermittent fetal heart tones were normal. Dexmedetomidine was discontinued once the endotracheal tube was secured and general anesthesia was induced with sevoflurane. A right internal jugular central venous catheter was placed under ultrasound guidance, but was technically difficult due to contractures and lack of mobility in the cervical spine. Rocuronium, 0.5 mg/kg, was administered to aid surgeons in positioning the patient to maximize exposure of the lower abdomen. The infant was delivered 4 minutes after skin incision and 68 minutes after the dexmedetomidine infusion was halted. At the time of delivery, the maternal central venous, umbilical arterial, and umbilical venous dexmedetomidine concentrations were 710, 540, and 543 pg/mL, respectively. The neonate's 1-minute and 5-minute A...

Comparison of Intrathecal Dexmedetomidine with Morphine as Adjuvants in Cesarean Sections

“…Previous studies have also shown that intravenous dexmedetomidine has no adverse effect on parturients and neonates, [31][32][33] similar results were also obtained in the present study. The results showed no difference in the Apgar score, heart rate or NACS compared with the control group.…”

Intrathecal Dexmedetomidine Alleviates Shivering during Cesarean Delivery under Spinal Anesthesia

“…[32][33][34][35] Recently, many studies have demonstrated that intrathecal ropivacaine or bupivacaine-dexmedetomidine may increase the duration and efficacy of analgesia and decrease postoperative analgesic use, without notable adverse effects. 11,12,36) The use of dexmedetomidine as an adjuvant to bupivacaine for covering Cesarean delivery provided better intra-operative analgesia and did not affect Apgar scores or caused any noticeable side effects. 13,28) The intrathecal doses of dexmedetomidine used in our study were based on previous human studies wherein no neurotoxic effects were documented at these doses.…”

“…dexmedetomidine to facilitate Cesarean delivery in the parturient population has been reported in several case reports, including in a woman with primary pulmonary hypertension, 10) and in another with spinal muscular atrophy. 11) On the contrary, many studies showed that dexmedetomidine was an effective adjuvant to intrathecal local anesthetics for prolonging the duration of analgesia for lower abdominal surgeries, lower limb surgeries and Cesarean delivery. 12,13) However, the preventive effect of intrathecal dexmedetomidine on shivering has not been evaluated.…”

Conscious sedation for awake fibreoptic intubation: a review of the literature

“…The antisialagogue and moderate analgesic properties of dexmedetomidine have been cited as other advantages. 41,42 We identified 19 articles, five RCTs 13,29,43-45 and 14 case reports and case series [46][47][48][49][50][51][52][53][54][55][56][57][58][59] describing the use of dexmedetomidine for AFOI, usually as the sole agent but occasionally in combination with midazolam 43 or ketamine. 60 Although a TCI system for dexmedetomidine has been described for awake intubation, 47 it is generally administered as a slow bolus (usually 1 lgÁkg -1 over 10-20 min) to avoid peak-dose hypertension (which may exacerbate a bradycardia-related fall in cardiac output) followed by an infusion (usually of 0.1-0.7 lgÁkg…”

“…51 The safe respiratory profile of dexmedetomidine has been borne out by reports describing its use in patients with raised intracranial pressure at risk from hypoventilation 52 and in obstetrics with minimal adverse neonatal sequelae. 53,54 The ability to produce a deeply sedated state while maintaining a safe degree of respiratory function has also allowed it to be successfully used in children and uncooperative adults. 55,56 Nevertheless, the real advantage of a sedative that spares respiratory function may become apparent when the clinician is presented with patients already in or at risk of airway obstruction and/or respiratory failure; yet (not surprisingly), to date, there have been only limited case series dealing with such cases.…”