Remifentanil to Facilitate High-Resolution Computed Tomography Imaging of the Chest or Magnetic Resonance Imaging in Infants

Abstract

High-resolution computed tomography (CT) imaging or magnetic resonance (MR) imaging may require brief periods of apnea for image acquisition. In adults, this may be done by voluntary breath holding. In infants and children, such studies are generally performed under general anesthesia using a laryngeal mask airway with maintenance of spontaneous ventilation. We report a technique using the short-acting synthetic opioid, remifentanil, as part of an anesthetic technique to provide brief periods of apnea and the rapid resumption of spontaneous ventilation. The study cohort included 12 patients (8 for high-resolution CT imaging and 4 for abdominal MR imaging) who ranged in age from 6 to 16 months. General anesthesia with spontaneous ventilation was induced with sevoflurane in air and oxygen. When apnea was required, remifentanil (3 microg/kg) was administered. Apnea occurred within 30-60 seconds following the bolus dose of remifentanil (42 +/- 8 seconds). The duration of apnea varied from 3 to 8 minutes (4.8 +/- 1.5 minutes). Following the administration of remifentanil, there was a decrease in heart rate (HR) from 127 +/- 7 to a low of 108 +/- 9 beats per minute (P < 0.0001). Systolic blood pressure (sBP) decreased from 84 +/- 6 mm Hg to 78 +/- 5 mm Hg (P = 0.0071). One patient received a fluid bolus (10 mL/kg) for a sBP of 56 mm Hg. No other adverse effects were noted. This technique facilitated anesthetic care by allowing the use of a laryngeal mask airway (LMA) for both the radiologic imaging as well as bronchoscopy which was performed after the radiologic imaging. The use of a bolus dose of remifentanil provided a brief period of apnea for the acquisition of the radiologic images.