title: Oral contrast for abdominal computed tomography in children: the effects on gastric fluid volume.
abstract: BACKGROUND
  Oral enteric contrast medium (ECM) is frequently administered to achieve visualization of the gastrointestinal tract during abdominal evaluation with computed tomography (CT). Administering oral ECM less than 2 hours before sedation/anesthesia violates the nothing-by-mouth guidelines and in theory may increase the risk of aspiration pneumonia. In this study we measured the residual gastric fluid when using a protocol in which ECM is administered up to 1 hour before anesthesia/sedation. We hypothesized that patients receiving ECM 1 hour before anesthesia/sedation would have residual gastric fluid volume (GFV) >0.4 mL/kg.
  
  
  METHODS
  Anesthesia and radiology reports, CT images, and department incident reports were reviewed between January 2005 and June 2009 for all patients who required sedation/anesthesia for abdominal CT. For each patient, the volume of contrast or stomach fluid was calculated using a region of interest outlining the stomach portion containing high-attenuation fluid and low-attenuation of other gastric contents. Information obtained from anesthesia/sedation reports included demographic characteristics, presenting pathology, drugs used for anesthesia/sedation induction and maintenance, airway interventions, method for securing endotracheal tube, and complications related to ECM administration, including oxygen desaturation, vomiting, coughing, bronchospasm, laryngospasm, and aspiration.
  
  
  RESULTS
  We identified 365 patients (mean age = 32 months; range = 0.66 to 211.10 months) who received oral/IV contrast material before anesthesia/sedation for abdominal CT and 47 patients (mean age = 52 months; range = 0.63 to 215.84 months) who received only IV contrast material and followed the traditional fast. For those who received oral contrast, the mean contrast volume administered was 18.10 mL/kg (range = 1.5 to 82.76 mL/kg). The median GVF 1 hour after completing the oral contrast was significantly higher than that in patients who received only IV contrast (0.38 mL/kg vs. 0.15 mL/kg, P = 0.0049). GFV exceeded 0.4 mL/kg in 189 patients (178 of 365 [49%] in the oral contrast group vs. 11 of 47 [23%] in the IV contrast group) (χ(2) = 10.7874, P = 0.0010). Among those who received oral contrast, 207 patients had general anesthesia and 158 patients had deep sedation. Two cases of vomiting were reported in the general anesthesia group with no evidence of pulmonary aspiration identified.
  
  
  CONCLUSIONS
  For children receiving an abdominal CT, the residual GFV exceeded 0.4 mL/kg in 49% (178/365) of those who received oral ECM up to 1 hour before anesthesia/sedation in comparison with 23% (11/47) of those who received IV-only contrast.
authors.affiliation: Department of Anesthesiology, Tehran University Children's Hospital Medical Center, Tehran, Iran. mohamed.mahmoud@cchmc.org
authors.forename: Mohamed
authors.initials: M
authors.lastname: Mahmoud
authors.forename: John
authors.initials: J
authors.lastname: McAuliffe
authors.forename: Hwa-Young
authors.initials: HY
authors.lastname: Kim
authors.forename: Pragnyadipta
authors.initials: P
authors.lastname: Mishra
authors.forename: Shelia
authors.initials: S
authors.lastname: Salisbury
authors.forename: Beverly
authors.initials: B
authors.lastname: Schnell
authors.forename: Patricia
authors.initials: P
authors.lastname: Hirsch
authors.forename: Shahriar
authors.initials: S
authors.lastname: Arbabi
authors.forename: Lane F
authors.initials: LF
authors.lastname: Donnelly
mesh_terms: D000284:Administration, Oral; D000293:Adolescent; D000768:Anesthesia, General / Q000009:adverse effects; D018681:Anesthetics, General / Q000008:administration & dosage / Q000009:adverse effects; D016009:Chi-Square Distribution; D002648:Child; D002675:Child, Preschool; D003287:Contrast Media / Q000008:administration & dosage* / Q000009:adverse effects; D054810:Deep Sedation / Q000009:adverse effects; D004334:Drug Administration Schedule; D005215:Fasting; D005260:Female; D005750:Gastric Juice; D006801:Humans; D006993:Hypnotics and Sedatives / Q000008:administration & dosage / Q000009:adverse effects; D007223:Infant; D007275:Injections, Intravenous; D007472:Iohexol / Q000008:administration & dosage* / Q000009:adverse effects; D008297:Male; D009820:Ohio; D011860:Radiography, Abdominal / Q000379:methods*; D053120:Respiratory Aspiration / Q000209:etiology; D012189:Retrospective Studies; D018570:Risk Assessment; D013997:Time Factors; D014057:Tomography, X-Ray Computed; D014283:Triiodobenzoic Acids / Q000008:administration & dosage* / Q000009:adverse effects; D014839:Vomiting / Q000209:etiology
chemical_list: D018681:Anesthetics, General; D003287:Contrast Media; D006993:Hypnotics and Sedatives; D014283:Triiodobenzoic Acids; D007472:Iohexol; C054871:ioversol