Safety and performance of TCI pumps in a magnetic resonance imaging environment.

Target controlled infusion (TCI) devices can be associated with significant safety concerns when used during magnetic resonance imaging (MRI). We tested the safety and compatibility of newer TCI systems in a 3-Tesla MRI environment. Two Asena PK and two Agilia TCI pumps were used to administer TCI propofol (at target blood concentrations of 0.5 and 6.0 µg.ml⁻¹) using the Marsh model under magnetic fields of up to 50 G with a T2-weighted sequence. We assessed the devices for projectile risk, accuracy of drug delivery, alarm function and effects on MR image quality. Both devices did not demonstrate any significant deflection at the tested field strengths, and performed within acceptable limits (cumulative error in total delivered volume < 3%; maximum 10-min interval error < 10%). The Asena pump caused minor artefacts on MR images. The TCI pumps tested perform well and safely implement pharmacokinetic software in a high magnetic field.

Facial thermography is a sensitive and specific method for assessing food challenge outcome.

BACKGROUND: Oral challenge is widely used for diagnosing food allergy but variable interpretation of subjective symptoms may cause error. Facial thermography was evaluated as a novel, objective and sensitive indicator of challenge outcome. METHODS: A total of 24 children with a history of egg allergy underwent oral challenge, which were scored positive when objective symptoms occurred or negative after all doses were consumed without reaction. Facial temperatures were recorded at baseline and 10-min intervals. The difference between mean and baseline temperature (DeltaT), maximum DeltaT during challenge (DeltaT(max)) and area under curve of DeltaT against time (DeltaTAUC) were calculated for predefined nasal, oral and forehead areas, and related to objective challenge outcome. RESULTS: There were 13 positive and 11 negative challenges. Median nasal DeltaTAUC and DeltaT(max) were greater in positive compared with negative challenges (231- and 5-fold, respectively; P < 0.05). In positive challenges, nasal temperatures showed an early transient rise at 20 min, preceding objective symptoms at median 67 min. There was a sustained temperature increase from 60 min, which was reduced by antihistamines. A cut-off for nasal DeltaT(max) of 0.8 degrees C occurring within 20 min of the start of the challenge predicted outcome with 91% sensitivity (positive predictive value [PPV] 100%) and 100% specificity (negative predictive value [NPV] 93%). Subjective symptoms occurred in four of 13 positive and three of 11 negative challenges. CONCLUSIONS: Facial thermography consistently detects a significant early rise in nasal temperature during positive compared with negative food challenges, which is evident before objective symptoms occur. Thermography may therefore provide a sensitive method to determine outcome of food challenges and investigate the pathophysiology of food allergic reactions.

Saddle arterial embolus in a patient with Down syndrome.

We report acute thromboembolic events in a 14-year-old boy with Down syndrome and repaired atrioventricular septal defect. He presented with sudden onset of bilateral lower limb ischemia. Transesophageal echocardiography detected a thrombus in the right atrium. An arterial saddle embolus was removed following bilateral iliac embolectomy. Despite anticoagulation, he presented again with sudden bilateral lower limb ischemia and respiratory distress. Multiple pulmonary emboli and a thrombus in the right atrium were noted on imaging studies. An arterial embolus was removed from the abdominal aorta at the bifurcation. To our knowledge, this is the first report of a child or adolescent with a repaired congenital heart lesion and arterial embolism requiring embolectomy. This association and possible etiological factors are discussed.