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Deficits in executive functions related to spatial working memory do occur in children with ADHD, although the magnitude of these deficits is not related to the child's age or the level of ADHD symptoms. These deficits were not present in the current sample of children who were receiving psychostimulant medication.

Small single-institutional studies performed prior to the introduction of organ allocation using the Model for End-Stage Liver Disease (MELD) suggest that early airway extubation of liver transplant recipients is a safe practice. We designed a multicenter study to examine adverse events associated with early extubation in patients selected for liver transplantation using MELD score. A total of 7 institutions extubated all patients meeting study criteria and reported adverse events that occurred within 72 hours following surgery. Adverse events were uncommon: occurring in only 7.7% of 391 patients studied. Most adverse events were pulmonary or surgically related. Pulmonary complications were usually minor, requiring only an increase in ambient oxygen concentration. The majority of surgical adverse events required additional surgery. Analysis of a limited set of perioperative variables suggest that blood transfusions and technical factors were associated with an increased risk of adverse events. In conclusion, while early extubation appears to be safe under specified circumstances, there are performance differences between institutions that remain to be explained. Liver Transpl 13:1557Transpl 13: -1563Transpl 13: , 2007

While impairment in spatial cognition is consistent with previous studies of OCD, its significance for brain-behaviour models of OCD is unclear. However, the finding of abnormal olfactory identification in patients with OCD is consistent with the hypothesis that there is a disruption to processing at the level of the OFC in the disorder.

Cardiac arrest associated with reperfusion of the liver allograft in a euvolemic patient is a rare but potentially devastating event. There are few case series describing experience with this complication and no published management protocols guiding treatment. This article is a retrospective case series of patients experiencing post-reperfusion intraoperative cardiac arrest between 1997 and 2011. Among 1581 liver transplants, 16 (1%) patients experienced post-reperfusion cardiac arrest. Among patients with intraoperative arrests, 14 (88%) patients required open cardiac massage. Seven (44%) were placed on cardiopulmonary bypass (CPB) when cardiac activity failed to adequately recover. Placement on CPB reversed cardiac pump failure and established a perfusing rhythm in six of seven (86%) recipients, leading to one of seven (14%) intraoperative mortality. Recovery of myocardial function was associated with low early survival with only 3/7 (43%) patients who underwent CPB surviving until discharge. Among all patients who survived the perioperative period, one-yr survival was 70% (N = 7), and five-yr survival was 50% (N = 5). Cardiac arrest during liver transplantation is associated with a poor prognosis during the perioperative period. In patients who do not recover cardiac activity after standard resuscitative measures, progression to physiologic support with systemic anticoagulation and CPB may allow correction of electrolyte derangements, maintenance of cerebral perfusion, and myocardial recovery.

Seeds containing radioactive Ytterbium-169 (169Yb) have recently been manufactured for possible application to brachytherapy. Ytterbium-169 emits photons with an average energy of 93 keV (excluding energies less than 10 keV), and decays with a half-life of 32 days. Analytic and Monte Carlo computations have been used to predict physical quantities useful in treatment planning and radiation protection. Analytic calculations based on the primary photon spectrum of 169Yb (excluding energies less than 10 keV) yield an air-kerma rate constant of 0.0427 cGy cm2 h-1 MBq-1, and an exposure rate constant of 1.80 R cm2 mCi-1 h-1 for this radionuclide. Calculated fmed factors are 0.922 cGy/R for soft tissue and 2.12 cGy/R for bone. The first half-value layer in lead is 0.2 mm; the first tenth-value layer is 1.6 mm. Using Monte Carlo simulations, the relative dose distributions around 169Yb seeds (Amersham, prototypes 4 and 5) are provided, and are then compared with those around an 125I seed (3M model 6702). The 169Yb seeds produce more isotropic dose distributions, and for permanent implants, can deliver it at a greater initial dose rate. A value of 1.19 cm-2 was also calculated for the specific dose constant D0, a value which is applicable to both seed types. Radiation protection is not as easily achieved for permanent implants with 169Yb because of the higher energy emissions (vs 125I). However, for temporary implants, Ytterbium-169 may prove to be a useful substitute for 192Ir or 137Cs because of its relatively lower energy emissions. It is concluded that 169Yb merits further investigation, including dosimetry, radiobiological, and clinical studies.

Improved executive function may be a marker of psychostimulant medication effect in children with ADHD-CT treated in the longer term. This improvement may not correlate with that of the ADHD-CT symptoms. Longitudinal studies are required.