DEX significantly depressed sinus and atrioventricular nodal function in pediatric patients. Heart rate decreased and arterial blood pressure increased during administration of DEX. The use of DEX may not be desirable during electrophysiology study and may be associated with adverse effects in patients at risk for bradycardia or atrioventricular nodal block.

The technical and medical management of small infants requiring orthotopic liver transplantation remains a challenge. The present study examined 117 orthotopic liver transplantations performed in 101 infants from <1 to 23 months of age between March 1988 and February 1995 to determine factors that influence patient and graft outcome. Factors analyzed included etiology of liver disease, recipient and donor age and weight, United Network for Organ Sharing (UNOS) status, retransplantation, ABO-compatibility, full-size (FS) versus reduced-size grafts, vascular thrombosis (VT), including hepatic artery and portal vein (PVT), and the presence of lymphoproliferative disease (LPD). UNOS status 1, fulminant hepatic failure, and the development of Epstein-Barr virus-associated LPD were each associated with 10-20% lower patient and graft survival rates. Of 101 infants, 11 (11%) developed LPD with an associated 36% mortality. VT occurred in 10 (9 hepatic artery and 1 portal vein) of 117 orthotopic liver transplantations (9%), all less than 1 year of age, and was associated with significantly poorer 1-year (50% vs. 85% no VT, P<0.01) and 5-year patient survival rates (50% vs. 83% no VT, P<0.01). One-year graft survival rates for FS grafts in recipients <12 months versus 12-23 months were 67% vs. 94% (P<0.01); the patient survival rate was also significantly lower in FS graft recipients <12 months (76% vs. 100%, P<0.05). Recipients <5 months of age had the worst survival rates: 1-year and 5-year patient survival rates were 65% and 46% for recipients 0-4 months (n=17) versus 82% and 82% for recipients 5-11 months (n=56), and 93% and 93% for recipients age 12-23 months (n=28; P<0.05). In summary, factors associated with reduced survival rates include recipient age <5 months, recipient age <12 months who received FS grafts, development of VT and donor weight <6 kg. There was a trend for UNOS status 1, fulminant hepatic failure, and presence of LPD to be associated with reduced survival rates.

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Administering anaesthesia to a child with an anterior mediastinal mass may lead to respiratory or circulatory collapse, even in those without symptoms. Institutions should have algorithms to manage children with mediastinal masses. Preoperative evaluations should include computed tomography, echocardiography and flow-volume studies. Anaesthesia may be induced with inhalation agents and maintained with spontaneous respiration via facemask or laryngeal mask airway. Alternatively, positive-pressure ventilation may be used, including tracheal intubation without muscle relaxants. Rigid bronchoscopy may be life-saving in the event of tracheal or bronchial collapse under anaesthesia.

No abstract

During the past decade, the use of video-assisted thoracoscopic surgery (VATS) has dramatically increased in children as well as adults. Although VATS can be performed while both lungs are being ventilated, single-lung ventilation (SLV) is desirable during VATS. In addition, anaesthesiologists are performing (and paediatric surgeons are requesting) SLV more frequently for open thoracotomies in infants and children.

Background The lack of methadone pharmacokinetic data in children and neonates restrains dosing to achieve the target concentration in these populations. A minimum effective analgesic concentration of methadone in opioid naïve adults is 0.058 mg.L−1, while no withdrawal symptoms were observed in neonates suffering opioid withdrawal if plasma concentrations of methadone were above 0.06 mg.L−1. The racemate of methadone which is commonly used in pediatric and anaesthetic care is metabolized to EDDP (2-ethylidine-1,5-dimethyl-3,3-diphenylpyrrolidine) and EMDP (2-ethyl-5-methyl-3,3-diphenylpyrroline). Methods Data from 4 studies (age 33 weeks PMA-15 years) were pooled (n=56) for compartment analysis using nonlinear mixed effects modeling. Parameter estimates were standardized to a 70 kg person using an allometric model approach. Investigation was made of the racemate and metabolite (EDDP and EMDP) dispositions. In addition, neonatal data (n=7) allowed further study of R and S enantiomer pharmacokinetics. Results A three-compartment linear disposition model best described the observed time-concentration profiles with additional compartments for metabolites. Population parameter estimates (between subject variability) were central volume (V1) 21.5 (29%) L.70kg−1, peripheral volumes of distribution V2 75.1 (23%) L.70kg−1, V3 484 (8%) L.70kg−1, clearance (CL) 9.45 (11%) L.h−1.70kg−1 and inter-compartment clearances Q2 325 (21%) L.h−1.70kg−1, Q3 136 (14%) L.h−1.70kg−1. EDDP formation clearance was 9.1 (11%) L.h−1.70kg−1, formation clearance of EMDP from EDDP 7.4 (63%) L.h−1.70kg−1, elimination clearance of EDDP was 40.9 (26%) L.h−1.70kg−1, and the rate constant for intermediate compartments 2.17 (43%) /h. Conclusions Current pharmacokinetic parameter estimates in children and neonates are similar to those reported in adults. There was no clearance maturation with age. Neonatal enantiomer clearances were similar to those described in adults. A regimen of 0.2 mg.kg−1 per 8 h in neonates achieves a target concentration of 0.06 mg.L−1 within 36 h. Infusion, rather than intermittent dosing should be considered if this target is to be achieved in older children after cardiac surgery.

Despite its favorable respiratory profile, dexmedetomidine may cause deleterious cardiovascular effects. Close monitoring of circulatory dynamics and judicious titration is recommended. Further studies are needed to better define adverse effects following long-term infusions as well as in special populations such as pre-term infants.