Relationship between dexmedetomidine dose and plasma dexmedetomidine concentration in critically ill infants: a prospective observational cohort study / 대한마취과학회지

BACKGROUND: Dexmedetomidine is a highly selective central α₂-agonist used as a sedative in pediatric intensive care unit (PICU). However, little is known about the relationship between dexmedetomidine dose and its plasma concentration during long-term infusion. We have previously demonstrated that the sedative plasma dexmedetomidine concentration is moderately correlated with the administered dose in adults (r = 0.653, P = 0.001). We hypothesized that there would be a similar relationship between the sedative dexmedetomidine concentration and administered dose in infants. METHODS: All patients admitted to the PICU at Nagoya City University Hospital, Japan, between November 2012 and March 2013 were eligible for inclusion in the study. Plasma dexmedetomidine concentration was measured by ultra-performance liquid chromatography coupled with tandem mass spectrometry. RESULTS: We measured the plasma dexmedetomidine concentration in 203 samples from 45 patients. Of these, 96 samples collected from 27 patients < 2 years old were included in this study. All patients received dexmedetomidine at 0.12–1.40 µg/kg/h. The median administration duration was 87.6 hours (range: 6–540 hours). Plasma dexmedetomidine concentration ranged from 0.07 to 3.17 ng/ml. Plasma dexmedetomidine concentration was not correlated with the administered dose (r = 0.273, P = 0.007). The approximate linear equation was y = 0.690x + 0.423. CONCLUSIONS: In infants, plasma dexmedetomidine concentration did not exhibit any correlation with administered dose, which is not a reliable means of obtaining optimal plasma concentration.

CartoMerge using SoundStar Catheter and Time Force Integral-Based Ablation for Atrial Fibrillation

Catheter ablation for atrial fibrillation is based on pulmonary vein (PV) isolation, but this procedure is thought to be demanding. The visualization of 3-dimensional information that is provided by CartoMerge® (BioSense Webster Inc., Diamond Bar, CA, USA) makes the ablation procedure easier. The SoundStar® catheter (BioSense Webster Inc., Diamond Bar, CA, USA)became available in Korea in September 2016. CartoMerge® using a SoundStar® catheter, which we termed as SoundMerge, is a simple way to obtain good CartoMerge® results. In addition, information on catheter stability and ablation intensity at each site are provided by a new ablation annotation system (CARTO® 3 System, VisiTag™ Module [BioSense Webster Inc., Diamond Bar, CA, USA]), which would be helpful for accomplishing durable PV isolation. In this article, we introduce the methodology of SoundMerge and the setting of the VisiTag™ module that we are performing currently. Effective practical use of these new technologies would improve the quality of ablation procedures.

The Myocardial Protection of Immersion Hearts in Perfluorochemicals during Ischemia / 日本心臓血管外科学会雑誌

Topical cardiac hypothermia has unequivocal preservation effects during ischemia, but it has some disadvantages. Topical cooling, especially with ice slush, can injure the phrenic nerve, disturb the equal distribution of the cardioplegic solution due to coronary artery spasm and damage the epicardium. It is easy to prevent cooling injury without topical hypothermia, but the myocardial oxygen demands are increased. In order to supply the myocardium with oxygen for the increased oxygen demands during ischemia, isolated rat hearts were immersed in perfluorochemicals (PFC) which have excellent transportation of oxygen. The effects of immersion in PFC during mild hypothermic ischemia (at 20°C without cardioplegia and at 30°C cardioplegic arrest) on the cardiac function on reperfusion were evaluated. Under 20°C hypothermic ischemia without cardioplegia, cardiac beating was maintained for 20±4 minutes in the hearts were immersed in PFC, and for 10±2 minutes in the hearts that were not immersed in any solution. In the recovery of cardiac function (LVDP and LV_max d<i>p</i>/d<i>t</i>) after mild hypothermic (30°C) cardioplegic arrest, the hearts immersed in PFC showed better results than hearts that were not immersed.