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Heated humidified high-flow oxygen therapy, administered using a nasal cannula, is called high-flow nasal cannula (HFNC). HFNC has been introduced and is used as a respiratory support mode in patie...

Introduction: The purpose of this study is to assess the efficacy of high-flow nasal cannula (HFNC) compared with non-invasive positive pressure ventilation (NPPV) in prevention of extubation failure in patients with prolonged mechanical ventilation. Methods: This is a prospective, randomized control, single center, clinical trial. Patients who were prolonged mechanically ventilated (>14 days) had been transferred to stepdown unit for weaning. A total of 40 patients were enrolled in our study. After extubation, patients were randomly assigned to HFNC or NPPV treatment group. The major clinical outcomes measured were re-intubation rate, in hospital mortality and length of non-invasive ventilation time after extubation. Patient who had neuromuscular disorders, central respiratory drive disorders, tracheostomy and signed “do not resuscitate” were excluded. Results: The reintubation rate was significantly higher in HFNC group (NPPV 0% vs. HFNC 25%, p =.008), the length of NPPV support after extubation was shorter in NPPV group compared to HFNC group (NPPV 13-hrs vs. HFNC 20-hrs, p =.001). The physiologic variables at one hour after extubation, including PaO2/FiO2, PaCO2, were significantly improved in NPPV group than HFNC group. However, there were no diference in length of hospital stay and mortality. Conclusion: Compared with NPPV, HFNC has higher reintubation rate than NPPV. Our study demonstrated that for those patients who were prolonged mechanically ventilated, NPPV should be applied rather than HFNC after extubation to reduce the extubation failure.

To evaluate the safety and efficacy of catheter mediated radiofrequency (RF) ablation in patients with Wolff-Parkinson-White syndrome, 125 patients with accessory pathway (AP) mediated tachyarrhythmias underwent RF ablation. Right-sided APs were ablated from the atrial aspect of the tricuspid annulus (all from the femoral vein approach) and the left-sided APs were ablated from the atrial or ventricular aspect of the mitral annulus. Immediately after ablation, 3 of 8 APs (38%) and 131 of 137 APs (95%) were ablated successfully with RF through a small-tip (2 mm) and a large-tip (4 mm) electrode catheter, respectively. Seven of the 11 APs where RF ablation failed had a later successful DC ablation. During follow-up (3 to 22 months), 11 of the 114 patients (10%) with successful ablation had return of accessory pathway conduction (2 had recurrence of tachycardia (2%)). Complications included transient myocardial injury (peak CK-MB 15 +/- 3 IU/l), transient proarrhythmic effects (more atrial and ventricular premature beats), accidental AV block (1 patient), cardiac tamponade (1 patient) and suspicion of aortic dissection (1 patient). In successful sessions, procedure and radiation exposure time were 3.8 +/- 0.2 h and 45 +/- 4 min, respectively. This study confirms that RF ablation with a large-tip electrode catheter is an effective and relatively safe nonsurgical method for treatment of Wolff-Parkinson-White syndrome.

Fifty-one consecutive patients underwent modified catheter-mediated direct-current ablation of accessory pathways. Energy was delivered through the distal pair of electrodes (dual electrode configuration) of a 6F quadripolar catheter to the internal surface of the right or left atrioventricular (AV) annulus. In an attempt to prevent the later resumption of accessory pathway conduction, one additional shock was given after the initial successful interruption of accessory pathways. A mean of 2.7 shocks with cumulative energy of 453 +/- 32 Joules/patient interrupted the accessory pathways in 47 patients and modified the accessory pathway conduction in 2 patients. Forty-eight patients were asymptomatic and free of any antiarrhythmic agents with a follow-up ranging from 3-20 months (mean 12 +/- 1 months), without early or late serious complications (AV block or tamponade). Conduction characteristics, concealed or manifest, and recording of accessory pathway activity did not affect the outcome. Mean cumulative energy and number of applications of energy to achieve a successful outcome were lower in patients with concealed (376 +/- 31 Joules, 2.4 +/- 0.2 shocks) than manifest accessory pathways (516 +/- 50 Joules, 2.9 +/- 0.2 shocks). At the successful ablation sites, the mean shortest retrograde ventriculoatrial interval during orthodromic reentrant tachycardia (VA') was 80 +/- 3 msec (78% had VA' less than 90 msec) and was not different between concealed and manifest accessory pathways; the mean shortest antegrade AV interval was 47 +/- 3 msec in manifest preexcitation; the mean ratio of atrial to ventricular wave amplitude was not significantly different between left-sided (0.8 +/- 0.1) and right-sided (1.1 +/- 0.2) accessory pathways (p greater than 0.05). A successful outcome was achieved in 94% of 51 patients. This procedure is relatively safe and effective, regardless of the location of the accessory pathway.