[Alarming system in real time and high quality display using volumerendering for otologic surgical navigation: a preclinical study]

Objective:The aim of this study is to design and develop a novel navigation framework that alarms the surgeon with sound during drilling and dynamically renders the high quality medical image data. Method:The accuracy of the proposed system were measured with a skull model using paired point registration and the target registration error (TRE) was computed. We segmented the accurate structure of target and compute the minimum distance between the drill tip and the target. Once the drill tip approached the target structures, the system would alarm the surgeon. We proposed a novelty method that used a mask to render the medical image data in real time. Result:The maximum distance error of 90 target points was 1.016 mm, the minimum was 0.427 mm, and the average distance error was (0.74±0.07) mm. The design and development of the alarming system and dynamically rendering the medical image data of navigation system was accomplished. Conclusion:The results show that the accuracy of the navigation system can meet the clinical needs. It also demonstrates the feasibility of the alarm system and dynamic display system and its application prospects.

Effects of inhaled nitric oxide and high-frequency ventilation in rabbits with meconium aspiration

AIM

To evaluate effects of inhaled nitric oxide (iNO) in experimental meconium aspiration treated with high-frequency (HFV) or conventional mechanical ventilation (CMV). Ventilated adult rabbits had meconium instilled intratracheally resulting in respiratory failure as evidenced by more than 50% reduction of dynamic lung compliance (Cdyn) and increase in mean oxygenation index (OI) from 1 to 16. The animals were then allocated to 2 groups treated without (control) or with iNO at 20 ppm (NO). In each group the animals were initially ventilated with CMV or HFV mode for 3 h and then in a crossover fashion with HFV or CMV for another 3 h (CMV-->HFV, HFV-->CMV), respectively. In the first 3 h of treatment, the animals subjected to HFV-CMV in the control, and those with both HFV-CMV and CMV-HFV in the NO group had significantly reduced OI. In the subsequent 3 h, the animals in the control group with CMV-HFV did not improve in OI and those with HFV-CMV had deteriorated. In the NO group with both CMV-HFV and HFV-CMV moderate improvement of OI was observed. Platelet aggregation capability and counts were significantly decreased and bleeding time prolonged in animals receiving iNO treatment. These results suggest that both HFV alone and a combined treatment of iNO with either CMV or HFV are more effective in improving blood oxygenation than that of CMV in this animal model. The influence of iNO on platelet aggregation should be considered.

Serum concentration fluctuation and bioavailability comparison between indomethacin sustained-release and conventional capsules during steady state

The comparison between indomethacin conventional capsule (CC) po 25 mg q 8 h or 25 mg tid and indomethacin sustained-release capsule (SRC) po 25 mg bid in human by crossover design showed that both maximal serum concentration (Cmax) and fluctuation index (FI%) of SRC were significantly lower than those of CC during steady state (P < 0.01). No practical differences were observed between the 2 preparations in the trough serum concentration (Cmin) and area under serum concentration-time profiles (AUC0-tau) (P > 0.05). The time period reaching maximal serum concentration (Tmax) of SRC was much more delayed than that of CC (P < 0.01). It suggested that SRC possesses a better controlled release property and could avoid a higher serum peak concentration of CC.