Nebulized heparin for inhalation injury in burn patients:a systematic review and meta-analysis

Background:Smoke inhalation injury increases overall burn mortality.Locally applied heparin attenuates lung injury in burn animal models of smoke inhalation.It is uncertain whether local treatment of heparin is benefit for burn patients with inhalation trauma.We systematically reviewed published clinical trial data to evaluate the effectiveness of nebulized heparin in treating burn patients with inhalation injury.Methods:A systematic search was undertaken in PubMed,the Cochrane Library,Embase,Web of Science,the Chinese Journals Full-text Database,the China Biomedical Literature Database and the Wanfang Database to obtain clinical controlled trails evaluating nebulized heparin in the treatment of burn patients with inhalation injury.Patient and clinical characteristics,interventions and physiological and clinical outcomes were recorded.Cochrane Risk of Bias Evaluation Tool and the Newcastle–Ottawa Scale were used to evaluate data quality.Potential publication bias was assessed by Egger’s test.A sensitivity analysis was conducted to assess the stability of the results.The meta-analysis was conducted in R 3.5.1 software.Results:Nine trials were eligible for the systematic review and meta-analysis.Nebulized heparin can reduce lung injury and improve lung function in burn patients with inhalation injury without abnormal coagulation or bleeding,but the findings are still controversial.Mortality in the heparintreated group was lower than that of the traditional treatment group(relative risk(RR)0.75).The duration of mechanical ventilation(DOMV)was shorter in the heparin-treated group compared to the traditional treatment group(standardized mean difference(SMD)−0.78).Length of hospital stay was significantly shorter than that in the traditional treatment group(SMD−0.42),but incidence rates of pneumonia and unplanned reintubation were not significantly different in the study groups(RRs 0.97 and 0.88,respectively).No statistically significant publication biases were detected for the above clinical endpoints(p>0.05).Conclusions:Based on conventional aerosol therapy,heparin nebulization can further reduce lung injury,improve lung function,shorten DOMV and length of hospital stay,and reduce mortality,although it does not reduce the incidence of pneumonia and/or the unplanned reintubation rate.

Characteristics of surface acoustic waves in (1120) ZnO film/R-sapphire substrate structures

（1120）ZnO film/R-sapphire substrate structure is promising for high frequency acoustic wave devices. The propagation characteristics of SAWs, including the Rayleigh waves along [0001] direction and Love waves along [1100] direction, are investigated by using 3 dimensional finite element method （3D-FEM）. The phase velocity （vp）, electromechanical coupling coefficient （k2）, temperature coefficient of frequency （TCF） and reflection coefficient （r） of Rayleigh wave and Love wave devices are theoretically analyzed. Furthermore, the influences of ZnO films with different crystal orientation on SAW properties are also investigated. The results show that the 1st Rayleigh wave has an exceedingly large/d of 4.95% in （90°, 90°, 0°） （1120）ZnO film/R-sapphire substrate associated with a phase velocity of 5300 m/s; and the 0th Love wave in （0°, 90°, 0°） （1120）ZnO film/R-sapphire substrate has a maximum k2 of 3.86% associated with a phase velocity of 3400 m/s. And （1120）ZnO film/R-sapphire substrate structures can be used to design temperature-compensated and wide-band SAW devices. All of the results indicate that the performances of SAW devices can be optimized by suitably selecting ZnO films with different thickness and crystal orientations deposited on R-sapphire substrates.