Techniques of rapid sequence induction and intubation at a university teaching hospital

BACKGROUND: Rapid sequence induction and intubation(RSII) is a medical procedure involving a prompt induction of general anesthesia by using cricoid pressure that prevents regurgitation of gastric contents. The factors affecting RSII are prophylaxis for aspiration, preoxygenation, drug and equipment preparation for RSII, ventilation after induction till intubation and patient condition. We sometimes saw diffi culties with the practice of this technique in our hospital operation theatres. The aim of this study was to assess the techniques of rapid sequence induction and intubation.METHODS: Hospital based observational study was conducted with a standardized checklist. All patients who were operated upon under general anesthesia during the study period were included. The techniques of RSII were observed during the induction of anesthesia by trained anesthetists.RESULTS: Altogether 140 patients were included in this study with a response rate of 95.2%. Prophylaxis was not given to 130 patients(92.2%), and appropriate drugs were not used for RSII in 73 patients(52.1%), equipments for diffi cult intubation in 21(15%), suction machines with catheter not connected and turned on in 122(87.1%), ventilation for patients after induction and before intubation in 41(29.3%), cricoid pressure released before cuff inflation in 12(12.1%), and difficult intubation in 8(5.7%), respectively. RSII with cricoid pressure was applied appropriately in 94(67.1%) patients, but cricoid pressure was not used in 46(32.9%) patients.CONCLUSIONS: The techniques of rapid sequence induction and intubation was low. Training should be given for anesthetists about the techniques of RSII.

PROTOTYPE SURFACE MICRO- PRECISION IN FUSED DEPOSITION MODELING PROCESS

To aim at prototype parts fabricated with fused deposition modeling （FDM） process, the problems how to improve and enhance their surface micro-precision are studied. The producing mechanism of surface roughness is explained with three aspects concretely including the principle error of rapid prototyping （RP） process, the inherent characteristics of FDM process, and some mi- cro-scratches on the surface of the extruded fiber. Based on the micro-characters of section shape of the FDM prototype, a physical model reflecting the outer shape characters is abstracted. With the physical simplified and deduced, the evaluating equations of surface roughness are acquired. According to the FDM sample parts with special design for experimental measurement, the real surface roughness values of different inclined planes are obtained. And the measuring values of surface roughness are compared with the calculation values. Furthermore, the causes of surface roughness deviation between measuring values and calculation values are respectively analyzed and studied. With the references of analytic conclusions, the measuring values of the experimental part surface are revised, and the revised values nearly accord with the calculation values. Based on the influencing principles of FDM process parameters and special post processing of FDM prototype parts, some concrete measures are proposed to reduce the surface roughness of FDM parts, and the applying effects are better.