Before starting the study, all nurses who work as senior nurse in the emergency department will be informed. All the Emergency Nurses who are willing to participate in the study (the consent form from the nurses who will be included in the study) will be taken pretest to measure their knowledge about ultrasound and infrared light usage for intravenous access. Then, the 4-hours theoretical and 4-hours practical lesson accompanied by an infrared device and a single-operator with horizontal and longitudinal vascular access with ultrasonography will be explained by the experienced Emergency Medicine Specialist to all the senior nurses . Introduction of ultrasonography device in the theoretical training, principles of using, linear probe and its properties, horizontal and longitudinal axis concepts used in the determination of venous structures, principles of determination of venous structures in ultrasonography, differentiation of artery and nerve structures will be explained. The introduction of the device for infrared light, the principles of operation, the distance between the light and operation area and the positioning of the device will be discussed. Practical trainings will be arranged on horizontal and longitudinal axes by using ultrasound on lifeless forearm mannequin. In the practical lesson in the infrared light device, the device will be kept in a proper distance on the live mannequin, being positioned perpendicular to the area to be treated and identification of the vascular structures while the device is operating. After the theoretical and practical training, all of the senior nurses will be evaluated with posttest and the nurses with a success rate of 80% will be included in the study.

Adult patients and/ or their relatives will be included to study if they meet any of the inclusion criteria and accept the consent form. The randomization of the patients according to the number of nurses participating in the study will be determined by the responsible researchers before the study begins. For example, in the study where 10 senior nurses will participate, the number of targeted patients will be at least 270 and 10 boxes specific to each nurse will be created. These boxes will be kept in the senior nurse room. Each box will have 27 different application methods (9 usg, 9 infrared, 9 standard methods). The nurse who accepts to participate in the research will apply the method according to the procedure which will be randomly drawn from this box. In this way, an equal number of procedures will be provided for each nurse and an equal number of procedures will be provided for each nurse.

The application of the procedure on the longitudinal or horizontal axis will be left to senior nurse discretion. In the infrared light approach, 2 applicators will be operated. While holding the auxiliary infra-red light, the practitioner will perform the operation at a distance of 20 cm perpendicular to the process zone. The place of application will be left to the discretion of the practitioner. In order to establish a standard approach between the procedures performed, 18 gauge catheter will be used at the arm and the forearm areas, 20 gauge for the other regions. After the tourniquet is inserted, the procedure time will be calculated as seconds. In order for the successful vascular access to be considered successful, at least 5 ml of blood should be taken or at least 5 ml of saline fluid should be given. In all three approaches, if there is no success after 2 attempts, the 3rd and subsequent trials will be evaluated as rescue interventions and these interventions will be left to the discretion of the practitioner and this will be recorded observably (standard approach, usg, infra red light, central vascular, intraosseous approach, calling senior nurse, calling emergency medicine physician etc.). For all three approaches, the success of the first trial, the total duration of the procedure (in seconds), the total number of trials, and rescue method need will be recorded.