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Practical Pediatric Gastrointestinal Endoscopy - part 2

nguồn nội soi kết nối ánh sáng. Không khí này được định hướng thông qua các kênh không khí ống van khí / nước trên phần điều khiển. Nếu van này là không được bảo hiểm, không khí chỉ đơn giản là thoát khỏi một lỗ ở phía trên cùng của van (xem hình 3.1). Liên tục trút hệ thống thông qua lỗ này làm giảm hao mòn máy bơm. | 14 CHAPTER 3 Fig. 3.6 Schematic of a typical endoscope air water and suction system. endoscope s light source connector. This air is directed via the air channel tube to the air water valve on the control section. If this valve is not covered the air simply exits from a hole in the top of the valve see Fig. 3.1 . Continuously venting the system via this hole reduces wear and tear on the pump. To insufflate the patient the endoscopist simply covers the vent hole with the tip of a finger. This closes the vent and causes air pressure to immediately build up inside the air-feeding system. With the vent closed air is forced down the air channel tube and exits the endoscope through the nozzle on the distal tip. The maximum flow out of the tip of the instrument is typically around 30 cm3 s. A one-way valve is incorporated into the shaft of the air water valve see Fig. 3.1 . This antireflux valve is necessary to hold air in the patient while insufflated. If it were not for this one-way valve in the system air from the patient would flow back into the air nozzle up the insertion tube and out of the hole in the air water valve whenever the operator s finger is lifted off the valve. Water used to clean the objective lens of the endoscope during the procedure is stored in a water bottle attached to the light source or cart see Fig. 3.6 . In addition to feeding air for insufflation the air pump also pressurizes this water container. This forces water out of the bottle and up the universal cord to the air water valve. When the endoscopist depresses the air water valve it allows the water to continue down the water channel EQUIPMENT 15 in the insertion tube and out of the nozzle on the distal tip. The nozzle then directs this water across the surface of the objective lens to clean the lens. In a similar manner suction is also controlled by a valve. A suction line either from a portable suction pump or from the hospital s house suction system is connected to the endoscope. A .