ABSTRACT
Objective To observe the relationship of right internal jugular vein (RIJV)and common carotid artery (CAA)by scanning strictly from the anterior to posterior using ultrasound at different head rotation.Methods Using ultrasonic scanning,the anatomic features of RIJV and CAA both at thyroid cartilage level (prominentia laryngea level)and at the apex of the angle formed by the division of the sternocleidomastoid muscle (triangle level)with 0°,1 5°,30° and 45° right rotation were observed in 131 patients with ASA physical status Ⅰ or Ⅱ (male 55 cases,female 76 cases, aged 18~74 years).Based on the ultrasound images,the safe puncture range,the overlapping ratio, the angle between the horizontal axis and the line from the midpoint of RIJV to that of CAA (αangle) were measured.In addition,the relationship between the RIJV and CAA was defined as anterior-lat-eral, lateral, posterior-lateral or extremely-posterior-lateral position according to α angle. Results The safe puncture range of RIJV augmented as head rotated from 0° to 30° position(P <0.05);The safe puncture range of RIJV at triangle level was significantly higher than at prominentia laryngea level at all the four head positions(P <0.05).The overlapping degree decreased as head rota-ted from 0°to 30°head position at prominentia laryngea level(P <0.05).No siginificant differences of the overlapping degree were found between head positons at triangle level;The overlapping degree at triangle level was less than at prominentia laryngea level when at 0°and 1 5°head positon(P <0.05). At both prominentia laryngea and triangle levels,RIJV located mainly at lateral and posterior-lateral positions.In addition,the part of lateral position increased while the part of posterior-lateral position decreased as the head rotated from 0°to 45°position(P <0.05).Conclusion The puncture conditions for RIJV catheterization were more optimal at 30°to 45°head rotation for a safer puncture range and less overlapping between RIJV and CAA.RIJV located mainly at lateral and posterior-lateral positions at different rotations and RIJV gradually shifted to lateral position while head rotation increasing.It would be much better to select triangle level for central venous catheterization than prominentia laryn-gea level.