這篇刊在JAMA insights的短文,
雖然標題是敗血症和敗血性休克，
但最主要在介紹VTI的意義和如何測量。
∆VTI(%)=
(VTIpost-PLR – VTIpre-PLR)/[(VTIpost-PLR + VTIpre-PLR)/2] x 100%–
a difference of 10%-15% is predictive of fluid responsiveness.
以下連結到官網可以看到實際執行的教學影片
Video Focused Cardiac Ultrasound to Measure Volume Responsiveness Before and After Passive Leg Raise
本文中最重要的教學資訊:
【Preload can be changed during FoCUS by increasing tidal volumes to approximately 8 to 10 mL/kg in an intubated and sedated patient or by performing a passive leg raise in an intubated or nonintubated patient.9 Administering a larger tidal volume induces a greater dynamic change in cardiac preload via a greater change in intrathoracic pressure throughout the respiratory cycle. A passive leg raise transfers approximately 300 mL of venous blood from the legs to the heart and is achieved by moving a patient from a 45-degree heads-up position to 45-degree legs-up position while the head is kept flat.】
Kaselitz TB, Seymour CW. Point-of-Care Ultrasound in Sepsis and Septic Shock. JAMA. Published online March 17, 2025. doi:10.1001/jama.2025.1983
A5C，其實不是那麼好抓的。
這裡血流經過的就是aortic valve的位置
在PMI的位置掃到apical 4 chamber後微調來掃出apical 5 chamber,
VTI的變化，要慢慢的描繪再來記算是很耗時的啊，
如果用手持式的設備更是難上加難，
掃到好的介面，由機器來自動計算VTi和變化才是順應潮流的趨勢啊。
這是我們先前科內教學時用TE7的smart VTI記錄的影像。
這個介面在急診喘和呼吸急促的患者不太容易取得，
而且也不太容易讓患者左側躺來微調角度及測量，
我個人覺得在急診短時間內要推廣不太容易，
不過多學會個技術在手也不是壞事。
如果有需要更準確的fluid responsiveness的評估，
患者的條件和介面也不會太困難，
這個參數算是比較能反應fluid responsiveness的定義。
