Keidan Ilan, Sidi Avner, Ben-Menachem Erez, Derazne Estela, Berkenstadt Haim
Anesthesiology Department, University of Florida, Gainesville, FL, USA.
Anesthesiology Department, University of Florida, Gainesville, FL, USA.
J Clin Anesth. 2015 Nov;27(7):585-8. doi: 10.1016/j.jclinane.2015.07.004. Epub 2015 Aug 15.
Intravenous catheters are ubiquitous among modern medical management of patients, yet misplaced or tissued cannulas can result in serious iatrogenic injury due to infiltration or extravasation of injectate. Prevention is difficult, and currently few reliable tests exist to confirm intravascular placement of catheters in awake spontaneously breathing patients.
Twenty conscious spontaneously breathing healthy volunteers were injected with 50 mL normal saline and 50 mL 4.2%, or 50 mL 2.1%, or 20 mL 4.2% sodium bicarbonate in a random order. A blinded anesthetist observed continuous sampling of exhaled carbon dioxide and was asked to differentiate between the sodium bicarbonate and saline injections. Peak increase in measured exhaled carbon dioxide was also calculated.
Exhaled carbon dioxide increased significantly in participants injected with intravenous sodium bicarbonate. Mean peak increase was 7.4 mm Hg (±2.1 mm Hg) for 50 mL 4.2% sodium bicarbonate, 4.7 mm Hg (±2.5 mm Hg) for 20 mL 4.2% sodium bicarbonate, and 3.5 mm Hg (±1. 8 mm Hg) for 50 mL 2.1% sodium bicarbonate. The blinded observer correctly identified the injection as sodium bicarbonate or normal saline in every instance.
Intravenous injection of dilute sodium bicarbonate with exhaled carbon dioxide monitoring reliably confirms correct intravascular placement of a catheter. A transient increase of exhaled carbon dioxide by 10% or more is an objective and reliable confirmation of intravascular location of the catheter. We recommend using 20 mL of 4.2% sodium bicarbonate to minimize the mEq dose of sodium bicarbonate required.
静脉导管在现代患者医疗管理中无处不在，但插管位置不当或形成组织包裹的套管可能因注射剂的渗漏或外渗导致严重的医源性损伤。预防很困难，目前几乎没有可靠的测试来确认清醒自主呼吸患者的导管血管内放置情况。
20名清醒自主呼吸的健康志愿者按随机顺序分别注射50毫升生理盐水、50毫升4.2%的碳酸氢钠或50毫升2.1%的碳酸氢钠，或20毫升4.2%的碳酸氢钠。一名不知情的麻醉师观察呼出二氧化碳的连续采样，并被要求区分碳酸氢钠注射和生理盐水注射。还计算了呼出二氧化碳测量值的峰值增加。
静脉注射碳酸氢钠的参与者呼出二氧化碳显著增加。50毫升4.2%的碳酸氢钠平均峰值增加7.4毫米汞柱（±2.1毫米汞柱），20毫升4.2%的碳酸氢钠为4.7毫米汞柱（±2.5毫米汞柱），50毫升2.1%的碳酸氢钠为3.5毫米汞柱（±1.8毫米汞柱）。不知情的观察者在每种情况下都能正确识别注射的是碳酸氢钠还是生理盐水。
静脉注射稀释的碳酸氢钠并监测呼出二氧化碳可可靠地确认导管正确放置在血管内。呼出二氧化碳短暂增加10%或更多是导管血管内位置的客观可靠确认。我们建议使用20毫升4.2%的碳酸氢钠，以尽量减少所需碳酸氢钠的毫当量剂量。
