Stecka Anna M, Gólczewski Tomasz, Grabczak Elżbieta M, Zieliński Krzysztof, Michnikowski Marcin, Zielińska-Krawczyk Monika, Korczyński Piotr, Krenke Rafał
1 Nalecz Institute of Biocybernetics and Biomedical Engineering, Polish Academy of Sciences, Warsaw, Poland.
2 Department of Internal Medicine, Pulmonary Diseases & Allergy, Medical University of Warsaw, Warsaw, Poland.
Int J Artif Organs. 2018 Nov;41(11):690-697. doi: 10.1177/0391398818793354. Epub 2018 Aug 24.
: Some controversies exist on the effect of therapeutic thoracentesis (TT) on arterial blood oxygen tension. The aim of this study was to evaluate this issue using a previously developed virtual patient.
: The analysis was based and supported by clinical data collected during 36 TT. Pleural pressure and transcutaneous oxygen and carbon dioxide pressures (PtcO and PtcCO) were measured during pleural fluid withdrawal. Arterial blood oxygen tension and arterial CO tension (PaO and PaCO) were analysed in simulations that mimicked TT. Minute ventilation was adjusted to maintain arterial CO tension at a constant level unless arterial blood oxygen tension fell below 8 kPa. Specifically, the influence of hypoxic pulmonary vasoconstriction efficiency was tested.
: In patients, PtcCO remained at an approximately constant level (average amplitude: 0.63 ± 0.29 kPa), while some fluctuations of PtcO2 were observed (amplitude: (1.65 ± 1.18 kPa) were observed. In 42% of patients, TT was associated with decrease in PtcCO. Simulations showed the following: (a) there were similar PaO fluctuations in the virtual patient; (b) the lower the hypoxic pulmonary vasoconstriction efficiency, the more pronounced the PaO fall during fluid withdrawal; and (c) the lower the atelectatic lung areas recruitment rate, the slower the PaO normalization. The decrease in PaO was caused by an increase of pulmonary shunt.
: Therapeutic thoracentesis may cause both an increase and a decrease in PaO during the procedure. Pleural pressure decrease, caused by pleural fluid withdrawal, improves the perfusion of atelectatic lung areas. If the rate of recruitment of these areas is low, a lack of ventilation causes the arterial blood oxygen tension to fall. Effective hypoxic pulmonary vasoconstriction may protect against the pulmonary shunt.
治疗性胸腔穿刺术（TT）对动脉血氧张力的影响存在一些争议。本研究的目的是使用先前开发的虚拟患者来评估这个问题。
该分析基于36次TT过程中收集的临床数据，并得到其支持。在抽胸水过程中测量胸膜压力、经皮氧和二氧化碳压力（PtcO和PtcCO）。在模拟TT的过程中分析动脉血氧张力和动脉血二氧化碳张力（PaO和PaCO）。除非动脉血氧张力降至8kPa以下，分钟通气量会进行调整以维持动脉血二氧化碳张力在恒定水平。具体而言，测试了低氧性肺血管收缩效率的影响。
在患者中，PtcCO保持在大致恒定水平（平均波动幅度：0.63±0.29kPa），而观察到PtcO2有一些波动（波动幅度：1.65±1.18kPa）。在42%的患者中，TT与PtcCO降低有关。模拟结果显示：（a）虚拟患者中存在类似的PaO波动；（b）低氧性肺血管收缩效率越低，抽液过程中PaO下降越明显；（c）肺不张区域的复张率越低，PaO恢复正常的速度越慢。PaO降低是由肺内分流增加引起的。
治疗性胸腔穿刺术在操作过程中可能导致PaO升高或降低。抽胸水引起的胸膜压力降低改善了肺不张区域的灌注。如果这些区域的复张率较低，通气不足会导致动脉血氧张力下降。有效的低氧性肺血管收缩可能防止肺内分流。
