Orliaguet G A, Catoire P, Liu N, Beydon L, Bonnet F
Department of Anesthesiology, Hôpital Henri Mondor, Créteil, France.
Transplantation. 1994 Sep 27;58(6):655-8.
The effects of apnea testing-induced respiratory acidosis on left ventricular function (LVF) are still controversial. The aim of the study was to assess LVF during apnea testing using transesophageal echocardiography (TEE). Twenty consecutive patients suspected of brain death, hemodynamically stable, and considered as potential organ donors were prospectively studied. A 20-min apnea test was performed after obtaining a PaCO2 > 35 mmHg and 20 min of FIO2 1 ventilation. LVF was assessed using TEE with a CFM 750 (Diasonic) connected to a 5 MHz probe. Heart rate (HR), mean arterial pressure (MAP), left ventricle end-diastolic and systolic area (LVEDA, LVESA), and LVF assessed by fractional area changes (FAC), systolic wall motion (SWM) scores, and blood gases were recorded at baseline, and after 5, 10, 15, and 20 min of apnea testing. In 19 patients, no spontaneous respiratory movement occurred during the standard 20-min period. In one patient (No. 15), the apnea test had to be stopped after 10 min because of hypoxia. HR, LVEDA, LVESA, and SWM were not significantly modified during the study. There was a progressive statistically significant decrease in MAP during apnea (from 77 +/- 10 to 63 +/- 11 mmHg), associated with a statistically significant increase in FAC at 20 min (from 48 +/- 13 to 56 +/- 8%). PaCO2 progressively rose (from 40 +/- 3 to 95 +/- 11 mmHg), associated with a decrease in pH (from 7.42 +/- 0.06 to 7.09 +/- 0.08). At the same time, PaO2 decreased slightly in all patients, but values remained well above hypoxic levels, except for one patient. Despite severe respiratory acidosis the increase in FAC suggests that apnea testing is well tolerated for brain death assessment.
呼吸暂停试验诱发的呼吸性酸中毒对左心室功能（LVF）的影响仍存在争议。本研究的目的是使用经食管超声心动图（TEE）评估呼吸暂停试验期间的左心室功能。对20例连续的疑似脑死亡、血流动力学稳定且被视为潜在器官捐献者的患者进行了前瞻性研究。在获得动脉血二氧化碳分压（PaCO2）>35 mmHg且吸入氧分数（FIO2）为1进行20分钟通气后，进行了20分钟的呼吸暂停试验。使用连接5 MHz探头的CFM 750（Diasonic）型TEE评估左心室功能。在基线以及呼吸暂停试验5、10、15和20分钟后，记录心率（HR）、平均动脉压（MAP）、左心室舒张末期和收缩末期面积（LVEDA、LVESA），以及通过面积变化分数（FAC）、收缩期壁运动（SWM）评分评估的左心室功能和血气。19例患者在标准的20分钟期间未出现自主呼吸运动。1例患者（第15号）因缺氧在10分钟后不得不停止呼吸暂停试验。在研究期间，HR、LVEDA、LVESA和SWM无显著变化。呼吸暂停期间MAP有统计学意义的逐渐下降（从77±10降至63±11 mmHg），同时20分钟时FAC有统计学意义的增加（从48±13升至56±8%）。PaCO2逐渐升高（从40±3升至95±11 mmHg），pH值下降（从7.42±0.06降至7.09±0.08）。与此同时，除1例患者外，所有患者的动脉血氧分压（PaO2）均略有下降，但仍远高于缺氧水平。尽管存在严重的呼吸性酸中毒，但FAC的增加表明呼吸暂停试验在脑死亡评估中耐受性良好。
