Nelle M, Zilow E P, Linderkamp O
Department of Pediatrics, University of Heidelberg, Germany.
Intensive Care Med. 1997 Jun;23(6):671-6. doi: 10.1007/s001340050392.
Mechanical ventilation may impair cardiovascular function if the transpulmonary pressure rises. Studies on the effects of high-frequency oscillatory ventilation (HFOV) on cardiovascular functions have yielded conflicting results. This study was done to compare alterations in left ventricular output and blood flow velocities in the anterior cerebral artery, internal carotid artery, and celiac artery using a Doppler ultrasound device before and 2 h after initiating HFOV in neonates with respiratory distress syndrome (RDS) or pulmonary interstitial emphysema (PIE).
Prospective clinical study.
Neonatal intensive care unit in a perinatal center.
18 critically ill infants (postnatal age 47 +/- 12 h; mean +/- SD) were studied before and during HFOV (piston oscillator). Indications for HFOV were severe respiratory failure due to PIE (n = 10) and severe surfactant deficiency (RDS, n = 8). In the RDS group, gestational age was 27 +/- 6 weeks (range 26-31 weeks) and birth-weight 1620 +/- 380 g (range 850-1970 g). In the PIE group, gestational age was 28 +/- 2 weeks (range 26-36 weeks) and birth-weight 1740 +/- 470 g (range 890-2760 g).
During HFOV, mean airway pressure was maintained at the same level as during intermittent mandatory ventilation in both groups (RDS, 12 +/- 2 cmH2O; PIE, 10 +/- 2 cmH2O). Compared to intermittent mandatory ventilation, several of the 12 parameters studied changed significantly (p < 0.004) during HFOV. In the RDS group, the partial pressure of oxygen in arterial blood/fractional inspired oxygen (PaO2/FIO2) ratio increased from 56 +/- 9 to 86 +/- 7 and partial pressure of carbon dioxide in arterial blood (PaCO2) decreased from 49 +/- 4 to 35 +/- 3 mmHg. In the PIE group, PaO2/FIO2 ratio increased from 63 +/- 8 to 72 +/- 7 and PaCO2 decreased from 63 +/- 7 to 40 +/- 5 mmHg. In the PIE group, heart rate decreased (135 +/- 15 before HFOV vs 115 +/- 14 min-1 during HFOV) and mean systolic blood pressure increased (before 43 +/- 4 vs 51 +/- 4 mmHg during HFOV) significantly, whereas these parameters did not change in the RDS group. Left ventricular output increased significantly in the PIE group (210 +/- 34 before vs 245 +/- 36 ml/kg per min during HFOV; p < 0.004), but not in the RDS group (225 +/- 46 before vs 248 +/- 47 ml/kg per min during HFOV; k < 0.05). Shortening fraction and systemic resistance did not change in either group. In the PIE group, mean blood flow velocities in the internal carotid artery (+59%), anterior cerebral artery (+65%) and celiac artery (+45%) increased significantly but did not change in the RDS group.
The results show that HFOV as used in this study, improves oxygenation, CO2 elimination, and circulation in infants with RDS and PIE. However, systemic, cerebral, and intestinal circulation improved more in neonates with PIE than in those with RDS. This may be due to higher pulmonary compliance in infants with PIE when compared to those with RDS.
如果跨肺压升高，机械通气可能会损害心血管功能。关于高频振荡通气（HFOV）对心血管功能影响的研究结果相互矛盾。本研究旨在使用多普勒超声设备比较呼吸窘迫综合征（RDS）或肺间质肺气肿（PIE）新生儿在开始HFOV前及开始后2小时左心室输出量以及大脑前动脉、颈内动脉和腹腔动脉血流速度的变化。
前瞻性临床研究。
围产期中心的新生儿重症监护病房。
18例危重症婴儿（出生后年龄47±12小时；均值±标准差）在HFOV（活塞式振荡器）前及期间接受研究。HFOV的指征为PIE导致的严重呼吸衰竭（n = 10）和严重表面活性物质缺乏（RDS，n = 8）。在RDS组中，胎龄为27±6周（范围26 - 31周），出生体重1620±380克（范围850 - 1970克）。在PIE组中，胎龄为28±2周（范围26 - 36周），出生体重1740±470克（范围890 - 2760克）。
在HFOV期间，两组平均气道压均维持在与间歇强制通气期间相同水平（RDS组，12±2 cmH₂O；PIE组，10±2 cmH₂O）。与间歇强制通气相比，所研究的12项参数中有几项在HFOV期间发生了显著变化（p < 0.004）。在RDS组中，动脉血氧分压/吸入氧分数（PaO₂/FIO₂）比值从56±9升至86±7，动脉血二氧化碳分压（PaCO₂）从49±4降至35±3 mmHg。在PIE组中，PaO₂/FIO₂比值从63±8升至72±7，PaCO₂从63±7降至40±5 mmHg。在PIE组中，心率显著下降（HFOV前135±15次/分钟，HFOV期间115±14次/分钟），平均收缩压显著升高（HFOV前43±4 mmHg，HFOV期间51±4 mmHg），而这些参数在RDS组中未改变。PIE组左心室输出量显著增加（HFOV前210±34 vs HFOV期间245±36 ml/kg每分钟；p < 0.004），但RDS组未增加（HFOV前225±46 vs HFOV期间248±47 ml/kg每分钟；k < 0.05）。两组的缩短分数和全身阻力均未改变。在PIE组中，颈内动脉（+59%）、大脑前动脉（+65%）和腹腔动脉（+45%）的平均血流速度显著增加，但在RDS组中未改变。
结果表明，本研究中使用的HFOV可改善RDS和PIE婴儿的氧合、二氧化碳清除及循环。然而，PIE新生儿的全身、脑和肠道循环改善程度比RDS新生儿更大。这可能是因为与RDS婴儿相比，PIE婴儿的肺顺应性更高。
