Ghai V, Del Nido P, Nakamura H, Fujii Y, Vidyasagar D, Wilson G
Department of Pediatrics, University of Illinois College of Medicine, Chicago.
Crit Care Med. 1991 May;19(5):736-41. doi: 10.1097/00003246-199105000-00023.
We investigated the hypothesis that, in a newborn piglet during normoxia, hypoxia, and hyperoxia, increasing aortic pressure transiently by intermittent short-duration aortic compression would affect left-to-right shunting of blood and thus increase pulmonary artery blood flow, pulmonary arterial PO2, and aortic PO2 proximal to the point of compression. We also investigated whether a balloon atrial septostomy, by providing an open channel for communication between the right- and left-sided circulations, would further improve pulmonary blood flow and aortic PO2. Studies were performed in eight 7- to 10-day-old newborn piglets in three phases (FIO2 of 0.21, 0.12, and 1.0) before and after balloon arterial septostomy in each piglet. Blood gas measurements and hemodynamic variables were recorded before and at the end of a 30-sec period of aortic compression.
During aortic compression, all the animals demonstrated a 50 to 70 mm Hg increase in aortic pressure proximal to the compression. Before balloon septostomy, there were 21%, 41%, and 8% increases in aortic PO2 in the room air, hypoxic, and hyperoxic phases of the experiment, respectively. There were also statistically significant increments in pulmonary blood flow and arterial pressures. After balloon septostomy, there were 35%, 25%, and 21% increments in aortic PO2 during the room air, hypoxic, and hyperoxic phases of the experiment, respectively. However, there was no statistically significant further improvement in the effects of aortic compression on PO2 with septostomy compared with those effects before septostomy.
Our results suggest that increasing systemic arterial pressures in order to forcibly affect left-to-right shunting of blood may be potentially beneficial in the management of hypoxia in situations where low pulmonary artery blood flow may be contributing to hypoxia, e.g., in persistent pulmonary hypertension of the newborn.
我们研究了这样一个假设，即在新生仔猪处于常氧、低氧和高氧状态时，通过间歇性短时间主动脉压迫使主动脉压力短暂升高，会影响血液的左向右分流，从而增加肺动脉血流量、肺动脉血氧分压（PO2）以及压迫点近端的主动脉PO2。我们还研究了球囊房间隔造口术通过为左右侧循环之间提供一个开放通道，是否会进一步改善肺血流量和主动脉PO2。对8只7至10日龄的新生仔猪分三个阶段（吸入氧分数分别为0.21、0.12和1.0）进行研究，每个仔猪在球囊动脉造口术前后各进行一次。在主动脉压迫30秒之前和结束时记录血气测量值和血流动力学变量。
在主动脉压迫期间，所有动物压迫点近端的主动脉压力均升高50至70毫米汞柱。在球囊房间隔造口术之前，实验的常氧、低氧和高氧阶段主动脉PO2分别增加了21%、41%和8%。肺血流量和动脉压也有统计学意义的增加。球囊房间隔造口术后，实验的常氧、低氧和高氧阶段主动脉PO2分别增加了35%、25%和21%。然而，与造口术前相比，球囊造口术对主动脉压迫对PO2影响的进一步改善并无统计学意义。
我们的结果表明，在肺动脉血流量低可能导致缺氧的情况下，如新生儿持续性肺动脉高压，通过升高体循环动脉压力来强行影响血液的左向右分流可能对缺氧管理有潜在益处。
