Department of Physiology, University of Split School of Medicine, University Hospital Split, Split, Croatia.
J Appl Physiol (1985). 2012 Jan;112(1):91-5. doi: 10.1152/japplphysiol.00943.2011. Epub 2011 Oct 13.
Scuba diving is associated with breathing gas at increased pressure, which often leads to tissue gas supersaturation during ascent and the formation of venous gas emboli (VGE). VGE crossover to systemic arteries (arterialization), mostly through the patent foramen ovale, has been implicated in various diving-related pathologies. Since recent research has shown that arterializations frequently occur in the absence of cardiac septal defects, our aim was to investigate the mechanisms responsible for these events. Divers who tested negative for patent foramen ovale were subjected to laboratory testing where agitated saline contrast bubbles were injected in the cubital vein at rest and exercise. The individual propensity for transpulmonary bubble passage was evaluated echocardiographically. The same subjects performed a standard air dive followed by an echosonographic assessment of VGE generation (graded on a scale of 0-5) and distribution. Twenty-three of thirty-four subjects allowed the transpulmonary passage of saline contrast bubbles in the laboratory at rest or after a mild/moderate exercise, and nine of them arterialized after a field dive. All subjects with postdive arterialization had bubble loads reaching or exceeding grade 4B in the right heart. In individuals without transpulmonary passage of saline contrast bubbles, injected either at rest or after an exercise bout, no postdive arterialization was detected. Therefore, postdive VGE arterialization occurs in subjects that meet two criteria: 1) transpulmonary shunting of contrast bubbles at rest or at mild/moderate exercise and 2) VGE generation after a dive reaches the threshold grade. These findings may represent a novel concept in approach to diving, where diving routines will be tailored individually.
水肺潜水与呼吸高压气体有关，这通常会导致上升过程中组织气体过饱和，并形成静脉气体栓塞（VGE）。VGE 通过未闭卵圆孔（patent foramen ovale）交叉进入体循环动脉（arterialization），这与各种潜水相关病理有关。由于最近的研究表明，即使没有心脏间隔缺损，动脉化也经常发生，因此我们的目的是研究这些事件的发生机制。对未检测到卵圆孔未闭的潜水员进行实验室测试，在休息和运动时将搅动的盐水对比气泡注入肘静脉。通过超声心动图评估跨肺气泡通过的个体倾向。同一批受试者进行标准空气潜水，然后对 VGE 生成（按 0-5 级评分）和分布进行超声评估。在实验室中，34 名受试者中有 23 名在休息或轻度/中度运动时允许盐水对比气泡通过肺，其中 9 名在野外潜水后出现动脉化。所有潜水后出现动脉化的受试者右心的气泡负荷达到或超过 4B 级。在休息或运动后注射盐水对比气泡但未通过肺的受试者中，未检测到潜水后动脉化。因此，潜水后 VGE 动脉化发生在满足以下两个标准的受试者中：1）在休息或轻度/中度运动时对比气泡通过肺的跨肺分流，以及 2）潜水后 VGE 生成达到阈值等级。这些发现可能代表了潜水方法的新概念，其中潜水常规将根据个体情况进行定制。
