Assessment of Extravascular Lung Water and Cardiac Function in Trimix SCUBA Diving

Marinović, Jasna; Ljubković, Marko; Obad, Ante; Brešković, Toni; Salamunić, Ilza; Denoble, Petar J.; Dujić, Željko

doi:10.1249/mss.0b013e3181c5b8a8

Cited by 29 publications

(31 citation statements)

References 32 publications

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“…Even in the absence of DCS, SCUBA diving is associated with a number of asymptomatic changes that can be detected following a dive. They include generation of silent bubbles and alterations in cardiovascular function, i.e., decrease in ventricular contractility, increase in pulmonary arterial pressure, increased secretion of atrial natriuretic peptide and endothelial dysfunction; and pulmonary function, i.e., change in lung diVusing properties, reduction in spirometric parameters and accumulation of extravascular lung water (Dujic et al 2006;Marabotti et al 1999;Marinovic et al 2009Marinovic et al , 2010Obad et al 2007a).…”

Section: Introductionmentioning

confidence: 99%

Effects of successive air and nitrox dives on human vascular function

et al. 2011

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SCUBA diving is regularly associated with asymptomatic changes in cardiac, pulmonary and vascular function. The aim of this study was to evaluate the changes in vascular/endothelial function following SCUBA diving and to assess the potential difference between two breathing gases: air and nitrox 36 (36% oxygen and 64% nitrogen). Ten divers performed two 3-day diving series (no-decompression dive to 18 m with 47 min bottom time with air and nitrox, respectively), with 2 weeks pause in between. Arterial/endothelial function was assessed using SphygmoCor and flow-mediated dilation measurements, and concentration of nitrite before and after diving was determined in venous blood. Production of nitrogen bubbles post-dive was assessed by ultrasonic determination of venous gas bubble grade. Significantly higher bubbling was found after all air dives as compared to nitrox dives. Pulse wave velocity increased slightly (~6%), significantly after both air and nitrox diving, indicating an increase in arterial stiffness. However, augmentation index became significantly more negative after diving indicating smaller wave reflection. There was a trend for post-dive reduction of FMD after air dives; however, only nitrox diving significantly reduced FMD. No significant differences in blood nitrite before and after the dives were found. We found that nitrox diving affects systemic/vascular function more profoundly than air diving by reducing FMD response, most likely due to higher oxygen load. Both air and nitrox dives increased arterial stiffness, but decreased wave reflection suggesting a decrease in peripheral resistance due to exercise during diving. These effects of nitrox and air diving were not followed by changes in plasma nitrite.

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Section: Introductionmentioning

confidence: 99%

Effects of successive air and nitrox dives on human vascular function

et al. 2011

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“…; Marinovic et al. ). Indeed, the effects of increased central venous pressure may augment PFO recruitment created by breathing against resistance.…”

Section: Discussionmentioning

confidence: 97%

“…; Marinovic et al. ). Increases in left ventricular and atrial pressures may create a left‐to‐right atrial pressure gradient that would oppose right‐to‐left flow through the PFO.…”

Section: Discussionmentioning

confidence: 97%

Inspiratory and expiratory resistance cause right-to-left bubble passage through the foramen ovale

et al. 2018

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A patent foramen ovale (PFO) is linked to increased risk of decompression illness in divers. One theory is that venous gas emboli crossing the PFO can be minimized by avoiding lifting, straining and Valsalva maneuvers. Alternatively, we hypothesized that mild increases in external inspiratory and expiratory resistance, similar to that provided by a SCUBA regulator, recruit the PFO. Nine healthy adults with a Valsalva‐proven PFO completed three randomized trials (inspiratory, expiratory, and combined external loading) with six levels of increasing external resistance (2–20 cmH2O/L/sec). An agitated saline contrast echocardiogram was performed at each level to determine foramen ovale patency. Contrary to our hypothesis, there was no relationship between the number of subjects recruiting their PFO and the level of external resistance. In fact, at least 50% of participants recruited their PFO during 14 of 18 trials and there was no difference between the combined inspiratory, expiratory, or combined external resistance trials (P > 0.05). We further examined the relationship between PFO recruitment and intrathoracic pressure, estimated from esophageal pressure. Esophageal pressure was not different between participants with and without a recruited PFO. Intrasubject variability was the most important predictor of PFO patency, suggesting that some individuals are more likely to recruit their PFO in the face of even mild external resistance. Right‐to‐left bubble passage through the PFO occurs in conditions that are physiologically relevant to divers. Transthoracic echocardiography with mild external breathing resistance may be a tool to identify divers that are at risk of PFO‐related decompression illness.

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“…However, a recent study has shown that even presumably safe dives with few VGE and no DCI symptoms were associated with significant cardiac strain and increased levels of BNP (Marinovic et al. ). Grassi et al.…”

Section: Discussionmentioning

confidence: 99%

Effects of hyperbaric oxygen preconditioning on cardiac stress markers after simulated diving

et al. 2013

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Hyperbaric oxygen preconditioning (HBO-PC) can protect the heart from injury during subsequent ischemia. The presence of high loads of venous gas emboli (VGE) induced by a rapid ambient pressure reduction on ascent from diving may cause ischemia and acute heart failure. The aim of this study was to investigate the effect of diving-induced VGE formation on cardiac stress marker levels and the cardioprotective effect of HBO-PC. To induce high loads of VGE, 63 female Sprague–Dawley rats were subjected to a rapid ambient pressure reduction from a simulated saturation dive (50 min at 709 kPa) in a pressure chamber. VGE loads were measured for 60 min in anesthetized animals by the use of ultrasonography. The animals were divided into five groups. Three groups were exposed to either diving or to HBO-PC (100% oxygen, 38 min at 303 kPa) with a 45 or 180 min interval between HBO-PC and diving. Two additional groups were used as baseline controls for the measurements; one group was exposed to equal handling except for HBO-PC and diving, and the other group was completely unexposed. Diving caused high loads of VGE, as well as elevated levels of the cardiac stress markers, cardiac troponin T (cTnT), natriuretic peptide precursor B (Nppb), and αB-crystallin, in blood and cardiac tissue. There were strong positive correlations between VGE loads and stress marker levels after diving, and HBO-PC appeared to have a cardioprotective effect, as indicated by the lower levels of stress marker expression after diving-induced VGE formation.

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Assessment of Extravascular Lung Water and Cardiac Function in Trimix SCUBA Diving

Cited by 29 publications

References 32 publications

Effects of successive air and nitrox dives on human vascular function

Effects of successive air and nitrox dives on human vascular function

Inspiratory and expiratory resistance cause right-to-left bubble passage through the foramen ovale

Effects of hyperbaric oxygen preconditioning on cardiac stress markers after simulated diving

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