Prostacyclin and nitric oxide donors are the best studied vasodilating agents in experimental sepsis and have shown improved tissue perfusion and oxygen extraction. In several clinical studies prostacyclin has also been shown to have such beneficial effects. Recent studies using orthogonal polarization spectral imaging have shown microcirculatory recruitment by nitric oxide donors in hemodynamically resuscitated septic patients. Whether such therapeutic modalities aimed at recruitment of the microcirculation improve outcome, however, still has to be determined.

We explore the estimation of sensitivity and specificity of diagnostic tests when the true disease state is unknown. Instrumental variables which subdivide the patient population are used. A logistic model, relating these instrumental variables to the (unknown) true disease state is proposed. It is shown that this procedure allows the goodness-of-fit to the resulting model to be tested.

Similar to aviation, diving is performed in an environment in which acute incapacitation may lead to a fatal outcome. In aeromedicine, a pilot is considered “unfit to fly” when the cardiovascular event risk exceeds one percent per annum, the so-called 1% rule. In diving no formal limits to cardiovascular risk have been established. Cardiovascular risk of divers can be calculated using the modified Canadian Cardiovascular Society (CCS) Risk of Harm formula: risk of harm (RH: cardiovascular fatality rate per year during diving: number × 10-5 divers/year) = time diving (TD: number of dives × 10-4) × sudden cardiac incapacitation (SCI: cardiovascular diver event rate per year (number × 10-5/year). The SCI and thus the RH are strongly dependent on age. Using the CCS criterion for RH, 5 × 10-5 divers/year, and considering an average of 25 dives per year per diver, the calculated maximum acceptable SCI is 2%/year, consistent with current practice for dive medical examinations. If the SCI were to exceed 2%/year, a diver could be considered “unfit to dive,” which could particularly benefit older (≥ 50 years) divers, in whom cardiovascular risk factors are often not properly treated. For the prevention of fatal diving accidents due to atherosclerotic cardiovascular disease, a dive medical examination is of limited value for young (<50 years) divers who have no cardiovascular risk factors. Introducing a cardiovascular risk management system for divers may achieve a reduction in fatal diving accidents that result from cardiovascular disease in older divers engaged in both recreational and professional diving.

No abstract