Intercostal and vastus lateralis microcirculatory response to a sympathoexcitatory manoeuvre in patients with chronic obstructive pulmonary disease.

Patients with COPD present with systemic vascular malfunctioning and their microcirculation is possibly more fragile to overcome an increase in the sympathetic vasoconstrictor outflow during sympathoexcitatory situations. To test the skeletal muscle microvascular responsiveness to sympathoexcitation, we asked patients with COPD and age- and sex-matched controls to immerse a hand in iced water [Cold Pressor Test (CPT)]. Near-infrared spectroscopy detection of the indocyanine green dye in the intercostal and vastus lateralis microcirculation provided a blood flow index (BFI). BFI divided by mean blood pressure (MBP) provided an index of microvascular conductance (BFI/MBP). The CPT decreased BFI and BFI/MBP in the intercostal (P = 0.01 and < 0.01, respectively) and vastus lateralis (P = 0.08 and 0.03, respectively) only in the COPD group, and the per cent BFI and BFI/MBP decrease was similar between muscles (P = 0.78 and 0.85, respectively). Thus, our findings support that sympathoexcitation similarly impairs intercostal and vastus lateralis microvascular regulation in patients with COPD.

Inspiratory Muscle Training Improves Intercostal and Forearm Muscle Oxygenation in Patients With Chronic Heart Failure: Evidence of the Origin of the Respiratory Metaboreflex.

BACKGROUND: The impact of inspiratory muscle training (IMT) on respiratory and peripheral muscle oxygenation and perfusion during inspiratory muscle fatigue in patients with chronic heart failure (HF) has not been established. METHODS AND RESULTS: Twenty-six patients with chronic HF were randomly assigned to either 8 weeks of IMT or a control group. Inspiratory fatigue was induced by means of a progressive inspiratory resistive loading protocol until there was an inability to sustain inspiratory pressure, when the inspiratory muscle metaboreflex should be activated. The main outcomes were intercostal and forearm muscle oxygen saturation and deoxygenation as measured by means of near-infrared spectroscopy (NIRS) and blood lactate levels. Inspiratory muscle strength was increased by 78% (P <.001) after 8 weeks of participation in the IMT group. IMT attenuated the reduction of oxygen saturation in intercostal and forearm muscles and the increase in blood lactate during respiratory fatigue (P <.001 and P <.05, respectively). These changes were different from the control group (P <.01, P <.05, and P <.05, respectively). After 8 weeks, similar increases in oxygen consumption, mean arterial pressure, heart rate, stroke volume, and cardiac output were observed in both groups during respiratory fatigue. CONCLUSIONS: This randomized controlled clinical trial demonstrates that IMT attenuates the respiratory muscle oxygen demand-delivery mismatch during respiratory fatigue in patients with chronic HF.

Pneumomediastinum and the aortic nipple: the clinical relevance of the left superior intercostal vein.

This article discusses the appearance of the "aortic nipple" in chest radiography, and reviews the embryology and anatomy of the left superior intercostal vein which causes the appearance of an "aortic nipple." This radiological sign is useful in differentiating certain thoracic pathologies, such as pneumomediastinum, pneumopericardium, and medial pneumothorax. Pneumomediastinum is an encompassing term describing the presence of air in the mediastinum, and may arise from a wide range of pathological conditions. Despite the well-described imaging of pneumomediastinum, it is sometimes difficult to differentiate from other conditions such as pneumopericardium and medial pneumothorax. A separate finding, "aortic nipple" is the radiographic term used to describe the lateral nipple-like projection from the aortic knob present in a small number of individuals. The aortic nipple corresponds to the end-on appearance of the left superior intercostal vein coursing around the aortic knob, and may be mistaken radiologically for lymphadenopathy or a neoplasm. Despite their relative independence, the aortic nipple is defined by new contours in cases of pneumomediastinum, taking on an "inverted aortic nipple" appearance. In this position, the inverted aortic nipple may facilitate radiographic discrimination of pneumomediastinum from similar conditions. This study aims to review the common clinical and radiographic features of both pneumomediastinum and the aortic nipple. The radiologic appearance of the aortic nipple occurring in unison with pneumomediastinum, and its potential role as a tool in the differentiation of pneumomediastinum from similarly presenting conditions will also be described.

Size of the collateral intercostal artery in adults: anatomical considerations in relation to thoracocentesis and thoracoscopy.

No detailed descriptions exist of the collateral intercostal artery which can provide an accurate anatomical basis for ensuring a low rate of vascular complications during thoracocentesis and thoracoscopy. Consequently the present study was undertaken to provide information on the origin, size and topographic relationships of the collateral intercostal artery. Ninety cadaveric adult intercostal spaces were dissected using standard procedures. The collateral intercostal arteries were exposed throughout their full length and measured at the points within the intercostal spaces considered to be the most important for clinical purposes. The posterior intercostal arteries and their collateral branches were observed to decrease in size from posterior to anterior; however, no significant differences were present in their size in the first four intercostal spaces. Based on these findings the usual thoracocentesis or thoracoscopy technique, in which it is recommended that puncture is done as close as possible to the superior margin of the inferior rib, may lead to collateral intercostal artery laceration and considerable bleeding. A subtle, but important, modification to this technique is suggested aimed at achieving safer access to the intercostal space. In the modified technique, the puncture should be made in the middle of the intercostal space, thereby reducing the possibility of laceration of the collateral intercostal artery.