William E. Holden

Adult intrapulmonary and mediastinal lymphangioma causing haemoptysis.

A 54 year old man, an ex-smoker, was noted to have a right hilar mass five years before presentation at our hospital. Thoracotomy had shown a cystic mass (benign lymphangiomatous cyst on frozen section) enveloping the structures of the right hilum. Resection was not attempted because a pneumonectomy would have been required. A radiograph four years later showed no change. One month before admission to our hospital he developed a cough and haemoptysis of 30-40 ml a day. Physical examination and laboratory studies revealed no abnormality apart from microcytic anaemia (haemoglobin 11 9g/dl). Radiologically (fig 1) the mass was larger and contained several air-fluid levels. Fibreoptic bronchoscopy showed distortion and circumferential compression of all lobar and segmental airways ofthe right lung. Pulmonary angiography showed extrinsic compression of pulmonary arteries and veins; there was no evidence of a systemic arterial supply to the cystic lesion on aortography. Computed tomography with intravenous enhancement by contrast medium showed a multilobulated mass with several air-fluid levels and extrinsic compression of right bronchi, pulmonary arteries, and veins. Venous emptying was delayed. The mediastinal structures were normal. Because of continued haemoptysis, a right pneumonectomy was performed. At operation a cystic structure was found, intertwined with and enveloping right hilar structures. A cystic appearing lymph node (3 5 x 1 9 x 1-4 cm), not contiguous with the intrapulmonary mass, was resected from the azygous vein and paratracheal area of the mediastinum. In the excised lung multiple cysts (up to 5 cm diameter), many filled with blood clot, were embedded in the hilum and the perihilar parenchyma. The basilar segments of the right lower lobe showed intra-alveolar haemorrhage and haemosiderin laden macrophages. The cysts were lined by flattened endothelium and had varying degrees of

Endothelium-dependent effects of cigarette smoke components on tone of porcine intrapulmonary arteries in vitro☆

The acute effects of cigarette smoking on the pulmonary vasculature are poorly understood--both vasodilatory and vasoconstrictive effects have been described. To investigate the mechanisms involved, strips of pig intrapulmonary arteries with and without intact endothelium were exposed to an extract of cigarette smoke made by bubbling smoke through phosphate-buffered saline. After contraction with norepinephrine (2.5 X 10(-7) M), smoke extract (concentration range 0.001 to 0.5%) caused a biphasic response in strips with intact endothelium--relaxation at lower concentrations and contraction at higher concentrations. Both relaxation and contraction responses were absent in strips without endothelium. Blockade of muscarinic, beta adrenergic, serotonergic, and histamine type 1 and 2 receptors did not alter the effects. Indomethacin (5 X 10(-6) M) or acetylsalicylic acid (10(-4) M) blocked the relaxation but not contraction effects of smoke extract, suggesting that relaxation was due to cyclooxygenase products of arachidonic acid. Nicotine caused endothelium-dependent contraction of intrapulmonary arteries and the contractile effects of both nicotine and smoke extract were blocked by hexamethonium (10(-6) M). However, the contractile effects of cigarette smoke components are more potent than those of nicotine. These findings help explain previously described acute effects of smoking on the pulmonary vasculature and provide insight into the mechanisms involved.

Extralobar pulmonary sequestration presenting as a mediastinal malignancy.

Pulmonary sequestration is an uncommon congenital anomaly usually diagnosed in childhood. It frequently presents as a lower lobe mass with symptoms from vascular shunting, anatomic impingements, or associated anatomic defects. This case report describes an adult with asymptomatic extralobar sequestration involving the mediastinum and left upper lobe. The unusual location and radiographic appearance, suggestive of malignancy, led to prompt surgical exploration. We review the literature on this topic, focusing on anatomic variability and difficulties with preoperative diagnosis.

Exhaled nasal nitric oxide output is reduced in humans at night during the sleep period

The physiologic function of nasal nitric oxide (NO) release is unknown. In prior experiments, topical NG-nitro-L-arginine methyl ester (L-NAME) on nasal mucosa reduced exhaled nasal NO output and caused daytime sleepiness. We hypothesized that nasal NO output is reduced at night during the sleep period. We measured exhaled nasal NO concentration and minute ventilation and calculated nasal NO output in humans over 24 h. Daytime awake NO output was greater than NO output at night during sleep or transient wakefulness. Exhaled NO concentration decreased during sleep along with minute ventilation. A daytime voluntary reduction in minute ventilation also decreased nasal NO output but exhaled NO concentration increased. Nasal NO output was not changed by body position. We conclude that exhaled nasal NO output is decreased at night due to decreased mass flow of NO into nasal air in addition to decreased minute ventilation. Our findings suggest a role of nasal NO in sleep or in the physiologic processes accompanying sleep.

Direct coextensive plethysmography for non-invasive measurement of systemic pressures and volumes

A method for noninvasive measurement of pressures and fluid volumes of the complete systemic vascular circuit, called direct coextensive plethysmography, is proposed. This includes the pressures of the large veins, small veins, venules, capillaries, arterioles, small arteries, large arteries and nonvascular fluid compartments. It uses a conventional pressure cuff on the outside of the arm, combined with a tetrapolar bioimpedance electrode band to derive a fluid volume indication (impedance) versus pressure profile for the entire system. Determination of state changes in the residual fluid volume versus pressure profile yields physiologic information about the pressures and fluid volumes in the various segments of the vascular circuit and nonvascular fluid compartments. Advanced signal processing techniques have been applied to improve upon early slope change analysis. Initial confirmation of the correlation between the measured large vein pressure and the central venous pressure were made in a small clinical trial with intensive care unit subjects.