Washout of protein in dog lung lymph.

After an increase in microvascular filtration rate, lung lymph may contain protein washed from the tissue spaces plus protein from the filtrate. If so, then the lymphatic protein concentration may be significantly higher than the filtrate protein concentration (Cf). To test this hypothesis, we decreased the plasma protein concentration from 5.1 +/- 0.6 to 0.54 +/- 0.15 g/dl and increased the pulmonary microvascular filtration rate in four dogs. We estimated Cf to be 0.16 +/- 0.05 g/dl after we reduced the plasma protein concentration, and the lymphatic protein concentration (0.43 +/- 0.04 g/dl) was significantly greater than Cf. Our results indicate that lung microvascular membrane reflection coefficients estimated from lung lymph data may be too low. However, the amount of error caused by tissue protein washout is probably small. To account for the protein washout error, we estimated the lung microvascular membrane reflection coefficient to be approximately 0.74-0.76 instead of the approximately 0.70 previously reported for dogs (J. C. Gabel et al. J. Appl. Physiol. 55: 866-869, 1983).

Acute injury and chronic disability resulting from surfboard riding.

We undertook a cross-sectional survey of surfers at eight Victorian beaches between February and May 2003 and analysed acute injury and chronic disability sustained while surfing during the preceding 12 months. Significant injuries were defined as requiring medical attention or time off surfing/work. 646 surfers were enrolled (90.2% male, median age 27 years, median years of surfing 10). 145 surfers sustained 168 significant acute injuries in the preceding 12 months (0.26 injuries/surfer/year, 95% CI 0.22-0.30). Most were caused by striking a surfboard or another surfer (45.2%, 95% CI 37.6-53.1), "wiping out" (36.3%, 95% CI 29.1-44.1) or striking the seabed (17.9%, 95% CI 12.6-24.7). Injuries included lacerations (46.4%, 95% CI 38.8-54.3), sprains (28.6%, 95% CI 22.0-36.1), dislocations (10.7%, 95% CI 6.7-16.6) and fractures (8.9%, 95% CI 5.3-14.6). Body parts most frequently injured were the lower limb (45.8%, 95% CI 38.2-53.7) and the head/face (26.2%, 95% CI 19.9-33.6). Surfing injuries that were treated in Victorian emergency departments over a six year period revealed a similar pattern, although there was a greater proportion of head/face injuries (42.0%, 95% CI 36.0-48.1, p = 0.001). 20 surfers reported long-term effects from acute injuries, mainly unstable/stiff/painful joints. 136 surfers reported chronic health problems not related to acute injury including chronic/recurrent otitis externa and exostoses, muscle and joint pain/stiffness and pterygium. Significant injury while surfing is not uncommon. Although head injury accounts for a considerable proportion, very few surfers wear protective headgear. Greater use of protective headgear should be considered.

Estimation of lymph flow by relating lymphatic pump function to passive flow curves.

Active pumping in postnodal lymphatic vessels is an important factor influencing lymph flow. However, the output of the lymphatic pump also depends on the rate of flow into the pump. This arrangement is similar to the blood circulation where cardiac output depends on the rate of blood flow through the veins into the heart (venous return) and on the pumping characteristics of the heart itself (cardiac function curves). One common way to analyze the blood circulation rate is to interrelate venous return and cardiac function curves. In this study, we used a similar technique to analyze lymph flow. We used lymphatic flow vs. outflow pressure (passive flow) relationships for nonpumping lymphatics to represent the inflow of lymph to the lymphatic pump. We used data on the pumping characteristics of postnodal lymphatic vessels to generate relationships between lymphatic pump outflow and pump inflow pressure (pump function curves), and then interrelated these curves. The results were not only similar to previously measured lymph flow data obtained from experimental animals, but also support the observation that under normal circumstances lymph flow is periodic and in surges (active pumping) but in edematogenic states lymph flows more continuously (i.e., passively).

Pulmonary hemorrhage in association with negative pressure edema in an intubated patient.

Negative pressure pulmonary edema due to upper airway obstruction following extubation is a well-recognized problem. However, frank pulmonary hemorrhage as a manifestation of upper airway obstruction is uncommon. We report a case of significant pulmonary hemorrhage and negative pressure pulmonary edema in an intubated patient. Bronchoscopy showed a collection of blood in the right lower lobe of the lungs, suggesting a localized source of bleeding. There have been two previously reported cases of pulmonary hemorrhage after upper airway obstruction. One suggested that the bleeding was due to damage to the pulmonary capillaries, the other that it was due to disruption of the bronchial vessels. We feel that in our case there was some indication that the pulmonary bleeding was a result of bronchial vessel damage. A number of factors might have been involved in its development, including negative pulmonary pressure, recent respiratory tract infection, and positive airways pressure (due to coughing).