Use of the Oto lung donor score to analyze the 2010 donor pool of the Nord Italia Transplant program.

INTRODUCTION: The feasibility and utility of a lung donor score that has been recently proposed was tested among a pool of lung donors referred to the Nord Italia Transplant program (NITp) organ procurement organization. MATERIAL AND METHODS: Each lung donor was assigned an Oto score including, age, smoking history, chest X-ray, secretions and ratio of arterial oxygen tension to inspired oxygen fraction (PaO(2)/FiO(2)). Based on clinical compromise, each variable received a score between 0 and 3, except for PaO(2)/FiO(2), which was scored between 0 and 6 given its overall relevance. RESULTS: Throughout 2010, 201 multiorgan donors were initially considered to be potential lung donors. Among these, 59 (29.4%) eventually yielded 67 lung transplantations (named "Used group"). Among the 142 (70.6%) refused lungs, 28 were not used due to logistic or medical problems ("general exclusion" group, GE) and 114, because of poor lung function ("lung exclusion" group, LE). Median lung donor scores were 1 (range, 0 to 3), 4 (range, 2.5 to 6.5), and 7 (range, 5 to 9) in the Used, GE, and LE groups, respectively (one-way analysis of variance, P < .001). Some donors with Oto scores ≤7 worsened over time so that the score had significantly increased by the time of organ retrieval. Overall, subjects who died after lung transplantation were characterized by higher lung donor scores, (2 [1-4] versus 0.5 [0-3], P = .003). CONCLUSION: Our analysis suggested that the use of a donor score as a dynamic tool over the donation process was of great utility to describe and analyze a pool of lung donors.

Direct and indirect bacterial killing functions of neutrophil defensins in lung explants.

Studies of the antimicrobial activity of neutrophil defensins have mostly been carried out in microbiological media, and their effects on the host defense in physiological conditions are unclear. We examined 1) the antibacterial activity of defensins in physiological media with and without lung tissue present, 2) the effect of defensins on hydrogen peroxide (H(2)O(2)) production by lung tissue that had been exposed to bacteria, and 3) the effect of diphenyleneiodonium (DPI), an inhibitor of reactive oxygen species formation, on the antibacterial activity of defensins in the presence of lung tissue. Defensins were incubated with Escherichia coli or Pseudomonas aeruginosa in the absence or presence of primary cultured mouse lung explants. Defensins reduced bacterial counts by approximately 65-fold and approximately 25-fold, respectively, at 48 h; bacterial counts were further decreased by approximately 600-fold and approximately 12,000-fold, respectively, in the presence of lung tissue. Defensins induced H(2)O(2) production by lung tissue, and the rate of killing of E. coli by defensins was reduced by approximately 2,500-fold in the presence of 10 microM DPI. We conclude that defensins exert a significant antimicrobial effect under physiological conditions and that this effect is enhanced in the presence of lung tissue by a mechanism that involves the production of reactive oxygen species.

An improved in vivo rat model for the study of mechanical ventilatory support effects on organs distal to the lung.

OBJECTIVE: To study the influence of different mechanical ventilatory support strategies on organs distal to the lung, we developed an in vivo rat model, in which the effects of different tidal volume values can be studied while maintaining other indexes. DESIGN: Prospective, randomized animal laboratory investigation. SETTING: University laboratory of Ospedale Maggiore di Milano-Instituto di Ricovero e Cura a Carattere Scientifico. SUBJECTS: Anesthetized, paralyzed, and mechanically ventilated male Sprague-Dawley rats. INTERVENTIONS: Two groups of seven rats each were randomized to receive tidal volumes of either 25% or 75% of inspiratory capacity (IC), calculated from a preliminary estimation of total lung capacity. Ventilation strategies for the two groups were as follows: a) 25% IC, 9.9+/-0.8 mL/kg; frequency, 59+/-4 beats/min; positive end-expiratory pressure, 3.6+/-0.8 cm H2O; and peak inspiratory airway pressure (Paw), 13.2+/-2 cm H20; and b) 75% IC, 29.8+/-2.9; frequency, 23+/-13; positive end-expiratory pressure, 0; peak inspiratory Paw, 29.0+/-3. MEASUREMENTS AND MAIN RESULTS: Mean arterial pressure (invasively monitored) remained well above adequate perfusion pressure values throughout, and no significant difference was seen between the two groups. PaO2, pHa, and PaCO2 values were compared after 60 mins of ventilation and again, no significant difference was seen between the two groups (PaO2, 269+/-25 and 260+/-55 torr; pHa, 7.432+/-0.09 and 7.415+/-0.03; PaCO2, 35.4+/-8 and 32.5+/-2 torr, for the 25% IC and 75% IC groups, respectively). Mean Paws were not different (6.4+/-0.8 cm H2O in the 25% IC groups, and 6.1+/-1.2 in the 75% IC groups, respectively). At the end of the experiment, animals were killed and the liver and kidney isolated, fixed in 4% formalin, cut, and stained for optic microscopy. Kidneys from rats ventilated with 75% IC showed increased Bowman's space with collapse of the glomerular capillaries. This occurred in a greater percentage of rats ventilated with 75% IC (0.67+/-0.2 vs. 0.29+/-0.2, 75% IC vs. 25% IC, respectively; p < .05). Perivascular edema was also present in rats ventilated with 75% IC (p < .05). Morphometric determinations of the empty zones (index of edema) demonstrated a trend toward differences between 75% IC livers and 25% IC (0.14+/-0.05 vs. 0.11+/-0.02, respectively). CONCLUSION: We conclude that it is possible to study the effects of mechanical ventilatory support on organs distal to the lung by means of an in vivo rat model.