Neutrophil accumulation in alveolar spaces is a conspicuous finding in hyperoxia-exposed lungs. We hypothesized that xanthine oxidase (XO)-derived oxidants contribute to retention of neutrophils in hyperoxic lungs. Rats were subjected to normobaric hyperoxia (100% O2) for 48 h, and lungs were assessed for neutrophil sequestration (morphometry and lavage cell counts) and injury (lavage albumin levels and lung weights). In rats exposed to hyperoxia, we found increased (P < 0.05) lung neutrophil retention, lavage albumin levels, and lung weights compared with normoxia-exposed control rats. Suppression of XO activity by pretreatment with allopurinol decreased (P < 0.05) lung neutrophil retention but increased (P < 0.05) lavage albumin concentrations and lung weights in hyperoxic rats. Allopurinol treatment had no effect (P > 0.05) on the numbers of macrophages or lymphocytes recoverable by lung lavage. Depletion of XO activity by an independent method, tungsten feeding, also decreased (P < 0.05) lung lavage neutrophil counts and increased (P < 0.05) lavage albumin concentrations. We conclude that XO may be involved in lung neutrophil retention but not lung injury during exposure to hyperoxia.

The role of smoke particles in the pathogenesis of smoke inhalation lung injury is enigmatic. We

Background: The increased use of the radial artery for coronary artery bypass conduits has heightened the awareness of potential resultant hand ischemia. The Allen test and subsequent modifications have been used to evaluate the patency of the superficial palmar arch (SPA). The purpose of this study was to determine if changes in blood flow patterns of the SPA assessed by the modified Allen test parallel changes in blood pressures of the first and second digits following radial artery occlusion. Methods: Continuous-wave Doppler ultrasound and photoplethysmography (PPG) were used to evaluate blood flow in the SPA and first and second digits, respectively, before and after manual occlusion of the radial artery in 60 extremities. A second continuouswave Doppler probe was used to ensure complete occlusion of the radial artery. Digit skin temperature was controlled between 36° and 37.5°0. A reduction of >20 mmHg in blood pressure was arbitrarily chosen to reflect a clinically significant change in digit arterial pressure. Results: Six of the 60 extremities (10%) studied showed a decrease in the audible Doppler signal over the SPA following radial artery occlusion. Reduction in digit arterial pressure following radial artery occlusion occurred in 13 of 60 extremities (21.7%). Digit arterial pressure reductions ranged from 20 to 58 mmHg (mean ±SD, 35.2 ±12.8 mmHg), demonstrating a 40% decrease in digital pressure. Changes in SPA flow did not parallel digital pressure changes following occlusion of the radial artery. Conclusion: Continuous-wave Doppler ultrasound of the SPA following radial artery compression alone does not accurately predict digit ischemia. Digit arterial pressure measurement of the first and second digits of upper extremities offers a relatively simple and objective method for evaluation of potential ischemic complications following radial artery harvest. This finding is important because many physicians only use a modified Allen test with radial artery compression to assess potential digit ischemia.

The minimal incidence of pulmonary foreign-body embolism in a general pediatric pathology experience was ascertained by reviewing autopsy records, and the true incidence of pulmonary foreign-body embolism was determined by studying lung sections from 64 autopsies of patients who had undergone cardiac procedures. Seventeen cases of embolism were reported from 370 autopsies, an incidence of 4.6%. The true incidence of pulmonary foreign-body embolism was found to be 21.9% in the cardiac surgical autopsies and the minimal incidence was 5.1% in patients who had other types of surgery. No patients other than those having surgical procedures had embolism. Hair was found to be the embolic material in 35% of cases. Embolic lesions were characterized, staged, and correlated with clinical data. The pathogenesis of this condition is unclear, but it probably involves contamination of surgical materials with particulate matter.