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Reactive oxygen species are constantly formed in biological systems. When production exceeds antioxidant protection, oxidative stress leading to molecular damage occurs. The most reactive ROS in biological systems is the hydroxyl radical which damages adjacent molecules at diffusion controlled rates. The possibility of preventing such chemistry inside cells with therapeutic doses of mannitol at present seem remote.

Results-Preoperatively: long axis function was abnormal compared with that in normal controls. In systole total long axis excursion and peak shortening rate were reduced, onset of shortening delayed, and there was pre-ejection lengthening (P < 0.001). In diastole there was abnormal shortening during isovolumic relaxation, delaying the onset oflong axis lengthening (P < 0.001). Peak lengthening rate was also reduced and A wave excursion increased (P < 0.001). Transmitral Doppler showed increased A wave velocity and reduced peak E/A diastolic flow velocities ratio (P < 0.001). Intraoperatively: preclamping results did not differ from those before operation. With clamping the extent of systolic and diastolic abnormalities promptly increased as to a lesser extent did those of transmitral flow velocity, although heart rate and blood pressure did not change significantly. Total long axis excursion and A wave amplitude were more reduced by aortic than iliac clamping, whereas the onset of lengthening was more delayed and the lengthening velocity more reduced with iliac clamping. Some 5 min after unclamping systolic long axis function had already returned towards normal; total excursion increased, as did the peak shortening rate, and the onset of shortening became less delayed (P < 0.001). In diastole the delayed onset of lengthening regressed, its lengthening velocity increased, and A wave excursion feli (P < 0-001). Early diastolic transmitral flow velocity also increased. This improvement in systolic and diastolic long axis function had progressed 15 min after unclamping but showed no further change at 5 days. At 5 days after operation, however, systolic and diastolic measurements had improved compared with those preoperatively.

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Lung volume reduction surgery can improve lung function in patients with emphysema. We report our anaesthetic experience, problems and the physiological data of eight patients. Our aims were prevention of air trapping and air leaks, good analgesia and early recovery and mobilization. We were able to achieve these aims using pressure limited ventilation, lumbar epidural diamorphine, propofol infusions and intensive physiotherapy. Hypoxia during one-lung ventilation was the main intraoperative problem. Air leaks, infection and pulmonary hypertension were the main postoperative problems.