Summary Donor shortage urges optimal use of all lungs available. Ex vivo lung perfusion (EVLP) is a method to evaluate lung function before implantation. EVLP was performed in pigs to evaluate lung function, using two different clinical non‐heart‐beating (NHS) donor protocols: flush perfusion and topical cooling after 1‐h warm ischaemia (n = 5 each). Secondly, we investigated whether EVLP can be used for 6 h ex vivo machine preservation (n = 4). In comparison with topical cooling, flush perfusion preserved lung function better during EVLP. During 6 h normothermic EVLP, gas exchange remained stable; however, the pulmonary artery pressure and ventilation pressure showed a significant increase. EVLP is a reliable method for evaluation of lung graft function. Flush perfusion with Perfadex is preferred above topical cooling in NHB lung donation. Six‐hour normothermic EVLP is feasible but should be further improved to make ex vivo machine preservation or treatment of lung grafts successful.

IntroductionOperations for scoliosis are designed to correct the deformity and to prevent its progression by achieving a solid fusion. In 1962, Harrington introduced the use of spinal instrumentation for the surgical treatment of scoliosis [16]. In the 1980s, the development of spinal instrumentation expanded considerably. New anterior and posterior systems were introduced [2,6,10,12,18,32]. With these advanced segmental systems, better corrections are possible in the coronal and the sagittal plain in comparison with Harrington instrumentation. However, the literature is contradictory on the effect on axial rotation and rib cage deformity. In most literature it is suggested that axial plane correction is limited [13,19,21,33].Abstract The biocompatibility and functionality of a new scoliosis correction device, based on the properties of the shape-memory metal nickel-titanium alloy, were studied. With this device, the shape recovery forces of a shape-memory metal rod are used to achieve a gradual threedimensional scoliosis correction. In the experimental study the action of the new device was inverted: the device was used to induce a scoliotic curve instead of correcting one. Surgical procedures were performed in six pigs. An originally curved squared rod, in the cold condition, was straightened and fixed to the spine with pedicle screws. Peroperatively, the memory effect of the rod was activated by heating the rod to 50°C by a low-voltage, high-frequency current. After 3 and after 6 months the animals were sacrificed. The first radiographs, obtained immediately after surgery, showed in all animals an induced curve of about 40°Cobb angle -the original curve of the rod. This curve remained constant during the followup. The postoperative serum nickel measurements were around the detection limit, and were not significantly higher compared to the preoperative nickel concentration. Macroscopic inspection after 3 and 6 months showed that the device was almost overgrown with newly formed bone. Corrosion and fretting processes were not observed. Histologic examination of the sections of the surrounding tissues and sections of the lung, liver, spleen and kidney showed no evidence of a foreign body response. In view of the initiation of the scoliotic deformation, it is expected that the shape-memory metal based scoliosis correction device also has the capacity to correct a scoliotic curve. Moreover, it is expected that the new device will show good biocompatibility in clinical application. Extensive fatigue testing of the whole system should be performed before clinical trials are initiated.

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ABSTRACT. Transmission pulse oximetry is used for monitoring in many clinical settings. However, for fetal monitoring during labor and in situations with poor peripheral perfusion, transmission pulse oximetry cannot be used. Therefore, we developed a reflectance pulse oximeter, which uses the relative intensity changes of the reflected red and infrared light (redlinfrared ratio) to measure the arterial oxygen saturation. The performance of the reflectance pulse oximeter was studied in acute experiments in fetal lambs. By stepwise reduction of the inspired oxygen concentration of the ewe, measurements were done at the fetal scalp at various arterial oxygen saturation levels (17-82%). Reflectance pulse oximeter readings were averaged over periods of 15 s and compared with simultaneously taken fetal arterial blood samples. A calibration curve for the relationship between redlinfrared ratio and arterial oxygen saturation was obtained from 53 measurements in four fetal lambs, by linear regression analysis [redlinfrared = 4.088 -(0.038 -Saoz), r = 0.961. In these experiments, the pulse oximeter showed a precision of 4.7% oxygen saturation around the calibration curve, with a 95% confidence interval of f 9.4%. (Pediatr Res 31: [266][267][268][269] 1992) Abbreviations R/IR, redlinfrared Sao2, arterial oxygen saturation LED, light-emitting diode Fioz, fraction of inspired oxygen Pao2, arterial oxygen pressure Pulse oximetry provides continuous, noninvasive monitoring of Sao2 (1, 2). The method uses the pulsatile changes of red and infrared light transmitted through tissue to estimate arterial oxygenation. In adults, light transmission is usually measured through the finger, toe, ear, or nose. In newborns, light transmitted through the hand or foot is used for pulse oximetry. Limitations in accessible measurement sites due to circulatory problems and artefacts caused by motion impair the use of transmission pulse oximetry. With the fetal head as the presenting part, light transmission cannot be used for fetal pulse oximetry during labor. For this purpose a pulse oximeter that measures reflected light is required. This can be achieved by modifying commercially available transmission probes into reflectance probes, which have been used recently for studies in the human fetus during labor (3,4).In healthy adults, most pulse oximeters provide reliable and 261 accurate estimates of Sao2. However, it remains to be seen if pulse oximetry in the fetus is as accurate as in the adult. First, the influence of scattering is much more pronounced in the reflectance mode than it is in transmission (5-7). Second, the currently available pulse oximeters show a considerable decrease in accuracy at Sao2 below 70% (S), which is the predominant range in the fetus during labor. Finally, previous studies have shown that fetal scalp blood flow is markedly reduced in the course of labor (9-1 1). As a consequence, the pulse wave is likely to diminish, decreasing the signal to noise ratio, which causes a decrease in accuracy. For these reasons, ...