Hemodynamic and cerebral repercussions arising from surgical interruption of the superior vena cava. Experimental model.

This study was designed to analyze the hemodynamic and cerebral repercussions arising from the surgical interruption of the superior vena cava. The experiments were carried out in 12 mongrel dogs under two different conditions: with shunt (group A, n = 6) and without the installation of a shunt (group B, n = 6). The period of occlusion was 35 minutes. The right atrium pressure, pulmonary arterial pressure, and aortic pressure are not significantly modified in the two groups. The intracranial pressure had an important correlation with the central venous pressure (r2 = 0.8572). In group B, the intracranial pressure had a sharp increase between the basal period (6.9 +/- 1.47 mm Hg) and the clamping superior vena cava (17.2 +/- 1.05 mm Hg), accentuated with the interruption of the azygous vein (32.2 +/- 0.7 mm Hg). In group A, the use of a shunt avoided this alteration during clamping of the superior vena cava (6.8 +/- 2.0 mm Hg) and the azygous vein (8.0 +/- 2.24 mm Hg). However, after removal of the clamps in group B, an elevated residual intracranial pressure was observed (21.1 +/- 3.33 mm Hg) in contrast to the central venous pressure, which returned to the basal values (4.4 +/- 0.7 mm Hg). The biomechanic findings of the volume-pressure curves (with Miller and Marmarou-Shapiro tests) and the cerebral necropsy showed brain damage in group B, without the shunt. Three animals had areas of hemorrhagic infarction. Histologic study demonstrated signs the incipient vasogenic edema. In group A, all findings were compatible with the normal. In conclusion, these results suggest the importance of shunting the blood in those cases of a nonobstructed superior vena cava because the clamping and reconstruction produce hemodynamic compromise and brain damage.

The influence of large decompressive craniectomy on the outcome of surgical treatment in spontaneous intracerebral haematomas.

The outcome of a series of 73 patients with spontaneous intraparenchymatous haematomas treated by surgical evacuation of the clot and decompressive craniectomy has been described. Comparing postoperative mortality of this series with another series of patients (54 cases) treated only with surgical removal of the clot without decompressive craniectomy a statistically significant improvement in the mortality rate after craniectomy could be observed in acute cases demanding surgical intervention for preservation of life in the first 24 hours. If signs of brain-stem suffering appear surgical mortality increases proportionally to the duration of this symptomatology. In these cases surgery, if it is to be useful, has to be performed as soon as possible. The morbidity of the surviving patients is not greater in this series with decompressive craniectomy than in series without decompression.

Pyocephalus of the newborn child.

3 cases of pyocephalus (ventricular empyema) in newborn children are described and 16 cases from the literature are analyzed. Half of the previously published cases of pyocephalus are secondary to cerebral abscesses. Neuroradiological findings and especially the necroscopic study of a case demonstrated the existence of membranous blockages inside the ventricles which may make the circulation of CSF impossible. Our treatment of choice consists of repeated punctures and evacuations of purulent content and topic as well as parenteral administration of antibiotics. Further CSF derivative measures are almost always necessary. By these means, we believe the high mortality of these cases could be lowered.