Ventilator autotriggering : An underestimated phenomenon in the determination of brain death.

BACKGROUND: Ventilator autotriggering (VAT) may induce uncertainty in diagnosing brain death because it may falsely suggest a central respiratory drive in brain-dead patients where no intrinsic respiratory efforts exist. Since the lack of international standardization of brain death criteria contributes to the loss of potential donor organs, it is important to be aware of this phenomenon, which is a not well-known confounder in the process of diagnosing brain death. METHODS: The national official recommendations or guidelines for the determination of brain death and organ transplantation of 15 selected European countries (including all 8 member states of the Eurotransplant network) were evaluated with respect to VAT. In addition, a literature search (PubMed, Google Scholar) using the term "ventilator autotriggering", synonyms or similar content-related wording was carried out. RESULTS: The VAT phenomenon was mentioned in 3 of the 15 official recommendations and guidelines on diagnosing brain death. The causes and management of VAT are presented in different ways in the reviewed official recommendations and guidelines. CONCLUSION: The phenomenon of VAT is inconsistently addressed in the national guidelines and recommendations for the determination of brain death and should, therefore, be included in future harmonized brain death codes. Detection and correction of VAT should be implemented as early as possible by a structured procedure. Additional training and information on this phenomenon should be made available to the entire intensive care unit staff.

Significant association of the interleukin-6 gene polymorphisms C-174G and A-598G with type 2 diabetes.

Elevated blood concentrations of IL-6 have been shown to predict type 2 diabetes. Because the impact of IL-6 gene polymorphisms on diabetes status, parameters of the metabolic syndrome, and low-grade systemic inflammation has not been analyzed in a population-based study, we investigated the association of the IL-6 single nucleotide polymorphisms C-174G and A-598G on these parameters in 704 elderly participants of the Kooperative Gesundheitsforschung im Raum Augsburg/Cooperative Research in the Region of Augsburg (KORA) Survey 2000. Both -174G and -598G alleles were significantly associated with type 2 diabetes (-174G: odds ratio = 1.51, 95% confidence interval = 1.11-2.07, P = 0.0096; -598G: odds ratio = 1.56, 95% confidence interval = 1.13-2.15, P = 0.0069) but not with impaired glucose tolerance. In subgroup analyses, the association reached statistical significance in men and in leaner subjects (body mass index

Metastatic patterns of prostate cancer: an autopsy study of 1,589 patients.

The prognosis of prostate cancer is mainly determined by the presence or absence of metastases. Nevertheless, the metastatic pathways in prostate cancer are not entirely understood. Among 19,316 routine autopsies performed from 1967 to 1995 on men older than 40 years of age, the reports from those 1,589 (8.2%) with prostate cancer were analyzed. Hematogeneous metastases were present in 35% of 1,589 patients with prostate cancer, with most frequent involvement being bone (90%), lung (46%), liver (25%), pleura (21%), and adrenals (13%). Several lines of evidence suggested the existence of a backward metastatic pathway through veins from the prostate to the spine in addition to classical hematogeneous tumor spread via the vena cava. First, there was an inverse relationship between spine and lung metastases, suggesting that metastasis to the spine is independent of lung metastasis. Second, the maximum frequency of spine involvement occurred in smaller tumors (4 to 6 cm) as compared with the maximum spread to lung (6 to 8 cm) and liver (>8 cm), suggesting that spine metastases precede lung and liver metastases in many prostate cancers. Third, there was a gradual decrease in spine involvement from the lumbar to the cervical level (97% v 38%), which is consistent with a subsequent upward metastatic spread along spinal veins after initial lumbar metastasis. The results of this study show that bone, lung, and liver are the most frequent sites of distant prostate cancer metastases. Besides the cava-type of metastasis through lung passage, there are strong arguments for the existence and clinical significance of a backward venous spread to the spine, which is likely to occur early in the metastatic process.

Fat embolism and death during prophylactic osteosynthesis of a metastatic femur using an unreamed femoral nail.

We report a case of cardiovascular collapse and death occurring intraoperatively during the prophylactic nailing of a metastatic femur using an unreamed femoral nail. The cause of death, as documented by the autopsy, was a massive fat embolism. The risk of fat embolism while performing intramedullary nailing is well known and has been linked to the process of medullary reaming. Unreamed femoral interlocking nails recently have become available. Although recent reports in the literature have concluded that the risk of fat embolism appears less likely while using unreamed implants, the surgeon should carefully consider the indications for any type of intramedullary fixation, particularly when dealing with unbroken femurs exhibiting impending pathologic fracture, or when preexisting pulmonary disease such as metastasis is present.

Comparison of torsional strength of humeral intramedullary nailing: a cadaveric study.

Control of rotation after intramedullary fixation of the humeral shaft has been observed to vary clinically. Two of the newer intramedullary nails specifically designed for the humerus were tested. Transverse and spiral fractures were created in 35 fresh-frozen cadaveric humeri. The constructs were tested in a materials testing system to evaluate in vitro the torsional strength of the nailed humeral fractures. Intact bones showed a mean peak torque of 53 +/- 17 Nm. The humeri fixed with the Russell-Taylor nail (n = 18) using one interlocking screw proximally and one distally showed a mean torsional strength of 10.4 +/- 3.6 Nm. The specimens fixed with the Seidel nail (n = 17), interlocked proximally with two screws and distally by the friction of three expanded flanges against the inner cortex, had a significantly lower mean torsional strength of 1.5 +/- 0.6 Nm (p < 0.0005). When compared with intact bones, constructs using the Russell-Taylor nail achieved 20% of mean peak torque. This improved rotational strength should permit an earlier return to full functional use of the extremity.

Biomechanical comparison of methods of fixation of isolated osteotomies of the posterior acetabular column.

Ten fresh frozen specimens of a hemipelvis, including the hip joint, capsule and proximal femur, from elderly cadavers were used to evaluate three methods of internal fixation of isolated posterior column osteotomies. Intact and reconstructed specimens were tested at 30 degrees and 60 degrees of hip flexion in a specially designed joint simulator. The three methods of fixation used were a single 3.5 mm reconstruction plate, two such plates, and a 4.5 mm lag screw with a single plate. Motion at the fracture site in three orthogonal directions, and the overall stiffness of the construct, were recorded simultaneously. No significant differences were noted in stiffness for the three procedures and all retained 80% of the intact stiffness. At 60 degrees of flexion, smaller interfragmentary compliances were allowed by fixation with a lag screw and a neutralisation plate (p < 0.05). At 30 degrees, the position of the load plane relative to the fracture plane allowed less interfragmentary motion, so that no significant differences were found between the 3 methods.

Cerclage wiring in internal fixation of acetabular fractures.

In the last 100 fractures of the acetabulum surgically treated in our institution, cerclage wires have been used as a reduction tool in 14 patients. In each case the fracture pattern affected both columns, and nine of them were approached through a single ilioinguinal exposure. To evaluate our initial experience with the method, these patients were reviewed using medical records, operative notes, and radiological assessment to determine its indications and effectiveness. In each patient, using a limited further dissection, at least one cerclage wire was passed through the greater sciatic notch, embracing the proximal extent of a posterior column fragment. It was then tightened above the anterior-inferior iliac spine, achieving reduction. In 11 cases reduction was obtained to within 1 mm, and joint congruence with < 3 mm of residual displacement was obtained in 13 hips. This reduction was maintained until union, except in one case, where it was lost postsurgery. Cerclage wires may be used to successfully effect an indirect reduction of the posterior column from an anterior approach in fractures affecting both columns, where the posterior column fracture line is proximal. The technique may contribute to fracture stabilization, but supplementary fixation was added in 12 of our patients.

The influence of gonadotropic hormones on the EGF receptor regulation in the rat ovary.

Ovaries of immature rats are endowed with only a small number of EGF binding sites (59.2 X 10(-15) mol/mg protein). During development from day 20 to 28, the binding capacity increases 2.5 times, while the growth of the ovaries remains small. Treatment with FSH on day 20 advances the EGF binding capacity with a 4-fold increase in the number of binding sites within the first two days. HCG has no or only a slight effect on the EGF binding capacity. The EGF receptor formation after FSH treatment takes place before the ovaries begin to grow rapidly. Accelerated ovarian growth is associated with a decrease of EGF binding capacity reaching values below those of the control animals during the subsequent days. The dissociation constants (KD) of the FSH stimulated receptors and of receptors present during development are found in the order of 2.7 and 8.7 X 10(-9) M. The physiological function of the EGF receptor for ovarian cell proliferation and follicular growth is discussed.