The effect of delirium preventive measures on the occurrence of postoperative cognitive dysfunction in older adults undergoing cardiovascular surgery. The DelPOCD randomised controlled trial.

STUDY OBJECTIVE: This trial examines the effect of delirium preventive measures on the incidence of postoperative cognitive dysfunction in older adults. DESIGN: In a randomised approach, a delirium prevention and a standard care group were compared regarding manifestation of postoperative cognitive dysfunction at seven days, three and twelve months postoperatively (primary outcome). To correct for practice effects and age-depended cognitive decline, a control group of age-matched healthy subjects was included. SETTING: The trial was conducted at the University Medical Centre Hamburg between 2014 and 2018, data assessment took place in the Anaesthesia Outpatient Clinic and on the surgical ward. PATIENTS: A total of 609 patients ≥60 years scheduled for cardiovascular surgery were enrolled, allocated treatment was received by 284 patients in the delirium prevention and 274 patients in the standard care group. INTERVENTION: The intervention consisted of a delirium prevention bundle including reorientation measures, sleeping aids and early mobilisation. MEASUREMENTS: Cognitive functions were assessed via neuropsychological testing of attention, executive functions including word fluency, and verbal memory utilizing a computerised test of attentional performance, the trail making test, the digit span subtest from the Wechsler Adult Intelligence Scale-IV, the verbal learning and memory test, and the Regensburg Word Fluency Test. Assessments were performed preoperatively and at three time points postoperatively (one week, three months and 12 months). MAIN RESULTS: Postoperative cognitive dysfunction was defined as a clinically meaningful decline in at least two out of nine chosen test parameters compared to the preoperative level (reliable change index ≤ - 1.96). The rates of postoperative cognitive dysfunction were 25.9% (delirium prevention group, n = 284) vs. 28.1% (standard care group, n = 274) [X2(1,n = 433) = 0.245;p = 0.621] at postoperative day seven and declined to 7.8% vs. 6.8% [X2(1,n = 219) = 0.081;p = 0.775] and 1.3% vs. 5.6% (p = 0.215, Fisher's exact test) at three and 12 months following surgery, respectively. The postoperative delirium rates did not differ between the two groups (delirium prevention group: 13.4% vs. standard care group: 17.3%). Attentional performance was impaired shortly after surgery, whereas verbal delayed recall was most frequently affected over the whole postoperative period. CONCLUSION: These findings suggest that an intervention combining specific measures extracted from established postoperative delirium prevention programs did not reduce the rate of postoperative cognitive dysfunction in older adults.

Mechanotransduction in the lungs.

Mechanical ventilation may induce or aggravate lung injury, a phenomenon known as ventilator induced lung injury (VILI). On a macroscopic level, the effects of mechanical stress and strain on lung tissue are well described. Increased tidal volumes may lead to volutrauma, raised airway pressures may cause barotrauma and cyclic collapse and reopening of alveolar units contributes to atelectrauma. These three harmful mechanisms may lead to local and systemic pulmonary inflammatory response known as biotrauma. The purpose of this review was to elucidate fundamental mechanisms involved in the mechanotransduction of mechanical stimuli on a cellular level. Bronchial epithelial cells in the distal airways as well as alveolar epithelial cells are exposed to a variety of mechanical forces. These cells are involved in sensing and translation of mechanical stimuli into an inflammatory response. This review provides insight into current knowledge of cellular and molecular pathways during the process of pulmonary epithelial mechanosensation and mechanotransduction under different mechanical conditions. Since evidence for specific pathways is generally lacking in some fields of alveolar epithelial mechanotransduction, this article aims at providing reasonable hypothesis for further investigation.

[Transfusion-related acute lung injury]. / Transfusionsassoziierte akute Lungeninsuffizienz.

Transfusion-related acute lung injury (TRALI) developed into the leading cause of transfusion-related morbidity and mortality after the first description by Popovsky et al. approximately three decades ago. It was the most frequent reason for transfusion-related fatalities worldwide before implementation of risk minimization strategies by donor selection. Plasma-rich blood products, such as fresh frozen plasma and apheresis platelets seem to be the leading triggers of TRALI. Hypoxemia and development of pulmonary edema within 6 h of transfusion are the diagnostic criteria for TRALI. The differentiation between cardiac failure and other transfusion-related lung injuries, such astransfusion-associated circulatory overload ( TACO) is difficult and causal treatment is not available. Therapy is based on supportive measures, such as oxygen insufflationor mechanical ventilation. The exactly pathogenesis is still unknown but the most propagated hypothesis is the two-event-model. Neutrophils are primed by the underlying condition, e.g. sepsis or trauma during the first event and these primed neutrophils are activated by transfused leukoagglutinating antibodies (immunogen) or bioreactive mediators (non-immunogen) during the second-event. Transfusion of leukoagglutinating antibodies from female donors with one or more previous pregnancies is the most frequent reason. No more TRALI fatalities were reported after implementation of the donor selection in Germany in 2009.

[When the resting membrane potential becomes restless. Acute hyperkalemia in the perioperative phase]. / Wenn das Ruhemembranpotenzial aus der Ruhe kommt. Akute Hyperkaliämie in der perioperativen Phase.

Acute hyperkalemia is a life-threatening event and often occurs abruptly and without warning in the perioperative field. Risk factors are found on multiple levels as they can derive from a patients pre-existing condition or result from the surgical intervention or management of anesthesia. The therapy of hyperkalemia depends on the dimensions of electrolyte disturbance and a distinction can be made between therapeutic measures with a rapid and those with a long-term effect.

[Hemodynamic monitoring in one-lung ventilation]. / Hämodynamisches Monitoring bei Einlungenventilation.

One-lung ventilation causes adverse effects in pulmonary gas exchange and cardiocirculatory function. These adverse effects become particularly important for patients with underlying cardiopulmonary comorbidities. Alterations in pulmonary gas exchange have been investigated in several experimental and clinical trials. However, the hemodynamic consequences of one-lung ventilation are to a great extent unknown. Furthermore, no conclusive recommendations exist as to which kind of hemodynamic monitoring should be preferred in the situation of one-lung ventilation. Many issues regarding hemodynamic monitoring in one-lung ventilation remain unacknowledged. This article will review the current literature on hemodynamic monitoring in one-lung ventilation in order to derive recommendations for the application of hemodynamic monitoring in this specific peri-operative situation.

Leukocyte sequestration in pulmonary microvessels and lung injury following systemic complement activation in rabbits.

Inflammatory reactions are associated with sequestration of leukocytes in the lung. Complement activation leads to accumulation of leukocytes in alveolar septa and alveoli, to lung edema and hemorrhage. Although in organs other than the lung leukocytes interact with the vascular endothelium only in postcapillary venules, alveolar capillaries are considered to be the site of leukocyte sequestration in the lung. However, pulmonary venules and arterioles have not been investigated systematically after complement activation so far. A closed thoracic window was implanted in anesthetized rabbits; leukocytes and red blood cells were stained, and the movement of these cells was measured in superficial pulmonary arterioles, venules and alveolar capillaries using fluorescence video microscopy before and 30 and 60 min after infusion of cobra venom factor (CVF). Erythrocyte velocity and macrohemodynamic conditions did not change after CVF infusion and were not different from the sham-treated controls. The number of sticking leukocytes increased significantly compared to baseline and control: by 150% in arterioles and in venules and by 740% in alveolar capillaries within 60 min after CVF infusion. The width of alveolar septa in vivo was significantly enlarged after CVF infusion, indicating interstitial pulmonary edema. At the end of the experiments, myeloperoxidase activity was higher in the CVF group, showing leukocyte sequestration in the whole organ. It is concluded that complement activation by CVF induces leukocyte sequestration in lung arterioles, venules and alveolar capillaries and leads to mild lung injury.

Intraoperative detection of malignant gliomas by 5-aminolevulinic acid-induced porphyrin fluorescence.

OBJECTIVE: Survival after surgery and radiotherapy for the treatment of malignant gliomas is linked to the completeness of tumor removal. Therefore, methods that permit intraoperative identification of residual tumor tissue may be of benefit. In a preliminary investigation, we have studied the value of fluorescent porphyrins that accumulate in malignant tissue after administration of a precursor (5-aminolevulinic acid) for labeling of malignant gliomas in nine patients. METHODS: Three hours before the induction of anesthesia, 10 mg 5-aminolevulinic acid/kg body weight was administered orally. Intraoperatively, red porphyrin fluorescence was observed with a 455-nm long-pass filter after excitation with violet-blue (375-440 nm) xenon light and was verified by analysis of fluorescence spectra. Fluorescing and nonfluorescing samples taken from the tumor perimeters were examined histologically or used to study the photobleaching of porphyrins by excitation light and white light from the operating microscope. Plasma and erythrocyte porphyrin levels were determined by fluorescence photometry. RESULTS: Normal brain tissue revealed no porphyrin fluorescence, whereas tumor tissue was distinguished by bright red fluorescence. For a total of 89 tissue biopsies, sensitivity was 85% and specificity was 100% for the detection of malignant tissue. For seven of nine patients, visible porphyrin fluorescence led to further resection of the tumor. Under operating light conditions, fluorescence decayed to 36% in 25 minutes for violet-blue light and in 87 minutes for white light. Plasma and erythrocyte porphyrin contents increased slightly, without exceeding normal levels. CONCLUSION: Our observations suggest that 5-aminolevulinic acid-induced porphyrin fluorescence may label malignant gliomas safely and accurately enough to enhance the completeness of tumor removal.

Excessive arterial thrombus in spherocytosis. A case report.

Spherocytosis is the most common of the hereditary hemolytic anemias, with characteristically shaped erythrocytes. An unusually large amount of arterial thrombus was documented in a dissected artery after angioplasty in a patient with spherocytosis. It is hypothesized that the excessive arterial thrombus may have been linked to the spherocytosis.