Monitoring activated clotting time for combined heparin and aprotinin application: an in vitro evaluation of a new aprotinin-insensitive test using SONOCLOT

The kaolin-based activated clotting time (ACT) is commonly used for monitoring heparin-induced anticoagulation alone and combined with aprotinin during cardiopulmonary bypass. However, aprotinin prolongs ACT measurements. Recently, a new so-called 'aprotinin-insensitive' ACT test (SaiACT) has been developed for the SONOCLOT analyzer. In this study we evaluated and compared this new test for the SONOCLOT analyzer in vitro with an established kaolin-based ACT from HEMOCHRON (HkACT). Twenty-five patients undergoing elective valve surgery donated 80 mL of blood after induction of anesthesia. The blood was withdrawn in citrated tubes and processed to analyze effects of heparin (0, 1, 2, and 3 U x mL(-1)), aprotinin (0, 200 kIU x mL(-1)), and 25% hemodilution with calcium-free lactated Ringer's solution on ACT measurements. A total of 400 blood samples were analyzed and ACT was measured in a wide, clinically relevant range in duplicate with SaiACT and HkACT. Addition of aprotinin to heparinized blood samples induced no significant changes of SaiACT measurements. By contrast, HkACT readings increased significantly: aprotinin prolonged HkACT in heparinized blood samples by 20% +/- 37% (2 U x mL(-1)) and 24% +/- 18% (3 U x mL(-1)), respectively, and in vitro hemodilution increased this effect. IMPLICATIONS: Current standard techniques to measure heparin-induced anticoagulation during cardiopulmonary bypass are affected by aprotinin, a drug widely used in this setting. The aim of this study was to investigate in vitro a new, so-called 'aprotinin-insensitive' test from SONOCLOT to measure heparin-induced anticoagulation more reliably in combination with aprotinin.     

Micturition Syncope due to paraprostatic pheochromocytoma

Paraprostatic pheochromocytoma is a very rare localization of extra-adrenal pheochromocytoma. The clinical and anatomical features of a 41-year-old man are described.     

The route of administration (oral vs intravenous) does not influence dose or outcome in Graves’ disease and unifocal autonomy

Purpose In a prospective randomised study, we investigated the influence of the route of administration of radioiodide on dosimetry and therapy outcome.Methods Fifty-four patients suffering from Graves disease (GD) and 60 patients with unifocal autonomy (UA) participated in the study and were randomly treated with either orally or intravenously administered radioiodide. Pretherapeutic dosimetry was based on single uptake measurements with a calibrated uptake probe system. The radioiodine kinetics during hospitalisation was assessed by daily bedside uptake measurements. Therapeutic dose was determined by half-life and thyroid uptake at the time of discharge using the same uptake probe as for the radioiodine test.Results No improvement in accuracy of dosimetry was achieved when radioiodide was administered intravenously. Mean therapeutic doses were identical following intravenous or oral administration. Variation in the achieved dose was slightly higher in the patients receiving oral administration, this being attributable to larger deviations in discrete activities of the capsules administered as compared with the values determined by dosimetry. No differences according to treatment modality were found with regard to therapeutic outcome. Eighty-seven patients attended 6-month follow-up after therapy. In the UA group, successful treatment, defined as a normal or elevated TSH level, was observed in 94% of patients after oral administration and in 80% after intravenous administration; corresponding figures in the GD group were 68% and 65%.Conclusion The causes of individual differences between targeted and therapeutically achieved doses remain undetermined. Variations in the bioavailability of radioiodide or other parameters affecting thyroid status may be involved, and further investigations are needed to clarify this.     

Role of biofilms in neurosurgical device-related infections

Bacterial biofilms have recently been shown to be important in neurosurgical device-related infections. Because the concept of biofilms is novel to most practitioners, it is important to understand that both traditional pharmaceutical therapies and host defense mechanisms that are aimed at treating or overcoming free-swimming bacteria are largely ineffective against the sessile bacteria in a biofilm. Bacterial biofilms are complex surface-attached structures that are composed of an extruded extracellular matrix in which the individual bacteria are embedded. Superimposed on this physical architecture is a complex system of intercellular signaling, termed quorum sensing. These complex organizational features endow biofilms with numerous microenvironments and a concomitant number of distinct bacterial phenotypes. Each of the bacterial phenotypes within the biofilm displays a unique gene expression pattern tied to nutrient availability and waste transport. Such diversity provides the biofilm as a whole with an enormous survival advantage when compared to the individual component bacterial cells. Thus, it is appropriate to view the biofilm as a multicellular organism, akin to metazoan eukaryotic life. Bacterial biofilms are much hardier than free floating or planktonic bacteria and are primarily responsible for device-related infections. Now that basic research has demonstrated that the vast majority of bacteria exist in biofilms, the paradigm of biofilm-associated chronic infections is spreading to the clinical world. Understanding how these biofilm infections affect patients with neurosurgical devices is a prerequisite to developing strategies for their treatment and prevention.     

Patterns of changes in arterial PO2 during one-lung ventilation: a comparison between patients with severe pulmonary emphysema and patients with preserved lung function

OBJECTIVES: One-lung ventilation (OLV) during thoracoscopic surgery is associated with a significant decline in arterial PO(2) in patients with severe pulmonary emphysema and patients with preserved lung function. The authors hypothesized that patterns of arterial PO(2) changes are different in these 2 patient groups. DESIGN: Prospective nonrandomized study. SETTING: University hospital. PARTICIPANTS: Twenty-five patients undergoing thoracoscopic interventions: 16 with severe pulmonary emphysema and 9 patients without emphysema. INTERVENTIONS: Continuous arterial blood gas measurement (PaO(2), PaCO(2), pHa) during OLV of the left lung in left lateral position using the Paratrend 7 blood gas monitoring system (PT7; Pfizer Hospital Products Group, High Wycombe, UK). MAIN RESULTS: The decrease of PaO(2) was delayed in patients with severe emphysema. Steady state (defined as DeltaPaO(2) <7.5 mmHg/min) was reached after 18 +/- 4 minutes compared with 11 +/- 3 minutes (mean +/- standard deviation) in patients with normal lung function (p = 0.0002). PaO(2) values at steady state were comparable (p = 0.49); the pattern of changes in PaO(2) for the first 15 minutes of left-sided OLV was significantly different between the groups (p = 0.0004). The difference of predicted versus measured PaO(2) at steady state was -48 +/- 160 mmHg for patients with emphysema and -51 +/- 60 mmHg for patients with normal lung function (p = 0.019). CONCLUSION: During OLV, oxygenation is better preserved for a longer period of time in patients with severe pulmonary emphysema as compared with patients with normal lung function. In contrast to patients without emphysema, prediction of oxygenation during OLV for the individual patient with emphysema is unreliable because of large interindividual differences.     

Grabbing your ear: rapid auditory-somatosensory multisensory interactions in low-level sensory cortices are not constrained by stimulus alignment

Multisensory interactions are observed in species from single-cell organisms to humans. Important early work was primarily carried out in the cat superior colliculus and a set of critical parameters for their occurrence were defined. Primary among these were temporal synchrony and spatial alignment of bisensory inputs. Here, we assessed whether spatial alignment was also a critical parameter for the temporally earliest multisensory interactions that are observed in lower-level sensory cortices of the human. While multisensory interactions in humans have been shown behaviorally for spatially disparate stimuli (e.g. the ventriloquist effect), it is not clear if such effects are due to early sensory level integration or later perceptual level processing. In the present study, we used psychophysical and electrophysiological indices to show that auditory-somatosensory interactions in humans occur via the same early sensory mechanism both when stimuli are in and out of spatial register. Subjects more rapidly detected multisensory than unisensory events. At just 50 ms post-stimulus, neural responses to the multisensory 'whole' were greater than the summed responses from the constituent unisensory 'parts'. For all spatial configurations, this effect followed from a modulation of the strength of brain responses, rather than the activation of regions specifically responsive to multisensory pairs. Using the local auto-regressive average source estimation, we localized the initial auditory-somatosensory interactions to auditory association areas contralateral to the side of somatosensory stimulation. Thus, multisensory interactions can occur across wide peripersonal spatial separations remarkably early in sensory processing and in cortical regions traditionally considered unisensory.     

Cardiac transplantation complicated by acute thrombotic occlusion of the right coronary artery

We report the case of a 63-year-old male patient undergoing cardiac transplantation due to fourth time aortic valve endocarditis. The postoperative course was complicated by thrombotic occlusion of the right coronary artery (RCA) causing acute right ventricular myocardial infarction, which required extracorporeal membrane oxygenation. The RCA could be reopened by catheter-based intervention and the patient stabilized. In order to avoid further immobilization, a right ventricular assist device was implanted and an aortocoronary bypass to the RCA was performed. After that, the patient stabilized progressively, could be weaned from the assist device, and was discharged home 6 weeks after transplantation. On coronary angiography, which is routinely performed 4 to 6 weeks after transplantation, a fistula from the RCA to the right ventricle was detected which was treated conservatively. Five months after transplantation, the patient is in good clinical condition without signs of recurrent endocarditis. This case shows that intense interdisciplinary cooperation of cardiac specialists allows the successful management of very complex patients in serious clinical conditions.