Brachial blood pressure-independent relations between radial late systolic shoulder-derived aortic pressures and target organ changes

Central aortic blood pressure (BP; BPc) predicts outcomes beyond brachial BP. In this regard, the application of a generalized transfer function (GTF) to radial pulse waves for the derivation of BPc is an easy and reproducible measurement technique. However, the use of the GTF may not be appropriate in all circumstances. Although the peak of the second shoulder of the radial waveform (P2) is closely associated with BPc, and, hence, BPc may be assessed without the need for a GTF, whether P2-derived BPc is associated with adverse cardiovascular changes independent of brachial BP is uncertain. Thus, P2- and GTF-derived aortic BPs were assessed using applanation tonometry and SphygmoCor software. Left ventricular mass was indexed for height(1.7) (n=678) and carotid intima-media thickness (IMT; n=462) was determined using echocardiography and vascular ultrasound. With adjustments for nurse-derived brachial pulse pressure (PP), P2-derived central PP was independently associated with left ventricular mass indexed for height(1.7) (partial r=0.18; P<0.0001) and IMT (partial r=0.40; P<0.0001). These relations were similar to nurse-derived brachial PP-independent relations between GTF-derived central PP and target organ changes (left ventricular mass indexed for height(1.7): partial r=0.17, P<0.0001; IMT: partial r=0.37, P<0.0001). In contrast, with adjustments for central PP, nurse-derived brachial PP-target organ relations were eliminated (partial r=-0.21 to 0.05). Twenty-four-hour, day, and night PP-target organ relations did not survive adjustments for nurse-derived brachial BP. In conclusion, central PP derived from P2, which does not require a GTF, is associated with cardiovascular target organ changes independent of brachial BP. Thus, when assessing adverse cardiovascular effects of aortic BP independent of brachial BP, P2-derived measures may complement GTF-derived measures of aortic BP.     

Residual neuromuscular block as a risk factor for critical respiratory events in the post anesthesia care unit

ObjectiveResidual neuromuscular block is an important postoperative complication associated to the use of neuromuscular blocking drugs. The purpose of this study was to access the incidence of residual neuromuscular block in a post-anesthesia care unit and to evaluate its association with critical respiratory events.Material and methodsProspective cohort study was conducted in a Post Anesthetic Care Unit (PACU) for a period of 3 weeks. Two hundred two adult patients who submitted to scheduled non-cardiac and non-intracranial surgery were eligible to the study. The primary outcome variable was residual neuromuscular block after arrival to PACU that was defined as train-of-four ratio <0.9 and objectively quantified using acceleromyography. Demographic data, perioperative variables, lengths of hospital and recovery room stay and critical respiratory events were recorded. Inadequate emergence was classified in its different forms according to the Richmond agitation and sedation scale 10 min after admission to the recovery room.ResultsResidual neuromuscular block incidence in the post-anesthesia care unit was 29.7% (95% confidence interval: 23.4, 36.1). Patients with residual neuromuscular block had more frequently overall critical respiratory events (51% versus 16%, P < 0.001), airway obstruction (10% versus 2%, P = 0.029), mild-moderate hypoxemia (23% versus 4%, P < 0.001), severe hypoxemia (7% versus 1%, P = 0.033), respiratory failure (8% versus 1%, P = 0.031), inability to breathe deeply (38% versus 12%, P < 0.001) and muscular weakness (16% versus 1%, P < 0.001). Residual neuromuscular block was more common after high-risk surgery (53% versus 33%, P = 0.011) and was more often associated with post-operative hypoactive emergence as defined by the Richmond Agitation and Sedation Scale (21% versus 6%, P = 0.001).ConclusionsThis study suggests that residual neuromuscular block is common in the PACU and is associated with more frequent critical respiratory events.     

The use of Permacol for the reconstruction of a complex thoraco-abdominal wall defect from a recurrent leiomyosarcoma

Complex thoraco-abdominal wall defects following tumor resection create a unique reconstructive challenge, which centers on anatomically re-establishing the thoracic and abdominal compartments to prevent visceral herniation. Autologous tissue may not be available or adequate to reconstruct these defects; therefore, the use of alternative options, such as non-autologous material, is often necessary. To our knowledge, very little has been described about the use of biologic mesh for the reconstruction of large thoracic defects. We present a review of the literature and present a novel approach to address a difficult defect with the use of cross-linked porcine dermal collagen (Permacol) to bridge a thoraco-abdominal defect while stabilizing the diaphragm. Level of Evidence: Level V, therapeutic study.     

Diffusion tensor imaging in brainstem tuberculoma

Integrity of descending white matter tracts can be evaluated by diffusion tensor imaging. In rim-enhancing intraparenchymal lesions, this technique can assist in the differentiation of demyelinating disease from tumor or abscess. Diffusion tensor imaging characteristics of tuberculoma have not been previously reported to our knowledge. A patient with headaches, dizziness, and mild left-sided weakness underwent MRI with diffusion tensor imaging. A large, rim-enhancing lesion within the pons was discovered, which subsequently was diagnosed as tuberculoma. Tractography maps prepared from diffusion tensor imaging data revealed predominantly displaced descending fiber tracts in the region of the rim-enhancing lesion. A few tracts adjacent to the lesion appeared truncated, and this abnormal finding correlated to the patient’s clinical deficit. The tractography characteristics of diffusion tensor imaging in this patient potentially are distinct from those seen with demyelinating lesions, which may show more extensive tract truncation. Together with the consonance of exam findings and tract truncation seen in this patient, tractography may prove useful in the diagnosis of suspected tuberculoma.     

Physiologically based controller for generating overground locomotion using functional electrical stimulation

The physiological control of stepping is governed both by signals descending from supraspinal systems and by circuitry residing within the lumbosacral spinal cord. The goal of this study was to evaluate the capacity of physiologically based controllers to restore functional overground locomotion after neurological damage, such as spinal cord injury when used in conjunction with functional electrical stimulation. For this purpose we implemented and tested two controllers: 1) an intrinsically timed system that generated a predetermined rhythmic output and 2) a sensory-based system that used feedback signals to make appropriate transitions between the unloaded (flexion) and loaded (extension) phases of the gait cycle. A third controller, a combination of the intrinsically timed and sensory-driven controllers, was implemented and two sessions were conducted to demonstrate the functional advantages of this approach. The controllers were tested in anesthetized cats, implanted with intramuscular electrodes in six major extensor and flexor muscles of the hindlimbs. The cats were partially supported on a sliding trolley that was propelled by the hindlimbs along a 2.5-m instrumented walkway. Ground reaction forces and limb positions were measured by force plates in the walkway and by accelerometers secured to the legs of the cat, respectively. The controllers were used to generate patterns of stimulation that would elicit alternating flexor (swing) and extensor (stance) movements in the hindlimbs. Using either the intrinsically timed or sensory-driven controllers, the cats were able to travel a distance of 2.5 m, taking five to 12 steps. Functional stepping sequences were more easily achieved using the intrinsically timed controller as the result of a lower sensitivity to the selection of initial stimulation parameters. However, unlike the sensory-driven controller, the intrinsically timed controller was unable to adjust to overcome walkway resistance and muscle fatigue. Neither system was consistently able to ensure load-bearing stepping. Therefore we propose the use of a "combined controller" that relies heavily on intrinsic timing but that can be reset based on sensory signals. A combined controller such as this one may provide the best solution for restoring robust overground locomotion after spinal cord injury.     

The placement of osseointegrated dental implants in a patient with type IV B osteogenesis imperfecta: a 9-year follow-up

Osteogenesis imperfecta (OI) is a rare autosomal dominant connective tissue and metabolic disorder. Typically, patients with OI exhibit bone fragility, with the sclera, joints, skin, and tooth dentin being affected to varying degrees. Despite existing classifications, there is an extreme phenotypic variation within this population, and at times the mild forms of OI may be difficult to diagnose. Comprehensive management of the severe types of OI involves aggressive physical and surgical orthopaedic treatment to improve muscle structure and joint mobility. For those patients with associated dentinogenesis imperfecta (DI), early and definitive management can help prevent excessive tooth wear and sensitivity. A case of a late diagnosis of type IV OI with DI successfully treated with implant-supported dentures is reported. To date, 9 years after implant surgery and prosthetic loading, the patient continues to be clinically and radiographically normal.