Wireless, Skin-Interfaced Devices for Pediatric Critical Care: Application to Continuous, Noninvasive Blood Pressure Monitoring

Indwelling arterial lines, the clinical gold standard for continuous blood pressure (BP) monitoring in the pediatric intensive care unit (PICU), have significant drawbacks due to their invasive nature, ischemic risk, and impediment to natural body movement. A noninvasive, wireless, and accurate alternative would greatly improve the quality of patient care. Recently introduced classes of wireless, skin-interfaced devices offer capabilities in continuous, precise monitoring of physiologic waveforms and vital signs in pediatric and neonatal patients, but have not yet been employed for continuous tracking of systolic and diastolic BP-critical for guiding clinical decision-making in the PICU. The results presented here focus on materials and mechanics that optimize the system-level properties of these devices to enhance their reliable use in this context, achieving full compatibility with the range of body sizes, skin types, and sterilization schemes typically encountered in the PICU. Systematic analysis of the data from these devices on 23 pediatric patients, yields derived, noninvasive BP values that can be quantitatively validated against direct recordings from arterial lines. The results from this diverse cohort, including those under pharmacological protocols, suggest that wireless, skin-interfaced devices can, in certain circumstances of practical utility, accurately and continuously monitor BP in the PICU patient population.

Skin-interfaced soft microfluidic systems with modular and reusable electronics for in situ capacitive sensing of sweat loss, rate and conductivity

Important insights into human health can be obtained through the non-invasive collection and detailed analysis of sweat, a biofluid that contains a wide range of essential biomarkers. Skin-interfaced microfluidic platforms, characterized by soft materials and thin geometries, offer a collection of capabilities for in situ capture, storage, and analysis of sweat and its constituents. In ambulatory uses cases, the ability to provide real-time feedback on sweat loss, rate and content, without visual inspection of the device, can be important. This paper introduces a low-profile skin-interfaced system that couples disposable microfluidic sampling devices with reusable 'stick-on' electrodes and wireless readout electronics that remain isolated from the sweat. An ultra-thin capping layer on the microfluidic platform permits high-sensitivity, contactless capacitive measurements of both sweat loss and sweat conductivity. This architecture avoids the potential for corrosion of the sensing components and eliminates the need for cleaning/sterilizing the electronics, thereby resulting in a cost-effective platform that is simple to use. Optimized electrode designs follow from a combination of extensive benchtop testing, analytical calculations and FEA simulations for two sensing configurations: (1) sweat rate and loss, and (2) sweat conductivity, which contains information about electrolyte content. Both configurations couple to a flexible, wireless electronics platform that digitizes and transmits information to Bluetooth-enabled devices. On-body field testing during physical exercise validates the performance of the system in scenarios of practical relevance to human health and performance.

Skin-interfaced biosensors for advanced wireless physiological monitoring in neonatal and pediatric intensive-care units

Standard of care management in neonatal and pediatric intensive care units (NICUs and PICUs) involve continuous monitoring of vital signs with hard-wired devices that adhere to the skin and, in certain instances, include catheter-loaded pressure sensors that insert into the arteries. These protocols involve risks for complications and impediments to clinical care and skin-to-skin contact between parent and child. Here we present a wireless, non-invasive technology that not only offers measurement equivalency to these management standards but also supports a range of important additional features (without limitations or shortcomings of existing approaches), supported by data from pilot clinical studies in the neonatal intensive care unit (NICU) and pediatric ICU (PICU). The combined capabilities of these platforms extend beyond clinical quality measurements of vital signs (heart rate, respiration rate, temperature and blood oxygenation) to include novel modalities for (1) tracking movements and changes in body orientation, (2) quantifying the physiological benefits of skin-to-skin care (e.g. Kangaroo care) for neonates, (3) capturing acoustic signatures of cardiac activity by directly measuring mechanical vibrations generated through the skin on the chest, (4) recording vocal biomarkers associated with tonality and temporal characteristics of crying impervious to confounding ambient noise, and (5) monitoring a reliable surrogate for systolic blood pressure. The results have potential to significantly enhance the quality of neonatal and pediatric critical care.

Neutral metallated and meso-substituted porphyrins as antimicrobial agents against gram-positive pathogens

Staphylococcus aureus is a bacterial pathogen that causes severe infections among humans. The increasing emergence of antibiotic resistance necessitates the development of new strategies to combat the spread of disease. One approach is photodynamic inactivation using porphyrin photosensitizers, which generate superoxide and other radicals in the presence of light, causing cell death via the oxidation of proteins and lipids. In this study, we analyzed a novel library of meso-substituted and metallated porphyrins for activity against multidrug-resistant S. aureus. From a library of 251 compounds, 51 showed antimicrobial activity, in three discrete classes of activity: those that functioned only in light, those that had toxicity only in darkness, and those that displayed activity regardless of illumination. We further demonstrated the broad-spectrum activity of these compounds against a variety of pathogens, including Bacillus anthracis, Enterococcus faecalis, and Escherichia coli. Minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) analyses of lead compounds (XPZ-263 and XPZ-271) revealed strong activity and killing towards methicillin-resistant S. aureus (MRSA) strains. An analysis of mutation frequencies revealed low incidences of resistance to lead compounds by E. coli and MRSA. Finally, an exploration of the underlying mechanism of action suggests that these compounds do not depend solely upon light-induced radical generation for toxicity, highlighting their potential for clinical applications.

Should a history section be included on the National Youth Sports Program preparticipation physical examination?

The National Youth Sports Program (NYSP) is an annual event sponsored by the National Collegiate Athletic Association that provides structured sports and enrichment programs to youth of low socioeconomic status. As part of the program, youths undergo a free medical examination that uses a physical examination checklist but does not include a section on medical history. To determine what additional information a medical history would provide, a history form was used in conjunction with the regular preparticipation examination for participants in the 1996 NYSP at the North Carolina Agricultural and Technical State University. The history form provided information such as family history of sudden death, personal history of asthma or bone injury, and whether participants took medications or used corrective lenses. Seventy-nine percent of the completed history forms documented a positive response to at least one question. Of these, only 5% had physical findings on examination. Conversely, 15% of participants had physical findings that were not reported on the history form. Because much of what is discovered by a medical history often is not found on physical examination and because history information can be used to prevent the occurrence of an accident or illness, this study suggests that the use of such a form is beneficial in providing a more comprehensive screening.

Lisfranc injury of the foot: a commonly missed diagnosis

Lisfranc joint injuries are rare, complex and often misdiagnosed. Typical signs and symptoms include pain, swelling and the inability to bear weight. Clinically, these injuries vary from mild sprains to fracture-dislocations. On physical examination, swelling is found primarily over the midfoot region. Pain is elicited with palpation along the tarsometatarsal articulations, and force applied to this area may elicit medial or lateral pain. Radiographs showing diastasis of the normal architecture confirm the presence of a severe sprain and possible dislocation. Negative standard and weight-bearing radiographs do not rule out a mild (grade I) or moderate (grade II) sprain. Reevaluation may be necessary if pain and swelling continue for 10 days after the injury. Proper treatment of a mild to moderate Lisfranc injury improves the chance of successful healing and reduces the likelihood of complications. Patients with fractures and fracture-dislocations should be referred for surgical management.

The association between flexibility and running economy in sub-elite male distance runners

The purpose of this study was to examine the association between nine measures of limb and trunk flexibility and running economy. Within a week prior to running economy assessment, and after 10 min of jogging at 3.13 m.s-1, 19 well-trained male sub-elite distance runners underwent two complete sets of lower limb and trunk flexibility assessments. Runners then completed two 10-min running economy assessment sessions on consecutive days at 4.13 m.s-1 following two 30-min sessions of treadmill accommodation at 4.13 m.s-1. Intraclass correlation coefficients indicated that the repeated flexibility measurements were highly reliable (X R = 0.92 +/- 0.09), as were the two running economy appraisals (R = 0.99). Correlational analyses revealed that dorsiflexion (r = 0.65) and standing hip rotation (r = 0.53) were significantly (P < or = 0.05) associated with the mean aerobic demand of running, such that runners who were less flexible on these measures were more economical. Although speculative, these results suggest that inflexibility in certain areas of the musculoskeletal system may enhance running economy in sub-elite male runners by increasing storage and return of elastic energy and minimizing the need for muscle-stabilizing activity.

Clearing athletes for participation in sports. The North Carolina Medical Society Sports Medicine Committee's recommended examination

The North Carolina Medical Society's Medicine Committee has reviewed current U.S. literature on preparticipation examinations and adopted a documentation form that fits the specific needs of our state. In spite of a recently published comprehensive monograph on preparticipation physical evaluation, no national consensus exists about whether comprehensive preparticipation exams or brief, focused examinations are better. With this in mind, we limited medical history questions to those determined by previous studies to identify specific problems. Also included are evaluations of blood pressure, musculoskeletal, and cardiovascular systems since studies have shown significant yield from these. The same studies find little benefit from the remainder of a comprehensive physical assessment. The recommended evaluation represents a minimal standard and addresses the core areas likely to prevent athletes from participating safely in sports. No recommended exam could cover all issues that affect school-age athletes--health prevention, adolescent development, general medical care, and psychological stresses--but physicians can use the recording form as a starting point and incorporate a more extensive evaluation into the assessment of athletes found to be at increased risk. Consistent use of this examination should promote better detection of sport-specific risks related to cardiovascular disorders, asthma, musculoskeletal problems, concussions, heat-related problems, and general medical problems. The Sports Medicine Committee wants to promote physical activity. Before disqualifying athletes physicians should remember that the disqualification rate in published studies averages only 1%. When questions about the need for disqualification arise, consultation may be advisable.(ABSTRACT TRUNCATED AT 250 WORDS)

Rehabilitation exercises for common sports injuries

Residual weakness after joint injury is a risk factor for recurrent injury. A rehabilitation program helps patients recover strength and helps prevent further injuries. Orthopedic injuries account for 10 percent of visits to family physicians, yet many primary care physicians do not routinely prescribe rehabilitation exercises for injured patients. Illustrations of exercises for the hip, knee, ankle and shoulder are included as a reference for family physicians to use when prescribing rehabilitation exercises.

Leiomyosarcoma of the femoral vein in a marathon runner

Leiomyosarcoma of the femoral vein is a rare tumor. Physicians involved in the care of athletic patients must not be cavalier in evaluating overuse injuries and should endeavor to make a specific diagnosis. If atypical findings, such as generalized extremity swelling, are present, the physician must consider systemic illness including malignancy in apparently healthy, physically active individuals.

Head Injuries in Soccer

In brief: Although soccer is considered a safe sport, fatal head injuries have occurred on rare occasion. Mechanisms of injury include heading the ball improperly and making head-to-head contact; injury may also occur when a forcefully kicked ball strikes a player's head. Goalkeepers most commonly sustain collision injuries when the head strikes the goalpost, the playing field, or another player's elbow, foot, or head. The author reviews the medical literature on soccer injuries and contends that rule changes and other measures may be more appropriate than the use of helmets to prevent head injuries.