Research Spotlight

Wiederkehr, M.R., Benevides, R., Jr., Santa Ana, C.A. and Emmett, M. (2021). “Pseudohyperchloremia and Negative Anion Gap – Think Salicylate!” Am J Med.

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BACKGROUND: Pseudohyperchloremia results in a very low or negative anion gap (AG). Historically, the most common cause of this artifact was bromide poisoning. Bromide salts have been removed from most medications and bromism has become very uncommon. More recently, the introduction of chloride ion selective sensing electrodes (Cl-ISE) has generated a new cause of pseudohyperchloremia – salicylate poisoning. We describe five such patients and quantitate the error generated by this measurement artifact. METHODS: The magnitude of artifactual hyperchloremia generated by high salicylate levels was quantified in five patients by measuring [Cl] with several Cl-ISEs from different manufacturers and with Cl-ISEs of different “ages” and comparing these results to measurements with a chloridometer (coulometric titration) which is free of the salicylate artifact. RESULTS: Cl-ISEs from different manufactures generated a wide range of artifactual [Cl] elevation. Furthermore, the same Cl-ISE generated increasingly severe pseudohyperchloremia as it was repeatedly reused over time and “aged”. CONCLUSIONS: Salicylate interferes with measurement of the blood [Cl] when a Cl-ISE is used. The severity of this artifact is related to the salicylate level, the specific Cl-ISE, and the “age” of the electrode. Toxic blood salicylate levels can generate marked pseudohyperchloremia, and consequently an artifactual very small or negative [AG]. The large anion gap metabolic acidosis typical of salicylate poisoning is masked by this artifact. Salicylate has become the most common cause of pseudohyperchloremia and physicians should immediately consider salicylate poisoning whenever the combination of hyperchloremia and a very small or negative anion gap is reported by the laboratory.

Edgerton, J.R. and Damiano, R.J., Jr. (2021). “Commentary: What is the measure of success for atrial fibrillation ablation? Is a reduction in arrhythmia burden sufficient?” J Thorac Cardiovasc Surg.

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In this issue of the Journal, Li and colleagues1 follow a small cohort of patients with paroxysmal atrial fibrillation (PAF) and previous cerebrovascular or peripheral thromboembolism, without previous intervention, who underwent stand-alone thoracoscopic pulmonary vein isolation and left atrial appendage excision. They compared these patients with a smaller group who opted for medical management. After controlling for CHA2DS2-VASc score (ie, congestive heart failure; hypertension; age ≥75 years; diabetes mellitus, stroke, or transient ischemic attack; vascular disease; age 65-74 years; sex category), the authors found that pulmonary vein isolation delayed progression of PAF. [No abstract; excerpt from Commentary].

Driver, S., Reynolds, M., Brown, K., Vingren, J.L., Hill, D.W., Bennett, M., Gilliland, T., McShan, E., Callender, L., Reynolds, E., Borunda, N., Mosolf, J., Cates, C. and Jones, A. (2021). “Effects of wearing a cloth face mask on performance, physiological and perceptual responses during a graded treadmill running exercise test.” Br J Sports Med.

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OBJECTIVES: To (1) determine if wearing a cloth face mask significantly affected exercise performance and associated physiological responses, and (2) describe perceptual measures of effort and participants’ experiences while wearing a face mask during a maximal treadmill test. METHODS: Randomised controlled trial of healthy adults aged 18-29 years. Participants completed two (with and without a cloth face mask) maximal cardiopulmonary exercise tests (CPETs) on a treadmill following the Bruce protocol. Blood pressure, heart rate, oxygen saturation, exertion and shortness of breath were measured. Descriptive data and physical activity history were collected pretrial; perceptions of wearing face masks and experiential data were gathered immediately following the masked trial. RESULTS: The final sample included 31 adults (age=23.2±3.1 years; 14 women/17 men). Data indicated that wearing a cloth face mask led to a significant reduction in exercise time (-01:39±01:19 min/sec, p<0.001), maximal oxygen consumption (VO(2)max) (-818±552 mL/min, p<0.001), minute ventilation (-45.2±20.3 L/min), maximal heart rate (-8.4±17.0 beats per minute, p<0.01) and increased dyspnoea (1.7±2.9, p<0.001). Our data also suggest that differences in SpO(2) and rating of perceived exertion existed between the different stages of the CPET as participant's exercise intensity increased. No significant differences were found between conditions after the 7-minute recovery period. CONCLUSION: Cloth face masks led to a 14% reduction in exercise time and 29% decrease in VO(2)max, attributed to perceived discomfort associated with mask-wearing. Compared with no mask, participants reported feeling increasingly short of breath and claustrophobic at higher exercise intensities while wearing a cloth face mask. Coaches, trainers and athletes should consider modifying the frequency, intensity, time and type of exercise when wearing a cloth face mask.

Beebe, K.E., Reynolds, E. and Driver, S. (2021). “One size fits none: neurobiologic-specific modifications for the assessment, diagnosis, and treatment of sport-related concussion (SRC).” Brain Inj 35(5): 505-510.

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PRIMARY OBJECTIVE: – To discuss how the underlying neuroanatomy and neurobiology of five sport-related concussion (SRC) clinical profiles impacts assessment and treatment. RESEARCH DESIGN: – Narrative review. METHODS AND PROCEDURES: – Based on the current literature and clinical experience, arguments against the traditional SRC protocol and for a clinical profiles-based SRC protocol are made. MAIN OUTCOMES AND RESULTS: – While the clinical profiles-based SRC protocol is widely used and accepted, there has been little published regarding the link to the underlying neuropathology. Our narrative review describes the five SRC clinical profiles: vestibular, ocular, mood, post-traumatic migraine, and cognitive/fatigue. For these profiles, the underlying neuroanatomy and neurobiology is outlined, as well as how that anatomy and biology impact the profiles’ etiology, assessment, and treatment. The cervical and sleep modifiers are also briefly covered. CONCLUSIONS: – Utilizing this model, clinicians are able to provide an individualized assessment, conceptualization, and treatment plan for SRC, leading to improved outcomes and clinical experiences for athletes.

Shih, E., Squiers, J.J. and DiMaio, J.M. (2021). “Systematic Review of Minimally Invasive Surgery for Mitral Valve Infective Endocarditis.” Innovations (Phila): 1556984521997086.

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OBJECTIVE: The scope of application of minimally invasive mitral valve surgery is expanding. However, the safety and efficacy of minimally invasive mitral valve surgery in the setting of infective endocarditis is not well known. We sought to identify the best evidence available to support a minimally invasive surgical approach for mitral valve infective endocarditis. METHODS: A systematic review of minimally invasive mitral valve surgery for infective endocarditis was conducted according to the Preferred Reporting Items for Systematic reviews and Meta-Analyses (PRISMA) guidelines. RESULTS: A total of 6 manuscripts describing 271 patients were identified. Mean age was 60.4 ± 14.9 years old, and 60.1% patients were male. Mean EuroSCORE II was 24.6 ± 23.2. Mitral valve repair was achieved in 32.4% of cases. The average in-hospital mortality was 9.4%, and average length of hospital stay was 21.6 days. Survival was 89.1% at 30 days, and 1-year survival was 79.3%. Rate of conversion to sternotomy was 1.8%. Postoperative complications included: 6.9% postoperative bleeding, 9.3% new postoperative dialysis, 2.3% postoperative stroke, and 3.4% recurrence of endocarditis. Reoperation over the long-term was required in 9.3% of cases. CONCLUSIONS: Minimally invasive mitral valve surgery for infective endocarditis has acceptable perioperative morbidity as well as short- and intermediate-term mortality at experienced centers. Minimally invasive mitral valve surgery may be an acceptable alternative approach to infective endocarditis and warrants further study.