Aortic Pressure Estimation Using Blind Identification Approach on Single Input Multiple Output Nonlinear Wiener Systems.

Aortic pressure () is important for diagnosis of cardiovascular diseases, but it cannot be directly measured by noninvasive means. We present a method for its estimation by modeling arterial system as multichannel Weiner system with linear finite impulse response filter accounting for larger arteries transmission channel and nonlinear memoryless function block accounting for all nonlinearities due to narrowing of arteries, branching and visco-elastic forces. With this structure when pressure waveforms are measured from two distinct peripheral locations, multichannel blind system identification (MBSI) technique can be used to estimate common input pressure signal or . Nonlinear MBSI method was employed on previously acquired human hemodynamic measurements (seven datasets); results show can be accurately derived. This method by nature is self-calibrating to account for any interpersonal, along with intrapersonal, vascular dynamics inconstancy. Besides Pa estimation, the proposed MBSI method also allows extraction of system dynamics for vascular channels.

Validation of a novel nonlinear black box Wiener System model for arterial pulse transmission.

Numerous linear dynamic models exist for describing the arterial pulse transmission phenomenon. We introduce a novel Wiener system based model in which a linear filter representing large arteries is coupled with a hysteresis-free nonlinear function representing complex wave transmission of branching arteries and the periphery. Experimental datasets (n = 7) are used to first estimate the Wiener model with linear, quadratic and cubic function for the aorta to radial artery pulse transmission and aorta to femoral artery pulse transmission. To model the nonlinear memoryless monotonic function in the Wiener System model, a correlation study is performed for linear finite impulse response (FIR) filter simulated peripheral pressure vs. measured peripheral pressure waveform. Each of this correlation curves were fitted to linear, quadratic and cubic polynomial equation. Wiener model is then simulated for aortic-to-radial artery as well as aortic-to-femoral artery to reconstruct radial and femoral pressure waveform. It was found that Wiener model with 3rd order polynomial function yielded better modeling accuracy (with average RMSE = 2.187 mmHg for radial and 4.281 mmHg for femoral pressure) than that from 2nd order polynomial function (with average RMSE = 2.242 mmHg for radial and 4.355 mmHg for femoral pressure) which in turn was better than mere linear FIR filter (with average RMSE = 2.604 mmHg for radial and 4.810 mmHg for femoral pressure).

Educational gaps among healthcare providers: an institution needs assessment to improve pain management for postsurgical patients.

OBJECTIVE: Nurses should be educated in pain management because they are more likely than other healthcare professionals to educate patients about their pain. The authors sought to identify the knowledge gaps in postoperative pain management among postsurgical nursing staff and the existence of institutional policies and educational programs to support them in delivering optimal pain management services. SETTING: Academic hospital. PARTICIPANTS: Two hundred seventy-seven registered nurses, nurse practitioners, nurse managers, physician assistants, and other health professionals. INTERVENTIONS: Nurses participated in an online, anonymous survey that consisted of 43 questions in two broad categories: (1) knowledge and attitudes about pain management and (2) institutional pain management and assessment. MAIN OUTCOME MEASURE: Knowledge base of surgical nursing staff regarding postoperative pain management. RESULTS: The overall mean knowledge score was 44.84 percent, with the highest percent of correct answers in the cancer pain category (54.03 percent). Recognition of signs and symptoms of pain had the lowest correct response rate (40.91 percent). Forty-nine percent of respondents reported that pain management protocols tailored to the specific population treated were available, 42 percent reported that patient pain education was always performed, 29 percent reported that they received regular training about pain management, and 17 percent had access to national pain management guidelines. CONCLUSION: The survey results demonstrate general gaps in pain management knowledge among nurses, particularly in recognizing signs and symptoms of pain. This work may guide the development of programs that improve postoperative pain management by increasing the frequency of nurses' pain education and improving the availability of pain-related policies and protocols.

The effect of sedation on the accuracy and treatment outcomes for diagnostic injections: a randomized, controlled, crossover study.

BACKGROUND AND OBJECTIVE: Diagnostic injections are used to diagnose myriad pain conditions, but are characterized by a high false-positive rate. One potential cause of inaccurate diagnostic blocks is the use of sedation. We sought to determine the effect of sedation on the validity of diagnostic injections. DESIGN: Randomized, crossover study in which 73 patients were allocated to receive a diagnostic sacroiliac joint or sympathetic nerve block performed either with or without sedation using midazolam and fentanyl. Those who obtained equivocal relief, good relief lasting less than 3 months, or who were otherwise deemed good candidates for a repeat injection, received a subsequent crossover injection within 3 months (N = 46). SETTING AND PATIENTS: A tertiary care teaching hospital and a military treatment facility. RESULTS: In the primary crossover analysis, blocks performed with sedation resulted in a larger mean reduction in pain diary score than those done without sedation (1.2 [2.6]; P = 0.006), less procedure-related pain (difference in means 2.3 [2.5]; P < 0.0001), and a higher proportion of patients who obtained > 50% pain relief on their pain diaries (70% vs. 54%; P = 0.039). The increased pain reduction was not accompanied by increased satisfaction (sedation mean 3.9 [1.1] vs. 3.7 [1.3]; P = 0.26). Similar findings were observed for the parallel group (N = 73) and omnibus (all sedation vs. no sedation blocks, N = 110) analyses. No differences in outcomes were noted between the use and non-use of sedation at 1-month. CONCLUSIONS: The use of sedation during diagnostic injections may increase the rate of false-positive blocks and lead to misdiagnoses and unnecessary procedures, but has no effect on satisfaction or outcomes at 1-month.

Pediatric cervical spondylolysis and American football.

BACKGROUND CONTEXT: Cervical spondylolysis (CS) is a rare condition and is even more uncommon in pediatric patients. It is characterized by a disruption of the articular mass at the junction of the superior and inferior facet joints and often is diagnosed incidentally. The C6 level is most commonly involved, and the cause of CS remains unknown. There are no recommendations in the literature regarding activity modification in patients with CS and no discussion as to risks of participation in American football or other contact sports. PURPOSE: To report a case of C6 bilateral cervical spondylolysis with bicuspid spinous process and to discuss radiographic/clinical findings and issues related to participation in contact sports and minimizing the risk of spinal cord injury. STUDY DESIGN/SETTING: Case report with 6 months clinical/radiographic follow-up METHODS: Radiographic description, clinical findings, and current review of the literature. RESULTS: A pediatric patient presented with a bilateral C6 cervical spondylolysis and bicuspid spinous process after an American football-related minor cervical spine trauma. Findings on radiographs indicated that the spondylolysis appeared to be chronic in nature, without evidence of instability. The patient and his family were educated on ways to decrease the risk of spinal cord injury with contact sports, after which the patient was allowed to participate fully in sports without restrictions or adverse events. CONCLUSION: Pediatric cervical spondylolysis is a rare condition, the cause of which remains debated. Although there is theoretical risk, more than 1.5 million youth participate in American football annually, and there have been no reported cases of significant spinal cord injury in patients with CS from football or other contact sports.

Comparing two types of macrolide antibiotics for the purpose of assessing population-based drug interactions.

OBJECTIVE: Clarithromycin strongly inhibits enzyme cytochrome P450 3A4, preventing the metabolism of some other drugs, while azithromycin is a weak inhibitor. Accordingly, blood concentrations of other drugs increase with clarithromycin coprescription leading to adverse events. These macrolide antibiotics also differ on other properties that may impact outcomes. In this study, we compared outcomes in two groups of macrolide antibiotic users in the absence of potentially interacting drugs. DESIGN: Population-based retrospective cohort study. SETTING: Ontario, Canada, from 2003 to 2010. PATIENTS: Patients (mean 74 years) prescribed clarithromycin (n=52 251) or azithromycin (referent group, n=46 618). MAIN OUTCOMES: The primary outcomes were hospital admission within 30 days of a new antibiotic prescription with any of the 12 conditions examined separately (acute kidney injury, acute myocardial infarction, neuroimaging (proxy for delirium), hypotension, syncope, hyperkalaemia, hyponatraemia, hyperglycaemia, arrhythmia, ischaemic stroke, gastrointestinal bleeding and sepsis). The secondary outcome was mortality. RESULTS: The baseline characteristics of the two groups, including patient demographics, comorbid conditions, infection type and prescribing physician specialty, were nearly identical. The median daily dose was 1000 mg for clarithromycin and 300 mg for azithromycin and the median duration of dispensing antibiotics was 10 and 5 days, respectively. There was no difference between the groups in the risk of hospitalisation for any condition studied (relative risk ranged from 0.67 to 1.23). Compared with azithromycin, clarithromycin was associated with a slightly higher risk of all-cause mortality (0.46% vs 0.37%, relative risk 1.25, 95% CI 1.03 to 1.52). CONCLUSIONS: Clarithromycin can be used to assess drug interactions in population-based studies with azithromycin serving as a control group. However, any differences in mortality observed between the two antibiotic groups in the setting of other drug use may be partially attributable to factors beyond the inhibition of drug metabolising enzymes and transporters, as the difference for this outcome was significant.

Statin toxicity from macrolide antibiotic coprescription: a population-based cohort study.

BACKGROUND: Clarithromycin and erythromycin, but not azithromycin, inhibit cytochrome P450 isoenzyme 3A4 (CYP3A4), and inhibition increases blood concentrations of statins that are metabolized by CYP3A4. OBJECTIVE: To measure the frequency of statin toxicity after coprescription of a statin with clarithromycin or erythromycin. DESIGN: Population-based cohort study. SETTING: Ontario, Canada, from 2003 to 2010. PATIENTS: Continuous statin users older than 65 years who were prescribed clarithromycin (n = 72,591) or erythromycin (n = 3267) compared with those prescribed azithromycin (n = 68,478). MEASUREMENTS: The primary outcome was hospitalization with rhabdomyolysis within 30 days of the antibiotic prescription. RESULTS: Atorvastatin was the most commonly prescribed statin (73%) followed by simvastatin and lovastatin. Compared with azithromycin, coprescription of a statin with clarithromycin or erythromycin was associated with a higher risk for hospitalization with rhabdomyolysis (absolute risk increase, 0.02% [95% CI, 0.01% to 0.03%]; relative risk [RR], 2.17 [CI, 1.04 to 4.53]) or with acute kidney injury (absolute risk increase, 1.26% [CI, 0.58% to 1.95%]; RR, 1.78 [CI, 1.49 to 2.14]) and for all-cause mortality (absolute risk increase, 0.25% [CI, 0.17% to 0.33%]; RR, 1.56 [CI, 1.36 to 1.80]). LIMITATIONS: Only older adults were included in the study. The absolute risk increase for rhabdomyolysis may be underestimated because the codes used to identify it were insensitive. CONCLUSION: In older adults, coprescription of clarithromycin or erythromycin with a statin that is metabolized by CYP3A4 increases the risk for statin toxicity. PRIMARY FUNDING SOURCE: Academic Medical Organization of Southwestern Ontario.

The horizon for treating cutaneous vascular lesions.

Dermatologists encounter a wide range of cutaneous vascular lesions, including infantile hemangiomas, port-wine stain birthmarks, arteriovenous malformations, venous malformations, Kaposi sarcomas, angiosarcomas, and angiofibromas. Current treatment modalities to reduce these lesions include topical and/or intralesional steroids, laser therapy, surgical resection, and endovascular therapy. However, each method has limitations owing to recurrence, comorbidities, toxicity, or lesion location. Photodynamic therapy, antiangiogenic therapy, and evolving methods of sclerotherapy are promising areas of development that may mitigate limitations of current treatments and offer exciting options for patients and their physicians.

A survey of United States periodontists' knowledge, attitudes, and behaviors related to tobacco-cessation interventions.

BACKGROUND: Because of the clear causal relationship between smoking and periodontal disease, and the negative effect of smoking on wound healing, it is of great importance to evaluate the tobacco-cessation interventions provided by periodontal practices. The use of tobacco-cessation interventions in clinical practice can be measured by whether the practitioner uses any of the "5 A's" defined by the 2008 United States Public Health Services Clinical Practice Guideline. METHODS: Surveys were mailed to 1,000 active members of the American Academy of Periodontology. The surveys assessed the periodontists' demographic information, educational and professional background, knowledge and attitudes about tobacco cessation, and use of interventions in the daily practice of periodontics. RESULTS: Data were collected from 231 periodontists via a self-administered survey. Most (92%) believed that tobacco cessation is a responsibility of the dental profession. A pattern of declining levels of involvement was seen as the providers moved through the suggested "5 A's" for promoting tobacco cessation. Providers with formal tobacco-cessation training were more likely to perform interventions. The primary perceived barriers to providing tobacco-cessation interventions were low patient acceptance of treatment, lack of time, and lack of training. CONCLUSION: The findings of this study indicate that periodontists believe that tobacco-cessation interventions are a responsibility of the dental profession; however, because of several perceived barriers, reported rates of comprehensive tobacco interventions in periodontal practices are low.

Collateral damage: the effect of patient complications on the surgeon's psyche.

BACKGROUND: The effect of patient complications on physicians is not well understood. Our objective was to determine the impact of a surgeon's complication(s) on his/her emotional state and job performance. METHODS: An anonymous survey was distributed to Midwest Surgical Society members and attending surgeons within the Grand Rapids, Michigan, community. RESULTS: There were 123 respondents (30.5% response rate). For the majority of participants, the first complication that had a significant emotional impact on them occurred during residency (51.2%). Most respondents reported this did not impair their professional functioning (77.2%). If a major complication was first experienced after residency, this had a greater likelihood of causing impairment (P < .05). Surgeons primarily dealt with the emotional impact by discussing it with a surgical partner (87.8%). Alcohol or other substance use increased in 6.5% of those surveyed. Most respondents (58.5%) felt it was difficult to handle the emotional effects of complications throughout their careers and this did not improve with experience. CONCLUSION: The majority of surgeons agreed that it was difficult to handle the emotional effects of complications throughout their careers. Efforts should be made to increase awareness of unrecognized emotional effects of patient complications and improve access to support systems for surgeons.

Surgical or non-surgical periodontal treatment: factors affecting patient decision making.

BACKGROUND: This study explored which factors affected patients' decisions to pursue either surgical or non-surgical periodontal treatment. METHODS: Data were collected from 74 patients at a regularly scheduled periodontal appointment, at which each patient was told that periodontal treatment was needed, and 2 weeks following the actual treatment. The surveys assessed the patients' decisions and potential determinants of these decisions. The dental anxiety scale-revised, the state-trait anxiety inventory, and the Iowa dental control index were used to measure psychosocial factors. RESULTS: Patients who decided to have surgery did not differ from patients who decided against surgery in sociodemographic variables such as gender, age, education, and socioeconomic status, nor in their desire for control over the treatment decision. However, they had less dental fear and less general anxiety than the non-surgery patients. Although the two patient groups did not differ in their responses concerning how well the dentists had informed them about the procedure, they differed in the degree of trust and rapport with their dentists. CONCLUSIONS: The less dentally fearful and anxious patients were in general and the more they trusted their provider and felt they had good rapport, the more likely they were to accept surgical periodontal treatment. These results stress the importance of good patient-provider communication.

The use of concomitant medications in psychiatric inpatients treated with either olanzapine or other antipsychotic agents: a naturalistic study at a state psychiatric hospital.

Concomitant medications are frequently used in the treatment of resistant psychiatric conditions to augment the primary psychotropic agent or to ameliorate side effects. The present study evaluated the prescription of concomitant psychiatric medications for psychiatric inpatients that were prescribed either olanzapine at its first commercial availability or another first-line antipsychotic agent. Sixty-nine newly admitted patients (mainly with schizophrenia) who were prescribed either olanzapine (n = 35) or another first-line antipsychotic agent (n = 34) were assessed (for the prescription of other concomitant psychotropic drugs) before (2-4 weeks prior to study) and following 8 weeks of treatment (unless discharged sooner). The results indicate that significantly fewer olanzapine-treated subjects were prescribed anticholinergic agents as compared to those prescribed other first-line antipsychotic agents, and a similar trend was noted in the prescription of mood stabilizers as well. Olanzapine-treated subjects used less as needed (PRN) antipsychotic medication compared to pre-olanzapine treatment period. Olanzapine-treated subjects used more anxiolytic agents compared to the control group in the early stages of treatment, probably due to the greater baseline severity of illness. These data suggest that olanzapine use is associated with less use of anticholinergic and mood-stabilizing agents as compared to older antipsychotic agents. These results also suggest that there is less need for PRN antipsychotic medication following olanzapine treatment. More severely ill subjects may require more anxiolytics during olanzapine initiation. The need for less anticholinergic and mood-stabilizing agent use with olanzapine could lead to greater adherence to long-term treatment and perhaps decreased cost (i.e. use of blood and organ system monitoring with mood stabilizers). At the end of treatment, olanzapine-treated subjects had statistically significantly lesser concomitant medicine usage compared to control subjects.