The theory of oxygen hemoglobin association.

We develop a theory of oxygen hemoglobin association and derive the oxygen hemoglobin association equation and determine the values of the four association constants by curve fitting four commonly accepted data points that relate oxygen saturation and oxygen partial pressure (PO2) in the blood using mathematical reasoning and chemical kinetics. The four association constants come from the progression of oxygen binding to each of the four subunits on the hemoglobin molecule in a cooperative manner. The binding of oxygen alters the affinity of subsequent binding of additional oxygen molecules, which is reflected in changing magnitudes of the association constants. We also demonstrate rather surprisingly that the value of the third association constant is significantly smaller than all other association constants and offer some conjecture about this puzzling finding. With our equation, we can compute the distributions of all five oxyhemoglobin species at various PO2 levels that are published for the first time in the history of hemoglobin research. After examining the distributions, we find the triply bound oxyhemoglobin exists in very low concentration, consistent with the small third association constant. In addition, we present the oxygen levels where maximal concentrations of various oxyhemoglobin species occur, another unexpected finding that was never published before. Finally, we determine the inflection point of the hemoglobin association curve, a defining property to a specific sigmoid curve, representing the steepest portion of the curve.

A Decade of Prospective Peer Review: Impact on Safety Culture and Lessons Learned in a Multicenter Radiation Medicine Department.

PURPOSE: Quality assurance (QA) is critical to the success of radiation therapy (RT) for patients with cancer and affects clinical outcomes. We report longitudinal findings of a prospective peer review evaluation system implemented at a major academic health system as part of RT QA during a 10-year period. METHODS AND MATERIALS: All cases treated within our department undergo prospective multidisciplinary peer review and are assigned a grade (A, B, or C). "A" cases require no changes, "B" cases require minor modification, and "C" cases require major modification before treatment planning. The z-ratio test for the significance of the difference between the 5-year baseline (2012-2016) and follow-up (2017-2021) period was used to compare grades between the 2 periods. A 2-tailed P value <.05 was considered significant. RESULTS: Of the 20,069 cases, 15,659 (78%) were curative and were analyzed. The fraction of A cases decreased from 74.8% (baseline) to 64.5% (follow-up), whereas B cases increased from 19.4% to 35.4% and C cases decreased from 5.8% to 0.1%. Of the 9 treatment locations, the main hospital site had a higher percentage of A grades relative to community locations in the baseline (78.6% vs 67.8%; P < .002) and follow-up (66.9% vs 62.3%; P < .002) periods. There was a decrease in the percentage of A cases from the baseline to the follow-up period regardless of plan type (complex vs intermediate vs simple). There was a decrease in the percentage of A cases among specialists from baseline to follow-up (78.2% to 67.7%; P < .002) and among generalists from baseline to follow-up (69.7% to 61.7%; P < .002). CONCLUSIONS: Our 10-year experience in contour peer review identified increased opportunities in improving treatment plan quality over time. The drop in A scores and rise in B scores suggests increased scrutiny and findings-based improvements over time, whereas the drop in C scores indicates amelioration of "major failures" addressed in the startup years. Peer review rounds upstream of treatment planning provide valuable RT QA and should be considered by other departments to enhance the quality and consistency of RT.

Advanced diagnostic and therapeutic techniques for anaesthetists in thoracic trauma: an evidence-based review.

Anaesthetists play an important role in the evaluation and treatment of patients with signs of thoracic trauma. Anaesthesia involvement can provide valuable input using both advanced diagnostic and therapeutic interventions. Commonly performed interventions may be complicated in this setting including airway management, damage control resuscitation, and acute pain management. Anaesthetists must consider additional factors including airway injuries, vascular injuries, and coagulopathy when treating this population. This evidence-based review discusses traumatic thoracic injuries with a focus on new interventions and modern anaesthesia techniques. This review further serves to support the early involvement of anaesthetists in the emergency department and other areas where they can provide value to the trauma care pathway.

Development and execution of a pandemic preparedness plan: Therapeutic medical physics and radiation dosimetry during the COVID-19 crisis.

The SARS-CoV-2 coronavirus pandemic has spread around the world including the United States. New York State has been hardest hit by the virus with over 380 000 citizens with confirmed COVID-19, the illness associated with the SARS-CoV-2 virus. At our institution, the medical physics and dosimetry group developed a pandemic preparedness plan to ensure continued operation of our service. Actions taken included launching remote access to clinical systems for all dosimetrists and physicists, establishing lines of communication among staff members, and altering coverage schedules to limit on-site presence and decrease risk of infection. The preparedness plan was activated March 23, 2020, and data were collected on treatment planning and chart checking efficiency for 6 weeks. External beam patient load decreased by 25% during the COVID-19 crisis, and special procedures were almost entirely eliminated excepting urgent stereotactic radiosurgery or brachytherapy. Efficiency of treatment planning and chart checking was slightly better than a comparable 6-week interval in 2019. This is most likely due to decreased patient load: Fewer plans to generate and more physicists available for checking without special procedure coverage. Physicists and dosimetrists completed a survey about their experience during the crisis and responded positively about the preparedness plan and their altered work arrangements, though technical problems and connectivity issues made the transition to remote work difficult. Overall, the medical physics and dosimetry group successfully maintained high-quality, efficient care while minimizing risk to the staff by minimizing on-site presence. Currently, the number of COVID-19 cases in our area is decreasing, but the preparedness plan has demonstrated efficacy, and we will be ready to activate the plan should COVID-19 return or an unknown virus manifest in the future.

Prospective Peer Review in Radiation Therapy Treatment Planning: Long-Term Results From a Longitudinal Study.

PURPOSE: To present the longitudinal results of a prospective peer review evaluation system (PES) before treatment planning. METHODS AND MATERIALS: All cases undergoing radiation therapy (RT) at high-volume academic institutions were graded in daily prospective multidisciplinary contouring rounds (CRs). The clinical suitability for RT, prescription, contours, and written directives were peer reviewed, compared with departmental care pathways, and recorded in a prospective database. Grades were assigned as follows: A (score 4.0) = no deficiencies; B (3.0) = minor modifications of the planning target volume, organs at risk, written directives, or a prescription/care pathway mismatch; and C (2.0) = incomplete target volume or organ-at-risk contours, unsuitable use or inappropriate planned administration of RT, significant contour modifications, prescription changes, or laterality modifications. Information was pooled to determine pretreatment planning work performance by assigning a grade point average (GPA) for each physician as well as compositely. RESULTS: A total of 11,843 treatment plans from 7854 patients were reviewed using the PES from September 2013 to May 2018. Twenty-seven point nine percent of cases (n = 3303) required modifications before treatment planning commenced. The overall breakdown of grades was 72.1% As, 21.7% Bs, and 6.2% Cs. The median physician CR GPA was 3.60 (average 3.7) with a range of 3.0 to 3.9. Seventy-five percent of physicians demonstrated improvement of their CR GPA since inception of the program, and all physicians demonstrated a drop in the percentage of cases that were assigned a grade of C. CONCLUSIONS: The PES can transparently quantify clinical performance in a single metric. The PES was impactful, with 75% of physicians demonstrating improvement in their CR GPA over time. In contrast to traditional chart rounds, this peer review was meaningful when done before planning commenced, a trend that was observed throughout the study period. Twenty-seven point nine percent of all cases required modification before starting treatment planning, and 6.2% of cases required significant remediation.

Impact of Multi-Institutional Prospective Peer Review on Target and Organ-at-Risk Delineation in Radiation Therapy.

PURPOSE: Peer review is an essential component of quality assurance programs in radiation oncology. The purpose of this work was to assess whether peer reviewers recommend expansion or reduction of planning target volumes (PTVs) and organs at risk (OARs) in prospective multidisciplinary daily contour rounds. METHODS AND MATERIALS: The peer group evaluated the appropriateness of PTVs and OARs for each case according to evidence-based departmental directives. We reviewed 7645 cases that presented between September 2013 and March 2017. We isolated recommendations for PTV/OAR modification and classified each as expansion, reduction, both, or indeterminate. Recommendations were analyzed by technique, site, and physician experience. RESULTS: Eight junior and 7 senior radiation oncologists were included. PTV or OAR modifications were recommended for 750 of 7645 prescriptions (9.7%). The peer group recommended PTV modifications for 534 prescriptions (7.0%): There were 309 expansions (57.9%), 115 reductions (21.5%), 15 both (2.8%), and 95 indeterminate (17.8%). Reasons for PTV expansions included increased nodal coverage and inadequate margins as a result of motion. The peer group recommended OAR modifications for 216 prescriptions (2.8%): There were 102 expansions (47.2%), 23 reductions (10.6%), 2 both (0.9%), and 89 indeterminate (41.2%). Reasons for OAR expansions included missing critical structures and inadequate extent as per departmental standardization. Head and neck represented the largest percentage of PTV recommendations (28.8%). Intensity modulated radiation therapy plans received the most PTV and OAR recommendations (66.8% and 74.5%, respectively). The recommendation rate for senior and junior faculty was 43% and 28%, respectively. CONCLUSIONS: Peer review resulted in recommendations for PTV or OAR change for approximately 10% of cases. Expansions of PTV were recommended >2.5 times more often than reductions and >3 times more often than OAR expansions. This general trend was identified for treatment technique, site, and physician experience. Prospective peer review could yield systematically larger volumes, which could affect multicenter clinical trials.

Abdominal wall Type-I complex regional pain syndrome treated effectively with peripheral nerve field stimulation: a case report.

Chronic abdominal wall pain is a well-documented complication of abdominal surgery. However, abdominal wall complex regional pain syndrome (CRPS) is a rare medical condition. We present a case of abdominal wall CRPS and its treatment with peripheral nerve field stimulation (PNfS). A 34-year-old female presented with right periumbilical pain for 2 years. She developed burning, sharp and stabbing pain with allodynia (extremely sensitive to wind and light touch) and erythema or pallor 2 weeks after an exploratory appendectomy. The extensive evaluation ruled out the underlining pathology. After she failed conservative therapies, she underwent a 7-day trial of thoracic spinal cord stimulation (SCS) and abdominal wall PNfS. Thoracic SCS failed to provide pain relief; however, PNfS provided significant relief (>90%) of burning sensation. It has now been 5 years since the PNfS was implanted and she continues to demonstrate substantial pain relief.

Streamlining emergent hand and wrist radiography with a modified four-view protocol.

This study aims to determine whether a modified four-view hand and wrist study performs comparably to the traditional seven views in the evaluation of acute hand and wrist fractures. This retrospective study was approved by the institutional review board with waiver of informed consent. Two hundred forty patients (50 % male; ages 18-92 years) with unilateral three-view hand (posteroanterior, oblique, and lateral) and four-view wrist (posteroanterior, oblique, lateral, and ulnar deviation) radiographs obtained concurrently following trauma were included in this study. Four emergency radiologists interpreted the original seven images, with two radiologists independently evaluating each study. The patients' radiographs were then recombined into four-view series using the three hand images and the ulnar deviated wrist image. These were interpreted by the same radiologists following an 8-week delay. Kappa statistics were generated to measure inter-observer and inter-method agreement. Generalized linear mixed model analysis was performed between the seven- and four-view methods. Of the 480 reports generated in each of the seven- and four-view image sets, 142 (29.6 %) of the seven-view and 126 (26.2 %) of the four-view reports conveyed certain or suspected acute osseous findings. Average inter-observer kappa coefficients were 0.7845 and 0.8261 for the seven- and four-view protocols, respectively. The average inter-method kappa was 0.823. The odds ratio of diagnosing injury using the four-view compared to the seven-view algorithm was 0.69 (CI 0.45-1.06, P = 0.0873). The modified four-view hand and wrist radiographic series produces diagnostic results comparable to the traditional seven views for acute fracture evaluation.

Practice-based evidence to evidence-based practice: building the National Radiation Oncology Registry.

The National Radiation Oncology Registry (NROR), sponsored by the Radiation Oncology Institute and the American Society for Radiation Oncology, is designed to collect standardized information on cancer care delivery among patients treated with radiotherapy in the United States and will focus on patients with prostate cancer. Stakeholders were engaged through a forum that emphasized the need for patient-centered outcomes, minimal data burden, and maximal connectivity to existing registries and databases. An electronic infrastructure is under development to provide connectivity across radiation oncology and hospital information systems. The NROR Gateway features automatic abstraction as well as aggregation of treatment and outcome data. The prostate cancer data dictionary provides standardized elements in four domains: facility, physician, patient, and treatment. The pilot phase will consist of clinical centers chosen to provide a representative mix of radiation treatment modalities, facility types, population-based settings, and regional locations. The initial set of radiation practice metrics includes physician board certification and maintenance, ordering of staging scans, active surveillance discussion, dose prescriptions for low-risk/high-risk disease, radiation fields for low-risk/high-risk disease, image-guided radiation therapy use, androgen deprivation therapy use, post-brachytherapy implant computed tomography dosimetry, collection of toxicity assessments, and longitudinal patient follow-up. The NROR pilot study will provide the framework for expansion to a nationwide electronic registry for radiation oncology.

Development, implementation, and compliance of treatment pathways in radiation medicine.

INTRODUCTION: While much emphasis on safety in the radiation oncology clinic is placed on process, there remains considerable opportunity to increase safety, enhance outcomes, and avoid ad hoc care by instituting detailed treatment pathways. The purpose of this study was to review the process of developing evidence and consensus-based, outcomes-oriented treatment pathways that standardize treatment and patient management in a large multi-center radiation oncology practice. Further, we reviewed our compliance in incorporating these directives into our day-to-day clinical practice. METHODS: Using the Institute of Medicine guideline for developing treatment pathways, 87 disease specific pathways were developed and incorporated into the electronic medical system in our multi-facility radiation oncology department. Compliance in incorporating treatment pathways was assessed by mining our electronic medical records (EMR) data from January 1, 2010 through February 2012 for patients with breast and prostate cancer. RESULTS: This retrospective analysis of data from EMR found overall compliance to breast and prostate cancer treatment pathways to be 97 and 99%, respectively. The reason for non-compliance proved to be either a failure to complete the prescribed care based on grade II or III toxicity (n = 1 breast, 3 prostate) or patient elected discontinuance of care (n = 1 prostate) or the physician chose a higher dose for positive/close margins (n = 3 breast). CONCLUSION: This study demonstrates that consensus and evidence-based treatment pathways can be developed and implemented in a multi-center department of radiation oncology. And that for prostate and breast cancer there was a high degree of compliance using these directives. The development and implementation of these pathways serve as a key component of our safety program, most notably in our effort to facilitate consistent decision-making and reducing variation between physicians.

Repairing interatrial septal defects from the operating room to the cardiac catheterization laboratory: 2D or not 2D?

Uncorrected congenital interatrial septal defect can be found in nearly a third of all adults and are associated with significant morbidity, including pulmonary hypertension, right-heart failure, atrial arrhythmias, and paradoxical embolic stroke. With advancing technology, percutaneous closure of atrial septal defects has become a viable alternative to open surgical repair. In this review, the authors provide 3 examples in which 3-dimensional interventional transesophageal echocardiogram effectively provided more precise visualization of the dynamic surface and geometry of the atrial septum and related structures than 2-dimensional TEE, permitting accurate sizing and repair of the defects.