RESUMO
The oxygen deficit (OD) is the difference between the end-tidal alveolar Po2 and the calculated Po2 of arterial blood based on measured oxygen saturation that acts as a proxy for the alveolar-arterial Po2 difference. Previous work has shown that the alveolar gas meter (AGM100) can measure pulmonary gas exchange, via the OD, in patients with a history of lung disease and in normal subjects breathing 12.5% O2. The present study measured how the OD varied at different values of inspired O2. Healthy subjects were split by age (young 22-31; n = 23; older 42-90; n = 13). Across all inspired O2 levels (12.5, 15, 17.5, and 21%), the OD was higher in the older cohort 10.6 ± 1.0 mmHg compared with the young -0.4 ± 0.6 mmHg (P < 0.0001, using repeated measures ANOVA), the difference being significant at all O2 levels (all P < 0.0001). The OD difference between age groups and its variance was greater at higher O2 values (age × O2 interaction; P = 0.002). The decrease in OD with lower values of inspired O2 in both cohorts is consistent with the increased accuracy of the calculated arterial Po2 based on the O2-Hb dissociation curve and with the expected decrease in the alveolar-arterial Po2 difference due to a lower arterial saturation. The persisting higher OD seen in older subjects, irrespective of the inspired O2, shows that the measurement of OD remains sensitive to mild gas exchange impairment, even when breathing 21% O2.
Assuntos
Oxigênio/administração & dosagem , Oxigênio/metabolismo , Troca Gasosa Pulmonar , Administração por Inalação , Adulto , Fatores Etários , Feminino , Humanos , Masculino , Adulto JovemRESUMO
When using a new noninvasive method for measuring the efficiency of pulmonary gas exchange, a key measurement is the oxygen deficit, defined as the difference between the end-tidal alveolar Po2 and the calculated arterial Po2. The end-tidal Po2 is measured using a rapid gas analyzer, and the arterial Po2 is derived from pulse oximetry after allowing for the effect of the Pco2 on the oxygen affinity of hemoglobin. In the present report we show that the values of end-tidal Po2 and Pco2 are highly reproducible, providing a solid foundation for the measurement of the oxygen deficit. We compare the oxygen deficit with the classical ideal alveolar-arterial Po2 difference (A-aDO2) as originally proposed by Riley, and now extensively used in clinical practice. This assumes Riley's criteria for ideal alveolar gas, namely no ventilation-perfusion inequality, the same Pco2 as arterial blood, and the same respiratory exchange ratio as the whole lung. It transpires that, in normal subjects, the end-tidal Po2 is essentially the same as the ideal value. This conclusion is consistent with the very small oxygen deficit that we have reported in young normal subjects, the significantly higher values seen in older normal subjects, and the much larger values in patients with lung disease. We conclude that this noninvasive measurement of the efficiency of pulmonary exchange is identical in many respects to that based on the ideal alveolar Po2, but that it is easier to obtain.
Assuntos
Artérias/metabolismo , Pulmão/metabolismo , Oxigênio/metabolismo , Troca Gasosa Pulmonar/fisiologia , Dióxido de Carbono/metabolismo , Hemoglobinas/metabolismo , Humanos , Pulmão/fisiopatologia , Pneumopatias/metabolismo , Pneumopatias/fisiopatologia , Oximetria/métodos , RespiraçãoRESUMO
PURPOSE: We sought to characterize patient-oncologist communication and decision making about continuing or limiting systemic therapy in encounters after an initial consultation, with a particular focus on whether and how oncologists foster shared decision making (SDM). METHODS: We performed content analysis of outpatient oncology encounters at two US National Cancer Institute-designated cancer centers audio recorded between November 2010 and September 2014. A multidisciplinary team used a hybrid approach of inductive and deductive coding and theme development. We used a combination of random and purposive sampling. We restricted quantitative frequency counts to the coded random sample but included all sampled encounters in qualitative thematic analysis. RESULTS: Among 31 randomly sampled dyads with three encounters each, systemic therapy decision making was discussed in 90% (84 of 93) encounters. Thirty-four (37%) broached limiting therapy, which 27 (79%) framed as temporary, nine (26%) as completion of a standard regimen, and five (15%) as permanent discontinuation. Thematic analysis of these 93 encounters, plus five encounters purposively sampled for permanent discontinuation, found that (1) patients and oncologists framed continuing therapy as the default, (2) deficiencies in the SDM process (facilitating choice awareness, discussing options, and incorporating patient preferences) contributed to this default, and (3) oncologists use persuasion rather than deliberation when broaching discontinuation. CONCLUSION: In this study of outpatient encounters between patients with advanced cancer and their oncologists, when discussing systemic therapy, there exists a default to continue systemic therapy, and deficiencies in SDM contribute to this default.
Assuntos
Neoplasias , Oncologistas , Tomada de Decisão Compartilhada , Humanos , Oncologia , Neoplasias/epidemiologia , Neoplasias/terapia , Participação do PacienteRESUMO
Aims: Aging is associated with the development of insulin resistance and hypertension which may stem from inflammation induced by accumulation of toxic bacterial DNA crossing the gut barrier. The aim of this study was to identify factors counter-regulating these processes. Taking advantage of the Chromogranin A (CgA) knockout (CgA-KO) mouse as a model for healthy aging, we have identified Vsig4 (V-set and immunoglobulin domain containing 4) as the critical checkpoint gene in offsetting age-associated hypertension and diabetes. Methods and Results: The CgA-KO mice display two opposite aging phenotypes: hypertension but heightened insulin sensitivity at young age, whereas the blood pressure normalizes at older age and insulin sensitivity further improves. In comparison, aging WT mice gradually lost glucose tolerance and insulin sensitivity and developed hypertension. The gut barrier, compromised in aging WT mice, was preserved in CgA KO mice leading to major 35-fold protection against bacterial DNA-induced inflammation. Similarly, RNA sequencing showed increased expression of the Vsig4 gene (which removes bacterial DNA) in the liver of 2-yr-old CgA-KO mice, which may account for the very low accumulation of microbial DNA in the heart. The reversal of hypertension in aging CgA-KO mice likely stems from (i) low accumulation of microbial DNA, (ii) decreased spillover of norepinephrine in the heart and kidneys, and (iii) reduced inflammation. Conclusion: We conclude that healthy aging relies on protection from bacterial DNA and the consequent low inflammation afforded by CgA-KO. Vsig4 also plays a crucial role in "healthy aging" by counteracting age-associated insulin resistance and hypertension.
Assuntos
Diabetes Mellitus , Microbioma Gastrointestinal , Hipertensão , Resistência à Insulina , Camundongos , Animais , Resistência à Insulina/genética , DNA Bacteriano , Camundongos Knockout , Hipertensão/genética , DNA , Cromogranina A , Inflamação/genéticaRESUMO
Importance: Early discussion of end-of-life (EOL) care preferences improves clinical outcomes and goal-concordant care. However, most EOL discussions occur approximately 1 month before death, despite most patients desiring information earlier. Objective: To describe successful navigation and missed opportunities for EOL discussions (eg, advance care planning, palliative care, discontinuation of disease-directed treatment, hospice care, and after-death wishes) between oncologists and outpatients with advanced cancer. Design, Setting, and Participants: This study is a secondary qualitative analysis of outpatient visits audio-recorded between November 2010 and September 2014 for the Studying Communication in Oncologist-Patient Encounters randomized clinical trial. The study was conducted at 2 US academic medical centers. Participants included medical, gynecological, and radiation oncologists and patients with stage IV malignant neoplasm, whom oncologists characterized as being ones whom they " would not be surprised if they were admitted to an intensive care unit or died within one year." Data were analyzed between January 2018 and August 2020. Exposures: The parent study randomized participants to oncologist- and patient-directed interventions to facilitate discussion of emotions. Encounters were sampled across preintervention and postintervention periods and all 4 treatment conditions. Main Outcomes and Measures: Secondary qualitative analysis was done of patient-oncologist dyads with 3 consecutive visits for EOL discussions, and a random sample of 7 to 8 dyads from 4 trial groups was analyzed for missed opportunities. Results: The full sample included 141 patients (54 women [38.3%]) and 39 oncologists (8 women [19.5%]) (mean [SD] age for both patients and oncologists, 56.3 [10.0] years). Of 423 encounters, only 21 (5%) included EOL discussions. Oncologists reevaluated treatment options in response to patients' concerns, honored patients as experts on their goals, or used anticipatory guidance to frame treatment reevaluation. In the random sample of 31 dyads and 93 encounters, 35 (38%) included at least 1 missed opportunity. Oncologists responded inadequately to patient concerns over disease progression or dying, used optimistic future talk to address patient concerns, or expressed concern over treatment discontinuation. Only 4 of 23 oncologists (17.4%) had both an EOL discussion and a missed opportunity. Conclusions and Relevance: Opportunities for EOL discussions were rarely realized, whereas missed opportunities were more common, a trend that mirrored oncologists' treatment style. There remains a need to address oncologists' sensitivity to EOL discussions, to avoid unnecessary EOL treatment.
Assuntos
Planejamento Antecipado de Cuidados/estatística & dados numéricos , Comunicação , Neoplasias/psicologia , Planejamento de Assistência ao Paciente/estatística & dados numéricos , Relações Médico-Paciente , Assistência Terminal/psicologia , Assistência Terminal/estatística & dados numéricos , Adulto , Idoso , Idoso de 80 Anos ou mais , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Oncologistas/psicologia , Oncologistas/estatística & dados numéricos , Pacientes/psicologia , Pacientes/estatística & dados numéricos , Pesquisa Qualitativa , Estados UnidosRESUMO
BACKGROUND: Chordomas are rare malignant neoplasms that develop from the primitive notochord with < 5% of the tumors occurring in pediatric patients younger than the age of 20. Of these pediatric chordomas, those affecting the craniocervical junction (C1-C2) are even more rare; therefore, parameters for surgical management of these pediatric tumors are not well characterized. OBSERVATIONS: In this case, a 3-year-old male was found to have a clival chordoma on imaging with extension to the craniocervical junction resulting in spinal cord compression. Endoscopic-assisted transoral transclival approach for clival tumor resection was performed first. As a second stage, the patient underwent a left-sided far lateral craniotomy and cervical laminectomy for resection of the skull base chordoma and instrumented fusion of the occiput to C3. He made excellent improvements in strength and dexterity during rehab and was discharged after 3 weeks. LESSONS: In pediatric patients with chordoma with extension to the craniocervical junction and spinal cord compression, decompression with additional occipito-cervical fusion appears to offer a good clinical outcome. Fusion performed as a separate surgery before or at the same time as the initial tumor resection surgery may lead to better outcomes.
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[Figure: see text].