Covid-19 ­ uso racional do gás oxigênio (O2) / Covid-19 - rational use of oxygen gas (O2)

A pandemia do novo coronavírus trouxe grande sobrecarga aos sistemas de saúde de todo o mundo, especialmente aos países de baixa e média renda (BONG CL et al, 2020). O atraso da vacinação tem agravado a situação nestes países, aumentando o índice de novos casos e a mortalidade pela doença (WHO, 2021). Um dos problemas enfrentados tem sido a escassez da oferta de oxigênio (O2) hospitalar. Agências internacionais como Wellcome Trust, Unitaid e MS criaram uma força tarefa em busca de uma resposta emergencial para a situação, estimando a necessidade de um aporte financeiro de cerca de 90 milhões de dólares, a fim de se evitar mortes preveníveis pela falta de oxigênio para o manejo clínico dos pacientes hospitalizados por COVID-19 (USHER AD, 2021).

The pandemic of the new coronavirus has brought great burden to health systems around the world, especially to low- and middle-income countries (BONG CL et al, 2020). The delay of vaccination has aggravated the situation in these countries, increasing the rate of new cases and mortality from the disease (WHO, 2021). One of the problems faced has been the scarcity of hospital oxygen (O2) supply. International agencies such as Wellcome Trust, Unitaid and MS have set up a task force in search of an emergency response to the situation, estimating the need for a financial contribution of about US$90 million in order to avoid preventable deaths from the lack of oxygen for the clinical management of patients hospitalized by COVID-19 (USHER AD, 2021).

Does low serum TSH within the normal range have negative impact on physical exercise capacity and quality of life of healthy elderly people?

Objective Investigate the differences in cardiopulmonary (CP) capacity and Quality of Life (QOL) between healthy elderly (≥ 65 years) with different TSH levels (< 1.0 and ≥ 1.0 μIU/mL) both within the normal range. Also, evaluate the effects of TSH elevation on CP test and QOL, by administering methimazole to subjects with initial lower-normal TSH, in order to elevate it to superior-normal limit. Materials and methods Initially, a cross-sectional study was performed to compare CP capacity at peak exercise and QOL (using WHOQOL-OLD questionnaire) between healthy seniors (age ≥ 65 years) with TSH < 1.0 μIU/mL vs. TSH ≥1.0 μIU/mL. In the second phase, participants with TSH < 1.0 μIU/mL were included in a non-controlled-prospective-interventional study to investigate the effect of TSH elevation, using methimazole, on QOL and CP capacity at peak exercise. Results From 89 elderly evaluated, 75 had TSH ≥ 1 μIU/mL and 14 TSH < 1 μIU/mL. The two groups had similar basal clinical characteristics. No difference in WHOQOL-OLD scores was observed between groups and they did not differ in terms of CP function at peak exercise. QOL and CP variables were not correlated with TSH levels. Twelve of 14 participants with TSH < 1.0 μIU/mL entered in the prospective study. After one year, no significant differences in clinical caracteristics, QOL, and CP variables were detected in paired analysis before and after methimazole intervention. Conclusions We found no differences in CP capacity and QOL between health elderly with different TSH levels within normal range and no impact after one year of methimazole treatment. More prospective-controlled-randomized studies are necessary to confirm or not the possible harm effect in normal low TSH.

Effect of Nebivolol on MIBG Parameters and Exercise in Heart Failure with Normal Ejection Fraction / Efeito do Nebivolol sobre Parâmetros do MIBG e Exercício na Insuficiência Cardíaca com Fração de Ejeção Normal

Abstract Background: More than 50% of the patients with heart failure have normal ejection fraction (HFNEF). Iodine-123 metaiodobenzylguanidine (123I-MIBG) scintigraphy and cardiopulmonary exercise test (CPET) are prognostic markers in HFNEF. Nebivolol is a beta-blocker with vasodilating properties. Objectives: To evaluate the impact of nebivolol therapy on CPET and123I-MIBG scintigraphic parameters in patients with HFNEF. Methods: Twenty-five patients underwent 123I-MIBG scintigraphy to determine the washout rate and early and late heart-to-mediastinum ratios. During the CPET, we analyzed the systolic blood pressure (SBP) response, heart rate (HR) during effort and recovery (HRR), and oxygen uptake (VO2). After the initial evaluation, we divided our cohort into control and intervention groups. We then started nebivolol and repeated the tests after 3 months. Results: After treatment, the intervention group showed improvement in rest SBP (149 mmHg [143.5-171 mmHg] versus 135 mmHg [125-151 mmHg, p = 0.016]), rest HR (78 bpm [65.5-84 bpm] versus 64.5 bpm [57.5-75.5 bpm, p = 0.028]), peak SBP (235 mmHg [216.5-249 mmHg] versus 198 mmHg [191-220.5 mmHg], p = 0.001), peak HR (124.5 bpm [115-142 bpm] versus 115 bpm [103.7-124 bpm], p= 0.043), HRR on the 1st minute (6.5 bpm [4.75-12.75 bpm] versus 14.5 bpm [6.7-22 bpm], p = 0.025) and HRR on the 2nd minute (15.5 bpm [13-21.75 bpm] versus 23.5 bpm [16-31.7 bpm], p = 0.005), but no change in peak VO2 and 123I-MIBG scintigraphic parameters. Conclusion: Despite a better control in SBP, HR during rest and exercise, and improvement in HRR, nebivolol failed to show a positive effect on peak VO2 and 123I-MIBG scintigraphic parameters. The lack of effect on adrenergic activity may be the cause of the lack of effect on functional capacity.

Resumo Fundamento: Mais de 50% dos pacientes com insuficiência cardíaca têm fração de ejeção preservada (ICFEN). A cintilografia marcada com iodo 123 com metaiodobenzilguanidina (123I-MIBG) e o teste cardiopulmonar do exercício (TCPE) são marcadores de prognóstico da ICFEN. O nebivolol é um betabloqueador com propriedade vasodilatadora. Objetivos: Avaliar o impacto da terapia com nebivolol sobre as variáveis da cintilografia com 123I-MIBG e do TCPE em pacientes com ICFEN. Métodos: Vinte e cinco pacientes realizaram cintilografia com 123I-MIBG para avaliar a taxa de washout e a relação coração/mediastino precoce e tardia. Durante o TCPE, foi analisado o comportamento da pressão arterial sistólica (PAS), frequência cardíaca (FC) durante o esforço e a recuperação (FCR) e o consumo de oxigênio (VO2). Após avaliação inicial, separamos nossa amostra em grupos controle versus intervenção, iniciamos o nebivolol e repetimos os exames após 3 meses. Resultados: Após o tratamento, o grupo intervenção apresentou melhora na PAS (149 mmHg [143,5-171 mmHg] versus 135 mmHg [125-151 mmHg, p = 0,016]), FC em repouso (78 bpm [65,5-84 bpm] versus 64,5 bpm [57,5-75,5 bpm, p = 0,028]), PAS no pico do esforço (235 mmHg [216,5-249 mmHg] versus 198 mmHg [191-220,5 mmHg], p = 0,001), FC no pico do esforço (124,5 bpm [115-142 bpm] versus 115 bpm [103,7-124 bpm], p = 0,043) e FCR no 1º minuto (6,5 bpm [4,75-12,75 bpm] versus 14,5 bpm [6,7-22 bpm], p = 0,025) e no 2º minuto (15,5 bpm [13-21,75 bpm] versus 23,5 bpm [16-31,7 bpm], p = 0,005), porém não apresentou mudança no VO2 de pico e nos parâmetros da cintilografia com 123I-MIBG. Conclusão: Apesar de um melhor controle da PAS e na FC em repouso e durante o esforço e uma melhora na FCR, o nebivolol não ocasionou efeito positivo sobre o VO2 de pico e nos parâmetros da cintilografia com 123I-MIBG. A ausência de efeito sobre a atividade adrenérgica pode ser a causa da falta de efeito sobre a capacidade funcional.

The effect of acute magnesium loading on the maximal exercise performance of stable chronic obstructive pulmonary disease patients

OBJECTIVE: The potential influence of magnesium on exercise performance is a subject of increasing interest. Magnesium has been shown to have bronchodilatatory properties in asthma and chronic obstructive pulmonary disease patients. The aim of this study was to investigate the effects of acute magnesium IV loading on the aerobic exercise performance of stable chronic obstructive pulmonary disease patients. METHODS: Twenty male chronic obstructive pulmonary disease patients (66.2 + 8.3 years old, FEV1: 49.3+19.8%) received an IV infusion of 2 g of either magnesium sulfate or saline on two randomly assigned occasions approximately two days apart. Spirometry was performed both before and 45 minutes after the infusions. A symptom-limited incremental maximal cardiopulmonary test was performed on a cycle ergometer at approximately 100 minutes after the end of the infusion. ClinicalTrials.gov: NCT00500864 RESULTS: Magnesium infusion was associated with significant reductions in the functional residual capacity (-0.41 l) and residual volume (-0.47 l), the mean arterial blood pressure (-5.6 mmHg) and the cardiac double product (734.8 mmHg.bpm) at rest. Magnesium treatment led to significant increases in the maximal load reached (+8 w) and the respiratory exchange ratio (0.06) at peak exercise. The subgroup of patients who showed increases in the work load equal to or greater than 5 w also exhibited significantly greater improvements in inspiratory capacity (0.29 l). CONCLUSIONS: The acute IV loading of magnesium promotes a reduction in static lung hyperinflation and improves the exercise performance in stable chronic obstructive pulmonary disease patients. Improvements in respiratory mechanics appear to be responsible for the latter finding.

Efeito do estradiol sobre as respostas cardiopulmonar e metabólica em mulheres normotensas após a menopausa submetidas à cicloergoespirometria / Effect of estradiol on cardiopulmonary and metabolic responses of postmenopausal normotensive women undergoing cardiopulmonary exercise testing

OBJETIVO: Avaliar pela cicloergoespirometria as respostas cardiopulmonar e metabólica, em 30 usuárias de estrogênio após a menopausa, durante exercício físico máximo, sendo que 25 completaram o estudo. MÉTODOS: Em estudo prospectivo, duplo-cego, randomizado, controlado por placebo foram avaliados dois grupos de mulheres: um, constituído por 14 mulheres (57,6±4,8 anos) após a menopausa, usuárias de estradiol na dose de 2 mg/dia por via oral durante 90 dias, e, outro, por 11 mulheres (55,8±6,7 anos) usuárias de placebo no mesmo período. Ambos os grupos foram submetidos a testes cicloergoespirométricos e analisadas as variáveis: volume de oxigênio consumido por kg/min no pico do exercício (VO2 pico), limiar anaeróbio (LA), volume de oxigênio consumido por Kg/min no limiar anaeróbio (VO2 no LA), ponto de descompensação respiratória (PDR), tempo de exercício (TE), carga máxima atingida (CM), freqüência cardíaca máxima (FC), pressão arterial sistólica (PAS), pressão arterial diastólica (PAD), antes e após administração dos medicamentos. RESULTADOS: Constataram-se reduções estatisticamente significantes em VO2 pico (p=0,002), LA (p=0,01), VO2 no LA (p=0,001) e TE (p=0,05) somente no grupo de usuárias de estradiol. As outras variáveis não sofreram alterações. CONCLUSÃO: O estradiol não promoveu melhora nas respostas cardiopulmonar e metabólica, quando comparado ao placebo.