Thulio M. Cunha

Effects of oxygen supplementation on cerebral oxygenation during exercise in chronic obstructive pulmonary disease patients not entitled to long-term oxygen therapy.

Background:  The rate of change (Δ) in cerebral oxygenation (COx) during exercise is influenced by blood flow and arterial O2 content (CaO2). It is currently unclear whether ΔCOx would (i) be impaired during exercise in patients with chronic obstructive pulmonary disease (COPD) who do not fulfil the current criteria for long‐term O2 therapy but present with exercise‐induced hypoxaemia and (ii) improve with hyperoxia (FIO2 = 0·4) in this specific sub‐population.

Dynamics of chest wall volume regulation during constant work rate exercise in patients with chronic obstructive pulmonary disease

This study evaluated the dynamic behavior of total and compartmental chest wall volumes [(VCW) = rib cage (VRC) + abdomen (VAB)] as measured breath-by-breath by optoelectronic plethysmography during constant-load exercise in patients with stable chronic obstructive pulmonary disease. Thirty males (GOLD stages II-III) underwent a cardiopulmonary exercise test to the limit of tolerance (Tlim) at 75% of peak work rate on an electronically braked cycle ergometer. Exercise-induced dynamic hyperinflation was considered to be present when end-expiratory (EE) VCW increased in relation to resting values. There was a noticeable heterogeneity in the patterns of VCW regulation as EEVCW increased non-linearly in 17/30 “hyperinflators” and decreased in 13/30 “non-hyperinflators” (P < 0.05). EEVAB decreased slightly in 8 of the “hyperinflators”, thereby reducing and slowing the rate of increase in end-inspiratory (EI) VCW (P < 0.05). In contrast, decreases in EEVCW in the “non-hyperinflators” were due to the combination of stable EEVRC with marked reductions in EEVAB. These patients showed lower EIVCW and end-exercise dyspnea scores but longer Tlim than their counterparts (P < 0.05). Dyspnea increased and Tlim decreased non-linearly with a faster rate of increase in EIVCW regardless of the presence or absence of dynamic hyperinflation (P < 0.001). However, no significant between-group differences were observed in metabolic, pulmonary gas exchange and cardiovascular responses to exercise. Chest wall volumes are continuously regulated during exercise in order to postpone (or even avoid) their migration to higher operating volumes in patients with COPD, a dynamic process that is strongly dependent on the behavior of the abdominal compartment.

Exercise Capacity in Polycystic Kidney Disease

BACKGROUND Reports about exercise performance in autosomal dominant polycystic kidney disease (ADPKD) are scarce. We aimed to evaluate exercise capacity and levels of nitric oxide and asymmetric dimethylarginine (ADMA) in normotensive patients with ADPKD. STUDY DESIGN Prospective controlled cohort study. SETTING & PARTICIPANTS 26 patients with ADPKD and 30 non-ADPKD control participants (estimated glomerular filtration rate>60 mL/min/1.73 m2, aged 19-39 years, and blood pressure [BP]<140/85 mmHg). We excluded smokers, obese people, and individuals with associated diseases. PREDICTOR ADPKD versus control. OUTCOMES Exercise capacity and nitric oxide and ADMA levels in response to exercise. MEASUREMENTS Cardiopulmonary exercise testing and serum and urinary nitric oxide, plasma ADMA, and BP levels before and after exercise. RESULTS Mean basal systolic and diastolic BP, estimated glomerular filtration rate, and age did not differ between the ADPKD and control groups (116±12 vs. 110±11 mmHg, 76±11 vs 71±9 mmHg, 113±17 vs. 112±9.6 mL/min/1.73 m2, and 30±8 vs. 28.9±7.3 years, respectively). Peak oxygen uptake and anaerobic threshold were significantly lower in the ADPKD group than in controls (22.2±3.3 vs. 31±4.8 mL/kg/min [P<0.001] and 743.6±221 vs. 957.4±301 L/min [P=0.01], respectively). Postexercise serum and urinary nitric oxide levels in patients with ADPKD were not significantly different from baseline (45±5.1 vs. 48.3±4.6 μmol/L and 34.7±6.5 vs. 39.8±6.8 μmol/mg of creatinine, respectively), contrasting with increased postexercise values in controls (63.1±1.9 vs. 53.9±3.1 μmol/L [P=0.01] and 61.4±10.6 vs. 38.7±5.6 μmol/mg of creatinine [P=0.01], respectively). Similarly, whereas postexercise ADMA level did not change in the ADPKD group compared to those at rest (0.47±0.04 vs. 0.45±0.02 μmol/L [P=0.6]), it decreased in controls (0.39±0.02 vs. 0.47±0.02 μmol/L [P=0.006]), as expected. A negative correlation between nitric oxide and ADMA levels after exercise was found in only the control group (r = -0.60; P<0.01). LIMITATIONS Absence of measurements of flow-mediated dilatation and oxidative status. CONCLUSIONS We found lower aerobic capacity in young normotensive patients with ADPKD with preserved kidney function and inadequate responses of nitric oxide and ADMA levels to acute exercise, suggesting the presence of early endothelial dysfunction in this disease.

Bloodstream Infection: The Influence of Risk Factors, Etiology and Antimicrobial Therapy on Mortality Rates

Introduction: Inappropriate initial antimicrobial therapy leads to higher mortality in patients with bloodstream infection. This study aimed to evaluate the relationship between risk factors, etiology and antimicrobial therapy on mortality rates of patients with bloodstream infection. Methods: Between January 2016 to December 2016, 167 patients with bloodstream infection were prospectively evaluated according to the presence or absence of inappropriate antimicrobial therapy of infection. Hospital mortality was the main outcome variable compared between the two study groups. Results: Infected patients who received inappropriate antimicrobial therapy had statistically more diabetes mellitus, chronic obstructive pulmonary disease, chronic renal disease and death than infected patients who initially received appropriate antimicrobial therapy. Loading dose error and error in starting antimicrobial administration were the most frequently detected error in our study and both were determinant factors related to increased mortality. Initial antimicrobial therapy was maintained, escalation and de-escalation 67.6%, 22.7% and 9.6% of cases, respectively. Coagulase negative staphylococci represented the majority reaching 40.7% and multi-drug resistant microorganisms were detected in 27.3% of infections. There was no observed difference in mortality rates among infections caused by resistant or susceptible microorganisms. Conclusion: Loading dose error and error in starting antimicrobial administration, were the most frequently detected error in our study and both were determinant factors related to increased mortality. Beside the multiple logistic regression analysis revealed that the delay in starting antimicrobial therapy was the only independent factor that increased mortality.

Doppler echocardiographic evaluation of hemodynamic effects of applying bilevel positive airway pressure

Introduction: Application of noninvasive positive airway pressure triggers significant cardiopulmonary interactions. Objective: This study aimed to identify the hemodynamic effects arising from the application of bilevel pressure to the airways evaluated by echocardiography. Methods: Randomized, double-blind, controlled study was conducted with 19 healthy participants. Random sequence of three expiratory positive airway pressures (EPAPs) was applied for 5 minutes each. The inspiratory pressure remained constant at 5 cmH2O above the established EPAP. Hemodynamic variables, determined using Doppler echocardiography, a non-invasive ventilator, and a heart monitor were recorded. Results: Comparing baseline data with that collected under various EPAPs of 5, 10, and 15 cmH2O showed reduced aortic velocity time integral (p Conclusion: The cardiopulmonary and interventricular repercussions by echocardiography, were expressed by reducing the left ventricular preload and increasing the biventricular preload, stroke volume, and cardiac output, ensuring increased tidal volume and blood oxygenation.