Efeitos da posição sentada na força de músculos respiratórios durante o desmame de pacientes sob ventilação mecânica prolongada no pós-operatório de cirurgia cardiovascular

O objetivo do estudo foi investigar os efeitos da posição sentada, nos parâmetros ventilatórios e hemodinâmicos, em pacientes com suporte ventilatório mecânico prolongado, estáveis hemodinamicamente. Participaram do estudo 40 pacientes que foram randomizados em grupo controle (n=17) e grupo intervenção (n=23). Foram mensurados parâmetros hemodinâmicos, gasometria arterial, força muscular respiratória e ventilometria, realizados em dois momentos: primeira e segunda avaliação, com intervalo de 30 minutos entre as medidas. No grupo controle, as duas avaliações foram realizadas no leito, com a cabeceira elevada a 30°. No grupo intervenção, a primeira avaliação foi realizada no leito (30°) e a segunda, 30 minutos após transferência para a poltrona, na posição sentada (90°). A idade média da amostra foi de 64,7±11,2 anos. O resultado do estudo demonstrou que não houve diferenças em relação às variáveis, hemodinâmicas, gasométricas, capacidade vital forçada, volume minuto e volume de ar corrente. Entretanto, ocorreu aumento significativo da pressão inspiratória máxima (PImáx) no grupo intervenção (pThe purpose was to study the effects of sitting position, in ventilatory and hemodynamic parameters, in patients under prolonged mechanical ventilation, in the postoperative of cardiovascular surgery. Participated 40 postoperative cardiovascular patients, intubated and mechanically ventilated, were randomized into control group (n=17) and intervention group (n=23). Hemodynamic parameters, arterial blood gases, respiratory muscle strength and ventilometry, were measured in two moments: first and second evaluation, with 30-minute interval between measurements. In the control group, both evaluations were performed at head of the bed elevated at 30°. In the sitting group, the first evaluation was developed at 30° and the second, (30 minutes after transfer to the armchair) in the sitting position (90°). The mean age of patients was 64.7±11.2 years. There were no differences regarding the hemodynamic parameters, blood gas analysis, forced vital capacity, minute ventilation and tidal volume. However, a significant increase in maximal inspiratory pressure (MIP) in the intervention group was observed (p<0.01). We conclude that stable patients in the postoperative period of cardiovascular surgery, mechanically ventilated, maybe benefits of the sitting position observed of increased inspiratory muscle strength. Furthermore, no significant hemodynamic changes, and it was well tolerated when the patients were transferred to the sitting position, so it was considered a safe procedure

Effects of PEEP on inspiratory and expiratory mechanics in adult respiratory distress syndrome

The purpose of the present study was to assess the mechanical behavior of the respiratory system separately during inspiration and expiration in adult respiratory distress syndrome (ARDS) and the influence of PEEP on any phasic variations of the mechanical respiratory parameters. Airways pressure (P), flow (V), and volume (V) signals were recorded in nine patients with ARDS and 10 patients without known respiratory disorder (control group). All patients were artificially ventilated at three levels of positive end-expiratory pressure (PEEP): 0, 5, and 10 hPa. Data were analyzed separately for inspiratory and expiratory records using multiple linear regression analysis (MLRA) according to the equation: P=Ers V + Rrs V’ + P-0, where Ers and Rrs represent, respectively, the intubated respiratory system elastance and resistance, and P-0 the end-expiratory pressure. In the ARDS group expiratory Ers (Ers(EXP)=45.58 +/- 4.24 hPa/L) was substantially higher (p &lt; 0.01) than inspiratory Ers (Ers(INSP)=36.76 +/- 2.55) with a marked effect of applied PEEP in diminishing the difference between Ers(EXP) and Ers(INSP) (P &lt; 0.01). For the ARDS group inspiratory Rrs (Rrs(INSP)) decreased significantly with increasing PEEP (PEEP=0: Rrs(INSP)=1643, PEEP=10: Rrs(INSP)=13.28, p &lt; 0.01). The found differences between Ers(EXP) and Ers(INSP) could be attributable to an influence of mechanical ventilation by positive airway pressure on pulmonary edema and interstitial fluid during the inspiratory phase of the respiratory cycle. (C) 2002 Elsevier Science Ltd, All rights reserved

Early phase changes by concurrent endurance and strength training

To compare regimens of concurrent strength and endurance training, 26 male basketball players were matched for stature, body composition, and physical activity level. Subjects completed different training programs for 7 weeks, 4 days per week. Groups were as follows: (a) the strength group (S; n = 7) did strength training; (b) the endurance group (E; n = 7) did endurance training; (c) the strength and endurance group (S + E; n = 7) combined strength and endurance training; and (d) the control group (Q n = 5) had no training. The S + E group showed greater gains in Vo(2)max than the E group did (12.9% vs. 6.8%), whereas the S group showed a decline (8.8%). Gains were noted in strength and vertical jump performance for the S + E and S groups. The S + E group had better posttraining anaerobic power than the S group did (6.2% vs. 2.9%). No strength, power, or anaerobic power gains were present for the E and C groups. We conclude that concurrent endurance and strength training is more effective in terms of improving athletic performance than are endurance and strength training apart

The immediate effect of a Boston brace on lung volumes and pulmonary compliance in mild adolescent idiopathic scoliosis

Idiopathic scoliosis (IS) is known to result in lung volume and pulmonary compliance reduction. Boston brace treatment of IS is an additional factor causing restrictive respiratory syndrome due to external chest wall compression. Nevertheless, the immediate effect of Boston bracing on the pulmonary compliance of scoliotic patients has not been studied systematically. Spirometric and plethysmographic lung volumes, static lung compliance (C-ST(L)) and specific lung compliance (C-ST(L)/functional residual capacity) of 15 scoliotic adolescents (14 females and 1 male, of mean age 14. 1 +/- 1.67 years, with mean Cobb angle 24.1 degrees +/- 7.88 degrees) were recorded twice, in a random sequence: once without the Boston brace (nBB) and once immediately after wearing the brace (BB). Our findings showed that bracing reduced vital capacity, residual volume, functional residual capacity (FRC), total lung capacity, and forced expiratory volume in 1 s in a proportional and significant way (P &lt; 0.001). C-ST(L) was also significantly reduced (P &lt; 0.001), but C-ST(L)/FRC remained unaltered. All BE and nBB indices were highly correlated. We concluded that Boston bracing in IS patients results in an immediate, predictable, and uniform reduction of lung volumes and pulmonary compliance. The reduction of C-ST(L), under bracing conditions was I elated to the decrease of lung volume; the C-ST(L)/FRC remained unaltered

Linear and nonlinear analysis of pressure and flow during mechanical ventilation

Objective: Linear modeling as a method of exploring respiratory mechanics during mechanical ventilation, was compared to nonlinear modeling for now dependence of resistance in three distinct groups of patients, those with: (a) normal respiratory function (NRF), (b) chronic obstructive pulmonary disease (COPD), or (c) adult respiratory distress syndrome (ARDS). Design and patients: Airways opening pressure (Pao), flow (V’), and volume (V) signals were recorded in 32 ICU mechanically ventilated patients, under sedation and muscle relaxation (10 NRF, 11 COPD, 11 ARDS). All patients were ventilated with controlled mandatory ventilation mode at three levels of end-expiratory pressure (PEEPe): 0, 5, and 10 hPa. Data were analyzed according to: (a) Pao = PE + Ers V + Rrs V’ and (b) Pao = PE + Ers V + k(1)V’ + k(2)’’: where Ers and Rrs represent the intubated respiratory system (RS) elastance and resistance, k(1) and k(2) the linear and the nonlinear RS resistive coefficients, and PE the end-expiratory pressure. The model’s goodness of fit to the data was evaluated by the root mean square difference of predicted minus measured Pao values. Results: NRF data fit both models well at all PEEPe levels. ARDS and particularly COPD data fit the nonlinear model better. Values of k(2) were often negative in COPD and ARDS groups, and they increased in parallel with PEEPe. A gradual increase in PEEPe resulted in better fit of ARDS and COPD data to both models. Conclusions: The model of V’ dependence of resistance is more suitable for the ARDS and particularly the COPD groups. PEEP tends to diminish the V’ dependence of respiratory resistance during the respiratory cycle, particularly in the COPD group, probably through an indirect effect of the increased lung volume