Robledo Leal Condessa

Inspiratory muscle training did not accelerate weaning from mechanical ventilation but did improve tidal volume and maximal respiratory pressures: a randomised trial.

QUESTION Does inspiratory muscle training accelerate weaning from mechanical ventilation? Does it improve respiratory muscle strength, tidal volume, and the rapid shallow breathing index? DESIGN Randomised trial with concealed allocation and intention-to-treat analysis. PARTICIPANTS 92 patients receiving pressure support ventilation were included in the study and followed up until extubation, tracheostomy, or death. INTERVENTION The experimental group received usual care and inspiratory muscle training using a threshold device, with a load of 40% of their maximal inspiratory pressure with a regimen of 5 sets of 10 breaths, twice a day, 7 days a week. The control group received usual care only. OUTCOME MEASURES The primary outcome was the duration of the weaning period. The secondary outcomes were the changes in respiratory muscle strength, tidal volume, and the rapid shallow breathing index. RESULTS Although the weaning period was a mean of 8 hours shorter in the experimental group, this difference was not statistically significant (95% CI -16 to 32). Maximal inspiratory and expiratory pressures increased in the experimental group and decreased in the control group, with significant mean differences of 10cmH2O (95% CI 5 to 15) and 8cmH2O (95% CI 2 to 13), respectively. The tidal volume also increased in the experimental group and decreased in the control group (mean difference 72 ml, 95% CI 17 to 128). The rapid shallow breathing index did not differ significantly between the groups. CONCLUSION Inspiratory muscle training did not shorten the weaning period significantly but it increased respiratory muscle strength and tidal volume.

Blood markers of oxidative stress predict weaning failure from mechanical ventilation

Patients undergoing mechanical ventilation (MV) often experience respiratory muscle dysfunction, which complicates the weaning process. There is no simple means to predict or diagnose respiratory muscle dysfunction because diagnosis depends on measurements in muscle diaphragmatic fibre. As oxidative stress is a key mechanism contributing to MV‐induced respiratory muscle dysfunction, the aim of this study was to determine if differences in blood measures of oxidative stress in patients who had success and failure in a spontaneous breathing trial (SBT) could be used to predict the outcome of MV. This was a prospective analysis of MV‐dependent patients (≥72 hrs; n = 34) undergoing a standard weaning protocol. Clinical, laboratory and oxidative stress analyses were performed. Measurements were made on blood samples taken at three time‐points: immediately before the trial, 30 min. into the trial in weaning success (WS) patients, or immediately before return to MV in weaning failure (WF) patients, and 6 hrs after the trial. We found that blood measures of oxidative stress distinguished patients who would experience WF from patients who would experience WS. Before SBT, WF patients presented higher oxidative damage in lipids and higher antioxidant levels and decreased nitric oxide concentrations. The observed differences in measures between WF and WS patients persisted throughout and after the weaning trial. In conclusion, WF may be predicted based on higher malondialdehyde, higher vitamin C and lower nitric oxide concentration in plasma.

Pressão expiratória positiva na via aérea por máscara facial na hemodinâmica de pós-operatórios cardíacos

BACKGROUND [Corrected] Expiratory positive airway pressure (EPAP) is used in after cardiac surgeries. However, its hemodynamic effects have not been clearly studied. OBJECTIVE To evaluate the hemodynamic changes caused by EPAP in patients after cardiac surgery monitored by Swan-Ganz. METHODS Patients at the first or second cardiac surgery postoperative period hemodynamically stable with a Swan-Ganz catheter were included in the study. They were assessed at rest and after using 10 cmH2O EPAP at random. The variables studied were: oxygen saturation, heart rate and respiratory rate, mean artery pressures and pulmonary artery mean pressures (MAP and PAMP), central venous pressure (CVP) and pulmonary capillary wedge pressure (PAOP), cardiac output and index, and systemic and pulmonary vascular resistances. Patients were divided into subgroups (with ejection fraction <; 50% or > 50%) and data were compared by t test and ANOVA. RESULTS Twenty-eight patients were studied (22 men, aged 68 ± 11 years). Comparing the period of rest versus EPAP, the changes observed were: PAOP (11.9 ± 3.8 to 17.1 ± 4.9 mmHg, p < 0.001), PVC (8.7 ± 4.1 to 10.9 ± 4.3 mmHg, p = 0.014), PAMP (21.5 ± 4.2 to 26.5 ± 5.8 mmHg, p < 0.001), MAP (76 ± 10 for 80 ± 10 mmHg, p = 0.035). The other variables showed no significant differences. CONCLUSION EPAP was well tolerated by patients and the hemodynamic changes found showed an increase in pressure measurements of right and left ventricular filling, as well as mean arterial pressure.FUNDAMENTOS: A pressao expiratoria positiva na via aerea por mascara facial (EPAP) e utilizada no pos-operatorio de cirurgias cardiacas, entretanto, seus efeitos hemodinâmicos nao foram claramente estudados. OBJETIVO: Avaliar as alteracoes hemodinâmicas causadas pela EPAP em pacientes pos-cirurgia cardiaca monitorados por cateter de Swan-Ganz. METODOS: Foram incluidos no estudo, pacientes no primeiro ou segundo pos-operatorio de cirurgia cardiaca, estaveis hemodinamicamente e com cateter de Swan-Ganz. Eles foram avaliados em repouso e apos o uso de 10 cmH2O de EPAP, de forma randomizada. As variaveis estudadas foram: saturacao de oxigenio, frequencias cardiaca e respiratoria, pressoes arteriais medias sistemica e pulmonar (PAM e PAMP), pressoes venosa central (PVC) e de oclusao da ateria pulmonar (POAP), debito e indice cardiacos, e resistencias vasculares sistemica e pulmonar. Os pacientes foram divididos em subgrupos (com fracao de ejecao 50%) e os dados foram comparados por teste t e ANOVA. RESULTADOS: Vinte e oito pacientes foram estudados (22 homens, idade media 68 ± 11 anos). Comparando o periodo de repouso versus EPAP, as alteracoes observadas foram: POAP (11,9 ± 3,8 para 17,1 ± 4,9 mmHg, p < 0,001); PVC (8,7 ± 4,1 para 10,9 ± 4,3 mmHg, p = 0,014); PAMP (21,5 ± 4,2 para 26,5 ± 5,8 mmHg, p < 0,001); PAM (76 ± 10 para 80 ± 10 mmHg, p = 0,035). As demais variaveis nao mostraram diferencas significativas. CONCLUSAO: A EPAP foi bem tolerada nos pacientes e as alteracoes hemodinâmicas encontradas mostraram aumento nas medidas de pressao de enchimento ventricular direito e esquerdo, assim como, na pressao arterial media.

Increasing pressure support does not enhance secretion clearance if applied during manual chest wall vibration in intubated patients: a randomised trial

QUESTIONS What is the effect of increasing pressure support during the application of manual chest wall compression with vibrations for secretion clearance in intubated patients in intensive care? DESIGN A randomised trial with concealed allocation, assessor blinding and intention-to-treat analysis. PARTICIPANTS 66 patients receiving mechanical ventilation for greater than 48 hours. INTERVENTION All participants were positioned supine in bed with the backrest elevated 30 degrees. The experimental group received manual chest wall compression with vibrations during which their pressure support ventilation was increased by 10 cm H(2)O over its existing level. The control group received manual chest wall compression with vibrations but no adjustment of the ventilator settings. Both groups then received airway suction. OUTCOME MEASURES The primary outcome was the weight of the aspirate. Secondary outcomes were pulmonary and haemodynamic measures and oxygenation. RESULTS Although both treatments increased the weight of the aspirate compared to baseline, the addition of increased pressure support during manual chest wall compression with vibrations did not significantly increase the clearance of secretions, mean between-group difference in weight of the aspirate 0.4 g, 95% CI -0.5 to 1.4. Although several other measures also improved in one or both groups with treatment, there were no significant differences between the groups for any of the secondary outcomes. CONCLUSION Although increasing pressure support has previously been shown to increase secretion clearance in intubated patients, the current study did not show any benefits when it was added to chest wall compression with vibrations. TRIAL REGISTRATION NCT01155648.

Good practices for prone positioning at the bedside: Construction of a care protocol

Last year, interest in prone positioning to treat acute respiratory distress syndrome (ARDS) resurfaced with the demonstration of a reduction in mortality by a large randomized clinical trial. Reports in the literature suggest that the incidence of adverse events is significantly reduced with a team trained and experienced in the process. The objective of this review is to revisit the current evidence in the literature, discuss and propose the construction of a protocol of care for these patients. A search was performed on the main electronic databases: Medline, Lilacs and Cochrane Library. Prone positioning is increasingly used in daily practice, with properly trained staff and a well established care protocol are essencial.