Effects of continuous positive airway pressure on diaphragmatic kinetics and breathing pattern in healthy individuals.

BACKGROUND AND OBJECTIVE: In this study, we investigate the changes in diaphragmatic kinetics, breathing pattern and work of breathing induced by 10 cmH2 O of continuous positive airway pressure (CPAP). METHODS: We used sonography to study diaphragmatic kinetics and measured energy expenditure using indirect calorimetry in 50 healthy volunteers at 0 cmH2 O positive end expiratory pressure (ZEEP) and after application of 10 cmH2 O CPAP. In a subgroup of 14 subjects, the changes in thoracic and abdominal volumes and thoraco-abdominal asynchrony were recorded with inductive plethysmography, while accessory respiratory muscle activity was recorded with electromyography. RESULTS: Continuous positive airway pressure breathing induced acute lung hyperinflation of 600 mL above passive functional residual capacity. This hyperinflation induced changes in diaphragmatic kinetics and breathing pattern; diaphragmatic excursion, thickness and thickness ratio, tidal volume (Vt) and oxygen consumption (VO2) increased while respiratory rate decreased. The increase in Vt with CPAP was mainly due to rib cage contribution. Activation of the accessory inspiratory (scalene) and expiratory (transversus abdominis) muscles was recorded. The raised respiratory muscles workload induced an increase in VO2. CONCLUSION: In healthy volunteers, CPAP therapy leads to lung overdistention and recruitment of respiratory muscles. These mechanisms operate at a high energy cost.

Noise levels in Greek hospitals.

UNLABELLED: High noise levels have been recognized as a serious problem in hospital environments during both night- and daytime, and have been associated with a negative impact on patients' health status. The aim of this study was to measure and detect differences in noise levels between an ICU and a pulmonary ward in two general hospitals in Greece. METHODS: Noise measurements were recorded in one-hour intervals using the Cirrus CR: 245/R2 Environmental Noise Analyzer in a 30-bed pulmonary ward and in a 16-bed general ICU for seven consecutive days. RESULTS: Noise levels detected in the ward were significantly lower than those detected in the ICU (52.6 +/- 8.2 dB vs 59 +/- 2.2 dB, P Conclusion: Noise levels measured in the ward and in the ICU were high, significantly exceeding the highest permitted values for hospitals. The latter was more obviously recorded in the ICU.

Recombinant human erythropoietin therapy in critically ill patients: a dose-response study [ISRCTN48523317].

INTRODUCTION: The aim of this study was to assess the efficacy of two dosing schedules of recombinant human erythropoietin (rHuEPO) in increasing haematocrit (Hct) and haemoglobin (Hb) and reducing exposure to allogeneic red blood cell (RBC) transfusion in critically ill patients. METHOD: This was a prospective, randomized, multicentre trial. A total of 13 intensive care units participated, and a total of 148 patients who met eligibility criteria were enrolled. Patients were randomly assigned to receive intravenous iron saccharate alone (control group), intravenous iron saccharate and subcutaneous rHuEPO 40,000 units once per week (group A), or intravenous iron saccharate and subcutaneous rHuEPO 40,000 units three times per week (group B). rHuEPO was given for a minimum of 2 weeks or until discharge from the intensive care unit or death. The maximum duration of therapy was 3 weeks. RESULTS: The cumulative number of RBC units transfused, the average numbers of RBC units transfused per patient and per transfused patient, the average volume of RBCs transfused per day, and the percentage of transfused patients were significantly higher in the control group than in groups A and B. No significant difference was observed between group A and B. The mean increases in Hct and Hb from baseline to final measurement were significantly greater in group B than in the control group. The mean increase in Hct was significantly greater in group B than in group A. The mean increase in Hct in group A was significantly greater than that in control individuals, whereas the mean increase in Hb did not differ significantly between the control group and group A. CONCLUSION: Administration of rHuEPO to critically ill patients significantly reduced the need for RBC transfusion. The magnitude of the reduction did not differ between the two dosing schedules, although there was a dose response for Hct and Hb to rHuEPO in these patients.