Heart rate oscillates in synchrony with respiration. Several methods have been employed to assess this 'sinus arrhythmia', as an index of autonomic nervous system function. This paper proposes a new, easily computed measure, R, which is relatively resistant to the major nonrespiratory sources of variation, including premature beats, heart-rate differences among subjects, and slow trends in heart rate over time within subjects. The method can also be used more generally in any context where individuals are associated with event processes (for example, with seizures), when one requires assessment of the extent to which a point process is periodic with a particular known period.

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Lung-protective ventilation with a low tidal volume, plateau pressure < 30 cm H(2)O. oxygen saturation > 90% and permissive hypercapnia results in reduction of the mortality rate in patients with acute lung injury (ALI) and acute respiratory distress syndrome (ARDS). The level of the positive end-expiratory pressure (PEEP) must be chosen in relation to oxygen requirement. High frequency oscillatory ventilation and neurally adjusted ventilatory assist are promising methods. However, further studies with firm end-points have to be awaited before a final judgment is possible. Veno-venous extracorporeal membrane oxygenation (ECMO) can ensure life-sustaining gas exchange in patients with severe vitally compromised pulmonary failure, to provide time for lung tissue to heal and reduce ventilatory stress. The latest guidelines for analgesia and sedation in intensive care medicine demand consistent monitoring of the level of sedation and the intensity of pain. The sedation should be interrupted daily, with phases of awakenings and, if possible, spontaneous breathing. Methods of supportive treatment: Positional treatment (prone position) and inhalation of vasodilators can improve ventilation/perfusion mismatch and thus oxygenation. However, administration of surfactant is currently not advised in adult respiratory failure.