The Valsalva manoeuvre: physiology and clinical examples.

The Valsalva manoeuvre (VM), a forced expiratory effort against a closed airway, has a wide range of applications in several medical disciplines, including diagnosing heart problems or autonomic nervous system deficiencies. The changes of the intrathoracic and intra-abdominal pressure associated with the manoeuvre result in a complex cardiovascular response with a concomitant action of several regulatory mechanisms. As the main aim of the reflex mechanisms is to control the arterial blood pressure (BP), their action is based primarily on signals from baroreceptors, although they also reflect the activity of pulmonary stretch receptors and, to a lower degree, chemoreceptors, with different mechanisms acting either in synergism or in antagonism depending on the phase of the manoeuvre. A variety of abnormal responses to the VM can be seen in patients with different conditions. Based on the arterial BP and heart rate changes during and after the manoeuvre several dysfunctions can be hence diagnosed or confirmed. The nature of the cardiovascular response to the manoeuvre depends, however, not only on the shape of the cardiovascular system and the autonomic function of the given patient, but also on a number of technical factors related to the execution of the manoeuvre including the duration and level of strain, the body position or breathing pattern. This review of the literature provides a comprehensive analysis of the physiology and pathophysiology of the VM and an overview of its applications. A number of clinical examples of normal and abnormal haemodynamic response to the manoeuvre have been also provided.