| ventilation/perfusion lung imaging | <radiology> See: ventilation agents, perfusion agents, Biello-Siegel criteria (12 Dec 1998) |
|---|---|
| ventilation/perfusion mismatch | An imbalance between alveolar ventilation and pulmonary capillary blood flow. (05 Mar 2000) |
| ventilation/perfusion ratio | The ratio of alveolar ventilation to simultaneous alveolar capillary blood flow in any part of the lung; because both ventilation and perfusion are expressed per unit volume of tissue and per unit time, which cancel, the units become liters of gas per liter of blood. (05 Mar 2000) |
| ventilator | A ventilator is a machine which mechanically assists patients in the exchange of oxygen and carbon dioxide (sometimes referred to as artificial respiration). (12 Dec 1998) |
| ventilator weaning | Techniques for effecting the transition of the respiratory-failure patient from mechanical ventilation to spontaneous ventilation, while meeting the criteria that tidal volume be above a given threshold (greater than 5 ml/kg), respiratory frequency be below a given count (less than 30 breaths/min), and oxygen partial pressure be above a given threshold (pao2 greater than 50mm hg). Weaning studies focus on finding methods to monitor and predict the outcome of mechanical ventilator weaning as well as finding ventilatory support techniques which will facilitate successful weaning. Present methods include intermittent mandatory ventilation, intermittent positive pressure ventilation, and mandatory minute volume ventilation. (12 Dec 1998) |
| ventilators, mechanical | Mechanical devices used to produce or assist pulmonary ventilation. (12 Dec 1998) |
| ventilators, negative-pressure | Body ventilators that assist ventilation by applying intermittent subatmospheric pressure around the thorax, abdomen, or airway and periodically expand the chest wall and inflate the lungs. They are relatively simple to operate and do not require tracheostomy. These devices include the tank ventilators ("iron lung"), portalung, pneumowrap, and chest cuirass ("tortoise shell"). (12 Dec 1998) |
| ventilatory compliance | The sum of dynamic compliance of the lung and thoracic compliance. (05 Mar 2000) |
| ventplant | An endo-osseous implant, usually made of titanium, utilised to provide support and fixation for a dental prosthesis by means of projections through the mucosa; also used to designate a family of implants. (05 Mar 2000) |
| ventrad | <anatomy> Toward the ventral side; on the ventral side; ventrally; opposed to dorsad. Origin: L. Venter belly + ad to. Source: Websters Dictionary (01 Mar 1998) |
| ventral | 1. Pertaining to the belly or to any venter. 2. Denoting a position more toward the belly surface than some other object of reference, same as anterior in human anatomy. Origin: L. Ventralis (18 Nov 1997) |
| ventral anterior nucleus of thalamus | The most rostral of the subdivisions of the ventral nucleus, receiving projections from the globus pallidus and projecting to the premotor and frontal cortex. Synonym: nucleus ventralis anterior thalami. (05 Mar 2000) |
| ventral aortas | The paired vessels ventral to the pharynx, which give rise to the aortic arches. (05 Mar 2000) |
| ventral border | The ventral or most forward margin of a structure. Synonym: anterior margin, ventral border. (05 Mar 2000) |
| ventral branch | Rami ventralis See: ventral primary rami of cervical spinal nerves, ventral primary rami of lumbar spinal nerves, ventral primary rami of sacral spinal nerves, ventral primary ramus of spinal nerve. (05 Mar 2000) |