| positive-negative pressure breathing | Inflation of the lungs with positive pressure and deflation with negative pressure by an automatic ventilator. (05 Mar 2000) |
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| positive-pressure respiration | A method of mechanical ventilation in which pressure is maintained to increase the volume of gas remaining in the lungs at the end of expiration, thus reducing the shunting of blood through the lungs and improving gas exchange. (12 Dec 1998) |
| positive-pressure respiration, intrinsic | Non-therapeutic positive end-expiratory pressure occurring frequently in patients with severe airway obstruction. It can appear with or without the administration of external positive end-expiratory pressure (positive-pressure respiration). It presents an important load on the inspiratory muscles which are operating at a mechanical disadvantage due to hyperinflation. Auto-peep may cause profound hypotension that should be treated by intravascular volume expansion, increasing the time for expiration, and/or changing from assist mode to intermittent mandatory ventilation mode. (12 Dec 1998) |
| critical pressure | The minimum pressure required to liquefy a gas at the critical temperature. (05 Mar 2000) |
| postoperative pressure alopecia | Loss of hair over a circumscribed area usually on the posterior scalp, resulting from continuous pressure on the occiput in a lengthy operative procedure, or unconsciousness following a drug overdose. (05 Mar 2000) |
| pressure | 1. The act of pressing, or the condition of being pressed; compression; a squeezing; a crushing; as, a pressure of the hand. 2. A contrasting force or impulse of any kind; as, the pressure of poverty; the pressure of taxes; the pressure of motives on the mind; the pressure of civilization. "Where the pressure of danger was not felt." (Macaulay) 3. Affliction; distress; grievance. "My people's pressures are grievous." (Eikon Basilike) "In the midst of his great troubles and pressures." (Atterbury) 4. Urgency; as, the pressure of business. 5. Impression; stamp; character impressed. "All saws of books, all forms, all pressures past." (Shak) 6. <mechanics> The action of a force against some obstacle or opposing force; a force in the nature of a thrust, distributed over a surface, often estimated with reference to the upon a unit's area. Atmospheric pressure, Center of pressure, etc. See Atmospheric, Center, etc. <engineering> Back pressure, pressure which resists the motion of the piston, as the pressure of exhaust steam which does not find free outlet. Fluid pressure, pressure like that exerted by a fluid. It is a thrust which is normal and equally intense in all directions around a point. Pressure gauge, a gauge for indicating fluid pressure; a manometer. Origin: OF, fr. L. Pressura, fr. Premere. Source: Websters Dictionary (01 Mar 1998) |
| pressure alopecia | Loss of hair over a circumscribed area usually on the posterior scalp, resulting from the continuous pressure on the occiput in a lengthy operative procedure, or unconsciousness following a drug overdose. (05 Mar 2000) |
| pressure amaurosis | A loss of vision occurring a few seconds after intraocular pressure exceeds systolic pressure of retinal arteries. (05 Mar 2000) |
| pressure anaesthesia | Loss of sensation produced by pressure applied to a nerve. Synonym: compression anaesthesia. (05 Mar 2000) |
| pressure atrophy | The wasting of hard or soft tissue resulting from excessive pressure applied to tissue by a denture base. (05 Mar 2000) |
| pressure collapse | Pulmonary collapse due to external compression of the lung, as by a pleural effusion or pneumothorax. (05 Mar 2000) |
| pressure-controlled respirator | A respirator that provides a predetermined pressure to gases during inhalation, the volume of gas moved being variable, depending upon resistance. (05 Mar 2000) |
| pressure dressing | A dressing by which pressure is exerted on the area covered to prevent the collection of fluids in the underlying tissues; most commonly used after skin grafting and in the treatment of burns. (05 Mar 2000) |
| pressure epiphysis | A secondary centre of ossification in the articular end of a long bone. (05 Mar 2000) |
| pressure gangrene | <dermatology> A chronic ulcer that appears in pressure areas in debilitated patients confined to bed or otherwise immobilised, due to a circulatory defect from the enhanced tissue pressure in high-contact areas, often occurring over a bony prominence (for example sacral decubitus). (27 Sep 1997) |