A pulse that is forceful and then suddenly collapses. It is usually found in patients with aortic regurgitation, a condition caused by a leaky aortic valve. The left ventricle of the heart ejects blood under high pressure into the aorta. Then the aortic valve normally shuts tight so that blood cannot return to the ventricle. If, however, the aortic valve cannot close completely, the blood in the aorta comes sloshing back into the ventricle, and the pressure and the pulse collapse. Also known as water-hammer pulse.
- Pulse, water hammer
A jerky pulse that is full and then collapses because of aortic insufficiency (when blood ejected into the aorta regurgitates back through the aortic valve into the left ventricle). This type of pulse was likened to a water hammer, a Victorian toy consisting of a glass tube filled partly with water or mercury in a […]
A machine that does the work both of the heart (pump blood) and the lungs (oxygenate the blood). Used, for example, in open heart surgery. Blood returning to the heart is diverted through the machine before returning it to the arterial circulation. Also called a heart-lung machine. John H. Gibson invented the heart-lung machine which […]
- Punch biopsy
A biopsy that is performed by using a punch, an instrument for cutting and removing a disk of tissue. For example, a punch biopsy of the skin may be done to make a diagnosis of skin cancer.
- Puncture wound
An injury that is caused by a pointed object that pierces or penetrates the skin. Puncture wounds carry a danger of tetanus.
- Puncture, lumbar
A procedure in which cerebrospinal fluid is removed from the spinal canal for diagnostic testing or treatment. Abbreviated LP. The patient usually lies sideways for the procedure, although LPs in infants are often done upright. After local anesthesia is i