Medical Glossary

halothane

A nonflammable inhalation anesthetic that produces general anesthesia; used along with analgesics and muscle relaxants for many types of surgical procedures.

harmonic scalpel

A surgical tool that uses ultrasound waves to cut tissue and seal bleeding vessels at the same time.

heart-lung machine

A medical device used in open heart surgery to support the body during the surgical procedure while the heart is stopped. It is also referred to as a "cardiopulmonary bypass pump" as it is used during cardiopulmonary bypass surgery.

The heart-lung machine consists of a chamber that receives the blood from the body, which is normally the responsibility of the heart€™s right atrium. This chamber temporarily holds the blood before it is diverted to oxygenater and pumped back throughout the body.

Technicians monitor the heart-lung machine carefully during surgery for changes in blood temperature, oxygen content, and the pump pressure. The temperature of the chamber containing the blood will slowly be raised near the end of surgery to restore the normal human body heat to the patient.

hematology

The diagnosis, treatment, and prevention of diseases of the blood and bone marrow as well as of the immunologic, hemostatic (blood clotting) and vascular systems. Because of the nature of blood, the science of hematology profoundly affects the understanding of many diseases.

hemostasis

A complex process which causes the bleeding process to stop. Most times this includes the changing of blood from a fluid to a solid state.

holter monitor

A portable, wearable EKG device which is worn by patient (usually for a period of 24-48 hours) to continuously monitor heart rhythms. The use of this device is especially effective in the diagnosis of rhythm problems, atrial fibrillation, angina, and other transient symptoms (those abnormalities which only appear sporadically and may not appear during a resting ECG)