Biomedical Instrumentation

Archive for May, 2009

Dear all! In order to describe and analyze behavior accurately, data must be recorded in terms other than the subjective report of an observer. Especially for a mathematical analysis, numerical values must be assigned to some aspects of behavior. For behavior involving motor response and motor skills, special testing devices have been developed to obtain a numerical rating. Other test required the completion of some manual or mental task in which the time required for completion is measured.

Sometimes the number of errors is also used to compare the performance of individuals. Many basic behavioral experiments are performed with animals as subject .These experiments are made in neutral environment provided by a sound proof enclosure, often called a skinner box in which the animal is isolated from the uncontrolled environmental stimuli. Each experiment must be designed in such a way that the behavior is well defined and can be measured automatically. In specially instrumented cages, the activity of animals can be quantified. Behavior emitted by organisms to interact with and modify their environment is called instrumental behavior.

Such behavior, which is controlled by central nervous system rather than by the automatic nervous system, can also be conditioned but in a way that differs from classical conditioning. Operant behavior that is positively reinforced tents to occur more frequently in the future but the behavior that is negatively reinforced decreases in frequency. In animal experiments, positive reinforcement is usually administered in the form of food or water given to animals that had been deprived of these commodities. This reinforcement can be administered easily by automatic dispensing devices.

Negative enforcement is in the form of harmless, but painful, electric shocks administered through isolated grids bars that serve as the floor of the cage. With suitable reinforcement, the animal can be conditioned to emit certain behavior such as pressing of bar, in response to a certain stimulus. From changes in the behavior that can occur under the influences of drugs, or when the stimulus is modified, valuable insight into the mechanisms of behavior can be obtained. My dear friends! I am sure this article will enhance your knowledge regarding instrumentation for the experimental analysis of behavior.

Dear friends! When a patient is incapable of adequate by natural process, mechanical assistance must be provided so that sufficient oxygen is delivered to the organs and tissues of the body and excessive levels of carbon-di-oxide or not permitted to accumulate. The procedure and instrumentation involved in providing mechanical assistance in respiration and in supplying hypoxic patients with higher-than-normal concentration of oxygen or therapeutic gases or medications constitute a field known as respiratory therapy. Until the past few years this field was known as inhalation therapy, but since it covers much more than inhalation, the more encompassing term is preferred. Instruments for respiratory therapy include such devices as inhalators, ventilators, respirators, resuscitators, positive-pressure breathing apparatus, humidifiers, and nebulizers. Many of these instruments, however, have overlapping functions, and the name used for a particular device may vary among manufactures.

Inhalators: The term inhalator generally indicates a device use to supply oxygen is some other therapeutic gas to a patient who is able to breathe spontaneously without assistance. As a rule, inhalators are used when concentration of oxygen higher than that of air is required. The inhalators consist of a source of therapeutic gas, equipment for reducing the pressure and controlling the flow of gas, and a device for administrating the gas. Devices for administrating oxygen to the patients include nasal cannulae and catheters, face masks that covers the nose and the mouth, and, in certain settings, such as pediatrics, oxygen tents. The oxygen concentration presented to the patient is controlled by adjusting the flow of gas into the mask.

Ventilators: The term ventilators and respirators are used interchangeably to describe equipment that may be employed continuously or inter mitten to improve ventilations of lungs and to supply humidity or aerosol medications to the pulmonary tree. Most ventilators in clinical settings use positive pressure during inhalation to inflate lungs with various gases or mixtures of gases. Expiration is usually passive, although under certain conditions pressures may be applied during the expiratory phase as well, in order to improve arterial oxygen tension only under rare circumstances is negative airway pressure utilized during expiration. My dear friends! I am sure this article will enhance your knowledge regarding respiratory therapy and hope, it is very useful.