β-blocker - Bite Block

β-blocker Beta blocker, beta-adrenergic blocking agent, β-adrenergic blocking agent See Beta blockers

Babington/hydrosphere nebulizer a type of nebulizer where a thin film of water flowed over a hollow glass sphere that had a slit in it through which a high-flow gas stream was passed creating a high-density aerosol.

Babinski's reflex dorsiflexion of the big toe with extension and fanning of the other toes elicited by firmly stroking the lateral aspect of the sole of the foot

back pressure a reduction in the pressure gradient secondary to down-flow resistance. This results in false high-flow and low-pressure readings.

back pressure compensation any method that allows for reading of accurate pressures and flows.

backup rate a control rate set on a ventilator to take over should a patient's assisted ventilations fall below the desired rate.

backward heart failure heart failure arising from accumulation of blood in the heart and increased filling pressures.

bacteremia the presence of bacteria in the blood

bacteria filter a device designed to remove particles and bacteria from the system. Usually rated in pore size or in microns.

bactericidal destructive to bacteria  

bacteriostatic tending to restrain bacterial growth

bacteriuria the presence of bacteria in the urine.

baffle a surface in a nebulizer designed specifically to cause impaction of large aerosol particles, causing either further fragmentation or removal from the suspension via condensation back into the reservoir

baffling the process of removing large water particles from suspension in a jet nebulizer so that the particles entering the patient's airways are of a uniform therapeutic size

bagassosis a self-limited lung disease caused by an allergic response to bagasse, the fungi-laden, dusty debris left after the syrup has been extracted from sugar cane

BAL abbreviation; see bronchoalveolar lavage

balloon angioplasty the insertion of a balloon-tipped catheter into the occluded or narrowed coronary artery to reopen the artery by inflating the balloon, fracturing the atheromatous plaque, and dilating the arterial lumen. This procedure, also called percutaneous trans luminal coronary angioplasty (PTCA), is often followed by insertion of a coronary artery stent.

barbiturate anyone of a group of organic compounds derived from barbituric acid, which have the capacity to cause depression of the central nervous system; examples include Amy tal, phenobarbitol, and sodium pentothal

barium a pale, soft, alkaline metallic element; a radiopaque barium (barium sulfate) compound commonly used in radiographic studies of the gastrointestinal tract

baroreceptor one of the pressure-sensitive nerve endings in the walls of the atria of the heart, the vena cava, the aortic arch, and the carotid sinus

barotrauma injury to the lungs caused by alveolar overdistention, often due to a high intraalveolar pressure, such as may occur during positive pressure ventilation; results in pneumothorax, pneumomediastinum, and subcutaneous emphysema; in hyperbaric medicine, an all-inclusive term used to describe injury to the body and breakage of equipment due to pressure changes.

barrel chest chest configuration in which the individual's anterior-posterior chest is equal to the lateral diameter.

basal at the bottom; alkaline.

basal metabolic rate (BMR) amount of energy required to maintain the most basic bodily functions, expressed as kilocalories per day and having a fixed relationship with gender, weight, height, and age.

base solution that yields a hydroxide ion (OH-) in an aqueous solution; species accepting the proton in a proton-transfer reaction.

base excess (BE) the difference between the normal buffer base (NBB) and the actual buffer base (BB) in a whole blood sample, expressed in mEq/L; a normal BE is + 2 mEq/L

baseline the part of the ECG during which electrical activity of the heart is absent. Commonly the interval between the end of the T wave and the onset of the -P wave (the TP segment) is considered the baseline and is used as the reference for the measurement of the amplitude of the ECG waves and complexes.

base of the heart the upper part of the heart formed by the right and left atria.

basic life support (BLS) primary patient assessment/treatment procedure to be taken to stabilize the emergency patient, including preliminary first actions such as assessing unresponsiveness and conducting the primary ABCD survey.

basophil a type of white blood cell that has a granular nucleus stained with basic dyes. These cells represent 1 percent or less of the total white blood cell count.

battery (legal) an unconsented actual touching that causes injury

Battle's sign bogginess of the temporal region of the head that may indicate fracture at the base of the skull

BCG vaccine an active immunizing agent against tuberculosis prepared from Bacille Calmette-Guerin benevolent deception actions in which the truth is withheld from the patient for his or her own good beneficence the principle that requires that health providers go beyond doing no harm and actively contribute to the health and well being of their patients benign not malignant or recurrent; characterized by mild symptoms or effect

Beer-Lambert law law defining the relationship between the concentration of a substance and the amount of light transmitted through it.

bellows accumulator a device used to store a volume of gas that will be pressurized for delivery to the patient or as a power source. Usually baglike in appearance.

bellows chamber the inside of a bellows containing a volume of gas.

bellows potentiometer a mechanism that senses the volume displacement of a bellows and releases the contents at a preset value, usually through an electrical signal.

benchmarking process of peer comparison that includes all efforts to determine not the average utilization of a particular diagnosis but the most medically appropriate utilization per diagnosis. This process is foundational to the standardization of health care delivery and the maximization of its benefits.

benign tumor noncancerous tumor.

Bennett Cascade a specialized heated passover humidifier employing a water-air froth as a humidifying technique.

Bennett MA-I ventilator a mechanical volume ventilator (Mechanical Assistor-l) until recently manufactured by the Puritan-Bennett Corp.

Bernoulli principle "First Law of Fluid Dynamics" used in 1738 by David Bernoulli to describe the relationship of fluid flow through a tube and to thus explain the pressure drop when fluid passes through a constriction in a rigid tube by showing how potential energy, kinetic energy, and pressure energy interact.

β-receptor adrenergic component of receptor tissue that, when activated, causes various physiologic reactions such as relaxation of the bronchial muscles and an increase in the rate and force of cardiac contraction.

beta blockers a group of drugs that block sympathetic activity; used primarily to treat tachyarrhythmias, hypertension, angina, and acute MI. Atenalol, esmolol, and metoprolol.

bicarbonate buffer system system influenced by the independent and direct effect of Pco2 on [HC03 -]; made up of two components-hydration of CO2 into carbonic acid (H2C03) and the dissociation of carbonic acid into HC03 - and hydrogen ion: H20 + CO2 ~ H2C03 ~ H + + HC03-·

bicuspid valve the bicuspid valve is situated between the left atrium and the left ventricle and is the only valve with two rather than three cusps. The bicuspid valve allows blood to flow from the left atrium into the left ventricle but prevents blood from flowing back into the atrium. Ventricular contractions in systole forces the blood against the valve, closing the two cusps and assuring the flow of blood from the ventricle into the aorta. Also called the mitral valve.

bidirectional ventricular tachycardia ventricular tachycardia characterized by two distinctly different forms of QRS complexes alternating with each other, indicating the presence of two ventricular ectopic pacemakers.

bifurcation a separation into two branches; the point of forking.

bigeminy an arrhythmia in which every other beat is a premature contraction. The premature beat may be atrial, junctional, or ventricular in origin (i.e., atrial bigeminy, junctional bigeminy, ventricular bigeminy).

bilevel positive airway pressure a term used to describe noninvasive positive pressure ventilation in which the inspiratory positive airway pressure (IPAP) is set greater than the expiratory positive airway pressure (EPAP).

bi-level continuous positive airway pressure (BiPAP) a variant of continuous positive airway pressure in which both inspiratory and expiratory pressures are set by the operator.

bilirubin breakdown product of hemoglobin that is metabolized in the liver.

bilirubinemia the presence of bilirubin in the blood

bilirubinuria the presence of bilirubin (a yellow or orange tinged pigment in the bile) in the urine

biological death present when irreversible brain damage has occurred, usually within 10 minutes after cardiac arrest, if untreated.

biopsy removal of a small piece of living tissue from an organ or other part of the body for microscopic examination to confirm or establish a diagnosis, estimate prognosis, or follow the course of a disease.

biotrauma inflammation of the lungs in response to inappropriate mechanical ventilation that promotes alveolar overdistension in inspiration and derecruitment on exhalation

Biot's respirations pattern of breathing symptomatic of elevated intracranial pressure and meningitis; characterized by short burst of uniform, deep respirations followed by period of apnea lasting 10 to 30 seconds.

BiPAP abbreviation for bi-Level positive airway pressure biphasic consisting of two phases

biphasic deflection a deflection having both a positive and a negative component (e.g., a biphasic P wave, a biphasic T wave).

bipolar limb leads leads I, II, and III.

bite block device that is placed between the teeth to prevent the patient from biting an orotracheal airway or from biting the tongue or lips, causing bleeding and trauma to the mouth; also used during bronchoscopy.

Black Pigment-Bursts

black pigment the material that gives damaged human lungs a black and sooty appearance.

bland aerosol inspired gas consisting of water, saline solution, or other substances without important pharmacologic action; used primarily to humidify, liquefy, or otherwise change the character of thick sections.

blebs and bullae localized destruction of portions of the lungs that may compress otherwise useful lung tissues.

bleeding diathesis a tendency toward abnormally inadequate blood clotting and an increase in bleeding.

blinding research technique for ensuring that the investigators and/or the participants are as aware as possible of the treatment being studied to avoid any tendency to prefer a specific outcome (bias).

block delay or failure of conduction of an electrical impulse through the electrical conduction system because of tissue damage or increased parasympathetic (vagal) tone.

blocked PAC a P' wave not followed by a QRS complex. Blood thinner A term used to indicate an anticoagulant, such as warfarin, used to reduce the prothrombin activity, thus inhibiting clot formation.

blood-brain barrier an anatomic-physiological feature of the brain thought to consist of walls of capillaries in the central nervous system and surrounding astrocytic glial membranes. The barrier separates the parenchyma of the central nervous system from blood. The blood-brain barrier prevents or slows the passage of some drugs and other chemical compounds, radioactive ions, and disease-causing organisms such as viruses from the blood into the central nervous system

blood gas the partial pressure values for gases dissolved in the blood. Most often measured are partial pressures of oxygen and carbon dioxide. Though not partial pressure values, the values for pH, bicarbonate ion concentration, and base excess are often also reported with blood gas results.

blood urea nitrogen (BUN) most common non-protein nitrogenous compound in the blood; measurement used to assess renal function; in the adult, normal values for BUN are between 7 and 21 mg/dL.

blow-by on-demand system a weaning system that provides a high-volume gas flow in response to patient inspiratory effort.

blunt chest trauma injury characterized by a direct bruise of the lung resulting in alveolar hemorrhage and edema; most often associated with automobile accidents. 

board certified holding certification in a medical specialty; usually obtained by passing one or more examinations offered by a specialty society or credentialing agency

Board of Directors (BOD) one of several governance and advisory entities of the AARC, composed of an executive committee consisting of the president, president-elect, immediate past president, vice president, treasurer, secretary, immediate past speaker of the House of Delegates, and chairperson of the Board of Medical Advisors.

Board of Medical Advisors one of several governance and advisory entities of the AARC; consists of four AARC sponsoring professional medical societies (the American Society for Anesthesia [ASA], the American College of Chest Physicians [ACCP], the American Thoracic Society [ATS], and the Society of Critical Care Medicine [SCCM]) that provide significant input concerning the art and science of the profession of respiratory care; provides medical guidance in the art and science of respiratory care through service to the AARC.

body humidity the absolute humidity in a volume of gas saturated at a body temperature of 37° C; equivalent to 43.8 mg/L

body plethysmography diagnostic tool that is used to achieve measurements of airway resistance (Raw), airway conductance (Gaw), and static lung volumes; based on Boyle's law. In practice, the patient is placed inside a fixed­volume, air-sealed body box where the effects of excursion of the chest wall can be measured by small pressure changes in the box and airway.

Bohr effect the relationship between hydrogen ion concentration and hemoglobin affinity for oxygen. An increase in hydrogen ion concentration decreases the affinity of hemoglobin for oxygen.

boiling point temperature required to raise the vapor pressure of a solution to atmospheric pressure; a colligative property of a solution.

Borg Scale of Perceived Exertion numeric scale for assessing dyspnea, from 0 representing no dyspnea to 10 as maximal dyspnea.

bolus a single large dose of a drug that provides an initial high therapeutic blood level of the drug.

BOMA abbreviation for the Board of Medical Advisors, the medical advisory group for the American Association for Respiratory Care

bore the internal diameter of a tube

Borg dyspnea scale a validated scale used by patients to quantify the severity of their dyspnea

botulism rare disorder caused by toxin produced by Clostridium botulinum, often ingested by improperly cooked food, wound contamination by the organisms, or absorption of the toxin from the gastrointestinal tract, particularly in infants; GI symptoms predominate initially, followed by neurologic impairment.

Bourdon gauge flowmeter flow control device with a fixed outlet orifice that allows an adjustable inlet pressure.

Boyle's law observation credited to Robert Boyle, early in the 18th century, that predicts the relation of a volume of a fixed mass of gas to a pressure change.

BPF abbreviation for bronchopleural fistula brachial of or pertaining to the arm

BPM (breaths per minute) respiratory rate usually a digital or analog indicator on the ventilator control panel.

body tank respirator iron lung a type of negative-pressure ventilator.

boiling point the temperature at which a liquid begins to turn to a gas. For water 100° Celsius, 212° Fahrenheit, 373° Absolute.

Bourdon gauge a device that indicates pressure measurements by use of a hollow coiled tube that attempts to straighten in response to increased pressure.

Bourdon regulator a regulator that incorporates a Bourdon gauge.

brachiocephalic trunk the short branch of the aortic arch giving rise to the right common carotid and right subclavian arteries; also called the innominate artery

brachytherapy radiotherapy treatment that involves applying an ionizing radiation source near the body area being treated; in respiratory treatment, this usually entails the endobronchial placement of encapsulated radionuclide in close proximity to an endobronchial malignancy.

bradycardia slowness of the heart (less than 60 beats/min).

bradycardias arrhythmias with rates of less than 60 per minute (e.g., sinus bradycardia; sinus arrest and sinoatrial [SA) exit block; junctional escape rhythm; ventricular escape rhythm; second-degree, type I AV block [Wenckebach]; second-degree, type II AV block; second-degree, 2:1 and advanced AV block; and third-degree AV block).

bradykinin a nonpeptide produced by activation of the kinin system in a variety of inflammatory conditions. It is an extremely potent vasodilator; it also increases vascular permeability, stimulates pain receptors, and causes contraction of a variety of extravascular smooth muscles.

bradypnea breathing rate slower than 12 breaths per minute.

breach of contract failure, without legal excuse, to carry out the terms of a legal agreement

breach of duty failure to complete an assignment that is legal and agreed upon

breathing exercises a broad category of physical activities designed to increase the strength and endurance of the respiratory muscles and to promote their more efficient use

bretylium tosylate an antiarrhythmic once used in the treatment of premature ventricular contractions (PVC's), ventricular fibrillation, and ventricular tachycardia.

Briggs adapter a T -shaped airway connector that has a straight body with a 22 mm OD breathing circuit connection at each end and a 15 mm patient connection that is perpendicular to the center of the body of the adapter.

bronchi larger air passages of the lungs.

bronchial artery embolization (BAE) method used to occlude or restrict blood flow within the bronchial artery; the therapy of choice when bleeding is from the bronchiectatic airways.

bronchial breath sounds auscultation sounds normally heard over the trachea, at the manubrium anteriorly and between the scapulae posteriorly; heard over the periphery of the lungs, this suggests consolidation of lung tissue.

bronchial challenge testing use of either methacholine or histamine to measure responsiveness to general stimuli, usually administered in a pulmonary function lab and followed (usually within 15 minutes) with a short-acting, β-agonist that results in a 12% to 15% increase in a patient's forced expiratory volume in 1 second (FEV1).

bronchial circulation regular or circuitous movement of the blood through the lungs; provides nutritional support for the lungs.

bronchiectasis an abnormal condition of the bronchial tree characterized by irreversible dilatation and destruction of the bronchial walls

bronchioles branching airways beginning 5 to 14 divisions below the segmental bronchi; usually 2 mm in diameter or less

bronchiolitis an acute infection of the lower respiratory tract causing expiratory wheezing, respiratory distress, inflammation, and obstruction of the bronchioles; bronchiolitis is usually caused by the respiratory syncytial virus (RSV) and is most common in infants under 2 years of age

bronchiolitis obliterans organizing pneumonia (BOOP) acute interstitial lung disease that appears to be a response of the lung to a variety of injuries affecting the smaller airways and alveoli as a unit (including infections, exposures to toxic gases, radiation therapy, drug toxicity, eosinophilic pneumonia, Wegener's granulomatosis, and hypersensitivity pneumonitis).

bronchitis an acute or chronic inflammation of the mucous membranes of the tracheobronchial tree

bronchoalveolar lavage (BAL) irrigation of bronchoalveolar specimen, used in the diagnosis of ventilator­associated pneumonia.

bronchoconstriction narrowing of the bronchi due to contraction of their smooth muscle bronchodilation the reversal of bronchoconstriction, usually via sympathetic stimulation

bronchodilation relaxation of the smooth muscles of the airways.

bronchodilator substance, especially a drug, that relaxes contractions of the smooth muscle of the bronchioles to improve ventilation to the lungs.

bronchogenic carcinoma a malignant lung tumor that originates in the bronchi.

bronchophony auscultation sound typical in consolidation of lung tissue, meaning that the normally aerated tissue has been filled with fluid, mucus, pus, or cellular debris; in bronchophony, the patient's repetition of "99" becomes easily audible, as opposed to its normal muffling.

bronchopleural fistula any air communication from the lung to the pleural space

bronchopneumonia an acute inflammation of the lungs and bronchioles, characterized by chills, fever, high pulse and respiratory rates, bronchial breathing, cough with purulent bloody sputum, severe chest pain, and abdominal extension

bronchopulmonary dysplasia chronic iatrogenic lung disease caused by oxygen toxicity and barotrauma resulting from positive pressure ventilation; incidence is greater in premature infants, perhaps related to the increased requirement for oxygen therapy and mechanical ventilation in this patient population.

bronchorrhea the excessive discharge of respiratory tract secretions

bronchoscopic washing technique designed to sample the airway, rather than the alveolar space, particularly in cytologic sampling when a patient has an exophytic lesion obstructing a lobar or segmental orifice.

bronchoscopy examination using a bronchoscope that enables inspection of the interior of the tracheobronchial tree and related diagnostic and therapeutic maneuvers, including taking specimens for culture, biopsy, and removal of foreign bodies.

bronchospasm involuntary sudden movement or convulsive contraction of the muscular coats of the bronchus.

bronchovesicular breath sounds sharing the characteristics of those heard over the trachea (bronchial sounds) and those arising from the more distal alveolar region (vesicular sounds)

Brownian diffusion a primary mechanism for deposition of inhaled particles less than 3 mm in diameter into the lung parenchyma

Brownian movement the random movement of molecules/ particles caused by being struck by other molecules/ particles.

bruit an abnormal sound heard on auscultation of the heart or large vessels, caused by turbulence or obstruction

BTPS indicates that a volume of gas is at body temperature (37°C), ambient (room) pressure, and 100% saturated with water vapor.

bubble humidifier system in which dry gas is directed toward the bottom of a water-filled reservoir, where the stream of gas is broken into bubbles that gain humidity as they rise through the water.

buccal of or pertaining to the inside of the cheek or the gum next to the cheek

buffer substances that maintain a relatively constant pH level when strong acids or strong bases are added.

buffer base the total blood buffer capable of binding hydrogen ions. Normal buffer base (NBB) ranges from 48 to 52 mEq/L

buffer system a chemical solution consisting of a weak acid and its salt, which has the ability to minimize changes in pH when adding acid or alkali

bulk flow a process involving the net movement of all the molecules within a fluid or gas system. Movement is caused by an "upstream" to "downstream" (high-to-low) pressure difference within the fluid or gas system that affects all of the molecules equally. This causes the net movement of all the molecules in the fluid or gas to be toward the same direction at the same time (e.g., water molecules flowing together down a stream).

bullae air space enlargements greater than 1 cm; can progressively enlarge and compress adjacent lung tissue, impairing respiratory function.

bullectomy removal of giant bullae (airspace enlargements that occupy one-third of a hemithorax), a reversible cause of pulmonary decompensation, particularly in patients with emphysema.

BUN abbreviation for blood urea nitrogen, a major by­product of protein metabolism that normally is excreted by the kidneys

bundle branch block (BBB) defective conduction of electrical impulses through the right or left bundle branch from the bundle of His to the Purkinje network, causing a right or left bundle branch block. It may be complete or incomplete (partial) or permanent (chronic) or intermittent (transient). It may be present with or without an intact interventricular septum.

bundle branches the part of the electrical conduction system in the ventricles consisting of the right and left bundle branches that conducts the electrical impulses from the bundle of His to the Purkinje network of the myocardium.

Bundle of His the part of the electrical conduction system located in the upper part of the interventricular septum that conducts the electrical impulses from the AV node to the right and left bundle branches. The bundle of His and the AV node form the AV junction.

bursts (or salvos) refers to the occurrence of two or more consecutive premature atrial, junctional, or ventricular contractions.