Rabbit Ears Pattern-Respiratory Insufficiency

rabbit ears pattern see rSR' pattern.

raccoon eyes dark discoloration (bruising) around the eyes; a sign of possible basilar skull fracture

racemic a mixture of two complementary stereo isomers, or racemates, that makes it optically inactive under polarized light.

radiation therapy primary treatment of the intrathoracic tumor or for metastatic disease, involving the use of x-rays or gamma rays to slow or stop the proliferation of malignant cells.

radioaerosol an aerosol with particles that have been labeled with a radioactive isotope; used to assist researchers in analyzing pulmonary aerosol deposition and clearance

radiographic opacity property of an object in an x-ray image that proves it to be neither transparent nor translucent.

radioimmunoassay a test that measures minute amounts of antibodies or antigens by the use of radioactive substances

radiolucent pertaining to a substance or tissue that readily permits the passage of x-rays or other radiant energy; compare with radiopaque

radionuclide angiocardiography noninvasive technique for evaluating left ventricular function, using intravenous injection of a radioisotope (most commonly technetium­99m) and the use of a gamma-ray scintillation camera to detect the isotope's signal within the left ventricle.

radiopaque of or pertaining to a substance or tissue that does not readily permit the passage of x-rays or other radiant energy; compare with radiolucent  

rale discontinuous types of lung sounds heard on auscultation of the chest, usually during inspiration; the term crackle is now preferred

Raman spectroscopy method used to measure CO2 in capnographs.

ramp study a cardiopulmonary stress test in which there is a gradual, continuous increase in the subject's workload throughout the test. This increase in workload continues up to the maximum level tolerated by the subject. A ramp study differs from a progressive graded test in which workload levels are increased in a series of stages (steps) and a workload level is maintained for a short period of time before there is an increase to the next workload level.

rapid shallow breathing index (RSBI) or (f/VT) the patient's spontaneous respiratory rate (f) in breaths per minute divided by the spontaneous tidal volume in liters. Values above 100 are associated with poor weaning outcomes

rate control a device that allows selection of the number of breaths per minute.

rate conversion table a table converting the number of small squares between two adjacent R waves into the heart rate per minute.

rate frequency of occurrence stated in incidents per unit of time; for example, 16 per minute.

rate of change amount of change in a function's dependent variable for a given change in the independent variable.

rate of impulse formation (the firing rate) see Slope of phase-4 depolarization.

ratio light a visual warning indicating that the I:E ratio is not within predetermined limits.

Raynaud's phenomenon a temporary constriction of arterioles in the skin causing short episodes of numbness and color changes in the fingers and toes. This condition is usually idiopathic

R double prime (R") the third R wave in a QRS complex.

real gas gases that do not fit all of the kinetic theories.

real-time recordings test tracings that are produced directly and at the same time as the breathing maneuver is being performed by the subject.

rebreathe to inhale expired gas (high in carbon dioxide content)

rebreathed volume the volume of any breathing apparatus that results in previously expired gas being inhaled; equivalent to the mechanical deadspace

rebreathing mask a gas delivery system in which expired gases are oxygen enriched and inhaled again by the patient. Characterized by a reservoir bag and a series of one-way valves.

receptor chemical structure on the surface of a cell that combines with an antigen to produce a discrete immunologic component; also, a sensory nerve ending that responds to various kinds of stimulation.

"Reciprocal" ECG changes ECG changes of evolving acute myocardial infarction present in opposite ECG leads, being, for the most part, opposite in direction to those in the facing ECG leads (i.e., a mirror image). For example, an elevated ST segment and a symmetrically tall, peaked T wave in a facing ECG lead is mirrored as a depressed ST segment and a deeply inverted T wave in an opposite ECG lead.

reconditioning physical activity to strengthen essential muscle groups, improve overall oxygen use, and enhance the body's cardiovascular response to physical activity

recontamination the process by which articles previously contaminated and cleaned or sterilized become contaminated again

recruitment maneuver sustained inflation at high airway pressure that has been advocated as an adjunct to mechanical ventilation in patients with ARDS; the result of a recruitment maneuver is decreased atelectasis.

rectus abdominis abdominal muscle group that functions as an accessory muscle of ventilation

recurrent laryngeal nerves branches of vagus nerves that innervate the larynx

REDOX an acronym pertaining to any REDuction­OXidation chemical reaction

reducing valve a mechanism whose purpose is to decrease the delivery pressure of a gas to a lower "working" pressure.

REE abbreviation for resting energy expenditure; a measure of caloric outlays at rest  

reentry mechanism a mechanism by which an electrical impulse repeatedly exits and reenters an area of the heart causing one or more ectopic beats.

reexpansion pulmonary edema pulmonary edema that forms following rapid reexpansion of a lung that has been compressed with pleural fluid or pneumothorax  

reference electric potential a constant electrical voltage against which electrical flow in a sampling chamber is compared during gas analysis.

reference potentiometer a device that compares a predetermined-preset signal to other signals within an electrical or fluidic system.

referred pain pain occurring at a site distal to its origin

reflecting key skill used in critical thinking; involves the ability to "think about thinking" so as to explore assumptions, opinions, biases, and decisions; may be considered introspective or "inward think" or, if retrospective, "past think."

reflex an involuntary response to a stimulus.

reflux a backward flow

refractory inability to respond to a stimulus.  

refractory hypoxemia an abnormal deficiency of oxygen in the arterial blood that is resistant to treatment; usually indicates the presence of right-to-left shunting

refractory period the time during which a cell or fiber may or may not be depolarized by an electrical stimulus depending on the strength of the electrical impulse. It extends from phase 0 to the end of phase 3 and is divided into the absolute refractory period (ARP) and relative refractory period (RRP). The absolute refractory period extends from phase 0 to about midway through phase 3. The relative refractory period extends from about midway through phase 3 to the end of phase 3.

registered pulmonary function technologist (RPFT) individual previously certified in pulmonary function technology, who has gained appropriate education and/or experience and who has successfully passed the pulmonary function registry examination of the NBRC.

registered respiratory therapist (RRT) Respiratory therapist who has successfully passed the advanced-level exam of the NBRC.

regulator high-pressure reducing valve that is attached to the outlet of a cylinder of gas to reduce the pressure in the cylinder to the standard and safe working pressure of 50 psig.

rehabilitation the restoration of the individual to the fullest medical, mental, emotional, social, and vocational potential of which he/she is capable

rehabilitation (pulmonary) a multidisciplinary program designed to help stabilize or reverse both the physiopathology and psychopathology of pulmonary diseases and return patients to the highest possible functional capacity allowed

relative humidity the ratio of actual to potential water vapor in a volume of gas; that is, how much is present as opposed to how much could be present.

relative refractory period (RRP) of the ventricles the period of ventricular repolarization during which the ventricles can be stimulated to depolarize by an electrical impulse stronger than usual. It begins at about the peak of the T wave and ends with the end of the T wave.

REM sleep phase of the sleep cycle marked by the presence of rapid eye movements on electrooculography.

renal pertaining to the kidneys.

renal calculi kidney stones

renal dysplasia abnormal development of tissue in the kidneys.

ReoPro trade name for abciximab.

reperfusion therapy treatment to reopen an occluded atherosclerotic coronary artery using a thrombolytic agent or a mechanical means such as percutaneous coronary interventions that include percutaneous trans luminal coronary angioplasty (PTCA), coronary artery stenting, directional coronary atherectomy (DCA), and rotational atherectomy.

repolarization the electrical process by which a depolarized cell returns to its polarized, resting state.

repolarization wave the progression of the repolarization process through the atria and ventricles that appears on the ECG as the atrial and ventricular T waves.

repolarized state the condition of the cell when it has been completely repolarized.

resect to remove surgically

resection excision of a portion of an organ or other anatomic structure.

reservoir bag a pliable container that holds a volume of pre­mixed gas for use in succeeding ventilations or as a backup.

reservoir system a collection of bags or tubes that form a device for containing a supply of a gas or liquid for later use.

residual volume (RV) the volume of gas remaining in the lungs after a complete exhalation

res ipsa loquitur 'the thing speaks for itself;' rule of evidence whereby negligence of alleged wrongdoer may be inferred from the mere fact that the accident happened

resistance opposition to a force; ratio of pressure change to flow change; lung characteristic that, with compliance, serves as a determinant in the mechanics of air flow in and out of the lungs.

resistive load pressure necessary to overcome the flow resistance of the airways (including endotracheal tube) along with lung and chest wall tissue resistance.

resonance type of sound produced in percussion, which is loud, low, and long such as may be heard over normal lung tissue.

resorption atelectasis collapse of distal lung units due to mucus plugging of airways

respiration rate control the mechanism that controls the number of respirations per minute in a ventilator.

respirator a mask-like apparatus used to filter inspired air for breathing

respiratory acidosis abnormal increase in hydrogen ion concentration associated with an elevated Paco2.

respiratory alkalosis abnormal decrease in [H+] associated with reductions in Paco2.

respiratory alterans alternating between use of the diaphragm for short periods and use of the accessory muscles to breathe. It is indicative of end-stage respiratory muscle fatigue

respiratory bronchiolitis rare lung disorder that occurs exclusively in cigarette smokers; characterized by intracytoplasmic golden-brown, granular pigment within alveolar macrophages in respiratory and terminal bronchioles.

respiratory care protocol patient care plans initiated and implemented by respiratory therapists, one purpose being the standardization of decision making. Respiratory care protocols provide flexibility because clinicians can modify them according to the needs of the patient; also referred to as therapist-driven protocols (TDP's), patient-driven protocols (PDP's), or simply protocols.

respiratory distress syndrome condition of the newborn characterized by dyspnea with cyanosis; the most common cause for hypoxemic respiratory failure in premature neonates.

respiratory exchange ratio (RER) ratio of Vco2 to VO2 (Vco2/Vo2). During steady state exercise at moderate to low levels of exertion, the RER reflects the respiratory quotient (RQ), which is the ratio of Vco2 to VO2 in the mitochondria.

respiratory failure a condition in which the exchange of oxygen and/or carbon dioxide between the alveoli and the pulmonary capillaries is inadequate

Respiratory Index (RI) the ratio of the alveolar-arterial oxygen tension gradient to the arterial partial pressure of oxygen (P(A-a)o2/ Pao2); a measure of the efficiency of oxygen transfer across the lung

respiratory inductance plethysmography (RIP) method for indirectly measuring tidal volume; sensors use a circuit of coiled wire woven into an elastic band and excited by an AC current. Inductance results from alternating electrical currents creating magnetic fields around themselves and those changing magnetic fields altering other electrical currents that they encounter.

respiratory insufficiency a condition in which breathing is accompanied by abnormal signs or symptoms, such as dyspnea or paradoxical breathing

Respiratory Quotient-R Wave

respiratory quotient (RQ) the body's total exchange of oxygen for carbon dioxide, expressed as the ratio of the volume of carbon dioxide produced to the volume of oxygen consumed per unit of time at steady-state conditions. Depending on the net metabolic needs of all parts of the body at a given moment, the ratio ranges from 0.7 to 1 and averages around 0.8. The values of RQ change according to the fuel being metabolized; the RQ of fat is lower than that of glucose, whereas the RQ of protein is between that of glucose and fat

respiratory sinus rythm the natural cycle of arrhythmia that occurs through the influence of breathing on the flow of sympathetic and vagus impulses to the sinoatrial node. The rhythm of the heart is primarily under the control of the vagus nerve, which inhibits heart rate and the force of contraction. When we inhale, the vagus nerve activity is impeded and heart rate begins to increase. When we exhale this pattern is reversed. The degree of fluctuation in heart rate is also controlled significantly by regular impulses from the baroreceptors (pressure sensors) in the aorta and carotid arteries. When RSA is enhanced through biofeedback, the goal is usually to reinforce the natural feedback activity of the baroreceptors through our breathing pattern.  

respiratory therapist a graduate of a CAAHEP/CoARC accredited school designed to qualify the graduate for the registry examination of the National Board for Respiratory Care (NBRC)

respiratory therapy consult service a program in which respiratory care services are determined by respiratory care practitioners based on prescribed guidelines or algorithms, otherwise known as an evaluate-and-treat program

respirometer a device used to measure the volume of respired air or gas

respondeat superior 'let the master answer'; it means that the master is liable in certain cases for the wrongful acts of his servant; for example, a doctor may be liable for the wrongful acts of his assistant. The doctrine is inapplicable where injury occurs while the servant is acting outside the legitimate scope of authority

response time a measure (usually in msec) of the speed with which a mechanical ventilator can respond to a patient's inspiratory effort and cycle into the inspiratory phase

resting potential a difference in charge, or negative electrical potential, that exists between the inside and outside of a nerve or cardiac tissue cell in the resting state due to concentration differences of potassium and sodium ions across the cell membrane

resting membrane potential (RMP) the transmembrane voltage that exists when the heart muscle is at rest.

resting state of a cell the condition of a cell when a layer of positive ions surrounds the cell membrane and an equal number of negative ions lines the inside of the cell membrane directly opposite each positive ion. A cell in such a condition is called a polarized cell.  

restrictive lung disease a broad category of disorders with widely variable etiologies, but all resulting in a reduction in lung volumes, particularly the inspiratory and vital capacities; categorized according to origin; that is, skeletal/thoracic, neuromuscular, pleural, interstitial, and alveolar

resuscitation the restoration of life by artificial respiration and external chest compression.

Retavase trade name for reteplase (r-PA), a thrombolytic agent. Reteplase (r-PA) A thrombolytic agent that converts plasminogen, a plasma protein, to plasmin, which in turn dissolves the fibrin binding the platelets together within a thrombus (fibrinolysis), causing the thrombus to break apart (thrombolysis). Trade name: Retavase.

retention as applied to aerosol therapy, the proportion of particles deposited within the respiratory tract, either at a specific location or as a whole

reticuloendothelial refers to the system responsible for phagocytosis of cellular debris, pathogens, and foreign substances and for removing them from the circulation

retinopathy a noninflammatory eye disorder resulting from changes in the retinal blood vessels

retinopathy of prematurity formation of fibrous tissue behind the lens of the eye caused by excessive oxygen administration to premature infants; produces blindness in its worst form; also called retrolental fibroplasias.

retractions the sinking inward of the skin around the chest cage with each inspiratory effort

retrograde atrial depolarization abnormal depolarization of the atria that begins near the AV junction, producing a negative P' wave in Lead II. Typically associated with junctional arrhythmias.

retrograde AV block delay or failure of backward conduction through the AV junction into the atria of electrical impulses originating in the bundle of His or ventricles.  

retrograde conduction conduction of an electrical impulse in a direction opposite to normal (i.e., from the AV junction or ventricles [through the AV junction] to the atria or SA node). Same as retrograde AV conduction.

retrolental fibroplasia a formation of fibrous tissue behind the lens of the eye, resulting in blindness

retrospective studies studies that look back at records to study what has been done.

retrosternal behind the sternum

retrovirus a family of viruses that contains RNA (ribonucleic acid) and reverse transcriptase; some retroviruses are oncogenic and can induce tumors

Reynolds' number dimensionless number that describes factors associated with generation of laminar or turbulent flow such that units of measurement cancel each other when consistent units are used; the associated equation demonstrates that density and viscosity are independent factors affecting turbulence. On a qualitative basis, the Reynolds' number describes a ratio of inertial forces to viscous forces.

rheostat an electronic device that allows variable control of the amount of electrical current flowing from the device.

rheumatoid factor a macroglobulin type of antibody; increased levels are found in the blood of persons with rheumatoid arthritis

rhinitis inflammation of the mucous membranes of the nose, usually accompanied by swelling of the mucosa and a nasal discharge

rhinorrhea the free discharge of a thin nasal mucus

rhinovirus any of about 100 serologically distinct, small RNA viruses that cause about 40% of acute respiratory illnesses

rhonchi abnormal sounds heard on auscultation of a respiratory airway obstructed by thick secretions, muscular spasm, neoplasm, or external pressure

rhonchial fremitus an abnormal vibration felt on the chest wall as air passes through a narrowed airway

rhonchus deep, rumbling respiratory sound that is more pronounced in auscultation on expiration and is usually continuous, caused by air passing through an airway partially obstructed by thick secretions, spasm of the airways, or presence of a tumor; higher-pitched or sibilant rhonchi arise in smaller bronchi, whereas lower-pitched, sonorous or snoring rhonchi are more common with thick secretions in larger airways.

ribonucleic acid (RNA) nucleic acid in which the sugar component is ribose; acts as the machinery for this protein synthesis process by translating the genetic information stored in DNA into protein structures.

ribosome tiny cellular particle that provides a surface for protein synthesis and provides enzymes to catalyze the process.

Riemann sum one method for approximating a definite integral; also called the numerical integration formula; often used to approximate exhaled volume.

rigid bronchoscopy bronchoscopy using a nonflexible instrument, particularly useful in assessing patients with massive hemoptysis, removing aspirated foreign bodies (especially in children) and performing laser bronchoscopy or dilatation of tracheobronchial strictures or for retrieval of large volumes of tenacious secretions, necrotic debris, or large biopsy specimens.

right atrial enlargement (right atrial dilatation and hypertrophy) usually caused by increased pressure and/or volume in the right atrium. It is found in pulmonary valve stenosis, tricuspid valve stenosis and insufficiency (relatively rare), and pulmonary hypertension and right ventricular hypertrophy from various causes. These include chronic obstructive pulmonary disease (COPD), cor pulmonale, status asthmaticus, pulmonary embolism, pulmonary edema, mitral valve stenosis or insufficiency, and congenital heart disease.

right axis deviation (RAD) a QRS axis greater than +90°  Extreme right axis deviation-a QRS axis between -90° and ±180° (indeterminate axis).

right bundle branch (RBB) part of the electrical conduction system of the heart that conducts electrical impulses into the right ventricle.

right bundle branch block (RBBB) defective conduction of electrical impulses through the right bundle branch. It may be complete or incomplete and be present with or without an intact interventricular septum. Typical ECG patterns:

• rSR' pattern in lead V "the so-called "M" (or rabbit ears) pattern

• Tall "terminal" R waves in leads aVR and V1-V2

• Deep and slurred "terminal" S waves in leads I, aVL, and V5- V6

• qRS pattern in leads V5-V6-typical of right bundle branch block with an intact interventricular septum

• QSR pattern in leads V1-V2-typical of right bundle branch block without an intact interventricular septum

right heart failure inadequacy of the right ventricle to maintain the normal circulation of blood. This results in distended veins of the body, especially the jugular veins; body tissue edema; and congestion and distension of the liver and spleen. The lungs are typically clear.  

right precordial (or septal) leads leads V1-V2.

right-sided (unipolar) leads leads V2R, V3R,V4R, V5R and V6R; each obtained using a positive electrode attached to a specific area of the right anterior chest wall and a central ter­minal. The right-sided leads overlie the right ventricle. The positive electrode for each right precordial lead is attached as follows:

• V2R: Right side of the sternum in the fourth intercostal space

• V3R: Midway between V2R and V4R

• V4R: Right midclavicular line in the right fifth intercostal space

• V5R: Right anterior axillary line at the same level as V4R

• V6R: Right midaxillary line at the same level as V4R

right-to-left shunt an anatomical bypass in which blood flows from the venous to the arterial side of the circulation, bypassing the lungs. This lowers both the oxygen content and the P02 of the arterial blood

right ventricular hypertrophy (RVH) increase in the thickness of the right ventricular wall because of chronic increase in pressure and/or volume within the ventricle. It is found in pulmonary valve stenosis and other congenital heart defects (e.g., atrial and ventricular septal defects), tricuspid valve insufficiency (relatively rare), and pulmonary hypertension from various causes. These include chronic obstructive pulmonary disease (COPD), status asthmaticus, pulmonary embolism, pulmonary edema, and mitral valve stenosis or insufficiency.

right ventricular MI a myocardial infarction caused by the occlusion of the right coronary artery.

Ringer's lactate solution frequently used sterile IV solution containing sodium, potassium, calcium, and chloride ions in about the same concentrations as present in blood, in addition to lactate ions.

rise-time the rate of increase in a parameter; in ventilatory support, the rate at which airway pressure rises during early inspiration (a function of flow)

RNA ribonucleic acid; controls protein synthesis in cells and takes the place of DNA in some viruses

rocking bed unconventional ventilation device with action that has been compared to a piston in a cylinder. As the patient's head moves down, the piston-like viscera and diaphragm slide cephalad within the cylinder-like chest wall, assisting exhalation. In the foot-down position, the abdominal contents and diaphragm slide caudad, assisting inhalation.

roentgenography radiography; the making of film records of internal structures of the body by passage of x-rays or gamma rays through the body to act on specially sensitized film.

role fidelity the concept that practitioners in each specialty have a duty to understand the limits of their role and to practice with fidelity

R-on-T phenomenon an ominous type of premature ventricular contraction (PVC) that falls on the T wave of the preceding QRS-T complex. This can cause ventricular tachycardia or ventricular fibrillation.

ROS abbreviation for review of symptoms, a component of the medical history

rotary blower a type of fan or compressor in which a fanlike device spins at high speeds to produce a pressurized gas flow.

rotary-driven piston a piston that is connected to and whose stroke is governed by the movement and speed of a wheel like device.

rotary wheel see "rotary-driven piston."

rotary vane respirometer a volume recording device that measures the movement of a drumlike cylinder with blade or wing shaped extensions (air foils).

rotational atherectomy the use of a rotational, drill-like device to remove a calcified thrombus.

r-PA see Reteplase (r-PA).

RP' interval the section of the ECG between the onset of the QRS complex and the onset of the P' wave following it. This is present in junctional arrhythmias and occasionally in ventricular arrhythmias.

R prime (R') the second R wave in a QRS complex.

R-R interval the section of the ECG between the onset of one QRS complex and the onset of an adjacent QRS complex or between the peaks of two adjacent R waves.

RSA abbreviation for Respiratory Sinus Rythm

RS pattern refers to the appearance of a QRS complex in which there is an initial tall R wave followed by a deep S wave.

rSR' pattern a typical QRS complex pattern in VI present in right bundle branch block. Also referred to as the "M" or rabbit ears pattern.

RSV abbreviation for respiratory syncytial virus

Rule of nines formula for estimating the amount of body surface covered by bums by assigning 9% to the head and each arm, twice 9% (18%) to each leg and the anterior and posterior trunk, and 1 % to the perineum; modified in infants and children because of the different body proportions.

rule utilitarianism a moral reasoning approach based not on which act has the greatest utility but on which rule would promote the greatest good if it were generally followed

"R" valve a diaphragm-type valve used on the inlet portions of Mark II AMBU and Infant AMBU resuscitation bags.

R wave the positive wave or deflection in the QRS complex. An upper case "R" indicates a large R wave; a lower case "r," a small R wave. May be tall or small; narrow or wide, slurred, or notched.