Nursebob's MICU/CCU Survival Guide
Concepts in Critical Care

Abbreviations & Terms

A-a DO2 - alveolar–arterial oxygen gradient

A/C - assist–control ventilation

Acute Lung Injury – a precursor to ARDS, lesser level of injury, severe oxygenation abnormality presence of diffuse parenchymal infiltrates on chest x-ray (three or four quadrants), hypoxemia as manifested by a PaO2/FiO2 (fraction of inspired oxygen) ratio of <300 torr, and a pulmonary capillary wedge pressure of <18 mmHg, or no clinical evidence of elevated left-sided heart filling pressure.

AEP - acute eosinophilic pneumonia {see interstitial pneumonia(s)

Afterload - Any resistance against which the ventricles must pump in order to eject its volume is called afterload. The resistance to the ventricular ejection afterload. This central venous pressure (CVP) and right atrial pressure (RA) gives an indication of amount of blood returning to the right side of the heart. Vasodilation as a result of sepsis or hypothermia, low blood pressure, or the effective nitrates, will cause a decrease in afterload. On the other hand, vasoconstriction as a result of hypovolemia, hypothermia, aortic stenosis, hypertension or the affect of vasopressive agents may cause an increase in afterload.

AIP - acute interstitial pneumonia {(see interstitial pneumonia(s)

Air beda specially designed air–filled floating mattress bed designed to prevent development and/or alleviate and facilitate healing of bed sores and certain physical problems associated with long term restriction to bed, especially in a paralyzed and/or coma state.

Air leak syndromes – A spectrum of diseases with the same underlying pathophysiology. Air leaks involve overdistension of the alveolar sacs or terminal airways, leading to disruption of airway integrity and dissection of air into the surrounding spaces. The pulmonary air leak syndromes include pneumomediastinum, pneumothorax, pulmonary interstitial emphysema, and pneumopericardium.

Alveolar-arterial oxygen gradient (A-a DO2 ) – the difference between the amount of oxygen in the arterial blood and the amount of oxygen actually delivered to the lungs. Normally this value is less than 100 Hg but in the context of severe respiratory disease it may exceed 600 mm Hg.

ALI - acute lung injury

Alveolitis – inflammation of the alveoli.

Alveolus (sg.), Alveoli (pl.) – the tiny spherical air exchange sacs in the lung, located at the ends of your smallest airways (bronchiole). The alveoli are surrounded by capillaries (small blood vessels), which are the blood vessels bringing blood into interior of the lung that is depleted in oxygen. The exchange of oxygen and carbon dioxide takes place through a membrane separating the alveoli and capillaries. The alveoli are lined with and supported by tissue called the interstitium

Aplasia – incomplete development of tissue, absence of growth.

Aplastic – incapable of growing new tissue.

APRV - airway pressure release ventilation

ARDS - adult (or acute) respiratory distress syndrome. Adult or Acute Respiratory Distress Syndrome – same criteria as acute lung injury (ALI) except more profound severe oxygenation abnormality with a PaO2/FiO2 ratio of <200 torr.  The pathophysiology of ARDS is characterized by a cascading effect in a proinflammatory response by the body. 

ARF - acute respiratory failure

Arterial Blood Gas Test – the test that tells the health professional how your lungs are working. It is very sensitive to changes in breathing patterns and is used to establish treatment for your condition and qualify for home oxygen therapy.  The main function of the lung is to bring fresh oxygen to the body tissues and get rid of carbon dioxide.  The arterial oxygen and carbon dioxide pressure levels are measured in millimeters of mercury.  The percent of oxygen that is carried in the blood is also measured. The pH tells us if the blood has too much of the acid component (carbon dioxide) or too much base (bicarbonate).

Arterial oxygen tension (PaO2) – the partial pressure of arterial oxygen.

Aspiration – generally, the act of drawing in air/to breathe (inspiration); often more specifically means inhaling (inspiration) of stomach contents which have been projected back up through the esophagus and into the mouth and/or throat, or other foreign substances (smoke inhalation particulate matter). Aspiration is one of the three leading precipitating factors in ARDS cases.

Atelectasis – no air in the alveoli, lung solid.

Atonic – without tone; weak (atonia, atony, atonicity).

Bacteremia – the presence of bacteria in the blood.

Bacteriuria – the presence of bacteria in the urine (100,000 or more organisms per ml).

BAL - bronchoalveolar lavage

Barotrauma – The injury inflicted on lung tissue with the use of high pressures during ventilation.  But see, Volutrauma.

BALF - bronchoalveolar lavage fluid

BOOP - Bronchiolitis Obliterans Organizing Pneumonia (BOOP) – a chronic scarring and obstruction process involving the lung's small airways. It may become so diffuse, the entire airway may become filled with fibrotic scar tissue. When the small airways are destroyed, the larger airways become dilated and chronically inflamed. It may occur after a bout of pneumonia or with lung transplantation. 

Bronchitis – inflammation of the bronchi, may be primary or secondary (to some other precipitating cause(s), acute (short term) or chronic (long term).

BPD - bronchopleural dysplasia

BPF - bronchopleural fistula

Bronchitis – an obstructive lung disease where chronic airway inflammation is present with an abnormally large amount of secretions produced. A person will be diagnosed with chronic bronchitis if he or she coughs up secretions on most days for at least 3 months of the year; for at least 2 consecutive years. Because the secretions block the airways, it blocks oxygen from getting into your blood stream. The respiratory muscles have to work harder to get air in and out of the lungs.

Bronchi (pl.). {bronchus (sg.), bronchial (adj.)} – the two tubes into which the trachea divides at its lower end, branching into the lungs.

Bronchial tube – subdivisions of the bronchi after they enter the lungs.

Bronchiole {bronchiolar (adj.)} – one of the minute subdivisions of the bronchi which terminate in the alveoli or air sacs of the lungs.

Bronchiolitis {bronchiolitic (adj.)} – inflammation of the bronchioles, capillary bronchitis.

Bronchoalveolar lavage (BAL) – irrigation or washing out of the bronchi and alveoli, resulting in obtaining bronchalveolar lavage fluid (BALF) which assists in removing unwanted mediators, degradation byproducts, and perhaps defective surfactant and proteins substances from the surface and membrane linings (often before surfactant replacement), and the fluid obtained may be used in performing measurements to ascertain the levels of various mediators and substances as a diagnostic tool.

Bronchography {bronchographic (adj.)} – preparation of an X–ray after introduction of radio–opaque substance into the bronchial tree.

Bronchopleural fistula (BPF) – bronchopleural fistulas are large air leaks which develop secondary to collapsed lungs.

Bronchopulmonary – pertaining to the bronchi and the lungs.

Bronchorrhea – an excessive discharge of mucous from the bronchial mucous membrane.

Bronchoscopy – an examination of the internal lining of the bronchi via a type of endoscope called a bronchoscope, also used for removal of a foreign body and biopsy of tissue.

Bronchospirometer – an instrument for measuring the capacity of one lung.

Bronchotracheal – pertaining to the bronchi and trachea.

Bullae – are large air-containing spaces within the lungs caused by the destruction of walls of neighboring alveoli that emphysema causes. Once present, they are not very effective in the oxygen–carbon dioxide exchange.

CaO2 - concentration of oxygen in arterial blood

Carbon dioxide partial pressure (PaCO2) – the partial pressure of carbon dioxide in the arterial blood.


Cardiac Index (CI) - an adjustment of the cardiac output based on the size of the person’s body. It is the most and individualized cardiac parameter that the nurse can use. It is based on body surface area (BSA). The formula for calculating cardiac index is CI= CO/BSA. The normal value for this parameter is 2.5 to 4L/min/m2

Cardiac Output (CO) - can be calculated if we know the heart rate and the stroke volume.

CO=HR*SV dynes/Cm2 Normal 4-8 L/min

Poor ventricular filling such as may be found in hypovolemia can cause a decrease in cardiac output. It may be due to poor emptying and as a result of decrease myocardial contractility. This is usually found with a myocardial infarction, cardiac ischemia, arrhythmias, or papillary muscle dysfunction. It can also be found with vasodilatation as a result of vasopressors or sepsis. An increase in cardiac output may occur whenever there is an increase in oxygen demand, psychological stimulation, and a response to a systemic inflammation, hepatic disease, viral toxic doses, or neurogenic mediated vasodilation.

Central Venous Pressure (CVP) - a measurement of the pressure in the right atrium. This reflects the right ventricular diastolic pressure, or the ability of the right side of the heart to pump blood. This is a valuable tool for assessing the relationship between cardiac action, vascularity, and blood volume. However, keep in mind that the central venous pressure is not accurate for the measurement of left ventricular function and maybe the last parameter to change. The normal reading for central venous pressure is to 2-6 mm Hg.

CEP - chronic eosinophilic pneumonia {see interstitial pneumonia(s)}

Chronic Obstructive Pulmonary Disease (COPD) – this diagnosis is often used as a catch–all phrase to

include emphysema, chronic bronchitis and asthma. An individual may have only one component or a portion of all three states. 

CI see Cardiac Index

CMV - conventional mechanical ventilation

CO see Cardiac Output

CO2 - carbon dioxide

Compliance – A measure of the stiffness of the lung. A less compliant lung (stiffer) requires higher inspiratory pressures to maintain ventilation. Technically, compliance describes the elastic properties of the lung measured as change in volume divided by change in pressure. Thus, the greater the compliance the larger the delivered volume can be per unit of pressure. Lung compliance is measured in mL/cm of H2O.

Conation – one of the three aspects of the mind, in particular dealing with "willing and desiring", the others being cognition (awareness) and affection (feeling or emotion).  They may work as a whole, but any one may dominate any mental process.

Contractility - the ability of the cardiac muscle to contract

COPD see chronic obstructive pulmonary disease

Cor Pumonale – is defined as right sided heart failure. Blood is returned to the right side of the heart low in oxygen and is pumped up to the lungs to replenish the oxygen supply. In lung disease, there may be high pressure in the lungs, making it difficult to pump against. After time, the right ventricle of the heart may balloon out and become ineffective. The blood could back up in the system and swelling make be noted in the ankles.

CPAP - continuous positive airway pressure, constant (or continuous) positive airway pressure. Constant (or continuous) positive airway pressure (CPAP) – a non–invasive ventilation   assistance technique, lesser level than full mechanical ventilation; constant, low level pressure delivered to the lungs during spontaneous ventilation (i.e. off a ventilator), usually through a face mask or nasal prongs. CPAP is useful in mild lung diseases, sleep apnea, or during the end stages of recovery of more severe diseases. 

CVP see Central Venous Pressure

DIC - disseminated intravascular coagulation; see the What–Is–DIC? in the What–Is section for further discussion and information

DIP - desquamatic interstitial pneumonia {see interstitial pneumonia(s)}

DO2 - oxygen delivery

ECLS - extracorporeal (outside the body) life support; encompasses ECMO and ECCO2R

ECMO - extracorporeal (outside the body, heart–lung machine) membrane oxygenation

ECCO2R - extracorporeal (outside the body) CO2 removal

EF see Ejection Fraction

Ejection Fraction (EF) - a measurement of how well the left ventricle, or the heart's main pumping chamber, works. It is expressed as a percentage of blood that leaves the heart with each beat. Normally the left ventricle ejects 55 to 70 percent of the blood during each heartbeat. Generally, the lower the Ejection Fraction the more severe the symptoms.

EMDR - eye movement desensitization and reprocessing in the What–Is section

ERCP - endoscopic retrograde cholagio prancreatography; see What–Is–ERCP?

ET - endotracheal tube

FEV1 - forced expiratory volume in one second

FiO2 - fractional concentration of inspired oxygen

Flow control – mechanical ventilator control that regulates the rate at which air is passed through the lungs.

Flow Rate Values – speed at which air moves through the lung.

Forced Expiratory Volume in One Second (FEV1) – is a measurement of flow rate; this is the amount of air that can be exhaled in the first second after you take the deepest breath that you can. In obstructive lung disease, this measurement is as basic as taking your temperature. You should know what your FEV1 is on a normal day. Asthmatics who take their FEV1 with a peak flowmeter on a daily basis can tell when an attack is beginning before the person even feels symptoms.

Fraction of inspired oxygen (FiO2) – the percentage of oxygen in the air inhaled, either on or off the ventilator. FiO2 ranges are from 21% (e.g. in room air) to 100% (e.g. pure oxygen).

Functional residual capacity (FRC) – the volume of gas that remains in the lungs after the exhalation of a spontaneous or mechanically assisted breath. Infants with surfactant deficiency have a lower FRC.

Global Fear Syndrome – a mental state associated with a high level of generalized fear.

FRC - functional residual capacity

GIP - giant cell interstitial pneumonia {see interstitial pneumonia(s)

Hemodynamic Monitoring - There are both invasive and noninvasive techniques that can be used to determine the hemodynamic status of the patient. Taking a simple blood pressure with a cuff is a hemodynamic measurement. Hemodynamic monitoring can be much more involved than a simple blood pressure reading. It may involve actual measurements of pressures directly within the heart. That is, invasive homodynamic monitoring. By using invasive hemodynamic monitoring the nurse is able to evaluate the patient's immediate response to treatment such as drugs and mechanical support.

HFFI - high frequency flow interrupted (ventilation)

HFJV - high–frequency jet ventilation

HFOV - high frequency oscillatory ventilation

HFV - high–frequency ventilation

High frequency ventilation – the use of small tidal volumes at fast ventilatory rates (180-900 breaths per minute) to reduce the amount of damage that is associated with conventional ventilators that deliver larger tidal volumes at lower frequencies.

High-pressure ventilation – mechanical ventilation therapy that is administered at a high pressure and may cause lung damage.

Hypoxemia – diminished amount (reduced saturation) of oxygen in arterial blood (PaO2/FiO2 ratio less than 200 mm Hg); hypoxic hypoxemia–interference with pulmonary oxygenation; stagnant hypoxia–a reduction in blood flow, as seen in the finger nails in surgical shock or in cold weather.

ICU Psychosis – a psychotic state entered into by some ICU patients, perhaps as a  result of medication(s) used in the ICU or as a defense mechanism or other response to the trauma involved in the stressful ICU setting; often characterized by hallucinations, visual and/or auditory, and lack of ability to recognize reality.

I:E - inspiratory: expiratory ratio. Inspiratory to expiratory ratio (I:E ratio) – the ratio of the inspiratory to the expiratory times; normal I:E ratios are 1:1, 1:1.5, and 1:2.

IPF - interstitial or idiopathic pulmonary fibrosis

ILV - independent lung ventilation

IMV - intermittent mandatory ventilation

Inspiratory time – the time set between breaths on a mechanical ventilator. Inspiratory time is normally set between 0.3 and 0.6 seconds.

Interstitial pneumonia(s) – pneumonia centered in the interstitium, the tissue that lines and supports the alveoli.

iNO - inhaled nitric oxide

IP - interstitial pneumonia

IR - inverse ratio ventilation

IV - intravenous

IVH - intraventricular hemorrhage

IVOX - intravascular blood gas exchanger

LFPPV - low–frequency positive pressure ventilation

LIP - lymphocytic interstitial pneumonia {see interstitial pneumonia(s)}

MalvP - mean alveolar pressure

MAP see Mean airway pressure or Mean Arterial Pressure

Mean airway pressure (MAP or Paw) – the mathematical average of all the different pressures being used by the ventilator to support the infant. MAP is expressed in cm H2O. A level of 20 cm H2O indicates severe disease and a level of 10 cm H2O suggests that the neonate may be ready to be weaned from the ventilator.

Mean Arterial Pressure (MAP) -70-90 mm Hg

MMV - mandatory minute ventilation

MODS - multi–organ dysfunction; precedes MOF

MOF - multiple organ failure

MRSA - methicillin–resistant staphylococcus aureus infection in the What–Is section.

Multiple Organ Dysfunction Syndrome (MODS) – presence of altered organ function in an acutely ill patient such that homeostasis cannot be maintained without intervention.

Multiple Organ Failure (MOF) – the complete shutting down of multiple organs throughout the body.

Muscle atrophy – loss of muscle tissue, strength and structure resulting from non–usage.

NIP - non-specific interstitial pneumonia {see interstitial pneumonia(s)}

NO - nitric oxide (see articles on Nitric Oxide in Learn About ARDS Section 1)

O2 - oxygen

O2 Sat Level – oxygen saturation level in the blood

OAD - obstructive airways disease

OI - oxygen index

Oxygenation index (OI) – a frequently used calculation that incorporates FiO2, Paw, and PaO2. The OI is generally between 30-40 in the presence of severe respiratory distress. OI is calculated as follows:

 OI = FiO2 x Paw x 100

PA catheter - See Pulmonary Artery Catheter.

PAD see Pulmonary Artery Diastolic Pressure

PaO2 - Oxygen partial pressure (PO2) – refers to the pressure exerted by oxygen when dissolved in liquid.

PaCO2 - carbon dioxide partial pressure

PaO2 - partial pressure of oxygen

PAM see Pulmonary Artery Mean Pressure

PAP - peak airway pressure

Partial Liquid Ventilation – ventilation after filling the lungs with a liquid that has some unique properties; very low surface tension, similar to surfactant, a substance that is produced in the lungs and prevents the alveoli from collapsing and sticking together during exhalation. It also has a high density, oxygen readily diffuses through it, and it may have some anti-inflammatory properties.

PAS see Pulmonary Artery Systolic Pressure

Paw - airway pressure

PAWP see Pulmonary Artery Wedge Pressure (PACWP, Wedge)

PACWP see Pulmonary Artery Wedge Pressure (PAWP, Wedge)

PCIR - pressure–controlled inverse ratio ventilation

Peak inspiratory pressure (PIP) – the maximum pressure being used to inflate the neonate’s lungs during each mechanical breath.

PEEP - positive end–expiratory pressure

Permissive hypercapnia - method of ventilation where increased or elevated level of CO2 in the blood is permitted to exist.

PIE see Pulmonary interstitial emphysema

PIP - peak inspiratory pressure

Pmus - pressure generated by muscle contraction

Pneumothorax – leakage of air in the pleural cavity from the lungs.

Positive end expiratory pressure (PEEP) – the pressure that the ventilator maintains at the end of expiration to prevent atelectasis.

PP - positive pressure ventilation

Ppl - pleural pressure

Preload - Preload is the degree of muscle fiber stretching present in the ventricles right before systole. It could be looked at as the amount of blood available to be ejected at systole.

Pressure control – mechanical ventilator control (several types of pressure controls exist) which regulates the pressure of the air used for inflating the lungs.

PS - pressure support

PSV - pressure support ventilation

PT - physical therapy or pulmonary therapy (see article on Pulmonary Rehab in Learn About ARDS section 1)

PTSD - post traumatic stress disorder

Pulmonary Artery Catheter (PA catheter, Swan, Swan-Ganz) - The pulmonary artery catheter normally has four ports. The proximal port can be used to measure central venous pressure and as an injectate port during the measurement of cardiac output. There is a distal port which goes to the pulmonary artery and which is connected to the pressure line. A balloon port is also present where a 1.5-ml special syringe is connected. This is used during the determination of pulmonary artery wedge pressure. No more than 1.5 ml of air should ever be injected into a pulmonary artery catheter during wage determination. The pulmonary artery catheter has several functions. It allows for continuous bedside hemodynamic monitoring. So that vascular tone, myocardial contractility, and fluid balance can be assessed and managed. It measures pulmonary artery pressure, central venous pressure, and allows for hemodynamic calculations to be determined. Cardiac output can be determined using the thermodilution method. Transvenous pacing can be done. The administration of fluids is not recommended with a pulmonary artery catheter.

Pulmonary Artery Diastolic Pressure (PAD) - 6-12 mm Hg

Pulmonary Artery Mean Pressure (PAM) - 10-15 mm Hg

Pulmonary Artery Systolic Pressure (PAS) - 20-30 mm Hg

Pulmonary Artery Wedge Pressure (PAWP, PACWP, Wedge) - The balloon of the pulmonary artery catheter is inflated. As the pulmonary artery catheter makes its way into small capillary vessels and becomes wedged. The pulmonary artery wage pressures (PAWP) may be measured. Generally, this measurement is more important than the central venous pressure. If there is left ventricular dysfunctions, such as with a myocardial infarct or cardiomyopathy, a threat to tissue oxygenation and low cardiac output may exist. Left ventricular function may be assessed by using the pulmonary catheter wedge pressure, which would provide an indirect measurement of preload. With a normal stroke volume the wedge pressure should be for 4-12 mm Hg.

Pulmonary Fibrosis – a process whereby the lung muscle becomes stiff due to scarring (development of fibrous structures), rather than problems with the airways. You will not be able to expand your lung and the volume of air that you can hold will decrease.  Because scarring occurs, it acts as a barrier for the oxygen–carbon dioxide exchange. It is known as a restrictive lung disease, rather than obstructive. There are several causes as well as unknown reasons for its development; generally referred collectively as Interstitial Pulmonary Fibrosis (IPF).Many times the cause is unknown in which case it is called Idiopathic (from an unknown cause; idiopathic would not be used where the cause is known such as an underlying condition like ARDS) Pulmonary Fibrosis (also IPF), characterized by progressive shortness of breath, “crackles” in both lungs, and a chest x-ray that shows small linear opacities and “honeycombing” at the lung bases.  A biopsy usually shows UIP (usual interstitial pneumonia).  It could begin as a result of an industrial exposure, drugs used to fight cancer, after a bout of pneumonia or from allergic disorders.  See also interstitial pneumonia(s). 

Pulmonary hypertension – also called primary pulmonary hypertension, constriction of blood vessels in the lungs with consequent resistance to blood flow which increases pressure in the right ventricle and atrium of the heart.  Cause unknown.  Usually leads to death from congestive heart failure within 2 to 10 years after onset.

Pulmonary interstitial emphysema (PIE) – a form of emphysema caused by the build-up of air between the interstitial pulmonary tissues.

pulmonary vascular resistance (PVR) - is a reflection of right ventricular afterload. It is normally 40 to 220 dynes/second/cm2.

Pulse Oximeter – is a device that uses a light to estimate the oxygen saturation of your arterial blood. A sensor that looks like a clothespin is put on the person's finger and a light passes through from one side to the other. The percentage of oxygen and the person's pulse rate are displayed. If the main concern of treatment is to monitor oxygen levels, the pulse oximeter gives a percentage that is not as reliable as one determined by arterial blood gas, but helpful in determining approximate values. The values are dependent on the person's blood flow, and other factors that may affect readings. It doesn't hurt a bit and does not incur the laboratory costs.

Pursed Lip Breathing – one of the most effective tools people with COPD have to use. When a person breathes in through his or her nose, it helps to distribute the air more evenly in the lungs. Instead of passively exhaling, purse the lips, as if ready to kiss, and slowly breathe out. Exhale twice as long as it took to take the breath in. This helps push the air out of the damaged alveoli in emphysema and around the secretions that fill the airway of chronic bronchitis. Inhale for 2 seconds; exhale for 4 seconds; inhale for 3 seconds, exhale for 6 seconds and so on. Remember this technique when becoming short of breath. Many people are afraid to become short of breath and do anything to avoid it (that is, they simply do nothing).  The person is in control if he or she knows pursed lip breathing. A person might go up a flight a stairs a little to fast or walk too quickly to catch a bus. Instead of gasping, breathing in through the nose quickly, pucker up and blow out, again and again until breathing slows down and control is regained. It truly does work! (It will help if to pucker up and blow out as the leg is lifted to climb stairs!)

PV - pressure–volume

PVR see pulmonary vascular resistance

RAP see Right Atrial Pressure

Residual Volume (RV) – is the amount of air that can't be blown out after forceful exhalation. In obstructive diseases, as emphysema and asthma, this value may increase due to air trapped in the lung behind blocked airways. That is when the exchange of oxygen and carbon dioxide is hampered

Right Atrial Pressure (RAP) - 2-6 mm Hg

Right Ventricular Pressure (RV, RVP) - can only be measured if a pulmonary artery catheter (Swan-Ganz) has been inserted into the right atrium and the tip of the catheter is advanced and allowed to travel through the tricuspid valve with blood into the right ventricle. The normal pressures within the right ventricle should be between 20 to 30 mm Hg systolic and less than five mm Hg diastolic.

RV see residual volume or right ventricular pressure.

RVP see right ventricular pressure

SaO2 - oxygen percent saturation (arterial)

SI see Stroke Index

SIMV - synchronized intermittent mandatory ventilation

SIRS - systemic inflammatory response syndrome

Stroke Index (SI) -Stroke index (SI) like cardiac index (CI) is a more useful measure for determining hemodynamics that is based on the patient size. It can be calculated: SI=SV/BSA. Normally it is 40-50 ml/m2.

Stroke Volume (SV) - The volume of blood injected with each heartbeat is stroke volume. Whenever there is a condition with results in cardiac dysfunction stroke volume will eventually declined. This reduction in stroke volume might not be apparent initially. Therefore, it should be used in conjunction with additional hemodynamic parameters. Normally the stroke volume is 60 to 130 ml/beat ml. This parameter can be calculated by: SV=CO/HR Any parameter that affects stroke volume will also affect cardiac output. These include preload, after load, and contractility

SV see Stroke Volume

SVRI see Systemic Vascular Resistance Index

Swan, Swan-Ganz - See Pulmonary Artery Catheter.

Systemic Vascular Resistance - Systemic vascular resistance (SVR) can be calculated from the main arterial pressure (MAP), central venous pressure (CVP) and cardiac output (CO). SVR=MAP-CVP/CO*80 Normally 800-1200 dynes.

Systemic Vascular Resistance Index (SVRI) - 2000-2400 dynes

Ti - inspiratory time

Tidal Volume (Vt) – the amount of air breathed in and out each breath taken normally without even thinking about it (spontaneously) or via mechanical ventilation. In mechanical ventilation, the ventilator has a control setting to regulate tidal volume. Recent study data shows that a lower tidal volume is better.

Thoracotomy Decortication – surgical procedure to remove hardened or fibrotic lung tissue in order, hopefully, to expose underlying more pliant lung tissue to enable the lungs to inflate in an unrestricted or less restricted manner, facilitating easier breathing by the patient and proper functioning of the lungs.

Trachea – windpipe; the fibrocartilaginous tube lined with mucous membrane passing from the pharynx to the bronchi.

TLC - total lung capacity

Tracheotomy – fenestration - (cutting of window–like opening, a fenestra) into the anterior (front side) wall of the trachea by removal of a circular piece of cartilage from the third and fourth rings, for establishment of a safe airway (see endotracheal tube) and reduction of 'dead space.' This procedure is done usually when a long term or prolonged problem is expected to be present. Because it passes through the larynx, the person will not be able to speak unless the opening of the tube is covered. It is also important to maintain humidity to the airway, since the nose has been bypassed.

transducer -

UIP - usual interstitial pneumonia {see interstitial pneumonia(s)}

VC - vital capacity

Ventilation-perfusion mismatch (V:Q mismatch) – An imbalance between alveolar ventilation and pulmonary capillary blood flow.

Vital Capacity (VC) – the volume of the lung measured when a person maximally exhales after the deepest possible breath can be taken in. This represents 80% of the person's entire lung capacity – there is 20% that can't be exhaled or the lung would collapse. When the lung muscle becomes stiff, as in pulmonary fibrosis, the vital capacity will decrease due to the lung not being able to expand to get air in. It will also decrease in people who are obese, since the lung has to work harder to move the excess weight on the chest with every breath.

Volutrauma – The injury inflicted on lung tissue with the use of large tidal volumes during ventilation. It generally has replaced the term barotrauma as excessive lung volumes.

Vt - tidal volume

V:Q mismatch - ventilation: perfusion mismatch

Wedge see Pulmonary Artery Wedge Pressure (PAWP, PACWP )


Taber’s Cyclopedic Medical Dictionary, F. A. Davis Company, 1998

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