T–W

tachypnea An abnormally rapid RESPIRATION
RATE. BREATHINGis also usually shallow. The nor-
mal respiration rate for healthy adults is 15 to 20
respiratory cycles per minute. In tachypnea the
respiration rate can be two to four times normal.
Breathing may appear labored, and when the
body is not able to meet its needs the person may
look cyanotic (pale or bluish) if the tissues are
receiving inadequate oxygen. Tachypnea is a
symptom of numerous health conditions ranging
from FEVERto serious INFECTIONsuch as PNEUMONIA.
In transient tachypnea of the newborn, an infant
develops a pattern of tachypneic breathing that
lasts 24 to 72 hours after birth. Doctors believe
this form of tachypnea, which resolves without
treatment or complications, occurs as a mecha-
nism for the infant to clear residual AMNIOTIC FLUID
from the LUNGS.
See also CYANOSIS; DYSPNEA; HYPERVENTILATION.

thoracentesis The removal of fluid from the
pleural cavity (the space between the pleural sur-
faces of the lung and thoracic cavity). The doctor
typically uses chest X-RAY, ULTRASOUND, or COM-
PUTED TOMOGRAPHY(CT) SCANto assess the appropri-
ate site for the thoracentesis and may use any of
these imaging procedures to guide the process of
the thoracentesis. After anesthetizing (numbing)
the SKINand tissues at the site, the doctor inserts a
large-gauge needle between the ribs and into the
pleural cavity to withdraw pleural fluid.
Thoracentesis may be diagnostic, in which case
the doctor withdraws a small amount of fluid for
laboratory examination of the cells and any
pathogens it contains. The doctor may conduct
diagnostic thoracentesis to evaluate circumstances
such as

• CHEST PAIN and other symptoms that suggest
  PLEURISYor PLEURAL EFFUSION


• mesothelioma, a CANCERrelated to ASBESTOSISor
  asbestos exposure


• identification of infection (bacterial or tubercu-
  losis)


• staging of LUNG CANCER

Thoracentesis may also be therapeutic, such as

to drain a major pleural effusion. Potential compli-

cations of thoracentesis include vasovagal NERVE

stimulation that causes SYNCOPE(fainting) bleed-

ing, INFECTION, bleeding, and PNEUMOTHORAX. Most

procedures are uncomplicated and discomfort is

usually mild and temporary.

See also ATELECTASIS; STAGING AND CRADING OF

CANCER; THORACOTOMY.

thoracotomy A major OPERATIONin which the

surgeon opens the chest cavity to remove part or

all of a lung. Surgeons most commonly perform

thoracotomy to treat LUNG CANCER or severe

trauma to the lungs. Other reasons for thoraco-

tomy include LUNG ABSCESSthat does not respond

to antibiotic therapy, CHRONIC OBSTRUCTIVE PUL-

MONARY DISEASE(COPD) in which there is significant

alveolar destruction and lung volume resection

may be of benefit, severe BRONCHIECTASIS with

bleeding requiring resection of part of the lung,

biopsy of lung tissue or suspected tumor, and LUNG

TRANSPLANTATION. There are three kinds of thoraco-

tomy:

• wedge resection removes a small segment of
  lung tissue


• lobectomy removes an entire lobe of the lung


• pneumonectomy removes a whole lung

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