Chapter 26 - McGraw-Hill Professional

488 Management of Specific Injuries
SECTION 3 X
protocol are evaluated and established. 14 Two large-bore intravenous
catheters are inserted, and blood is typed and crossmatched.
The patient can be examined for Beck’s triad of
muffled heart sounds, hypotension, and distended neck veins,
as well as for pulsus paradoxus and Kussmaul’s sign. These findings
suggest cardiac injury but are present in only 10% of
patients with cardiac tamponade. The patient undergoes
focused assessment with sonography for trauma (FAST). If the
FAST demonstrates pericardial fluid in an unstable patient
(systemic blood pressure 90 mm Hg), transfer to the operating
room can then occur.
Patients in extremis can require emergency department thoracotomy
for resuscitation. The clear indications for emergency
department thoracotomy by surgical personnel include the
following: 15
fluid. 17 Ultrasonography in this setting is not intended to reach
the precision of studies performed in the radiology or cardiology
suite but is merely intended to determine the presence of
abnormal fluid collections, which aids in surgical decision making.
18 Ultrasonography is safe, portable, and expeditious and
can be repeated as indicated. If performed by a trained surgeon,
the FAST examination has a sensitivity of nearly 100% and a
specificity of 97.3%. 17 As the use of FAST evolves, and highspeed
abdominal CT scans are readily available, the most universally
agreed-upon indication for its use is evaluation for
pericardial blood.
To evaluate more subtle findings of blunt cardiac injury,
such as wall motion, valvular, or septal abnormalities in the
stable patient, formal transthoracic echocardiography (TTE) or
transesophageal echocardiography (TEE) can be obtained.
1. Salvageable postinjury cardiac arrest (e.g., patients who
have witnessed cardiac arrest with high likelihood of
intrathoracic injury, particularly penetrating cardiac
wounds)
2. Severe postinjury hypotension (i.e., systolic blood pressure
60 mm Hg) due to cardiac tamponade, air embolism, or
thoracic hemorrhage
If, after resuscitative thoracotomy, vital signs are regained,
the patient is transferred to the operating room for definitive
repair.
Chest radiography is nonspecific, but can identify hemothorax
or pneumothorax. Other potentially indicated examinations
include computed tomography (CT) scan for trajectory
and laparoscopy for diaphragm injury.
Electrocardiography
In cases of blunt cardiac injury, conduction disturbances can
occur. Sinus tachycardia is the most common rhythm disturbance
seen. Other common disturbances include T wave and
ST segment changes, sinus bradycardia, first- and seconddegree
atrioventricular block, right bundle branch block, right
bundle branch block with hemiblock, third-degree block, atrial
fibrillation, premature ventricular contractions, ventricular
tachycardia, and ventricular fibrillation. Thus, a screening
12-lead ECG can be helpful for evaluation.
Cardiac Enzymes
Much has been written about the use of cardiac enzyme determinations
in evaluating blunt cardiac injury. However, no
relationship among serum assays and identification and prognosis
of injury has been demonstrated with blunt cardiac
injury. 16 Therefore, cardiac enzyme assays are unhelpful unless
one is evaluating concomitant coronary artery disease. 16
Focused Assessment with
Sonography for Trauma (FAST)
Surgeons are increasingly performing ultrasonography for thoracic
trauma. The FAST examination evaluates four anatomic
windows for the presence of intra-abdominal or pericardial
Echocardiography
TTE can have a limited use in evaluating blunt cardiac trauma
because most patients also have significant chest wall injury,
thus rendering the test technically difficult to perform. Its
major use is in diagnosing intrapericardial blood and tamponade
physiology. In stable patients, TEE can be used to evaluate
blunt cardiac injury. Cardiac septal defects and valvular insufficiency
are readily diagnosed with TEE. Ventricular dysfunction
can often mimic cardiac tamponade in its clinical
presentation. Echocardiography is particularly useful in older
patients with preexisting ventricular dysfunction. However,
most blunt cardiac injuries identified by echocardiography
rarely require acute treatment.
Subxiphoid Pericardial Window
Subxiphoid pericardial window has been performed both in the
emergency department and in the operating room with the
patient under either general or local anesthesia. In a prospective
study, Meyer et al. 19 compared the subxiphoid pericardial window
with echocardiography in cases of penetrating heart injury
and reported that the sensitivity and specificity of subxiphoid
pericardial window were 100% and 92%, respectively, compared
with 56% and 93% with echocardiography. They suggested
that the difference in sensitivity may have been due to
the presence of hemothorax, which can be confused with pericardial
blood, or due to the fact that the blood had drained into
the pleura. 19 Although there has been significant controversy in
the past with regard to the indication for subxiphoid pericardial
window, recent enthusiasm for ultrasonographic evaluation has
almost eliminated the role of subxiphoid pericardial window in
the evaluation of cardiac trauma. It is almost never needed in
the ED.
Pericardiocentesis has had significant historical support,
especially when the majority of penetrating cardiac wounds
were produced by ice picks and the (surviving) patients arrived
several hours and/or days after injury. In such instances there
was a natural triage of the more severe cardiac injuries and the
intrapericardial blood had become defibrinated and was easy to
remove. Currently, many trauma surgeons discourage pericardiocentesis
for acute trauma. 10