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14 • Endovascular to Extracorporeal Organ Support for Vascular Trauma and Shock 165
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Gathering the Evidence: Clinical
Study of New Technologies
LAURA J. MOORE and JAN O. JANSEN
Why This Chapter?
Vascular and endovascular trauma management is a rapidly developing eld, which is dominated by medical devices.
The preceding chapters in this section have highlighted key
developments, such as stentgrafts, coils, plugs, resuscitative endovascular balloon occlusion of the aorta (REBOA),
selective aortic arch perfusion (SAAP), and extracorporeal
life support (ECLS) systems. New devices (and modications
of existing ones) are being developed and brought to market
with astonishing speed.
This presents challenges for the clinical evaluation
and adoption of these new technologies. Medical devices
are not subject to the same regulatory requirements as
new medicines, which have to be proven to be effective,
or at least be as effective as existing treatments. Medical
devices, in contrast, only have to be shown to be “safe”
before they can be marketed and used. This makes it difcult for researchers to “keep up,” particularly as indications expand, and devices are modied. In addition, these
new devices may also mandate acquisition of new skills
by the clinicians utilizing them. Buxton’s Law of Health
Services Research which states, “it is always too early to
evaluate, until it is too late,” is highly applicable to endovascular technology. The aim of this chapter is to provide
the reader with an understanding of the process of evaluating new technologies, and the options available to clinicians and researchers.
Medical Devices Are Not
Parachutes
Medical students are often taught that multicenter, prospective, randomized clinical trials represent the highest
quality evidence, and that new treatments should, whenever possible, be evaluated in this way. However, in reality,
clinical trials are difcult to design, expensive, and take a
long time to plan and execute. As a result, some innovators
like to invoke the “parachute metaphor,” particularly when
innovations are conceptually attractive, or have shown
great promise in the preclinical setting, or in small case
series. The arguments usually revolve around statements
such as “we know that it works,” and “you would never
perform a randomized trial of parachutes – it wouldn’t be
ethical.” These claims often reference two satirical articles,
by Smith and Pell (2003) and Yeh et al. (2018), published
in the Christmas editions of the British Medical Journal.
Both of these are worth reading, as they make important
points (albeit tongue-in-cheek).
1,2
It is, of course, true that we would never perform a randomized trial of parachutes – so why do we have to conduct clinical trials? Many clinicians are ummoxed by this argument.
Unfortunately, the parachute metaphor is almost never applicable in medicine.3 Humans are complex, and most therapies
and devices have multiple unintended consequences (some
of which may even be harmful) that complicate the intended
effect.3 This is not true of parachutes. Even more importantly,
a parachute has a number needed to treat that comes very
close to 1.4 Although some people have survived falls from
planes without parachutes, or complete malfunctions of
their parachutesa; and although there are deaths despite a
parachute being used, the risk is very low,
reduction in mortality is therefore very close to 100%. There
are no medical therapies that offer comparable benets.4
Simply put, medical devices are not parachutes – and therefore have to be carefully and thoroughly evaluated.
b,5
and the absolute
The Evaluation of Surgical
Innovation
COMPLEX INTERVENTIONS
Vascular surgery and endovascular therapies are “complex
interventions,”6 dened as procedures consisting of several
interacting components or involving the use of difcult
or complex techniques, which may be applied in various
ways.6 Although the evaluation of surgical and interventional techniques in general proceeds through stages similar to those for drug development, there are important
differences. Indeed, some aspects of the evaluation of surgical technique and technology have more in common with
the evaluation of psychological and physical therapies,
than drug development.
Several bodies have made recommendations regarding the
study of complex interventions. The UK Medical Research
Council recommends that the assessment should be phased;
include the use of experimental rather than observational
designs whenever possible; measure outcomes as well as
process; and report detailed descriptions of interventions to
improve reproducibility, as well as evidence synthesis. The
IDEAL Collaboration – an international group of surgeons,
a
Modern parachute rigs consist of two canopies, a main and a reserve,
although evaluations of the effectiveness of these devices usually refers
to the system as a whole.
b
In 2018, there were 13 deaths related to civilian skydiving in the United
States, out of an estimated 3.5 million jumps. Four of these deaths were
“medical,” rather than related to trauma.
6
166
15 • Gathering the Evidence: Clinical Study of New Technologies 167
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researchers, journal editors, methodologists, and statisticians committed to producing, disseminating, and evaluating quality research in surgery – describes ve stages of
innovation, tailored to the surgical setting, with each stage
dened by a set of recommendations.
6
THE IDEAL STAGES OF SURGICAL INNOVATION
The five stages of surgical innovation are shown in
Table 15.1.6 It is easy to see how this scheme applies to
the study of new vascular and endovascular technologies although, in practice, there is overlap, and evaluation
rarely proceeds linearly. Nevertheless, the underlying concepts are helpful.
Stage 1 (innovation) is about proof of concept (such as
the rst use of an aortic occlusion device), with the aim at
this point being description, highlighting technical achievement, as well as dramatic successes (“parachutes”) – or
disasters. Only a small number of patients will be involved,
and the results are conveyed using structured case reports.
Stage 2a (development) involves the planned use of the
procedure or device in an initial small group of patients, to
support experience with its rst use and often to rene or
modify the precise technique or technology, sometimes leading to technical modications. The IDEAL Collaboration recommends that protocols for prospective development studies
be registered before patient recruitment begins, describing
patient selection principles, operative methods, and outcomes
to be measured. Similarly, the nature and timing of technical
modications should be meticulously recorded.
Evaluation progresses to exploration, stage 2b, once technical issues have been resolved. Experience with the procedure may still be scarce at this stage, and outcomes with
larger numbers of patients are needed before a randomized
6
clinical trial that compares the new procedure or device with
traditional management is feasible. Data should be captured
systematically for every patient having the procedure, paying
careful attention to adverse outcomes and patient safety. A
prospective research database is usually the best approach.
Carefully planned, prospective but uncontrolled clinical studies could run as parallel additions to smaller feasibility or
explanatory randomized clinical trials.
6
Previous stages focused on the development of a new technique and the description of its outcomes; stage 3 (assessment) aims to assess effectiveness against current standards.
Randomized trials of surgical techniques are not always necessary, particularly when an advance is clear and substantial.
Alternatives include parallel group nonrandomized studies,
such as those using propensity scores. However, these studies are prone to unmeasured confounding and are regarded
as problematic in trauma patients. For example, if a propensity score only includes admission vital signs, and does not
account for the response to resuscitation, matched patients
6
(and groups) may not be comparable after all. Interrupted
time series analyses are another option. These designs allow
rapid and simple comparison with a preinterruption group,
but cannot eliminate selection bias. However, as stated previously, most new innovations are not parachutes, and only
offer marginal improvements, which are prone to overly
optimistic assessment by their developers. Randomized trials
should therefore be the default option at this stage.
Methodological and Practical
Challenges
Clinical trials in trauma patients, and clinical trials of medical devices in particular, face a number of challenges. Firstly,
6
Table 15.1 Stages of Surgical Innovation
1: Idea 2a: Development 2b: Exploration 3: Assessment 4: Long-Term Study
Purpose Proof of concept Development Learning Assessment Surveillance
Number
and types of
patients
Number
and types of
surgeons
Output Description Description Measurement, comparison Comparison; complete
Intervention Evolving; proce-
Method Structured case
Outcomes Proof of con-
Abbreviated from McCulloch P, et al. No surgical innovation without evaluation: the IDEAL recommendations. Lancet. 2009;374(9695):1105–1112.
Single digit; highly
selected
Very few;
innovators
dure inception
reports
cept; technical
achievement;
disasters; dramatic
successes
Few; selected Many; may expand to
Few; innovators and
some early adopters
Evolving; procedure
development
Prospective development studies
Mainly safety; technical and procedural
success
mixed; broadening
indication
Many; innovators, early
adopters, early majority
Evolving; procedure refinement; community learning
Research database;
explanatory or feasibility
randomized clinical trial
(RCT) (efficacy trial); disease
based (diagnostic)
Safety; clinical outcomes
(specific and graded);
short-term outcomes;
patient-centered
(reported) outcomes;
feasibility outcomes
Many; expanded indications (well defined)
Many; early majority All eligible
information for non-RCT
participants
Stable Stable
RCT with or without
additions/modifications;
alternative designs
Clinical outcomes (specific
and graded); middle- and
long-term outcomes;
patient-centered
(reported) outcomes;
cost-effectiveness
All eligible
Description; audit,
regional variation;
quality assurance; risk
adjustment
Registry; routine
database (e.g., Surgical
Clinical Outcomes
Assessment Program,
National Surgical Quality
Improvement Program)
Rare events; long-term
outcomes; quality
assurance
168 SECTION 3 • Emerging Technologies and New Approaches to Vascular Trauma and Shock
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there is the issue of equipoise. If an intervention has already
been approved by the Food and Drug Administration, and is
therefore available for use, and in use, clinicians may have
formed opinions regarding its benet, and may no longer
have sufcient equipoise to enroll patients in a trial which
will result in half of the participants not receiving the intervention. In the case of new technologies, it is likely that high
volume, high acuity centers may be early adopters of a new
technology. If they believe this technology to be a benet to
patients, they may implement the technology as standard of
care in their center, even in the absence of randomized clinical trial data. If a randomized clinical trial of the technology was designed and funded a later date, that high-volume
center would be desirable in terms of study patient recruitment, but might lack equipoise and be unable to participate.
A comprehensive cohort design, with randomized arms as
well as patient (or physician) “preference” arms can help to
overcome this issue – but these designs are difcult to analyze, and if all or most of the patients (or clinicians) choose a
“preference” arm, the study is unlikely to be successful.
The next big issue for trauma trials is obtaining informed
consent. Most vascular trauma patients require urgent or
even emergent treatment, and frequently lack capacity to
consent for themselves. There is often not enough time to
seek informed consent from patients, or their surrogate decision makers, for them to be enrolled in the trial. Although
most countries now have a legal and ethical framework to
conduct research in emergency settings, while safeguarding patients’ rights and safety, securing the necessary permissions can be complex, costly, and time-consuming.
In the United States, it is possible to conduct a trial using
exception from informed consent (EFIC) rules. This allows
clinician-scientists to perform much needed research on
emergent patients. However, such trials must meet strict criteria. Although each institution varies, receiving approval
for EFIC requires a number of community consultation
meetings and public notication via advertisements, traditional media, and social media, informing members of the
community about the trial.
7–9
Individuals can then opt out
of the trial, if desired.
Another challenge area is patient availability. The number of trauma patients with vascular injuries who could
participate in a clinical trial is often small. Even when all
eligible patients are enrolled (which is rarely possible), the
numbers may not be sufcient to demonstrate “statistical
signicance,” even when a genuine difference exists. There
are a number of options available to reduce sample size.
Lengthening the accrual time, broadening the eligibility criteria, and adding trial sites are the most common, and most
intuitive. Other possibilities include using a continuous
outcome, which is more “information-heavy,” accepting
lower power, relaxing α, or moving to one-sided signicance
tests.10 However, even with these measures, calculated minimum sample sizes may still be unworkable.
The Role of Innovative Clinical
Trial Designs
Innovative clinical trial designs include adaptive and Bayesian
trials. Adaptive trials are trials in which interim analyses are
used to trigger predetermined modications to the conduct
of the trial – such as discontinuing arms, or changing the
allocation ratio. Bayesian trials rely on an alternative analytical framework. Bayes' theorem mathematically combines
prior information (data and beliefs) with new data (e.g., the
results of a new trial) to yield an updated summary of knowledge and the remaining uncertainty.
11–13
The key advantages
include greater efciency and power to detect differences,
and a more interpretable output. Bayesian inference directly
estimates the probability that a conclusion is true, given the
data observed in an experiment, without any requirement
for a binary conclusion.
11,12
Traditional (also known as “frequentist”) statistics, in contrast, focus on the probability that
the observed differences in outcomes between two groups,
or differences more extreme, could have occurred by chance
alone. If the “P-value” is less than .05, the usual conclusion is that chance alone cannot account for the differences
11,13
seen.
This approach, although familiar, is open to misin-
terpretation, and wastes information.
A recent Bayesian post-hoc analysis of the Extracorporeal Membrane Oxygenation (ECMO) to Rescue Lung
Injury in Severe Acute Respiratory Distress Syndrome
(EOLIA) trial,14 by Goligher et al., highlights the limitations
of the frequentist framework, and the value of the Bayesian approach.15 This trial, which examined whether early
ECMO reduced mortality for patients with severe ARDS,
was stopped early for futility, concluding that ECMO did not
reduce 60-day mortality (P = .09). In contrast, Goligher
et al.’s Bayesian analysis, which incorporated a range of
“informative priors” to quantify existing beliefs and evidence, found it highly probable that ECMO does lower mortality. For example, using a minimally informative prior, the
posterior probability of any reduction in the relative risk of
death at 60 days was 96%. Conversely, the posterior probability of an absolute reduction in mortality of at least 2%
was 92%. However, the posterior probability of an absolute risk reduction of 20% or more, which is what the trial
had been designed around, was only 2%. This latter result
is in keeping with the original, frequentist analysis.15 The
Bayesian analysis, therefore, provided a more informative
set of interpretations than that provided by the frequentist
analysis, demonstrating the power of a Bayesian analysis.
The UK-REBOA trial, a randomized trial of REBOA in
exsanguinating trauma patients, which is currently being
conducted in the United Kingdom, uses a similar framework, although the design of this trial was Bayesian from
the outset.
13
Conclusion
Innovations in vascular and endovascular technology have
transformed, and will continue to transform, the care of
patients with vascular injuries. However, most treatments
have adverse as well as intended effects – REBOA is a case in
point – and the rigorous evaluation of these new technologies
is more important than ever. The IDEAL framework usefully
describes the stages of innovation, and the types of studies
that may be helpful at each stage. Although not all interventions require a randomized clinical trial for their evaluation,
most eventually do. Furthermore, when clinical trials are
required, these will often require innovative designs, which
are more complex, but also more interpretable.
15 • Gathering the Evidence: Clinical Study of New Technologies 169
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References
1. Smith GC, Pell JP. Parachute use to prevent death and major trauma
related to gravitational challenge: systematic review of randomised
controlled trials. BMJ. 2003;327(7429):1459–1461.
2. Yeh RW, Valsdottir LR, Yeh MW, etal. Parachute use to prevent death
and major trauma when jumping from aircraft: randomized controlled trial. BMJ. 2018;363:k5094.
3. Morgenstern J. Most medical practices are not parachutes 2018
[3/3/2019]. Available from: https://rst10em.com/parachutes/.
4. Hayes MJ, Kaestner V, Mailankody S, Prasad V. Most medical practices are
not parachutes: a citation analysis of practices felt by biomedical authors
to be analogous to parachutes. CMAJ Open. 2018;6(1):E31–E38.
5. Crouch J. A record low – the 2018 fatality summary. Parachutist.
2019;714.
6. McCulloch P, Altmann DG, Campbell WB, et al. No surgical inno-
vation without evaluation: the IDEAL recommendations. Lancet.
2009;374:1105–1112.
7. Harvin JA, Podbielski JM, Vincent LE, etal. Impact of social media on
community consultation in exception from informed consent clinical
trials. J Surg Res. 2019;234:65–71.
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tion. 2013;128(3):267–270.
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Bayesian? Reanalysis of results of a clinical trial of extracorporeal
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SECTION 4
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T he M an ag em ent of
Vascular Trauma
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Cardiac, Great Vessel, and
Pulmonary Injuries
DAVID V. FELICIANO and JOSEPH J. DUBOSE
Introduction
Penetrating injuries to the heart and great vessels result in
signicant prehospital mortality (50% to 75% for cardiac
wounds), so the numbers of patients undergoing operations for such injuries are small even in the busiest civilian
centers or wartime hospitals. The presentation is different
for penetrating wounds to the nonhilar vessels of the lung
parenchyma. With a systolic pressure of 25 mm Hg in the
pulmonary artery and its branches, bleeding from injury to
pulmonary parenchymal vessels requires thoracotomy in
only 5% to 10% of patients. After blunt thoracic trauma,
the majority of injuries involve the chest wall (i.e., fractured ribs) or lung (i.e., pneumothorax, hemothorax). As
such, only 7% to 8% of patients with this injury pattern
require thoracotomy or median sternotomy. In all patients
with thoracic trauma, the most common indications for
thoracotomy are hemorrhage from the lung, major arterial
injury in the superior mediastinum or supraclavicular area,
or a penetrating wound of the heart.
Evaluation and Management in
the Emergency Center
MECHANISM OF INJURY
Penetrating wounds that injure the heart, the thoracic great
vessels, or the hilum of the lung are often in a location referred
to as the “cardiac box,” which is the area between the nipples
from the sternal notch to the xiphoid process. Based on an
autopsy study in 2017, this denition should be expanded
to the posterior midline of the left hemithorax.1 Other penetrating wounds that increase the likelihood of injuries to
these structures are those that traverse the mediastinum (i.e.,
transmediastinal wounds) and those to the thoracic outlet.
With blunt trauma to the chest, particularly from motor
vehicle crashes, signicant injuries to the heart and great
vessels (and, occasionally, the lung) may occur whether
or not the victim is restrained. Unrestrained victims with
frontal or lateral impact can sustain all of the previously
described deceleration or direct blunt injuries to the chest
wall or intrathoracic structures. The most classic example
of a deceleration injury is when the forward motion of the
victim's thorax stops abruptly on contact with the hub of the
steering wheel. This mechanism may cause varying degrees
of traumatic disruption of the descending thoracic aorta,
most commonly at the level of the ligamentum arteriosum.
Depending on the position of any shoulder-harness restraint
and the direction of impact, the innominate, carotid, subclavian, or vertebral arteries may also be prone to injury. Blunt
thoracic vascular injury has also been reported as a result
of air-bag ination and is more prone to occur in women of
small stature or in children.
ADVANCED TRAUMA LIFE SUPPORT (ATLS):
PRIMARY SURVEY, INITIAL RESUSCITATION,
EMERGENCY CENTER THORACOTOMY
Profoundly hypotensive patients with external hemorrhage
at or near the thoracic outlet, those with hemorrhage into
the pericardial sac or pleural cavity, or those with cardiac
tamponade (diagnosis by ultrasound) should undergo rapid
sequence or emergent endotracheal intubation in the emergency department. Awake patients with more normal hemodynamics with intrapleural blood or a pneumothorax, with
or without tension physiology, should have a thoracostomy
tube inserted in the 5th intercostal space at the midaxillary
line. If this maneuver drains 1000 mL or more of blood in
the rst 15 minutes after tube insertion, the patient should
be moved emergently to the operating room (OR). In this
scenario, the patient should be placed on the operating table
in the supine position with the anesthesiologist and operating team present. If another 200 mL of blood drains out of
the thoracostomy tube in the next 15 minutes, the patient
should be intubated in preparation for operation.
The decision as to whether the incision should be an
anterolateral thoracotomy or a median sternotomy will
depend on the entrance location and trajectory of any penetrating wound, the results of the thoracic and pericardial
ultrasound, and the hemodynamic condition of the patient.
If the amount of bloody drainage stops before 1200 mL and
the patient has normal or near-normal hemodynamics, he
or she should be moved to the intensive care unit (ICU) for
close observation. Resumption of bleeding from the thoracostomy tube at a rate of 100 to 200 mL/h over the next
2 to 4 hours should prompt urgent thoracotomy or median
sternotomy.
Any patient who is hypotensive from a pneumothorax,
bleeding, or cardiac tamponade requires large-bore intravenous access for resuscitation, including placement of
either 14-gauge extremity vein catheters, large-bore 7.5Fr central venous catheter(s), or both. If there is concern
about the original wounding mechanism having injured
one of the subclavian veins, a contralateral upper extremity
or subclavian vein should be used for venous access. Thoracic wounds in the expanded cardiac box or those with
a transmediastinal trajectory that might have injured the
171
172 SECTION 4 • The Management of Vascular Trauma
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superior vena cava should prompt placement of resuscitation lines into the common femoral veins.
Although the resuscitation uid for patients with thoracic trauma was lactated Ringer's solution for many years,
hypotensive patients (systolic blood pressure less than
90 mm Hg) are now managed with a strategy referred to
as “damage control resuscitation” (DCR).2 In essence, this
protocol involves avoiding administration of any crystalloid
solutions if the patient is awake and has a recordable blood
pressure. Initial application of this hypotensive resuscitation strategy allows for the fact that needless administration
of any uid aimed at achieving an arbitrary systolic blood
pressure may lead to or worsen bleeding that has otherwise
nearly stopped (i.e., “pop the clot” phenomenon).
Avoidance of crystalloid solutions such as normal saline
or lactated Ringer's also stems from recognition that even
small amounts of these uids may dilute clotting factors and may lead to a condition referred to as dilutional
coagulopathy. DCR is based on the early and balanced use
of packed red blood cells (pRBC), thawed plasma, and platelets. Studies initiated from the wars in Iraq and Afghanistan
demonstrated that the balanced use of pRBC, plasma, and
platelets in a 1:1:1 ratio as part of a DCR strategy conveyed
a mortality benet to severely injured patients. Recent military studies have reported a mortality benet with the use
of the antibrinolytic medication tranexamic acid (TXA),
as well as administration of supplemental cryoprecipitate
as part of the DCR strategy.
Resuscitative endovascular balloon occlusion of the
aorta (REBOA) passed through the common femoral artery
has replaced emergency center thoracotomy for resuscitation in patients with trauma isolated to the abdomen, pelvis, or lower extremities. Emergency center thoracotomy for
resuscitation and bleeding control continues to be indicated
in a highly selected group of patients. This maneuver with
thoracic trauma, also referred to as resuscitative thoracotomy, is performed in hospitals that do not have an OR in or
immediately adjacent to the emergency department. Algorithms, quality improvement data, and reviews of outcomes
have helped rene the indications for this procedure.
Reasonable indications to perform an emergency center
thoracotomy in an injured patient are as follows
3–7
3–5
:
1. Penetrating thoracic wound with agonal physiology or
recent cardiac arrest
2. Uncontrolled bleeding from the thoracic inlet or a thora-
costomy tube
3. Suspected subclavian vessel injury with intrapleural
exsanguination
4. Need for open cardiac massage or occlusion of the
descending thoracic aorta before laparotomy in the OR
(REBOA not available)
5. Need for open cardiac massage or clamping of the de scend-
ing thoracic aorta when countershock or closed-chest
cardiac massage is ineffective (i.e., cardiopulmonary
arrest)
Relative indications include a recent cardiac arrest associated with a ail or other chest wall abnormality (difcult
external cardiac massage) or pregnancy (to save the child).
Strong contraindications for the use of resuscitative thoracotomy include penetrating trauma with no signs of life in
the eld and blunt trauma with no signs of life on arrival in
the emergency center.
8
A left anterolateral thoracotomy at the lower edge of the
male nipple is performed when a penetrating left thoracic
wound is present in an agonal or arrested patient. When a
penetrating right thoracic wound is present and the patient
is agonal on arrival, a bilateral anterolateral thoracotomy
(i.e., clamshell thoracotomy) is performed. If intrapleural
exsanguination from a suspected injury to a subclavian vessel is believed to be present, an anterolateral thoracotomy at
a higher intercostal space is appropriate. The primary goals
of either a unilateral anterolateral or a bilateral anterolateral thoracotomy are to control bleeding from a wound
to the heart, a great vessel, or the lung, release a cardiac
tamponade, or perform internal cardiac massage. Whether
suture repair of the injured organ or vessel is appropriate
in the emergency department will depend on the following
factors: (1) magnitude of the injury; (2) success of temporary bleeding control maneuvers; (3) quality of lighting;
and (4) availability of instruments and sutures.
An additional and important goal of resuscitative thoracotomy is to cross-clamp the descending thoracic aorta to
maintain any remaining central aortic pressure and perfusion to the coronary and carotid arteries. One must be mindful in these scenarios that applying a cross-clamp to the
descending thoracic aorta is more difcult through a higher
left-sided thoracotomy incision. Thoracic aortic clamping is
performed by rst lifting the posterolateral edge of the left
lung out of the hemithorax. Once the mediastinal pleura
over the descending thoracic aorta and vertebral bodies is
visualized, it is opened with scissors. Next, the descending
thoracic aorta is encircled with the surgeon's left index nger before the cross clamp is applied. Subsequent maneuvers for cardiac massage or repair include a longitudinal
pericardiotomy above the left phrenic nerve, exposure of the
cardiac wound or rupture, and the use of ngers, staples,
sutures, or balloons for bleeding control (Figs. 16.1–16.4).
Because of the cost and low survivability of emergency
center thoracotomy, the technique has been used more selectively in recent years. The reported survival rate of 7% to
10% is deceptive as it includes patients with a variety of injuries, while patients with penetrating cardiac wounds have
signicantly better outcomes.9 In an old report by Ivatury
et al., 16 of 22 patients with penetrating cardiac injury who
arrived in the emergency center without “detectable vital
signs, cardiac activity, or spontaneous respirations” were
able to have restoration of cardiac function with resuscitative thoracotomy.10 In this same report, eight patients (36%)
survived without neurologic sequelae. A more recent (2009)
report on 283 patients undergoing emergency center thoracotomy for penetrating injury to the heart and great vessels
documented worse outcomes including a survival rate of
24% in those with stab wounds and only 3% in those with
gunshot wounds.11 The injury scenario with the highest survival rate following emergency center thoracotomy is cardiac
tamponade from an isolated, anterior cardiac stab wound in
a patient presenting with measurable vital signs following a
short prehospital transport.
For patients with penetrating wound(s) that may involve
the heart, thoracic aorta, or great vessels and who are
hemodynamically normal, it is appropriate to image the
thorax to better characterize the presence and location of
16 • Cardiac, Great Vessel, and Pulmonary Injuries 173
sac
A
B
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injury. This can be accomplished with a chest x-ray, which
may demonstrate a hematoma in the superior mediastinum
or in the supraclavicular area, a surgeon-performed ultrasound, or a contrast-enhanced CT scan or CT arteriography.
The Injured Heart
HISTORY
Asensio et al. have reviewed the unsuccessful attempts at
cardiac repair by Cappelen in Norway and Farina in Italy
that preceded Ludwig Rehn's successful repair of a wound
to the right ventricle in 1896.
12–15
L.L. Hill of Montgomery,
Pericardial sac
Phrenic nerve
Alabama, is credited with the rst successful delayed repair
of a stab wound to the left ventricle in the United States in
12,13,16
1902.
In the modern era, the vast majority of cardiac injuries are from penetrating wounds and are treated
in urban trauma centers.17 Blunt cardiac injuries occur
mostly after head-on motor vehicle crashes, can be caused
by air bags, and have a signicant mortality that is often
related to a delay in diagnosis.
18–20
INCIDENCE
Penetrating Trauma
Patients with penetrating cardiac injuries, especially from
gunshot wounds, have a 50% to 75% mortality rate at the
Left
lung
Right
lung
Sternum
(cut)
Left
lung
Pericardial
Fig. 16.1 (A) A left anterolateral thoracotomy incision is made at the inferior edge of the male left nipple. In women, the left breast is retracted superiorly and the incision is made at the midaspect of the left hemithorax. The Finochietto retractor is placed with the handle facing the left side of the
patient. (B) Bilateral anterolateral thoracotomy.
174 SECTION 4 • The Management of Vascular Trauma
Pe
lung
Repair
massage
Left lung
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Aorta
Phrenic nerve
ricardial sac
Left
Fig. 16.2 In a patient with profound hypotension (or who has suffered
a cardiac arrest), the left lung is lifted out of the left chest by the left
hand of the surgeon or by an assistant on the other side of the table.
Having used the tip of an aortic clamp to spread the pleura above and
below the mid-descending thoracic aorta, the surgeon is using the left
index finger to encircle the aorta and pull it to the left so that the clamp
can be applied under direct vision. (Adapted from Copyright, Baylor
College of Medicine, Houston, 1980.)
Swing heart into
left chest
A
1
Fig. 16.3 In the patient with a wound through the pericardial sac, with
blood underneath the pericardium, or with asystole, a left longitudinal
pericardiotomy is made 1 to 2 cm above the left phrenic nerve from the
great vessels superiorly to the left hemidiaphragm inferiorly. (Adapted
from Copyright, Baylor College of Medicine, Houston, 1980.)
B
Fig. 16.4 (A) After the left pericardiotomy, the heart is swung into the left chest. (B) Atrial wounds are repaired over a Satinsky clamp, whereas ventricular wounds are repaired by sewing under a finger and under adjacent coronary arteries. (C) Patients with profound hypotension, electromechanical
dissociation, or asystole undergo two-handed internal cardiac massage. (Adapted from Copyright, Baylor College of Medicine, Houston, 1980.)
Repair 2
Repair 3
Cardiac
C
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