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Diaphragmatic Injuries
VictoriaSharp andIsaacSchmied
105
Concept
Many times, patients may be asymptomatic initially. The
pressure gradient between abdomen and thorax may lead to
herniation of abdominal viscera into the thoracic cavity
resulting in compression of the heart and lung. Cardiac compression results in diminished cardiac output due to decreased
prell, while pulmonary compression results in diminished
total lung capacity. In severe cases of pulmonary compression, shunt physiology may develop. Additionally, the herniated viscera are at risk of strangulation.
Way aQuestion May BeAsked
“A 24-year-old man presents to the trauma bay following a
stab wound just left of the xiphoid at the costal margin. Initial
evaluation suggests patent airway and bilateral breath
sounds; BP is 140/85, HR 114, and SpO2 97% on room air.”
Keep a diaphragmatic injury in the back of your mind
whenever the examiner gives you a penetrating injury to the
chest or upper abdomen. Do not stray from the ABCDEs of
trauma. A diaphragmatic injury may also be identied during
operative exploration for other reasons. Additionally, the
patient may manifest symptoms in a delayed fashion by
developing cardiac dysfunction, pulmonary dysfunction,
and/or sequela of strangulated viscera.
V. Sharp
Trauma, Acute, and Critical Care Surgery, Trinity Health Ann
Arbor Hospital, Ypsilanti, MI, USA
e-mail: victoria_sharp@ihacares.com
I. Schmied (
Trinity Health Ann Arbor Hospital, Ypsilanti, MI, USA
e-mail: isaac.schmied@trinity-health.org
*)
How toAnswer?
History
Provided by EMS and patient. Inquire about any suspicion
for concomitant blunt injury, i.e., “Was the patient stabbed
during a st ght or was it an isolated stabbing?”.
Physical Examination
• Always start with the ABCDEs of the primary survey and
then progress to a head-to-toe exam for the secondary survey to avoid missed injuries. Any change in patient’s clinical status should prompt you to return to and run through
the ABCDEs yet again.
• Airway: Stated to be intact.
• Breathing: Bilateral breath sounds.
• Circulation: Hemodynamically normal.
• Disability: Assess GCS, pupil, and for any gross motor
decits.
• Exposure: Remove all clothing to adequately evaluate the
patient and apply warm blankets.
Diagnostic Tests
• Full laboratory panel including CMP, CBC, UA, troponin,
lipase, EtOH, and UDS, and consider thromboelastographic evaluation.
• Thoracoabdominal stab wounds (between the anterior
axillary lines laterally, the nipple line superiorly, and
approximately the costal margin inferiorly) must be evaluated with a chest X-ray and pericardial ultrasound on a
FAST exam.
• Signs of diaphragmatic injury on CXR: elevated hemidiaphragm (only ~61% accurate), bowel content in chest
cavity such as air-uid levels above the diaphragm, NG
tube tip looping back into the chest, atelectasis, pneumothorax or hemothorax, pulmonary contusion.
© The Author(s), under exclusive license to Springer Nature Switzerland AG 2025
M. Neff et al. (eds.), Passing the General Surgery Oral Board Exam, https://doi.org/10.1007/978-3-031-78244-2_105
351
352
V. Sharp and I. Schmied
• Further imaging obtained only if the patient remains stable. CT evaluation is most helpful with multidetector CT
that is high-resolution (64-slice or greater). CT is
73–100% sensitive and 75–100% specic. It is most sensitive and specic for diaphragmatic injury in blunt
trauma due to the typically larger defect size. In penetrating injuries, the defect size is ≤2cm in size 80% of the
time.
• Diagnostic laparoscopy: All stable patients with left-sided
penetrating thoracoabdominal injuries should undergo
laparoscopy to evaluate for diaphragm injury within
8–12h after the injury. This allows hollow viscus or other
operative injuries to present themselves which may otherwise be missed if immediate exploration is not
performed.
• Thoracoscopy: Consider VATS evaluation of diaphragmatic injury if there is a retained hemothorax to allow for
washout of chest, treatment of coexisting thoracic injuries, conrmation of chest tube positioning, and evaluation/management of diaphragm injuries.
Treatment
• Hard indication to proceed to the OR after thoracoabdominal stab wounds: hemodynamic instability, peritonitis,
evisceration, hematemesis, blood per NG, blood per rectum, or impalement.
• Unstable patients or hard indications for operative exploration→OR for exploratory laparotomy.
– If diaphragmatic injury is identied, it should be
repaired at index operation after stability has been
achieved by addressing other injuries.
– Diaphragm injury typically does not heal and is
expected to worsen over time.
– If remains unstable and damage control surgery is per-
formed, diaphragmatic repair can be deferred to later
time after patient becomes stable
• Stable patient→diagnostic laparoscopy or thoracoscopy
8–12 h after injury. This allows hollow viscus or other
operative injuries to present themselves which may otherwise be missed.
• Supraumbilical port with additional ports at the midclavicular and anterior axillary line on side of suspected
injury.
– If feasible without enlarging the defect, evaluate the
thoracic cavity through the diaphragmatic injury to
rule out additional thoracic injuries.
– VATS is useful for patients with retained hemothorax,
suspected right-sided injuries, multiple prior abdominal surgeries, or large body habitus.
• For stable patients without other indications for operative
exploration, can consider using multidetector CT with
64-slice or higher resolution to evaluate for diaphragm
injury. Inclusion criteria for CT evaluation only: must be
able to reconstruct the wound tract, ensure the tract does
not traverse through or near the diaphragm, no sign of
contiguous injury on either side of the diaphragm, no
hemothorax. If patients undergo CT evaluation only,
patients must have close follow-up post-discharge and
should repeat CT evaluation after 6–12months.
Principles forOperative Repair
• Reduce any herniated viscera and evaluate for ischemia.
• If wound is contaminated, irrigate and debride to healthy
tissue.
• Reapproximate the diaphragm with nonabsorbable
sutures such as Ethibond or Prolene in a running locking
suture and consider reinforcement with interrupted
sutures.
• Larger defects may require synthetic, nonabsorbable
mesh placement if no contamination is present or more
advanced reconstruction techniques including rotational
or myocutaneous muscle aps.
• Test the repair by submerging the repair under saline and
request a Valsalva maneuver from anesthesia colleagues.
• Chest tube placement for prevention/management of
pneumothorax.
• Chest tube placement for wide drainage of contaminated
tissue.
Common Curveballs
• Any change in the patient’s condition should prompt you
to restart evaluation with ABCs.
• Make sure to keep in mind both intrathoracic and intraabdominal pathology as potential causes of deterioration.
• Left thoracoabdominal stab wounds require evaluation of
the diaphragm. If no hard indication to proceed to OR
initially, laparoscopy for evaluation of the diaphragm
should be performed 8–12h from the injury.
• A pericardial effusion should be considered hemopericardium until proven otherwise. Proceed directly to the OR
for pericardial window and if positive for blood median
sternotomy.
• Negative pericardial ultrasound does not rule out a cardiac injury in patients with a left-sided hemothorax as the
hemopericardium may be decompressing into the left
chest. Proceed to the OR for subxiphoid pericardial window to evaluate for hemopericardium.
• Flank and back stab wounds should be evaluated with
multidetector high-resolution CT scan (preferably with
IV, PO, and rectal contrast).
105 Diaphragmatic Injuries
353
Clean Kills
• Not following ABCs of ATLS
• Not returning to ABCs if a patient’s clinical status
deteriorates
• Proceeding to OR for exploratory laparotomy in an unstable patient but not considering intrathoracic pathology
• Not evaluating for hemopericardium
• Not recognizing that hemopericardium may be decompressing into the chest in the setting of a negative pericardial ultrasound with a left hemothorax
Summary
Traumatic diaphragmatic injury should remain on
your differential for both blunt and penetrating injuries. Diaphragm injuries may be identied during
operative evaluation of other injuries, or patients may
present in a delayed fashion with signs of incarceration of abdominal viscera or compromised cardiac or
pulmonary function. In patients without indication for
operative exploration, thoracoabdominal stab wounds
should be explored 8–12h after injury with laparos-
copy or thoracoscopy. Diaphragmatic injuries should
be repaired at time of identication if the patient is
stable as these injuries are expected to progressively
enlarge.
Bibliography
Bif WL, Ciof WG.Diaphragm. In: Feliciano DV, Mattox KL, Moore
EE, editors. Trauma, 9th ed. McGraw Hill; 2020. accesssurgery.
mhmedical.com/content.aspx?aid=1175137988. Accessed 20 Aug
2023.
Clinical challenges in trauma surgery: approach to stab wounds of the
torso. Behind the knife: the surgery podcast. https://behindtheknife.
org/podcast/clinical- challenges- in- trauma- surgery- approach- tostab- wounds- of- the- torso/. Accessed 1 Aug 2023.
Martin MJ, Brown CVR, Shatz DV, etal. Evaluation and management of
abdominal stab wounds: a Western Trauma Association critical decisions algorithm. J Trauma Acute Care Surg. 2018;85(5):1007–15.
https://doi.org/10.1097/TA.0000000000001930.
McDonald AA, Robinson BRH, Alarcon L, etal. Evaluation and man-
agement of traumatic diaphragmatic injuries: a practice management guideline from the Eastern Association for the Surgery of
Trauma. J Trauma Acute Care Surg. 2018;85(1):198. https://doi.
org/10.1097/TA.0000000000001924.
Sekusky AL, Lopez RA. Diaphragm trauma. In: StatPearls.
StatPearls Publishing; 2023. http://www.ncbi.nlm.nih.gov/books/
NBK557647/. Accessed 19 Aug 2023.
Emergency Airway
AlexanderSimmonds andSayuriJinadasa
106
A denitive airway is dened as a tube placed in the trachea
with the cuff inated below the vocal cords. There are three
types of denitive airways: orotracheal tubes, nasotracheal
tubes, and surgical airways (cricothyrotomy and tracheostomy). A denitive airway is needed for airway protection in
the setting of maxillofacial or neck trauma, risk of aspiration,
or poor mental status or improved oxygenation or ventilation
in the setting of tachypnea, hypoxia, or hypercarbia.
Airway Management inTrauma Patients
Concept
The initial step in managing trauma patients is to evaluate
their airway. Patients may present with a broad set of airway
concerns, ranging from mental status changes that preclude
them from maintaining their airway to medication reactions
to traumatic injuries that create anatomic obstruction or
bleeding that compromises the airway. The key is to secure
the airway swiftly and safely.
Blunt Trauma
Way Questions May BeAsked
“A 56-year-old man presents to the emergency department
30 min following a motor vehicle crash in which he was the
unrestrained driver ejected at 45 MPH. Per EMS he was verbal and responded appropriately on scene, but over the
course of the 15-min transport, he has become progressively
A. Simmonds
Department of Surgery, Virginia Commonwealth University,
Richmond, VA, USA
e-mail: alexander.simmonds@vcuhealth.org
S. Jinadasa (
Division of Acute Care Surgical Services, Department of Surgery,
Virginia Commonwealth University, Richmond, VA, USA
e-mail: sayuri.jinadasa@vcuhealth.org
*)
more drowsy and unresponsive, now groaning to painful
stimuli.”
This is a common real-life scenario in which a patient
presents with poor mental status following blunt trauma.
Common differential diagnoses include head injury, cervical
spine injury, or intoxication, any of which can lead patients
to be unable to maintain their airway.
History
• Obtaining history should be done quickly; sometimes it is
not possible to do so based on the acuity of the scenario.
• Determine antecedent events, such as mechanism of
trauma, intake of medications, and ingestion of
intoxicants.
• Determine if patient has required previous intubation and,
if so, if they had a difcult intubation.
Physical Exam
• Connect to monitor and note vital signs, particularly pulse
oximetry.
• Ensure C-spine is stabilized.
• Evaluate airway.
– Note any vocalization or airway noises.
– Mouth opening.
– Mallampati scoring.
– Mandibular protrusion.
– Presence or absence of teeth.
– Neck mobility.
– C-spine protection.
– Facial hair.
– Head and neck injuries.
Penetrating, blunt, expanding hematoma, active
bleeding
– Smoke inhalation.
Singed facial hair, soot, erythema, airway swelling
• Evaluate mental status and calculate GCS.
Diagnostic Tests
• If the patient is not protecting their airway or maintaining
their oxygen saturation, proceed to intubation before
© The Author(s), under exclusive license to Springer Nature Switzerland AG 2025
M. Neff et al. (eds.), Passing the General Surgery Oral Board Exam, https://doi.org/10.1007/978-3-031-78244-2_106
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356
A. Simmonds and S. Jinadasa
obtaining any diagnostic tests. If the patient is able to protect their airway and maintain their oxygen saturation,
proceed with the remainder of the trauma survey followed
by chest X-ray and any other indicated imaging.
Treatment
• If a patient requires intubation, rst ensure you have all
necessary staff and equipment required. Consider
obtaining:
– ED physician and/or anesthesiologist, respiratory
therapist
– Bag valve mask, oxygen, suction, various laryngo-
scope blades, video-assisted laryngoscopy, endotracheal tubes (ET tubes), ventilator, bougie, airway
adjuncts such as oropharyngeal or nasopharyngeal airway, stethoscope
– Monitors including blood pressure, heart rate, oxygen
saturation, and end-tidal CO
2
• After obtaining the appropriate equipment and staff, perform a rapid sequence intubation (RSI).
– Common induction medications include:
Etomidate—Short-acting hypnotic commonly used
in RSI.Fast onset and clearance, minimal hemodynamic compromise. May cause adrenal suppression. Common dose 0.3mg/kg IV
Ketamine—Sedative and anesthetic, commonly
used in children. May cause tachycardia and hypertension. May increase intracranial pressures.
Common dose 1–2mg/kg IV
Propofol—Hypnotic agent with rapid onset. Known
hemodynamic effects and should be avoided in
head injuries or hypotensive patients. Common
dose 1.5–3mg/kg IV
– Common paralytics include:
Succinylcholine—Depolarizing paralytic. Rapid
onset, short half-life. May cause hyperkalemia;
avoid in burns and crush injuries. Common dose
1.5mg/kg IV
Rocuronium—Nondepolarizing agent of choice if
succinylcholine is contraindicated. Has a longer
duration of action which may be a negative factor if
the patient is unable to be intubated. Common dose
1.0mg/kg IV
– Evaluate for signs of successful intubation, including
chest rise, bilateral breath sounds, fog in ET tube, and
end-tidal CO
.
2
– Make sure to get a follow-up chest X-ray to ensure
appropriate positioning of the ET tube.
Common Curveballs
• During your trauma assessment, patient decompensates:
restart the trauma evaluation with re-evaluating the
airway.
• Unable to intubate on rst pass: bag valve mask the
patient, use airway adjuncts, allow different provider to
try, obtain video-assisted laryngoscopy, and attempt with
bougie.
• Unable to intubate and patient unstable: proceed with surgical airway.
• Ongoing hypoxia after intubation: take out ET tube; bag
valve mask the patient; consider CXR, bronchoscopy, and
bilateral chest tubes.
• Difcult ventilation with bag valve masking: examine
mouth for foreign body; consider OPA or nasal trumpet.
• Burn patients: may appear comfortable on initial exam;
consider ber-optic laryngoscopy, and if erythema, soot,
or swelling is seen in oropharynx or hypopharynx, proceed with prophylactic intubation.
Clean Kills
• Failing to stop the trauma evaluation and return to the airway assessment when an airway problem is encountered
• Not re-evaluating the airway if the patient decompensates
at any time
• Not being prepared with adequate equipment and staff
• Not making a point to discuss cervical spine management
during intubation
Penetrating Trauma
What Questions May BeAsked?
“A 24-year-old man was standing outside of his home when
he was struck in the mandible by a bullet red from a passing
vehicle, thought to be from a small caliber handgun. He
presents with EMS sitting upright and leaning forward on
the stretcher. You note an obvious complete disruption of his
mandible with a large soft tissue defect that is causing signicant bleeding into his mouth. Saturations are 95% on 15
L via a blowby face mask.”
This patient sustained a projectile injury to the face that
resulted in severe oral trauma. He currently is maintaining
his oxygen saturation on a signicant amount of oxygen sup-
106 Emergency Airway
357
port. He has ongoing active bleeding which threatens his airway. He is instinctively sitting upright in an attempt to
maintain his airway, an important observation in the airway
evaluation.
History
• Obtaining history should be done quickly; sometimes it is
not possible to do so based on the acuity of the scenario.
• Determine antecedent events, such as mechanism of
trauma, intake of medications, and ingestion of
intoxicants.
• Determine if patient has required previous intubation and,
if so, if they had a difcult intubation.
Physical Exam
• Attempt to locate penetrating wounds. Consider all structures that may be injured such as the mandible, tongue,
hard or soft palate, facial bones, trachea, esophagus, or
carotid vessels.
• Identify areas of active bleeding which may be easily controlled with pressure or suture.
• Note any bubbling or drainage from wounds which may
signify aerodigestive involvement.
• If the patient is maintaining their airway, quickly evaluate
for other penetrating injuries and check their blood
pressure.
Cricothyroidotomy
• Equipment: scalpel, small-bore ET tube (5.0 mm or
6.0mm)
Steps:
• Use your nondominant hand to grasp the thyroid cartilage
and your nondominant index nger to identify the position of the cricothyroid membrane, just superior to the
cricoid cartilage (Fig.106.1).
• Make a generous vertical incision over the cricothyroid membrane with the scalpel, followed by a transverse incision through the cricothyroid membrane.
Place the handle of scalpel in cricothyrotomy and
rotate to dilate.
• Insert the endotracheal tube and inate the cuff.
• Evaluate for signs of successful intubation, including
chest rise, bilateral breath sounds, fog in ET tube, and
end-tidal CO2.
• Obtain a follow-up chest X-ray to ensure appropriate
positioning of the ET tube.
• Make sure to state that you will hold ET tube in place
until it is appropriately secured.
• Make sure to note need for converting to tracheostomy
within 24–48h.
Diagnostic Tests
• Avoid obtaining imaging in a patient with an anatomically
unstable airway until airway is secured.
Treatment
• Stable patient currently maintaining their airway and
oxygen saturation.
– Do not attempt to intubate the patient in the emergency
department.
– Make sure to pre-oxygenate.
– Move the patient to the operating room. Obtain two
anesthesiologists if available.
– In addition to previously listed equipment, obtain
ber-optic bronchoscope and prep for surgical airway.
– Ask anesthesia team to attempt awake intubation using
a ber-optic bronchoscope-assisted oropharyngeal or
nasopharyngeal intubation.
– If unable to successfully intubate or patient becomes
unstable at any time, perform cricothyroidotomy.
• Patient is unstable, or not maintaining their airway or
oxygen saturations.
– Consider a single attempt at traditional intubation. If
unsuccessful at rst attempt, poor visualization, or
severe anatomic distortion, proceed with
cricothyroidotomy.
Fig. 106.1 External anatomy of the airway
358
A. Simmonds and S. Jinadasa
Common Curveballs
• Patient decompensates because they have c-collar on that
is covering a penetrating injury and resultant expanding
hematoma in the neck that you missed because you didn’t
take off c-collar to examine the neck.
• Patient does not have bilateral breath sounds—if an ET
tube is used for the cricothyroidotomy, it may be advanced
too far into the left or right main stem bronchus. Make
sure to not advance the ET tube by more than ~7cm; if
you don’t have bilateral breath sounds, consider retracting
the ET tube.
• Pediatric patients have a larger occiput which increases
their neck exion and airway compromise. Place a shoulder roll to increase in-line positioning for intubation. The
cricothyroid membrane is signicantly smaller in children and emergent tracheostomy rather than cricothyrot-
omy should be pursued if unable to intubate.
Clean Kills
• Laying down a patient with upper airway compromise
before being ready to secure the airway
• Not identifying landmarks while performing the
cricothyroidotomy
• Not recognizing when the ET tube is not placed in
trachea
Airway Management inNon-trauma Patients
Angioedema
• Determine if patient has required previous intubation and,
if so, if they had a difcult intubation.
Physical Exam
• Evaluate the patient’s mouth and airway. Note any facial
edema as well as swelling of the lips or tongue that could
obstruct the airway.
Diagnostic Tests
• Avoid obtaining imaging in a patient with an anatomically
unstable airway until the airway is secured.
Treatment
• If patient is unable to maintain airway and is unable to be
intubated due to edema, proceed with surgical airway.
• Consider cricothyroidotomy as described above. If appropriate equipment or personnel are not able to be obtained,
consider needle cricothyroidotomy.
Needle Cricothyroidotomy
• Equipment: large-bore angiocatheter, 10 cc syringe,
saline, oxygen tubing (Fig.106.2)
Steps:
– Use your nondominant hand to grasp the thyroid carti-
lage and your index nger to identify the position of
the cricothyroid membrane, just superior to the cricoid
cartilage.
– Attach the angiocatheter to a 10cc syringe with 3–4cc
saline.
– Advance catheter through skin overlying the cricothy-
roid membrane, directing needle caudally at 45 degree
angle while continuously aspirating.
What Questions May BeAsked?
“A 60-year-old male presents to the emergency department
via EMS with rapid onset facial and tongue swelling after
starting a new blood pressure medication. Given his high
degree of tongue swelling, the emergency department is having a difcult time ventilating with bag valve mask or utilizing airway adjuncts. The patient is currently saturating 75%
and equipment for cricothyroidotomy is not immediately
available.”
This patient is experiencing angioedema, likely due to
recently starting an ACE inhibitor.
History
• Obtaining history should be done quickly; sometimes it
is not possible to do so based on the acuity of the
scenario.
• Determine antecedent events, such as mechanism of
trauma, intake of medications, and ingestion of
intoxicants.
Fig. 106.2 Needle cricothyroidotomy setup
106 Emergency Airway
359
– When air bubbles are identied, stabilize the needle
and advance the catheter until it is hubbed at the skin.
Remove the needle.
– Manually secure the catheter in place at all times.
– Connect catheter to oxygen tubing and bag valve mask
and proceed with ventilation.
– If appropriate tubing is not available, remove the
plunger from a 10cc syringe and connect to angiocath-
eter. A 6.0mm ET tube can be inserted into the syringe
and balloon inated and connected to BVM or ventila-
tor in the typical fashion.
– Jet ventilator may be utilized if available.
– Perform a denitive surgical airway as soon as equip-
ment is available.
Common Curveballs
• Patient has a modest increase in saturation but remains
unstable or is difcult to ventilate. Proceed with a denitive surgical airway when appropriate equipment is able
to be obtained. Needle cricothyroidotomy is not a denitive airway.
Clean Kills
• Continuing to attempt traditional intubation methods
when signicant upper airway edema is identied.
Proceed with surgical airway in this scenario.
• Failure of identifying proper landmarks when performing
needle cricothyroidotomy.
• Failure to indicate that needle cricothyroidotomy is not a
denitive airway.
Bibliography
Feliciano DV, Mattox KL, Moore EE, editors. Trauma. 9th ed.
NewYork: McGraw-Hill; 2021.
Hsiao J, Pacheco-Fowler V. Videos in clinical medicine.
Cricothyroidotomy. N Engl J Med. 2008;358(22):e25. https://doi.
org/10.1056/NEJMvcm0706755.
McKenna P, Desai NM, Tariq A, Morley EJ. Cricothyrotomy. In:
StatPearls. Treasure Island: StatPearls Publishing; 2024. http://
www.ncbi.nlm.nih.gov/books/NBK537350/. Accessed 2 Apr 2024.
Basics ofMechanical Ventilation
forthePracticing Surgeon
FrankJ.DiRoma andStephanieBonne
107
Concept
Mechanical ventilation (MV) is the delivery of positive pressure to the lungs via an endotracheal tube or tracheostomy.
Mechanical ventilation is indicated for respiratory failure,
which is dened as insufcient oxygenation (hypoxemia) or
insufcient alveolar ventilation (hypercarbia) or both.
Clinical indicators for MV are apnea; stridor; severely
depressed mental status (GCS<8); ail chest; and inability
to clear secretions and/or trauma to the mandible, larynx, or
trachea. Additional indications include failure to wean from
ventilator in the immediate postoperative period, respiratory
failure due to pneumonia, high spinal cord paralysis, diaphragmatic paralysis, and severe polytrauma.
Way aQuestion May BeAsked
A 35-year-old man was brought to the emergency department after being involved in a motor vehicle crash. He had a
severe chest contusion, subdural hematoma, femur fracture,
and grade V splenic laceration. The patient was taken emergently to the operating room for exploratory laparotomy and
splenectomy. He was left intubated postoperatively and
transferred to the SICU.He was seen by neurosurgery and
orthopedic service. He required 6units of blood, 6 units of
fresh frozen plasma, and 1 pack of platelets.
Over the next 24h, he began to desaturate and require
increased levels of FiO2. Original chest X-ray was unremarkable. Repeat chest X-ray showed uffy inltrates bilaterally.
Past medical history: smoker.
Physical exam: intubated male, BP 110.78, P 118, temp
38 02, Sa 93%. Signicant ndings on the physical exam
included numerous bruises and lacerations on hand and
abdomen and midline laparotomy incision.
F. J. DiRoma (*) · S. Bonne
Division of Trauma, Department of Surgery, Hackensack
University Medical Center, Hackensack, NJ, USA
e-mail: Frank.DiRoma@hmhn.org; stephanie.bonne@hmhn.org
Ventilator settings: TV 500, rate 14, PEEP 5, FiO2 100%
How toAnswer?
Differential diagnosis includes CHF, ARDS, pneumothorax,
pulmonary contusions, uid overload, pneumonia, and fat
emboli.
This question stems from ARDS. It might not be this
straightforward and give you bilateral inltrates and/or ventilatory settings pointing to ARDS.Ask for (as in the test
taker asks for the PE from the presenter) physical exam ndings and ABG results and ventilator settings+CXR ndings
will help differentiate the different diagnosis.
Acute Respiratory Distress Syndrome (ARDS)
• Caused by trauma, sepsis/infection, massive transfusion,
or a combination.
• Causes a decrease in lung compliance, making the lungs
stiff and difcult to inate; produces hypoxemic respira-
tory failure.
• Diagnosis—Berlin denition
– Onset within 1week of a known clinical insult or new
respiratory symptoms.
– Chest X-ray—bilateral opacities on chest imaging.
Remember to conrm ETT placement.
– Respiratory failure not fully explained by cardiac fail-
ure or volume overload.
ECHO needed in the absence of ARDS risk factors
– ABG—PaO2/FiO2 ratio in ARDS is less than 300.
Mild ARDS: PaO2/FiO2 200–300mmHg
Moderate ARDS: PaO2/FiO2 100–200mmHg
Severe ARDS: PaO2/FiO2 <100mmHg with a PEEP
>/= 5cm H2O
– ARDS can generate high peak pressures + plateau
pressure levels due to low lung compliance and high
airway resistance.
– Peak pressure—Dynamic pressure measured at the
end of inspiration evaluates the resistance to ow in
© The Author(s), under exclusive license to Springer Nature Switzerland AG 2025
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F. J. DiRoma and S. Bonne
the airways and the compliance of the lung and chest
wall. Continuously measured on the ventilator. Can’t
be lower than plateau pressure.
– Plateau pressure (pPlt) is measured at the end of
inspiration with a short breath-hold (inspiratory hold).
Static pressure. Measures the compliance of the lung/
pressure on alveoli.
Treatment Goals
Lung Protective Ventilation (P/F<300)
• Low tidal volume (TV) 4–6mL/kg of IBW
– TV—amount of air delivered with each breath
• High positive end-expiratory pressure
– PEEP—to recruit or stabilize lung units in hypoxic
patients. Initial setting usually 5–7cm/H2O. PEEP can
be increased by 2cm H2O every 10–15min as needed.
The initial goal is to reduce FiO2 levels <60% to avoid
oxygen toxicity.
• Plateau pressure </= 30cm H
O to avoid barotrauma
2
• pH >7.2 (permissive hypercapnia)
– Manipulate ventilator settings based on ABG
ndings.
– Respiratory rate x tidal volume = minute ventilation
(MV).
– MV affects the clearance of pCO2 from the
bloodstream.
– ↑ MV→↓ pCO2→↑ pH.
Proning (P/F<150)
• Can be used in patients with refractory hypoxemia
despite maximal ventilator settings.
• Recruits dependent lung zones.
• The patient should remain prone for 18–20h to yield
the most benet.
• ABG should be ordered after proning and just prior to
returning the patient to the supine position.
• Discontinuation of prone positioning is recommended
when the patient no longer shows a positive response
to the position change or mechanical ventilation support has been optimized.
Neuromuscular Blockade (P/F<150)
• Can be used in patients with refractory hypoxemia
despite maximal ventilator settings.
• Improves patient-ventilator synchrony.
• Decreases intrapulmonary shunting.
• Can cause residual weakness.
• Bispectral index monitor or peripheral nerve monitor
(train of four) is used to monitor the use of neuromuscular blocking agents.
Reverse I/E Ventilation/APRV
Inhaled Nitrous Oxide
• Improves hypoxia but not mortality
VV ECMO
• P/F<50mmHg 3+ h, P/F<80mmHg 6+ h
• pH<7.25
• PaCO2>60mmHg for more than 6+ h
Case Continuation The patient improves and needs to be
evaluated for extubation.
• Ventilator Weaning Criteria
– Risk assessment
Is the reason for extubation resolved or improved
enough that the patient can be safely extubated?
FiO2<50%, PEEP <8.
Patient protecting airway (follows commands,
cough, lift head).
Hemodynamically stable (HR<120, HR<110 w/o
increasing vasopressors).
Can the patient cough and clear secretions once
extubated?
– Spontaneous breathing trial (SBT)
Patient breathing on their own with minimal assistance from the ventilator.
SBT should be continued for 30min but no more
than 2h.
– Negative inspiratory force (NIF)
Patient needs to be able to follow commands in
order for test to be accurate.
Pressure measured on full inhalation.
−20cm H
O or greater (more negative), considered
2
successful.
– Rapid Shallow Breathing Index (RSBI)
Ratio of RR/TV.
Patients who cannot tolerate independent breathing
tend to breathe rapidly (high RR) and shallow (low
TV).
A RSBI of <105 is considered a good chance of
extubation success.
– Cuff leak—can be qualitative or quantitative
Performed to ensure there is no airway edema/
obstruction around the glottic structures of the neck
Qualitative—can auscultate the physical movement
of air around the ETT
Quantitative—about a 50% drop in TV seen on
mechanical ventilator considered to be a cuff leak
As air escapes around the ETT, decreasing the
tidal volume returned through the ETT tube to
the ventilator
If no cuff leak→steroids ×24h
– Most extubation failures occur within the 24–72h after
extubation.
Common Curveballs
• High plateau and high peak pressures
– Tense abdomen/ascites (tx—drainage)
– Pulmonary edema (tx—Lasix, drainage)