Holy smokes! Inhalation Injury

First steps (stable pt)
-treat as a trauma pt (ABCDE) and look for traumatic injuries
-place pt on NRB with O2 to 15 L/m
—add nebs 4% lidocaine early to prepare for visualization of cords with videolargynoscope
–4:2:1 rule for burn pt fluid resuscitation
—give fluids even if no external burns visible, as pt will have insensible losses
-treat pain!
-evaluate cords and surrounding laryngeal structures for edema with video laryngoscope or bronch

How to risk-stratify your patient with suspected smoke inhalation injury:

Rule out
–carbon monoxide toxicity: obtain serial blood gases (send co-oximetry) to monitor carboxyHb. Normal levels are 5 – 12%, depending on whether or not the pt is a smoker. Also consider if family presents with similar vague symptoms.
-cyanide toxicity: cyanide levels are not reliable in excluding toxicity, as it is rapidly cleared, and don’t result for days. Use lactate>8 or rising lactate despite fluid resuscitation to raise suspicion for toxicity
—ddx for elevated lactate (=impaired tissue oxygenation) in burn pt: cyanide, metHb, hypoxia, volume depletion
-look for rhabdo and AKI

Warning signs of respiratory failure
–drooling or difficulty swallowing = impending failure
-monitor for stridor, hoarseness, and respiratory distress
-PaO2/FiO2 ratio indicates degree of pulmonary shunting past injured lung. PaO2/FiO2<300 forewarns respiratory failure

Intubation
-early elective intubation in a controlled setting is better than crash intubation of a pt with edematous airway structures
-Prepare multiple sizes ETTs in anticipation of vocal cord edema. Use the largest that will fit so that the pt can get a bronchoscopy upstairs. Prepare suction for soot-filled secretions. Sux is safe to use up to 24h post-burn.
-use volume controlled ARDS settings (6-8 mL/kg TV)
—airways and lung become less compliant in inhalational injury, so must prevent barotrauma and allow for permissive hypercapnea

Blunt Cardiac Injury Guidelines

To trop or not to trop? Here's a brief review of the 2012 EAST trauma guidelines for BCI. 

What is BCI, anyway?

Describes a range of injuries due to blunt thoracic trauma: wall motion abnormalities, myocardial contusion, valve injuries, focal wall dilation, coronary injury, pericardial rupture, wall rupture

Right heart most commonly affected as it is most anterior.

Who to work up?

According to 2012 East guidelines: “patients with any significant blunt trauma toanterior chest should be screened.”

Also consider BCI in patients with persistent unexplained tachycardia, cardiogenic shock, or hypotension not explained by other injuries.

Now that I suspect BCI, what should I do?

Screening:

Screening consists of an EKG (Level 1 evidence) and a troponin (Level 3 evidence). Early studies suggested that EKG alone is sufficient to diagnose BCI, however multiple studies since then show that such an approach does not capture the small percentage of BCI patients that present with normal initial EKG and positive troponin. 

A normal EKG and troponin rules out BCI (even in the setting of a sternal fracture, which is not predictive of BCI). Several studies show that the addition of troponin raises the NPV to 100%. Same screening approach is supported for pediatric pts.

Management & Disposition: 

Management is supportive; severe trauma may require surgical repair. 

Patients who have a new abnormality on EKG (arrhythmias, ST changes, heart block, PACs or PVCs, ischemic changes, etc) must be admitted to a telemetry floor for continuous monitoring. 

A new dysrhythmia or hemodynamic instability warrants an echo, preferably TEE over TTE.

Note that degree or persistence of elevation of troponin does not correlate with prognosis.

The chicken or the egg…did an MI precede the MVA or is it BCI?

It is important to differentiate which patients need cath with anticoagulation and which patients would be harmed from it. Can be differentiated via ekg-gated CT angiocoronaries.

Read more at:
http://www.aast.org/blunt-cardiac-injury
https://www.east.org/mobile/practice-management-guideline/96

Traumatic Hemothorax

Case: 18 y/o M is wheeled in with a stab wound to the left chest. VS: HR 130, BP 95/45, RR 30, SpO2 92% on 15L NRB. Pt is maintaining airway, no tracheal deviation, diminished BS on the left, strong distal pulses. You place a left-sided 36F chest tube with immediate blood return. 

What are the possible etiologies of traumatic hemothorax?

Laceration/injury to the heart, major vessels, intercostal vessels, mammary arteries, thoracic spine, diaphragm or lung parenchyma. 

How reliable is the FAST exam in diagnosing a hemothorax?

Sensitivity is 92-96% however bear in mind that the presence of subcutaneous air or concomitant PTX may obscure the underlying blood.

How much blood must be present to diagnose a hemothorax on CXR?
For upright CXRs, 150-300mL of blood causes blunting of the costophrenic angle. However, most trauma will have their CXR done in a supine position, which has a low sensitivity 35-60%. It may take 1L of blood distributed throughout a supine hemithorax to develop haziness on a supine film!

What defines a massive hemothorax?
Traditionally:

-Immediate drainage of 1.5L (or 15mL/kg) or 1/3 of blood volume
-Drainage of 200mL/h (or 3mL/kg/h) x 2-4 hours plus persistent need for blood products

Other definitions:

How to manage a massive hemothorax post thoracentesis?

Address hypoxia by keeping patient on oxygen and may attempt to position so that affected lung is down (if permitted by lack of other injuries). Resuscitate with 1:1:1 blood products. These patients benefit from thoracotomy in the OR as soon as possible. 

What are the long-term complications of not adequately draining a hemothorax?

Retained hemothorax consisting of clotted blood can form, which is not easily drainable by a chest tube. A traumatic hemothorax is also a nidus of infection; these patients are at risk of developing empyemas.