UMEM Educational Pearls - Airway Management

Aortoenteric Fistula (AEF)-Beware the Upper GI Bleed!

Important points about AEF:

• Most of the time this is a complication of AAA repair (secondary fistula)
• Fistula site normally in the duodenum (the graft erodes into the duodenum)
• "Herald bleed" seen in 20-80% of patients (bleeding stops spontaneously then stops prior to massive hemorrhage)
• Diagnostic studies frequently waste too much time. As a rule of thumb, any unstable patient with a history of AAA repair who presents with a massive GI bleed should probably be taken to the OR for emergent laparotomy. Stable patients may need to get a CT scan and/or EGD (although EGD misses many of these)
• Failure to consider the diagnosis (and act) may lead to bad patient outcomes
• Have a low threshold to call a gastroenterologist AND a surgeon when this diagnosis is being entertained. If you are wrong and it isn't an AEF, no big deal. But if you are correct, you may have saved a life!

Pearl: Suspect a aortoenteric fistula in any patient with a prior AAA repair who presents with an upper GI bleed (may also be lower GI bleed)

The French Surgeon Rene Le Fort first described these facial fracture patterns.   Reportedly he made the observations after dropping numerous skulls from the wall of a castle.  This might be why we don't see pure Le Fort fractures in our patients most of the time as they are not likely to be falling off castle falls head first.

The classic fracture patterns are:

1. Le Fort I fractures extends from the nasal septum to the lateral pyriform rims, travels horizontally above the teeth apices, crosses below the zygomaticomaxillary junction, and traverses the pterygomaxillary junction to interrupt the pterygoid plates.
2. Le Fort II fracture has a pyramidal shape and extends from the nasal bridge at or below the nasofrontal suture through the frontal processes of the maxilla, inferolaterally through the lacrimal bones and inferior orbital floor and rim through or near the inferior orbital foramen, and inferiorly through the anterior wall of the maxillary sinus; it then travels under the zygoma, across the pterygomaxillary fissure, and through the pterygoid plates.
3. Le Fort III fractures (transverse) are otherwise known as craniofacial dissociation and involve the zygomatic arch.  These fractures start at the nasofrontal and frontomaxillary sutures and extend posteriorly along the medial wall of the orbit through the nasolacrimal groove and ethmoid bones. The fracture continues along the floor of the orbit along the inferior orbital fissure and continues superolaterally through the lateral orbital wall, through the zygomaticofrontal junction and the zygomatic arch.

 

http://radiographics.rsnajnls.org/cgi/content-nw/full/26/3/783/F15

Keys to a Successful Intubation

• Use both hands-bimanual laryngoscopy should be a routine part of ED intubations.
• Don't forget that you CAN let up cricoid pressure-this can actually obscure your view and make your job more difficult.
• For obese patients, make sure you elevate them. You want their ear level with their sternal notch. This might require A LOT of pillows or towels.
• Use a "straight-to-cuff" technique for stylet shaping. This is accomplished by making the stylet straight down to the cuff and then making a 15-20 degree bend at the cuff.

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Brugada syndrome ECG findings are now well-recognized by many emergency physicians, but we need to be aware of mimics as well. Conditions that have been reported to induce a Brugada-ECG pattern include hyperkalemia, hypercalcemia, cocaine intoxication, and conditions that impinge on the right ventricle (e.g., tumors, pericardial fluid). There's debate in the cardiology community regarding how to manage these patients...but this debate is best left to your cardiology consultants. When you see a Brugada-like finding, get an electrophysiologist involved in the case!

To echo Dr. Rogers' fantastic airway tips:

When considering an intubation or managing an emergent respiratory concern, keep the "P"s of intubation in mind:

1. P osition:  No intubating on the floor!  Don't get sucked into the patient's oropharynx! Maintain an appropriate distance. Align the airway axes. Sniffing position is utilized for non traumatic adult airways; this involves flexion of the lower c-spine and a bit of extension at the upper cervical levels. Take off cervical collars. Use pillows / blankets to align the external auditory canal (EAC) with the sternal notch to help w/visualization. Cricoid pressure is NOT designed to facilitate passage of the ETT- it MAY help prevent excessive gastric insufflation.

2. P reparation: Two tubes. Two blades. Two intubators. Plan B(ougie) or Plan C(cric). Though your emergency airway plans may differ, think of ALL airways as potentially difficult ones. Respect the epiglottis. 

3. P reoxygenation: 100% via NRBM when possible to ensure oxygenation and nitrogen washout. In patinets with at least some reserve, this will help to avoid pulse ox pitfalls. True RSI does NOT involve positive pressure ventilation.

4. P remedication: Know your sedatives in advance. Etomidate ? Ketamine ? Diprivan ? Whatever your agent of choice, know indications and drug dosages. Emergent RSI is a less than ideal time to access Epocrates.

5. P aralysis:  This is pretty much the point of no return. Administration of paralytics commits you to securing a patient's airway. Both rocuronium and succynylcholine can be dosed at 1 mg/kg IV.

6. P ass the tube: What Dr. Rogers said.

7. P osition confirmation: Direct visualization of the tube through the glottic opening coupled with end tidal Co2 is ideal.

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 Quick Pearls for Intubating:

1. When intubating, make sure to use two hands!

• Have the person holding cricoid pressure let up...cricoid pressure many times makes your job more difficult
• You as the intubator then swing your right hand around and manipulate the larynx (left, right, up, down, etc)
• When you get the view you want, have someone take over pressure and then pass the tube
• Using two hands makes your job so much easier

2. Resist the urge to look for cords

• Your job is to get the tube in the airway
• If you can identify the two arytenoid cartilages, you are home free. Aim north of these structures.
• You don't have to see cords to intubate. All you need are the landmarks that identify the entry into the glottis....just pass the tube north!
• I had a case just a few days ago where the only thing we saw were the two arytenoids (covered in blood). No cords were seen, but we passed the tube above (i.e. north) the arytenoids and we were in.

3. Stylet shape is crucial

• Shape your tube with the "straight to cuff" technique
• The tube is straight and then bent 15-20 degrees at the beginning of the cuff
• This shape will prevent the tube from actually obscuring your view and will increase your success.

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 Pregnancy and Acute Pulmonary Embolism

Women who are pregnant or in the postpartum period and women who take hormonal therapy are at an increased risk of pulmonary embolism.

Some facts:

• Risk of first episode of venous thromboembolism is 15 times as high in the postpartum period as during pregnancy
• Diagnostic workup and initial ED therapy is the same as it is for non-pregnant patients
• Although there are still some concerns about pulmonary CTA, both the American College of Obstetrics & Gynecology and the American College of Radiology agree that it is safe. It is unknown what happens to fetal nephrons after exposure to circulating contrast in the mother. Despite this, CTA can be used without fear if indicated. 
• Warfarin is a teratogen and should not be used for anticoagulation.

 

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 Thrombolytic Therapy for PE

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Care of the Crashing Asthma Patient

Several things should be considered in the crashing asthmatic:

• First and foremost, there is very little date on how to manage the crashing asthmatic!
• Any sick asthma patient should have IV fluid replacement-these patients have tons of insensible losses. IV fluids may also help with post-intubation hypotension cause by compression of the vena cava.
• Many EM folks have left Ketamine in the dust for intubating an asthmatic....anecdotally, it works, but creates very sticky and tenacious lung boogers that are hard to suction. Why make your job even harder?
• Sounds like common sense, but RSI the patient in the position of comfort (usually tripod) and then quickly lay them back supine.
• Consider instituting the "kitchen sink approach" to asthma care. This includes beta agonists, anticholinergics, Mg, steroids, IVF, epi, nebulized Lidocaine, perhaps non-invasive ventilation, inhaled (yes, inhaled) steriods. Our job really begins once they have been tubed.
• Sounds corny, but consider a "bedside coach." Believe it or not, some really sick asthmatics can be talked through a severe, life-threatening exacerbation. This can be a nurse, tech, physician. Someone to talk to them during this crisis. It works sometimes.
• Any intubated asthmatic who goes into PEA arrest should not be declared dead unless bilateral needle decompressions and bilateral chest tubes have been performed.
• If an intubated asthmatic codes once intubated, consider the following: (1) disconnect from the ventilator and bag VERY slowly...4-6 breaths/minute or even slower! (2) Although controversial, some consider manual chest wall compression helpful in "getting rid" of trapped air. (3) Vigorous IVF-positive pressure ventilation worsens the patients hyperinflation which compresses the vena cava, and (4) consider needle decompression and then chest tube insertion

According to ACEP's clinical policy, a non-contrast head CT is only indicated in mild traumatic brain injury under the following circumstances:  

1)  headache
2)  vomiting
3)  age over 60
4)  drug or alcohol intoxication
5)  short-term memory deficits
6)  physical evidence of injury above the clavicle
7)  seizure

Bougie-Facilitated Intubation Using the Bougie as a rescue device can sometimes be complicated with difficulty advancing the endotracheal tube as the tip can get hang up at the level of the glottis. Two things that can help advance the tube: Rotate the tube 90 degrees counterclockwise. Stop holding Cricoid Pressure, especially in female patients A recent study looking at cricoid pressure showed that the frequency of impingement was 38% with sham pressure and 60% with true cricoid pressure. This statistically significant difference was entirely attributable to an effect in female patients. Original Article: McNelis U et al. The effect of cricoid pressure on intubation facilitated by the gum elastic bougie. Anaesthesia 2007 May; 62:456-9. Forget about Sterile Saline and Use Tap Water Irrigation In a multicenter prospective trial of 715 patients, Moscati et al have shown that rates of wound infection were similar (3.3% compared to 4.0%) in patients that received clinician-administered sterile saline irrigation or at least 2 minutes of self-administered tap-water irrigation. The amount (volume) of irrigation is more important than whether the irrigate is sterile or not. Moscati RM et al. A multicenter comparison of tap water versus sterile saline for wound irrigation. Acad Emerg Med 2007 May; 14:404-9.

1. Hyperventilation in the pediatric HI causes an increase in cerebral ischemiaand increases in ICP 2. Cuffed tubes can be used in the pediatric airway 3. The most common cause of bradycardia in pediatric RSI is hypoxia and this is NOT prevented with atropine 4. Patients with an underlining neuromyopathy have an upregulation of neuroreceptors (they actually have more in number) the risk if hyperkalemic cardiac arrest is significant if succynlcholine is administered. 5. During Direct Laryngoscopy; the Mac blade can also be used as a Miller negating changing the blades. 6. Intubation is now a bimanual procedure as the use of External Laryngeal Movement (ELM) significantly increase the intubators view.

1. 30% of all ETT placed in the field by EMS are esophageal. 2. Patients that will rapidly desaturate - think "POPS" ie Pregnancy, Obesity, Pediatric, Smoke inhalation. 3. In the adult the only absolute contraindication to performing a cricothyroidotomy is a fractured larynx. 4. Post intubation desaturation think "DOPE" ie Displacement, Obstruction, PNTX, Equipment failure.

Use plateau pressure, rather than peak inspiratory pressure, as a means of assessing the risk of barotrauma * One mechanism (of many) by which mechanical ventilation can induce acute lung injury in patients with ARDS is overdistention of the alveoli * 2 common parameters used to assess airway pressures are plateau pressure (Pplat) and peak inspiratory pressure (PIP) * Pplat approximates small airway and alveolar pressures more closely than PIP * ARDSnet trial demonstrated a reduction in the number of ventilator days and mortality when Pplat was maintained < 30 cm H2O. References: 1. ARDS Network. Ventilation with lower tidal volumes as compared with traditional tidal volumes for acute lung injury and the acute respiratory distress syndrome. NEJM 2000;342:1301-8. 2. Marcucci L, ed. Avoiding common ICU errors. Philadelphia; Lippincott Williams & Wilkins; 2007:275-6.

Recognize the signs of venous air embolism when inserting a central venous catheter * Although rare, a feared complications of CVC insertion is venous air embolism (VAE) * Conditions that increase the risk of VAE are detachment of catheter connections, failure to occlude the needle hub during insertion, hypovolemia, and upright positioning of the patient * Clinically, VAE presents with acute dyspnea, cough, chest pain, altered mental status, tachypnea, tachycardia, and/or hypotension * Treatment includes placing the patient in a left lateral decubitus position, reverse Trendelenburg, and providing 100% oxygen via NRB * Also consider hyperbaric oxygen therapy * Aspiration of air, as recommended in some textbooks, is rarely successful Reference: Mirski MA. Lele AV. Fitzsimmons L. Toung TJ. Diagnosis and treatment of vascular air embolism. Anesthesiology 2007;106(1):164-77.

During rapid sequence intubation (RSI) we endeavor to avoid positive pressure ventilation, prior to securing a definitive airway. As such, an adequate buffer of oxygen is necessary to ensure a safe apneic period. This process involves replacing the residual nitrogen in the lung with oxygen. It has been demonstrated that a standard nonrebreather (NRB) mask alone does not provide a high enough fractional concentration of oxygen (FiO2) to optimally denitrogenate the lungs (1). Even when a nasal cannula at 15L/min is utilized in addition to the NRB, the resulting FiO2 is not ideal. A bag-valve mask (BVM) with a one-way-valve or PEEP valve has been demonstrated to provide oxygen concentrations close to that of an anesthesia circuit. But its effectiveness is drastically reduced if a proper mask seal is not maintained during the entire pre-oxygenation period (1). This is not always logistically possible in the chaos of an Emergency Department intubation.

A standard NRB with the addition of flush-rate oxygen appears to be a viable alternative. Recently published in Annals of Emergency Medicine, Driver et al demonstrated that a NRB with wall oxygen flow rates increased to maximum levels, rather than the standard 15L/min, provided end-tidal O2 (ET-O2) levels similar to an anesthesia circuit (2). 

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