Emergency Medicine Curriculum Utilizing the Flipped Classroom Method: Pulmonary Emergencies

Author(s): Branditz, Lauren; King, Andrew; Kaide, Colin; Mitzman, Jennifer; Ostro, Benjamin; Martin, Daniel; Kman, Nicholas; Bahner, David; Werman, Howard; Thema, Tatiana; Barrie, Michael

e. Describe why mortality is higher in elderly patients with pneumonia. 2. Appendix B: Asthma and COPD a. Discuss the initial approach to management in patients with acute asthma and chronic obstructive pulmonary disease (COPD) exacerbations. b. Describe additional treatments for asthma/COPD exacerbations if the initial approach does not improve respiratory distress. c. Discuss considerations when utilizing noninvasive ventilation and intubation in patients with asthma and COPD. d. Describe the management of the intubated patient with acute asthma exacerbation. e. Discuss the role of asthma action plans and discharge regimens in preventing recurrent emergency department (ED) visits for pediatric acute asthma exacerbations. f. Discuss the role of antibiotics in patients with COPD exacerbation. Both educators and learners benefit from an interactive and collaborative classroom, leading to the creation and implementation of this proposed curricular model at our emergency medicine residency program. 11 This weekly small group curriculum has now replaced two hours of traditional lecture-based didactics. Learners divide into small groups, and a faculty facilitator guides each group session. Small groups are composed of a mix of junior and senior residents. This mix of learners allows those who are more senior to teach and mentor junior residents, while simultaneously expanding their own knowledge of topics via discussion with a faculty member. Since implementation, residents and educators are engaging in new, valuable flipped classroom learning communities at The Ohio State University Emergency Medicine Residency program. Through the curriculum, we continually seek to foster self-

Educational Strategies:
(See curriculum chart) Please refer to the curriculum chart of linked objectives and educational strategies.

Evaluation and Feedback:
This innovative curriculum was literature-based and specifically designed to maximize active learning using the flipped classroom learning model. We overcame initial challenges and skepticism from both educators and learners to execute a successful, novel curricular model. A survey was administered to each resident prior to initiation of the curricular innovation and repeated at the conclusion of the first 18-month cycle. Learners and educators were enthusiastic about the conference structure and expressed a preference for it rather than the previous, lecture-based didactics. More recently, during the second 18-month cycle of the flipped classroom curriculum, students were surveyed on their perceived quality of instruction of the various program components. A majority of residents (60.9%) reported that the small group discussions were good or excellent, compared to only 26% of residents who felt that our grand rounds sessions during the same time were good or excellent. This curriculum has been delivered to two cohorts of learners, delivering the content twice in three years to about 50 residents per cycle. On the most recent iteration, residents evaluated the teaching methods as effective, with an average rating of 4 out of 5 (4 being agree, 5 being strongly agree).
The curriculum is critically evaluated and updated by education faculty members in order to ensure educational material remains current and consistent with the emergency medicine core content.

Objectives
By the end of this small group session, the learner will be able to: 1. Define pneumonia and its diagnosis. 2. Understand the difference between community-acquired pneumonia (CAP), hospital-acquired pneumonia (HAP) and ventilator-associated pneumonia (VAP). 3. Identify common pathogens and unique features that may help with predicting a specific pathogen. 4. Discuss the risk factors for methicillin-resistant Staphylococcus aureus (MRSA) and Pseudomonas. 5. Describe why mortality is higher in elderly patients with pneumonia.

Case Studies
Case 1: A 25-year-old graduate student presents with a productive cough and fever that is getting worse. He has had a sore throat and a runny nose for 5 days, and also some ear pain. The cough started 2 days ago and he is bringing up green sputum. He has no other medical problems. Vital signs show a temperature (T) of 101°F and heart rate of 110 beats per minute, but normal respiratory rate, oxygen saturation, and blood pressure. Breath sounds are reduced on the left and chest radiograph (CXR) shows a left lower lobe infiltrate and a positive spine sign. c. This patient clinically fits a diagnosis of community-acquired pneumonia. The CXR confirms a lobar infiltrate. This should be treated with antibiotics. No further work up needs to be obtained. Remember, though, that pneumonia is a clinical diagnosis and not purely a radiographic diagnosis. Chest radiographs often lag behind the clinical course of pneumonia. Therefore, one should not depend on imaging findings to rule pneumonia in or out. Take vital signs, duration of illness, and physical exam into consideration when making this diagnosis and evaluating similar patients. 2. What are some associations between clinical presentations of pneumonia and specific pathogens?
a. Sudden onset with fever, rigors, pleuritic pain + rust colored sputum + lobar = Streptococcus pneumoniae (pneumococcus) b. Similar presentation to above but with "currant jelly sputum" = Klebsiella pneumoniae c. Causes of pneumonia in chronic obstructive pulmonary disease (COPD) patients = H.
influenza or Moraxella d. Pneumonia following influenza = pneumococcus or S. aureus e. Atypical pneumonia = Mycoplasma pneumoniae, Chlamydophila pneumoniae and Legionella f. Pneumonia with gastrointestinal (GI) symptoms = Legionella and other atypical organisms g. History of alcoholism and pneumonia = pneumococcus, oral anaerobes, Klebsiella and tuberculosis (TB) h. Recently on a cruise ship (past 2 weeks) = Legionella i. Aspiration = anaerobes such as Prevotella melaninogenica, Fusobacterium species, Peptostreptococcus species) and/or oral streptococci (eg, Streptococcus anginosus) 3. What imaging modalities are available to help diagnose pneumonia? a. Keep in mind that pneumonia is ultimately a clinical diagnosis -not an imaging diagnosis. Chest radiograph (CXR) is most commonly used, although sensitivity of CXR for visualization of pulmonary opacities is low at 43.5% with specificity of 93% 1 . In many studies, computed tomography (CT) imaging is considered the criterion reference to compare other imaging modalities. Thus, CT is considered a reasonable imaging option in patients with an unclear clinical diagnosis with equivocal plain film X-rays. b. Point-of-care ultrasound (POCUS) is an emerging imaging modality for early and reliable diagnosis of pneumonia, with a sensitivity of 88.5% and specificity of 91.6%. In the setting of lobar pneumonia, lung tissue on ultrasound appears similar to that of liver tissue. This is due to consolidation of the affected lung; the appearance is referred to as "hepatization" of the lung tissue. It is also possible to see air bronchograms. This refers to the fact that small airways, surrounded by consolidated lung parenchyma, can be visualized. If these air bronchograms are dynamic, with active bubbling through the air bronchograms, it is most specific for pneumonia. Static air bronchograms could be present in the setting of pulmonary consolidation due to atelectasis. c. A reasonable approach might be to get a CXR first and consider using CT when a patient's CXR is not clear (presence of other prominent abnormalities such as congestive heart failure (CHF), pleural effusions or other lung pathology) or there are very prominent symptoms or signs despite a fairly unremarkable CXR (ie, hypoxia). 4. Describe the tools to determine whether this patient should be admitted or discharged? The pneumonia severity index (PSI)/PORT score is a more complicated scoring scale for communityacquired pneumonia that accounts for a patient's age, comorbidities (for example: cancer, CHF, cerebrovascular disease, renal disease, liver disease) and clinical findings (confusion, tachycardia, tachypnea, hypotension, and abnormal temperature). The PSI score may be more accurate in terms of ability to identify patients who would benefit from placement in the ICU. However, it is much more complex, making it more difficult to memorize. Facilitators should encourage students to use online calculators or other applications to determine this score. 6. What are the most likely organisms and appropriate empiric antibiotics for this patient? a. In healthy young patients, pneumococcus and mycoplasma should be considered or a viral etiology such as influenza or respiratory syncytial virus (RSV). Legionella pneumoniae and H. influenza are less likely but possible organisms as well. b. This patient would have a very low score (0) by CURB-65 and PSI and qualifies for outpatient management: i. Outpatient uncomplicated pneumonia can be treated with: a macrolide (azithromycin or clarithromycin) or tetracycline (doxycycline). Recommended duration is generally 5 days. c. If there are other comorbidities such as chronic heart, lung, liver, or renal disease, diabetes mellitus, alcoholism, malignancies, asplenia, immunosuppressive conditions or use of immunosuppressive drugs, use of antimicrobials within the previous three months AND it is safe to send the patient home then consider: i. A beta lactam (augmentin, amoxicillin, or cefdinir) PLUS azithromycin or doxycycline.

DIDACTICS AND HANDS-ON CURRICULUM
ii. Consider monotherapy with a fluoroquinolone (levofloxacin or moxifloxacin). 1. As with all medications, beware potential side effects. Fluoroquinolones have been associated with risk of tendonitis, QT prolongation, aortic aneurysm/dissection.

Case 2:
A 66-year-old female presents from a nursing home for cough and fever for the past two days. She has been there since being discharged from the hospital two weeks ago for a CHF exacerbation. Paramedics note that her oxygen saturation was 84% on room air. She also has a history of diabetes type 2, hypertension, renal failure on dialysis, and has a chronic wound on her foot that is being treated with topical therapy and seems clean. She has no orthopnea and her last dialysis was today. Her vital signs show a saturation of 100% on four liters of oxygen, blood pressure is 180/100 mmHg, temperature is 101°F, and pulse is 108 beats per minute. Exam reveals clear mental status with some rales and decreased breath sounds in both lower lobes. There is no jugular venous distension or peripheral edema. Her labs reveal a minimally elevated lactate and a white count of 13 x 1000/mm 3 and a hemoglobin of 9.4 g/dL. Sodium and glucose are 134 mEq/L and 222 mg/dL respectively. Chest X-ray shows bilateral lower lobe infiltrates.

DIDACTICS AND HANDS-ON CURRICULUM
Question Prompts: 1. What are the differences between CAP, HAP, and VAP? a. Community-acquired pneumonia (CAP) -the infectious causes come from the community. b. Hospital-acquired pneumonia (HAP) not acquired while on the ventilator. This is essentially a pneumonia that occurs 48 hours or more after admission and did not appear to be incubating at the time of admission. c. Ventilator-associated pneumonia (VAP) is a type of HAP that develops more than 48 to 72 hours after endotracheal intubation.

Of those above, what is the diagnosis in this patient and how should this patient be treated?
a. Hospital-acquired pneumonia (HAP). b. CURB 65 = 2, and PSI of 136 or class V. 3. What are risk factors in this patient that should make the clinician broaden the coverage?
a. This patient has recent admission, nursing home patient, dialysis patient and chronic wound as risks for needing broader coverage. 4. Should HAP patients be treated with CAP coverage or broader coverage?
a. There seems to be an increasing amount of evidence that HAP patients admitted to the general wards and not to the ICU may be able to be treated with the same regimen as for CAP. b. Whereas patients admitted to the ICU or having many risk factors probably should receive broader coverage. c. The Infectious Diseases Society of America (IDSA) recommends each hospital regularly disseminate antibiograms and recommendations based on their local resistance patterns.
Case 3: A 55-year-old male renal transplant patient presents after being transferred from an outside hospital with possible bilateral pneumonia. He has a temperature of 99.9°F and was given intravenous (IV) azithromycin and transferred. He has a normal respiratory rate, oxygen saturation of 91%, and he is normotensive. His mental status is normal. He is coughing, feeling weak, and his CXR shows bilateral pneumonia versus pulmonary edema. He also has an acute kidney injury (AKI) with a blood urea nitrogen (BUN) and creatine (Cr) of 80 and 4.0, respectively (baseline Cr is 2.0). Glucose and sodium are normal. A chest CT is also performed without contrast and is interpreted as having evidence of necrotizing pneumonia. "Dirty dishwasher" appearance of pleural fluid (if obtained via thoracentesis) iv. Gross hemoptysis v.

DIDACTICS AND HANDS-ON CURRICULUM
History of MRSA skin lesions vi. Erythematous rash like toxic shock rash 1. Describe the risk factors for Pseudomonas pneumonia.
a. Bronchiectasis b. Structural lung disease (chronic bronchitis, COPD, emphysema, interstitial lung disease and restrictive lung disease) c. Repeated antibiotic use d. Long term steroids during the past 3 months Case 4: A 90-year-old female presents with mental status changes and seems delirious. The family says she is not making sense, cannot take care of herself, and in the past two days is getting weaker and more confused. She lives by herself but has had a home health nurse since she presented eight months ago with a urinary tract infection (UTI) and confusion. She is full code. She has a remote history of a myocardial infarction and a coronary artery bypass graft (CABG) 15 years ago. Now her temperature is 99°F, systolic blood pressure is 88, pulse oximetry is 90% on 4 liters of oxygen and her heart rate is 90 beats per minute. She only takes an aspirin and a beta blocker. She can follow simple commands but cannot answer orientation questions. Her mouth looks dry and she has poor skin turgor. She has decreased breath sound bilaterally and has mild diffuse abdominal tenderness  d-dimer, blood cultures, urine antigens, steroids, viral studies. a. Procalcitonin: Although elevated procalcitonin helps predict a bacterial infection over a viral etiology (depending on the cutoff used) it is not clear that ruling out a bacterial infection based on a low procalcitonin can be used to withhold antibiotics. Atypical bacteria may not show an elevation and similarly combinations of bacterial and viral infection may not show a rise in procalcitonin. Also, levels which can be initially low may elevate within several hours. It seems that its greatest value may be in limiting the duration of antibiotic therapy. 5 b. D-dimer: May predict a more benign course if low. However, it should be used judiciously because these patients are more likely to have an elevated d-dimer. Providers should decide prior to sending the test whether they plan to follow up with a computed tomography angiography pulmonary embolism protocol study for elevated d-dimer levels.
Consider the use of age-adjusted D-dimers. 6 c. Blood cultures: The IDSA recommends blood cultures and antigen testing in specific circumstances -ICU admission, cavitary infiltrates, leukopenia, active alcohol abuse, chronic severe liver disease, anatomic or functional asplenia, positive pneumococcal urine antigen, presence of pleural effusion. 7 d. Urine antigen testing for pneumococcus and legionella: These are more helpful than sputum and blood cultures with a sensitivity of nearly 40% to 50% compared to 10% of blood cultures. These tests can also be done within minutes. e. Steroids: Recent systematic review suggests that CAP patients who require hospitalization may benefit from corticosteroids (reduced mortality, need for mechanical ventilation, and hospital length of stay). However, the precise dose is not yet clear and studies have been small. A general approach can be to consider steroids in patients with septic shock refractory to vasopressors. Steroids are not a routine part of any pneumonia guidelines. 8 f. New on the horizon in the diagnosis and treatment of pneumonia: i. Use of swabs to detect multiple viral and atypical organisms. ii. Antivirals for respiratory viruses are being developed.

Objectives
By the end of this small group session, the learner will be able to: 1. Discuss the initial approach to management in patients with acute asthma and chronic obstructive pulmonary disease (COPD) exacerbations. 2. Describe additional treatments for asthma/COPD exacerbations if the initial approach does not improve respiratory distress.

Discuss considerations when utilizing non-invasive ventilation and intubation in patients with asthma
and COPD. 4. Describe the management of the intubated patient with acute asthma exacerbation. 5. Discuss the role of asthma action plans and discharge regimens in preventing recurrent emergency department (ED) visits for pediatric acute asthma exacerbations. 6. Discuss the role of antibiotics in patients with COPD exacerbation.

Case Studies
Case 1: A 25-year-old female with a history of severe asthma with many hospitalizations over the last few years presents for shortness of breath. Her respiratory rate (RR) is 24/min, oxygen saturation (O2sat) is 93% on room air and end tidal carbon dioxide capnography (ETCO2) is 40. On exam, she has diffuse expiratory wheezing.

Question Prompts:
1. What is your next step in management?
a. This patient presents with an acute asthma exacerbation. Albuterol (beta2 specific agonist) is the preferred initial starting agent. In an ED setting, nebulizer treatment is generally used over an inhaler, but delivery of medication via an inhaler with spacer is also effective (when done correctly, see more discussion in case 2 notes). Albuterol dosage depends on the severity of the asthma exacerbation, ranging from 2.5mg to 10mg. b. Levalbuterol (the levo-isomer) is more expensive and has no benefit over albuterol. 2 c. Salmeterol xinafaoate and formoterol are long-acting beta antagonists (LABAs), and they should NOT be used for acute exacerbations. 2. Discuss the role of non-invasive positive pressure ventilation (NIPPV) or bilevel positive airway pressure (BiPAP) in this asthmatic patient. a. Non-invasive positive-pressure ventilation will improve airflow → improve gas exchange → decrease work of breathing/fatigue → potentially reduce the need for intubation. b. Providers should move quickly to non-invasive ventilation if the patient is in respiratory distress and not immediately responsive to albuterol. Nebulized breathing treatments should be continued simultaneously with BiPAP. 3. Other than breathing treatments, what other medication should be given to all moderate/severe asthma exacerbations to improve airway inflammation? a. Steroids are indicated in all cases of moderate or severe asthma exacerbation. Generally oral and intravenous (IV) are equivalent, though IV administration may start to have effects slightly sooner than oral. b. The addition of ipratropium to albuterol may be additive and helpful in asthma exacerbations. Ipratropium is an anticholinergic agent that blocks the acetylcholinemediated muscarinic receptor-driven bronchoconstriction, leading to bronchodilation. 4. The patient does not initially respond to BiPAP and 5mg of nebulized albuterol. Describe an algorithm for status asthmaticus. a. Continuous nebulized albuterol. b. Magnesium: 1-2 grams IV over 10-30 minutes, although some suggest that it is more effective when given quickly. Tintinalli suggests 95 mg of MgSO4 in 4 divided doses, 20 minutes apart. A Cochrane review of the use of magnesium sulfate for treatment of asthma exacerbations in the emergency department describes improvement in peak expiratory flow rates and forced expiratory volume follow IV magnesium administration, but no change in admission rates. 3 c. Non-invasive positive-pressure ventilation: Start at inspiratory pressure of 10, expiratory pressure of 5 (10/5) and titrate carefully to watch for improvement. See this source for more information regarding the use of NIPPV in asthma. 4 d. Ketamine: Sub-dissociative doses of ketamine may help a patient to tolerate NIPPV and also help with bronchodilation by increasing circulating catecholamines. Also, in patients that are very agitated, fully dissociative ketamine can provide sedation while the team is able to initiate other treatments. e. Epinephrine: 0.3-0.5 mg intramuscular (IM). It can be given IV also in a carefully titrated, diluted fashion. i. Can mix an epinephrine infusion -take 1mg of epinephrine and add to 1 L of normal saline. Start the infusion at 1ml/min and titrate to effect. Max dose for adults is 20 mcg/min. ii. Can mix "push dose" epinephrine -take 1ml (1 mg/10 ml) from code epinephrine ampule and mix in 9ml of a saline flush. Dose is 1ml (0.1 mg) at a time every few minutes. iii. Be cautious with mixing push-dose or epinephrine drips, and do not do it if you are not comfortable with them because mathematical errors in mixing will often be 10or 100-fold and can be dangerous. f. Terbutaline acts on beta2 receptors to cause bronchial smooth muscle relaxation. It may also be considered for use in cases of severe asthma exacerbations. The recommended dose is 0.25 mg administered subcutaneously, and may be re-administered every 20 min for a maximum of 3 doses if necessary. Since they have a very similar mechanism, usually one gives either epinephrine or terbutaline. g. Heliox may be useful to help facilitate laminar flow in the narrowed airways. 5 5. Despite everything you have provided above your patient continues to decompensate. What is your next step? a. Intubation: When you intubate an asthmatic, be aware that breath stacking on the ventilator can lead to cardiopulmonary arrest. Intubation does not fix the asthma/bronchospasm; it just rests the patient. In asthma, the pressure is delivered to the small airways, not the alveoli, so expect peak airway pressure will be high. But unless there is a problem in the alveoli such as pneumonia or pulmonary edema, the plateau pressure should be normal. The goals of intubation include decreasing work of breathing, improving oxygenation and preventing barotrauma while waiting for the other therapies to work. i. Peak inspiratory pressure (PIP) is the highest level of pressure applied to the lungs during inhalation. In mechanical ventilation the number reflects a positive pressure in centimeters of water pressure (cm H2O). Peak inspiratory pressure increases with any airway resistance. Things that may increase PIP could be increased secretions, bronchospasm, biting down on ventilation tubing, and decreased lung compliance. ii. Plateau pressure (PPLAT) is the pressure applied to small airways and alveoli during positive-pressure mechanical ventilation. It is measured during an inspiratory pause on the mechanical ventilator. iii. Auto (Intrinsic) positive end-expiratory pressure (PEEP) results from incomplete expiration prior to the initiation of the next breath causes progressive air trapping (hyperinflation). This is called "breath stacking." This accumulation of air increases alveolar pressure at the end of expiration, which is referred to as auto-PEEP. Auto-PEEP = PPLAT -extrinsic PEEP (your vent settings). The risk of this can be decreased by prolonging the expiratory phase on the ventilator. b. Ventilator management tips in asthma i. Settings -Respiratory rate (RR) 10-12, Tidal volume (TV) 5-7mL/kg, minute ventilation <115mL/kg, inspiratory flow rate of 80L/min, PEEP 5, fraction of inspired oxygen (FiO2) at 100% and titrate down to keep oxygen saturation >90%. ii. Adjust ventilator settings to keep plateau pressure <30 and auto-PEEP <10. iii. Keep patient well sedated and potentially paralyzed to avoid fighting the vent. iv. Inspiratory flow rate may need to be increased to allow for a prolonged expiratory phase. v. Inspiration to expiration ratio (I:E) should be 1:3-1:5. This can first be accomplished by having a relatively low set respiratory rate and allowing for permissive hypercarbia. vi. If the patient does code on the ventilator, the first step should be to remove them from the ventilator circuit and allow for full exhalation, potentially actively compressing on the chest to fully exhale the patient. c. If despite all your efforts, you still can't oxygenate the patient, consider extracorporeal membrane oxygenation (ECMO).

Case 2:
A 2-year-old male with a history of eczema and several previous episodes of wheezing associated with colds presents to the ED. He has been previously well but today family noticed increased work of breathing. Vitals: heart rate (HR) 175, RR 45, SaO2 91% on room air, temperature (T) 98.8°F, blood pressure (BP) 110/80 mmHg. Patient is noted to have tight aeration, global retractions, nasal flaring and expiratory wheezing.
Question Prompts: 1. What is your next step? a. Short acting bronchodilators are the mainstay of therapy for acute asthma exacerbation in children. b. The addition of ipratropium bromide is efficacious in decreasing hospital admission when used with beta agonists. They do not demonstrate this effect when used alone and are also associated with significant cost as a single agent. The advantage is demonstrated more in patients with moderate to severe exacerbations at presentation. 6 2. What else can you give to help resolve the impending crisis? a. Early steroid administration is associated with decreased hospital admission. 7 This supports many large institutional practices of steroids in triage by standing order sets. There are multiple large studies which show decreased "bounce backs" when patients are discharged on steroids 8 although many of these studies included children and adults without breaking out the pediatric group separately. b. Route and specific steroid utilized is a topic of ongoing discussion and debate. In general, oral steroids have similar efficacy to IV steroids. Dexamethasone is a long-acting steroid with a half-life of approximately 50 hours, and has the added benefit of avoiding issues with medication compliance at home. c. Magnesium sulfate IV does demonstrate a reduction in hospital admissions particularly in those patients presenting with severe asthma. Nebulized magnesium does not demonstrate this outcome and currently is not recommended. 3. This patient improves dramatically with one nebulized albuterol-ipratropium and oral steroid.
When discharging the patient, what is important to confirm with the parents? a. Confirming or developing an asthma action plan can help to empower parents/patients to manage their asthma symptoms at home, encourage compliance with recommended interventions, and prevent return visits to the ED. b. The plans give patients exact instructions on what medications to take (such as when to start using daily inhaled steroids), how much to take, when to take them, and when to seek help. c. These plans generally provide a stepwise approach to asthma management. They should include: i. Descriptions of what to do in normal (asymptomatic) circumstances -for example, avoid asthma triggers, use daily controller medications. i. See Appendix A: Pneumonia for a discussion of risks of fluoroquinolones. c. Also consider antibiotics if there has been a change in sputum production from the patient's baseline with COPD exacerbation symptoms.

DIDACTICS AND HANDS-ON CURRICULUM
1. What is the most likely injury? Describe the pathophysiology that explains the patient's vital sign abnormalities. a. This patient is most likely suffering from a tension pneumothorax. b. The pathophysiology of traumatic pneumothorax is distinct from spontaneous pneumothorax. Blunt traumatic pneumothorax is caused by air entering the pleural space due to rib fracture with pleural penetration or from alveolar rupture due to sudden and forceful compression of the chest. c. When the patient inhales, air enters the pleural space through the injured alveoli or pleura.
If the air is not able to exit the pleural space on exhalation the air is trapped in the pleural space. In these cases, with each breath the intrathoracic pressure rises. As the intrathoracic pressure rises it can compress the mediastinum, thereby impairing preload and diastolic filling and ultimately leading to hemodynamic instability. If not treated immediately, it can progress to cardiac arrest. 3. What is the appropriate initial resuscitative measure in this patient? Describe the procedure. a. Immediate decompression with needle thoracostomy is indicated in this patient. b. The classically taught technique is to insert a 2.25 inch 14 or 16-gauge angiocatheter needle perpendicular to the chest wall at the 2 nd or 3 rd intercostal space, above the rib, in the midclavicular line. Then remove the needle leaving the angiocatheter in place to allow air to escape. c. Another technique involves inserting the needle in the anterior-axillary line at the 4 th or 5 th intercostal space -the similar location for chest tube insertion. d. See next questions for trouble shooting and placing the subsequent chest tube. 4. Your attempt at needle decompression is unsuccessful. What are the common pitfalls of this procedure and what are some ways to troubleshoot these issues? a. The most common pitfall of the classic needle thoracostomy procedure is that the standard 2.25-inch needle is not long enough to penetrate the pleural cavity. In order to successfully needle decompress obese patients a longer catheter is necessary. i. A meta-analysis found that a 2-inch catheter reached the pleural cavity in only 73% of patients, and a 2.52-inch catheter was required for a 95% successful rate. b. The chest wall is often actually least thick at the 5 th intercostal space at the anterior axillary line. If needle decompression at the midclavicular line is unsuccessful, consider attempting the procedure at the anterior axillary line. c. If needle decompression is still unsuccessful in an unstable patient, the next step is to perform emergent finger thoracostomy. Finger thoracostomy is performed identically to the first steps of a tube thoracostomy and can be performed rapidly and requires only a scalpel and hemostat. 5. The needle is finally successfully placed and the patient's vital signs stabilize. What is the most appropriate next course of action? a. After needle decompression, patients with traumatic tension pneumothorax require chest tube placement. b. Given the high incidence of concomitant hemothorax, pigtail catheters are generally avoided in traumatic pneumothorax. c. Traditionally, larger tubes (36F -40F) were used to help facilitate rapid drainage, drain blood, and prevent air leaks. However, a study in the Journal of Trauma and Acute Care Surgery recently compared the impact of small-bore chest tubes (28F -32F) to large-bore chest tubes (36F -40F). This study demonstrated no statistical difference in initial volume of blood drained, duration of chest tube placement, development of chest tube-related pneumonia and/or empyema, or persistent hemothorax. There was also no statistical difference in pain reported by patients at site of insertion. 4 d. In the polytrauma patient, resume advanced trauma life support (ATLS) protocol after the needle/finger thoracostomy to identify other injuries, and then place the chest tube during the secondary survey prior to computed tomography (CT) imaging. e. When appropriate, also consider local anesthesia with lidocaine, lidocaine with epinephrine, or sedation when placing a chest tube because this is a very painful procedure. If procedural a. This patient is suffering from a secondary spontaneous pneumothorax (SSP) in the setting of a COPD exacerbation. b. A secondary spontaneous pneumothorax is a pneumothorax that occurs as a complication of underlying lung disease. The most common cause of SSP is rupture of lung blebs in patients with COPD. The more severe the COPD the higher the risk of developing SSP. 1. Other lung pathologies that predispose patients to SSP include cystic fibrosis, lung malignancy (due to endobronchial obstruction with air trapping and tumor necrosis), necrotizing pneumonia (bacterial, Pneumocystis jirovecii, tuberculosis), and Marfan's syndrome. 2. How does secondary spontaneous pneumothorax differ from primary spontaneous pneumothorax? a. Unlike SSP, primary spontaneous pneumothorax (PSP) occurs without an inciting event and without underlying lung pathology. b. Patients with SSP are often more symptomatic presumably because these patients have poor pulmonary reserve due to underlying lung disease. c. Treatment options differ between SSP and PSP (see below). 3. What studies can you employ to evaluate a patient for a possible pneumothorax?

DIDACTICS AND HANDS-ON CURRICULUM
a. An upright CXR is usually the first imaging modality used when working up dyspnea in the emergency department. Visualizing the visceral pleural line that defines the interface of the lung and pleural air makes the diagnosis of pneumothorax. Point of care ultrasound and CT imaging are other imaging modalities which could be used. b. The diagnosis of SSP patients with COPD can be difficult for two reasons: 1. It may be difficult to visualize the visceral pleural line because the emphysematous lung is hyperlucent and there is minimal difference in radiodensity of the lung and air in the pleural space. 2. It may also be difficult to distinguish a thin walled bulla from the pneumothorax. As a general rule, the pleural line of a pneumothorax is convex whereas the pleural line of a bulla is concave relative to the chest wall. c. If the diagnosis of SSP is uncertain on CXR, CT of the chest is the gold standard diagnostic imaging modality and can define the presence, exact location, and size of the pneumothorax. Contrast is generally not necessary for the diagnosis of pneumothorax on CT. However, intravenous contrast is helpful in the evaluation of possible concomitant vascular thoracic injuries in cases of traumatic pneumothorax. 4. What is the most appropriate treatment for this patient? a. Supplemental oxygen: Treats hypoxia and helps facilitate absorption of air from the pleural space. In patients with COPD, however, hyperoxia should be avoided. b. Pleural drainage: In general, there are three options for treatment of any spontaneous pneumothorax without tension physiology: observation with supplemental oxygen, needle aspiration, and tube thoracostomy. Patients with SSP have underlying pulmonary disease such as COPD which make the likelihood of persistent air leak higher and are at high risk for further expansion of the pneumothorax. Thus, unlike the treatment of stable spontaneous primary pneumothorax (see below), all but the smallest SSP require pleural drainage. 1. Patients who are minimally symptomatic with a very small pneumothorax (<1cm between the visceral and parietal pleura at the level of the hilum on CXR) may be treated with supplemental oxygen and observed for 12 -24 hours with frequent clinical reassessments and repeat CXR to monitor for expansion of the pneumothorax. 2. For all other SSPs, tube thoracostomy is preferred to needle aspiration due to the high risk of persistent air leak and pneumothorax expansion. 5. What are the benefits and possible risks of placing a pigtail catheter over a large bore tube? a. Studies comparing small bore (10F -14F) and large bore (24F -28F) chest tubes for drainage of SSP are all retrospective, and thus lower quality evidence. However, the available research seems to indicate that placement of small-bore chest tubes is non-inferior to the placement of large bore tubes. There does not appear to be any difference in rate of successful placement, length of hospital stay, recurrence rate, and complications. Anecdotally, and as one might expect, patients seem to tolerate placement of pigtail catheters better than large bore tubes. b. Traditionally, large bore tubes have been used to drain SSPs in patients who are intubated due to concerns that smaller tubes may not be adequate to drain large air volumes experienced during positive pressure ventilation. This is controversial and the decision should be made in conjunction with the surgical/critical care teams that will be assuming care of the patient. 6. You've successfully placed your chest tube and now wonder what to do with the free end of the tube. What are your options? What are the pros and cons of each? Suction or no suction? a. The two options are an underwater seal drainage device (ie, Pleur-evac) or a unidirectional flutter valve (ie, Heimlich valve). Both devices contain a valve mechanism that allows air to exit without allowing entry of air from the outside on inhalation. The underwater device has the benefit of allowing the physician to visualize and even quantify air leaks which may help guide further management. These devices are also readily attached to suction when/if needed. The Heimlich valve has the benefit of allowing the patient to be mobile. The decision can be made on a case-by-case basis considering patient preference and the wishes of the admitting team. b. Suction should not initially be used for management of tubes placed for SSP due to the increased risk of re-expansion pulmonary edema. Suction may be used if the pneumothorax does not resolve. Suction is applied using a high-volume, low-pressure system with pressures of -10 to -20 cm H2O.

Case 3:
A 20-year-old male with a one pack-per-day smoking history presents with left-sided chest pain. Other than his tobacco use he has no medical problems. He states that he was sitting on his couch watching television when he developed a sudden onset of pleuritic pain over the left side of his chest associated with mild dyspnea. He denies recent trauma or any other obvious precipitating factors. He has never experienced this pain before. He has no cardiac or pulmonary embolism risk factors. His vitals are BP 120/80 mmHg, HR 70/min, RR 14/min, O2sat 97% on RA, and T 98.6°F. He has diminished breath sounds on the left but otherwise no focal exam findings. The chest radiograph shows a left-sided pneumothorax. 1. Compared to the patient in Case 2, how would you classify this patient's pneumothorax? What is the incidence and possible risk factors for this disease process? a. Because there is no underlying pulmonary disease, the pneumothorax would be classified as a primary spontaneous pneumothorax. In contrast, the patient in Case 2 has severe underlying COPD making the pneumothorax secondary spontaneous. b. The incidence of PSP in the US is 7.4 cases per 100,000 population per year in men and 1.2 cases per 100,000 per population per year in women. The reason for the strong male predominance is unknown. Interestingly, the incidence of PSP in the UK is 5x higher in men and 12.5x higher in women than in the US. c. Cigarette smoking is the most significant risk factor for PSP. In a study that reviewed four articles, 91% of patients diagnosed with PSP were cigarette smokers. The incidence of PSP is also directly proportional to the amount of cigarette smoking. Other risk factors include family history, tall stature, thoracic endometriosis, and anorexia nervosa. 2. What are the treatment options for this patient? How do they differ from the patient in Case 2? a. The initial treatment options for patients with PSP include observation and supplemental oxygen, needle aspiration, and tube thoracostomy. The choice depends on patient characteristics and clinical circumstances. Unlike SSP, patients with PSP are more often candidates for observation or needle aspiration rather than tube thoracostomy due to a much lower rate of persistent air leak and recurrence. b. Small pneumothorax (<2 -3cm) and minimally symptomatic: These patients are candidates for supplemental oxygen and observation. If after 6 hours of observation their symptoms have not progressed and repeat CXR shows stable or improving pneumothorax, these patients may be discharged with strict return precautions. c. Larger pneumothorax (>3cm) or significant symptoms: These patients should undergo needle aspiration. Needle aspiration is performed using a thoracentesis kit. Using CXR or ultrasound to identify the air pocket the catheter is inserted and air is manually withdrawn until no more air can be aspirated. A persistent air leak is presumed if there is still no resistance after aspirating 4L of air. At this time a small-bore chest tube should be placed. d. If aspiration is successful you can proceed one of two ways:

DIDACTICS AND HANDS-ON CURRICULUM
1. The catheter is left in place and a stopcock is attached to the free end and the tube secured to the chest wall. The patient is observed for four hours at which time a chest x ray is obtained. If the lung remains expanded the catheter may be removed and observed for an additional two hours. If a repeat chest x ray shows no recurrence the patient can be discharged home. 2. The catheter is left in place and attached to a Heimlich valve and the patient is discharged home with 48-hour follow up. e. Aspiration is preferred over tube thoracostomy in management of PSP. Aspiration has been shown to have similar outcomes to tube thoracostomy with the benefit of limiting admissions and hospital length of stay.