The Daily Differential — Tuesday, July 28, 2026

Pneumomediastinum

Most spontaneous cases are benign, but missed esophageal or tracheobronchial injury can progress rapidly to mediastinitis, sepsis, and death. The management fork is not “air present or absent”; it is whether a structural source is leaking into the mediastinum.

By the Blue Fish Med Desk Jul 28, 2026 · Phoenix

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A 22-year-old man arrives clutching his upper chest after an evening of forceful retching, his voice strained and his neck tender beneath the fingertips. He is anxious but speaking in full sentences; a faint crackling sensation is palpable above his clavicles. Oxygen saturation is 98% on room air, and the first chest film shows streaks of lucency where they should not be. The question is whether this is a self-limited escape of air—or the surface clue to a perforated esophagus.

— What’s your move? Read on.

Before you read

When does the patient need CT, contrast esophagram, antibiotics, or surgery?
What must be excluded before calling this “spontaneous”?

When to Think of It

Think of pneumomediastinum with acute chest, neck, or throat pain; dyspnea; odynophagia or dysphagia; subcutaneous emphysema; voice change; Hamman sign; or unexplained mediastinal air on imaging. Common settings include forceful vomiting, coughing, asthma, inhalational drug use, childbirth, blunt or penetrating trauma, recent instrumentation, and positive-pressure ventilation.

Sick or Not Sick

Sick patients have shock, fever, toxicity, severe respiratory distress, peritonitis, rapidly progressive subcutaneous emphysema, pleural effusion or pneumothorax, or a high-risk mechanism such as vomiting, trauma, or instrumentation. The single call that matters most is: Is there an aerodigestive tract perforation requiring urgent source control?

The First Fifteen Minutes

ABCs, cardiac monitoring, two IVs, analgesia, and upright chest radiography; obtain CBC, CMP, lactate, blood gas if ill, and type and screen if perforation is plausible.
If hypoxemic → oxygen by nasal cannula 2–6 L/min or nonrebreather 10–15 L/min, because increasing inspired oxygen accelerates nitrogen washout from extravascular air.
If moderate-to-severe pain → fentanyl 25–50 mcg IV, repeat 25–50 mcg every 5 minutes to effect, because μ-opioid analgesia reduces pain-driven splinting; monitor ventilation.
If nausea or retching → ondansetron 4 mg IV/IM, because stopping further emesis limits additional pressure injury.
If shock or suspected perforation with sepsis → balanced crystalloid 500–1,000 mL IV bolus, reassessing after each bolus, because restoring preload supports perfusion while source control is arranged.
If esophageal or airway perforation is strongly suspected → piperacillin-tazobactam 4.5 g IV now, because it covers enteric gram-negatives and anaerobes; add vancomycin 15–20 mg/kg IV if healthcare-associated infection, MRSA risk, or severe sepsis is present. Check local protocol for renal dosing.
Do not routinely give antibiotics for uncomplicated spontaneous pneumomediastinum without evidence of perforation.

Definitive Care & Disposition

CT chest with IV contrast clarifies extent, pneumothorax, pleural fluid, airway injury, and alternate diagnoses. After forceful vomiting, severe odynophagia, fever, leukocytosis, pleural effusion, or concerning CT findings, obtain water-soluble contrast esophagram; if negative but suspicion remains, follow with thin barium or endoscopy with surgical consultation. Stable, low-risk spontaneous cases with reassuring imaging, controlled symptoms, and reliable follow-up may be observed briefly and discharged; admit patients with persistent symptoms, hypoxemia, significant pneumothorax, asthma exacerbation, trauma, or uncertain diagnosis. Esophageal or tracheobronchial injury requires ICU-level care, thoracic surgery, broad-spectrum antibiotics, drainage when indicated, and urgent source control.

How This One Kills

The lethal error is labeling post-emesis mediastinal air “spontaneous” and discharging a patient with esophageal rupture. Mediastinal contamination can be initially subtle; fever, pleural effusion, leukocytosis, systemic toxicity, and severe pain should override a reassuring early appearance.

The Differential — What Else Looks Like This

Pneumothorax — pleural line and absent peripheral lung markings; confusing it can delay decompression of tension physiology.
Esophageal rupture — vomiting followed by severe chest pain, fever, pleural effusion, or toxicity; missing it leads to mediastinitis.
Acute coronary syndrome — ischemic ECG/troponin pattern rather than subcutaneous emphysema; anchoring on air can miss myocardial infarction.
Necrotizing soft-tissue infection — rapidly progressive pain, skin change, and systemic toxicity; mistaking crepitus for benign air delays surgery.

The Second-Day Story

Older adults, immunocompromised patients, and partially treated patients may have little pain, fever, or palpable crepitus. A small unexplained mediastinal air collection, new pleural effusion, unexplained leukocytosis, or deterioration after vomiting is enough to reopen the question of perforation. The history of emesis, instrumentation, trauma, and positive-pressure exposure often carries more diagnostic value than the physical examination.

Back to Our Patient

Back to the 22-year-old with retching, neck crepitus, and mediastinal lucency: he is currently stable, but the vomiting mechanism makes an esophageal source important to exclude. CT chest with contrast shows pneumomediastinum without pleural fluid, pneumothorax, or perforation; a water-soluble esophagram is negative, and his lactate and examination remain reassuring. He receives oxygen, fentanyl for pain, and ondansetron for nausea, with no indication for empiric antibiotics. After observation without progression or hypoxemia, he is discharged with strict return precautions and rapid follow-up; any fever, worsening pain, dysphagia, dyspnea, or vomiting would mandate reassessment.

Patient Presentation to Attending

How you’d present this patient on the floor — tight, pertinent positives and negatives, no rambling

“This is a 22-year-old previously healthy man with acute upper chest and neck pain after forceful retching, with voice change and palpable cervical crepitus but no dyspnea, fever, hypotension, or peritoneal signs. He is speaking comfortably, saturating 98% on room air, and has stable vital signs. Chest radiography shows pneumomediastinum without tension pneumothorax. Given the vomiting trigger, I’m concerned about esophageal perforation despite his stable appearance. I’ll obtain CT chest with contrast and a water-soluble esophagram, provide analgesia and antiemetic therapy, and involve thoracic surgery if imaging or clinical status is concerning. If the workup remains negative and he tolerates oral intake, I’ll observe him briefly and discharge with strict return precautions.”

Study Directive

Draw the differential for mediastinal air from memory: spontaneous alveolar rupture, esophageal perforation, airway injury, trauma, and iatrogenic causes.
Review one CT image set each of benign pneumomediastinum and Boerhaave syndrome.
Practice stating the single risk-stratifying question—“Could this be an aerodigestive perforation?”—in three simulated cases.
Memorize the indications for esophagram and the antibiotic regimen; verify doses in your institutional reference.

Recent Literature

Review or guideline Pneumomediastinum
Grewal J, Gillaspie EA · Thorac Surg Clin, 2024 · PMID 39332856 · cited 7×

Provides a practical reference for distinguishing spontaneous from secondary pneumomediastinum, identifying dangerous aerodigestive injury, and guiding selective testing and management.

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Why Do We Intubate?

Intubation is not a response to an impressive number; it is a decision to replace failing airway protection, oxygenation, ventilation, or respiratory...

Listen: EM:RAP podcast →

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The Case

A 71-year-old man with fever and a wet cough leans forward over the edge of the bed, pulling hard against each breath. His words arrive in fragments, his hands are cool, and the monitor shows a respiratory rate of 36 despite high-flow oxygen. He is awake enough to answer his name but keeps drifting toward sleep as the blood gas is sent. The team must decide whether a tube will rescue him—or merely mark a failure to define the problem.

Before You Read

What are the actual physiologic reasons to intubate?
Which patients can safely receive a trial of noninvasive support?
What must be prepared before the sedative and paralytic are pushed?

Why It Matters

Intubation is not a response to an impressive number; it is a decision to replace failing airway protection, oxygenation, ventilation, or respiratory mechanics. The procedure itself can cause hypoxemia, hypotension, aspiration, and peri-intubation arrest, so the indication and preparation must be explicit.

When to Think of It

Intubate for inability to protect the airway, refractory hypoxemia, severe ventilatory failure with acidemia or exhaustion, impending respiratory arrest, severe upper-airway obstruction, or need for controlled ventilation during selected procedures or resuscitation. Consider the trajectory: worsening work of breathing, altered mentation, recurrent emesis, inability to clear secretions, and failure of appropriate noninvasive support often matter more than one blood-gas value.

Sick or Not Sick

Sick means immediate loss of airway protection, apnea, peri-arrest physiology, severe hypoxemia despite optimized oxygen delivery, shock with respiratory failure, or progressive exhaustion. The single call that matters most is: Will this patient remain safely oxygenated, ventilated, and protected for the next several minutes without a definitive airway?

The First Fifteen Minutes

Call for airway help, place the patient upright, attach ECG/SpO₂/continuous waveform capnography, obtain two IVs, and preoxygenate with a tight-fitting mask or noninvasive ventilation; this increases oxygen reserve during apnea.
If spontaneous breathing is inadequate or agonal → bag-valve-mask ventilation with 100% oxygen, using two-person technique and airway adjuncts, because assisted breaths restore alveolar ventilation.
If aspiration risk or significant secretions → aggressive suction before and during laryngoscopy, because removing material improves the view and reduces aspiration.
If hypotension before RSI → balanced crystalloid 500–1,000 mL IV bolus when fluid responsive, because optimizing preload reduces induction-related collapse; do not delay vasopressors in shock.
If vasopressor support is needed → norepinephrine 0.05–0.1 mcg/kg/min IV infusion, titrated to MAP, because α-mediated vasoconstriction preserves perfusion during induction. Dose ranges vary; use an institutional protocol.
If RSI is indicated and no contraindication → ketamine 1–2 mg/kg IV or etomidate 0.3 mg/kg IV for induction, because both provide rapid hypnosis with relative hemodynamic stability; ketamine may support sympathetic tone, while etomidate has minimal immediate cardiovascular depression.
Immediately after induction → rocuronium 1.2 mg/kg IV, because paralysis optimizes first-pass conditions and prevents coughing or laryngospasm. Confirm current local RSI guidance.
If peri-intubation bronchospasm → albuterol 2.5–5 mg nebulized, because β₂ stimulation reduces resistance; do not allow nebulization to delay a needed airway.
If post-intubation analgesia/sedation is required → fentanyl 25–50 mcg IV, repeated to effect, plus propofol 5–10 mcg/kg/min IV if blood pressure tolerates it; this prevents awareness and harmful sympathetic surges.

Definitive Care & Disposition

Choose the method based on urgency and anatomy: standard RSI with video or direct laryngoscopy, awake intubation for anticipated difficult oxygenation or airway anatomy, or surgical airway when obstruction prevents passage. Confirm with continuous waveform capnography, bilateral chest movement, and appropriate imaging when needed; secure the tube and start a disease-specific ventilator strategy. Treat the cause—antibiotics for sepsis, bronchodilators for asthma, diuresis or vasodilators for cardiogenic edema, reversal agents when appropriate—and admit to the ICU. A patient intubated solely for a transient procedure or reversible intoxication still requires a documented plan for sedation, ventilation, and liberation.

How This One Kills

The dangerous conceptual error is intubating because the oxygen saturation looks alarming while failing to prepare for hemodynamic collapse. Positive pressure removes the patient’s spontaneous preload contribution; induction vasodilation plus excessive ventilation can convert compensated shock into arrest.

The Atypical Presentation

Older adults, pregnant patients, and those with chronic lung disease may have little visible distress despite dangerous gas exchange failure; conversely, young patients with metabolic acidosis may appear dramatically tachypneic while still protecting the airway. Neuromuscular disease, intoxication, and fatigue can erase classic accessory-muscle use. Follow serial mental status, respiratory pattern, secretion handling, oxygen requirement, blood gas trajectory, and response to a properly selected noninvasive trial.

Back to Our Patient

Back to the 71-year-old with pneumonia, high work of breathing, hypoxemia despite high-flow oxygen, and drifting mentation: he is sick because oxygenation and respiratory mechanics are failing and airway protection is deteriorating. The team preoxygenates with noninvasive ventilation while preparing suction, video laryngoscopy, vasopressor support, and a post-intubation plan. After a balanced crystalloid bolus and norepinephrine initiation, ketamine and rocuronium facilitate RSI; waveform capnography confirms tracheal placement. He is started on lung-protective ventilation, broad-spectrum antibiotics for severe pneumonia, and ICU care.

Patient Presentation to Attending

“This is a 71-year-old man with fever and productive cough who has progressive hypoxemic respiratory failure despite high-flow oxygen, respiratory rate 36, marked work of breathing, and worsening somnolence. He can no longer speak full sentences and is at risk for losing airway protection; there is no history suggesting isolated panic or opioid toxicity. I recommend immediate controlled intubation rather than a prolonged noninvasive trial. I’ll preoxygenate with NIV, prepare suction and video laryngoscopy, optimize blood pressure with norepinephrine, and perform RSI with ketamine and rocuronium. After waveform confirmation, I’ll use lung-protective ventilation, begin treatment for severe pneumonia, and admit him to the ICU.”

Study Directive

Write the four primary indications for intubation—protection, oxygenation, ventilation, and mechanics—from memory.
Compare HFNC, CPAP, BiPAP, and invasive ventilation in four clinical vignettes.
Rehearse a 60-second RSI briefing including backup airway, suction, hemodynamic plan, induction, paralysis, capnography, and post-intubation settings.
Calculate induction and paralytic doses for a 70-kg and 120-kg adult.

Key Medications

Ketamine 1–2 mg/kg IV for RSI induction; lower doses may be used in shock, but dose selection varies—check an RSI reference.
Etomidate 0.3 mg/kg IV for RSI induction; some clinicians use 0.2 mg/kg in frail or profoundly shocked adults—verify local protocol.
Rocuronium 1.2 mg/kg IV for RSI paralysis.
Succinylcholine 1.5 mg/kg IV is an alternative paralytic when no hyperkalemia, neuromuscular disease, malignant-hyperthermia risk, or major crush injury contraindication exists; check current contraindication guidance.
Norepinephrine 0.05–0.1 mcg/kg/min IV infusion, titrate to perfusion/MAP; concentration and dosing vary by institution.
Fentanyl 25–50 mcg IV, repeated to effect, for post-intubation analgesia.
Propofol 5–10 mcg/kg/min IV, titrated; reduce or avoid in hypotension.
Naloxone 0.04–0.4 mg IV, titrated every 2–3 minutes for opioid-induced respiratory depression; larger doses may be needed in apnea. Pediatric dosing is weight-based.

High-Yield Pearls

The indication is physiologic failure or impending failure—not a specific respiratory rate or PaO₂ alone.
In severe metabolic acidosis, the patient’s high minute ventilation is compensatory; intubation without a plan to match it can cause immediate cardiovascular collapse.
Preparation for intubation includes the post-intubation ventilator and sedation plan before induction, not after the tube is secured.

The Mimics

Anxiety or panic — normal work of breathing, gas exchange, and trajectory; unnecessary intubation exposes the patient to avoidable airway and ventilator harm.
Metabolic acidosis — deep compensatory ventilation with a low PaCO₂; suppressing minute ventilation during intubation causes abrupt pH deterioration.
Opioid or sedative toxicity — depressed respiratory drive with preserved airway anatomy; confusing it with structural airway failure may delay naloxone.
Cardiogenic pulmonary edema — diffuse crackles and hypertension may improve with CPAP/BiPAP; immediate intubation without a noninvasive trial can increase complications when the patient is cooperative and protecting the airway.

Board Question

Which patient is the best candidate for a monitored trial of BiPAP rather than immediate intubation?

AObtunded patient with recurrent vomiting
BApneic patient with severe hypoxemia
CAlert patient with COPD exacerbation, pH 7.25, and intact airway protection
DPatient with progressive stridor from upper-airway obstruction

Reveal answer

Correct: C

An alert, cooperative patient with COPD-related hypercapnic acidosis who can protect the airway is a classic candidate for noninvasive ventilation. Obtundation, apnea, active emesis, and upper-airway obstruction are reasons to secure the airway rather than delay with NIV.

TheDaily Differential

Pneumomediastinum

When to Think of It

Sick or Not Sick

The First Fifteen Minutes

Definitive Care & Disposition

How This One Kills

The Second-Day Story

Study Directive

Recent Literature

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The Crashing Asthmatic

Why Do We Intubate?

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