| Etiology of respiratory distress | Clinical features, ventilator mechanics, bedside testing | Treatment |
| Ventilator and ventilator circuit |
| Incorrect ventilator settings (eg, tidal volume, fraction of inspired oxygen, inspiratory flow or pressure rate, positive end expiratory pressure, trigger sensitivity) | - Can occur when settings are inadequate or too high.
- Commonly found when ventilator settings are initiated or changed (eg, after intubation, procedures, or transport).
- May be less common with modern ventilators that automatically revert to previous settings when patients are temporarily removed from mechanical ventilation or settings are temporarily changed.
| - Disconnect the ventilator from the ETT.
- If respiratory distress resolves, examine the ventilator including settings and connections for problems.
- Once resolved, resume mechanical ventilation.
- If distress recurs, consider altering ventilator settings attempting to "match" patient effort (eg, increase the tidal volume or respiratory rate or switch to pressure support or pressure-controlled mode), ensuring new settings do not place the patient at risk of volutrauma or barotrauma.
- Consider replacement of the ventilator if distress persists.
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| Ventilator circuit leak or obstruction (including HME) | - Volume-controlled ventilation:
- Low peak pressures and low expired tidal volume may suggest a leak in the absence of a balloon cuff leak or cephalad displacement of the ETT (refer to below).
- High peak pressures, with widened delta Ppeak-Pplat*, may suggest obstruction.
- Pressure-controlled ventilation:
- Airway pressure unchanged, increase in tidal volume, and expiratory flow that does not return to baseline may suggest an air leak.
- Airway pressure unchanged, a decrease in tidal volume, and expiratory flow that is slow to return to baseline, suggest increased airway resistance from obstruction.
- A sawtooth pattern on ventilator graphics may suggest secretions or water in ventilator tubing as a source of obstruction.
- If no secretions are present in ventilator tubing, consider an obstruction at the level of the HME.
| - Replace the tubing if a leak is suspected.
- Empty the ventilator tubing of secretions.
- Replace the HME, if necessary.
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| Ventilator malfunction | - This issue is unusual but may be suspected when respiratory distress recurs despite resuming ventilation with the correct settings and no intrinsic parenchymal, airway, pleural, or extrapulmonary issues are suspected. May be determined during ventilator interrogation.
| - Consider replacing components of the ventilator or the ventilator itself.
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| Airway |
| | - Most conditions are associated with the following ventilatory mechanics:
- Increased Ppeak and a widened delta Ppeak-Pplat (volume-controlled ventilation).*
or - Unchanged airway pressure, decreased tidal volume, expiratory flow slow to return to baseline (pressure-controlled ventilation).
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| ETT obstruction – Mucus, blood, foreign body, kinking, or biting | - Known thick and voluminous secretions or hemoptysis.
- Foreign body such as a tooth may have been inhaled during intubation.
- Kinking in the ETT or biting may be obvious.
- Resistance to manual ventilation and passage of a suction catheter through the ETT.
- Maintenance of tidal volume, unless obstruction is complete.
| - Attempt to identify and remove the obstruction.
- Suctioning thick secretions often sufficient.
- Reposition the head especially if a kinked tube is suspected.
- Place bite block if biting of the ETT is suspected.
- If above measures fail, replace ETT.
- Bronchoscopy if problem persists.
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| Bronchospasm | - Often occurs in those with underlying obstructive lung disease but can also occur due to trauma in the airways (eg, suctioning, bronchoscopy), or medications (eg, beta blockers, allergies).
- Respiratory distress with wheeze or rhonchi.
- Maintenance of tidal volume.
| - Urgent bronchodilation with beta-2 agonists.
- Glucocorticoids, antihistamine, histamine receptor blockade, and epinephrine and may be administered if allergy is suspected.
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| Obstruction of lower airways by secretions, blood, airway mass, or foreign object | - Secretions of blood may be evident.
- Respiratory distress with wheeze or rhonchi (may be unilateral or focal).
- Tidal volume is maintained. Increased Ppeak* with widened delta Ppeak-Pplat.*
| - Attempt suctioning.
- Saline bullets sometime required to break up thick mucus plugs.
- Urgent bronchoscopy may be needed for foreign body retrieval, preferably with adequate suction channel and the ability to retrieve a foreign body if necessary.
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| Caudal migration of the ETT to mainstem bronchus (typically right-sided) | - Suspect in patients with agitation or in patients who have been repositioned.
- Air entry may be limited on the unaffected side and trachea may deviate away from the affected side.
- Respiratory distress with wheeze or rhonchi (may be unilateral or focal).
- Position of ETT at lips has been reduced (eg, moved from 22 cm to 20 cm at the lips).
- Tidal volume generally maintained. Increased Ppeak* with widened delta Ppeak-Pplat.*
- Capnography consistent with ETT positioned in the airway.
- Chest radiography or direct laryngoscopy confirm caudal migration.
| - Deflate the cuff and pull the ETT back by a predetermined amount.
- Re-image with chest radiography to confirm appropriate placement.
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| | - Most conditions are associated with the following ventilatory mechanics:
- Reduced Ppeak* with narrow or unchanged delta Ppeak-Pplat (volume-controlled ventilation).*
or - Unchanged airway pressure, increase in tidal volume, expiratory flow does not return to baseline (pressure controlled ventilation).
| |
| Balloon cuff leak, deflation, or rupture | - Audible leak (a gurgling sound due to air escaping through the glottis).
- Reduction in expired tidal volume compared with set tidal volume.
- Low cuff pressure.
- Capnography confirms airway placement.
| - Minor leaks – Reinflation of the balloon may suffice for mild air leaks.
- Major leaks – Replacement of the ETT is needed for large air leaks.
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| Cephalad migration of ETT above the vocal cords or into the esophagus | - Audible leak.
- Reduction in expired tidal volume compared with set tidal volume.
- Normal cuff pressure.
- Capnography and/or direct laryngoscopy confirms airway displacement.
| - Replace the ETT under direct laryngoscopy.
- Re-image with chest radiography to confirm appropriate placement.
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| Ventilatory circuit leak (refer to above) | | |
| Pulmonary parenchymal disease |
| | - Most conditions are associated with the following mechanics:
- Increased Ppeak* with narrow or unchanged delta Ppeak-Pplat (volume-controlled ventilation).*
or - Unchanged airway pressure, decrease in tidal volume, rapid return of expiratory flow toward baseline (pressure-controlled ventilation).
- Often occurs in association with a sudden decrease in oxygenation.
- Bedside chest radiography and ultrasonography and some laboratory tests are helpful diagnostically.
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| Atelectasis | - Recent change in secretions.
- Lobar collapse on imaging.
- Bronchoscopy may be needed to reveal the etiology, which is typically mucus plugs.
| - Refer to obstruction of lower airways (above).
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| Pneumonia | - All ventilated patients are at risk.
- New infiltrate on imaging, fever, elevated white blood cell count, change in secretions.
| - Treat with antibiotics according to suspected micro-organisms.
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| Pulmonary edema (cardiogenic or noncardiogenic) | - Known cardiac risk factors or recent myocardial infarction, or risk factors for noncardiogenic pulmonary edema.
- New murmur or additional heart sounds, crackles, elevated jugular venous pressure, increased brain natriuretic peptide.
- Pulmonary edema or Kerley B lines on bedside imaging.
- Bedside echocardiography may be helpful.
| - Diuresis and hemodynamic support if indicated.
- Treat the underlying cause.
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| Aspiration of oropharyngeal or gastroesophageal contents | - Recent vomiting, high residual volumes during tube feeding.
- New infiltrate on imaging may be apparent after a few hours or days.
| - Suctioning and elevation of the head of the bed at 45 degrees.
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| Pulmonary embolus (thrombo-, fat-, amniotic fluid-, or gas embolism) | - Acute respiratory distress in the expected clinical context (eg, cancer from thromboembolism, fractures for fat embolism, labor and delivery for amniotic fluid embolism, intravenous catheter insertion of air embolism).
- Bedside imaging sometimes helpful (eg, right ventricular dilatation, visible thrombus or air, lower-extremity thrombus).
| - Empiric anticoagulation may need to be considered if definitive testing for pulmonary embolism cannot be performed.
- High-flow oxygen may be needed to treat air embolism.
- Delivery of the fetus is necessary for amniotic fluid embolism.
- Treatment of fat embolism is supportive.
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| Pneumothorax (refer to below) | | |
| Dynamic hyperinflation | - Suspect in patients with high ventilatory requirements.
- DHI may be seen on ventilator graphics as inadequate return of expiratory flow to baseline before the next ventilator-delivered breath.
- An expiratory hold may be considered but may be inaccurate.
| - Reduce minute ventilation by reducing tidal volume and/or respiratory rate, reduce inspiratory time, and treat the underlying cause.
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| Pleural disease |
| | - Most conditions are associated with the following mechanics:
- Increased Ppeak* with narrow or unchanged delta Ppeak-Pplat (volume-controlled ventilation).*
or - Unchanged airway pressure, decrease in tidal volume, rapid return of expiratory flow toward baseline (pressure-controlled ventilation).
- Often occurs in association with a sudden decrease in oxygenation.
- Bedside chest radiography and ultrasonography are helpful diagnostically.
| |
| Pneumothorax (including tension pneumothorax) | - Can occur spontaneously or following a procedure or thoracic surgery.
- Tidal volume may be reduced if associated with a large bronchopleural fistula.
- Reduced-breath sounds on one side, tracheal deviation if tension is present.
| - Placement of a thoracostomy tube, if indicated.
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| Acute pleural effusion | - Can occur due to fluid overload or acutely following a procedure or thoracic surgery (eg, chylothorax, hemothorax).
- Reduced-breath sounds on affected side.
| - Large pleural effusions should be drained.
- Surgical exploration may be needed for large-volume chylothorax or hemothorax.
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| Extrapulmonary causes |
| | - Most conditions are associated with the following mechanics:
- Increased Ppeak* with narrow or unchanged delta Ppeak-Pplat (volume-controlled ventilation).*
or - Unchanged airway pressure, decrease in tidal volume, rapid return of expiratory flow toward baseline (pressure-controlled ventilation).
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| Abdominal distension (eg, ascites) | - May be apparent in patients with known condition (eg, chronic liver disease, pregnancy), or active abdominal process such as viscus rupture or colitis.
| - Large-volume thoracentesis.
- Treatment of underlying condition, if feasible.
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| Fever, delirium, anxiety, pain, acute neurologic event | - May be apparent in patients but are often diagnoses of exclusion.
| - Treat the symptom/sign (eg, anti-pyretics, anxiolytics, analgesics).
- Investigate and treat underlying cause.
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