Related Experiment Videos
Pulmonary edema following relief of acute upper airway obstruction
Insights
Sudden airway pressure changes after artificial airway placement can cause acute pulmonary edema in children. Continuous positive airway pressure can help prevent this complication by allowing circulatory adaptation.
Area of Science:
- Pediatric Critical Care Medicine
- Respiratory Physiology
- Emergency Medicine
Background:
- Severe upper airway obstruction in children, including epiglottitis and laryngotracheobronchitis, presents a critical challenge.
- The management of airway obstruction often necessitates the placement of an artificial airway.
Observation:
- Five children (aged 1-5 years) with severe upper airway obstruction developed acute pulmonary edema post-artificial airway insertion.
- This complication occurred despite known contributing factors like hypoxemia and sympathetic discharge.
Findings:
- A specific physiological sequence is postulated: high transpulmonary pressure during inspiration, decreased venous return due to obstruction, and abrupt airway pressure fall post-insertion.
- This leads to increased venous return, elevated intravascular hydrostatic pressures, pulmonary hyperemia, and subsequent edema.
Implications:
- Early recognition of this physiological cascade is crucial for preventing post-obstructive pulmonary edema.
- Applying moderate continuous positive airway pressure during artificial airway insertion may facilitate circulatory adaptation and prevent edema.
Abstract:
Five children, aged one to five years, with severe upper airway obstruction, three of whom had epiglottitis and two of whom had laryngotracheobronchitis, developed acute pulmonary edema after the obstruction had been relieved by placement of an artificial airway. Although major physiologic changes, such as hypoxemia and massive sympathetic discharge, play a significant role in the development of acute pulmonary edema, we have postulated a possible etiological cause for the development of pulmonary edema in these children which involves a series of physiologic events. The generation of very high transpulmonary pressure gradients during inspiration is opposed by a decreased venous return due to the obstruction during exhalation. Airway pressures then fall abruptly with the insertion of the artifial airway, resulting in a sudden increase in venous return to the central circulation and marked increase in the intravascular hydrostatic pressures. The final result of this series of events is the development of pulmonary hyperemia and edema. The prevention of this situation must begin the moment the airway is inserted and involves the application of moderate amounts of continuous positive pressure to the airway, thus allowing time for circulatory adaption to take place.