Acute Infectious Stridor

Stridor, a harsh, grating respiratory sound often easily heard without a stethoscope, usually represents extrathoracic airflow obstruction. Although most often inspiratory, it can become biphasic in critical airway obstruction. The noise is caused by rapid, turbulent airflow through a narrowed airway. Poiseuille ’s Law states that airway resistance is inversely proportional to the radius of the airway to the fourth power. Therefore, a small change in airway diameter can have a large effect on resistance. Hence, pediatric patients, particularly infants with smaller airways, are especially susceptible to ch anges in airway caliber from inflammation, secretions, or edema.
Source: Pediatrics in Review - Category: Pediatrics Source Type: research