Several underlying disease processes can result in respiratory distress, including primary lung disease, heart failure, pleural space disease, traumatic injury, and upper airway disease.
Because stress and handling can exacerbate respiratory disease, cats with dyspnea should initially be placed in an oxygen cage or administered flow-by oxygen on arrival. Respirations should be observed from afar, as the pattern can often indicate which part of the respiratory system is affected. Prolonged inspiratory and/or expiratory effort should be noted, as should any noises audible without the aid of a stethoscope; these are usually associated with upper airway obstruction. Thoracic and tracheal auscultation should be performed, along with an abbreviated physical examination, depending on patient stability.
Because cardiomyopathies are the most common form of heart disease in cats, many cats in respiratory distress associated with congestive heart failure do not have a heart murmur. Hypothermia is often noted in cats in heart failure. In addition, arrhythmias are often caused by primary heart disease.