Respiratory Therapy is categorize as an allied health profession in the United States and Canada. Formerly there was distinction between Certified Respiratory Therapy Technicians (CRTT) and Registered Respiratory Therapists (RRT), but in the United States, all Respiratory Care Practitioners (RCP) are now called Therapists, either Certified Respiratory Therapists (CRT) or Registered Respiratory Therapists (RRT). Respiratory Therapists (RTs) specialize in the assessment and treatment of respiratory and cardiovascular pathologies. These include chronic lung problems (e.g., asthma, bronchitis, emphysema, COPD), and more acute multi-systemic problems stemming from other pathological conditions such as heart attacks, stroke, or trauma as well as complications at birth. RTs are specialists in airway management, mechanical ventilation, blood acid/base balance, and critical care medicine. RTs work closely with other medical disciplines such as physicians, nurses, speech therapists and physical therapists etc.