(p. 505) Airflow limitation 

Exacerbations of asthma or chronic obstructive pulmonary disease (COPD) can be life-threatening emergencies, and require careful management to minimize the risks of morbidity and mortality. Prompt, full bronchodilator therapy, careful observation and appropriate mechanical ventilation technique is required. Dynamic hyperinflation of the lungs occurs in all patients, and must be careful assessed and regulated. Excessive dynamic hyperinflation can result in respiratory tamponade, hypotension, circulatory failure, pneumothoraces and, in severe cases, cardiac arrest. Intravenous or continuous nebulized salbutamol commonly causes lactic acidosis that should be detected and managed. Prolonged paralysis during difficult mechanical ventilation can result in severe necrotizing myopathy. Pneumothoraces in ventilated patients with asthma are usually under tension, redistribute ventilation to the contralateral lung, and risk a second tension pneumothorax. Patients surviving mechanical ventilation for asthma and COPD have an increased risk of recurrence and death. All these problems require awareness, avoidance or detection and management