Complications of Mechanical Aids to Intermittent Lung Inflation

Mechanical aids to intermittent lung inflation (treatments of 30 minutes or less) include IPPB, incentive spirometry, blow bottles, and intermittent CPAP. We consider true complications of their use to be those complications documented by one or more studies or by several case reports. Besides documented complications there are theore-tic or suggested complications. For IPPB, we identified three documented complica-tions: increased airway resistance, barotrauma, and nosocomial infection. Six other, theoretic complications of IPPB are: excessive oxygenation, gastric distention, hyper-ventilation, impaction of secretions, psychological dependence, and impedance of venous return. We found no documented complications of incentive spirometry; two theoretic complications are hyperventilation and barotrauma. For blow bottles, no documented complications exist; theoretic complications are hyperventilation, in-creased atelectasis, and barotrauma. For intermittent CPAP, no complications exist. We believe that the lack of documented complications of the use of these mechanical aids to intermittent lung inflation may have encouraged their widespread use despite the relative absence of documentation of their efficacy. Because these therapies are costly and of questionable value, cost-effective and efficacious methods of intermittent lung inflation should be encouraged.