Risks and hazards of mechanical ventilation: a collective review of published literature.

A collective, analytic review was undertaken of all available published scientific papers that reported data about risks, hazards, adverse effects, or complications from augmentation of blood gas exchange by means of intensive closed system positive pressure mechanical ventilation. On the basis of the data collected, the adverse effects of intensive positive pressure mechanical ventilation were classified into the following groups: oxygen toxicity; adverse effects from excessive ventilatory pressures, volumes, and flow rates; adverse effects from tracheal intubation; dangers from adjuvant drugs; stress-related sequelae; altered enzyme and hormone systems; nutritional problems; and psychologic trauma. A bibliography pertaining to each group of adverse effects has been prepared. In addition, the reported incidence of adverse effects resulting from intensive mechanical ventilation in patients in clinical intensive care is shown. Clinical and laboratory observations of patients who receive intensive positive pressure mechanical ventilation in respiratory intensive care units have yielded some data, and findings from experimental studies in normal volunteers and laboratory animals have also been collected and reviewed. Tables, charts, and graphs that summarize the pertinent findings are presented and discussed. The following conclusions are drawn from critical evaluation of the collected data: (1) Closed system positive pressure mechanical ventilation applied at mild to moderate levels of intensity is a safe and effective method for augmenting deficient blood gas exchange in most patients who are in acute respiratory failure. (2) On the other hand, intensive levels of mechanical ventilator support or inappropriate methods of applying mechanical ventilation may be accompanied by a variety of risks, hazards, adverse effects, and complications that may further injure the failing lungs or may add significantly to the morbidity and mortality rates of patients in whom it is applied. (3) Because of the unfavorable risk/benefit ratio of intensive positive pressure mechanical ventilation, physicians should consider the use of alternative methods that are now available for augmenting blood gas exchange in patients in acute respiratory failure who are not adequately treated by safe (mild to moderate) levels of positive pressure mechanical ventilation instead of electing to increase the intensity of positive pressure mechanical ventilation to more dangerous (intensive) levels.