Frequency and morbidity of invasive procedures: report of a pilot study from two teaching hospitals.

The medical services of two teaching hospitals were assessed for the frequency of and complications from invasive procedures. There were 231 procedures performed on 303 patients. The frequency of procedures was significantly higher at one hospital (62% vs 39%, P less than .01). Twenty-nine complications occurred in 20 cases: 14% of patients who underwent procedures had at least one complication. Left-sided cardiac catheterization was the most common procedure. Procedures with more than one complication included the following: left-sided cardiac catherization (18% probability of complication); arteriovenous shunt (60% probability); thoracentesis (19%); bronchoscopy (25%); and percutaneous liver biopsy (8%). While no permanent damage or deaths were observed, over three fourths of the complications either required specific therapy or prolonged hospitalization or both. This study suggests invasive procedures are common and carry appreciable risks of serious complications. Appropriate clinical decision making and medical-legal protection require accurate estimates of those risks.