OBJECTIVES: a) To evaluate the frequency, types, severity, and morbidity of 
iatrogenic complications; b) determine associated factors that favor iatrogenic 
complications; and c) suggest new or more efficient protective measures that may 
be taken to improve patient safety.
DESIGN: Prospective, observational study.
SETTING: Two ICUs in France.
PATIENTS AND METHODS: The study included 382 patients (age > or = 15 yrs; 400 
consecutive admissions). Patients were monitored by two physicians in each ICU 
to assess all iatrogenic complications occurring during their ICU stay, with the 
exception of adverse effects of drugs. An iatrogenic complication was defined as 
an adverse event that was independent of the patient's underlying disease.
RESULTS: We observed 316 iatrogenic complications in 124 (31%) of the 400 
admissions. Of these iatrogenic complications, 107 (in 53 [13%] of the 400 
admissions) complications were major, three leading to death. Severe 
hypotension, respiratory distress, pneumothorax, and cardiac arrest represented 
78% of the major iatrogenic complications. Fifty-nine percent of the major 
iatrogenic complications had clearly identified associated factors. Human errors 
accounted for 67% of these factors. Patients > 65 yrs (adjusted odds ratio = 
2.6, 95% confidence interval: 1.4 to 4.9) and those patients admitted with two 
or more organ failures (adjusted odds ratio = 4.8, 95% confidence interval: 2.5 
to 9.2) were more likely to develop major iatrogenic complications. High or 
excessive nursing workload also led to an increased risk of major iatrogenic 
complications. Persistent morbidity, secondary to iatrogenic complications at 
the time of discharge, was present in five survivors. The risk of ICU death was 
about two-fold higher for the patients with major iatrogenic complications than 
in the remaining patients after adjusting for the Organ System Failure Score and 
the prognosis of the disease (relative risk = 1.92, 95% confidence interval: 
1.28 to 2.56).
CONCLUSIONS: Major iatrogenic complications were frequent, associated with 
increased morbidity and mortality rates, related to high or excessive nursing 
workload, and were often secondary to human errors. To improve patient safety in 
our ICUs, preventive measures should be targeted primarily on the elderly and 
the most severely ill patients. Special attention should be given to improving 
the organization of workload and training, and promoting wider use of 
noninvasive monitoring.